U.S. patent application number 10/459387 was filed with the patent office on 2004-12-16 for method for using expandable tubulars.
Invention is credited to Cameron, John, Whitelaw, Calum.
Application Number | 20040251033 10/459387 |
Document ID | / |
Family ID | 33510810 |
Filed Date | 2004-12-16 |
United States Patent
Application |
20040251033 |
Kind Code |
A1 |
Cameron, John ; et
al. |
December 16, 2004 |
Method for using expandable tubulars
Abstract
An improved method for completing wells, such as hydrocarbon
wells, is provided. In one aspect, methods are provided for
deploying an expandable tubular, such as an expandable sand screen,
in a hydrocarbon well. According to methods of the present
invention, a sand screen is lowered into a wellbore. Thereafter,
cement is injected into the wellbore so as to place a column of
cement in the annular region between the tubular and the
surrounding formation. The cement is then treated so as to imbue
greater permeability and/or porosity characteristics. The cement
serves to reinforce the sand screen, providing it with both
improved physical strength and improved sand filtering ability. At
the same time, the sand screen serves to reinforce and strengthen
the cement sheath placed in the wellbore.
Inventors: |
Cameron, John; (The
Woodlands, TX) ; Whitelaw, Calum; (Aberdeenshire,
GB) |
Correspondence
Address: |
MOSER, PATTERSON & SHERIDAN, L.L.P.
Suite 1500
3040 Post Oak Blvd.
Houston
TX
77056
US
|
Family ID: |
33510810 |
Appl. No.: |
10/459387 |
Filed: |
June 11, 2003 |
Current U.S.
Class: |
166/382 ;
166/206; 166/207 |
Current CPC
Class: |
E21B 43/086 20130101;
E21B 43/103 20130101; E21B 43/025 20130101; E21B 43/108 20130101;
E21B 43/105 20130101 |
Class at
Publication: |
166/382 ;
166/206; 166/207 |
International
Class: |
E21B 023/00 |
Claims
1. A method for using an expandable tubular within a wellbore,
comprising the steps of: running the tubular into the wellbore;
locating the tubular in the wellbore adjacent a producing zone;
expanding the tubular radially outward along a desired length; and
placing cement in an annular region defined by the area between the
expanded tubular and the surrounding wellbore.
2. The method of claim 1, wherein the wellbore along the producing
zone is an open hole wellbore, allowing fluid communication between
an earth formation at the producing zone and the expanded
tubular.
3. The method of claim 1, wherein the wellbore along the producing
zone is cased with a string of perforated casing, allowing fluid
communication between an earth formation at the producing zone and
the expanded tubular.
4. The method of claim 1, wherein the cement is a permeable and
porous cement that permits fluids to flow from the earth formation
to the expanded tubular.
5. The method of claim 4, wherein the method is conducted to remedy
a failed completion.
6. The method of claim 4, wherein the step of placing cement in the
annular region is performed by injecting cement through a tubular
string, and then forcing a portion of the injected cement around
the bottom of the expanded tubular and up into the annular
region.
7. The method of claim 4, further comprising the step of: removing
substantially all of any cement disposed within the expanded
tubular, leaving a cylindrical cement column in the annular region
around the tubular.
8. The method of claim 7, wherein the step of removing
substantially all of the cement disposed within the tubular is
performed by drilling out the cement after it has substantially
cured.
9. The method of claim 4, wherein the tubular is an expandable sand
screen.
10. The method of claim 9, further comprising the step of:
injecting a treating fluid into and through the sand screen in
order to contact and treat the cement column, the treating fluid
increasing the permeability of the set cement.
11. The method of claim 10, wherein the step of injecting the
treating fluid is performed after the step of expanding the sand
screen.
12. The method of claim 4, wherein the cement is comprised of a
hydraulic cement, a particulate cross-linked gel containing an
internal breaker which after time causes said gel to break into a
liquid, and water present in an amount sufficient to form a
slurry.
13. The method of claim 12, further comprising the step of:
injecting a treating fluid into and through the sand screen in
order to contact and treat the cement column, the treating fluid
increasing the permeability of the set cement; and wherein the
cement is further comprised of a particulate solid that is soluble
in the presence of the treating fluid.
14. The method of claim 1, wherein the step of expanding the
tubular is performed by using an expander tool, the expander tool
comprising a tapered cone portion urged axially within the
tubular.
15. The method of claim 14, wherein the expander tool further
comprises a hydraulically actuated tool portion.
16. A method for forming a permeable cement sand barrier in a
wellbore, the wellbore having a wall, the method comprising the
steps of: deploying a perforated expandable tubular at a selected
depth; expanding the tubular; injecting a permeable cement
composition into the annulus formed between the wall of the
wellbore and the perforated expandable tubular; and allowing the
cement composition to set.
17. The method of claim 16, wherein the permeable cement defines a
composition comprised of: a hydraulic cement, a particulate
cross-linked gel containing an internal breaker which after time
causes the gel to break into a liquid, allowing the particulate
cross-linked gel containing the internal breaker to break so that
vugs and channels are formed in the cement composition as the
cement composition sets; and water present in an amount sufficient
to form a slurry.
18. The method of claim 17, further comprising the step of:
allowing the particulate cross-linked gel containing the internal
breaker to break.
19. The method of claim 18, wherein the cement composition further
comprises an acid soluble particulate solid; and the method further
comprises the step of introducing an acid solvent into the
perforated pipe whereby the acid solvent flows through the
perforations in the pipe and into contact with the set cement
composition so as to dissolve the acid soluble particulate solid,
thereby creating channels for the flow of hydrocarbons
therethrough.
20. The method of claim 19, wherein the cement composition further
comprises: a gas present in an amount sufficient to form a foam;
and a mixture of foaming and foam stabilizing surfactants.
21. The method of claim 16, wherein the perforated expandable
tubular is an expandable sand screen.
22. A method for using an expandable tubular within a wellbore,
comprising the steps of: running the tubular into the wellbore;
locating the tubular in the wellbore adjacent a producing zone;
placing cement in an annular region defined by the area between the
tubular and the surrounding wellbore; and expanding the tubular
radially outward along a desired length before the cement has
cured.
23. The method of claim 22, wherein the expandable tubular is an
expandable sand screen.
24. The method of claim 22, further comprising the step of: hanging
the expandable sand screen within the wellbore before the step of
expanding the sand screen radially is conducted.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to methods for completing
wells, such as hydrocarbon and water wells. More specifically, the
present invention provides methods for deploying an expandable
tubular in a hydrocarbon well. More particularly still, methods are
provided for placing an expandable perforated tubular, such as a
sand screen, within a wellbore having a permeable cement.
[0003] 2. Description of Related Art
[0004] Hydrocarbon wells are typically formed with a central
wellbore that is supported by steel casing. The steel casing lines
the borehole formed in the earth during the drilling process. This
creates an annular area between the casing and the borehole, which
is filled with cement to further support and form the wellbore.
[0005] Some wells are produced by perforating the casing of the
wellbore at selected depths where hydrocarbons are found.
Hydrocarbons migrate from the formation, through the perforations,
and into the cased wellbore. In some instances, a lower portion of
a wellbore is left open, that is, it is not lined with casing. This
is known as an open hole completion. In that instance, hydrocarbons
in an adjacent earth formation migrate directly into the wellbore
where they are subsequently raised to the surface, typically
through an artificial lift system.
[0006] Open hole completions carry the potential of higher
production than cased hole completions. Open hole completions are
frequently utilized in connection with horizontally drilled
boreholes. However, open hole completions present various risks
concerning the integrity of the open wellbore. In that respect, an
open hole leaves aggregate material, including sand, free to invade
the wellbore. Sand production can result in premature failure of
artificial lift and other downhole and surface equipment. Sand can
build up in the borehole and tubing to obstruct fluid flow.
Particles can compact and erode surrounding formations to cause
liner and casing failures. In addition, produced sand becomes
difficult to handle and dispose of at the surface. Ultimately, open
holes carry the risk of complete collapse of the formation into the
wellbore.
[0007] Heretofore, gravel packs have been utilized in wells to
preserve the integrity of the formed borehole, and to prevent the
production of formation sand. In gravel packing operations, a pack
of gravel, e.g., graded sand, is placed in the annulus between a
perforated or slotted liner or screen and the walls of the wellbore
in the producing interval. The resulting structure provides a
barrier to migrating sand from the producing formation while
allowing the flow of produced fluids.
[0008] While gravel packs inhibit the production of sand with
formation fluids, they often fail and require replacement due, for
example, to the deterioration of the perforated or slotted liner or
screen as a result of corrosion or the like. In addition, the
initial installation of a gravel pack adds considerable expense to
the cost of completing a well. The removal and replacement of a
failed gravel pack is even more costly.
[0009] To better control particle flow from unconsolidated
formations, an improved form of well screen has been recently
developed. The well screen is known as an expandable sand screen,
or "ESS.RTM. screen." The ESS.RTM. system is run into the wellbore
at the lower end of a liner string and is expanded into engagement
with the surrounding formation, thereby obviating the need for a
separate gravel pack. In general, the ESS.RTM. system is
constructed from three composite layers, including a slotted base
pipe, a protective, perforated outer shroud, and an intermediate
filter media. The filter media allows hydrocarbons to invade the
wellbore, but filters sand and other unwanted particles from
entering. Both the base pipe and the outer shroud are expandable,
with the woven filter being arranged over the base pipe in sheets
that partially cover one another and slide across one another as
the sand screen is expanded.
[0010] FIG. 1 presents a section view showing a wellbore 40. The
wellbore 40 is lined with a string of casing 42. The casing 42
separates the interior of the wellbore 40 from the surrounding
earth formation 48. An annular area is left between the casing 42
and the earth formation 48 and is filled with cement 46, as is
typical in a well completion. Extending downward below the cased
portion of the wellbore 40 is an open hole portion 50. The earth
formation 48 forms the wall of the wellbore for the open hole
portion 50.
[0011] Disposed in the open hole portion 50 of the wellbore 40 is
an expandable tubular 20. In the view of FIG. 1, the tubular 20
represents a sand screen 20, such as Weatherford's ESS.RTM. sand
screen. The expandable sand screen 20 is hung within the wellbore
40 from a hanging apparatus 32. In some instances, the hanging
apparatus 32 is a packer. In the depiction of FIG. 1, the hanging
apparatus 32 is a liner 30 and liner hanger 32.
[0012] A production tubular 44 is also seen placed in the wellbore
40 of FIG. 1. The production tubular 44 extends from the surface
and into a top portion of the liner 30. A packer 34 is employed to
seal the annulus between the production tubular 44 and the liner
30.
[0013] Also depicted in FIG. 1 is an instrumentation line 62. The
optional instrumentation line 62 runs within an encapsulation 12
from the earth surface (not shown) along the production tubular 44.
The encapsulation 12 is secured to the production tubular 44 by
clamps, shown schematically at 18. Clamps 18 are typically secured
to the production tubular 44 approximately every ten meters. The
encapsulation 12 passes through the liner hanger 32 (or utilized
hanging apparatus), and extends downward to the top 21 of the sand
screen 20. In the arrangement shown in FIG. 1, the instrumentation
line 62 enters a recess (shown at 10 in FIG. 2) in the outer
diameter of the ESS.RTM. 20. Arrangements for the recess 10 are
described more fully in the pending application entitled "Profiled
Recess for Instrumented Expandable Components," having Ser. No.
09/964,034, which is incorporated herein in its entirety, by
reference. However, the instrumentation line 62 may also be housed
in a specially profiled encapsulation around the ESS.RTM. 20 which
contains arcuate walls. Arrangements for the encapsulation are
described more fully in the pending application entitled "Profiled
Encapsulation for Use With Expandable Sand Screen," having Ser. No.
09/964,160, which is also incorporated herein in its entirety, by
reference.
[0014] FIG. 2 presents a cross-section of a sand screen 20' within
an open hole completion wellbore 50'. The sand screen 20' is seen
within a surrounding formation 48. Three layers of the sand screen
20' are shown, representing a base pipe 22, a protective outer
shroud 26, and an intermediate filter media 24. Slots 23 are seen
within the base pipe 22 and the shroud 26. A recess 10 is seen
within the outer shroud 26 for receiving a pair of instrumentation
lines 62. In this arrangement, the instrumentation lines 62 are
housed within tubular casings 60.
[0015] In FIGS. 1 and 2, the sand screens 20, 20' are shown in
their run-in positions. However, the sand screens 20, 20' are
configured to be expandable. In this manner, the sand screens 20,
20' are expanded downhole against the adjacent formation 48 in
order to preserve the integrity of the formation 48 during
production. This step is presented in FIG. 3, which presents the
open wellbore 50 with the sand screen 20 having been expanded.
[0016] FIG. 4 presents the sand screen 20' of FIG. 2, in its
expanded state. Here, the sand screen 20' has been expanded into
radial frictional engagement with the surrounding formation 48.
Expansion of the sand screen 20' obviates the need for a gravel
pack, and allows for a larger i.d. within the production zone. A
more particular description of an expandable sand screen is
described in U.S. Pat. No. 5,901,789, which is incorporated by
reference herein in its entirety.
[0017] The expandable sand screens 20, 20' are expanded by an
expander tool 200. An example of an expander tool 200 as may be
used to expand a downhole tubular such as sand screen is seen in
FIG. 5. FIG. 5 presents a perspective view of an expander tool 200.
The expander tool 200 first comprises a conical portion, or "cone"
210. The cone 210 is urged through the inner bore of the sand
screen 20 by pushing down or pulling up on a connected working
string (not shown), or by otherwise translating the expander tool
200 such as through a downhole translation mechanism. The cone 210
has an outer diameter that is greater than the inner diameter of
the sand screen 20. As the cone is urged through the sand screen
20, both the inner and outer diameters of the sand screen 20 are
expanded.
[0018] The expander tool 200 of FIG. 5 also comprises a
hydraulically actuated tool portion 220. The hydraulically actuated
portion 220 defines a body 222 having a plurality of radially
outward extending roller members 216. The roller members 216 are
urged outwardly away from the tool body 222 in response to fluid
pressure applied within the perforated inner mandrel of the tool
200.
[0019] When it is desired to expand a tubular downhole, the
expander tool 200 is translated axially (such as by raising and/or
lowering the working string from the surface) along a desired
length. Where a sand screen 20 is used as the expandable tubular,
the expander tool 200 is translated along the length of the sand
screen 20 in order to expand the inner and outer diameters of the
screen 20. The sand screen components 22, 26 are stretched past
their elastic limit, thereby increasing the outer diameter of the
sand screen 20. In this way, the screen walls are placed closely
adjacent to the borehole wall in full compliance, even in an
irregular borehole.
[0020] In order to obtain a radial expansion of a downhole tubular
20, the expander tool 200 may also be rotated. This may be
accomplished in various ways, such as by rotating the working
string from the surface or by employing a downhole motor.
[0021] Using expander means such as tool 200, an expandable tubular
20 is subjected to outwardly radial forces that expand the diameter
of the surrounding tubular 20. It is understood, however, that
other types of expander tools exist for expanding an elongated
tubular body downhole. The description of the expander tool 200
shown in FIG. 5 is not intended to be a limitation as to how a sand
screen or other expandable tubular might be expanded in the methods
of the present invention.
[0022] The sand screens 20, 20' of FIGS. 1 and 2, while
representing an improvement over prior gravel pack and sand screen
devices, nevertheless have limitations. For example, the ESS.RTM.
itself (if misapplied) is susceptible to the detrimental effects of
fluid and sand particles flowing therethrough, including erosion,
corrosion, and abrasion. In addition, the ESS.RTM. filter media 24
can become plugged with finer granular and clay particles if not
correctly installed in contact with the borehole wall 48, i.e., in
"compliant expansion." Finally, the layers 22, 24, 26 of the
ESS.RTM. have limitations in terms of physical strength. In certain
extreme cases where producing formations and wellbores are unstable
or irregular and difficult to obtain a competent gravel pack, it
may also be difficult to obtain fully compliant expandable screen
installation. Therefore, it is desirable to support the ESS.RTM.
system by injecting a thin cement column therearound. The cement
sheath can cater for very large dimensional irregularities and,
coupled with mechanical tubular support, can further stabilize the
formation/wellbore.
[0023] It is known to employ a column of porous and permeable
cement as a substitute for a gravel pack. U.S. Pat. No. 6,390,195
issued to Nguyen in May of 2002 provides a method of forming a
permeable cement sand screen in a wellbore adjacent to a fluid
producing zone. Similarly, U.S. Pat. Nos. 6,202,751 and 6,364,945,
issued in 2001 and 2002 respectively, to Chatterji, present
compositions for such a permeable cement sand screen. The method of
the '195 patent includes the use of a perforated pipe within the
wellbore at the producing zone. However, the pipe is not expanded,
nor is it slotted. The use of slotted expandable pipe affords a
significantly improved inflow area to the completion which aids
fluid flow and thereby increases the economic benefit to the
installation.
[0024] Accordingly, a need exists for a method for completing a
wellbore wherein an expandable sand screen is placed adjacent a
production zone, and is assisted by a column of permeable granular
material.
SUMMARY OF THE INVENTION
[0025] An improved method for completing wells, such as hydrocarbon
and water wells, is provided. According to methods of the present
invention, an expandable, perforated tubular, such as a sand screen
or a pre-slotted liner, is lowered into a wellbore. Thereafter,
cement is injected into the wellbore so as to place a column of
cement in the annular region between the tubular and the
surrounding formation.
[0026] In one aspect, the expandable tubular, e.g., sand screen, is
expanded before cement is injected into the annular region. The
tubular is not expanded into complete frictional engagement with
the surrounding formation, but an annular region is preserved. In
another aspect, the cement is injected into the annular region
before the tubular is expanded. In this arrangement, the expansion
operation is conducted before the cement is completely cured. In
either aspect, a thin cylinder of cement is formed around the
expandable tubular.
[0027] After the sand screen has been expanded and the cement
injected, the cement is cleaned out of the bore of the sand screen.
In one aspect, this is accomplished by drilling the cement out of
the bore. In another aspect, a treating fluid, e.g., an acid, is
injected into the wellbore at the depth of the sand screen after
the cement has been drilled out of the sand screen. The treating
fluid imbues permeability and/or porosity characteristics to the
cement, thereby permitting the flow of hydrocarbons
therethrough.
[0028] The cement serves to reinforce the expandable tubular,
providing it with both improved physical strength and improved sand
filtering ability. At the same time, the sand screen (or other
expandable tubular) serves to reinforce the cement after it has
cured. The use of cement in connection with the deployment of an
expandable sand screen may be done in either an open hole
completion, or in a cased wellbore. The use of cement in connection
with an expandable sand screen may also be used to repair failed
sand control completions within a wellbore.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] So that the manner in which the above recited features of
the present invention, and other features contemplated and claimed
herein, are attained and can be understood, a more particular
description of the invention, briefly summarized above, may be had
by reference to the appended drawings (FIGS. 7A through 8F). It is
to be noted, however, that the drawings illustrate only typical
embodiments of this invention and are therefore not to be
considered limiting of its scope, for the invention may admit to
other equally effective embodiments.
[0030] FIG. 1 presents a cross-sectional view of a wellbore. An
expandable sand screen has been deployed in the wellbore. The sand
screen has not yet been expanded.
[0031] FIG. 2 provides a cross-sectional view of an expandable sand
screen. The sand screen is shown within an open hole, in its
unexpanded state.
[0032] FIG. 3 presents the wellbore of FIG. 1, with the sand screen
having been expanded into contact with the surrounding earth
formation.
[0033] FIG. 4 demonstrates a cross-sectional view of an expandable
sand screen, with the sand screen having been radially
expanded.
[0034] FIG. 5 provides a perspective view of an expander tool as
might be used in the methods of the present invention.
[0035] FIG. 6A presents a cut-away view of an expandable sand
screen as might be used in the methods of the present invention.
The sand screen has not been expanded. Parts of the sand screen are
exploded apart for clarity.
[0036] FIG. 6B presents the expandable sand screen of FIG. 6A,
incorporated into a run-in string and in series with completion
tools. Here, the sand screen has been expanded by a tapered
cone.
[0037] FIGS. 7A-7E present steps for deploying a sand screen in
accordance with one of the methods of the present invention. In
each of these drawings, a cross-sectional view of a sand screen
within a wellbore is provided.
[0038] In FIG. 7A, the sand screen has been run into the wellbore.
The sand screen has not yet been expanded.
[0039] In FIG. 7B, the sand screen is being radially expanded along
its length. In this arrangement, a tapered cone is being used as
the expander tool.
[0040] FIG. 7C shows cement being squeezed up the annular region
defined by the sand screen and the surrounding formation.
[0041] The expanded sand screen is again shown in the view of FIG.
7D. Here, the expander tool has been removed from the wellbore, and
the working string has been reintroduced into the wellbore with a
drill bit at the lower end. The drill bit is shown drilling out
cement deposited or left inside the sand screen.
[0042] FIG. 7E presents the wellbore of FIG. 7A having been
completed. The drill bit is removed from the wellbore, and fluids
are being produced through the cement column and through the sand
screen. Arrows depict the flow of fluids, e.g., hydrocarbons, into
the wellbore.
[0043] FIGS. 8A-8E present steps for deploying a sand screen in
accordance with another of the methods of the present invention. In
each of these drawings, a cross-sectional view of a wellbore is
again seen. Here, the wellbore is cased.
[0044] In FIG. 8A, a string of casing is shown within the wellbore.
The casing string has been perforated.
[0045] FIG. 8B demonstrates a sand screen being run into the
wellbore of FIG. 8A. The sand screen is located at a depth that
traverses the perforated zone. In this arrangement, a mule shoe at
the lower end of the sand screen rests at the bottom of the
borehole. An expander tool is temporarily attached at the top end
of the sand screen. The sand screen has not yet been expanded
[0046] In FIG. 8C, the sand screen is being radially expanded along
its length. In this arrangement, a tapered cone is again being used
as the expander tool. A packer is seen set above the sand
screen.
[0047] FIG. 8D shows cement being squeezed up the annular region
defined by the sand screen and the surrounding formation.
[0048] The expanded sand screen is shown in the view of FIG. 8E.
The cone has been removed from the wellbore, and the working string
has been reintroduced into the wellbore, with a drill bit at the
lower end. The drill bit is shown drilling out cement inside the
sand screen.
[0049] FIG. 8F presents the wellbore of FIG. 8B having been
completed. The drill bit is removed from the wellbore, and fluids
are being produced through the cement column and through the sand
screen. Arrows depict the flow of fluids, e.g., hydrocarbons, into
the wellbore.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0050] FIG. 6A presents a more detailed view of an expandable sand
screen 100 as might be used in the methods of the present
invention. FIG. 6A is a cut-away view taken along the longitudinal
axis of the tool 100. The outer protective shroud 126 is seen
around the sand screen 100, while the inner base pipe 122 is seen
along the cut-away portion of the drawing. A filtration media 124
is disposed between the outer shroud 126 and the base pipe 122. In
the view of FIG. 6A, the filtration media 124 is seen only through
the slotted outer shroud 126.
[0051] In the arrangement shown in FIG. 6A, the expandable sand
screen 100 defines three distinct portions: (1) a top connector
110; (2) one or more expandable sand screen joints 120; and (3) a
bottom connector 130. The top connector 110, the sand screen joint
120, and the bottom connector 130 are exploded apart for
clarity.
[0052] First, the top connector 110 serves to connect the sand
screen joints 120 to a working string (such as the drill string
shown at 70 in FIGS. 7A-7E). In some instances, a blank pipe (not
shown) is placed between the top connector 110 and the working
string. The top connector 110 includes an upward stub Acme box
connection member 112 at its top end. The top connector 110 also
has a male threaded connection member 114 at its lower end.
Intermediate the upper 112 and lower 114 connectors, the top
connector 110 has a body 116 having a pre-formed shape. The body
126 is configured to receive and house an expander tool, such as
tool 200 shown in FIG. 5, during run-in.
[0053] Before expansion operations are conducted, a suitable sized
expander tool 200 can be installed into the top connector 100 at
the job site. To retain the expander tool 200 in position, shear
screws (not shown) are installed through the expander tool's body
202. Thus, the expander tool 200 is releasably connected to the top
connector 100.
[0054] Second, one or more sand screen joints 120 are provided.
ESS.RTM. joints are typically provided in 38 foot lengths. As
noted, the ESS.RTM. joints 120 are comprised of three layers, to
wit, a slotted steel tube known as a "base pipe" 122, overlapping
layers of filtering membrane, i.e., "an intermediate filter media"
124, and a pre-slotted steel plate 126 wrapped around the base pipe
122 and the filter media 124. The filter media 124 allows
hydrocarbons to invade the wellbore, but filters sand and other
unwanted particles from entering.
[0055] The sand screen joints 120 are configured to be expandable.
Expansion is achieved either by using a compliant expander tool, by
passing a tapered cone through the inside of the joint 120, or by
using an expander tool that incorporates both features, such as
tool 200 shown in FIG. 5. During the expansion process, both inner
122 and outer 126 layers of the joints 120 are plastically deformed
to achieve the desired dimension. The overlapping filter membranes
124 slide over one another to accommodate the increase in
diameter.
[0056] Third, a bottom connector 130 is provided in the ESS.RTM.
100. The bottom connector 130 has a top end 132 that connects to
the bottom of the sand screen joint 120. The bottom connector 130
provides a positive location for receiving the expander tool 200
after the expansion process is completed. In one arrangement, the
expander tool 200 remains in the wellbore after the expansion
process is completed, with the working string being detachable from
the expander tool 200. In one aspect, the bottom connector 130
connects at a lower end 134 to a shoe assembly (seen at 180 in FIG.
6B).
[0057] In operation, the sand screen 100 is run into a wellbore at
the end of a working string. FIG. 6B presents the expandable sand
screen 100 of FIG. 6A, incorporated into a run-in string 70, and in
series with completion tools. The completion tools include a hanger
140, a packer 150, and a shoe assembly 180. The hanger 140 includes
slip members 144 having wickers for frictionally engaging a
surrounding casing string (not shown in FIG. 6B). The packer 150
includes a sealing element 154 for sealing engaging the surrounding
wellbore once the packer 150 is set. FIG. 6B also shows in somewhat
schematic fashion, a tapered cone 210 releasably held within the
sand screen 100. Here, the sand screen 100 has been expanded along
its length. Note again, though, that the methods of the present
invention are not limited by the type of expander tool used for the
expansion operation.
[0058] In some instances, the sand screen 100 is deployed in a
wellbore having an open hole completion. FIGS. 7A-7E present steps
for deploying a sand screen 100 in accordance with one of the
methods of the present invention. In each of these drawings, a
cross-sectional view of the sand screen 100 within an open hole
wellbore 40 is provided. Thus, the wellbore 40 has an open hole
portion 50. It is also understood that the sand screen 100 shown in
FIGS. 7A-7E is exemplary. The present methods are equally
applicable for other expandable tubulars, such as expandable casing
liners and alternative borehole liners.
[0059] In FIG. 7A, the sand screen 100 has been run into the
wellbore 40 at the end of a working string 70. In this respect, the
sand screen 100 is releasably attached to an expander tool 200'.
The expander tool 200', in turn, is attached to the lower end of
the working string 70. A liner hanger 140 is provided to hang the
sand screen 100 once it is lowered to the desired producing zone. A
packer 150 is also shown. It is understood, of course, that other
completion tools may be used, such as a run-in tool.
[0060] FIG. 7B presents the next step in the completion process. In
FIG. 7B, the liner hanger 140 and packer 150 have been set in the
wellbore 40. Axial stress has sheared the shear pins (not shown),
releasing the cone 200' from the top connector (shown as 110 in
FIG. 6A). This allows the cone 200' to move downward relative to
the expandable tubular 100. The cone 200' is moved downward at the
lower end of the working string 70. As the cone 200' is urged
downward, the expandable tubular 100 is radially expanded along its
length. The tubular 100 is not expanded into complete frictional
engagement with the surrounding formation 48, but an annular region
is preserved. In the arrangement of FIG. 7B, a tapered cone is
being used as the expander tool 200'. However, it is again
understood that the methods of the present invention are not
limited to the manner in which expansion is accomplished, or the
type of expander tool used.
[0061] FIG. 7C presents the next step in the completion process.
Here, cement 55 is being injected through the working string 70,
through the expander tool 200', and out of the mule shoe 180. The
cement 55 is then squeezed up the annular region defined by the
sand screen 100 and the surrounding formation wall 48. In this way,
a thin tubular column of cement 55 is placed in the open hole
portion 50 of the wellbore 40.
[0062] It is noted that the sand screen 100 in FIG. 7C is held in
tension during the cementing and expansion process. However, the
methods of the present invention are not limited to an arrangement
where the sand screen 100 (or other expandable tubular) is held in
tension. It is understood that the expander tool, e.g., expansion
cone, can be deployed in a position inverted from that shown in the
drawings. In such an arrangement, the expander tool 200 is
releasably attached to the sand screen 100 (or some tool below the
sand screen 100), and is then pulled upward through the sand screen
100 during the expansion process. The sand screen 100 would then be
expanded in compression against the hanger 140 as the expander tool
200 is pulled upwards. Alternatively, the expandable tubular 100
may be expanded in compression by resting the sand screen 100 on
and against a cement shoe 180 or "mule shoe." The mule shoe may be
drillable and would be part of the deployment equipment. No hanger
would be required because the cement shoe 180 would be resting on
the bottom of the borehole. In this alternate arrangement, the cone
200 would again be releasably attached to the top connector 110 (or
otherwise above the sand screen 100), or form part of an expansion
string.
[0063] It should also be noted that the steps in FIGS. 7B and 7C
may be reversed. In this respect, the cement 55 may be injected
into the annular region before the tubular 100 is expanded. The
expansion operation is then conducted before the cement 55 has
completely cured. Any cement deposited in the main bore of the sand
screen 100 (or other expandable tubular) is then drilled out.
[0064] FIG. 7D demonstrates the optional step of drilling cement 55
out of the main bore of the sand screen 100. The sand screen 100 in
its expanded state is shown in the view of FIG. 7D. The expander
tool 200' (and run-in tool) has been removed from the wellbore 40,
and the working string 70 has been reintroduced into the wellbore
40. A drill bit 75 is now seen at the lower end of the working
string 70. In the step of FIG. 7D, the drill bit is drilling out
cement 55 that is inside the sand screen 100. A thin cement sheath
55' is now left around the sand screen 100.
[0065] Next, FIG. 7E presents the wellbore of FIG. 7A having been
completed. The drill bit 75 has been removed from the wellbore 40,
and fluids are being produced through the cement column 55 and
through the sand screen 100. Arrows 15 depict the flow of fluids,
such as hydrocarbons, into the wellbore 40.
[0066] FIGS. 8A-8E present steps for deploying a sand screen in
accordance with another of the methods of the present invention. In
each of these drawings, a cross-sectional view of a wellbore 40 is
again seen. In this instance, the wellbore 40 is cased with a
string of casing, such as a liner string 30.
[0067] In FIG. 8A, a liner string 30 is shown within the wellbore
40. The liner string 30 has been perforated. FIG. 8A could
represent a new wellbore that is just being completed with new
perforations 35; alternatively, it could represent an old well
having perforated casing that has corroded and is in need of
support provided by a sand screen.
[0068] FIG. 8B demonstrates the sand screen 100 being run into the
wellbore 40 of FIG. 8A at the end of a working string 70. The sand
screen 100 is temporarily connected to the working string 70 via a
run-in tool (not shown). A packer 150 is positioned above the sand
screen 100. The sand screen 100 is releasably attached to an
expander tool 200', while the expander tool 200', in turn, is
attached to the lower end of the working string 70. The sand screen
100 is located at a depth that traverses the perforated zone of the
liner string 30. In the arrangement of FIG. 8B, the sand screen 100
is simply landed on the bottom of the open borehole 50. A mule shoe
180 is shown resting at the bottom of the hole.
[0069] FIG. 8C presents the next step in the completion process. In
FIG. 8C, the packer 150 has been set in the wellbore 40. A liner
hanger is not needed in this arrangement, as the sand screen 100 is
resting at the bottom of the hole. Axial stress has sheared the
shear pins (not shown), releasing the cone 200' from the top
connector (shown as 110 in FIG. 6A). This allows the cone 200' to
move downward relative to the expandable tubular 100. The cone 200'
is moved downward at the lower end of the working string 70. As the
cone 200' is urged downward, the expandable tubular 100 is radially
expanded along its length. The tubular 100 is not expanded into
complete frictional engagement with the surrounding formation 48,
but an annular region is preserved. In the arrangement of FIG. 8C,
a tapered cone is again being used as the expander tool 200'.
However, it is again understood that the methods of the present
invention are not limited to the manner in which expansion is
accomplished, or the type of expander tool used.
[0070] FIG. 8D presents the next step in the completion process.
Here, cement 55 is being injected through the working string 70,
through the expander tool 200', and out of the mule shoe 180. The
cement 55 is then squeezed up the annular region defined by the
sand screen 100 and the surrounding formation wall 48. In this way,
a thin tubular column of cement 55 is placed in the open hole
portion 50 of the wellbore 40.
[0071] It is noted in the arrangement of FIG. 8D that the working
string 70 and the expander tool 200' have been raised in the
wellbore 40. This allows cement 55 to also fill all or a portion of
the main bore of the expandable tubular 100. In this respect, it is
optional in the methods of the present invention to place cement 55
not only in the annular region outside of the sand screen 100, but
also within the sand screen 100 or other expandable tubular
itself.
[0072] The sand screen 100 of FIG. 8B is shown in its expanded
state in the view of FIG. 8E. Here, the sand screen 100 has been
expanded along a desired length. The expander tool 200 has been
removed from the wellbore 40, and the working string 70 has been
reintroduced into the wellbore 40. A drill bit 75 is now seen at
the lower end of the working string 70. In the step of FIG. 8E, the
drill bit is drilling out at least a portion of the cement 55 that
is inside the sand screen 100. A thin cement sheath 55' is now left
around the sand screen 100.
[0073] FIG. 8F presents the wellbore 40 of FIG. 8B having been
completed. The drill bit 75 is removed from the wellbore 40, and
fluids are being produced through the cement column 55' and through
the sand screen 100. Arrows 15 depict the flow of fluids, such as
hydrocarbons, into the wellbore 40.
[0074] In order for the methods shown in FIGS. 7A-7E, and FIGS.
8A-8F to work most effectively, it is desirable to provide cement
55 having characteristics of increased permeability. The cement
pore sizes should, after cure, be sized to prevent the formation
sand grains from passing through under pressure, while still
allowing the passage of fluids and clay (fines) particles. In this
manner, the cement 55 aids in the sand filtering process without
preventing the flow of valuable hydrocarbons into the wellbore 40.
An example is a hollow fiber cement, which provides small pore
passages incorporated within the structure of the cement. The
hollow fiber tubules also improve the structural integrity of the
cement sheath. Alternatively, a permeable cement such as that
described in U.S. Pat. Nos. 6,364,945 and 6,202,751, mentioned
earlier, may be employed. The '945 and the '751 patents are
incorporated herein by reference, in their respective
entireties.
[0075] When using a porous and permeable cement, the operator may
introduce an acid to create interconnecting vugs and channels in
the cement. This procedure is set out more fully in U.S. Pat. No.
6,390,195, mentioned earlier. The '195 patent is also incorporated
herein by reference, in its entirety. In one aspect, the cement is
comprised of a hydraulic cement, a particulate cross-linked gel
containing an internal breaker which after time causes said gel to
break into a liquid, and water present in an amount sufficient to
form a slurry. After the cement has been injected into the
wellbore, and after it has been drilled out of the sand screen, the
delayed internal breaker in the cement breaks. Acid is then
introduced into the wellbore and through the sand screen where it
comes into contact with the set cement. The acid dissolves portions
of the set cement composition connecting the channels therein such
that the set cement column 55' is permeated substantially along its
length and width. The well is then ready for production, as shown
in FIGS. 7E and 8F.
[0076] In one arrangement, the cement includes a particulate solid
that is soluble in the presence of a treating fluid, such as acid.
The acid dissolves the particulate solids, thereby creating vugs
and channels through which hydrocarbons flow. In another aspect,
the cement composition further comprises a gas present in an amount
sufficient to form a foam, and a mixture of foaming and foam
stabilizing surfactants.
[0077] Because the porous and permeable cement would introduce a
pressure drop into the completion, it is desirable that the
thickness of the cement sheath be minimized. The use of an
expandable tubular, such as an expandable sand screen or slotted
liner, allows the greatest possible inflow area into the wellbore
through the permeable cement, thereby minimizing cement thickness
and pressure drop. In addition, the use of an expandable tubular
allows wells to be under-reamed, thereby allowing significant
inflow advantages over conventional completion techniques.
Furthermore, since the tubular actually expands to an inside
diameter greater than the maximum outside diameter of the expander
tool, the final inside diameter of the tubular can be substantially
equal to that of the parent casing. This provides a larger
filtering surface area, resulting in a lower pressure drop than
using a conventional, non-expandable perforated pipe, and greater
longevity due to the number of pores available for flow. Further,
the use of an expandable tubular to support the cement sheath 55'
provides additional security in case of thermal or pressure related
stress cracking to the cement 55'. Wellbore support is provided
even in extreme wash-outs and reactive shales. Thus, the above
methods when used in cased and perforated wells are highly erosion
resistant as the sand grains are kept in place.
[0078] It should also be noted that the methods of the present
invention may be used with a combination of permeable and
non-permeable cement in a multi-stage cement job. In this respect,
a producing zone can be isolated by cementing the annulus above and
below the producing zone with a non-permeable cement. A permeable
cement can be squeezed into the area adjacent the producing zone.
The multi-stage cement job can be done in various steps--the order
is not important for purposes of the present inventions. By using
normal cement and permeable cement in a multi-stage cement job
coupled with the tubular mechanical support provided by the
expandable sand screen or tubular, a stable and effective sand
control method can be provided without gravel packing and
perforating operations.
[0079] While the foregoing is directed to embodiments of the
present invention, other and further embodiments of the invention
may be devised without departing from the basic scope thereof. For
example, a crossover port and a cement shoe can be added to the
deployment equipment. The sand screen or tubular would be expanded
after the cement is poured. The cement would then be pumped through
the expansion cone while it is on bottom and up through a preserved
annulus between the sand screen and the wall of the borehole. The
cement would not pass through the sand screen, so no drilling step
would be required. The deployment equipment is then retrieved,
leaving a clean production bore.
* * * * *