U.S. patent application number 10/347066 was filed with the patent office on 2003-07-10 for flexible hose with thrusters for horizontal well drilling.
Invention is credited to Mazorow, Henry B..
Application Number | 20030127251 10/347066 |
Document ID | / |
Family ID | 26890676 |
Filed Date | 2003-07-10 |
United States Patent
Application |
20030127251 |
Kind Code |
A1 |
Mazorow, Henry B. |
July 10, 2003 |
Flexible hose with thrusters for horizontal well drilling
Abstract
A flexible hose assembly for horizontal well drilling is
provided. The flexible hose assembly has a number of spaced
thruster couplings along its length to impart drilling force to a
nozzle blaster at an end of the flexible hose. The thruster
couplings have rearwardly oriented thruster ports which impart a
forward drilling force upon exit of high pressure water through the
thruster ports. At least one of the thruster ports is an adjustable
thruster port having variable opening area, variable discharge
angle or both. The opening area and discharge angle can be adjusted
or controlled to regulate the amount of thrust imparted to the
flexible hose and the nozzle blaster, as well as to clear the bore
of debris and prevent its accumulation behind the nozzle blaster. A
method of horizontal well drilling using the above-described
flexible hose is also provided. The method is particularly useful
at shallow depths, such as 50-2000 feet.
Inventors: |
Mazorow, Henry B.; (Lorain,
OH) |
Correspondence
Address: |
PEARNE & GORDON LLP
526 SUPERIOR AVENUE EAST
SUITE 1200
CLEVELAND
OH
44114-1484
US
|
Family ID: |
26890676 |
Appl. No.: |
10/347066 |
Filed: |
January 17, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10347066 |
Jan 17, 2003 |
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09825329 |
Apr 3, 2001 |
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6530439 |
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60195076 |
Apr 6, 2000 |
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Current U.S.
Class: |
175/62 ;
175/424 |
Current CPC
Class: |
E21B 17/20 20130101;
E21B 7/18 20130101; E21B 4/00 20130101; E21B 7/065 20130101 |
Class at
Publication: |
175/62 ;
175/424 |
International
Class: |
E21B 007/18 |
Claims
What is claimed is:
1. A flexible hose assembly for horizontal well drilling comprising
a flexible hose, said flexible hose assembly having a proximal end
and a distal end, said proximal end being located rearward of said
distal end, said flexible hose having a plurality of thruster ports
disposed therein with at least one of said thruster ports being
disposed rearward of said distal end of said flexible hose
assembly, at least one of said thruster ports being adapted to
direct a jet of pressurized fluid in a direction such that a
centerline drawn through said jet forms an acute discharge angle
with the longitudinal axis of said flexible hose rearward from the
location of said thruster port, at least one of said thruster ports
being an adjustable thruster port.
2. A flexible hose assembly according to claim 1, said flexible
hose further comprising a plurality of flexible hose sections and
at least one thruster coupling, said thruster coupling being joined
to adjacent flexible hose sections, said adjustable thruster port
being disposed in said thruster coupling.
3. A flexible hose assembly according to claim 2, further
comprising a plurality of said thruster couplings, each thruster
coupling having at least one adjustable thruster port.
4. A flexible hose assembly according to claim 1, said hose
comprising flexible hydraulic hose rated to withstand at least
5,000 psi.
5. A flexible hose assembly according to claim 3, said thruster
couplings being spaced at least 10 feet apart from each other in
said hose.
6. A flexible hose assembly according to claim 3, each of said
thruster couplings comprising two threaded end sections and a
middle section, each of said end sections adapted to mate with a
pressure fitting attached to a section of said flexible hose.
7. A flexible hose assembly according to claim 1, said adjustable
thruster port having a variable opening area, said jet being
discharged from said thruster port through said opening.
8. A flexible hose assembly according to claim 1, said adjustable
thruster port having a variable discharge angle.
9. A flexible hose assembly according to claim 7, said adjustable
thruster port comprising a shutter for regulating the area of said
opening of said thruster port.
10. A flexible hose assembly according to claim 9, said shutter
being an iris.
11. A flexible hose assembly according to claim 9, further
comprising a servo controller for actuating said shutter to thereby
regulate said opening area of said adjustable thruster port.
12. A flexible hose assembly according to claim 11, said servo
controller being controlled via wireline or radio signal.
13. A flexible hose assembly according to claim 2, said thruster
coupling comprising 2-8 thruster ports evenly spaced around the
circumference of said thruster coupling.
14. A flexible hose assembly according to claim 8, said adjustable
thruster port comprising a servo-controlled pivot arm, said pivot
arm being adjustable to regulate said discharge angle.
15. A flexible hose assembly according to claim 14, said pivot arm
being adjustable to provide said discharge angle in the range of
10.degree. to 90.degree. in a rearward direction toward said
proximal end of said hose assembly.
16. A flexible hose assembly according to claim 1, said flexible
hose being 400-2000 feet in length.
17. A flexible hose assembly according to claim 1, further
comprising a nozzle blaster joined to said flexible hose at said
distal end of said hose assembly, at least one of said thruster
ports being disposed in said flexible hose rearward of the point
where said flexible hose joins said nozzle blaster.
18. A method of horizontal well drilling comprising the following
steps: a) providing a flexible hose assembly comprising a flexible
hose having a proximal end and a distal end, said proximal end
being located rearward of said distal end, said flexible hose
having a plurality of thruster ports disposed therein with at least
one of said thruster ports being disposed rearward of said distal
end of said flexible hose, at least one of said thruster ports
adapted to direct a jet of pressurized fluid in a direction such
that a centerline drawn through said jet forms an acute discharge
angle with the longitudinal axis of said flexible hose rearward
from the location of said thruster port, at least one of said
thruster ports being an adjustable thruster port; b) lowering said
flexible hose assembly to a desired depth in a vertical well, and
redirecting said flexible hose assembly along a direction at an
angle to the longitudinal axis of said vertical well; c) forcing at
least 2,000 psi fluid through said flexible hose and said thruster
ports in said flexible hose; and d) drilling a horizontal bore into
the earth's strata adjacent said vertical well.
19. A method according to claim 18, said adjustable thruster port
having a variable opening area, said jet being discharged from said
thruster port through said opening.
20. A method according to claim 18, said adjustable thruster port
having a variable discharge angle.
21. A method according to claim 19, said adjustable thruster port
comprising a shutter for regulating the area of said opening of
said thruster port.
22. A method according to claim 21, said shutter being an iris.
23. A method according to claim 21, further comprising a servo
controller for actuating said shutter to thereby regulate said
opening area of said adjustable thruster port.
24. A method according to claim 23, said servo controller being
controlled via wireline or radio signal.
25. A method according to claim 20, said adjustable thruster port
comprising a servo-controlled pivot arm, said pivot arm being
adjustable to regulate said discharge angle.
26. A method according to claim 25, said pivot arm being adjustable
to provide said discharge angle in the range of 10.degree. to
90.degree. in a rearward direction toward said proximal end of said
hose assembly.
27. A method according to claim 18, further comprising the step of
drilling a horizontal bore from a vertical well at a depth of
50-2000 feet.
28. A method according to claim 18, further comprising the step of
withdrawing said hose assembly from said horizontal bore, and
during said withdrawing step forcing fluid through said thruster
ports to clean and ream said horizontal bore.
29. A method according to claim 18, said flexible hose assembly
further comprising a nozzle blaster attached to said flexible hose
at said distal end thereof, at least one of said thruster ports
being disposed in said flexible hose rearward of the point where
said flexible hose joins said nozzle blaster.
30. A flexible hose assembly according to claim 1, said fluid being
aqueous liquid.
31. A method according to claim 18, said fluid being aqueous
liquid.
32. A flexible hose assembly according to claim 1, further
comprising at least one position indicating sensor.
33. A flexible hose assembly according to claim 32, comprising a
plurality of said position indicating sensors provided along the
length of said flexible hose assembly.
34. A flexible hose assembly for horizontal well drilling
comprising a flexible hose, said flexible hose assembly having a
proximal end and a distal end, said proximal end being located
rearward of said distal end, said flexible hose having a plurality
of thruster ports disposed therein with at least one of said
thruster ports being disposed rearward of said distal end of said
flexible hose assembly, at least one of said thruster ports being
adapted to direct a jet of pressurized fluid in a direction such
that a centerline drawn through said jet forms an acute discharge
angle with the longitudinal axis of said flexible hose rearward
from the location of said thruster port, each of said thruster
ports having an opening with a cross-sectional area selected from
the group consisting of closed polygons, closed curvilinear shapes,
and shapes having at least one linear edge.
Description
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 09/825,329 filed Apr. 3, 2001, which claims
the benefit of U.S. Provisional Patent Application Serial No.
60/195,076 filed Apr. 6, 2000.
FIELD OF THE INVENTION
[0002] The invention relates to horizontal well drilling and more
particularly to a flexible hose assembly for horizontal well
drilling.
BACKGROUND OF THE INVENTION
[0003] In the process of drilling for hydrocarbons such as oil and
natural gas, vertical or substantially vertical wells have been
used most often in the past. Those wells will produce for a given
amount of time, then begin to dry up. At that point, it is
advantageous to drill out horizontally or laterally at an angle
from the vertical well in order to try and increase production of,
for example, crude oil.
[0004] There have been several attempts to find an economically
viable and reliable system for drilling into the untapped pay zones
adjacent an existing vertical well. Horizontal drilling has been
proposed as an alternative and has been described in U.S. Pat. Nos.
5,853,056, 5,413,184, 5,934,390, 5,553,680, 5,165,491, 5,458,209,
5,210,533, 5,194,859, 5,439,066, 5,148,877, 5,987,385, 5,899,958,
5,892,460, 5,528,566, 4,947,944, 4,646,831, 4,786,874, 5,410,303,
5,318,121, 4,007,797, 5,687,806, 4,640,362, 5,394,951, 1,904,819,
2,521,976 and Re. 35,386, the contents of all of which are
incorporated herein by reference.
[0005] U.S. Pat. No. 5,413,184 describes a method of horizontal
drilling that utilizes a flexible hose and a high pressure nozzle
blaster to bore into the earth's strata at significant depths, such
as 4000 feet. The nozzle blaster uses high pressure water to clear
a path through the strata. The nozzle blaster is advanced through
the strata by applying weight to the hose, i.e., slacking off the
tension in the vertical portion of the hose. Essentially, the
weight of the 4000 feet of hose above the nozzle blaster is used to
apply drilling force to the nozzle blaster, thus forcing it along
the horizontal path. While this method is effective at significant
depths due to the large amount of weight available, it is less
effective at shallower depths. At shallow depths, there simply is
not enough weight available to supply sufficient force to advance
the nozzle blaster through the strata.
[0006] In addition, drilling substantial lateral or horizontal
distances from the vertical well can be very difficult or time
consuming or otherwise inhibited due to the accumulation of the
loose cuttings from drilling in the lateral bore hole.
[0007] Thus, there is a need for an apparatus that will effectively
advance a drilling tool such as a nozzle blaster horizontally or
laterally at an angle relative to an existing vertical or
substantially vertical well, through the earth's strata for
horizontal or lateral drilling at shallow depths. Preferably, such
an improved apparatus will also effectively reduce or prevent the
accumulation of cuttings within a lateral bore.
SUMMARY OF THE INVENTION
[0008] A flexible hose assembly for horizontal well drilling is
provided. The assembly includes a flexible hose. The flexible hose
assembly has a proximal end and a distal end, wherein the proximal
end is located rearward of the distal end. The flexible hose has a
plurality of thruster ports disposed therein with at least one of
the thruster ports being disposed rearward of the distal end of the
flexible hose assembly. Each of the thruster ports is adapted to
direct a jet of pressurized fluid in a direction such that a
centerline drawn through the jet forms an acute discharge angle
with the longitudinal axis of the flexible hose rearward from the
location of the thruster port. At least one of the thruster ports
is an adjustable thruster port.
[0009] A method of horizontal well drilling is also provided which
includes the following steps: a) providing a flexible hose assembly
including a flexible hose that has a proximal end and a distal end,
wherein the proximal end is located rearward of the distal end, the
flexible hose having a plurality of thruster ports disposed therein
with at least one of the thruster ports being disposed rearward of
the distal end of the flexible hose, each of the thruster ports
being adapted to direct a jet of pressurized fluid in a direction
such that a centerline drawn through the jet forms an acute
discharge angle with the longitudinal axis of the flexible hose
rearward from the location of the thruster port, at least one of
the thruster ports being an adjustable thruster port; b) lowering
the flexible hose assembly to a desired depth in a vertical well,
and redirecting the flexible hose assembly along a direction at an
angle to the longitudinal axis of the vertical well; c) forcing at
least 2,000 psi fluid through the flexible hose and the thruster
ports in the flexible hose; and d) drilling a horizontal bore into
the earth's strata adjacent the vertical well.
[0010] A flexible hose assembly for horizontal well drilling is
also provided. The assembly includes a flexible hose. The flexible
hose assembly has a proximal end and a distal end, wherein the
proximal end is located rearward of the distal end. The flexible
hose has a plurality of thruster ports disposed therein with at
least one of the thruster ports being disposed rearward of the
distal end of the flexible hose assembly. Each of the thruster
ports is adapted to direct a jet of pressurized fluid in a
direction such that a centerline drawn through the jet forms an
acute discharge angle with the longitudinal axis of the flexible
hose rearward from the location of the thruster port. Each of the
thruster ports has an opening with a cross-sectional area selected
from the group consisting of closed polygons, closed curvilinear
shapes, and shapes having at least one linear edge.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a side view of a thruster coupling according to a
first preferred embodiment of the invention.
[0012] FIG. 2 is a cross-sectional view of the thruster coupling
taken along line 2-2 in FIG. 1.
[0013] FIG. 3 is a longitudinal cross-sectional view of the
thruster coupling taken along line 3-3 in FIG. 2.
[0014] FIG. 4 is a perspective view of a flexible hose having
thruster couplings according to the present invention.
[0015] FIG. 5A is a perspective view of a nozzle blaster for use
with the present invention.
[0016] FIG. 5B is an alternate perspective view of a nozzle blaster
for use with the present invention.
[0017] FIG. 6 is a perspective view of a flexible hose having
thruster ports provided directly in the sidewall according to an
embodiment of the invention.
[0018] FIG. 7 is a side view of a thruster coupling having
adjustable thruster ports according to a second preferred
embodiment of the invention.
[0019] FIG. 8 is a cross-sectional view of the thruster coupling
taken along line 8-8 in FIG. 7.
[0020] FIG. 9 is a close-up view of an adjustable thruster port
indicated at broken circle 9 in FIG. 7.
[0021] FIG. 10 is an alternative preferred embodiment of a thruster
coupling having adjustable thruster ports.
[0022] FIG. 11 is a further alternative preferred embodiment of a
thruster coupling having adjustable thruster ports.
[0023] FIG. 12 is a perspective view of a flexible hose having
thruster couplings according to the embodiment illustrated in FIG.
11.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE
INVENTION
[0024] In the description that follows, when a preferred range such
as 5 to 25 (or 5-25) is given, this means preferably at least 5,
and separately and independently, preferably not more than 25. As
used herein, the following terms having the following meanings:
"gal/min" means gallons per minute and "psi" means pounds per
square inch.
[0025] As used herein, the term vertical well refers to a well bore
in the earth having an opening at the earth's surface. A vertical
well can be substantially vertical relative to the earth's surface,
or it can be drilled at an angle, e.g. an acute angle, relative to
the earth's surface instead of straight down. Also as used herein,
when a horizontal well bore or a horizontal well or direction is
mentioned, the word "horizontal" indicates a well bore or direction
that is at an angle relative to the vertical well from which the
horizontal bore is drilled or depends. For example, as used herein
when a horizontal bore is drilled from a vertical well bore, it is
not necessary or required that either the vertical well bore be
truly vertical, or that the horizontal bore drilled therefrom be
truly horizontal. All that is required is that the vertical well
bore have an opening at the earth's surface and that the horizontal
bore be drilled out from the vertical well at an angle relative to
the vertical well. Commonly, the vertical well is truly or
substantially vertical, and the horizontal bore drilled therefrom
is truly or substantially horizontal; however this is not required
or necessary in the present invention.
[0026] The invention can be used with respect to oil wells, natural
gas wells, water wells, solution mining wells, and other wells. The
invention includes a flexible hose assembly comprising a flexible
hose with thrusters and a nozzle blaster for horizontal well
drilling. The hose assembly is fed down into the bore of an
existing vertical well to a specified depth, at which point it is
redirected along a horizontal direction that can be substantially
perpendicular to the vertical well. Preferably, the hose assembly
is fed into the well by a coil tubing injector as known in the art.
Redirection of the hose assembly is preferably accomplished via an
elbow or shoe in upset tubing as is known in the art, less
preferably via some other known means.
[0027] The hose assembly includes a flexible hose having a proximal
end and a distal end, such that proximal end is located rearward of
the distal end. Preferably, the flexible hose is supplied with a
plurality of thruster couplings disposed along the length of the
hose. Each coupling contains one or more thrusters or thruster
ports, each thruster port comprising a hole or opening through the
coupling wall to allow the passage of water or other pressurized
fluid or liquid therethrough. In one preferred embodiment, the
thruster ports are oriented in a substantially rearward direction
about the circumference of the thruster coupling such that high
pressure water or other fluid exits the holes at a substantially
rearward angle and enters the horizontal bore in a direction
effective to impinge upon the walls of the bore, thus thrusting the
hose (and thereby the nozzle blaster) forward through the bore.
[0028] In a further preferred embodiment, the thruster ports are
adjustable, meaning that they have variable opening area or
diameter, variable discharge angle or both. In this embodiment, the
opening diameter or the angle of discharge of the adjustable
thrusters can be varied to deliver a variable degree of thrust to
the hose assembly (and nozzle blaster) depending on how much force
is required or desired to effectively drill through the strata
ahead of the nozzle blaster (e.g. sandstone requires comparatively
less thrust or drilling force relative to granite or igneous rock).
In addition, varying the angle of discharge can aid in steering the
flexible hose assembly as it drills a horizontal bore, and in
clearing the horizontal bore of drill cuttings and other
debris.
[0029] With reference to FIG. 4, there is shown generally a
flexible hose assembly 10 according to the invention, which
preferably comprises a nozzle blaster 24 and a flexible hose 11.
Flexible hose 11 has and comprises a plurality of flexible hose
sections 22, a pair of pressure fittings 23 attached to the ends of
each hose section 22, and a plurality of thruster couplings 12,
each of which joins a pair of adjacent pressure fittings 23. Hose
assembly 10 comprises a nozzle blaster 24 at its distal end and is
connected to a source (not shown) of high pressure fluid,
preferably an aqueous liquid, preferably water, less preferably
some other liquid, at its proximal end. Couplings 12 are spaced at
least, or not more than, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90 or
100 feet apart from each other in hose 11. The total hose length is
preferably at least or not more than 100 or 200 or 400 or 600 or
700 or 800 or 900 or 1000 or 1200 or 1400 or 1600 or 1800 or 2000
feet. Hose sections 22 are preferably flexible hydraulic hose known
in the art, comprising a steel braided rubber-Teflon
(polytetrafluoroethylene) mesh, preferably rated to withstand at
least 5,000, preferably at least 10,000, preferably at least
15,000, psi water pressure. High pressure water is preferably
supplied at at least 2,000, 5,000, 10,000, 15,000, or 18,000 psi,
or at 5,000 to 10,000 to 15,000 psi. When used to drill
horizontally from a vertical well, the hose extends about or at
least or not more than 7, 10, 50, 100, 200, 250, 300, 350, 400,
500, 1000, or 2000 feet horizontally from the original vertical
well. In one embodiment the hose extends about 440 feet
horizontally from the original vertical well.
[0030] As illustrated in FIG. 1, in a first preferred embodiment
thruster coupling 12 comprises a coupling or fitting, preferably
made from metal, preferably steel, most preferably stainless steel,
less preferably aluminum. Less preferably, coupling 12 is a fitting
made from plastic, thermoset, or polymeric material, able to
withstand 5,000 to 10,000 to 15,000 psi of water pressure. Still
less preferably, coupling 12 is a fitting made from ceramic
material. It is important to note that when a drilling fluid other
than water is used, the material of construction of the couplings
12 must be selected for compatibility with the drilling fluid and
yet still withstand the desired fluid pressure. Coupling 12 has two
threaded end sections 16 and a middle section 14. Preferably, end
sections 16 and middle section 14 are formed integrally as a single
solid part or fitting. Threaded sections 16 are female-threaded to
receive male-threaded pressure fittings 23 which are attached to,
preferably crimped within the ends of, hose sections 22 (FIG. 4).
Alternatively, the fittings 23 can be attached to the ends of the
hose sections 22 via any conventional or suitable means capable of
withstanding the fluid pressure. In the illustrated embodiment,
each fitting 23 has a threaded portion and a crimping portion which
can be a unitary or integral piece, or a plurality of pieces joined
together as known in the art. Alternatively, the threaded
connections may be reversed; i.e. with male-threaded end sections
16 adapted to mate with female-threaded pressure fittings attached
to hose sections 22. Less preferably, end sections 16 are adapted
to mate with pressure fittings attached to the end of hose sections
22 by any known connecting means capable of providing a
substantially water-tight connection at high pressure, e.g.
5,000-15,000 psi. Middle section 14 contains a plurality of holes
or thruster ports 18 which pass through the thickness of wall 15 of
coupling 12 to permit water to jet out. Though the thruster ports
18 are shown having an opening with a circular cross-section, the
thruster port openings can be provided having any desired cross
section; e.g. polygonal, curvilinear or any other shape having at
least one linear edge, such as a semi-circle. Coupling 12
preferably is short enough to allow hose 11 to traverse any bends
or elbows in the upset tubing and any shoes or adapters used
therewith. Therefore, coupling 12 is formed as short as possible,
preferably having a length of less than about 3, 2, or 1.5 inches,
more preferably about 1 inch or less than 1 inch. Hose 11 (and
therefore couplings 12 and hose sections 22) preferably has an
outer diameter of about 0.25 to about 1.25 inches, more preferably
about 0.375 to about 0.5 inches, and an inner diameter preferably
of about 0.125 inches. Couplings 12 have a wall thickness of
preferably about 0.025-0.25, more preferably about 0.04-0.1,
inches.
[0031] Optionally, hose 11 is provided with couplings 12 formed
integrally therewith, or with thruster ports 18 disposed directly
in the sidewall of a contiguous, unitary, non-sectioned hose at
spaced intervals along its length (see FIG. 6). A hose so comprised
obviates the need of threaded connections or other connecting means
as described above.
[0032] In the embodiments shown in FIGS. 1 and 7, thruster ports 18
have hole axes 20 which form a discharge angle .beta. with the
longitudinal axis of the coupling 12. The discharge angle .beta. is
preferably 5.degree. to 95.degree., more preferably 10.degree. to
90.degree., more preferably 10.degree. to 80.degree., more
preferably 15.degree. to 70.degree., more preferably 20.degree. to
60.degree., more preferably 25.degree. to 55.degree., more
preferably 30.degree. to 50.degree., more preferably 40.degree. to
50.degree., more preferably 40.degree. to 45.degree., more
preferably about 45.degree.. The thruster ports 18 are also
oriented such that a water jet passing through them exits the
coupling 12 in a substantially rearward direction; i.e. in a
direction such that a centerline drawn through the exiting water
jet forms an acute angle (discharge angle .beta.) with the
longitudinal axis of the flexible hose rearward from the location
of the thruster port, toward the proximal end of the hose assembly.
In this manner, high-pressure water jets 30 emerging from thruster
ports 18 impart drilling force or thrust to the nozzle blaster,
thus forcing the nozzle blaster forward into the earth strata (see
FIG. 4). As illustrated in FIG. 2, a plurality of thruster ports 18
are disposed in wall 15 around the circumference of coupling 12.
There are 2 to 6 or 8 ports, more preferably 3 to 5 ports, more
preferably 3 to 4 ports. Thruster ports 18 are spaced uniformly
about the circumference of coupling 12, thus forming an angle
.alpha. between them. Angle .alpha. will depend on the number of
thruster ports 18, and thus preferably will be from 45.degree. or
60.degree. to 180.degree., more preferably 72.degree. to
120.degree., more preferably 90.degree. to 120.degree.. Thruster
ports 18 are preferably about 0.010 to 0.017 inches, more
preferably 0.012 to 0.016 inches, more preferably 0.014 to 0.015
inches in diameter.
[0033] As best seen in FIGS. 1 and 2, thruster ports 18 are formed
in the wall 15 of coupling 12, extending in a substantially
rearward direction toward the proximal end of the hose assembly 10,
connecting inner opening 17 at the inner surface of wall 15 with
outer opening 19 at the outer surface of wall 15. The number of
couplings 12, as well as the number and size of thruster ports 18
depends on the desired water pressure and water flow rate. If a
water source of only moderate delivery pressure is available, e.g.
5,000-7,000 psi, then relatively fewer couplings 12 and thruster
ports 18, as well as possibly smaller diameter thruster ports 18
should be used. However, if higher pressure water is supplied, e.g.
10,000-15,000 psi, then more couplings 12 and thruster ports 18 can
be utilized. The number of couplings 12 and thruster ports 18, the
diameter of thruster ports 18, and the initial water pressure and
flow rate are all adjusted to achieve water flow rates through
nozzle blaster 24 of 1-10, more preferably 1.5-8, more preferably
2-6, more preferably 2.2-3.5, more preferably 2.5-3, gal/min.
[0034] In the first preferred embodiment illustrated in FIG. 1, the
thruster ports 18 are provided as unobstructed openings or holes
through the side wall of the thruster coupling 12. The ports 18 are
provided or drilled at an angle so that the exiting pressurized
fluid jets in a rearward direction as explained above.
[0035] In the second preferred embodiment illustrated in FIG. 7,
the thruster couplings 12 and thruster ports 18 are similarly
provided as described above shown in FIG. 1, except that the
thruster port or ports 18 include a shutter 31. The shutter 31 is
preferably an iris as shown in FIG. 7, and shown close-up in FIG.
9. The shutter 31 is actuated by a servo controller 32 (pictured
schematically in the figures) which is controlled by an operator at
the surface via wireline, radio signal or any other suitable or
conventional means. The servo controller 32 is preferably provided
in the sidewall of the coupling 12 as shown in FIG. 8, or is
mounted on the inner wall surface of the coupling 12. The servo
controller 32 has a small motor to control or actuate the shutter
31 to thereby regulate the diameter or area of the opening 34 for
the thruster port 18. A fully open shutter 31 results in the
maximum possible thrust from the associated thruster port 18
because the maximum area is available for the expulsion of high
pressure fluid. An operator can narrow the opening 34 by closing
the shutter 31 to regulate the amount of thrust imparted to the
hose assembly by the associated thruster port 18. The smaller
diameter the opening 34, the less thrust provided by the thruster
port 18. Although an iris is shown, it will be understood that
other mechanisms can be provided for the shutter 31 which are
conventional or which would be recognized by a person of ordinary
skill in the art; e.g. sliding shutter, flap, etc. The servo
controller 32 is preferably a conventional servo controller having
a servo motor that is controlled in a conventional manner. Servo
controllers are generally known or conventional in the art.
[0036] In addition to providing thrust to the hose (and nozzle
blaster 24), thruster ports 18 equipped with shutters 31 can be
used to guide or steer the hose assembly 10 as it drills a
horizontal bore. It will be understood by a person of ordinary
skill in the art that during use, the hose assembly 10 is very
rigid, i.e. it is biased in a straight or linear configuration due
to the internal fluid pressure (e.g. 5,000 or 10,000 or 15,000
psi). This is because the internal fluid pressure seeks to expand
the hose assembly 10 from within, thereby forcing the assembly to
remain stiff and straight without bending. By regulating the
relative thrust provided by different thruster ports 18 at spaced
circumferential locations about the hose assembly at a particular
axial position along its length, the assembly 10 can be steered at
that axial location.
[0037] For example, referring to FIG. 8, if thruster port 18a
provides greater thrust than either of ports 18b or 18c, then the
hose assembly 10 will be driven in a lateral direction (relative to
the hose's longitudinal axis) substantially opposite the position
of the thruster port 18a as a result of the excess thrust (i.e.
direction indicated by arrow B in FIG. 8). The lateral thrust is
countered by and must be balanced against the assembly's 10
straight and rigid bias (described above) to provide the desired
lateral positioning or steering effect. The assembly's straight and
rigid bias makes control of the assembly 10 via the thrusters
easier to achieve because the assembly is constantly trying to
right or straighten itself. Therefore, the thrusters' port openings
34 can be finely regulated to control the amount of thrust acting
against the straightening bias to provide very precise lateral
positioning and steering capability for the hose assembly 10.
[0038] Likewise, a corresponding lateral thrust can be imparted by
either of thruster ports 18b and/or 18c in the appropriate
direction. It will be understood that the relative thrust of all
the thrusters located at the same axial position along the length
of the hose assembly 10 (i.e. all the thrusters in a single
thruster coupling 12) can be simultaneously regulated in concert to
guide the lateral position of the hose assembly 10 at that
location. By similarly coordinating the relative thrust of all the
groups of thruster ports 18 disposed at discrete axial positions
along the length of the hose assembly 10, an operator can guide or
steer the assembly 10 as it drills horizontally from the vertical
well to thereby provide a specific desired configuration for the
hose assembly 10 along its entire length as it drills. This way, a
horizontal bore having a desired nonlinear shape or overall
configuration can be drilled; the horizontal bore need not be
straight. Alternatively, if a straight or linear horizontal bore is
desired, the hose assembly 10 (particularly at or near its distal
end where the nozzle blaster 24 is located) can be steered to
ensure a straight path despite the presence of obstructions or
other forces that could divert the blaster's 24 path.
[0039] It will be understood that when complex shape or drilling
pathway configurations are desired, it would be very difficult for
a human operator to properly control and regulate the relative
thrust for all of the thruster ports 18 along the hose assembly's
length. Therefore, it is desirable and preferred to have the
adjustable thruster ports 18 controlled by a computer 40 that has
been programmed with the desired drilling configuration. Means and
methods for programming a computer to control a plurality of servo
controllers (for regulating shutters 31) are conventional, and are
well understood by persons of ordinary skill in the art.
[0040] Preferably, the flexible hose 11 is provided with a
plurality of position indicating sensors 35 along its length.
Position indicating sensors 35 are shown schematically in FIG. 4
attached to the thruster couplings 12 and nozzle blaster 24.
Alternatively, the position indicating sensors 35 can be provided
in the coupling walls, or in the hose wall along its length. The
position indicating sensors 35 can emit a radio signal or can be
monitored by wireline from the surface to determine the location
and configuration of the flexible hose. The adjustable thruster
ports 18 can be controlled as described above based on position and
configuration information received from these position indicating
sensors 35. Preferably, the computer receives information from the
position indicating sensors 35 and regulates the adjustable
thrusters based on that information to achieve the desired steering
and position control of the hose assembly 10 as it drills a
horizontal bore.
[0041] FIG. 10 shows an alternative preferred embodiment of the
adjustable thruster ports 18. In this embodiment, the adjustable
thruster ports 18 comprise flap shutters 31a adjacent to, and
adapted to seal off, the outer openings 19 of the ports 18. In this
embodiment, the flap shutters 31a are servo controlled similarly as
described above, and can be opened or closed to variable degrees as
desired to provide a desired amount of thrust. One advantage of
this embodiment is that in addition to regulating the flowrate of
the jets 30, the flap shutters 31a also can be used to regulate the
discharge angle .beta.. This embodiment is less preferred because
the flap shutters 31a are liable to catch on the horizontal bore
wall or on some obstruction therein. Further, the flap shutters can
inhibit the passage of rearwardly traveling cuttings to exit the
horizontal bore as described below.
[0042] FIG. 11 shows yet another alternative preferred embodiment
of the invention, where the thruster ports 18 are provided in
servo-controlled pivot arms 38. In this embodiment, the discharge
angle .beta. between the centerline drawn through the exiting water
jet 30 and the longitudinal axis of the flexible hose can be
regulated. The smaller angle .beta., the larger axial thrust force
vector for a given fluid pressure and discharge rate; conversely,
the larger angle .beta., the smaller axial thrust force vector for
the same fluid pressure and discharge rate. Thus, the degree of
forward thrust for the hose assembly 10 can be controlled for a
given fluid pressure and discharge rate by regulating the discharge
angle of the water jets 30. This is achieved by controlling the
pivot arms 38 to provide the desired discharge angle .beta..
Preferably, the pivot arms 38 are adjustable to provide a discharge
angle in the range of 10.degree. to 90.degree., 10.degree. to
80.degree., 15.degree. to 70.degree., 20.degree. to 60.degree.,
25.degree. to 50.degree., 30.degree. to 50.degree., or 40.degree.
to 50.degree. in a rearward direction toward the proximal end of
the hose assembly 10.
[0043] In addition to providing thrust, the thruster ports 18 also
provide another important function. Thruster ports 18 keep the bore
clear behind nozzle blaster 24 as the rearwardly jetting high
pressure fluid (water) washes the drill cuttings out of the
horizontal bore so that the cuttings do not accumulate in the
horizontal bore. The high pressure water or aqueous liquid forced
through the thruster ports 18 also cleans and reams the bore by
clearing away any sand and dirt that has gathered behind the
advancing nozzle blaster 24, as well as smoothing the wall of the
freshly drilled bore.
[0044] This is an important feature because, left to accumulate,
the cuttings and other debris can present a significant obstacle to
horizontal drilling, effectively sealing of already-drilled
portions of the horizontal bore around the advancing hose assembly
10. This can make removal of the hose assembly 10 difficult once
drilling is completed. In a worst case, the remaining debris can
cause the horizontal bore to reseal once the hose assembly 10 has
been withdrawn. By forcing these cuttings rearward to exit the
lateral bore, the rearwardly directed water jets 30 ensure the
horizontal bore remains substantially open and clear after drilling
is completed and the hose assembly 10 is removed. By providing the
thruster ports 18 along substantially the entire length of the hose
assembly 10, drill cuttings can be driven out of the horizontal
bore from great distances into the horizontal bore, preferably at
least 50, 100, 200, 250, 300, 350, 400, 500, 1000, or more,
feet.
[0045] Nozzle blaster 24 is of any type known in the art, for
example, the type shown in FIGS. 5A-5B. Nozzle blaster 24 comprises
a plurality of holes 50 disposed about a front portion 46a which
preferably has a substantially domed shape. Holes 50 are positioned
to form angle .theta. with the longitudinal axis of nozzle blaster
24. Angle .theta. is 10.degree.-30.degree., more preferably
15.degree.-25.degree., more preferably about 20.degree.. Nozzle
blaster 24 also comprises a plurality of holes 46b, which are
oriented in a reverse or rearward direction on a rear portion 60 of
nozzle blaster 24, the direction and diameter of holes 46b being
similar to that of thruster ports 18 disposed around couplings 12.
Holes 46b serve a similar function as thruster ports 18 to impart
forward drilling force to nozzle blaster 24 and to wash drill
cuttings rearward to exit the horizontal bore. Optionally, front
portion 46a is rotatably coupled to rear portion 60, with holes 50
oriented at an angle such that exiting high-pressure water imparts
rotational momentum to front portion 46a, thus causing front
portion 46a to rotate while drilling. Rear portion 60 is either
fixed with respect to hose 11 unable to rotate, or is rotatably
coupled to hose 11 thus allowing rear portion 60 to rotate
independently of hose 11 and front portion 46a. In this embodiment,
holes 46b are oriented at an angle effective to impart rotational
momentum to rear portion 60 upon exit of high-pressure water, thus
causing rear portion 60 to rotate while drilling. Holes 50 and 46b
can be oriented such that front and rear portions (46a and 60
respectively) rotate in the same or opposite directions during
drilling.
[0046] Thruster ports 18 and 46b are oriented in a reverse or
rearward direction, relative to forward direction A (FIGS. 1 and
4), toward the proximal end of the hose assembly to thrust the
nozzle blaster forward to drill the bore. High pressure water is
propelled through thruster ports 18 forming high pressure water
jets 30 which impinge on the walls of the bore at such an angle as
to impart drilling force to the nozzle blaster 24. Thus, the
present invention has great utility at shallow depths where the
length (and thereby the weight) of flexible hose in the vertical
well is generally insufficient to supply adequate drilling force to
the nozzle blaster 24 to propel it forward while drilling. As such,
the present invention is effectively used to drill horizontal bores
at depths of at least, or not more than, 50, 100, 200, 300, 400,
500, 600, 700, 800, 900, 1000, or 2000 feet. However, the invented
hose assembly can also be advantageously used to drill horizontal
bores at greater depths, e.g. 5,000, 8,000, 10,000, or 15,000 feet
or greater.
[0047] Although the hereinabove described embodiments of the
invention constitute the preferred embodiments, it should be
understood that modifications can be made thereto without departing
from the scope of the invention as set forth in the appended
claims.
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