U.S. patent application number 12/152327 was filed with the patent office on 2009-11-19 for extended cement compositions comprising oil-swellable particles and associated methods.
Invention is credited to D. Chad Brenneis, Jiten Chatterji, Bobby J. King, Craig W. Roddy.
Application Number | 20090283269 12/152327 |
Document ID | / |
Family ID | 40810430 |
Filed Date | 2009-11-19 |
United States Patent
Application |
20090283269 |
Kind Code |
A1 |
Roddy; Craig W. ; et
al. |
November 19, 2009 |
Extended cement compositions comprising oil-swellable particles and
associated methods
Abstract
A variety of methods and compositions are disclosed herein,
including, in one embodiment, a method of cementing in a
subterranean formation comprising: providing an extended cement
composition comprising cement, water, an oil-swellable particle,
and a set retarding additive, wherein the extended cement
composition is capable of remaining in a pumpable fluid state for
at least about 1 day; adding a cement set accelerator to the
extended cement composition; introducing the extended cement
composition into a well bore; and allowing the extended cement
composition to set. Another embodiment comprises an extended cement
composition comprising: cement; water; an oil-swellable particle;
and a set retarding additive, wherein the extended cement
composition is capable of remaining in a pumpable fluid state for
at least about 1 day.
Inventors: |
Roddy; Craig W.; (Duncan,
OK) ; Chatterji; Jiten; (Duncan, OK) ;
Brenneis; D. Chad; (Marlow, OK) ; King; Bobby J.;
(Duncan, OK) |
Correspondence
Address: |
CRAIG W. RODDY;HALLIBURTON ENERGY SERVICES
P.O. BOX 1431
DUNCAN
OK
73536-0440
US
|
Family ID: |
40810430 |
Appl. No.: |
12/152327 |
Filed: |
May 14, 2008 |
Current U.S.
Class: |
166/293 ;
106/638 |
Current CPC
Class: |
C04B 28/02 20130101;
C04B 28/02 20130101; C04B 2103/22 20130101; C04B 2111/00146
20130101; C09K 8/467 20130101; C04B 24/2676 20130101; C04B 2103/12
20130101; C04B 24/2611 20130101 |
Class at
Publication: |
166/293 ;
106/638 |
International
Class: |
C09K 8/467 20060101
C09K008/467; C04B 28/00 20060101 C04B028/00 |
Claims
1. A method of cementing in a subterranean formation comprising:
providing an extended cement composition consisting essentially of:
cement, water, an oil-swellable particle, and a set retarding
additive, wherein the extended cement composition is unfoamed and
capable of remaining at a viscosity of less than 70 Bc at room
temperature for at least about 1 day; storing the extended cement
composition for a period of time; adding a cement set accelerator
to the extended cement composition; introducing the extended cement
composition into the subterranean formation; allowing the extended
cement composition to set in the subterranean formation; and
allowing the oil-swellable particle in the set cement composition
to contact oil whereby the oil-swellable particle swells to
counteract either a crack that forms in the set cement composition
or a micro-annulus between the set cement composition and either a
pipe string or the subterranean formation.
2. The method of claim 1 wherein the extended cement composition is
capable of remaining in a pumpable fluid state for at least about 5
days.
3. The method of claim 1 wherein the extended cement composition
sets to have a 72-hour compressive strength at 140.degree. F. of at
least about 100 psi.
4. The method of claim 1 wherein the extended cement composition is
introduced into a space between the subterranean formation
surrounding the well bore and a pipe string disposed in the well
bore.
5. The method of claim 4 comprising introducing the pipe string
into the well bore.
6. The method of claim 1 wherein the cement comprises a hydraulic
cement.
7. The method of claim 1 wherein the oil-swellable particle
comprises an oil-swellable elastomer.
8. The method of claim 1 wherein the oil-swellable particle
comprises a block copolymer of styrene butadiene.
9. The method of claim 1 wherein the oil-swellable particle is
present in an amount of about 1% to about 25% bwoc and the
oil-swellable particle comprises a block copolymer of styrene
butadiene.
10. The method of claim 1 wherein the oil-swellable particle is
present in the extended cement composition in an amount up to about
27% by weight of the cement.
11. The method of claim 1 wherein the set retarding additive
comprises at least one additive selected from the group consisting
of an organic acid, a lignosulfonate, and a synthetic retarder.
12. The method of claim 1 wherein the cement set accelerator
comprises at least one additive selected from the group consisting
of calcium chloride, triethanolamine, sodium silicate, zinc
formate, and calcium acetate.
13. A method of cementing in a subterranean formation comprising:
providing an extended cement composition consisting essentially of:
hydraulic cement, water, an oil-swellable particle, a set retarding
additive, and an additional additive comprising at least one
additive selected from the group consisting of a weight reducing
additive, a heavyweight additive, a lost circulation material, a
filtration control additive, a dispersant, a suspending agent, a
crystalline silica compound, amorphous silica, salt, fiber, a
hydratable clay, a microsphere, a pozzolan additive, latex cement,
a thixotropic additive, and combinations thereof, wherein the
extended cement composition is unfoamed and capable of remaining at
a viscosity of less than 70 Bc at room temperature for at least
about 1 day; storing the extended cement composition for a period
of time; adding a cement set accelerator to the extended cement
composition; introducing the extended cement composition into the
subterranean formation; allowing the extended cement composition to
set in the subterranean formation; and allowing the oil-swellable
particle in the set cement composition to contact oil whereby the
oil-swellable particle swells to counteract either a crack that
forms in the set cement composition or a micro-annulus between the
set cement composition and either a pipe string or the subterranean
formation.
14. The method of claim 13 wherein the extended cement composition
sets to have a 72-hour compressive strength of at least about 100
psi in the well bore.
15. The method of claim 13 wherein the extended cement composition
is introduced into a space between the subterranean formation
surrounding the well bore and a pipe string disposed in the well
bore.
16. The method of claim 13 wherein the oil-swellable particle
comprises an oil-swellable elastomer.
17. The method of claim 13 wherein the oil-swellable particle
comprises a block copolymer of styrene butadiene.
18. The method of claim 13 wherein the oil-swellable particle is
present in an amount of about 1% to about 25% bwoc and the
oil-swellable particle comprises a block copolymer of styrene
butadiene.
19. The method of claim 13 wherein the oil-swellable particle is
present in the extended cement composition in an amount up to about
27% by weight of the hydraulic cement.
20. (canceled)
21. A method of cementing in a subterranean formation comprising:
providing an extended cement composition comprising: cement, water,
an oil-swellable particle that comprises a block copolymer of
styrene butadiene, and a set retarding additive comprising at least
one additive selected from the group consisting of an organic acid,
a lignosulfonate, and a synthetic retarder, wherein the extended
cement composition is unfoamed and capable of remaining at a
viscosity of less than 70 Bc at room temperature for at least about
1 day, storing the extended cement composition for a period of
time; adding a cement set accelerator to the extended cement
composition, wherein the cement set accelerator comprises at least
one additive selected from the group consisting of calcium
chloride, triethanolamine, sodium silicate, zinc formate, and
calcium acetate; introducing the extended cement composition into
an annulus between a pipe string and the subterranean formation;
and allowing the extended cement composition to set in the
annulus.
22. The method of claim 21 comprising: allowing the oil-swellable
particle in the set cement composition to contact oil whereby the
oil-swellable particle swells to counteract either a crack that
forms in the set cement or a micro-annulus between the set cement
composition and either the pipe string or the subterranean
formation.
23. The method of claim 1 wherein the oil-swellable particle
comprises at least one elastomer selected from the group consisting
of natural rubber, acrylate butadiene rubber, polyacrylate rubber,
isoprene rubber, choloroprene rubber, butyl rubber, brominated
butyl rubber, chlorinated butyl rubber, chlorinated polyethylene,
neoprene rubber, styrene butadiene copolymer rubber, styrene
butadiene block copolymer rubber, sulphonated polyethylene,
ethylene acrylate rubber, epichlorohydrin ethylene oxide copolymer,
ethylene-propylene rubber, ethylene-propylene diene terpolymer
rubber, ethylene vinyl acetate copolymer, fluorosilicone rubber,
silicone rubber, poly 2,2,1-bicyclo heptene (polynorborneane),
alkylstyrene, crosslinked substituted vinyl acrylate copolymer, and
combinations thereof.
24. The method of claim 13 wherein the oil-swellable particle
comprises at least one elastomer selected from the group consisting
of natural rubber, acrylate butadiene rubber, polyacrylate rubber,
isoprene rubber, choloroprene rubber, butyl rubber, brominated
butyl rubber, chlorinated butyl rubber, chlorinated polyethylene,
neoprene rubber, styrene butadiene copolymer rubber, styrene
butadiene block copolymer rubber, sulphonated polyethylene,
ethylene acrylate rubber, epichlorohydrin ethylene oxide copolymer,
ethylene-propylene rubber, ethylene-propylene diene terpolymer
rubber, ethylene vinyl acetate copolymer, fluorosilicone rubber,
silicone rubber, poly 2,2,1-bicyclo heptene (polynorborneane),
alkylstyrene, crosslinked substituted vinyl acrylate copolymer, and
combinations thereof.
25. The method of claim 1 wherein the extended cement composition
remains pumpable for at least about one day.
26. The method of claim 1 wherein the extended cement composition
remains pumpable for at least about 5 days.
27. The method of claim 13 wherein the extended cement composition
remains pumpable for at least about one day.
28. The method of claim 13 wherein extended cement composition
remains pumpable for at least about 5 days.
29. The method of claim 21 wherein the extended cement composition
remains pumpable for at least about 5 days.
Description
BACKGROUND
[0001] The present invention relates to cementing operations and,
more particularly, to extended cement compositions comprising
cement, water, oil-swellable particles, and a set retarding
additive and associated methods of use.
[0002] Cement compositions are commonly utilized in subterranean
operations, particularly subterranean well construction and
remedial operations. For example, in subterranean well
construction, a pipe string (e.g., casing, liners, etc.) may be
introduced into the well and cemented in place. The process of
cementing the pipe string in place is commonly referred to as
"primary cementing." In a typical primary cementing operation, a
cement composition may be pumped into an annulus between the walls
of a well bore and the exterior surface of the pipe string disposed
therein. The cement composition sets in the annular space, thereby
forming an annular sheath of hardened, substantially impermeable
cement that supports and positions the pipe string in the well bore
and bonds the exterior surface of the pipe string to the walls of
the well bore. Among other things, the annular sheath of set cement
surrounding the pipe string functions to prevent the migration of
fluids in the annulus, as well as protecting the pipe string from
corrosion. Cement compositions also may be used in remedial
cementing operations, such as squeeze cementing and the placement
of cement plugs.
[0003] Once set, the cement sheath may be subjected to a variety of
cyclic, shear, tensile, impact, flexural, and/or compressive
stresses that may lead to failure of the cement sheath. Such
failure may be the result of fractures, cracks, and/or debonding of
the cement sheath from the pipe string and/or the formation.
Undesirably, cement-sheath failure may lead to loss of zonal
isolation, resulting, for example, in the undesirable migration of
fluids between formation zones. This may lead to undesirable
consequences such as lost production, costly remedial operations,
environmental pollution, hazardous rig operations resulting from
unexpected fluid flow from the formation caused by the loss of
zonal isolation, and/or hazardous production operations.
Furthermore, failure of the cement sheath also may be caused by
forces exerted by shifts in subterranean formations surrounding the
well bore, cement erosion, and repeated impacts from the drill bit
and the drill pipe.
[0004] In certain applications, extended cement compositions may be
used. As used herein, the term "extended cement composition" refers
to a cement composition capable of remaining in a pumpable fluid
state for an extended period of time (e.g., at least about 1 day).
A fluid is considered to be in a pumpable fluid state where the
fluid has a viscosity of less than 70 Bc, as measured using an FANN
Atmospheric Consistometer Model 165AT (available from FANN
Instrument Company, Houston, Tex.) at room temperature (for
example, 78.degree. F.). In general, the extended cement
compositions comprise cement, water, and a set retarder and remain
in a pumpable fluid state for an extended period of time. When
desired for use, the extended cement composition should be capable
of being activated whereby reasonable compressive strengths are
developed. For example, a cement set accelerator may be added to
the extended cement composition whereby the composition sets into a
hardened mass. Among other things, the extended cement compositions
may be suitable for use in well bore applications, for example,
where it is desired to prepare the cement composition in advance.
This may allow, for example, the cement composition to be stored
prior to its use. In addition, this may allow, for example, the
cement composition to be prepared at a convenient location and then
transported to the job site for use. Accordingly, capital
expenditures associated with the cementing operations may be
reduced due to a reduction in the need for on-site bulk storage and
mixing equipment.
SUMMARY
[0005] The present invention relates to cementing operations and,
more particularly, to extended cement compositions comprising
cement, water, oil-swellable particles, and a set retarding
additive and associated methods of use.
[0006] One embodiment of the present invention comprises a method
of cementing in a subterranean formation comprising: providing an
extended cement composition comprising cement, water, an
oil-swellable particle, and a set retarding additive, wherein the
extended cement composition is capable of remaining in a pumpable
fluid state for at least about 1 day; adding a cement set
accelerator to the extended cement composition; introducing the
extended cement composition into a well bore; and allowing the
extended cement composition to set.
[0007] Another embodiment of the present invention comprises a
method of cementing in a subterranean formation comprising:
providing an extended cement composition comprising hydraulic
cement, water, an oil-swellable particle, and a set retarding
additive; storing the extended cement composition; adding a cement
set accelerator to the extended cement composition; introducing the
extended cement composition into a well bore; and allowing the
extended cement composition to set.
[0008] Another embodiment of the present invention comprises an
extended cement composition comprising: cement; water; an
oil-swellable particle; and a set retarding additive, wherein the
extended cement composition is capable of remaining in a pumpable
fluid state for at least about 1 day.
[0009] The features and advantages of the present invention will be
apparent to those skilled in the art. While numerous changes may be
made by those skilled in the art, such changes are within the
spirit of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] These drawings illustrate certain aspects of some of the
embodiments of the present invention, and should not be used to
limit or define the invention.
[0011] FIG. 1 is a photograph comparing the expansion of a cement
cube comprising oil-swellable particles after 4 days immersion in
an oil bath, in accordance with one embodiment of the present
invention.
[0012] FIG. 2 is a photograph illustrating the swelling of
oil-swellable particles included in a cement cube after immersion
of the cube in an oil bath, in accordance with one embodiment of
the present invention.
[0013] FIG. 3 is another photograph illustrating the swelling of
oil-swellable particles included in a cement cube after immersion
of the cube in an oil bath, in accordance with one embodiment of
the present invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0014] The present invention relates to cementing operations and,
more particularly, to extended cement compositions comprising
cement, water, oil-swellable particles, and a set retarding
additive and associated methods of use.
[0015] In certain embodiments, the present invention provides
extended cement compositions that are capable of remaining in a
pumpable fluid state for an extended period of time. For example,
the extended cement compositions may be capable of remaining in a
pumpable fluid state for at least about 1 day or longer (e.g., at
least about 1 day, 2 days, 3 days, 4 days, 5 days, or the like).
When desired for use, the extended cement composition may be
activated (e.g., by addition of a cement set accelerator) to
thereby set into a hardened mass. By way of example, the extended
cement composition, after activation, may set to a compressive
strength (as determined using the procedure set forth in API
Specification 10) at 140.degree. F. of at least about 100 psi in 72
hours, alternatively at least about 500 psi. Among other things,
the extended cement compositions of the present invention may be
suitable for use in well bore applications, for example, where it
is desired to prepare the cement composition in advance. By way of
example, the extended cement compositions may facilitate
preparation of the cement composition at a convenient location and
then transport to the job site for use in the cementing
operation.
[0016] An example of a suitable extended cement composition of the
present invention comprises cement, water, an oil-swellable
particle, and a set retarding additive. Optionally, a suspending
agent may be included in the extended cement composition as
desired. The extended cement compositions of the present invention
should have a density suitable for a particular application as
desired by those of ordinary skill in the art, with the benefit of
this disclosure. In some embodiments, the extended cement
compositions of the present invention may have a density in the
range of about 8 pounds per gallon ("lb/gal") to about 16
lb/gal.
[0017] Embodiments of the extended cement compositions of the
present invention generally comprise a cement. In certain
embodiments, the cement comprises hydraulic cement. A variety of
hydraulic cements may be utilized in accordance with embodiments of
the present invention, including, but not limited to, those
comprising calcium, aluminum, silicon, oxygen, iron, and/or sulfur,
which set and harden by reaction with water. Suitable hydraulic
cements include, but are not limited to, Portland cements,
pozzolana cements, gypsum cements, high alumina content cements,
slag cements, silica cements, and combinations thereof. In certain
embodiments, the hydraulic cement may comprise a Portland cement.
In some embodiments, the Portland cements that are suited for use
in the present invention are classified as Classes A, C, H, and G
cements according to American Petroleum Institute, API
Specification for Materials and Testing for Well Cements, API
Specification 10, Fifth Ed., Jul. 1, 1990.
[0018] The water used in embodiments of the extended cement
compositions of the present invention may include, for example,
freshwater, saltwater (e.g., water containing one or more salts
dissolved therein), brine (e.g., saturated saltwater produced from
subterranean formations), seawater, or combinations thereof.
Generally, the water may be from any source, provided that it does
not contain an excess of compounds that may undesirably affect
other components in the settable composition. In some embodiments,
the water may be included in an amount sufficient to form a
pumpable slurry. In some embodiments, the water may be included in
the extended cement compositions of the present invention in an
amount in the range of about 40% to about 200% by weight of the
cement ("bwoc") (e.g., about 50%, about 60%, about 70%, about 80%,
about 90%, about 100%, about 110%, about 120%, about 130%, about
140%, about 150%, about 160%, about 170%, about 180%, about 190%,
etc.). In some embodiments, the water may be included in an amount
in the range of about 40% to about 150% bwoc.
[0019] As set forth above, embodiments of the extended cement
compositions may comprise an oil-swellable particle. As used
herein, a particle is characterized as oil swellable when it swells
upon contact with oil. In accordance with embodiments of the
present invention, the oil-swellable particle may be included in
the extended cement composition, for example, to counteract the
formation of cracks in the cement sheath and/or micro-annulus
between the cement sheath and the pipe string or the formation. In
general, the oil-swellable particle should be capable of swelling
when contacted by oil to inhibit fluid flow through the crack
and/or micro-annulus. Accordingly, the oil-swellable particle may
prevent and/or reduce the loss of zonal isolation in spite of the
formation of cracks and/or micro-annulus, potentially resulting in
an improved annular seal for the extended cement compositions.
[0020] An example of an oil-swellable particle that may be utilized
in embodiments of the present invention comprises an oil-swellable
elastomer. Oil-swellable elastomers suitable for use in embodiments
of the present invention may generally swell by up to about 500% of
their original size at the surface when contacted by oil. Under
downhole conditions, this swelling may be more, or less, depending
on the conditions presented. For example, the swelling may be at
least 10% at downhole conditions. In some embodiments, the swelling
may be up to about 200% under downhole conditions. However, as
those of ordinary skill in the art, with the benefit of this
disclosure, will appreciate, the actual swelling when the swellable
elastomer is included in a cement composition may depend on, for
example, the concentration of the swellable elastomer included in
the cement composition, downhole pressure, and downhole
temperature, among other factors. Some specific examples of
suitable swellable elastomers include, but are not limited to,
natural rubber, acrylate butadiene rubber, polyacrylate rubber,
isoprene rubber, choloroprene rubber, butyl rubber (IIR),
brominated butyl rubber (BIIR), chlorinated butyl rubber (CIIR),
chlorinated polyethylene (CM/CPE), neoprene rubber (CR), styrene
butadiene copolymer rubber (SBR), styrene butadiene block copolymer
rubber, sulphonated polyethylene (CSM), ethylene acrylate rubber
(EAM/AEM), epichlorohydrin ethylene oxide copolymer (CO, ECO),
ethylene-propylene rubber (EPM and EDPM), ethylene-propylene-diene
terpolymer rubber (EPT), ethylene vinyl acetate copolymer,
fluorosilicone rubbers (FVMQ), silicone rubbers (VMQ), poly
2,2,1-bicyclo heptene (polynorborneane), alkylstyrene, and
crosslinked substituted vinyl acrylate copolymers. Combinations of
suitable oil-swellable elastomers may also be utilized. One example
of a suitable swellable elastomer comprises a block copolymer of a
styrene butadiene rubber. Other swellable elastomers that behave in
a similar fashion with respect to oil also may be suitable. Those
of ordinary skill in the art, with the benefit of this disclosure,
will be able to select an appropriate swellable elastomer for use
in the compositions of the present invention based on a variety of
factors, including the application in which the composition will be
used and the desired swellable characteristics.
[0021] Where used, the oil-swellable particle generally may be
included in the cement compositions in an amount sufficient to
provide the desired mechanical properties. In some embodiments, the
swellable particle may be present in the cement compositions in an
amount up to about 27% bwoc (e.g., about 1%, about 5%, about 10%,
about 15%, about 20%, about 25%, etc.), alternatively in a range of
about 1% to about 25% bwoc, and alternatively in a range of about
4% to about 20% bwoc.
[0022] In addition, the swellable particle that is utilized may
have a wide variety of shapes and sizes of individual particles
suitable for use in accordance with embodiments of the present
invention. By way of example, the swellable particle may have a
well-defined physical shape as well as an irregular geometry,
including the physical shape of platelets, shavings, fibers,
flakes, ribbons, rods, strips, spheroids, beads, toroids, pellets,
tablets, or any other physical shape. In some embodiments, the
swellable particle may have a particle size in the range of about 5
microns to about 1,500 microns. In some embodiments, the swellable
particle may have a particle size in the range of about 20 microns
to about 500 microns. However, particle sizes outside these defined
ranges also may be suitable for particular applications.
[0023] Embodiments of the extended cement compositions of the
present invention generally comprise a set retarding additive.
Examples of suitable set retarding additives include, but are not
limited to, organic acids, lignosulfonates, synthetic retarders and
combinations thereof. Examples of organic acids that may be
included in the extended cement compositions of the present
invention include, but are not limited to, tartaric acid, gluconic
acid, carboxylic acids (e.g., citric acid), hydroxy carboxy acids,
and combinations thereof. One example of a suitable set retarding
additive is tartaric acid, available from Halliburton Energy
Services under the trade name HR.RTM.-25 cement retarder. Examples
of lignosulfonates that may be included in the extended cement
compositions of the present invention include, but are not limited
to, a sulfomethylated lignin, calcium lignosulfonates, sodium
lignosulfonates, and combinations thereof. Examples of suitable
lignosulfonates include HR.RTM.-4, HR.RTM.-5, and HR.RTM.-7 cement
retarders available from Halliburton Energy Services, Inc. Examples
of synthetic retarders that may be included in the extended cement
compositions of the present invention include, but are not limited
to, copolymers of acrylic acid and 2-acrylamido-2-methyl-propane
sulfonic acid (or salts thereof) polymer and copolymers of maleic
anhydride and 2-acrylamido-2-methyl-propane sulfonic acid (or salts
thereof) polymer. Examples of suitable synthetic retarders include
SCR.TM.-100 and SCR.TM.-500 cement retarders available from
Halliburton Energy Services, Inc. Examples of suitable synthetic
retarders are described in U.S. Pat. Nos. 4,941,536, 5,049,288,
5,472,051, and 5,536,311, the disclosures of which are incorporated
herein by reference.
[0024] The set retarding additive should be included in the
extended cement compositions of the present invention in an amount
sufficient for the settable composition to remain in a pumpable
fluid state for an extended period of time (e.g., at least about 1
day). In certain embodiments, the set retarding additive may be
included in the extended cement composition in an amount in the
range of about 0.1% to about 5% bwoc (e.g., about 0.5%, about 1%,
about 2%, about 3%, about 4%, etc.). In certain embodiments, the
set retarding additive may be included in the extended cement
composition in an amount in the range of about 0.1% to about 1.5%
bwoc. Those of ordinary skill in the art, with the benefit of this
disclosure, should be able to determine an appropriate set
retarding additive and amount thereof for a particular
application.
[0025] As previously mentioned, at a desired time for use, the
extended cement composition may be activated, for example, by
addition of a cement set accelerator. Examples of suitable cement
set accelerators include, but are not limited to, calcium chloride,
triethanolamine, sodium silicate, zinc formate, calcium acetate,
and combinations thereof. An example of a suitable sodium silicate
is ECONOLITE.TM. additive, available from Halliburton Energy
Services, Inc. The cement set accelerator should be added to the
extended cement composition in an amount sufficient to activate the
extended cement composition to set into a hardened mass. In certain
embodiments, the cement set accelerator may be added to the
extended cement composition in an amount in the range of about 0.1%
to about 4% by weight (e.g., about 0.5%, about 1%, about 2%, about
3%, etc.).
[0026] Other additional additives also may be added to the extended
cement compositions of the present invention as deemed appropriate
by one skilled in the art, with the benefit of this disclosure.
Examples of such additives include, but are not limited to, weight
reducing additives, heavyweight additives, lost circulation
materials, filtration control additives, dispersants, suspending
agents, and combinations thereof. Suitable examples of these
additives include crystalline silica compounds, amorphous silica,
salts, fibers, hydratable clays, microspheres, pozzolan additives,
latex cement, thixotropic additives, combinations thereof and the
like.
[0027] The extended cement compositions of the present invention
may be used in a variety of subterranean applications, including,
but not limited to, primary and remedial cementing. An example of a
method of the present invention may comprise providing an extended
cement composition comprising cement, water, a swellable particle,
and a set retarding additive, wherein the extended cement
composition is capable of remaining in a pumpable fluid state for
at least about 1 day. The method further may comprise adding a
cement accelerator to the extended cement composition. And the
method further may comprise introducing the extended cement
composition into a well bore, and allowing the extended cement
composition to set.
[0028] Another example of a method of the present invention may
comprise providing an extended cement composition comprising
cement, water, a swellable particle, and a set retarding additive.
The method further may comprise storing the extended cement
composition. The method further may comprise adding a cement set
accelerator to the extended cement composition. And the method
further may comprise introducing the extended cement composition
into a well bore, and allowing the extended cement composition to
set.
[0029] Another example of a method of the present invention is a
method of cementing a pipe string (e.g., casing, expandable casing,
liners, etc.) disposed in a well bore. The method may comprise
providing an extended cement composition comprising cement, water,
a swellable particle, and a set retarding additive, wherein the
extended cement composition is capable of remaining in a pumpable
fluid state for at least about 1 day. The method further may
comprise adding a cement accelerator to the extended cement
composition. And the method further may comprise introducing the
extended cement composition into an annulus between the pipe string
and the subterranean formation surrounding the well bore, and
allowing the extended cement composition to set. In certain
embodiments, the method further may comprise introducing the pipe
string into the well bore.
[0030] To facilitate a better understanding of the present
invention, the following examples of certain aspects of some
embodiments are given. In no way should the following examples be
read to limit, or define, the scope of the invention.
EXAMPLE 1
[0031] To test the capability of a cement composition comprising
oil-swellable particles to remain in a pumpable liquid state for an
extended period of time, a sample extended cement composition was
prepared. The sample composition had a density of 14 lb/gal and
comprised Class H Texas Lehigh cement, water in an amount of 52.4%
bwoc, block copolymer of styrene-butadiene elastomeric particles in
an amount of 20% bwoc, and HR.RTM.5 cement retarder in an amount of
1% bwoc.
[0032] After preparation, the sample extended cement composition
was placed in a sealed plastic container at room temperature (e.g.,
about 78.degree. F.). The sample composition was observed on a
daily basis for flowability over 10 days. Observing the composition
for flowability involved shaking the plastic container and
observing whether the composition was flowable. For purposes of
this example, the composition was considered to be in a fluid state
based on visual observations, wherein the fluid was flowable when
the plastic container was shaken. After 10 days, the sample
extended cement composition remained flowable.
[0033] To determine the capability of this sample extended cement
composition to thereafter set into a hardened mass, calcium
chloride in an amount of 4% bwoc was added to the sample extended
cement composition. The thickening time of the sample composition
was then determined, in accordance with the above-referenced API
Specification 10. After addition of the calcium slurry, the sample
composition reached 70 Bc after 6 hours.
EXAMPLE 2
[0034] This example was performed to determine the capability of
the swellable particles in the sample extended cement composition
of Example 1 to swell when contacted by oil. Accordingly, a sample
extended cement composition was prepared that had a density of 14
lb/gal and comprised Class H Texas Lehigh cement, water in an
amount of 52.4% bwoc, block copolymer of styrene-butadiene
elastomeric particles in an amount of 20% bwoc, HR.RTM. 5 cement
retarder in an amount of 1% bwoc, and calcium chloride in an amount
of 4% bwoc.
[0035] The sample extended cement composition was formed into 3
cubes and cured at 140.degree. F. After 24 hours, the set cubes
were weighed. The cubes were then immersed in a mineral oil bath at
180.degree. F. Every 24 hours after immersion in the mineral oil
bath, the set cubes were removed from the mineral oil bath, dried,
and weighed. The experiment was discontinued at the end of a 4-day
period. Based on the weights of the cubes, the average amount of
expansion was found to be 6.13%. It is believed that increased cube
weight was due to swelling of the elastomeric particles from
contact with the mineral oil. FIG. 1 is a photograph comparing one
of the cubes prior to immersion in the mineral oil bath with the
cube after 4 days of immersion. FIG. 2 is a photograph of the three
cubes after 4 days of immersion. The expansion data for the cubes
is set forth in the table below.
TABLE-US-00001 TABLE 1 Class H Texas Lehigh, 1% HR .RTM. 5 Cement
Retarder, 4% CaCl.sub.2, 52.4% Water, and 20% Elastomeric Particles
Elastomeric Time in Cube 1 Cube 2 Cube 3 Sample Particles.sup.1
180.degree. F. Oil Weight Weight Weight Weight (% bwoc) Bath (g)
(g) (g) 14 lb/gal 20 0 days 211.28 214.76 211.86 14 lb/gal 20 1 day
218.23 219.98 218.16 14 lb/gal 20 2 days 221.93 220.45 220.25 14
lb/gal 20 3 days 226.08 222.86 223.62 14 lb/gal 20 4 days 224.78
223.90 228.24 % Expanded 6.39% 4.26% 7.73% % Average Expanded 6.13%
.sup.1The elastomeric particles included in the sample comprised
copolymers of styrene-butadiene elastomeric particles.
EXAMPLE 3
[0036] This example was similar to Example 2 except the
oil-swellable particles were included in the sample extended cement
composition in an amount of 27% bwoc. Accordingly, a sample
extended cement composition was prepared that had a density of 13.5
lb/gal and comprised Class H Texas Lehigh cement, water in an
amount of 56.5% bwoc, block copolymer of styrene-butadiene
elastomeric particles in an amount of 27% bwoc, HR.RTM. 5 cement
retarder in an amount of 1% bwoc, and calcium chloride in an amount
of 4% bwoc.
[0037] This sample extended cement composition was formed into 3
cubes and cured at 140.degree. F. After 24 hours, the set cubes
were weighed. The cubes were then immersed in a mineral oil bath at
180.degree. F. Every 24 hours after immersion in the mineral oil
bath, the set cubes were removed from the mineral oil bath, dried,
and weighed. The experiment was discontinued at the end of a 4-day
period. Based on the weights of the cubes, the average amount of
expansion was found to be 6.13%. It is believed that the increased
cube weight was due to swelling of the elastomeric particles due to
contact with the mineral oil. FIG. 3 is a picture of the cubes
after 4 days of immersion. The expansion data for the cubes is set
forth in the table below.
TABLE-US-00002 TABLE 2 Class H Texas Lehigh, 1% HR .RTM. 5 Cement
Retarder, 4% CaCl.sub.2, 56.5% Water, and 27% Elastomeric Particles
Elastomeric Time in Cube 1 Cube 2 Cube 3 Sample Particles.sup.1
180.degree. F. Oil Weight Weight Weight Weight (% bwoc) Bath (g)
(g) (g) 13.5 lb/gal 27 0 days 209.80 208.60 209.26 13.5 lb/gal 27 1
day 229.66 235.67 234.59 13.5 lb/gal 27 2 days 232.59 234.34 240.87
13.5 lb/gal 27 3 days 232.21 234.76 239.15 13.5 lb/gal 27 4 days
233.29 233.15 240.51 % Expanded 11.19% 11.76% 14.93% % Average
Expanded 12.63% .sup.1The elastomeric particles included in the
sample comprised copolymers of styrene-butadiene elastomeric
particles.
EXAMPLE 4
[0038] This example was performed to determine whether the
expansion of the cubes observed in Examples 2 and 3 was due to
swelling of the elastomeric particles or absorption of the oil by
the cubes. Accordingly, a sample extended cement composition was
prepared that had a density of 14 lb/gal and comprised Class H
Texas Lehigh cement, water in an amount of 69.95% bwoc, HR.RTM. 5
cement retarder in an amount of 1% bwoc, and calcium chloride in an
amount of 4% bwoc. No oil-swellable elastomeric particles were
included in this sample composition.
[0039] This sample extended cement composition was formed into 3
cubes and cured at 140.degree. F. After 24 hours, the set cubes
were weighed. The cubes were then immersed in a mineral oil bath at
180.degree. F. At the end of 24 hours, 48 hours, and 120 hours, the
set cubes were removed from the mineral oil bath, dried, and
weighed. The experiment was discontinued at the end of a 4-day
period. As illustrated in the table below, the cubes absorbed an
insignificant amount of oil.
TABLE-US-00003 TABLE 3 Class H Texas Lehigh, 1% HR .RTM. 5 Cement
Retarder, 4% CaCl.sub.2, and 69.95% Water Elastomeric Time in Cube
1 Cube 2 Sample Particles 180.degree. F. Oil Weight Weight Weight
(% bwoc) Bath (g) (g) 14 lb/gal None 0 day 217.83 232.04 14 lb/gal
None 1 days 217.25 231.43 14 lb/gal None 4 days 217.24 231.21 %
Expanded -0.27% -0.35% % Average Expanded -0.31%
[0040] Therefore, the present invention is well adapted to attain
the ends and advantages mentioned as well as those that are
inherent therein. The particular embodiments disclosed above are
illustrative only, as the present invention may be modified and
practiced in different but equivalent manners apparent to those
skilled in the art having the benefit of the teachings herein.
Furthermore, no limitations are intended to the details of
construction or design herein shown, other than as described in the
claims below. It is therefore evident that the particular
illustrative embodiments disclosed above may be altered or modified
and all such variations are considered within the scope and spirit
of the present invention. In particular, every range of values (of
the form, "from about a to about b," or, equivalently, "from
approximately a to b," or, equivalently, "from approximately a-b")
disclosed herein is to be understood as referring to the power set
(the set of all subsets) of the respective range of values, and set
forth every range encompassed within the broader range of values.
Moreover, the indefinite articles "a" or "an", as used in the
claims, are defined herein to mean one or more than one of the
element that it introduces. Also, the terms in the claims have
their plain, ordinary meaning unless otherwise explicitly and
clearly defined by the patentee.
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