U.S. patent application number 13/852719 was filed with the patent office on 2016-03-31 for high power laser energy distribution patterns, apparatus and methods for creating wells.
This patent application is currently assigned to Foro Energy Inc.. The applicant listed for this patent is Foro Energy Inc.. Invention is credited to Brian O. FAIRCLOTH, Yeshaya Koblick, Joel F. Moxley, Charles C. Rinzler, Mark S. Zediker.
Application Number | 20160090790 13/852719 |
Document ID | / |
Family ID | 41695291 |
Filed Date | 2016-03-31 |
United States Patent
Application |
20160090790 |
Kind Code |
A1 |
FAIRCLOTH; Brian O. ; et
al. |
March 31, 2016 |
HIGH POWER LASER ENERGY DISTRIBUTION PATTERNS, APPARATUS AND
METHODS FOR CREATING WELLS
Abstract
There is provided a system, apparatus and methods for providing
a laser beam to borehole surface in a predetermined and energy
deposition profile. The predetermined energy deposition profiles
may be uniform or tailored to specific downhole applications. Optic
assemblies for obtaining these predetermined energy deposition
profiles are further provided.
Inventors: |
FAIRCLOTH; Brian O.;
(Evergreen, CO) ; Zediker; Mark S.; (Castle Rock,
CO) ; Rinzler; Charles C.; (Denver, CO) ;
Koblick; Yeshaya; (Sharon, MA) ; Moxley; Joel F.;
(Denver, CO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Foro Energy Inc.; |
|
|
US |
|
|
Assignee: |
Foro Energy Inc.
Denver
CO
|
Family ID: |
41695291 |
Appl. No.: |
13/852719 |
Filed: |
March 28, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12544094 |
Aug 19, 2009 |
8424617 |
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13852719 |
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61090384 |
Aug 20, 2008 |
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61102730 |
Oct 3, 2008 |
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61106472 |
Oct 17, 2008 |
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61153271 |
Feb 17, 2009 |
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Current U.S.
Class: |
175/16 |
Current CPC
Class: |
E21B 29/00 20130101;
E21B 21/08 20130101; E21B 21/103 20130101; E21B 7/14 20130101; E21B
43/11 20130101; E21B 21/00 20130101; E21B 10/60 20130101; E21B 7/15
20130101 |
International
Class: |
E21B 7/15 20060101
E21B007/15 |
Goverment Interests
[0002] This invention was made with Government support under Award
DE-AR0000044 awarded by the Office of ARPA-E U.S. Department of
Energy. The Government has certain rights in this invention.
Claims
1-54. (canceled)
55. A system for forming a well in the earth comprising: a. a high
power laser source; b. a bottom hole assembly comprising a housing,
the housing defining a cavity; c. a fiber optically connecting the
laser source with the bottom hole assembly, such that a laser beam
from the laser source is transmitted to the bottom hole assembly;
d. a means for providing the laser beam to a strike of a borehole;
e. a beam power deposition optic having a property of changing an
energy distribution profile within the laser beam; and, f. the
cavity at least partially containing: i. the means for providing
the laser beam to the surface of the borehole; and, ii. the
providing means comprising the beam power deposition optic; g.
wherein, the laser beam as delivered from the bottom hole assembly
illuminates the surface of the borehole with a substantially even
energy deposition profile on the surface.
56. The system of claim 55, wherein the laser source provides a
plurality of laser beams to the fiber.
57. The system of claim 55, wherein the laser beam has a
substantially uniform profile at the fiber bottom hole assembly
connection.
58. The system of claim 55, wherein the laser beam is at least
about 20 kW at the fiber bottom hole assembly connection.
59. The system of claim 55, wherein the laser beam is at least
about 15 kW at the fiber bottom hole assembly connection.
60. The system of claim 55, wherein the laser source is at least
about 20 kW.
61. (canceled)
62. The system of claim 55, wherein the bottom hole assembly
comprises a motor.
63. The system of claim 55, wherein the surface of the borehole
comprises a bottom surface of the borehole.
64. The system of claim 55, wherein the bottom hole assembly
comprises an electric motor.
65. The system of claim 55, wherein the bottom hole assembly
comprises a means for transferring rotational motion.
66. A system for forming a borehole in the earth comprising: a. a
high power laser source; b. a laser delivery assembly; c. an
optical fiber comprising; i. a first and a second end; ii. a length
between the first and second ends; iii. the first end being
optically associated with the laser source; and, iv. the fiber
having a length of at least about 1000 ft; d. a means for
delivering a laser beam from the laser source to a surface of the
borehole, wherein the means includes a beam power deposition optic
having a property of changing an energy distribution profile within
the laser beam; and; e. the laser delivery means connected to and
optically associated with the second end of the optical fiber; f. a
means for providing a substantially uniform energy deposition; and,
g. the laser delivery means comprising the means for providing the
substantially uniform energy deposition.
67. The system of claim 66, wherein the laser delivery means
comprises an optical assembly.
68. The system of claim 66, wherein the laser delivery means is
contained within the laser delivery assembly.
69. The system of claim 66, wherein the laser delivery means is
contained within the laser delivery assembly and the laser delivery
assembly comprises a rotating optical assembly.
70. The system of claim 66, wherein the laser delivery assembly
comprises an electric motor.
71. The system of claim 66, wherein the laser source provides more
than one laser beam.
72. The system of claim 66, wherein the surface of the borehole
comprises a bottom surface of the borehole.
73. The system of claim 66, wherein the laser beam has a
substantially uniform profile at the fiber second end.
74. The system of claim 66, wherein the laser beam is at least
about 0.15 kW at the fiber second end.
75. The system of claim 66, wherein the laser source is from at
least about 40 kW.
76. The system of claim 66, wherein the laser source is at least
about 25 kW.
77. A system for creating a borehole comprising: a. a high power
laser source; b. a bottom hole assembly; c. a fiber optically
connecting the laser source with the bottom hole assembly, such
that a laser beam from the laser source is transmitted to the
bottom hole assembly; d. a means for providing the laser beam to a
surface of the borehole; and, e. a beam power deposition optic
having a property of changing an energy distribution profile within
the laser beam; f. the bottom hole assembly comprising: i. the
means for providing the laser beam to the surface of the borehole;
ii. the providing means comprising the beam power deposition optic;
and, iii. the means for providing the laser beam to the bottom
surface configured to provide a predetermined energy deposition
profile; g. wherein, the laser beam as delivered from the bottom
hole assembly illuminates the surface of the borehole with a
predetermined energy deposition profile.
78. The system of claim 77, wherein the predetermined energy
deposition profile is biased toward an outside area of a bottom
surface of the borehole surface.
79. The system of claim 77, wherein the predetermined energy
deposition profile is biased toward an inside area of a bottom
surface of the borehole surface.
80. The system of claim 77, comprising a mechanical removal
means.
81. The system of claim 77, wherein the laser beam at the bottom
hole assembly has a power of at least about 15 kW.
82. A system for advancing a borehole in the earth comprising: a. a
high power laser source; b. a bottom hole assembly; and, c. a fiber
optically connecting the laser source with the bottom hole
assembly, such that a laser beam from the laser source is
transmitted to the bottom hole assembly; d. the bottom hole
assembly comprising: a means for providing a laser beam to a bottom
surface of the borehole in a predetermined pattern, wherein the
means for providing it laser beam to a bottom surface of the
borehole further comprises a means for changing an energy
distribution profile within the laser, an wherein the predetermined
pattern is configured to illuminate a majority of the borehole
bottom surface and in a predetermined energy deposition
profile.
83. The system of claim 82, wherein the laser beam at the bottom
hole assembly has a power of at least about 15 kW.
84. A system for creating a borehole comprising: a. a high power
laser source; b. a bottom hole assembly; and, c. a fiber optically
connecting the laser source with the bottom hole assembly, such
that a laser beam from the laser source is transmitted to the
bottom hole assembly, the laser beam at the bottom hole assembly
having a power of at least about: 5 kW; d. the bottom hole assembly
comprising: a means for providing it substantially elliptical
shaped laser beam spot having a power of at least about 5 kW to the
bottom surface of the borehole in a rotating manner to thereby
provide a predetermined energy deposition profile to the bottom
surface of the borehole.
85. A method of forming a borehole using a laser, the method
comprising: a. advancing a high power laser beam transmission fiber
into a borehole; i. the borehole having a bottom, a side wall, a
top opening, and a length extending between the bottom and the top
opening of at least about 5000 feet; ii. the transmission fiber
comprising a distal end, a proximal end, and a length extending
between the distal and proximal ends, the distal end being advanced
into the borehole; iii. the transmission means comprising a means
for transmitting high power laser energy, b. providing a laser
beam, having a power of least about 10 kW, to the proximal end of
the transmission fiber; c. transmitting the power of the laser been
down the length of the transmission fiber so that the beam exits
the distal end, having a first energy distribution profile, and
enters a laser delivery assembly; and, d. directing the laser beam,
having a power of at least about 5 kW, and having the second energy
distribution profile, in a predetermined pattern defining a pattern
area; and, wherein the predetermined pattern provides a
predetermined and substantially uniform energy deposition profile
to a surface of the borehole, whereby the borehole is completed, in
part, based upon the interaction of the laser beam with the surface
of the borehole.
86. A system for creating a hole comprising: a. a high power laser
source generating a high power laser beam, b. a bottom hole
assembly comprising: a means for providing the high power laser
beam to a bottom surface of a borehole, wherein the means for
providing the high power laser beam comprises beam power deposition
optics; c. a fiber optically connecting the high power laser source
with the bottom hole assembly, such that the high power laser beam
from the high power laser source is transmitted to the bottom hole
assembly, the high power laser beam at the bottom hole assembly
having a power of at least about 1 kW; d. wherein, the high power
laser beam as delivered from the bottom hole assembly illuminates a
bottom surface of the borehole with the high power laser beam
having a power of at least about 0.1 kW in a substantially even
energy deposition profile on the bottom surface.
87. The system of claim 86, wherein the laser bottom hole assembly
comprises a housing defining a cavity.
88. A system for creating a borehole in the earth comprising: a. a
high power laser source; b. a bottom hole assembly; c. an optical
fiber comprising: i. a first end and a second end; ii. a length
between the first and second ends that is at least 1000 ft; and,
iii. the first end being optically associated with the laser
source; d. a means for delivering a laser beam from the laser
source to a surface of the borehole, wherein the means for
delivering a laser beam comprises a means for providing a
substantially uniform energy deposition to the bottom of the
borehole and is connected to and optically associated with the
second end of the optical fiber.
89. A system for creating a borehole in the earth comprising: a. a
high power laser source; b. a bottom hole assembly; and, c. a fiber
optically connecting the high power laser source with the bottom
hole assembly, such that a high power laser beam from the laser
source is transmitted to the bottom hole assembly, the high power
laser beam in the fiber having a power of at least about 5 kW; d.
the bottom hole assembly comprising: a means for providing a laser
beam shot pattern to an area of the borehole in a predetermined
shot pattern configured to illuminate a majority of the area with a
laser beam having a power of at least about 5 kW and in a
predetermined energy deposition profile to the area.
90. A system for creating a borehole in the earth comprising: a. a
high power laser source; b. a bottom hole assembly; and, c. a fiber
optically connecting the high power laser source with the bottom
hole assembly, such that a high power laser beam from the laser
source is transmitted to the bottom hole assembly, the high power
laser beam in the fiber at the fiber having a power of at as about
5 kW; d. the bottom hole assembly comprising: a means for providing
a substantially elliptical shaped laser beam spot having at power
of at least about: 5 kW to the bottom surface of the borehole in a
rotating manner to thereby provide a predetermined energy
deposition to the bottom surface of the borehole.
91. A method of forming a borehole using a laser, the method
comprising: a. advancing a transmission fiber into a borehole; i.
the borehole having a bottom surface, a top opening, and a length
extending between the bottom surface and the top opening of at
least about 1000 feet; ii. the transmission fiber comprising a
distal end, a proximal end, and a length extending between the
distal and proximal ends, the distal end being advanced down the
borehole; b. providing a laser beam, having at: least about 10 kW,
to the proximal end of the transmission means; c. transmitting the
power of the laser beam down the length of the transmission fiber
so that the beam exits the distal end and enters a laser bottom
hole assembly; and, d. directing the laser beam, having at least
about 5 kW, in a predetermined pattern to provide a predetermined
and substantially uniform energy deposition profile to the surface
of the borehole whereby the length of the borehole is increased, in
part, based upon the interaction of the laser beam with the bottom
of the borehole.
92. A system for creating a hole comprising: a. a high power laser
source generating a high power laser beam; b. a laser delivery
assembly comprising: an optics configuration capable of providing
the high power laser beam to a bottom surface of a borehole,
wherein the optics configuration comprises beam power deposition
optics; c. a fiber optically connecting the high power laser source
with the laser delivery assembly, such that the high power laser
beam from the high power laser source is transmitted to the laser
delivery assembly, the high power laser beam at the laser delivery
assembly having a power of at least about 1 kW; d. wherein, the
high power laser beam as delivered from the bottom hole assembly
illuminates a bottom surface of the borehole with the high power
laser beam having a power of at least about 1 kW in a substantially
even energy deposition profile on the bottom surface.
93. A system for creating a borehole in the earth comprising: a. a
high power laser source; b. a bottom hole assembly; an optical
fiber comprising: a first end and a second end; a length between
the first and second ends that is at least 1000 ft; the first end
being optically associated with the laser source; d. a laser
delivery assembly capable of delivering a laser beam from the laser
source to a surface of the borehole, wherein the laser delivery
assembly comprises a means for providing a substantially uniform
energy deposition to the bottom of the borehole and is connected to
and optically associated with the second end of the optical
fiber.
94. A system for creating a borehole in the earth comprising: a. a
high power laser source; b. a bottom hole assembly; and, c. a fiber
optically connecting the high power laser source with the bottom
hole assembly, such that a high power laser beam from the laser
source is transmitted to the bottom hole assembly, the high power
laser beam in the fiber having a power of at least about 5 kW; d.
the bottom hole assembly comprising: an optical assembly capable of
providing a laser beam shot pattern to an area of the borehole in a
predetermined shot pattern configured to illuminate a majority of
the area with a laser beam having a power of at least about 5 kW
and in a predetermined energy deposition profile to the area.
95. The system of claim 94, wherein the optical assembly contains a
beam power deposition optic having a property of changing an energy
distribution profile within the laser beam.
Description
[0001] This application is a continuation of Ser. No. 12/544,094
filed Aug. 19, 2008 and which claims the benefit of priority of
provisional applications: Ser. No. 61/090,384 filed Aug. 20, 2008,
titled System and Methods for Borehole Drilling: Ser. No.
61/102,730 filed Oct. 3, 2008, titled Systems and Methods to
Optically Pattern Rock to Chip Rock Formations; Ser. No. 61/106,472
filed Oct. 17, 2008, titled Transmission of High Optical Power
Levels via Optical Fibers for Applications such as Rock Drilling
and Power Transmission; and, Ser. No. 61/153,271 filed Feb. 17,
2009, title Method and Apparatus for an Armored High Power Optical
Fiber for Providing Boreholes in the Earth, the disclosures of
which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0003] The present invention relates to methods, apparatus and
systems for delivering high power laser energy over long distances,
while maintaining the power of the laser energy to perform desired
tasks. In a particular, the present invention relates to optics,
beam profiles and laser spot patterns for use in and delivery from
a laser bottom hole assembly (LBHA) for delivering high power laser
energy to the bottom of a borehole to create and advance a borehole
in the earth.
[0004] In general, boreholes have been formed in the earth's
surface and the earth, i.e., the ground, to access resources that
are located at and below the surface. Such resources would include
hydrocarbons, such as oil and natural gas, water, and geothermal
energy sources, including hydrothermal wells. Boreholes have also
been formed in the ground to study, sample and explore materials
and formations that are located below the surface. They have also
been formed in the ground to create passageways for the placement
of cables and other such items below the surface of the earth.
[0005] The term borehole includes any opening that is created in
the ground that is substantially longer than it is wide, such as a
well, a well bore, a well hole, and other terms commonly used or
known in the art to define these types of narrow long passages in
the earth. Although boreholes are generally oriented substantially
vertically, they may also be oriented on an angle from vertical, to
and including horizontal. Thus, using a level line as representing
the horizontal orientation, a borehole can range in orientation
from 0.degree. i.e., a vertical borehole, to 90.degree.,i.e., a
horizontal borehole and greater than 90.degree. e.g., such as a
heel and toe. Boreholes may further have segments or sections that
have different orientations, they may be arcuate, and they may be
of the shapes commonly found when directional drilling is employed.
Thus, as used herein unless expressly provided otherwise, the
"bottom" of the borehole, the "bottom" surface of the borehole and
similar terms refer to the end of the borehole, i.e., that portion
of the borehole farthest along the path of the borehole from the
borehole's opening, the surface of the earth, or the borehole's
beginning.
[0006] Advancing a borehole means to increase the length of the
borehole. Thus, by advancing a borehole, other than a horizontal
one, the depth of the borehole is also increased. Boreholes are
generally formed and advanced by using mechanical drilling
equipment having a rotating drilling bit. The drilling bit is
extending to and into the earth and rotated to create a hole in the
earth. In general, to perform the drilling operation a diamond tip
tool is used. That tool must be forced against the rock or earth to
be cut with a sufficient force to exceed the shear strength of that
material. Thus, in conventional drilling activity mechanical forces
exceeding the shear strength of the rock or earth must be applied
to that material. The material that is cut from the earth is
generally known as cuttings, i.e., waste, which may be chips of
rock, dust, rock fibers, and other types of materials and
structures that may be created by thermal or mechanical
interactions with the earth. These cuttings are typically removed
from the borehole by the use of fluids, which fluids can be
liquids, foams or gases.
[0007] In addition to advancing the borehole, other types of
activities are performed in or related to forming a borehole, such
as, work over and completion activities. These types of activities
would include for example the cutting and perforating of casing and
the removal of a well plug. Well casing, or casing, refers to the
tubulars or other material that are used to line a wellbore. A well
plug is a structure, or material that is placed in a borehole to
fill and block the borehole. A well plug is intended to prevent or
restrict materials from flowing in the borehole.
[0008] Typically, perforating, i.e., the perforation activity,
involves the use of a perforating tool to create openings, e.g.
windows, or a porosity in the casing and borehole to permit the
sought after resource to flow into the borehole. Thus, perforating
tools may use an explosive charge to create, or drive projectiles
into the casing and the sides of the borehole to create such
openings or porosities.
[0009] The above mentioned conventional ways to form and advance a
borehole are referred to as mechanical techniques, or mechanical
drilling techniques, because they require a mechanical interaction
between the drilling equipment, e.g., the drill bit or perforation
tool, and the earth or casing to transmit the force needed to cut
the earth or casing.
[0010] It has been theorized that lasers could be adapted for use
to form and advance a borehole. Thus, it has been theorized that
laser energy from a laser source could be used to cut rock and
earth through spalling, thermal dissociation, melting, vaporization
and combinations of these phenomena. Melting involves the
transition of rock and earth from a solid to a liquid state.
Vaporization involves the transition of rock and earth from either
a solid or liquid state to a gaseous state. Spalling involves the
fragmentation of rock from localized heat induced stress effects.
Thermal dissociation involves the breaking of chemical bonds at the
molecular level.
[0011] To date it is believed that no one has succeeded in
developing and implementing these laser drilling theories to
provide an apparatus, method or system that can advance a borehole
through the earth using a laser, or perform perforations in a well
using a laser. Moreover, to date it is believed that no one has
developed the parameters, and the equipment needed to meet those
parameters, for the effective cutting and removal of rock and earth
from the bottom of a borehole using a laser, nor has anyone
developed the parameters and equipment need to meet those
parameters for the effective perforation of a well using a laser.
Further is it believed that no one has developed the parameters,
equipment or methods need to advance a borehole deep into the
earth, to depths exceeding about 300 ft (0.09 km), 500 ft (0.15
km), 1000 ft, (0.30 km), 3,280 ft (1 km), 9,840 ft (3 km) and
16,400 ft (5 km), using a laser. In particular, it is believed that
no one has developed parameters, equipments, or methods nor
implemented the delivery of high power laser energy, i.e., in
excess of 1 kW or more to advance a borehole within the earth.
[0012] While mechanical drilling has advanced and is efficient in
many types of geological formations, it is believed that a highly
efficient means to create boreholes through harder geologic
formations, such as basalt and granite has yet to be developed.
Thus, the present invention provides solutions to this need by
providing parameters, equipment and techniques for using a laser
for advancing a borehole in a highly efficient manner through
harder rock formations, such as basalt and granite.
[0013] The environment and great distances that are present inside
of a borehole in the earth can be very harsh and demanding upon
optical fibers, optics, and packaging. Thus, there is a need for
methods and an apparatus for the deployment of optical fibers,
optics, and packaging into a borehole, and in particular very deep
boreholes, that will enable these and all associated components to
withstand and resist the dirt, pressure and temperature present in
the borehole and overcome or mitigate the power losses that occur
when transmitting high power laser beams over long distances. The
present inventions address these needs by providing a long distance
high powered laser beam transmission means.
[0014] It has been desirable, but prior to the present invention
believed to have never been obtained, to deliver a high power laser
beam over a distance within a borehole greater than about 300 ft
(0.90 km), about 500 ft (0.15 km), about 1000 ft, (0.30 km), about
3,280 ft (1 km), about 9,8430 ft (3 km) and about 16,400 ft (5 km)
down an optical fiber in a borehole, to minimize the optical power
losses due to non-linear phenomenon, and to enable the efficient
delivery of high power at the end of the optical fiber. Thus, the
efficient transmission of high power from point A to point B where
the distance between point A and point B within a borehole greater
than about 1,640 ft (0.5 km) has long been desirable, but prior to
the present invention is believed to have never been obtainable and
specifically believed to have never been obtained in a borehole
drilling activity. The present invention addresses this need by
providing an LBHA and laser optics to deliver a high powered laser
beam to downhole surfaces in a borehole.
[0015] A conventional drilling rig, which delivers power from the
surface by mechanical means, must create a force on the rock that
exceeds the shear strength of the rock being drilled. Although a
laser has been shown to effectively spall and chip such hard rocks
in the laboratory under laboratory conditions, and it has been
theorized that a laser could cut such hard rocks at superior net
rates than mechanical drilling, to date it is believed that no one
has developed the apparatus systems or methods that would enable
the delivery of the laser beam to the bottom of a borehole that is
greater than about 1,640 ft (0.5 km) in depth with sufficient power
to cut such hard rocks, let alone cut such hard rocks at rates that
were equivalent to and faster than conventional mechanical
drilling. It is believed that this failure of the art was a
fundamental and long standing problem for which the present
invention provides a solution.
[0016] The environment and great distances that are present inside
of a borehole in the earth can be harsh and demanding upon optics
and optical fibers. Thus, there is a need for methods and an
apparatus for the delivery of high power laser energy very deep in
boreholes that will enable the delivery device to withstand and
resist the dirt, pressure and temperature present in the borehole.
The present invention addresses this need by providing an LBHA and
laser optics to deliver a high powered laser beam to downhole
surfaces of a borehole.
[0017] Thus the present invention addresses and provides solutions
to these and other needs in the drilling arts by providing, among
other things optics, beam profiles and laser spot patterns for use
in and delivery from an LBHA to provide the delivery of high
powered laser beam energy to the surfaces of a borehole.
SUMMARY
[0018] It is desirable to develop systems and methods that provide
for the delivery of high power laser energy to the bottom of a deep
borehole to advance that borehole at a cost effect rate, and in
particular, to be able to deliver such high power laser energy to
drill through rock layer formations including granite, basalt,
sandstone, dolomite, sand, salt, limestone, rhyolite, quartzite and
shale rock at a cost effective rate. More particularly, it is
desirable to develop systems and methods that provide for the
ability to be able to deliver such high power laser energy to drill
through hard rock layer formations, such as granite and basalt, at
a rate that is superior to prior conventional mechanical drilling
operations. The present invention, among other things, solves these
needs by providing the system, apparatus and methods taught
herein.
[0019] Thus, there is provided a system for creating a borehole in
the earth having a high power laser source, a bottom hole assembly
and, a fiber optically connecting the laser source with the bottom
hole assembly, such that a laser beam from the laser source is
transmitted to the bottom hole assembly the bottom hole assembly
comprising: a means for providing the laser beam to a bottom
surface of the borehole; the providing means comprising beam power
deposition optics; wherein, the laser beam as delivered from the
bottom hole assembly illuminates the bottom surface of the borehole
with a substantially even energy deposition profile.
[0020] There is further provided a system for creating a borehole
in the earth comprising: a high power laser source; a bottom hole
assembly; an optical fiber, having a first and a second end, having
a length between the first and second ends, the first end being
optically associated with the laser source and the fiber having a
length of at least about 1000 ft; a means for delivering a laser
beam from the laser source to a surface of the borehole; the laser
delivery means connected to and optically associated with the
second end of the optical fiber; and, a means for providing a
substantially uniform energy deposition.
[0021] There is additionally provided a system and method for
creating a borehole in the earth wherein the system and method
employ means for providing the laser beam to the bottom surface in
a predetermined energy deposition profile, including having the
laser beam as delivered from the bottom hole assembly illuminating
the bottom surface of the borehole with a predetermined energy
deposition profile, illuminating the bottom surface with an any one
of or combination of: a predetermined energy deposition profile
biased toward the outside area of the borehole surface; a
predetermined energy deposition profile biased toward the inside
area of the borehole surface; a predetermined energy deposition
profile comprising at least two concentric areas having different
energy deposition profiles; a predetermined energy deposition
profile provided by a scattered laser shot pattern; a predetermined
energy deposition profile based upon the mechanical stresses
applied by a mechanical removal means; a predetermined energy
deposition profile having at least two areas of differing energy
and the energies in the areas correspond inversely to the
mechanical forces applied by a mechanical means.
[0022] There is yet further provided a method of advancing a
borehole using a laser, the method comprising: advancing a high
power laser beam transmission means into a borehole; the borehole
having a bottom surface, a top opening, and a length extending
between the bottom surface and the top opening of at least about
1000 feet; the transmission means comprising a distal end, a
proximal end, and a length extending between the distal and
proximal ends, the distal end being advanced down the borehole; the
transmission means comprising a means for transmitting high power
laser energy; providing a high power laser beam to the proximal end
of the transmission means; transmitting substantially all of the
power of the laser beam down the length of the transmission means
so that the beam exits the distal end; transmitting the laser beam
from the distal end to an optical assembly in a laser bottom hole
assembly, the laser bottom hole assembly directing the laser beam
to the bottom surface of the borehole; and, providing a
predetermined energy deposition profile to the bottom of the
borehole; whereby the length of the borehole is increased, in part,
based upon the interaction of the laser beam with the bottom of the
borehole.
[0023] Moreover there is provided a method of advancing a borehole
using a laser, wherein the laser beam is directed to the bottom
surface of the borehole in a substantially uniform energy
deposition profile and thereby the length of the borehole is
increased, in part, based upon the interaction of the laser beam
with the bottom of the borehole.
[0024] Still further there is provided a method of advancing a
borehole using a laser, wherein the laser beam is directed in a
predetermined pattern to provide a predetermined energy deposition
profile to the bottom surface of the borehole whereby the length of
the borehole is increased, in part, based upon the interaction of
the laser beam with the bottom of the borehole.
[0025] The foregoing systems and methods may further employ more
than one laser beams, a plurality of laser beams, a laser beam with
a Gaussian profile at the fiber bottom hole assembly connection, a
substantially Gaussian profile at the fiber bottom hole assembly
connection, a super-Gaussian profile at the fiber bottom hole
assembly connection, or a laser beam with substantially uniform
profile at the fiber bottom hole assembly connection.
[0026] The forgoing systems and methods may also employ a laser
delivery means comprising an optical assembly, a rotating optical
assembly, a mud motor, a micro-optics array, or an axicon lens.
[0027] The forgoing systems and methods may further employ a laser
beam having at least about 1 kW, 3 kW, 5 kW, 10 kW, or 15 kW at the
down hole end of the fiber. These systems and methods may employ
laser sources from at least about 5 kW to about 20 kW, at least
about 15 kW, at least about 5 kW.
[0028] One of ordinary skill in the art will recognize, based on
the teachings set forth in these specifications and drawings, that
there are various embodiments and implementations of these
teachings to practice the present invention. Accordingly, the
embodiments in this summary are not meant to limit these teachings
in any way.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIGS. 1A and 1B, is a graphic representation of an example
of a laser beam basalt illumination.
[0030] FIGS. 2A and 2B illustrate the energy deposition profile of
an elliptical spot rotated about its center point for a beam that
is either uniform or Gaussian.
[0031] FIG. 3A shows the energy deposition profile with no
rotation.
[0032] FIG. 3B shows the substantially even and uniform energy
deposition profile upon rotation of the beam that provides the
energy deposition profile of FIG. 3A.
[0033] FIGS. 4A to 4D illustrate an optical assembly.
[0034] FIG. 5 illustrates an optical assembly.
[0035] FIG. 6 illustrates an optical assembly.
[0036] FIGS. 7A and 7B illustrate optical assemblies.
[0037] FIG. 8 illustrates a multi-rotating laser shot pattern.
[0038] FIG. 9 illustrates an elliptical shaped shot.
[0039] FIG. 10 illustrates a rectangular shaped spot.
[0040] FIG. 11 illustrates a multi-shot shot pattern.
[0041] FIG. 12 illustrates a shot pattern.
[0042] FIG. 13A is a perspective view of an LBHA.
[0043] FIG. 13B is a cross sectional view of the LBHA of FIG. 13A
taken along B-B.
[0044] FIG. 14 is a laser drilling system.
[0045] FIGS. 15 to 25 illustrate LBHAs.
DESCRIPTION OF THE DRAWINGS AND THE PREFERRED EMBODIMENTS
[0046] In general, the present inventions relate to methods,
apparatus and systems for use in laser drilling of a borehole in
the earth, and further, relate to equipment, methods and systems
for the laser advancing of such boreholes deep into the earth and
at highly efficient advancement rates. These highly efficient
advancement rates are obtainable in part because the present
invention provides for optics, beam profiles and laser spot
patterns for use in and delivery from a laser bottom hole assembly
(LBHA) that shapes and delivers the high power laser energy to the
surfaces of the borehole. As used herein the term "earth" should be
given its broadest possible meaning (unless expressly stated
otherwise) and would include, without limitation, the ground, all
natural materials, such as rocks, and artificial materials, such as
concrete, that are or may be found in the ground, including without
limitation rock layer formations, such as, granite, basalt,
sandstone, dolomite, sand, salt, limestone, rhyolite, quartzite and
shale rock.
[0047] In general, one or more laser beams generated or illuminated
by one or more lasers may spall, vaporize or melt material such as
rock or earth. The laser beam may be pulsed by one or a plurality
of waveforms or it may be continuous. The laser beam may generally
induce thermal stress in a rock formation due to characteristics of
the rock including, for example, the thermal conductivity. The
laser beam may also induce mechanical stress via superheated steam
explosions of moisture in the subsurface of the rock formation.
Mechanical stress may also be induced by thermal decomposition and
sublimation of part of the in situ minerals of the material.
Thermal and/or mechanical stress at or below a laser-material
interface may promote spallation of the material, such as rock.
Likewise, the laser may be used to effect well casings, cement or
other bodies of material as desired. A laser beam may generally act
on a surface at a location where the laser beam contacts the
surface, which may be referred to as a region of laser
illumination. The region of laser illumination may have any
preselected shape and intensity distribution that is required to
accomplish the desired outcome, the laser illumination region may
also be referred to as a laser beam spot. Boreholes of any depth
and/or diameter may be formed, such as by spalling multiple points
or layers. Thus, by way of example, consecutive points may be
targeted or a strategic pattern of points may be targeted to
enhance laser/rock interaction. The position or orientation of the
laser or laser beam may be moved or directed so as to intelligently
act across a desired area such that the laser/material interactions
are most efficient at causing rock removal.
[0048] Generally in downhole operations including drilling,
completion, and workover, the bottom hole assembly is an assembly
of equipment that typically is positioned at the end of a cable,
wireline, umbilical, string of tubulars, string of drill pipe, or
coiled tubing and is lower into and out of a borehole. It is this
assembly that typically is directly involved with the drilling,
completion, or workover operation and facilitates an interaction
with the surfaces of the borehole, casing, or formation to advance
or otherwise enhance the borehole as desired.
[0049] In general, the LBHA may contain an outer housing that is
capable of withstanding the conditions of a downhole environment, a
source of a high power laser beam, and optics for the shaping and
directing a laser beam on the desired surfaces of the borehole,
casing, or formation. The high power laser beam may be greater than
about 1 kW, from about 2 kW to about 20 kW, greater than about 5
kW, from about 5 kW to about 10 kW, at least about 10 kW,
preferably at least about 15 kW, and more preferably at least about
20 kW. The assembly may further contain or be associated with a
system for delivering and directing fluid to the desired location
in the borehole, a system for reducing or controlling or managing
debris in the laser beam path to the material surface, a means to
control or manage the temperature of the optics, a means to control
or manage the pressure surrounding the optics, and other components
of the assembly, and monitoring and measuring equipment and
apparatus, as well as, other types of downhole equipment that are
used in conventional mechanical drilling operations. Further, the
LBHA may incorporate a means to enable the optics to shape and
propagate the beam which for example would include a means to
control the index of refraction of the environment through which
the laser is propagating. Thus, as used herein the terms control
and manage are understood to be used in their broadest sense and
would include active and passive measures as well as design choices
and materials choices.
[0050] The LBHA should be construed to withstand the conditions
found in boreholes including boreholes having depths of about 1,640
ft (0.5 km) or more, about 3,280 ft (1 km) or more, about 9,830 ft
(3 km) or more, about 16,400 ft (5 km) or more, and up to and
including about 22,970 ft (7 km) or more. While drilling, i.e.
advancement of the borehole, is taking place the desired location
in the borehole may have dust, drilling fluid, and/or cuttings
present. Thus, the LBHA should be constructed of materials that can
withstand these pressures, temperatures, flows, and conditions, and
protect the laser optics that are contained in the LBHA. Further,
the LBHA should be designed and engineered to withstand the
downhole temperatures, pressures, and flows and conditions while
managing the adverse effects of the conditions on the operation of
the laser optics and the delivery of the laser beam.
[0051] The LBHA should also be constructed to handle and deliver
high power laser energy at these depths and under the extreme
conditions present in these deep downhole environments. Thus, the
LBHA and its laser optics should be capable of handling and
delivering laser beams having energies of 1 kW or more, 5 kW or
more, 10 kW or more and 20 kW or more. This assembly and optics
should also be capable of delivering such laser beams at depths of
about 1,640 ft (0.5 km) or more, about 3,280 ft (1 km) or more,
about 9,830 ft (3 km) or more, about 16,400 ft (5 km) or more, and
up to and including about 22,970 ft (7 km) or more.
[0052] The LBHA should also be able to operate in these extreme
downhole environments for extended periods of time. The lowering
and raising of a bottom hole assembly has been referred to as
tripping in and tripping out. While the bottom hole assembling is
being tripped in or out the borehole is not being advanced. Thus,
reducing the number of times that the bottom hole assembly needs to
be tripped in and out will reduce the critical path for advancing
the borehole, i.e., drilling the well, and thus will reduce the
cost of such drilling. (As used herein the critical path referrers
to the least number of steps that must be performed in serial to
complete the well.) This cost savings equates to an increase in the
drilling rate efficiency. Thus, reducing the number of times that
the bottom hole assembly needs to be removed from the borehole
directly corresponds to reductions in the time it takes to drill
the well and the cost for such drilling. Moreover, since most
drilling activities are based upon day rates for drilling rigs,
reducing the number of days to complete a borehole will provided a
substantial commercial benefit. Thus, the LBHA and its laser optics
should be capable of handling and delivering laser beams having
energies of 1 kW or more, 5 kW or more, 10 kW or more and 20 kW or
more at depths of about 1,640 ft (0.5 km) or more, about 3,280 ft
(1 km) or more, about 9,830 ft (3 km) or more, about 16,400 ft (5
km) or more, and up to and including about 22,970 ft (7 km) or
more, for at least about 1/2 hr or more, at least about 1 hr or
more, at least about 2 hours or more, at least about 5 hours or
more, and at least about 10 hours or more, and preferably longer
than any other limiting factor in the advancement of a borehole. In
this way using the LBHA of the present invention could reduce
tripping activities to only those that are related to casing and
completion activities, greatly reducing the cost for drilling the
well.
[0053] By way of example, and without limitation to other spot and
beam parameters and combinations thereof, the LBHA and optics
should be capable of creating and maintain the laser beam
parameters set out in Table 1 in deep downhole environments.
TABLE-US-00001 TABLE 1 Exam- ple Laser Beam Parameters 1 Beam Spot
Size 0.3585'', (0.0625'', (12.5 mm-0.5 mm), 0.1'', (circular or
(elliptical)) Exposure Times 0.05 s, 0.1 s, 0.2 s, 0.5 s, 1 s
Time-average 0.25 kW, 0.5 kW, 1.6 kW, 3 kW, 5 kW Power 2 Beam Type
CW/Collimated Beam Spot Size 0.0625'' (12.5 mm .times. 0.5 mm),
0.1'' (circular or (elliptical)) Power 0.25 kW, 0.5 kW, 1.6 kW, 3
kW, 5 kW 3 Beam Type CW/Collimated and Pulsed at Spallation Zones
Specific Power Spallation zones (920 W/cm2 at ~2.6 kJ/cc for
Sandstone &4 kW/cm2 at ~0.52 kJ/cc for Limestone) Beam Size
12.5 mm .times. 0.5 mm 4 Beam Type CW/Collimated or Pulsed
atSpallation Zones Specific Power Spallation zones (~920 W/cm2 at
~2.6 kJ/cc for Sandstone &4 kW/cm2 at ~0.52 kJ/cc for
Limestone) Beam Size 12.5 mm .times. 0.5 mm 5 Beam Type
CW/Collimated or Pulsed at Spallation Zones Specific Power
Spallation zones {~920 W/cm2 at -2.6 kJ/cc for Sandstone &4
kW/cm2 at ~0.52 kJ/cc for Limestone) Beam Size 12.5 mm .times. 0.5
mm 6 Beam Type CW/Collimated or Pulsed at Spallation Zones Specific
Power illumination zones {~10,000 W/cm2 at -1 kJ/cc for Sandstone
& 10,000 W/cm2 at ~5 kJ/cc for Limestone) Beam Size 50 mm
.times. 10 mm; 50 mm .times. 0.5 mm; 150 mm .times. 0.5 mm
[0054] In general, the energy distribution of the laser beam when
it illuminates the material in the borehole to be removed, such as
rock or casing, is important to maximizing the efficiency and rate
of removal of material and the advancement of the borehole. The
most desirable beam energy distribution is dependent upon, among
other facts, the downhole conditions, the beam profile at the
bottom of the borehole, the spot shape and whether the spot is
rotated, scanned, fixed or a combination of these. Thus, various
optical systems and combination of optics are provide herein to
take a particular laser beam profile from the downhole end of a
fiber and provided a desired output and energy profile on the
borehole surface.
[0055] In FIGS. 1A and 1B, there is provided a graphic
representation of an example of a laser beam--borehole surface
interaction. Thus, there is shown a laser beam 1000, an area of
beam illumination 1001, i.e., a spot (as used herein unless
expressly provided otherwise the term "spot" is not limited to a
circle), on a borehole wall or bottom 1002. There is further
provided in FIG. 1B a more detailed representation of the
interaction and a corresponding chart 1010 categorizing the stress
created in the area of illumination. Chart 1010 provides von Mises
Stress in .sigma..sub.M 10.sup.8 N/m.sup.2 wherein the cross
hatching and shading correspond to the stress that is created in
the illuminated area for a 30 mill-second illumination period,
under down hole conditions of 2000 psi and a temperature of 150F,
with a beam having a fluence of 2 kW/cm.sup.2. Under these
conditions the compressive strength of basalt is about
2.6.times.10.sup.8 N/m.sup.2, and the cohesive strength is about
0.66.times.10.sup.8 N/m.sup.2. Thus, there is shown a first area
1005 of relative high stress, from about 4.722 to
5.211.times.10.sup.8 N/m.sup.2, a second area 1006 of relative
stress at or exceeding the compressive stress of basalt under the
downhole conditions, from about 2.766 to 3.255.times.10.sup.8
N/m.sup.2, a third area 1007 of relative stress about equal to the
compressive stress of basalt under the downhole conditions, from
about 2.276 to 2.766.times.10.sup.8 N/m.sup.2, a fourth area 1008
of relative lower stress that is below the compressive stress of
basalt under the downhole conditions yet greater than the cohesive
strength, from about 2.276 to 2.766.times.10.sup.8 N/m.sup.2, and a
fifth area 1009 of relative stress that is at or about the cohesive
strength of basalt under the downhole conditions, from about 0.320
to 0.899.times.10.sup.8 N/m.sup.2.
[0056] Accordingly, the profiles of the beam interaction with the
borehole to obtain a maximum amount of stress in the borehole in an
efficient manner, and thus, increase the rate of advancement of the
borehole can be obtained. Thus, for example if an elliptical spot
is rotated about its center point for a beam that is either uniform
or Gaussian the energy deposition profile is illustrated in FIGS.
2A and 2B. Where the area of the borehole from the center point of
the beam is shown as x and y axes 2001 and 2002 and the amount of
energy deposited is shown on the z axis 2003. From this it is seen
that inefficiencies are present in the deposition of energy to the
borehole, with the outer sections of the borehole 2005 and 2006
being the limiting factor in the rate of advancement.
[0057] Thus, it is desirable to modify the beam deposition profile
to obtain a substantially even and uniform deposition profile upon
rotation of the beam. An example of such a preferred beam
deposition profile is provided in FIGS. 3A and 3B, where FIG. 3A
shows the energy deposition profile with no rotation, and FIG. 3B
shows the energy deposition profile when the beam profile of 3A is
rotated through one rotation, i.e., 360 degrees; having x and y
axes 3001 and 3002 and energy on z axis 3003. This energy
deposition distribution would be considered substantially
uniform.
[0058] To obtain this preferable beam energy profile there are
provided examples of optical assemblies that may be used with a
LBHA. Thus, Example 1 is illustrated in FIGS. 4A to 4D, having x
and y axes 4001 and 4002 and z axis 4003, wherein there is provided
a laser beam 4005 having a plurality of rays 4007. The laser beam
4005 enters an optical assembly 4020, having a collimating lens
4009, having input curvature 4011 and an output curvature 4013.
There is further provided an axicon lens 4015 and a window 4017.
The optical assembly of Example 1 would provide a desired beam
intensity profile from an input beam having a substantially
Gaussian, Gaussian, or super-Gaussian distribution for applying the
beam spot to a borehole surface 4030.
[0059] Example 2 is illustrated in FIG. 5 and has an optical
assembly 5020 for providing the desired beam intensity profile of
FIG. 3A and energy deposition of FIG. 3B to a borehole surface from
a laser beam having a uniform distribution. Thus, there is provided
in Example 2 a laser beam 5005 having a uniform profile and rays
5007, that enters a spherical lens 5013, which collimates the
output of the laser from the downhole end of the fiber, the beam
then exits 5013 and enters a toroidal lens 5015, which has power in
the x-axis to form the minor-axis of the elliptical beam. The beam
then exits 5015 and enters a pair of aspherical toroidal lens 5017,
which has power in the y-axis to map the y-axis intensity profiles
form the pupil plane to the image plane. The beam then exits the
lens 5017 and enters flat window 5019, which protects the optics
from the outside environment.
[0060] Example 3 is illustrated in FIG. 6, which provides a further
optical assembly for providing predetermined beam energy profiles.
Thus, there is provided a laser beam 6005 having rays 6007, which
enters collimating lens 6009, spot shape forming lens 6011, which
is preferably an ellipse, and a micro optic array 6013. The micro
optic array 6013 may be a micro-prism array, or a micro lens array.
Further the micro optic array may be specifically designed to
provide a predetermined energy deposition profile, such as the
profile of FIG. 3.
[0061] Example 4 is illustrated in FIG. 7, which provides an
optical assembly for providing a predetermined beam pattern. Thus,
there is provided a laser beam 7005, exiting the downhole end of
fiber 7040, having rays 6007, which enters collimating lens 6009, a
diffractive optic 7011, which could be a micro optic, or a
corrective optic to a micro optic, that provides pattern 7020,
which may but not necessary pass through reimaging lens 7013, which
provides pattern 7021.
[0062] There is further provided shot patterns for illuminating a
borehole surface with a plurality of spots in a multi-rotating
pattern. Accordingly in FIG. 8 there is provided a first pair of
spots 8003, 8005, which illuminate the bottom surface 8001 of the
borehole. The first pair of spots rotate about a first axis of
rotation 8002 in the direction of rotation shown by arrow 8004 (the
opposite direction of rotation is also contemplated herein). There
is provided a second pair of spots 8007, 8009, which illuminate the
bottom surface 8001 of the borehole. The second pair of shots
rotate about axis 8006 in the direction of rotation shown by arrow
8008 (the opposite direction of rotation is also contemplated
herein). The distance between the spots in each pair of spots may
be the same or different. The first and second axis of rotation
simultaneously rotate around the center of the borehole 8012 in a
rotational direction, shown by arrows 8012, that is preferably in
counter-rotation to the direction of rotation 8008, 8004. Thus,
preferably although not necessarily, if 8008 and 8004 are
clockwise, then 8012 should be counter-clockwise. This shot pattern
provides for a substantially uniform energy deposition.
[0063] There is illustrated in FIG. 9 an elliptical shot pattern of
the general type discussed with respect to Examples 1 to 3 having a
center 9001, a major axis 9002, a minor axis 9003 and is rotated
about the center. In this way the major axis of the spot would
generally correspond to the diameter of the borehole, ranging from
any known or contemplated diameters such as about 30, 20, 171/2,
133/8, 121/4, 95/8, 81/2, 7, and 61/4 inches.
[0064] There is further illustrated in FIG. 10 a rectangular shaped
spot 1001 that would be rotated around the center of the borehole.
There is illustrated in FIG. 11 a pattern 1101 that has a plurality
of individual shots 1102 that may be rotated, scanned or moved with
respect to the borehole to provide the desired energy deposition
profile. The is further illustrated in FIG. 12 a squared shot 1201
that is scanned 1201 in a raster scan matter along the bottom of
the borehole, further a circle, square or other shape shot may be
scanned.
[0065] The LBHA, by way of example, may include one or more optical
manipulators. An optical manipulator may generally control a laser
beam, such as by directing or positioning the laser beam to remove
material, such as rock. In some configurations, an optical
manipulator may strategically guide a laser beam to remove
material, such as rock. For example, spatial distance from a
borehole wall or rock may be controlled, as well as impact angle.
In some configurations, one or more steerable optical manipulators
may control the direction and spatial width of the one or more
laser beams by one or more reflective mirrors or crystal
reflectors. In other configurations, the optical manipulator can be
steered by, but steering means not being limited to, an
electro-optic switch, electroactive polymers, galvonometers,
piezoelectrics, rotary/linear motors, and/or active-phase control
of an array of sources for electronic beam steering. In at least
one configuration, an infrared diode laser or fiber laser optical
head may generally rotate about a vertical axis to increase
aperture contact length. Various programmable values such as
specific energy, specific power, pulse rate, duration and the like
may be implemented as a function of time. Thus, where to apply
energy may be strategically determined, programmed and executed so
as to enhance a rate of penetration, the efficiency of borehole
advancement, and/or laser/rock interaction. One or more algorithms
may be used to control the optical manipulator.
[0066] The LBHA and optics, in at least one aspect, provide that a
beam spot pattern and continuous beam shape may be formed by a
refractive, reflective, diffractive or transmissive grating optical
element. refractive, reflective, diffractive or transmissive
grating optical elements may be made, but are not limited to being
made, of fused silica, quartz, ZnSe, Si, GaAs, polished metal,
sapphire, and/or diamond. These may be, but are not limited to
being, optically coated with the said materials to reduce or
enhance the reflectivity.
[0067] In accordance with one or more aspects, one or more fiber
optic distal fiber ends may be arranged in a pattern. The
multiplexed beam shape may comprise a cross, an x shape, a
viewfinder, a rectangle, a hexagon, lines in an array, or a related
shape where lines, squares, and cylinders are connected or spaced
at different distances.
[0068] In accordance with one or more aspects, one or more
refractive lenses, diffractive elements, transmissive gratings,
and/or reflective lenses may be added to focus, scan, and/or change
the beam spot pattern from the beam spots emitting from the fiber
optics that are positioned in a pattern. One or more refractive
lenses, diffractive elements, transmissive gratings, and/or
reflective lenses may be added to focus, scan, and/or change the
one or more continuous beam shapes from the light emitted from the
beam shaping optics. A collimator may be positioned after the beam
spot shaper lens in the transversing optical path plane. The
collimator may be an aspheric lens, spherical lens system composed
of a convex lens, thick convex lens, negative meniscus, and
bi-convex lens, gradient refractive lens with an aspheric profile
and achromatic doublets. The collimator may be made of the said
materials, fused silica, ZnSe, SF glass, or a related material. The
collimator may be coated to reduce or enhance reflectivity or
transmission. Said optical elements may be cooled by a purging
liquid or gas.
[0069] In some aspects, the one or more fiber optics with one or
more said optical elements and beam shaping optics may be steered
in the z-direction to keep the focal path constant and rotated by a
stepper motor, servo motors, piezoelectric motors, liquid or gas
actuator motor, and electro-optics switches. The z-axis may be
controlled by the drill string or mechanical standoff. The steering
may be mounted to one or more stepper rails, gantry's, gimbals,
hydraulic line, elevators, pistons, springs. The one or more fiber
optics with one or more fiber optics with one or more said beam
shaping optics and one or more collimator's may be rotated by a
stepper motor, servo motors, piezoelectric motors, liquid or gas
actuator motor, and electro-optic switch. The steering may be
mounted to one or more stepper rails, gantry's, gimbals, hydraulic
line, elevators, pistons, springs.
[0070] In some aspects, the fiber optics and said one or more
optical elements lenses and beam shaping optics may be encased in a
protective optical head made of, for example, the materials steel,
chrome-moly steel, steel cladded with hard-face materials such as
an alloy of chromium-nickel-cobalt, titanium, tungsten carbide,
diamond, sapphire, or other suitable materials known to those in
the art which may have a transmissive window cut out to emit the
light through the optical head.
[0071] In accordance with one or more aspects, a laser source may
be coupled to a plurality of optical fiber bundles with the distal
end of the fiber arranged to combine fibers together to form bundle
pairs, such that the power density through one fiber bundle pair is
within the material removal zone and one or more beam spots
illuminate the material, such as rock with the bundle pairs
arranged in a pattern to remove or displace the rock formation.
[0072] In accordance with one or more aspects, the pattern of the
bundle pairs may be spaced in such a way that the light from the
fiber bundle pairs emerge in one or more beam spot patterns that
comprise the geometry of a rectangular grid, a circle, a hexagon, a
cross, a star, a bowtie, a triangle, multiple lines in an array,
multiple lines spaced a distance apart non-linearly, an ellipse,
two or more lines at an angle, or a related shape. The pattern of
the bundle pairs may be spaced in such a way that the light from
the fiber bundles emerge as one or more continuous beam shapes that
comprise above geometries. A collimator may be positioned at a said
distance in the same plane below the distal end of the fiber bundle
pairs. One or more beam shaping optics may be positioned at a
distance in the same plane below the distal end of the fiber bundle
pairs. An optical element such as a non-axis-symmetric lens may be
positioned at a said distance in the same plane below the distal
end of the fiber bundle pairs. Said optical elements may be
positioned at an angle to the rock formation and rotated on an
axis.
[0073] In accordance with one or more aspects, the distal fiber end
made up of fiber bundle pairs may be steered in the X,Y,Z, planes
and rotationally using a stepper motor, servo motors, piezoelectric
motors, liquid or gas actuator motor. The distal fiber end may be
made up of fiber bundle pairs being steered with a collimator or
other optical element, which could be an objective, such as a
non-axis-symmetric optical element. The steering may be mounted to
one or more mechanical, hydraulic, or electro-mechanical element to
move the optical element. The distal end of fiber bundle pairs, and
optics may be protected as described above. The optical fibers may
be single-mode and/or multimode. The optical fiber bundles may be
composed of single-mode and/or multimode fibers.
[0074] In some aspects, the optical fibers may be entirely
constructed of glass, hollow core photonic crystals, and/or solid
core photonic crystals. The optical fibers may be jacketed with
materials such as, polyimide, acrylate, carbon polyamide, or
carbon/dual acrylate. Light may be sourced from a diode laser, disk
laser, chemical laser, fiber laser, or fiber optic source is
focused by one or more positive refractive lenses. Further,
examples of fibers useful for the transmission of high powered
laser energy over long distance in conjunction with the present
invention are provided in patent application Ser. No. 12/544,136
filed contemporaneously herewith the disclosure of which is
incorporated herein.
[0075] In at least one aspect, the positive refractive lens types
may include, a non-axis-symmetric optic such as a plano-convex
lens, a biconvex lens, a positive meniscus lens, or a gradient
refractive index lens with a plano-convex gradient profile, a
biconvex gradient profile, or positive meniscus gradient profile to
focus one or more beams spots to the rock formation. A positive
refractive lens may be comprised of the materials, fused silica,
sapphire, ZnSe, or diamond. Said refractive lens optical elements
can be steered in the light propagating plane to increase/decrease
the focal length. The light output from the fiber optic source may
originate from a plurality of one or more optical fiber bundle
pairs forming a beam shape or beam spot pattern and propagating the
light to the one or more positive refractive lenses.
[0076] It is readily understood in the art that the terms lens and
optic(al) elements, as used herein is used in its broadest terms
and thus may also refer to any optical elements with power, such as
reflective, transmissive or refractive elements,
[0077] In some aspects, the refractive positive lens may be a
microlens. The microlens can be steered in the light propagating
plane to increase/decrease the focal length as well as
perpendicular to the light propagating plane to translate the beam.
The microlens may receive incident light to focus to multiple foci
from one or more optical fibers, optical fiber bundle pairs, fiber
lasers, diode lasers; and receive and send light from one or more
collimators, positive refractive lenses, negative refractive
lenses, one or more mirrors, diffractive and reflective optical
beam expanders, and prisms.
[0078] In some aspects, a diffractive optical element beam splitter
could be used in conjunction with a refractive lens. The
diffractive optical element beam splitter may form double beam
spots or a pattern of beam spots comprising the shapes and patterns
set forth above.
[0079] In at least one aspect, the positive refractive lens may
focus the multiple beam spots to multiple foci. To remove or
displace the rock formation.
[0080] In accordance with one or more aspects, a collimator lens
may be positioned in the same plane and in front of a refractive or
reflective diffraction beam splitter to form a beam spot pattern or
beam shape; where a beam expander feeds the light into the
collimator. The optical elements may be positioned in the X,Y,Z
plane and rotated mechanically.
[0081] In accordance with one or more aspects, the laser beam spot
to the transversing mirror may be controlled by a beam expander.
The beam expander may expand the size of the beam and send the beam
to a collimator and then to a scanner of two mirrors positioning
the laser beam in the XY, YZ, or XZ axis. A beam expander may
expand the size of the beam and sends the beam to a collimator,
then to a diffractive or reflective optical element, and then to a
scanner of two mirrors positioning the laser beam in the XY, YZ, or
XZ axis. A beam expander may expand the size of the beam and send
the beam to a beam splitter attached behind a positive refractive
lens, that splits the beam and focuses is, to a scanner of two
mirrors positioning the laser beam in the XY, YZ, or XZ axis.
[0082] In some aspects, the material, such as a rock surface may be
imaged by a camera downhole. Data received by the camera may be
used to remove or displace the rock. Further spectroscopy may be
used to determine the rock morphology, which information may be
used to determine process parameters for removal of material.
[0083] In at least one aspect, a gas or liquid purge is employed.
The purge gas or liquid may remove or displace the cuttings, rock,
or other debris from the borehole. The fluid temperature may be
varied to enhance rock removal, and provide cooling.
[0084] In accordance with some embodiments, one or more beam
shaping optics may generate one or more beam spot lines, circles or
squares from the light emitted by one or more fiber optics or fiber
optic bundles. The beam shapes generated by a beam shaper may
comprise of being Gaussian, a circular top-hat ring, or line, or
rectangle, a polynomial towards the edge ring, or line, or
rectangle, a polynomial towards the center ring, or line, or
rectangle, a X or Y axis polynomial in a ring, or line, or
rectangle, or a asymmetric beam shape beams. One or more beam
shaping optics can be positioned in a pattern to form beam shapes.
In another embodiment, an optic can be positioned to refocus light
from one or more fiber optics or plurality of fiber optics. The
optic can be positioned after the beam spot shaper lens to increase
the working distance. In another embodiment, diffractive or
reflective optical element may be positioned in front of one or
more fiber optics or plurality of fiber optics. A positive
refractive lens may be added after the diffractive or reflective
optical element to focus the beam pattern or shape to multiple
foci.
[0085] Refractive optics that are useful and may be employed with
the present invention include but are not limited to: (i) negative
lenses, such as biconcave, plano-concave, negative meniscus, or a
gradient refractive index with a plano-concave profile, biconvex,
or negative meniscus; and, positive lenses such as one or more
positive refractive lens profiles may comprise of biconvex,
positive meniscus, or gradient refractive index lens with a
plano-convex gradient profile, a biconvex gradient profile, or
positive meniscus, such refractive lenses may be flat, cylindrical,
spherical, aspherical, or a molded shape. The refractive lens
material may be made of any desired material, such as fused silica,
ZnSe, sapphire, quartz or diamond.
[0086] One or more embodiments may generally include one or more
features to protect the optical element system and/or fiber laser
downhole. In accordance with one or more embodiments, reflective
and refractive lenses may include a cooling system, such as a fluid
jet associated with the optics.
[0087] In accordance with one or more embodiments, the one or more
lasers, fibers, or plurality of fiber bundles and the optical
element systems to generate one or more beam spots, shape, or
patterns from the above light emitting sources forming an optical
head may be protected from downhole pressure and environments by
being encased in an appropriate material. Such materials may
include steel, titanium, diamond, tungsten carbide, composites and
the like as well as the other materials provided herein and known
to those skilled in the art. A transmissive window may be made of a
material that can withstand the downhole environment, while
retaining transmissive qualities. One such material may be sapphire
or other materials with similar qualities. An optical head may be
entirely encased by sapphire. In at least one embodiment, the
optical head may be made of diamond, tungsten carbide, steel, and
titanium other than part where the laser beam is emitted.
[0088] In accordance with one or more embodiments, the fiber optics
forming a pattern can send any desired amount of power. In some
non-limiting embodiments, fiber optics may send up to 10 kW or more
per a fiber. The fibers may transmit any desired wavelength. In
some embodiments, the range of wavelengths the fiber can transmit
may preferably be between about 800 nm and 2100 nm. The fiber can
be connected by a connector to another fiber to maintain the proper
fixed distance between one fiber and neighboring fibers. For
example, fibers can be connected such that the beam spot from
neighboring optical fibers when irradiating the material, such as a
rock surface are non-overlapping to the particular optical fiber.
The fiber may have any desired core size. In some embodiments, the
core size may range from about 50 microns to 600 microns. The fiber
can be single mode or multimode. If multimode, the numerical
aperture of some embodiments may range from 0.1 to 0.6. A lower
numerical aperture may be preferred for beam quality, and a higher
numerical aperture may be easier to transmit higher powers with
lower interface losses. In some embodiments, a fiber laser emitted
light at wavelengths comprised of 1060 nm to 1080 nm, 1530 nm to
1600 nm, 1800 nm to 2100 nm, diode lasers from 400 nm to 1600 nm,
CO.sub.2 Laser at 110,600 nm, or Nd:YAG Laser emitting at 1064 nm
can couple to the optical fibers. In some embodiments, the fiber
can have a low water content. The fiber can be jacketed, such as
with polyimide, acrylate, carbon polyamide, and carbon/dual
acrylate or other material. If requiring high temperatures, a
polyimide or a derivative material may be used to operate at
temperatures over 300 degrees Celsius. By way of example, the
fibers may be a fused silica step index fiber, a hollow core fiber,
such as a hollow core photonic crystal, or solid core fiber, such
as a solid core photonic crystal, or combinations of these. In some
embodiments, using hollow core photonic crystal fibers at
wavelengths of 1500 nm or higher may minimize absorption
losses.
[0089] The use of the plurality of optical fibers can be bundled
into a number of configurations to improve power density. The
optical fibers forming a bundle may range from two fibers at
hundreds of watts to kilowatt powers in each fiber to millions of
fibers at milliwatts or microwatts of power.
[0090] In accordance with one or more embodiments, one or more
diode lasers can be sent downhole with an optical element system to
form one or more beam spots, shapes, or patterns. In some
embodiments, more than one diode laser may couple to fiber optics,
where the fiber optics or a plurality of fiber optic bundles form a
pattern of beam spots irradiating the material, such as a rock
surface.
[0091] Thus, by way of example, an LBHA that may employ the optical
assemblies of the present invention or provide a laser beam with
energy profiles of the present invention is illustrated in FIGS.
13A and B, which are collectively referred as FIG. 1. Thus, there
is provided a LBHA 1340, which has an upper part 1300 and a lower
part 1301. The upper part 1300 has housing 1318 and the lower part
1301 has housing 1319. The LBHA 1340, the upper part 1300, the
lower part 1301 and in particular the housings 1318, 1319 should be
constructed of materials and designed structurally to withstand the
extreme conditions of the deep downhole environment and protect any
of the components that are contained within them.
[0092] The upper part 1300 may be connected to the lower end of the
coiled tubing, drill pipe, or other means to lower and retrieve the
LBHA 1340 from the borehole. Further, it may be connected to
stabilizers, drill collars, or other types of downhole assemblies
(not shown in the figure), which in turn are connected to the lower
end of the coiled tubing, drill pipe, or other means to lower and
retrieve the LBHA 1340 from the borehole. The upper part 1300
further contains, is connect to, or otherwise optically associated
with the means 1302 that transmitted the high power laser beam down
the borehole so that the beam exits the lower end 1303 of the means
1302 and ultimately exist the LBHA 1340 to strike the intended
surface of the borehole. The beam path of the high power laser beam
is shown by arrow 1315. In FIG. 1 the means 1302 is shown as a
single optical fiber. The upper part 1300 may also have air
amplification nozzles 1305 that discharge the drilling fluid, for
example N.sub.2, to among other things assist in the removal of
cuttings up the borehole.
[0093] The upper part 1300 further is attached to, connected to or
otherwise associated with a means to provide rotational movement
1310. Such means, for example, would be a downhole motor, an
electric motor or a mud motor. The motor may be connected by way of
an axle, drive shaft, drive train, gear, or other such means to
transfer rotational motion 1311, to the lower part 1301 of the LBHA
1340. It is understood, as shown in the drawings for purposes of
illustrating the underlying apparatus, that a housing or protective
cowling may be placed over the drive means or otherwise associated
with it and the motor to protect it form debris and harsh downhole
conditions. In this manner the motor would enable the lower part
1301 of the LBHA 1340 to rotate. An example of a mud motor is the
CAVO 1.7'' diameter mud motor. This motor is about 7 ft long and
has the following specifications: 7 horsepower @ 110 ft-lbs full
torque; motor speed 0-700 rpm; motor can run on mud, air, N.sub.2,
mist, or foam; 180 SCFM, 500-800 psig drop; support equipment
extends length to 12 ft; 10:1 gear ratio provides 0-70 rpm
capability; and has the capability to rotate the lower part 1301 of
the LBHA through potential stall conditions.
[0094] The upper part 1300 of the LBHA 1340 is joined to the lower
part 1301 with a sealed chamber 1304 that is transparent to the
laser beam and forms a pupil plane 1320 to permit unobstructed
transmission of the laser beam to the beam shaping optics 1306 in
the lower part 1301. The lower part 1301 is designed to rotate. The
sealed chamber 1304 is in fluid communication with the lower
chamber 1301 through port 1314. Port 1314 may be a one way valve
that permits clean transmissive fluid and preferably gas to flow
from the upper part 1300 to the lower part 1301, but does not
permit reverse flow, or if may be another type of pressure and/or
flow regulating value that meets the particular requirements of
desired flow and distribution of fluid in the downhole environment.
Thus, for example there is provided in FIG. 1 a first fluid flow
path, shown by arrows 1316, and a second fluid flow path, shown by
arrows 1317. In the example of FIG. 13 the second fluid flow path
is a laminar flow, however, other non-laminar flows and low
turbulent flows are permissible.
[0095] The lower part 1301 has a means for receiving rotational
force from the motor 1310, which in the example of the figure is a
gear 1312 located around the lower part housing 1319 and a drive
gear 1313 located at the lower end of the axle 1311. Other means
for transferring rotational power may be employed or the motor may
be positioned directly on the lower part. It being understood that
an equivalent apparatus may be employed which provide for the
rotation of the portion of the LBHA to facilitate rotation or
movement of the laser beam spot while that the same time not
providing undue rotation, or twisting forces, to the optical fiber
or other means transmitting the high power laser beam down the hole
to the LBHA. In his way laser beam spot can be rotated around the
bottom of the borehole. The lower part 1301 has a laminar flow
outlet 1307 for the fluid to exit the LBHA 1300, and two hardened
rollers 1308, 1309 at its lower end.
[0096] The two hardened rollers may be made of a stainless steel or
a steel with a hard face coating such as tungsten carbide,
chromium-cobalt-nickel alloy, or other similar materials. They may
also contain a means for mechanically cutting rock that has been
thermally degraded by the laser. They may range in length from
about 1 in to about 4 inches and preferably are about 2-3 inches
and may be as large as or larger than 6 inches. (Length as used
herein refers to the longest dimenstion of the roller.) Moreover in
LBHAs for drilling larger diameter boreholes they may be in the
range of 6 to 10-20 to 30 inches in diameter.
[0097] Thus, FIG. 13 provides for a high power laser beam path 1315
that enters the LBHA 1340, travels through beam spot shaping optics
1306, and then exits the LBHA to strike its intended target on the
surface of a borehole. Further, although it is not required, the
beam spot shaping optics may also provide a rotational element to
the spot, and if so, would be considered to be beam rotational and
shaping spot optics.
[0098] In use the high energy laser beam, for example greater than
15 kW, would enter the LBHA 1300, travel down fiber 1302, exit the
end of the fiber 1303 and travel through the sealed chamber 1304
and pupil plane 1320 into the optics 1306, where it would be shaped
and focused into a spot, the optics 1306 would further rotate the
spot. The laser beam would then illuminate, in a potentially
rotating manner, the bottom of the borehole spalling, chipping
melting and/or vaporizing the rock and earth illuminated and thus
advance the borehole. The lower part would be rotating and this
rotation would further cause the rollers 1308, 1309 to physically
dislodge any material that was effected by the laser or otherwise
sufficiently fixed to not be able to be removed by the flow of the
drilling fluid alone.
[0099] The cuttings would be cleared from the laser path by the
flow of the fluid along the path 1317, as well as, by the action of
the rollers 2008, 2009 and the cuttings would then be carried up
the borehole by the action of the drilling fluid from the air
amplifiers 1305, as well as, the laminar flow opening 1307.
[0100] It is understood that the configuration of the LBHA is FIG.
13 is by way of example and that other configurations of its
components are available to accomplish the same results. Thus, the
motor may be located in the lower part rather than the upper part,
the motor may be located in the upper part but only turn the optics
in the lower part and not the housing. The optics may further be
located in both the upper and lower parts, which the optics for
rotation being positioned in that part which rotates. The motor may
be located in the lower part but only rotate the optics and the
rollers. In this later configuration the upper and lower parts
could be the same, i.e., there would only be one part to the LBHA.
Thus, for example the inner portion of the LBHA may rotate while
the outer portion is stationary or vice versa, similarly the top
and/or bottom portions may rotate or various combinations of
rotating and non-rotating components may be employed, to provide
for a means for the laser beam spot to be moved around the bottom
of the borehole.
[0101] In general, and by way of further example, the LBHA may
comprise a housing, which may by way of example, be made up of
sub-housings. These sub-housings may be integral, they may be
separable, they may be removably fixedly connected, they may be
rotatable, or there may be any combination of one or more of these
types of relationships between the sub-housings. The LBHA may be
connected to the lower end of the coiled tubing, drill pipe, or
other means to lower and retrieve the LBHA from the borehole.
Further, it may be connected to stabilizers, drill collars, or
other types of downhole assemblies, which in turn are connected to
the lower end of the coiled tubing, drill pipe, or other means to
lower and retrieve the bottom hole assembly from the borehole. The
LBHA has associated therewith a means that transmitted the high
power energy from down the borehole.
[0102] The LBHA may also have associated with, or in, it means to
handle and deliver drilling fluids. These means may be associated
with some or all of the sub-housings. There are further provided
mechanical scraping means, e.g. a PDC bit, to remove and/or direct
material in the borehole, although other types of known bits and/or
mechanical drilling heads by also be employed in conjunction with
the laser beam. These scrapers or bits may be mechanically
interacted with the surface or parts of the borehole to loosen,
remove, scrap or manipulate such borehole material as needed. These
scrapers may be from less than about 1 inch to about 20 inches or
more in length. These types of mechanical means which may be
crushing, cutting, gouging scraping, grinding, pulverizing, and
shearing tools, or other tools used for mechanical removal of
material from a borehole, may be employed in conjunction with or
association with a LBHA. As used herein the "length" of such tools
refers to its longest dimension. In use the high energy laser beam,
for example greater than 15 kW, would travel down the fibers
through optics and then out the lower end of the LBHA to illuminate
the intended part of the borehole, or structure contained therein,
spalling, chipping, melting and/or vaporizing the material so
illuminated and thus advance the borehole or otherwise facilitating
the removal of the material so illuminated.
[0103] The optics 1306 should be selected to avoid or at least
minimize the loss of power as the laser beam travels through them.
The optics should further be designed to handle the extreme
conditions present in the downhole environment, at least to the
extent that those conditions are not mitigated by the housing 1319.
The optics may provide laser beam spots of differing power
distributions and shapes as set forth herein above. The optics may
further provide a single spot or multiple spots as set forth herein
above. Further examples and teaching of LBHAs are disclosed in
greater detail in co-pending U.S. patent application Ser. No.
12/544,038, and Ser. No. 12/543,968 filed contemporaneously
herewith, the disclosures of which are incorporate herein by
reference in their entirety.
[0104] In general, the output at the end of the fiber cable may
consist of one or many optical fibers. The beam shape at the rock
once determined can be created by either reimaging the fiber
(bundle), collimating the fiber (bundle) and then transforming it
to the Fourier plane to provide a homogeneous illumination of the
rock surface, or after collimation a diffractive optic, micro-optic
or axicon array could be used to create the beam patterned desired.
This beam pattern can be applied directly to the rock surface or
reimaged, or Fourier transformed to the rock surface to achieve the
desired pattern. The processing head may include a dichroic
splitter to allow the integration of a camera or a fiber optic
imaging system monitoring system into the processing head to allow
progress to be monitored and problem to be diagnosed.
[0105] Drilling may be conducted in a dry environment or a wet
environment. An important factor is that the path from the laser to
the rock surface should be kept as clear as practical of debris and
dust particles or other material that would interfere with the
delivery of the laser beam to the rock surface. The use of high
brightness lasers provides another advantage at the process head,
where long standoff distances from the last optic to the work piece
are important to keeping the high pressure optical window clean and
intact through the drilling process. The beam can either be
positioned statically or moved mechanically, opto-mechanically,
electro-optically, electromechanically, or any combination of the
above to illuminate the earth region of interest.
[0106] Thus, in general, and by way of example, there is provided
in FIG. 14 a high efficiency laser drilling system, including an
LBHA, which may use the optics of the present invention and which
may employ the laser shot patterns, and energy deposition profiles
of the present invention. Such systems are disclosed in greater
detail in co-pending U.S. patent application Ser. No. 12/544,136,
filed contemporaneously herewith, the disclosure of which is
incorporate herein by reference in its entirety.
[0107] Thus, in general, and by way of example, there is provided
in FIG. 14 a high efficiency laser drilling system 1400 for
creating a borehole 1401 in the earth 1402. As used herein the term
"earth" should be given its broadest possible meaning (unless
expressly stated otherwise) and would include, without limitation,
the ground, all natural materials, such as rocks, and artificial
materials, such as concrete, that are or may be found in the
ground, including without limitation rock layer formations, such
as, granite, basalt, sandstone, dolomite, sand, salt, limestone,
rhyolite, quartzite and shale rock.
[0108] FIG. 14 provides a cut away perspective view showing the
surface of the earth 1430 and a cut away of the earth below the
surface 1402. In general and by way of example, there is provided a
source of electrical power 1403, which provides electrical power by
cables 1404 and 1405 to a laser 1406 and a chiller 1407 for the
laser 1406. The laser provides a laser beam, i.e., laser energy,
that can be conveyed by a laser beam transmission means 1408 to a
spool of coiled tubing 1409. A source of fluid 1410 is provided.
The fluid is conveyed by fluid conveyance means 1411 to the spool
of coiled tubing 1409.
[0109] The spool of coiled tubing 1409 is rotated to advance and
retract the coiled tubing 1412. Thus, the laser beam transmission
means 1408 and the fluid conveyance means 1411 are attached to the
spool of coiled tubing 1409 by means of rotating coupling means
1413. The coiled tubing 1412 contains a means to transmit the laser
beam along the entire length of the coiled tubing, i.e., "long
distance high power laser beam transmission means," to the bottom
hole assembly, 1414. The coiled tubing 1412 also contains a means
to convey the fluid along the entire length of the coiled tubing
1412 to the bottom hole assembly 1414.
[0110] Additionally, there is provided a support structure 1415,
which for example could be derrick, crane, mast, tripod, or other
similar type of structure. The support structure holds an injector
1416, to facilitate movement of the coiled tubing 1412 in the
borehole 1401. As the borehole is advance to greater depths from
the surface 1430, the use of a diverter 1417, a blow out preventer
(BOP) 1418, and a fluid and/or cutting handling system 1419 may
become necessary. The coiled tubing 1412 is passed from the
injector 1416 through the diverter 1417, the BOP 1418, a wellhead
1420 and into the borehole 1401.
[0111] The fluid is conveyed to the bottom 1421 of the borehole
1401. At that point the fluid exits at or near the bottom hole
assembly 1414 and is used, among other things, to carry the
cuttings, which are created from advancing a borehole, back up and
out of the borehole. Thus, the diverter 1417 directs the fluid as
it returns carrying the cuttings to the fluid and/or cuttings
handling system 1419 through connector 1422. This handling system
1419 is intended to prevent waste products from escaping into the
environment and either vents the fluid to the air, if permissible
environmentally and economically, as would be the case if the fluid
was nitrogen, returns the cleaned fluid to the source of fluid
1410, or otherwise contains the used fluid for later treatment
and/or disposal.
[0112] The BOP 1418 serves to provide multiple levels of emergency
shut off and/or containment of the borehole should a high-pressure
event occur in the borehole, such as a potential blow-out of the
well. The BOP is affixed to the wellhead 1420. The wellhead in turn
may be attached to casing. For the purposes of simplification the
structural components of a borehole such as casing, hangers, and
cement are not shown. It is understood that these components may be
used and will vary based upon the depth, type, and geology of the
borehole, as well as, other factors.
[0113] The downhole end 1423 of the coiled tubing 1412 is connect
to the bottom hole assembly 1414. The bottom hole assemble 1414
contains optics for delivering the laser beam 1424 to its intended
target, in the case of FIG. 4, the bottom 1421 of the borehole
1401. The bottom hole assemble 1414, for example, also contains
means for delivering the fluid.
[0114] Thus, in general this system operates to create and/or
advance a borehole by having the laser create laser energy in the
form of a laser beam. The laser beam is then transmitted from the
laser through the spool and into the coiled tubing. At which point,
the laser beam is then transmitted to the bottom hole assembly
where it is directed toward the surfaces of the earth and/or
borehole. Upon contacting the surface of the earth and/or borehole
the laser beam has sufficient power to cut, or otherwise effect,
the rock and earth creating and/or advancing the borehole. The
laser beam at the point of contact has sufficient power and is
directed to the rock and earth in such a manner that it is capable
of borehole creation that is comparable to or superior to a
conventional mechanical drilling operation. Depending upon the type
of earth and rock and the properties of the laser beam this cutting
occurs through spalling, thermal dissociation, melting,
vaporization and combinations of these phenomena.
[0115] Although not being bound by the present theory, it is
presently believed that the laser material interaction entails the
interaction of the laser and a fluid or media to clear the area of
laser illumination. Thus the laser illumination creates a surface
event and the fluid impinging on the surface rapidly transports the
debris, i.e. cuttings and waste, out of the illumination region.
The fluid is further believed to remove heat either on the macro or
micro scale from the area of illumination, the area of
post-illumination, as well as the borehole, or other media being
cut, such as in the case of perforation.
[0116] The fluid then carries the cuttings up and out of the
borehole. As the borehole is advanced the coiled tubing is
unspooled and lowered further into the borehole. In this way the
appropriate distance between the bottom hole assembly and the
bottom of the borehole can be maintained. If the bottom hole
assembly needs to be removed from the borehole, for example to case
the well, the spool is wound up, resulting in the coiled tubing
being pulled from the borehole. Additionally, the laser beam may be
directed by the bottom hole assembly or other laser directing tool
that is placed down the borehole to perform operations such as
perforating, controlled perforating, cutting of casing, and removal
of plugs. This system may be mounted on readily mobile trailers or
trucks, because its size and weight are substantially less than
conventional mechanical rigs.
[0117] There is provided by way of examples illustrative and
simplified plans of potential drilling scenarios using the laser
drilling systems and apparatus of the present invention.
Drilling Plan Example 1
TABLE-US-00002 [0118] Drilling type/Laser Depth Rock type power
down hole Drill 171/2 Surface- Sand and Conventional inch hole 3000
ft shale mechanical drilling Run 133/8 Length inch casing 3000 ft
Drill 121/4 3000 ft- basalt 40 kW inch hole 8,000 ft (minimum) Run
95/8 Length inch casing 8,000 ft Drill 81/2 8,000 ft- limestone
Conventional inch hole 11,000 ft mechanical drilling Run 7 inch
Length casing 11,000 ft Drill 61/4 11,000 ft- Sand stone
Conventional inch hole 14,000 ft mechanical drilling Run 5 inch
Length liner 3000 ft
Drilling Plan Example 2
TABLE-US-00003 [0119] Drilling type/Laser Depth Rock type power
down hole Drill 171/2 Surface- Sand and Conventional inch hole 500
ft shale mechanical drilling Run 133/8 Length casing 500 ft Drill
121/4 500 ft- granite 40 kW hole 4,000 ft (minimum) Run 95/8 Length
inch casing 4,000 ft Drill 81/2 4,000 ft- basalt 20 kW inch hole
11,000 ft (mimimum) Run 7 inch Length casing 11,000 ft Drill 61/4
11,000 ft- Sand stone Conventional inch hole 14,000 ft mechanical
drilling Run 5 inch Length liner 3000 ft
[0120] In accordance with one or more aspects, a method for laser
drilling using an optical pattern to chip rock formations is
disclosed. The method may comprise irradiating the rock to spall,
melt, or vaporize with one or more lasing beam spots, beam spot
patterns and beam shapes at non-overlapping distances and timing
patterns to induce overlapping thermal rock fractures that cause
rock chipping of rock fragments. Single or multiple beam spots and
beam patterns and shapes may be formed by refractive and reflective
optics or fiber optics. The optical pattern, the pattern's timing,
and spatial distance between non-overlapping beam spots and beam
shapes may be controlled by the rock type thermal absorption at
specific wavelength, relaxation time to position the optics, and
interference from rock removal.
[0121] In some aspects, the lasing beam spot's power is either not
reduced, reduced moderately, or fully during relaxation time when
repositioning the beam spot on the rock surface. To chip the rock
formation, two lasing beam spots may scan the rock surface and be
separated by a fixed position of less than 2'' and non-overlapping
in some aspects. Each of the two beam spots may have a beam spot
area in the range between 0.1 cm.sup.2 and 25 cm.sup.2. The
relaxation times when moving the two lasing beam spots to their
next subsequent lasing locations on the rock surface may range
between 0.05 ms and 2 s. When moving the two lasing beam spots to
their next position, their power may either be not reduced, reduced
moderately, or fully during relaxation time.
[0122] In accordance with one or more aspects, a beam spot pattern
may comprise three or more beam spots in a grid pattern, a
rectangular grid pattern, a hexagonal grid pattern, lines in an
array pattern, a circular pattern, a triangular grid pattern, a
cross grid pattern, a star grid pattern, a swivel grid pattern, a
viewfinder grid pattern or a related geometrically shaped pattern.
In some aspects, each lasing beam spot in the beam spot pattern has
an area in the range of 0.1 cm.sup.2 and 25 cm.sup.2. To chip the
rock formation all the neighboring lasing beam spots to each lasing
beam spot in the beam spot pattern may be less than a fixed
position of 2'' and non-overlapping in one or more aspects.
[0123] In some aspects, more than one beam spot pattern to chip the
rock surface may be used. The relaxation times when positioning one
or more beam spot patterns to their next subsequent lasing location
may range between 0.05 ms and 2 s. The power of one or more beam
spot patterns may either be not reduced, reduced moderately, or
fully during relaxation time. A beam shape may be a continuous
optical beam spot forming a geometrical shape that comprises of, a
cross shape, hexagonal shape, a spiral shape, a circular shape, a
triangular shape, a star shape, a line shape, a rectangular shape,
or a related continuous beam spot shape.
[0124] In some aspects, positioning one line either linear or
non-linear to one or more neighboring lines either linear or
non-linear at a fixed distance less than 2'' and non-overlapping
may be used to chip the rock formation. Lasing the rock surface
with two or more beam shapes may be used to chip the rock
formation. The relaxation times when moving the one or more beam
spot shapes to their next subsequent lasing location may range
between 0.05 ms and 2 s.
[0125] In accordance with one or more aspects, the one or more
continuous beam shapes powers are either not reduced, reduced
moderately, or fully during relaxation time. The rock surface may
be irradiated by one or more lasing beam spot patterns together
with one or more beam spot shapes, or one or two beam spots with
one or more beam spot patterns. In some aspects, the maximum
diameter and circumference of one or more beam shapes and beam spot
patterns is the size of the borehole being chipped when drilling
the rock formation to well completion.
[0126] In accordance with one or more aspects, rock fractures may
be created to promote chipping away of rock segments for efficient
borehole drilling. In some aspects, beam spots, shapes, and
patterns may be used to create the rock fractures so as to enable
multiple rock segments to be chipped away. The rock fractures may
be strategically patterned. In at least some aspects, drilling rock
formations may comprise applying one or more non-overlapping beam
spots, shapes, or patterns to create the rock fractures. Selection
of one or more beam spots, shapes, and patterns may generally be
based on the intended application or desired operating parameters.
Average power, specific power, timing pattern, beam spot size,
exposure time, associated specific energy, and optical generator
elements may be considerations when selecting one or more beam
spots, a shape, or a pattern. The material to be drilled, such as
rock formation type, may also influence the one or more beam spot,
a shape, or a pattern selected to chip the rock formation. For
example, shale will absorb light and convert to heat at different
rates than sandstone.
[0127] In accordance with one or more aspects, rock may be
patterned with one or more beam spots. In at least one embodiment,
beam spots may be considered one or more beam spots moving from one
location to the next subsequent location lasing the rock surface in
a timing pattern. Beam spots may be spaced apart at any desired
distance. In some non-limiting aspects, the fixed position between
one beam spot and neighboring beam spots may be non-overlapping. In
at least one non-limiting embodiment, the distance between
neighboring beam spots may be less than 2''.
[0128] In accordance with one or more aspects, rock may be
patterned with one or more beam shapes. In some aspects, beam
shapes may be continuous optical shapes forming one or more
geometric patterns. A pattern may comprise the geometric shapes of
a line, cross, viewfinder, swivel, star, rectangle, hexagon,
circular, ellipse, squiggly line, or any other desired shape or
pattern. Elements of a beam shape may be spaced apart at any
desired distance. In some non-limiting aspects, the fixed position
between each line linear or non-linear and the neighboring lines
linear or non-linear are in a fixed position may be less than 2''
and non-overlapping.
[0129] In accordance with one or more aspects, rock may be
patterned with a beam pattern. Beam patterns may comprise a grid or
array of beam spots that may comprise the geometric patterns of
line, cross, viewfinder, swivel, star, rectangle, hexagon,
circular, ellipse, squiggly line. Beam spots of a beam pattern may
be spaced apart at any desired distance. In some non-limiting
aspects, the fixed position between each beam spot and the
neighboring beam spots in the beam spot pattern may be less than
2'' and non-overlapping.
[0130] In accordance with one or more aspects, the beam spot being
scanned may have any desired area. For example, in some
non-limiting aspects the area may be in a range between about 0.1
cm.sup.2 and about 25 cm.sup.2. The beam line, either linear or
non-linear, may have any desired specific diameter and any specific
and predetermined power distribution. For example, the specific
diameter of some non-limiting aspects may be in a range between
about 0.05 cm.sup.2 and about 25 cm.sup.2. In some non-limiting
aspects, the maximum length of a line, either linear or non-linear,
may generally be the diameter of a borehole to be drilled. Any
desired wavelength may be used. In some aspects, for example, the
wavelength of one or more beam spots, a shape, or pattern, may
range from 800 nm to 2000 nm. Combinations of one or more beam
spots, shapes, and patterns are possible and may be
implemented.
[0131] In accordance with one or more aspects, the timing patterns
and location to chip the rock may vary based on known rock chipping
speeds and/or rock removal systems. In one embodiment, relaxation
scanning times when positioning one or more beam spot patterns to
their next subsequent lasing location may range between 0.05 ms and
2 s. In another embodiment, a camera using fiber optics or
spectroscopy techniques can image the rock height to determine the
peak rock areas to be chipped. The timing pattern can be calibrated
to then chip the highest peaks of the rock surface to lowest or
peaks above a defined height using signal processing, software
recognition, and numeric control to the optical lens system. In
another embodiment, timing patterns can be defined by a rock
removal system. For example, if the fluid sweeps from the left side
the rock formation to the right side to clear the optical head and
raise the cuttings, the timing should be chipping the rock from
left to right to avoid rock removal interference to the one or more
beam spots, shape, or pattern lasing the rock formation or
vice-a-versa. For another example, if the rocks are cleared by a
jet nozzle of a gas or liquid, the rock at the center should be
chipped first and the direction of rock chipping should move then
away from the center. In some aspects, the speed of rock removal
will define the relaxation times.
[0132] In accordance with one or more aspects, the rock surface may
be affected by the gas or fluids used to clear the head and raise
the cuttings downhole. In one embodiment, heat from the optical
elements and losses from the fiber optics downhole or diode laser
can be used to increase the temperature of the borehole. This could
lower the required temperature to induce spallation making it
easier to spall rocks. In another embodiment, a liquid may saturate
the chipping location, in this situation the liquid would be turned
to steam and expand rapidly, this rapid expansion would thus create
thermal shocks improving the growth of fractures in the rock. In
another embodiment, an organic, volatile components, minerals or
other materials subject to rapid and differential heating from the
laser energy, may expand rapidly, this rapid expansion would thus
create thermal shocks improving the growth of fractures in the
rock. In another embodiment, the fluids of higher index of
refraction may be sandwiched between two streams of liquid with
lower index of refraction. The fluids used to clear the rock can
act as a wavelength to guide the light. A gas may be used with a
particular index of refraction lower than a fluid or another
gas.
[0133] By way of example and to further illustrate the teachings of
the present inventions, the thermal shocks can range from lasing
powers between one and another beam spot, shape, or pattern. In
some non-limiting aspects, the thermal shocks may reach 10
kW/cm.sup.2 of continuous lasing power density. In some
non-limiting aspects, the thermal shocks may reach up to 10
MW/cm.sup.2 of pulsed lasing power density, for instance, at 10
nanoseconds per pulse. In some aspects, two or more beam spots,
shapes, and patterns may have different power levels to thermally
shock the rock. In this way, a temperature gradient may be formed
between lasing of the rock surface.
[0134] By way of example and to further demonstrate the present
teachings of the inventions, there are provided examples of optical
heads, i.e., optical assemblies, and beam shot patterns, i.e.,
illumination patterns, that may be utilized with, as a part of, or
provided by an LBHA. FIG. 15 illustrates chipping a rock formation
using a lasing beam shape pattern. An optical beam 1501 shape
lasing pattern forming a checkerboard of lines 1502 irradiates the
rock surface 1503 of a rock 1504. The distance between the beam
spots shapes are non-overlapping because stress and heat absorption
cause natural rock fractures to overlap inducing chipping of rock
segments. These rock segments 1505 may peel or explode from the
rock formation.
[0135] By way of example and to further demonstrate the present
teachings, FIG. 16 illustrates removing rock segments by sweeping
liquid or gas flow 1601 when chipping a rock formation 1602. The
rock segments are chipped by a pattern 1606 of non-overlapping beam
spot shaped lines 1603, 1604, 1605. The optical head 1607,
optically associated with an optical fiber bundle, the optical head
1607 having an optical element system irradiates the rock surface
1608. A sweeping from left to right with gas or liquid flow 1601
raises the rock fragments 1609 chipped by the thermal shocks to the
surface.
[0136] By way of example and to further demonstrate the present
teachings, FIG. 17 illustrates removing rock segments by liquid or
gas flow directed from the optical head when chipping a rock
formation 1701. The rock segments are chipped by a pattern 1702 of
non-overlapping beam spot shaped lines 1703, 1704, 1705. The
optical head 1707 with an optical element system irradiates the
rock surface 1708. Rock segment debris 1709 is swept from a nozzle
1715 flowing a gas or liquid 1711 from the center of the rock
formation and away. The optical head 1707 is shown attached to a
rotating motor 1720 and fiber optics 1724 spaced in a pattern. The
optical head also has rails 1728 for z-axis motion if necessary to
focus. The optical refractive and reflective optical elements form
the beam path.
[0137] By way of example and to further demonstrate the present
teachings, FIG. 18 illustrates optical mirrors scanning a lasing
beam spot or shape to chip a rock formation in the XY-plane. Thus,
there is shown, with respect to a casing 1823 in a borehole, a
first motor of rotating 1801, a plurality of fiber optics in a
pattern 1803, a gimbal 1805, a second rotational motor 1807 and a
third rotational motor 1809. The second rotational motor 1807
having a stepper motor 1811 and a mirror 1815 associated therewith.
The third rotational motor 1809 having a stepper motor 1813 and a
mirror 1817 associated therewith. The optical elements 1819
optically associated with optical fibers 1803 and capable of
providing laser beam along optical path 1821. As the gimbal rotates
around the z-axis and repositions the mirrors in the XY-plane. The
mirrors are attached to a stepper motor to rotate stepper motors
and mirrors in the XY-plane. In this embodiment, fiber optics are
spaced in a pattern forming three beam spots manipulated by optical
elements that scan the rock formation a distance apart and
non-overlapping to cause rock chipping. Other fiber optic patterns,
shapes, or a diode laser can be used.
[0138] By way of example and to further demonstrate the present
teachings, FIG. 19 illustrates using a beam splitter lens to form
multiple beam foci to chip a rock formation. There is shown fibers
1901 in a pattern, a rail 1905 for providing z direction movement
shown by arrow 1903, a fiber connector 1907, an optical head 1909,
having a beam expander 1919, which comprises a DOE/ROE 1915, a
positive lens 1917, a collimator 1913, a beam expander 1911. This
assembly is capable of delivering one or more laser beams, as spots
1931 in a pattern, along optical paths 1929 to a rock formation
1923 having a surface 1925. Fiber optics are spaced a distance
apart in a pattern. An optical element system composed of a beam
expander and collimator feed a diffractive optical element attached
to a positive lens to focus multiple beam spots to multiple foci.
The distance between beam spots are non-overlapping and will cause
chipping. In this figure, rails move in the z-axis to focus the
optical path. The fibers are connected by a connector. Also, an
optical element can be attached to each fiber optic as shown in
this figure to more than one fiber optics.
[0139] By way of example and to further demonstrate the present
teachings, FIG. 20 illustrates using a beam spot shaper lens to
shape a pattern to chip a rock formation. There is provided an
array of optical fibers 2001, an optical head 2009. The optical
head having a rail 2003 for facilitating movement in the z
direction, shown by arrow 2005, a fiber connector 2007, an optics
assembly 2001 for shaping the laser beam that is transmitted by the
fibers 2001. The optical head capable of transmitting a laser beam
along optical path 2013 to illuminate a surface 2019 with a laser
beam shot pattern 2021 that has separate, but intersection lines in
a grid like pattern. Fiber optics are spaced a distance apart in a
pattern connected by a connector. The fiber optics emit a beam spot
to a beam spot shaper lens attached to the fiber optic. The beam
spot shaper lens forms a line in this figure overlapping to form a
tick-tack-toe laser pattern on the rock surface. The optical fiber
bundle wires are attached to rails moving in the z-axis to focus
the beam spots.
[0140] By way of example and to further demonstrate the present
teachings, FIG. 21 illustrates using a F-theta objective to focus a
laser beam pattern to a rock formation to cause chipping. There is
provided an optical head 2101, a first motor for providing rotation
2103, a plurality of optical fibers 2105, a connector 2107, which
positions the fibers in a predetermined pattern 2109. The laser
beam exits the fibers and travels along optical path 2111 through
F-Theta optics 2115 and illuminates rock surface 2113 in shot
pattern 2110. There is further shown rails 2117 for providing
z-direction movement. Fiber optics connected by connectors in a
pattern are rotated in the z-axis by a gimbal attached to the
optical casing head. The beam path is then refocused by an F-theta
objective to the rock formation. The beam spots are a distance
apart and non-overlapping to induce rock chipping in the rock
formation. A rail is attached to the optical fibers and F-theta
objective moving in the z-axis to focus the beam spot size.
[0141] It is understood that the rails in these examples for
providing z-direction movement are provided by way of illustration
and that z-direction movement, i.e. movement toward or away from
the bottom of the borehole may be obtained by other means, for
example winding and unwinding the spool or raising and lowering the
drill string that is used to advance the LBHA into or remove the
LBHA from the borehole.
[0142] By way of example and to further demonstrate the present
teachings, FIG. 22 illustrates mechanical control of fiber optics
attached to beam shaping optics to cause rock chipping. There is
provided a bundle of a plurality of fibers 2201 first motor 2205
for providing rotational movement a power cable 2203, an optical
head 2206, and rails 2207. There is further provided a second motor
2209, a fiber connector 2213 and a lens 2221 for each fiber to
shape the beam. The laser beams exit the fibers and travel along
optical paths 2215 and illumate the rock surface 2219 in a
plurality of individual line shaped shot patterns 2217. Fiber
optics are connected by connectors in a pattern and are attached to
a rotating gimbal motor around the z-axis. Rails are attached to
the motor moving in the z-axis. The rails are structurally attached
to the optical head casing and a support rail. A power cable powers
the motors. In this figure, the fiber optics emit a beam spot to a
beam spot shaper lens forming three non-overlapping lines to the
rock formation to induce rock chipping.
[0143] By way of example and to further demonstrate the present
teachings, FIG. 23 illustrates using a plurality of fiber optics to
form a beam shape line. There is provided an optical assembly 2311
having a source of laser energy 2301, a power cable 2303, a first
rotational motor 2305, which is mounted as a gimbal, a second motor
2307, and rails 2317 for z-direction movement. There is also
provided a plurality of fiber bundles 2321, with each bundle
containing a plurality of individual fibers 2323. The bundles 2321
are held in a predetermined position by connector 2325. Each bundle
2321 is optically associated with a beam shaping optics 2309. The
laser beams exit the beam shaping optics 2309 and travel along
optical path 2315 to illuminate surface 2319. The motors 2307, 2305
provide for the ability to move the plurality of beam spots in a
plurality of predetermined and desired patterns on the surface
2319, which may be the surface the borehole, such as the bottom
surface, side surface, or casing in the borehole. A plurality of
fiber optics are connected by connectors in a pattern and are
attached to a rotating gimbal motor around the z-axis. Rails are
attached to the motor moving in the z-axis. The rails are
structurally attached to the optical head casing and a support
rail. A power cable powers the motors. In this figure, the
plurality of fiber optics emits a beam spot to a beam spot shaper
lens forming three lines that are non-overlapping to the rock
formation. The beam shapes induce rock chipping.
[0144] By way of example and to further demonstrate the present
teachings, FIG. 24 illustrates using a plurality of fiber optics to
form multiple beam spot foci being rotated on an axis. There is
provided a laser source 2401, a first motor 2403, which is gimbal
mounted, a second motor 2405 and a means for z-direction movement
2407. There is further provided a plurality of fiber bundles 2413
and a connector 2409 for positioning the plurality of bundles 2413,
the laser beam exits the fibers and illuminates a surface in a
diverging and crossing laser shot pattern. The fiber optics are
connected by connectors at an angle being rotated by a motor
attached to a gimbal that is attached to a second motor moving in
the z-axis on rails. The motors receive power by a power cable. The
rails are attached to the optical casing head and support rail
beam. In this figure, a collimator sends the beam spot originating
from the plurality of optical fibers to a beam splitter. The beam
splitter is a diffractive optical element that is attached to
positive refractive lens. The beam splitter forms multiple beam
spot foci to the rock formation at non-overlapping distances to
chip the rock formation. The foci is repositioned in the z-axis by
the rails.
[0145] By way of example and to further demonstrate the present
teachings, FIG. 25 illustrates scanning the rock surface with a
beam pattern and XY scanner system. There is provided an optical
path 2501 for a laser beam, a scanner 2503, a diffractive optics
2505 and a collimator optics 2507. An optical fiber emits a beam
spot that is expanded by a beam expander unit and focused by a
collimator to a refractive optical element. The refractive optical
element is positioned in front of an XY scanner unit to form a beam
spot pattern or shape. The XY scanner composed of two mirrors
controlled by galvanometer mirrors 2509 irradiate the rock surface
2513 to induce chipping.
[0146] The novel and innovative apparatus of the present invention,
as set forth herein, may be used with conventional drilling rigs
and apparatus for drilling, completion and related and associated
operations. The apparatus and methods of the present invention may
be used with drilling rigs and equipment such as in exploration and
field development activities. Thus, they may be used with, by way
of example and without limitation, land based rigs, mobile land
based rigs, fixed tower rigs, barge rigs, drill ships, jack-up
platforms, and semi-submersible rigs. They may be used in
operations for advancing the well bore, finishing the well bore and
work over activities, including perforating the production casing.
They may further be used in window cutting and pipe cutting and in
any application where the delivery of the laser beam to a location,
apparatus or component that is located deep in the well bore may be
beneficial or useful.
[0147] From the foregoing description, one skilled in the art can
readily ascertain the essential characteristics of this invention,
and without departing from the spirit and scope thereof, can make
various changes and/or modifications of the invention to adapt it
to various usages and conditions.
* * * * *