U.S. patent application number 13/602320 was filed with the patent office on 2014-03-06 for methods for maintaining zonal isolation in a subterranean well.
The applicant listed for this patent is Craig Borman, Fatma Daou, Bernard Piot. Invention is credited to Craig Borman, Fatma Daou, Bernard Piot.
Application Number | 20140060836 13/602320 |
Document ID | / |
Family ID | 50184480 |
Filed Date | 2014-03-06 |
United States Patent
Application |
20140060836 |
Kind Code |
A1 |
Daou; Fatma ; et
al. |
March 6, 2014 |
Methods for Maintaining Zonal Isolation in A Subterranean Well
Abstract
A cement for use in wells in which carbon dioxide is injected,
stored or extracted, comprises elastomer particles. In the event of
cement-matrix failure, or bonding failure between the cement/casing
interface or the cement/borehole-wall interface, the elastomer
particles swell when contacted by carbon dioxide. The swelling
seals voids in the cement matrix, or along the bonding interfaces,
thereby restoring zonal isolation.
Inventors: |
Daou; Fatma; (Rio de
Janeiro, BR) ; Borman; Craig; (Camrose, CA) ;
Piot; Bernard; (Paris, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Daou; Fatma
Borman; Craig
Piot; Bernard |
Rio de Janeiro
Camrose
Paris |
|
BR
CA
FR |
|
|
Family ID: |
50184480 |
Appl. No.: |
13/602320 |
Filed: |
September 3, 2012 |
Current U.S.
Class: |
166/293 |
Current CPC
Class: |
C04B 2103/0045 20130101;
E21B 33/14 20130101; C09K 8/467 20130101; C04B 28/02 20130101; C09K
8/42 20130101; C04B 24/26 20130101; C04B 24/2682 20130101; C04B
24/36 20130101; C04B 24/2652 20130101; C04B 40/0675 20130101; C04B
28/02 20130101 |
Class at
Publication: |
166/293 |
International
Class: |
E21B 33/13 20060101
E21B033/13 |
Claims
1. A method for maintaining zonal isolation in a subterranean well
having a borehole in which carbon dioxide is injected, stored,
extracted or naturally present, comprising: (i) installing a
tubular body inside the borehole of the well, or inside a
previously installed tubular body; (ii) pumping aqueous cement
slurry comprising a material that swells when contacted by carbon
dioxide into the borehole; (iii) allowing the cement slurry to set
and harden; (iv) in the event of cement-matrix or bonding failure,
exposing the set cement to wellbore fluids that contain carbon
dioxide; and (v) allowing the material to swell, thereby restoring
zonal isolation.
2. The method of claim 1, wherein the material comprises an
elastomer comprising chlorofluorocarbons,
tetrafluoroethylene-propylene copolymers, ethylene-propylene
copolymers, isobutene-isoprene rubbers, nitrile rubbers,
hydrogenated nitrile butadiene rubbers,
tetrafluoroethylene-perfluorovinyl methyl ether copolymers and
combinations thereof.
3. The method of claim 1, wherein the concentration of the material
in the cement slurry is between about 5 percent and about 50
percent by volume of solid blend (BVOB).
4. The method of claim 1, wherein the average particle size of the
material is between about 10 .mu.m and about 1000 .mu.m.
5. The method of claim 1, wherein the carbon dioxide is
supercritical, wet, dry or dissolved in an aqueous medium.
6. The method of claim 1, wherein the borehole penetrates at least
one fluid-containing reservoir, the reservoir containing fluid with
a carbon dioxide concentration greater than about five moles per
liter.
7. The method of claim 1, wherein the injection of carbon dioxide
into the well is performed as a remedial treatment to restore zonal
isolation.
8. The method of claim 1, wherein the cement comprises one or more
members of the list comprising Portland cement, calcium aluminate
cement, fly ash, blast furnace slag, lime-silica blends, zeolites,
geopolymers, Sorel cements and chemically bonded phosphate
ceramics.
9. The method of claim 1, wherein the cement slurry further
comprises dispersing agents, fluid-loss-control agents, set
retarders, set accelerators, foaming agents, gas generating agents,
antifoaming agents, extenders, weighting agents, lost-circulation
control agents and combinations thereof.
10. The method of claim 1, wherein the tubular body comprises one
or more members of the list comprising drillpipe, casing, liner and
coiled tubing.
11. A method for cementing a subterranean well having a borehole in
which carbon dioxide is injected, stored, extracted or naturally
present, comprising: (i) installing a tubular body inside the
borehole of the well, or inside a previously installed tubular
body; (ii) pumping aqueous cement slurry comprising a material that
swells when contacted by carbon dioxide into the borehole; and
(iii) allowing the cement slurry to set and harden inside the
annular region.
12. The method of claim 11, wherein the material comprises an
elastomer comprising chlorofluorocarbons,
tetrafluoroethylene-propylene copolymers, ethylene-propylene
copolymers, isobutene-isoprene rubbers, nitrile rubbers,
hydrogenated nitrile butadiene rubbers,
tetrafluoroethylene-perfluorovinyl methyl ether copolymers and
combinations thereof.
13. The method of claim 11, wherein the concentration of the
material in the cement slurry is between about 5 percent and about
50 percent by volume of solid blend (BVOB).
14. The method of claim 11, wherein the average particle size of
the material is between about 10 .mu.m and about 1000 .mu.m.
15. The method of claim 11, wherein the carbon dioxide is
supercritical, wet, dry or dissolved in an aqueous medium.
16. The method of claim 11, wherein the borehole penetrates at
least one fluid-containing reservoir, the reservoir containing
fluid with a carbon dioxide concentration greater than about five
moles per liter.
17. The method of claim 11, wherein the injection of carbon dioxide
into the well is performed as a remedial treatment to restore zonal
isolation.
18. The method of claim 11, wherein the cement comprises one or
more members of the list comprising Portland cement, calcium
aluminate cement, fly ash, blast furnace slag, lime-silica blends,
zeolites, geopolymers, Sorel cements and chemically bonded
phosphate ceramics.
19. The method of claim 11, wherein the cement slurry further
comprises dispersing agents, fluid-loss-control agents, set
retarders, set accelerators, foaming agents, gas generating agents,
antifoaming agents, extenders, weighting agents, lost-circulation
control agents and combinations thereof.
20. The method of claim 11, wherein the tubular body comprises one
or more members of the list comprising drillpipe, casing, liner and
coiled tubing.
Description
BACKGROUND
[0001] The statements in this section merely provide background
information related to the present disclosure and may not
constitute prior art.
[0002] This disclosure relates to compositions and methods for
treating subterranean formations, in particular, compositions and
methods for cementing and completing wells into which carbon
dioxide is injected, stored or extracted.
[0003] During the construction of subterranean wells, it is common,
during and after drilling, to place a tubular body in the wellbore.
The tubular body may comprise drillpipe, casing, liner, coiled
tubing or combinations thereof. The purpose of the tubular body is
to act as a conduit through which desirable fluids from the well
may travel and be collected. The tubular body is normally secured
in the well by a cement sheath. The cement sheath provides
mechanical support and hydraulic isolation between the zones or
layers that the well penetrates. The latter function is important
because it prevents hydraulic communication between zones that may
result in contamination. For example, the cement sheath blocks
fluids from oil or gas zones from entering the water table and
polluting drinking water. In addition, to optimize a well's
production efficiency, it may be desirable to isolate, for example,
a gas-producing zone from an oil-producing zone.
[0004] The cement sheath achieves hydraulic isolation because of
its low permeability. In addition, intimate bonding between the
cement sheath and both the tubular body and borehole is necessary
to prevent leaks. However, over time the cement sheath can
deteriorate and become permeable. Alternatively, the bonding
between the cement sheath and the tubular body or borehole may
become compromised. The principal causes of deterioration and
debonding include physical stresses associated with tectonic
movements, temperature changes and chemical deterioration of the
cement.
[0005] These being particularly applicable to wells into which
carbon dioxide is injected (e.g. during Enhanced Oil Recovery
technique), in which carbon dioxide is stored or from which carbon
dioxide is recovered. In addition, there are some oil and gas wells
whose reservoirs naturally contain carbon dioxide.
[0006] A relatively new category of wells involving carbon dioxide
is associated with carbon-sequestration projects. Carbon
sequestration is a geo-engineering technique for the long-term
storage of carbon dioxide or other forms of carbon, for various
purposes such as the mitigation of "global warming". Carbon dioxide
may be captured as a pure byproduct in processes related to
petroleum refining or from the flue gases from power plants that
employ fossil fuels. The gas is then usually injected into
subsurface saline aquifers or depleted oil and gas reservoirs. One
of the challenges is to trap the carbon dioxide and prevent leakage
back to the surface; maintaining a competent and impermeable cement
sheath is a critical requirement.
[0007] The previously disclosed cement systems are concerned with
traditional wells and swell when contacted by water and/or
hydrocarbons; none of these aims at behavior of the cement sheath
when contacted by carbon dioxide.
SUMMARY
[0008] The present disclosure presents improvements by describing
compositions that form a sustainable cement sheath in a
carbon-dioxide environment, and methods by which they may be
prepared and applied in subterranean wells.
[0009] In an aspect, embodiments relate to methods for maintaining
zonal isolation in a subterranean well into which carbon dioxide is
injected, stored, extracted or naturally present. A tubular body is
installed inside the borehole of a well, or inside a previously
installed tubular body. An aqueous cement slurry, containing a
material that swells when contacted by carbon dioxide, is pumped
into the borehole. The cement slurry is allowed to set and harden.
In the event of cement-matrix or bonding failure, the set cement is
exposed to wellbore fluids that contain carbon dioxide. The
material is allowed to swell, thereby restoring zonal
isolation.
[0010] In a further aspect, embodiments relate to methods for
cementing a subterranean well having a borehole, in which carbon
dioxide is injected, stored, extracted or naturally present. A
tubular body is installed inside the borehole of a well, or inside
a previously installed tubular body. An aqueous cement slurry,
containing a material that swells when contacted by carbon dioxide,
is pumped into the borehole. The cement slurry is allowed to set
and harden.
[0011] In yet a further aspect, embodiments relate to methods for
completing a subterranean well having a borehole, in which carbon
dioxide is injected, stored, extracted or naturally present. A
tubular body is installed inside the borehole of a well, or inside
a previously installed tubular body. An aqueous cement slurry,
containing a material that swells when contacted by carbon dioxide,
is pumped into the borehole. The cement slurry is allowed to set
and harden.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 shows the swelling behavior of VITON.TM. elastomer
particles in the presence of nitrogen.
[0013] FIG. 2 shows the swelling behavior of VITON.TM. elastomer
particles in the presence of carbon dioxide.
[0014] FIG. 3 shows the swelling behavior of AFLAS.TM. elastomer
particles in the presence of nitrogen.
[0015] FIG. 4 shows the swelling behavior of AFLAS.TM. elastomer
particles in the presence of carbon dioxide.
DETAILED DESCRIPTION
[0016] At the outset, it should be noted that in the development of
any such actual embodiment, numerous implementation--specific
decisions must be made to achieve the developer's specific goals,
such as compliance with system related and business related
constraints, which will vary from one implementation to another.
Moreover, it will be appreciated that such a development effort
might be complex and time consuming but would nevertheless be a
routine undertaking for those of ordinary skill in the art having
the benefit of this disclosure. In addition, the composition
used/disclosed herein can also comprise some components other than
those cited. In the summary and this detailed description, each
numerical value should be read once as modified by the term "about"
(unless already expressly so modified), and then read again as not
so modified unless otherwise indicated in context. Also, in the
summary and this detailed description, it should be understood that
a concentration range listed or described as being useful,
suitable, or the like, is intended that any and every concentration
within the range, including the end points, is to be considered as
having been stated. For example, "a range of from 1 to 10" is to be
read as indicating each and every possible number along the
continuum between about 1 and about 10. Thus, even if specific data
points within the range, or even no data points within the range,
are explicitly identified or refer to only a few specific, it is to
be understood that the Applicant appreciate and understands that
any and all data points within the range are to be considered to
have been specified, and that the Applicant possessed knowledge of
the entire range and all points within the range.
[0017] As stated earlier, cement systems that form durable cement
sheath in an environment containing carbon dioxide would be
positively received by the industry. The inventors have determine
that cement composition comprising materials that swell in the
presence of carbon dioxide would respond to the industry challenges
as such carbon dioxide swellable compounds will enable the cement
sheath to close its own voids and/or cracks that may appear.
[0018] The carbon dioxide may be wet, dry, supercritical or
dissolved in an aqueous medium. By naturally present, it has to be
understood that the carbon dioxide is present in the borehole at a
minimum concentration of 5 moles per liter of fluid.
[0019] The Applicant has determined that certain elastomers may
fulfill the required swellable capacity in the presence of carbon
dioxide. The elastomers comprise chlorofluorocarbons,
tetrafluoroethylene-propylene copolymers, ethylene-propylene
copolymers, isobutene-isoprene rubbers, nitrile rubbers,
hydrogenated nitrile butadiene rubbers,
tetrafluoroethylene-perfluorovinyl methyl ether copolymers and
combinations thereof.
[0020] In an aspect, embodiments relate to methods for maintaining
zonal isolation in a subterranean well having a borehole, into
which carbon dioxide is injected, stored, extracted or naturally
present. A tubular body is installed inside the borehole of a well,
or inside a previously installed tubular body. An aqueous cement
slurry, containing a material that swells when contacted by carbon
dioxide, is pumped into the borehole. The cement slurry is allowed
to set and harden. In the event of cement-matrix or bonding
failure, the set cement is exposed to wellbore fluids that contain
carbon dioxide. The material is allowed to swell, thereby restoring
zonal isolation.
[0021] In a further aspect, embodiments relate to methods for
cementing a subterranean well having a borehole, in which carbon
dioxide is injected, stored, extracted or naturally present. A
tubular body is installed inside the borehole of a well, or inside
a previously installed tubular body. An aqueous cement slurry,
containing a material that swells when contacted by carbon dioxide,
is pumped into the borehole. The cement slurry is allowed to set
and harden.
[0022] In yet a further aspect, embodiments relate to methods for
completing a subterranean well having a borehole, in which carbon
dioxide is injected, stored, extracted or naturally present. A
tubular body is installed inside the borehole of a well, or inside
a previously installed tubular body. An aqueous cement slurry,
containing a material that swells when contacted by carbon dioxide,
is pumped into the borehole. The cement slurry is allowed to set
and harden.
[0023] For all aspects of the disclosure, the material may be an
elastomer comprising chlorofluorocarbons,
tetrafluoroethylene-propylene copolymers, ethylene-propylene
copolymers, isobutene-isoprene rubbers, nitrile rubbers,
hydrogenated nitrile butadiene rubbers, or
tetrafluoroethylene-perfluorovinyl methyl ether copolymers and
combinations thereof. The concentration of the material may be
between about 5% and 50% by volume of solids in the cement slurry,
also known as "by volume of blend (BVOB)." Or the range may be
between about 10% and 40% BVOB. For optimal performance, the
particle-size distribution of the material may be such that the
average particle size is between about 10 .mu.m and about 1000
.mu.m. The average particle size may also be between about 100
.mu.m and 900 .mu.m.
[0024] Persons skilled in the art will recognize that the present
use of elastomers is different and distinct from their use as
cement extenders (i.e., to reduce the amount of cement or to reduce
the cement-slurry density) or as materials to improve cement
flexibility.
[0025] For all aspects of the disclosure the cement may
additionally comprise one or more members of the list comprising
Portland cement, calcium aluminate cement, fly ash, blast furnace
slag, lime-silica blends, zeolites, geopolymers, Sorel cements or
chemically bonded phosphate ceramics, and mixtures thereof. The
composition shall be pumpable Those skilled in the art will
recognize that a pumpable fluid in the context of well cementing
has a viscosity lower than about 1000 mPa-s at a shear rate of 100
s.sup.-1 at the temperatures to which the fluid is exposed during a
cementing operation, and during the time necessary to place the
composition in the well. Also, the tubular body may comprise one or
more members of the list comprising drillpipe, casing, liner and
coiled tubing. In addition, the borehole may penetrate at least one
fluid-containing reservoir, the reservoir containing fluid with a
carbon dioxide concentration greater than about five moles per
liter.
[0026] The cement slurry may further comprise dispersing agents,
fluid-loss-control agents, set retarders, set accelerators, foaming
agents, gas generating agents, antifoaming agents, extenders,
weighting agents, lost-circulation control agents and combinations
thereof. Other compounds may also be present such as coal,
petroleum coke, graphite or gilsonite and mixtures thereof.
Further, the carbon dioxide swellable elastomers may be couple to
water super absorbent polymers such as those described in EP
1623089 incorporated herein in its entirety. A further association
may be with one or more compounds from the list comprising an
aqueous inverse emulsion of polymer comprising a betaine group,
poly-2,2,1-bicyclo heptene (polynorbornene), alkylstyrene,
crosslinked substituted vinyl acrylate copolymers, diatomaceous
earth, natural rubber, vulcanized rubber, polyisoprene rubber,
vinyl acetate rubber, polychloroprene rubber,
styrene/propylene/diene monomer, brominated
poly(isobutylene-co-4-methylstyrene), butyl rubber,
chlorosulphonated polyethylenes, polyacrylate rubber, polyurethane,
silicone rubber, brominated butyl rubber, chlorinated butyl rubber,
chlorinated polyethylene, epichlorohydrin ethylene oxide copolymer,
ethylene acrylate rubber, ethylene propylene diene terpolymer
rubber, sulphonated polyethylene, fluoro silicone rubbers,
substituted styrene acrylate copolymers and bivalent cationic
compounds or any other particles such as those described in
WO2004/101951 that swells when exposed to liquid hydrocarbons, the
international application being incorporated herein by reference in
its entirety. Further combination may be made with thermoplastic
block polymers including for example styrene-isoprene-styrene
(SIS), styrene-butadiene-styrene (SBS) and mixtures thereof.
Further combination with acid swellable latex may also be
envisaged.
[0027] Persons skilled in the art will recognize that these methods
may be performed during a primary cementing operation or a remedial
cementing operation. The primary cementing operation may be
performed the traditional way (i.e., the slurry is pumped down the
casing and up the annulus) or by "reverse cementing," which
consists of pumping the slurry down the annulus. Persons skilled in
the art will also recognize that the process of carbon dioxide
injection may be a remedial treatment to cause the elastomers to
swell and restore zonal isolation. In this context, carbon dioxide
is injected in the borehole in order to contact the deficient
cement sheath thus triggering the self-reparation of it by
itself.
EXAMPLES
[0028] The following examples serve to further illustrate the
disclosure. The following testing procedure was used for all
examples.
[0029] Several particles of a test elastomer were placed inside a
pressure cell equipped with a window that allows one to observe the
behavior of materials within the cell. The cell supplier is Temco
Inc., located in Houston, Tex. USA. The cell temperature is also
adjustable. A camera captures images from inside the pressure cell,
and image-analysis software is employed to interpret the behavior
of materials inside the cell. After the elastomer particles were
introduced into the cell, the cell was sealed. Either nitrogen or
carbon dioxide gas was then introduced into the cell at 1000 psi
(6.9 MPa), and the camera recorded the sizes of the particles
during exposure periods up to 25 hours at 21.degree. C. (70.degree.
F.).
Example 1
[0030] An O-ring made from a chlorofluorocarbon elastomer
(VITON.TM., available from Parker Seals) was ground into pieces
that were about 200 .mu.m in size. Three particles (P1, P2 and P3)
were placed into the pressure cell, and nitrogen was pumped into
the cell until the pressure reached 1000 psi (6.9 MPa). During the
testing period, the size of the VITON.TM. particles was
periodically monitored. The results, shown in FIG. 1, reveal little
change in the size of the particles during the test period.
[0031] Then, the three VITON.TM. particles were exposed to carbon
dioxide at about 1000 psi (6.9 MPa) and 21.degree. C. As shown in
FIG. 2, the particles swelled by about 35-48 vol % during the test
period.
Example 2
[0032] An O-ring made from a fluoroelastomer (AFLAS.TM., available
from Seals Eastern) was ground into pieces that were about 200
.mu.m in size. Four particles (Particles 1, 2, 3 and 4) were placed
into the pressure cell, and nitrogen was pumped into the cell until
the pressure reached 1000 psi (6.9 MPa). During the testing period,
the size of the AFLAS.TM. particles was periodically monitored. The
results, shown in FIG. 3, reveal little change in the size of the
particles during the test period.
[0033] Then, the four AFLAS.TM. particles were exposed to carbon
dioxide at about 1000 psi (6.9 MPa) and 21.degree. C. As shown in
FIG. 4, the particles swelled by about 25-37 vol % during the test
period
[0034] Although various embodiments have been described with
respect to enabling disclosures, it is to be understood that the
preceding information is not limited to the disclosed embodiments.
Variations and modifications that would occur to one of skill in
the art upon reading the specification are also within the scope of
the disclosure, which is defined in the appended claims.
* * * * *