U.S. patent application number 10/978589 was filed with the patent office on 2005-03-24 for apparatus and method for installing casing in a borehole.
This patent application is currently assigned to Halliburton Energy Services, Inc.. Invention is credited to Grigsby, Tommy, Phillips, Ian, Vidrine, William L..
Application Number | 20050061518 10/978589 |
Document ID | / |
Family ID | 32030142 |
Filed Date | 2005-03-24 |
United States Patent
Application |
20050061518 |
Kind Code |
A1 |
Vidrine, William L. ; et
al. |
March 24, 2005 |
Apparatus and method for installing casing in a borehole
Abstract
An apparatus and method of installing a casing string in a
borehole, the apparatus comprising a propulsion system movable
through the borehole; the propulsion system having an attachment
member; and the attachment member being engagable with the casing
string causing the casing string to move with the propulsion system
through the borehole. The apparatus further including a conduit for
circulating fluids through the propulsion system to provide the
power to move the propulsion system. The propulsion system may also
be disposable.
Inventors: |
Vidrine, William L.;
(Spring, TX) ; Grigsby, Tommy; (New Orleans,
LA) ; Phillips, Ian; (Aberdeen, GB) |
Correspondence
Address: |
CONLEY ROSE, P.C.
P. O. BOX 3267
HOUSTON
TX
77253-3267
US
|
Assignee: |
Halliburton Energy Services,
Inc.
Houston
TX
|
Family ID: |
32030142 |
Appl. No.: |
10/978589 |
Filed: |
November 1, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10978589 |
Nov 1, 2004 |
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10262126 |
Oct 1, 2002 |
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6654216 |
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Current U.S.
Class: |
166/380 ;
166/77.1 |
Current CPC
Class: |
E21B 23/08 20130101;
E21B 43/10 20130101; E21B 23/04 20130101; E21B 23/001 20200501 |
Class at
Publication: |
166/380 ;
166/077.1 |
International
Class: |
E21B 019/16 |
Claims
What is claimed is:
1. An apparatus for installing casing in a borehole, the apparatus
comprising: a propulsion system movable through the borehole and at
least a portion of the casing; the propulsion system comprising an
attachment member; and the attachment member being engageable with
the casing and causing the casing to move with the propulsion
system through the borehole.
2. The apparatus of claim 1 wherein the attachment member includes
an extension projecting from the propulsion system.
3. The apparatus of claim 2 wherein the propulsion system extension
projects radially outward from the uphole end of the propulsion
system.
4. The apparatus of claim 3 wherein the extension engages the
casing causing the casing to move with the propulsion system.
5. The apparatus of claim 1 further including a conduit for
circulating fluids through the propulsion system to provide the
power to move the propulsion system.
6. The apparatus of claim 5 wherein the conduit is coiled tubing
extending into the borehole comprising one end connected to the
propulsion system.
7. The apparatus of claim 1 wherein the propulsion system is
disposable.
8. An assembly for installing a casing string in a borehole, the
apparatus comprising: a propulsion system movable through the
borehole and a portion of the casing string; the propulsion system
comprising an attachment member; a casing section connected to the
casing string and comprising a connection member; and the
attachment member being engageable with the connection member and
causing the casing string to move with the propulsion system
through the borehole.
9. The assembly of claim 8 wherein the propulsion system is
disposable.
10. The assembly of claim 8 wherein the connection member projects
radially inward from the casing section and the attachment member
projects radially outward of the propulsion system.
11. The assembly of claim 10 wherein the connection member is an
annular collar and the attachment member is an annular shoulder,
the annular collar comprising an inner diameter large enough to
allow the propulsion system to pass through but small enough to
prevent the annular shoulder from passing through.
12. An assembly for installing casing in a borehole, the assembly
comprising: a propulsion system movable through the borehole; the
propulsion system comprising an attachment member; a casing string
connected to the propulsion system; and the casing string
comprising a flowbore for circulating fluids through the propulsion
system to provide the power to move the propulsion system.
13. The assembly of claim 12 wherein the casing string is sealed to
the propulsion system.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation application of
U.S. application Ser. No. 10/262,136, filed Oct. 1, 2002 and
entitled Apparatus and Methods for Installing Casing in a Borehole,
this application being hereby incorporated herein by reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable.
BACKGROUND OF THE INVENTION
[0003] The embodiments relate generally to methods and apparatus
for movement of equipment in passages. More particularly, the
embodiments relate to a propulsion system for pulling casing into
boreholes.
[0004] The art of drilling vertical, inclined, and horizontal
boreholes plays an important role in the oil and gas industry. For
example, a typical oil or gas well comprises a vertical borehole
that is drilled by a rotary drill bit attached to the end of a
drill string. The drill string is typically constructed of a series
of connected links of drill pipe that extend between surface
equipment and the drill bit. A drilling fluid, such as drilling
mud, is pumped from the surface through the interior surface or
flow channel of the drill string to the drill bit. The drilling
fluid is used to cool and lubricate the drill bit, and remove
debris and rock chips from the borehole created by the drilling
process. The drilling fluid returns to the surface, carrying the
cuttings and debris, through the space between the outer surface of
the drill pipe and the inner surface of the borehole.
[0005] Conventional drilling often requires drilling numerous
boreholes to recover hydrocarbons, such as gas and oil, or mineral
deposits. For example, drilling for oil and gas usually includes
drilling a vertical borehole until the reservoir is reached. The
hydrocarbons are then pumped from the reservoir to the surface. As
known in the industry, often a large number of vertical boreholes
must be drilled within a small area to recover the hydrocarbons
within the reservoir. This requires a large investment of resources
and equipment and is very expensive. Additionally, the hydrocarbons
within the reservoir may be difficult to recover for several
reasons. For instance, the size and shape of the formation, the
depth at which the hydrocarbons are located, and the location of
the reservoir may make exploitation of the reservoir very
difficult. Further, drilling for oil and gas located under bodies
of water, such as the North Sea, often presents greater
difficulties.
[0006] In order to recover hydrocarbons from these difficult to
exploit reservoirs, it may be desirable to drill a borehole that is
not vertically orientated. For example, the borehole may be
initially drilled vertically downwardly to a predetermined depth
and then drilled at an inclination to vertical to the desired
target location. In other situations, it may be desirable to drill
an inclined or horizontal borehole beginning at a selected depth.
This allows the hydrocarbons located in difficult-to-reach
locations to be recovered.
[0007] While several methods of drilling are known in the art, two
frequently used methods to drill vertical, inclined, and horizontal
boreholes are generally known as rotary drilling and coiled tubing
drilling. In rotary drilling, a drill string, consisting of a
series of connected segments of drill pipe, is lowered from the
surface using surface equipment such as a derrick and draw works.
Attached to the lower end of the drill string is a bottom hole
assembly ("BHA"). The BHA typically includes a drill bit and may
include other equipment known in the art such as drill collars,
stabilizers, and heavy-weight pipe. The other end of the drill
string is connected to a rotary table or top drive system located
at the surface. The top drive system rotates the drill string, the
BHA, and the drill bit, allowing the rotating drill bit to
penetrate into the formation. The direction of the rotary drilled
borehole can be gradually altered by using known equipment such as
a downhole motor with an adjustable bent housing to create inclined
and horizontal boreholes.
[0008] Another type of known drilling is coiled tubing drilling. In
coiled tubing drilling, the drill string tubing is fed into the
borehole by an injector assembly. In contrast to rotary drilling,
the drill string is not rotated. Instead, a downhole motor as part
of the BHA provides rotation to the drill bit. Because the coiled
tubing is not rotated or used to force the drill bit into the
formation, the strength and stiffness of the coiled tubing is
typically much less than that of the drill pipe used in comparable
rotary drilling. Thus, the thickness of the coiled tubing is
generally less than the drill pipe thickness used in rotary
drilling, and the coiled tubing generally cannot withstand the same
rotational and tension forces in comparison to the drill pipe used
in rotary drilling.
[0009] The use of coiled tubing drilling typically eliminates the
use of conventional rigs and conventional drilling equipment. See,
for example, U.S. Pat. Nos. 5,215,151; 5,394,951 and 5,713,422, all
hereby incorporated herein by reference. The BHA may also include a
propulsion system that propels the bit down the borehole. One such
propulsion system is a thruster that pushes off the lower terminal
end of the coiled tubing and does not rely upon contacting or
gripping the inside wall of the borehole.
[0010] Another such self-propelled propulsion system is
manufactured by Western Well Tool. The propulsion system includes
an upper and lower housing with a packerfoot mounted on each end.
Each housing has a hydraulic cylinder and ram for moving the
propulsion system within the borehole. The propulsion system
operates by the lower packerfoot expanding into engagement with the
wall of the borehole with the ram in the lower housing extending in
the cylinder to force the bit downhole. Simultaneously, the upper
packerfoot contracts and moves to the other end of the upper
housing. Once the ram in the lower housing completes its stroke,
then the hydraulic ram in the upper housing is actuated to propel
the bit and motor further downhole as the lower packerfoot
contracts and resets at the other end of the lower housing. This
cycle is repeated to continuously move the BHA within the borehole.
The propulsion system can propel the BHA in either direction in the
borehole. Flow passages are provided between the packerfeet and
housings to allow the passage of drilling fluids through the
annulus formed by the coiled tubing and borehole.
[0011] Various companies manufacture other types of self-propelled
propulsion systems for propelling the bit and pulling steel coiled
tubing in the well. These propulsion systems include self-propelled
wheels that frictionally engage the wall of the borehole. However,
there is very little clearance between the wheels of the propulsion
system and the wall of the borehole and problems arise when the
wheels encounter ridges or other variances in the dimensions of the
wall of the borehole. Further, at times there is an inadequate
frictional engagement between the wheels and the wall of the
borehole to adequately propel the propulsion system.
[0012] Other companies also offer propulsion systems to "walk" the
end of a wireline down a cased borehole. However, these propulsion
systems engage the interior wall of a casing having a known inside
dimension. One such propulsion system is manufactured by
Schlumberger.
[0013] Another form of drilling is composite tubing drilling.
Similar to coiled tubing drilling, a propulsion system can also be
used with composite tubing to drill a borehole. An example of a
drilling system using a propulsion system with composite coiled
tubing is U.S. Pat. No. 6,296,066, hereby incorporated herein by
reference. With composite tubing drilling, instead of using coiled
metal tubing, composite coiled tubing is used as the drilling
conduit for transfer of the drilling fluids. With composite tubing,
the drill string is also not rotated.
[0014] For all of the methods of drilling discussed above, during
the course of the drilling program, the borehole typically has one
or more "casing strings" run and cemented in place. A typical
drilling program first involves drilling a large diameter borehole
from the earth's surface for several thousand feet. A "surface
casing" string is then run into the borehole and cemented in place.
After the cement in the annulus has cured or hardened, another
drill bit is utilized to drill through the cement in the surface
casing to drill a second and deeper borehole into the earth
formations. Typically, the subsequent drill bit has a smaller
diameter that the initial drill bit such that the second borehole
has a smaller diameter than the diameter of the surface borehole.
However, it should be appreciated that bi-center bits and wing
reamers may be used to enlarge the diameter of the second
borehole.
[0015] With respect to the section of borehole subsequently drilled
below a surface casing; at an appropriate depth, the drilling of
the borehole is discontinued and a string of pipe commonly called a
casing or liner is inserted through the surface casing. As a matter
of nomenclature, a liner is a string of pipe typically suspended in
the lower end of the previously set casing by a liner hanger so
that the lower end of the liner does not touch the bottom of the
borehole and the liner thus is suspended under the tension of the
pipe weight on the liner hanger. In some instances, a liner is set
on the bottom of the borehole but its upper end does not extend to
the earth's surface.
[0016] If the pipe set in the borehole subsequently drilled extends
to the surface of the earth it is also called a casing. When the
cementing operation is completed and the cement sets, there is a
column of cement in the annulus of the subsequent string of pipe.
The casing strings are usually comprised of a number of joints,
each being on the order of forty feet long, connected to one
another by threaded connections or other connection means. Also,
the joints are typical metal pipes, but may also be non-meal
materials such as composite tubing.
[0017] Typically, the casing string is merely gravity fed into a
vertical borehole. If a top drive rig is used, the rig can
hydraulically force the casing string down into the borehole. If
gravity fed, however, the weight of the casing is used to install
the casing in the borehole. Typically, a casing shoe is disposed on
the lower end of the casing string to close off the lower end of
the casing string. The casing shoe closes off the lower end of the
string so that the casing then serves as a pressure vessel in which
fluid pressure can be applied to help force the casing down hole.
The shoe typically is bullet shaped with a spherical-type face. A
float valve may be attached to the lower end of the casing that
allows the fluid to pass down the casing and out through the lower
end to allow fluid circulation.
[0018] The advent in recent years of highly deviated or horizontal
wells in the oil and gas industry has increased both the frequency
and seriousness of difficulties encountered while running borehole
casing strings. Particularly, problems occur in a borehole that has
an extended reach horizontal portion. Horizontal wells may be at
shallow depths where the vertical portion of the well is small.
With a small vertical portion, the vertical length of the casing is
short whereby minimum weight is provided by the drill string to
allow gravity to assist in setting the casing. In addition, in a
horizontal well, the drag becomes so great on the casing string
that it can no longer be forced into the borehole. Also, if a
borehole has high build rates, such as 30.degree. per hundred feet
plus, there can be a wash out in the curved section. If there is a
wash out, the end of the pipe may tend to bury itself into the wash
out portion rather than follow the bends or curves in the borehole.
Thus, the end of the pipe could dead end into one of the cavities
caused by the wash out rather than make the turn in the
borehole.
[0019] Another prior art solution to these problems includes
floating the pipe by making the string of casing a closed vessel
and either filling the casing with a low density fluid or possibly
only having air in the casing. The borehole is filled with fluid to
place a column on the well to maintain control. The fluid inside
the casing has a lower density than the fluid forming the column in
the annulus and causes the casing string to tend to be buoyant and
"float" in the borehole fluid. Causing the casing string to float
reduces the drag on the highly deviated borehole wall. This
methodology, however, is delicate because of the collapse pressure
of the casing. The casing will collapse if the pressure
differential across the casing wall becomes too great. In any
event, floating the casing still does not completely eliminate the
drag on the casing and thus the methodology is still subject to the
problems discussed above for non-floating casing.
[0020] The consequence of encountering such difficulties are, at
best, delays in the schedule of the well program and, at worst,
having to drill all or part of the well again. In any case,
significant additional cost is involved. Thus, there exists a need
for an apparatus and method of installing casing into
highly-deviated and horizontal boreholes. The casing must thus be
able to maneuver through curves in the borehole. The casing must
also be able to be installed in boreholes of great length, in the
order of 50,000 feet. The apparatus and method of installing the
casing must also cost-effectively install casing into the borehole.
The cost-effectiveness not only takes into consideration the
resources needed to install the casing, but also the amount of time
required.
[0021] Other objects and advantages of the invention will appear
from the following description.
SUMMARY OF THE PREFERRED EMBODIMENTS
[0022] The preferred embodiments provide an improved method and
apparatus for movement of equipment in passages. Specifically, the
embodiments provide improved methods and apparatus for moving
casing within a borehole.
[0023] One preferred embodiment includes an apparatus and method
for moving casing into a borehole using a propulsion system. The
propulsion system includes a housing having an upstream section
with a traction module and a downstream section with a traction
module. The traction modules are each connected to a ram mounted in
a cylinder within one of the housing sections for propelling the
housing up and down the borehole. In operation, one of the traction
modules expands to engage the borehole wall ID, whether it be a
cased or open borehole, while the hydraulic ram forces the housing
downhole as the other traction module moves to the other end of its
housing section in preparation for actuating its ram to move the
housing farther downhole.
[0024] The propulsion system is not only capable of movement within
the inner diameter ("ID") of the casing string, but also operates
within of the inner diameter of the open borehole. Extending from
the uphole end of the propulsion system is a power fluid coiled
tubing. This tubing allows fluid-flow from a surface power fluid
supply that powers the propulsion system as it travels downhole.
The power fluid returns to the surface through the annulus formed
by the casing string and cased or open borehole wall.
[0025] The upstream end of the propulsion system includes an
annular shoulder projecting radially from the outside of the
propulsion system. The lower, or downhole, terminal end of the
casing string to be engaged by the propulsion system includes a
corresponding annular collar extending radially inward on the ID of
the casing. The outer diameter ("OD") of the propulsion system
shoulder is greater than the ID of the casing collar such that the
housing of the propulsion system can pass through the casing
collar, but the propulsion system shoulder cannot. In other words,
the propulsion system shoulder engages the casing collar and bears
against the casing collar to pull the casing string downhole.
[0026] To install the casing string, the casing string is first
inserted into the borehole as far as possible using conventional
methods such as gravity feeding or "floating". Once the casing
string cannot proceed further downhole, the propulsion system is
inserted into the uphole end of the casing string at the surface
with the power fluid coiled tubing attached. The propulsion system
travels through the casing string until the propulsion system
reaches the downhole end of the casing string. As the propulsion
system reaches the end of the casing string, the propulsion system
housing passes through the casing collar until the propulsion
system shoulder on the rear of the propulsion system engages the
casing collar on the end of the casing string. After the shoulder
engages the collar, as the propulsion system travels further
downhole, it pulls the casing string down through the borehole
until the downhole end of the casing reaches the desired depth. The
propulsion system is then retrieved either by reversing the
propulsion system to travel back through the casing string to the
surface or by rewinding the power fluid coiled tubing onto a
powered tubing spool.
[0027] In another preferred embodiment, the casing string is used
to supply the power fluid to the propulsion system so as to avoid
the need for a power fluid coiled tubing. Further, a disposable
propulsion system would be used whereby the propulsion system would
be left downhole once the borehole has been completely drilled and
the casing string installed. It should be appreciated that the
propulsion system would be made inexpensively since it would not be
retrieved. The engagement between the casing collar and propulsion
system shoulder would provide an adequate seal so as to direct the
power fluid through the propulsion system and drive the system. The
pressure of the power fluid against the propulsion system shoulder
assists in the sealing engagement. This preferred embodiment
otherwise operates similarly to the first preferred embodiment and
saves the cost of a power fluid coiled tubing and the time required
to retrieve the propulsion system from the borehole.
[0028] Various methods may be used to add a new section of casing
to the casing string once the casing string travels far enough to
add another section of casing to the casing string at the surface.
One method includes disconnecting the power fluid coiled tubing
from the fluid pump each time a new casing section is to be added.
After the power fluid coiled tubing is disconnected, it is fed
through the downhole end of the next length of casing. The casing
section is then attached to the uphole end of the casing in the
borehole. The power fluid coiled tubing is then re-connected to the
fluid pump and the installation process is re-commenced. Another
method includes threading the power fluid coiled tubing through
multiple casing sections to later be added to the casing string. As
new casing sections are required, the next casing section threaded
onto the power fluid coiled tubing is attached to the casing
string. If all of the threaded casing sections have been added to
the casing string, then the power fluid coiled tubing is
disconnected to thread additional casing sections. Still another
method includes removing the propulsion system from the borehole to
the surface each time it is necessary to add a new casing section
and then re-inserting the propulsion system into the casing string
to travel back downhole to continue pulling the casing string into
the borehole. It should be appreciated that other methods may be
used to add new casing sections.
[0029] New casing sections are added until the casing string
reaches the bottom of the newly drilled borehole. Once the casing
is installed in the borehole, the propulsion system is then
retrieved back uphole, through the casing string to the surface
where it is removed from the casing string.
[0030] Still another preferred embodiment includes installing
multiple casing strings into a newly drilled borehole. This
embodiment is particularly advantageous when the horizontal portion
of the borehole is very long and the propulsion system cannot
install the entire length of the casing string in the new borehole.
In this embodiment multiple lengths of casing string are installed
such as for example a first casing length and a second casing
length. The second casing length would have a smaller diameter than
the first length so that the second casing length would pass
through the first casing length.
[0031] The first casing length includes a downhole connection on
its lower terminal end which also serves as a casing collar. The
second casing length, in addition to the casing collar described
above, also includes a snap collar or other similar uphole
connection on the upstream end of the second casing length. The
propulsion system shoulder bears against the casing collar on the
lower end of the first casing length to pull the first casing
length downhole. After the first casing length has reached the
desired depth, the propulsion system is then pulled out of the
borehole.
[0032] The second casing length is then run into the borehole using
the propulsion system. The propulsion system shoulder bears on the
casing collar on the lower end of the second casing length. The
propulsion system pulls the second casing length through the first
casing length until the second casing length reaches its desired
depth and the uphole connection on the second casing length
stab-connects with the downhole connection on the downstream end of
the first casing length, thus connecting the first casing length
with the second casing length. The propulsion system is then
retrieved from the borehole and an additional casing length
installed as necessary. This process is repeated until the entire
horizontal borehole is lined with a length of casing. Thus, the
casing string is run in lengths until the all the casing has been
installed.
[0033] Thus, the preferred and alternative embodiments comprise a
combination of features and advantages that enable them to overcome
various problems of prior devices. The various characteristics
described above, as well as other features, will be readily
apparent to those skilled in the art upon reading the following
detailed description of the preferred and alternative embodiments,
and by referring to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] For a more detailed description of the preferred and
alternative embodiments, reference will now be made to the
accompanying drawings, wherein:
[0035] FIG. 1 is a schematic view of a conventional land well
casing architecture;
[0036] FIG. 2 is a schematic view of one preferred embodiment of a
propulsion system engaged with an end of a casing string;
[0037] FIG. 3 is a cross-sectional view of the propulsion system of
FIG. 2;
[0038] FIG. 4 is a cross-sectional view taken at plane 4-4 in FIG.
3 showing one of the traction modules;
[0039] FIG. 5 is a schematic view of another preferred embodiment
of the propulsion system using the casing string as the means for
providing power fluid to the propulsion system; and
[0040] FIG. 6 is a schematic view of a still another preferred
embodiment of a propulsion system engaged with an end of a casing
length that is to be joined with the a previously installed casing
length.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0041] While preferred embodiments of this invention are shown and
described, modifications thereof can be made by one skilled in the
art without departing from the spirit or teaching of this
invention. The embodiments described herein are exemplary only and
are not limiting. Many variations and modifications of the
apparatus and methods are possible and are within the scope of the
invention. Accordingly, the scope of protection is not limited to
the embodiments described herein, but is only limited by the claims
that follow, the scope of which shall include all equivalents of
the subject matter of the claims.
[0042] In the description that follows, like parts are marked
throughout the specification and drawings with the same reference
numerals, respectively. The drawing figures are not necessarily to
scale. Certain features may be shown in exaggerated in scale or in
somewhat schematic form and some details of conventional elements
may not be shown in the interest of clarity and conciseness. For
example, standard fluid sealing techniques, such as the use of
annular O-ring seals, and threaded connections may be depicted but
not described in detail herein, as such techniques are well known
in the art. As such, construction details are not important to
operation of the embodiments, and are well understood by those of
skill in the art, they will not be discussed here. In using the
terms "above", "up", "upward", "uphole" or "upper" with respect to
a member in the well bore, such member is considered to be at a
shorter distance from the surface through the bore hole than
another member which is described as being "below", "down",
"downward", "downhole", or "lower". It should also be appreciated
that the use of the term "casing" throughout this application also
includes liners or any other form of tubular member.
[0043] Referring initially to FIG. 1, a typical well 100 is shown.
The well 100 includes sections of structural casing 102 extending
into concentric boreholes 104 with each of the structural casing
102 having decreasing diameters. The sections of structural casing
102 extend to varying depths according to the design of the well
100 and particularly to the different formations through which the
boreholes extend. Once the structural casing 102 is in place, a
further borehole 106 is drilled to the reservoir 108.
[0044] Directional drilling methods known in the art allow the well
to be drilled in a deviated direction from vertical to deviated.
This type of well is referred to as a "deviated" borehole. In
addition, the borehole can deviate from vertical to such an extent
as to run horizontally for some distance. This type of borehole is
referred to as a "horizontal" borehole. It should also be
appreciated that a borehole can have more than one deviation, or
curve, and can thus comprise any number shapes as it travels into
the earth. The well 100 includes a borehole 14 having a vertical
portion 110 and a deviated portion 112 with the deviated portion
112 having a horizontal portion 114. A completions casing 12 is
installed that extends from the surface 116 to the reservoir 108.
The completions casing 12 forms an annulus 40 with the wall of the
borehole.
[0045] Referring now to FIG. 2, one preferred embodiment includes
an apparatus 10 for installing casing 12 within borehole 14. The
apparatus 10 includes a propulsion system 16 having one end, such
as uphole end 17, attached to the lower end of a power fluid coiled
tubing 26. The upper end of the power fluid coiled tubing 26 is
attached to a power fluid pump (not shown) at the surface 116.
Power fluid coiled tubing 26 may be metal coiled tubing or
preferably composite coiled tubing 26. Power fluid coiled tubing 26
allows fluid-flow from the surface 116 to the propulsion system 16
that powers the propulsion system 16 as it travels within borehole
14. Propulsion system 16 includes a housing 20 with a flow bore 22
therethrough for the fluids flowing down through the flowbore 24 of
power fluid coiled tubing 26 extending from the uphole end 17 of
the propulsion system 16. The propulsion system 16 engages the
completion casing 12, as hereinafter decried, for propelling the
casing 12 downhole.
[0046] Referring now to FIGS. 3 and 4, there is shown a schematic
of a typical propulsion system 16. For self-propulsion, propulsion
system 16 becomes the prime mover and includes a downstream
packer-like traction module 28 and an upstream packer-like traction
module 30. It should be appreciated that the propulsion system 16
may include more than two traction modules. Housing 20 of
propulsion system 16 includes a downstream section 32 and an
upstream section 34.
[0047] As best shown in FIG. 4, there is shown a cross-section of
traction module 30. Because the traction modules 28, 30 are similar
in construction, a description of one traction module approximates
the description of the other. Traction module 30 includes steel
feet 36 around its outer circumference that may be expanded and
contracted into engagement with the wall 15 of borehole 14. A
plurality of flutes or longitudinal fluid flow passages 38 are
provided around the inner circumference of the steel bands forming
feet 36 to allow fluid to flow upstream through annulus 40 when
traction module 30 is expanded into engagement with the wall 15 of
borehole 14. The traction modules 28, 30 may have independently
inflatable, individual chambers, as hereinafter described in
detail, for expanding modules 28, 30 eccentrically with respect to
the housing 20.
[0048] Downstream housing section 32 includes a tubular cylinder 42
in which is disposed a hydraulic ram 44 on which is mounted
downstream traction module 28. Hydraulic ports 46, 48 are disposed
at the opposite ends of tubular cylinder 42 for applying hydraulic
pressure to ram 44. Hydraulic ports 50, 52 are disposed adjacent
downstream traction module 28 for expanding and contracting the
traction module in and out of engagement with the wall of borehole
12. It should be appreciated that upstream housing section 20 is
similar in construction and operation with cylinder 43, ram 45, and
ports 47, 49, 51, and 53. It should also be appreciated that
propulsion system 16 includes a series of valves using fluid
pressure for the actuation of rams 44, 45 and traction modules 28,
30 mounted on rams 44, 45, respectively.
[0049] The cycle of propulsion system 16 includes expanding
downstream traction module 28 into engagement with the interior
wall 15 of borehole 14 with the upstream traction module 30 in the
contracted and non-engaged position as shown in FIG. 3. Hydraulic
pressure is applied through hydraulic ports 48, thus applying
pressure to ram 44. As pressure is applied against ram 44, which is
stationary relative to the borehole 14 due to its attachment to
engaged traction module 28, housing 20 moves downhole. Hydraulic
fluid is simultaneously applied through hydraulic port 49 causing
contracted upstream traction module 30 to move forward on upstream
housing section 34. Upstream traction module 30 thus moves forward
simultaneously with housing 20 moving downhole. Once the downstream
traction module 28 reaches the upstream end of tubular cylinder 42,
it has completed its forward stroke and is contracted.
Simultaneously, upstream traction module 30 has now completed its
travel to the downstream end of tubular cylinder 43 and it is in
its reset position to start its downward stroke. Traction module 30
is then expanded into engagement with borehole 14. As hydraulic
pressure is applied through hydraulic port 47 and against upstream
ram 45, propulsion system 16 strokes downwardly. Simultaneously,
downstream traction module 28 is contracted and reset by applying
hydraulic pressure through upstream port 46. The cycle is then
repeated allowing the propulsion system 16 to move continuously
downstream in one fluid motion. Each stroke approximates the length
of housing sections 32, 34. It should be appreciated that the
propulsion system 16 is not only capable of movement within the
borehole 14, but also is capable of operating within the ID of the
structural casing 12 or any other casing already in place in the
borehole 14. The propulsion system 16 has this ability due to the
expansion and contraction of the traction modules 28, 30.
[0050] It should be appreciated that the hydraulic actuation may be
reversed whereby propulsion system 16 may be moved upstream in
borehole 14. In other words, propulsion system 16 can "walk" either
forward, downstream, or backward, upstream in borehole 14. It also
should be appreciated that although propulsion system 16 is shown
as being hydraulically actuated, it may also be operated
electrically with power being provided through power transmission
conductors.
[0051] It should also be appreciated that although the propulsion
system 16 has been described with two traction modules, the
propulsion system 16 may be configured with additional traction
modules, such as three traction modules, depending upon the
application.
[0052] Western Well Tool, Inc. manufactures a preferred propulsion
system having expandable and contractible upstream and downstream
traction modules mounted on a hydraulic ram and cylinder for
self-propelling drilling bits. The Western Well Tool propulsion
system is described in a European Patent Application PCT/US96/13573
filed Aug. 22, 1996 and published Mar. 6, 1997, Publication No. WO
97/08418, hereby incorporated herein by reference.
[0053] Other propulsion systems may be adapted for use with the
preferred embodiment. Other types of propulsion systems include an
inchworm by Camco International, Inc., U.S. Pat. No. 5,394,951,
hereby incorporated herein by reference and by Honda, U.S. Pat. No.
5,662,020, hereby incorporated herein by reference. See also U.S.
Pat. No. 3,799,277, hereby incorporated herein by reference. Also,
robotic propulsion systems are produced by Martin Marietta Energy
Systems, Inc. and are disclosed in U.S. Pat. Nos. 5,497,707 and
5,601,025, each hereby incorporated herein by reference. Another
company manufactures a propulsion system that it calls a "Helix".
See also "Inchworm Mobility--Stable, Reliable and Inexpensive," by
Alexander Ferwom and Deborah Stacey; "Oil Well Tractor" by
CSIRO-UTS of Australia; "Well Tractor for Use in Deviated and
Horizontal Wells" by Fredrik Schussler; "Extending the Reach of
Coiled Tubing Drilling (Thrusters, Equalizers, and Tractors)" by L.
J. Leising, E. C. Onyia, S. C. Townsend, P. R. Paslay and D. A.
Stein, SPE Paper 37656, 1997, all hereby incorporated herein by
reference. See also "Well Tractors for Highly Deviated and
Horizontal Wells", SPE Paper 28871 presented at the 1994 SPE
European Petroleum Conference, London, Oct. 25-27, 1994, hereby
incorporated herein by reference.
[0054] Referring again to FIG. 2, the upstream end 17 of the
propulsion system 16 includes an attachment member for attaching
the propulsion system 16 to the casing 12. In one preferred
embodiment, the propulsion system attachment member is an annular
shoulder 54 extending radially outward from the outside of uphole
end 17 of housing 20 of the propulsion system 16. The lower, or
downhole, end of casing 12 also includes an attachment member. In
one preferred embodiment, the casing attachment member is an
annular collar 56 on the ID of the casing 12. The annular collar 56
has a inner diameter greater than the outer diameter of housing 20
such that lousing 20 will pass through the annular collar 56. The
OD of the propulsion system shoulder 54 is greater than the ID of
the casing collar 56 such that the housing 20 of propulsion system
16 can pass through the casing collar 56, but the propulsion system
shoulder 54 cannot such that propulsion system shoulder 54 bears
against casing annular collar 56.
[0055] It should be appreciated that casing annular collar 56 may
be affixed to the end of casing 12 in various manners. In one
embodiment, annular collar 56 is part of a sub 57 threaded onto the
lowermost section of casing 12 making up the casing string. Annular
collar 56 must be strong enough to withstand the forces to be
applied to it by propulsion system 16 to pull the casing string
into the borehole 14.
[0056] It should be appreciated that the annular shoulder 54 on
propulsion system 16 may be removable from housing 20. For example,
annular shoulder 54 may be threaded onto housing 20. Another
example includes mounting the annular showered 54 on the connection
between the power fluid coiled tubing 26 and housing 20 of the
propulsion system 16. This will allow annular shoulders 54 with
different outside diameters to be mounted on propulsions system 16
to accommodate the size of the casing 12 being installed.
[0057] In accordance with the preferred methods of operation, the
casing string 12 is first installed into the borehole 14 as far as
possible using conventional methods such as gravity feeding or
"floating". Once the casing string 12 cannot proceed further
downhole, the propulsion system 16 is inserted into the uphole end
of the casing string 12 at the surface 116 with the power fluid
coiled tubing 26 attached. The propulsion system 16 travels through
the interior of the casing string 12 until the propulsion system 16
reaches the downhole end 18 of the casing string 12. As the
propulsion system 16 reaches the end 18 of the casing string 12,
the propulsion system housing 20 passes through the ID of casing
collar 56 until the propulsion system shoulder 54 engages the
casing collar 56. After the shoulder 54 engages the collar 56, as
the propulsion system 16 travels further downhole, it pulls the
casing string 12 further down through the borehole 14. This is
particularly advantageous in installing the casing string 12 in a
highly deviated borehole 112 and most advantageous in a horizontal
portion 114 of the borehole 14.
[0058] The propulsion system 16 then travels further downhole,
pulling the casing string 12 down through the borehole 14 until the
downhole end 18 of the casing string 12 reaches the desired depth.
The propulsion system 16 is then retrieved either reversing the
propulsion system 16 to travel back through the casing string 12 to
the surface 116 or by rewinding the power fluid coiled tubing 26
onto a powered tubing spool.
[0059] Referring now to FIG. 5, there is shown another preferred
embodiment. In this embodiment, the casing string 12 is used to
supply the power fluid to the propulsion system 16 so as to avoid
the need for a power fluid coiled tubing. Further, a disposable
propulsion system would be used whereby the propulsion system 16
would be left downhole once the borehole 14 has been completely
drilled and the casing string 12 installed. It should be
appreciated that the propulsion system 12 would be made
inexpensively because it would not be retrieved. The engagement at
55 between the casing collar 56 and propulsion system shoulder 54
would provide an adequate seal so as to direct the power fluid 62
through the propulsion system 16 and drive the system. The pressure
of the power fluid 62 against the propulsion system shoulder 54
assists in the sealing engagement at 55. This preferred embodiment
otherwise operates similarly to the first preferred embodiment and
saves the cost of a power fluid coiled tubing and the time required
to retrieve the propulsion system from the borehole.
[0060] Once the casing string 12 travels far enough to add on more
sections of casing, the propulsion system 16 stops, reverses, and
then travels back uphole to the surface 108 where it is retrieved
from the casing string 12. As many sections of casing as can be
handled on the surface 108 are then added to the casing string 12.
The propulsion system 16 is then re-inserted into the casing string
12 and the process is repeated until the casing string 12 reaches
the reservoir 106. Once the casing 12 is installed in the borehole
14, the propulsion system 16 then travels uphole, back through the
casing 12 to the surface 108 where it is retrieved from the casing
string 12.
[0061] Various methods may be used to add a new section of casing
to the casing string 12 once the casing string 12 travels far
enough to add another section of casing to the casing string 12 at
the surface 116. One method includes disconnecting the power fluid
coiled tubing 26 from the fluid pump each time a new casing section
is to be added. After the power fluid coiled tubing 26 is
disconnected, it is fed through the downhole end of the next length
of casing 12. The casing section is then attached to the uphole end
of the casing string 12 in the borehole 14. The power fluid coiled
tubing 26 is then re-connected to the fluid pump and the
installation process is re-commenced.
[0062] Another method includes threading the power fluid coiled
tubing 26 through multiple casing sections to later be added to the
casing string 12. As new casing sections are required, the next
casing section, threaded onto the power fluid coiled tubing 26, is
attached to the casing string 12. If all of the threaded casing
sections have been added to the casing string 12, then the power
fluid coiled tubing 26 is disconnected to thread additional casing
sections.
[0063] Still another method includes removing the propulsion system
16 from the borehole 14 to the surface 116 each time it is
necessary to add a new casing section and then re-inserting the
propulsion system 16 into the casing string 12 to travel back
downhole to continue pulling the casing string 12 into the borehole
14. It should be appreciated that other methods may be used to add
new casing sections.
[0064] New casing sections are added until the casing string 12
reaches the bottom of the newly drilled borehole 14. Once the
casing 12 is installed in the borehole 14, the propulsion system 16
is then retrieved back uphole, through the casing string 12 to the
surface 116 where it is removed from the casing string 12.
[0065] Referring now to FIG. 6, still another preferred embodiment
includes installing multiple casing strings into a newly drilled
borehole. This embodiment is particularly advantageous when the
horizontal portion of the borehole is very long and the propulsion
system cannot install the entire length of the casing string in the
new borehole at one time. In this embodiment, multiple lengths,
such as first casing length 58 and second casing length 60, of the
casing string are installed. The second casing length 60 has a
smaller diameter than the first length 58 so that the second casing
length 60 can pass through the first casing length 58.
[0066] The first casing length 58 includes a downhole connection 64
on its lower terminal end 66, which also serves as a casing collar.
The second casing length 60, in addition to the casing collar
described above, also includes a snap collar or other similar
uphole connection 68 on the upstream end 70 of the second casing
length 60.
[0067] In operation, initially the first casing length 58 is
installed in the borehole 14 as previously described. The
propulsion system shoulder 54 bears against the casing collar
connection 64 on the lower end 66 of the first casing length 58 to
pull the first casing length 58 downhole. After the first casing
length 58 has reached the desired depth, the propulsion system 16
is then pulled out of the borehole 14.
[0068] The annular shoulder 54 on propulsion system 16 may be
changed to an annular shoulder 54 which has a smaller outside
diameter to accommodate the smaller diameter second casing length
60. The second casing length 60 is then run into the borehole 14
through the first casing length 58 using the propulsion system 16.
The propulsion system shoulder 54 bears on the casing collar 56 on
the lower end of the second casing length 60. The propulsion system
16 pulls the second casing length 60 through the first casing
length 58 until the second casing length 60 reaches its desired
depth and the uphole connection 68 on the second casing length 60
stab-connects with the downhole connection 64 on the downstream end
66 of the first casing length 58, thus connecting the first casing
length 58 with the second casing length 60. The propulsion system
16 is then retrieved from the borehole 18 and an additional casing
length is installed as necessary. This process is repeated until
the entire horizontal borehole 114 is lined with a length of
casing. Thus, the casing string is run in lengths until the all the
casing has been installed.
[0069] While preferred embodiments of the invention have been shown
and described, modifications can be made by one skilled in the art
without departing from the spirit of the invention.
* * * * *