U.S. patent application number 12/853098 was filed with the patent office on 2012-02-09 for swellable elastomer for water shut off in gravel pack.
This patent application is currently assigned to Weatherford/Lamb, Inc.. Invention is credited to Jeffrey J. Lembcke.
Application Number | 20120031612 12/853098 |
Document ID | / |
Family ID | 44532688 |
Filed Date | 2012-02-09 |
United States Patent
Application |
20120031612 |
Kind Code |
A1 |
Lembcke; Jeffrey J. |
February 9, 2012 |
Swellable Elastomer for Water Shut Off in Gravel Pack
Abstract
An improved gravel pack material includes granules of a
swellable elastomer selected to trigger by a surrounding fluid.
When a fluid breakthrough occurs in a gravel-packed well, the
swellable elastomer granules swell in the presence of the fluid at
the point of the breakthrough, sealing off or reducing the flow of
the fluid through the breakthrough into the well.
Inventors: |
Lembcke; Jeffrey J.;
(Houston, TX) |
Assignee: |
Weatherford/Lamb, Inc.
Houston
TX
|
Family ID: |
44532688 |
Appl. No.: |
12/853098 |
Filed: |
August 9, 2010 |
Current U.S.
Class: |
166/278 ;
166/51 |
Current CPC
Class: |
E21B 43/04 20130101;
C09K 8/516 20130101 |
Class at
Publication: |
166/278 ;
166/51 |
International
Class: |
E21B 43/04 20060101
E21B043/04 |
Claims
1. An gravel pack material, comprising: a mixture comprising: a
first volume of gravel; and a second volume of granules of a
swellable elastomeric material, selected to expand on exposure to a
predetermined well fluid.
2. The gravel pack material of claim 1, wherein the predetermined
well fluid is water.
3. The gravel pack material of claim 1, wherein the predetermined
well fluid is a combination of hydrocarbons and water.
4. The gravel pack material of claim 1, wherein the gravel
comprises particles of a first average size; and wherein the
granules of the swellable elastomeric material are formed of a
second average size corresponding to the first average size.
5. The gravel pack material of claim 4, wherein the second average
size is less than the first average size.
6. The gravel pack material of claim 1, wherein the second volume
of granules of the swellable elastomeric material is at least 25%
of the first volume of gravel.
7. The gravel pack material of claim 1, wherein the granules of the
swellable elastomeric material are formed with irregular
shapes.
8. A material, comprising: granules formed of a swellable
elastomeric material, selected to expand on exposure to a
predetermined well fluid, wherein the granules are sized for
mixture with a gravel.
9. The material of claim 8, wherein the gravel is formed of
particles of a predetermined average size, and wherein the granules
are formed of an average size selected based on the average size of
the particles of gravel.
10. The material of claim 8, wherein the predetermined well fluid
is water.
11. The material of claim 8, wherein the predetermined well fluid
is a combination of hydrocarbons and water.
12. The material of claim 8, wherein the predetermined well fluid
is a hydrocarbon.
13. A method of gravel packing a well; comprising: positioning a
tubular in a wellbore, forming an annulus between the tubular and a
surrounding surface; and depositing a gravel pack formed of a
mixture of gravel particles and granules of a swellable elastomeric
material in the annulus, wherein the swellable elastomer is
selected to expand on exposure to a predetermined well fluid.
14. The method of claim 13, further comprising: mixing the gravel
and the granules of the swellable elastomeric material at the
well.
15. The method of claim 13, wherein the predetermined well fluid is
water.
16. The method of claim 13, wherein the predetermined well fluid is
a hydrocarbon.
17. The method of claim 13, further comprising: forming the
granules of the swellable elastomeric material to have an average
size less than an average size of the gravel particles.
18. The method of claim 13, further comprising: forming the
granules of the swellable elastomeric material to have an average
size corresponding to an average size of the gravel particles.
19. The method of gravel packing a well, further comprising: mixing
a first volume of the gravel particles with a second volume of the
granules of swellable elastomeric material to form the gravel pack,
wherein the second volume is at least 25% of the first volume.
20. The method of gravel packing a well, further comprising:
forming the granules of the swellable elastomeric material to have
an irregular shape.
Description
TECHNICAL FIELD
[0001] The present invention relates to the field of downhole
tools, and in particular to gravel pack completions.
BACKGROUND ART
[0002] Gravel packing is a method of well completion in which a
slotted or perforated liner is placed in a well and surrounded with
a gravel mixture. Gravel packing is most commonly used in the open
hole wells, but may also be used in cased wells. The mass of gravel
in the gravel pack excludes sand from the wellbore, while allowing
continued production.
SUMMARY OF INVENTION
[0003] By mixing granules of swellable elastomer into the gravel
pack, fluid breakthroughs can be restricted or eliminated in a
self-actuated self-healing gravel pack completion.
BRIEF DESCRIPTION OF DRAWINGS
[0004] The accompanying drawings, which are incorporated in and
constitute a part of this specification, illustrate an
implementation of apparatus and methods consistent with the present
invention and, together with the detailed description, serve to
explain advantages and principles consistent with the invention. In
the drawings,
[0005] FIG. 1 is a cutaway view illustrating a gravel pack
completion according to the prior art with a fluid
breakthrough.
[0006] FIG. 2 is a cutaway view illustrating a gravel pack
completion according to one embodiment.
[0007] FIG. 3 is a cutaway view illustrating a self-actuated
closure of a fluid breakthrough achieved by the embodiment of FIG.
2.
DESCRIPTION OF EMBODIMENTS
[0008] In the following description, for purposes of explanation,
numerous specific details are set forth in order to provide a
thorough understanding of the invention. It will be apparent,
however, to one skilled in the art that the invention may be
practiced without these specific details. In other instances,
structure and devices are shown in block diagram form in order to
avoid obscuring the invention. References to numbers without
subscripts or suffixes are understood to reference all instance of
subscripts and suffixes corresponding to the referenced number.
Moreover, the language used in this disclosure has been principally
selected for readability and instructional purposes, and may not
have been selected to delineate or circumscribe the inventive
subject matter, resort to the claims being necessary to determine
such inventive subject matter. Reference in the specification to
"one embodiment" or to "an embodiment" means that a particular
feature, structure, or characteristic described in connection with
the embodiments is included in at least one embodiment of the
invention, and multiple references to "one embodiment" or "an
embodiment" should not be understood as necessarily all referring
to the same embodiment.
[0009] One problem with gravel pack completions has been fluid
breakthroughs from the surrounding strata. FIG. 1 is a cutaway view
of a typical gravel-packed completion according to the prior art. A
tubular 130 is inserted into the open hole well, with slots 135
allowing fluid passage in the annulus between the tubular 130 and
the open hole rock or sands 100. A gravel pack 120 is inserted in
the annulus between the tubular 130 and the open hole.
[0010] When a crack or fissure 140 occurs in the surrounding open
hole 100, water or other fluids may leak into the annulus, flowing
through the gravel pack 120 an end to the poor of the tubular 130
through slots 135, as illustrated in area 145 in FIG. 1. Such a
fluid breakthrough can be difficult to shut off. In conventional
gravel pack completions, packers between zones and the water shut
off sleeves that require intervention to close have been used to
shut off fluid breakthroughs.
[0011] FIG. 2 illustrates an improved gravel pack completion
technique using a gravel pack 200 according to one embodiment that
may eliminate or reduce the problem illustrated in FIG. 1. In
addition to conventional gravel, the improved gravel pack 200
includes a predetermined amount of a swellable elastomer performed
as granules that are mixed into the gravel pack. During normal
operation after the gravel packing, the improved gravel pack 200
operates just as the conventional gravel pack 120, with the gravel
and elastomer mixture excluding sand from traversing the slots 135
and entering the bore of the tubular 130.
[0012] As illustrated in FIG. 3, however, when a water or other
fluid breakthrough occurs through fissure 140, the swellable
elastomer granules in area 300 swellable in the presence of a fluid
and at least partially restrict or shuts off the flow of fluid into
the tubular. This creates an autonomous self-actuated fluid shut
off in the improved gravel pack 200 itself
[0013] Only the area 300 of the gravel pack 200 that is in contact
with the triggering fluid actuates, thus other portions of the
gravel pack 200 may continue to function normally. Because
swellable material such as are selected for the improved gravel
pack 200 remain swollen once they have been exposed to their
triggering fluid, the shut off is long lasting and may indeed be
permanent.
[0014] Many gravel pack wells are in areas where the open hole
breakthrough would be a water breakthrough, thus in one embodiment,
the swellable elastomer granules are formed of a material selected
to swell when exposed to water, such as a nitrile, or a nitrile
mixed with a super absorbent polymer. In other embodiments, where
the fluid may be a hydrocarbon fluid, or a mixture of water and
hydrocarbons, the elastomer granules may be formed of an ethylene
propylene diene monomer (EPDM) or a mixture of nitrile and EPDM
granules.
[0015] The granules may be formed as irregular chunks of the
swellable elastomer, or in any desired 3-dimensional configuration.
The granules may be sized in multiple sizes, and in one embodiment
may be sized to correspond to the average particle size of the
gravel in the gravel pack 200. In other embodiments, the swellable
elastomer particles are sized to be smaller than the average gravel
particle size.
[0016] The swellable elastomer is preferably evenly mixed with the
gravel. In one embodiment, the gravel-elastomer mixture may be
mixed on-site. In other embodiments, the gravel and elastomer
particles may be premixed off-site.
[0017] The desired relative percentage of gravel to elastomer
particles may vary for different applications, but in most
embodiments, the elastomeric granules may comprise at least 25% by
volume of the gravel-elastomer mixture.
[0018] It is to be understood that the above description is
intended to be illustrative, and not restrictive. For example, the
above-described embodiments may be used in combination with each
other. Many other embodiments will be apparent to those of skill in
the art upon reviewing the above description. The scope of the
invention therefore should be determined with reference to the
appended claims, along with the full scope of equivalents to which
such claims are entitled. In the appended claims, the terms
"including" and "in which" are used as the plain-English
equivalents of the respective terms "comprising" and "wherein."
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