Note: Descriptions are shown in the official language in which they were submitted.
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RESIN-BASED SEALANT COMPOSITIONS COMPRISING CEMENT KILN
DUST AND METHODS OF USE
BAC KG ROUND
[0001] The present invention relates to resin-based sealant compositions and,
more
particularly, in certain embodiments, to resin-based sealant compositions that
comprise
cement kiln dust ("CKD") and associated methods of use in servicing well
bores.
100021 Sealant compositions may be used in a variety of subterranean
applications.
For example, in subterranean well construction, a conduit (e.g., pipe string,
casing, liners,
expandable tubulars, etc.) may be run into a well bore 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 method, a sealant composition may be pumped into an
annulus
between the walls of the well bore and the exterior surface of the pipe string
disposed
therein. The sealant composition may set in the annular space, thereby forming
an annular
sheath of hardened, substantially impermeable seal (i.e., a sealant sheath)
that may support
and position the pipe string in the well bore and may bond the exterior
surface of the pipe
string to the subterranean formation. or the inside of a larger conduit. Among
other things,
the sealant sheath surrounding the pipe string functions to prevent the
migration of fluids in
the annulus, as well as protecting the pipe string from corrosion. Sealant
compositions also
may be used in remedial-cementing methods, for example, to seal voids in pipe
strings or
cement sheaths, to seal highly permeable formation zones or fractures, to
place a cement
plug, and the like. As used herein the term "void" refers to any type of
space, including
fractures, holes, cracks, channels, spaces, and the like. Such voids may
include: holes or
cracks in the pipe strings; holes, cracks, spaces, or channels in the sheath;
and very small
spaces (commonly referred to as "micro-annuli") between the interior surface
of the sealant
sheath and the exterior surface of the conduit or between the outer surface of
the sealant
sheath and the formation or inside surface of a larger conduit. Sealing such
voids may
prevent the undesired flow of fluids (e.g., oil, gas, water, etc.) and/or tine
solids into, or
from, the well bore. Sealant compositions also may be used in surface
applications, for
example, construction cementing.
[0003] A variety of ditierent sealant compositions, including non-cementitious
sealants, such as resin-basal sealant compositions have been used in these
primary- and
secondary-cementing methods. Resin-based sealant compositions may comprise,
for
example, a liquid hardenable agent component and a hardening agent component.
Because
resin-based sealant compositions may have increased flexibility and toughness
as compared
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to conventional cement compositions the resin-based sealant composition may be
used, for
example, in applications Where increased stresses and/or increased number of
stress cycles
may be encountered. For example, resin-based sealant compositions may have
applicability
in cementing methods performed in shale formations as wells drilled in these
types of
formations may require multiple fracturing stages requiring the sealant
compositions to have
sufficient flexibility and toughness to withstand repeated hydraulic stress
and thermal cycles.
In addition, resin-based sealant compositions may also be placed into the well
bore to plug a
void in the conduit (e.g., the pipe string) or cement sheath or a void that
may have formed
between the sheath and a wall of the well bore or the conduit. While resin-
based sealant
compositions may be used instead of conventional cementitious-based sealant
compositions
in certain applications, drawbacks exist with use of such sealant
compositions, including the
high cost of the resins, for example.
2
SUMMARY
[0004] An embodiment of the present invention provides a method comprising:
providing a resin-based sealant composition comprising a liquid hardenable
resin component
and kiln dust; and allowing the resin-based sealant composition to harden.
[0005] Another embodiment of the present invention provides a method of
forming
a seal in a subterranean formation comprising: introducing a resin-based
sealant composition
into a subterranean formation, wherein the resin-based sealant composition
comprises a
liquid hardenable resin component and cement kiln dust; and allowing the resin-
based
sealant composition to harden in the subterranean formation.
[0006] Another embodiment of the present invention provides a resin-based
sealant
composition comprising a liquid hardenable resin component and cement kiln
dust.
[0007] The features and advantages of the present invention will be readily
apparent
to those skilled in the art.
[0007a] In accordance with another embodiment of the present invention, there
is
provided a resin-based sealant composition comprising: a liquid hardenable
resin
component; and kiln dust, wherein the liquid hardenable resin component
comprises a
hardenable resin and a hardening agent, the hardening agent selected from the
group
consisting of an aliphatic amine, an aliphatic tertiary amine, an aromatic
amine, a
cycloaliphatic amine, a heterocyclic amine, an amido amine, a polyamide, a
polyethyl amine.
a polyether amine, a polyoxyalkylene amine, a carboxylic anhydride,
triethylenetetraamine,
ethylene diamine, N-cocoalkyltrimethylene, isophorone diamine, N-aminophenyl
piperazine,
imidazoline, 1,2-diaminocyclohexane, a polyetheramine, diethyltoluenediamine,
4,4'-
diaminodiphenyl methane, methyltetrahydrophthalic anhydride, hexahydrophthalic
anhydride, maleic anhydride, polyazelaic polyanhydride, phthalic anhydride,
and any
combination thereof.
3
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DESCRIPTION OF PREFERRED EMBODIMENTS
[0008] The present invention relates to resin-based sealant compositions and,
more
particularly, in certain embodiments, to resin-based sealant compositions that
comprise
cement kiln dust ("CKD") and associated methods of use in servicing well
bores. One of the
many potential advantages of the methods and compositions of the present
invention is that
the CKD may be used as a non-hydrating filler material to lower the
consumption of the
more expensive components (e.g., hardenable resin component, etc.) that are
typically used
In resin-based sealant compositions. Yet another potential advantage is that
the CKD may
aid the sealing of voids such as cracks that may form in the hardened sealant
composition.
By way of example, the CK.D may hydrate and harden upon contact with water,
far example,
to counteract the potential formation of voids (e.g., cracks, micro-annuli,
etc.) that may form
in the hardened sealant composition.
[0009] Embodiments of the present invention disclose resin-based sealant
compositions comprising a liquid hardenable resin component and CKD. In some
13 embodiments, the resin-based sealant composition may further comprise a.
liquid hardening
agent component tbr facilitating the set of the hardenable resin component. In
other
erntxxiiments, the liquid hardenable resin component may auto-catalyze and not
require the
hardenable resin component for setting. The resin-based sealant compositions
may be used
in a number different subterranean applications in which the sealant
composition may be
introduced into a subterranean tbrination and allowed to harden. One example
of a
subterranean application includes primary-cementing methods in which the resin-
based
sealant composition may be allowed to harden in a well-bare annulus. Another
example of a
subterranean application includes remedial-cementing methods in which the
resin-based
sealant composition may be allowed, for example, to harden and seal voids in
pipe strings or
cement sheaths, to seal highly permeable formation zones or fractures, to
place a cement
plug, and the like,
[00101 in some embodiments, the liquid hardenable resin component of the resin-
based sealant composition may comprise a hardenable resin, an optional
solvent, and an
optional aqueous diluent. or carrier fluid. As used herein, the term "resin"
refers to any of a
number of physically similar polymerized synthetics or chemically modified
natural resins
including thermoplastic materials and thermosetting materials. Examples of
hardenable
resins that may be used in the liquid hardenable resin component include, but
are not limited
-to, epoxy-based resins, novolak resins, polyepoxide resins, phenol-aldehyde
resins, urea-
aldehyde resins, urethane resins, phenolic -resins, furan resins,
furaWfurfuryl alcohol resins,
phenolicilatex resins, phenol formaldehyde resins, bisphenol A diglycidyl
ether resins,
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butoxymethyl butyl glycidyl ether resins. bisphenol A-epichlorohydrin resins,
bisphenol P
resins, glycidyl ether resins, polyester resins and hybrids and copolymers
thereof,
polyurethane resins and hybrids and ctvolymets thereof, acrylate resins, and
mixtures
thereof. Some suitable resins, such as epoxy resins, may be cured with an
internal catalyst or
activator so that when pumped downhole, they may be cured using only time and
temperature. Other suitable resins, such as furan resins generally require a
time-delayed
catalyst or an external catalyst to help activate the polymerization of the
resins if the cure
temperature is low (i.e., less than 250 4 but will cure under the effect of
time and
temperature if the formation temperature is above about 250 F. preferably
above about
300'F. it is within the ability of one skilled, in the art, with the benefit
of this disclosure, to
select a suitable resin for use in embodiments of the present invention and to
determine
whether a catalyst is required to trigger curing. One resin that may be used
in particular
embodiments of the present invention is the consolidation agent commercially
available from
lialliburton Energy Services, Inc., of Duncan, Okla., under the trade name
"EXPED1TETht."
1001 111 Selection of a suitable resin may be affected by the temperature of
the.
subterranean formation to which the composition will be introduced. By way of
example,
for subterranean formations having a bottom hole static temperature ("BUST')
ranging from
about 60 F to about 250 F, two-component epoxy-based resins comprising a
hardenable
resin component and a hardening agent component containing specific hardening
agents may
be preferred. For subterranean formations having a BUST ranging from about 300
F to
about 600 F, a tbran-based resin may be preferred. For subterranean
formations having a
BUST ranging from about 200 F to about 400 F, either a phenolic-based resin or
a one-
component HT epoxy-based resin may be suitable. For subterranean formations
having a
BUST of at least about 175 F, a phenol/phenol formaldehydeifinftiryl alcohol
resin may also
be suitable.
[0012] Generally, the hardenable resin may be included in the liquid
hardenable
resin component in an amount in a range of from about 5% to about 100% by
volume of the
liquid hardenable resin component. In particular embodiments, the hardenable
resin may be
included in the liquid .hardenable resin component in an amount in a range of
from about
75% to about 100% by volume of the liquid hardenable resin component. It is
within the
ability of one skilled in the art with the benefit of this disclosure to
determine how much of
the hardenable resin may be needed to achieve the desired results. Factors
that may affect
this decision include the type of .hardenable resin and liquid hardening agent
used in a
particular application.
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[0013] In some embodiments, a solvent may he added to the resin to reduce its
viscosity for ease of handling, mixing and transferring.
However, in particular
embodiments, it may be desirable not to use such a solvent for environmental
or safety
reasons. It is within the ability done skilled in the art with the benefit of
this disclosure to
determine if and how much solvent may be needed to achieve a viscosity
suitable to the
subterranean conditions of a particular application. Factors that may affect
this decision
include geographic location of the well, the surrounding weather conditions,
and the desired
long-term stability of the resin-based sealant composition.
[0014] Generally, any solvent that is compatible with the hardenable resin and
that
achieves the desired viscosity effect may be suitable for use in the liquid
hardenable resin
component of the resin-based sealant composition. Suitable solvents may
include, but are
not limited to, polyethylene glycol, butyl lactate, dipropylene glycol methyl
ether,
dipropylene glycol dimethyl ether, dimethyl thrmamide, diethylefieglycol
methyl ether,
ethyleneglycol butyl ether, diethylerteglycol bitty?' ether, propylene
carbonate, dlimonene,
fatty acid methyl esters, and combinations thereof. Selection of an
appropriate solvent may
be dependent on the hardenable resin chosen. With the benefit of this
disclosure, the
selection of an appropriate solvent, should be within the ability of one
skilled in the are In
some embodiments, the amount of the solvent used in the liquid hardenable
resin component
may be in the range of about 0.1% to about 30% by weight of the liquid
hardenable resin
component. Optionally, the liquid hardenable resin component may be heated to
reduce its
viscosity, in place of, or in addition to, using a solvent.
[0015] Generally, the liquid hardenable resin component may be included in
embodiments of the resin-based sealant composition in an amount in a range
from about 5%
to about 90% by volume of the resin-based sealant composition. In particular
embodiments,
the liquid hardenable resin component may be included in the resin-based
sealant
composition in an amount in a -range of from about 50% to about 75% by volume
of the
resin-based sealant composition.
[0016] in some embodiments, the resin-based sealant composition may further
comprise a liquid hardening agent component comprising a hardening agent and
an optional
silane coupling agent. As used herein, "hardening agent" refers to any
substance capable of
transforming the hardenable resin into a hardened, consolidated mass. Examples
of suitable
hardening agents include, but are not limited to, aliphatic amines, aliphatic
tertiary amines,
aromatic amines, cycloaliphatic amines, heterocyclic amines, amido amines, -
polyarnicies,
polyethyl amines, polyether amines, polyoxyalkylene amines, carboxylic
anhydrides,
trie,thylenetetraamine, ethylene diamine, N-cocoalkyltrimethylene, isophorone
diamine., N-
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aminophenyl piperazine im idazo line. 1,2-
diaminocyclohexane, polyetheramine,
diethyltoluenediamine, 4,4'-diamirtodiphenyl methane,
.methyltetrahydrophlhalic anhydride,
hexahydrophthalic anhydride, maleic anhydride, polyazelaic polyanhydride,
phthalic
anhydride, and. combinations thereof Specific examples of suitable hardening
agents may
include, but are not limited to, ETIIACURE 100, available from Albemarle Corp.
of Baton
Rouge, La.., and JEFFAM1Ne D-230, available from Huntsman Corp. of 'The
Woodlands,
Tex. The hardening agent may be included in the liquid hardening agent
component in an
amount sufficient to at least partially harden the resin composition. In some
embodiments of
the present invention, the hardening agent used may be included in the liquid
hardening
agent component in an amount in a range of from about 5% to about 100% by
volume of the
liquid hardening agent component. In other embodiments, the hardening agent
used may he
included in the liquid hardening agent component in an amount in a range of
from about
50% to about 75% by volume of the liquid hardening agent component.
E00171 In some embodiments the hardening agent may comprise a mixture of
hardening agents selected to impart particular qualities to the resin-based
sealant
composition. For example, in particular embodiments, the hardening agent may
comprise a
fast-setting hardening agent and a slow-setting hardening agent. As used
herein, "fast-setting
hardening agent" and "slow-setting hardening agent" do not imply any specific
ntte at which
the agents set a hardenable min; instead, the terms merely indicate the
relative rates at
which the hardening agents initiate hardening of the resin. Whether a
particular hardening
agent is considered fast-setting or slow-setting may depend on the other
hardening agent(s)
with which it is used. In a particular embodiment, ETHACURe 100 may be used as
a
slow-setting hardening agent and .1EFFAMINE, D-230, may be used .as a fast-
setting
hardening agent. In some embodiments, the ratio of fast-setting hardening
agent to slow-
setting hardening agent may be selected to achieve a desired behavior of
liquid hardening
agent component. For example, in some embodiments, the Fast-setting hardening
agent may
be included in the liquid hardening agent component in a ratio of
approximately 1:5, by
volume, with the slow-setting hardening agent. With the benefit of this
disclosure, one of
ordinary skill in the art should be able to select the appropriate ratio of
hardening agents for
use in a particular application.
190181 The liquid hardening agent component of the resin-based sealant
composition
may also include an optional silane coupling agent. The slime coupling agent
may be used,
Among other things, to act as a mediator to help bond the resin to OW, the
surface of the
subterranean formation, andior the surface of the well bore. Examples of
suitable siiane
coupling agents include, but are not limited to, N-2-(aminoethyl)-3-
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arninopropyltrimethoxysilane; 3-glycidoxypropyltrimethoxysilane; gamma-
aminopropyltriethoxysi lane; N-beta-
(arninocth yI)-garnma-aminopropyltri methox ys i lanes;
aminoethyl-N-beta-(aminoethyl)-gamma-aminopropyl-trimethoxysilanes; gamma-
ureidopropyl-triethoxysilanes; beta-(3-4 epoxy-cyclohexyl)-ethyl-
trimethoxysilane; gamma-
glycidoxypropyltrimethoxysilanes; vinyltrichlorosilane; vinyltris (beta-
methoxyethoxy)
silane; vinyltriethoxysilane; vinyltrimethoxysilane; 3-
metacryloxypropyltrimethoxysi1ane;
beta-(3,4 epoxycyclohexyl)-ethyltrirnethoxysilane;
rilycidoxypropyltrimethoxysilane; r-
glycidoxypropylmethylidiethoxysilane; N-beta-
(arn inoethyl)-r-arainopmpy I-
trimethoxysilane; N-beta-
(aminoethyl)-r-am inopropylmethyldi met hoxysi lane; 3-
arninopropyl-triethoxysilane; N-phenyl-r-a.minopropyltrimethoxysilane; r-
tnercaptopropy I tri methoxysi I ane; r-ch
loropropyltrimethoxysi lane; vinyltrichlorosilane;
viny kris (beta-methoxyethoxy) silane;
vinyltrimethoxysi lane; r-
metacryloxypropyltrimethoxysilane; beta-(3,4 epoxycyclohexyl)-
ethyltrimethoxysila; r-
glyci doxypropyltrimethoxys i lane; r-g I
ycidoxypropyl methylidiethoxysi lane ; N-beta-
(it m noethyl)-r-aminopropyltri methox ys la ne; N-beta-(aini
noethyl)-r-
ami nopropy I methyld imethoxys i lane; r-arn
inopropyl triethoxysi lane; N-phenyl-r-
aininopmpyltrimethoxysilanc; r-mmaptopropy I trimethoxysilane; r-
chloropropyltrimethoxysilant; N[3-(trimethoxysilyt)propyll-ethylenediainine:
substituted
silanes where one or more of the substitutions contains a different functional
group; and
combinations thereof. Generally, the silane coupling agent may be included in
the liquid
hardening agent component in an amount capable of sufficiently bonding the
resin to the
particulate. In some embodiments of the present invention, the silane coupling
agent may be
included in the liquid hardening agent component in an amount in a range of
from about
0.1% to about 95% by volume of the liquid hardening agent component. In other
embodiments, the silane coupling agent may be included in the liquid hardening
agent
component in an amount in a range of from about 5% to about 50% by volume of
the liquid
hardening agent component,
[0019] A liquid carrier fluid may also be used in the liquid hardening agent
component to, among other things, reduce the viscosity of the liquid hardening
agent:
component for ease of handling, mixing and tmnsfening. However, in some
embodiments, it
may be desirable, for environmental or safety reasons, not to use a liquid
carrier fluid. Any
suitable carrier fluid that is compatible with the liquid hardening agent
component and
achieves the desired viscosity effects may be suitable for use in the present
invention. Some
suitable liquid carrier fluids are those having high flash points (e.g., above
about I 251)
because of, among other things, environmental and safety concerns; such
solvents may
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include, but are not limited to, polyethylene glycol, butyl lactate,
butylglycidyl ether,
dipropylene glycol methyl ether, dipropylene glycol dimethyl ether, dimethyl
formamide,
diethyleneglycol methyl ether, ethyletteglycol butyl ether, diethyleneeycol
butyl ether,
propylene carbonate, crlimortene, fatty acid methyl esters, and combinations
thereof. in
particular embodimenis, selection of an appropriate liquid carrier fluid may
be dependent on,
inter att., the resin composition chosen.
[0020] Generally, the liquid hardening agent component may be included in the
resin-based sealant composition in an amount in a range of from about 1% to
about 50% by
volume of the resin-based sealant composition. In particular embodiments, the
liquid
hardening agent component may he included in the resin-based sealant
composition in an
amount in a range of from about. 5% to about 25% by volume of the resin-based
sealant
composition. In particular erribodiments, the amount of liquid hardening agent
composition
may be selected to impart a desired elasticity or compressibility to a
resulting well-bore seal
Generally, the lower the amount of hardening agent present in the resin-based
sealant
composition, the greater the elasticity or compressibility of a resulting well-
bore seal. With
the benefit of this disclosure, it should be within the skill of one or
ordinary skill in the art to
select an appropriate amount of hardening agent to achieve a desired
elasticity or
compressibility for a particular application.
[0021] In some embodiments, the resin-based sealant compositions may further
comprise CKD, which is a material generated in the manufacture of cement. CKD,
as that
term is used herein, refers to a partially calcined kiln feed which is removed
from the gas
stream and collected, for example, in a dust collector during the manufacture
of cement.
Usually, large quantities of CKD are collected in the production of cement
that are
commonly disposed of as waste. Disposal of the CKD as waste can add
undesirable costs to
the manufitcture of the cement, as well as the environmental concerns
associated with its
disposal. The chemical analysis of CKD from various cement manufactures varies
-depending on a number of factors, including the particular kiln feed, the
efficiencies of the
cement production operation, and the associated dust: collection systems. CKD
generally
may comprise a variety of oxides, such as Si01, A I20:e Fe20s, CaO, MgO, SO),
Na20, and
K20. The term "CKD" is used herein to mean cement kiln dust made as described
above and
equivalent forms of cement kiln dust made in other ways.
[0022] In accordance with embodiments of the present invention, the CKD may be
used, among other things, as a non-hydrating filler material to lower the
consumption of the
more expensive components (e.g., hardenable resins, etc.) that are used in the
resin-based
sealant compositions. While the CKD is a cementitious component that sets and
hardens in
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the presence of water, the CKD should be non-hydrated when mixed with the
liquid
hardenahle resin component and optionally the liquid hardening agent component
as the
resin-based sealant composition may be non-aqueous, for example. In this
manner, the resin-
based sealant composition may be placed into a subterranean formation and
allowed to
harden therein with the CKD remaining non-hydrated. Because the CKD is present
in the
hardened composition, it is believed that the CKD may help counteract the
potential
formation of cracks in the hardened composition and/or micro-annulus that may
form
between the hardened composition and the pipe string or the well-bore wall. In
general, the
CKD is capable of setting and hardening when contacted by aqueous fluids to
inhibit fluid
flow through the crack and/or micro-annulus. Accordingly, the CKD 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 embodiments of the resin-
based sealant
compositions.
E0023] Generally, the CKD may be included in the resin-based sealant
compositions
13 in an amount in a range of from about 1% to about 60% by volume of the
resin-based sealant
composition. In particular embodiments, the CKD may be included in the resin-
based
sealant compositions in an amount in a range of from about 20% to about 40% by
volume of
the resin-based sealant composition. In specific embodiments, the CKD may be
present in
an amount ranging between any of and/or including any of about of about 1%,
about 10%,
about 20%, about 30%, about 40%, about 50%, or about 60% by volume of the
resin-based
sealant composition. One of ordinary skill in the art, with the benefit of
this disclosure, will
recognize the appropriate amount of CKD to include for a chosen application.
[0024] While the preceding description describes CKD, the present invention is
broad enough to encompass the use of other partially calcined kiln feeds. For
example,
embodiments of the resin-based sealant compositions may comprise lime kiln
dust, which is
a material that is generated during the -manufacture of lime. The term "lime
kiln dust"
typically refers to a partially calcined kiln feed which can be removed from
the gas stream
and collected, for example, in a dust collector during the manufacture of
lime. The chemical
analysis of lime kiln dust from various lime manufactures varies depending on
a number of
factors, including the particular limestone or dolomitic limestone feed, the
type of kiln, the
mode of operation of the kiln, the efficiencies of the lime production
operation, and the
associated dust collection systems. Lime kiln dust generally may comprise
varying amounts
of fret lime and free magnesium, lime stone, and/or dolomitic limestone and a
variety of
oxides, such as Si02, A1703, Fe2O3, Ca0, MgO, SO3, Na20, and K20, and other
components, such as chlorides.
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10025] In some embodiments, the resin-based sealant compositions may further
comprise a weighting material. As used herein, the term "weighting material"
refers to any
particulate matter added to the resin-based sealant composition to increase or
lower density.
Examples of weighting materials for lowering density include, but are not
limited to. hollow
microspheres. Examples of suitable hollow microspheres include, but are not
limited to,
hollow mineral glass spheres, such as "SPIIERELITErm" available from
lialliburton Energy
Services of Duncan, Okla.; silica and alumina cenospheres, such as "CENOLITEt"
available
from Microspheres S.A. of South Africa; hollow glass microspheres, such as
"SaYFCIIIATErm" available from the 3M Company of St. Paul, Minn.; ceramic
microspheres, such as "1.-1.IGHT SPHERESTM" available from the 3M Company of
St.
Paul, Minn.; polymeric microspheres. such as "EXMNCEe" available from Akzo
Nobel of
The Netherlands; and plastic .inicrospheres, such as "LUBRA-BEADS*" available
from
Halliburton Energy Services, Inc. of Duncan, Okla. Examples of suitable
weighting
materials for increasing density include, but are not limited to, silica,
ilmenite, hematite,
13 barite, Portland cement, manganese tetraoxide, and combinations thereof
Specific examples
of weighting materials for increasing density include, but are not limited to,
MICROSANDim, a crystalline silica weighting material, and HI-DENSE*, a
hematite
weighting material, both available from flalliburton Energy Services, Inc. of
Duncan, Okla.
[0026] The mean particulate sizes of the weighting material may generally
range
from about 2 nanometers to about 3000 microns in diameter: however, in certain
circumstances, other mean particulate sizes may be desired and will be
entirely suitable for
practice of the present. invention. It should be understood that the term
"particulate," as used
in this disclosure, includes all known shapes of materials, including
substantially spherical
materials, fibrous materials, polygonal materials (such as cubic materials.),
and mixtures
thereof In particular embodiments, the particulate size of the weighting
material may be
selected to impart a desired viscosity to the resin-based sealant composition.
Moreover, in
particular embodiments, weighting materials having differentparticulate sizes
may be mixed
to achieve a desired viscosity of the min-based sealant composition.
[0027] Generally, the weighting material may be included in the resin-based
sealant
composition in an amount in a range of from about 1% to about 60 4 by volume
of the resin-
based sealant composition. In particular embodiments, the weighting material
may be
included in the resin-based sealant composition in an amount in a range of
from about 20%
to about 40% by volume or the resin-based sealant composition.
[00281 in some embodiments, the resin-based sealant compositions may further
comprise swellable particles. As used herein, the term "swellable particle"
refers to any
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particle that swells upon contact with oil, gas, a combination of oil and gas,
and/or an
aqueous fluid (e.g., water). Swellable particles suitable for use in
embodiments of the
present invention may generally swell by up to about 50% of their original
size at the
surface. Under downhole conditions, the amount of swelling may vary depending
on the
conditions presented. For example, in some embodiments, the amount of swelling
may be at
least 10% under downhole conditions. in particular embodiments, the amount of
swelling
may be up to about 50% under downhole conditions. However, as those of
ordinary skill in
the art, with the benefit of this disclosure, will appreciate, the actual
amount of swelling
when the swellable particles are included in a resin-based sealant composition
may depend
on the concentration of the swellable particles included in the composition,
among other
factors. In accordance with particular embodiments of the present invention,
the swellable
particles may be included in the resin-based sealant composition, for example,
to counteract
the formation of Cracks in a resultant well-bore seal and/or micro-annulus
between the well
bore plug and the pipe string or the lbrmation. In general, the swellable
particles are capable
of swelling when contacted by one or more of the previously mentioned fluids
to inhibit fluid
.flow through the crack and/or micro-annulus. Accordingly, the swellable
particles may
prevent and/or reduce the loss of zonal isolation in spite of the formation of
cracks and/or
micm-annulus, potentially resulting in an improved annular seal for the resin-
based sealant
compositions.
100291 Some specific examples of suitable.swellable elastomers include, but
are not
limited to, natural rubber, acrylate butadiene rubber, polyacrylate rubber,
isoprene rubber,
eholoroprene rubber, butyl rubber (11R), brominated butyl rubber (BUR),
chlorinated butyl
rubber (CUR), chlorinated polyethylene (CMICPE), neoprene rubber (CR), styrene
butadiene
copolymer rubber (SBR), 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 (INMQ), silicone rubbers
(VMQ), poly
2,2,1-bicyclo heptene (polynorborneane), and alkylstyrene. One example of a
suitable
swellable elastomer comprises a block copolymer of a styrene butadiene rubber.
Examples
of suitable elastomers that swell When contacted by oil include, but are not
limited to, nitrile
rubber (NBR), hydrogenated nitrile rubber (FINBR, HNS), fluoro rubbers (FKM),
perfluoro
rubbers (EMM), tetratiumethylenelpropylene MEI% isobutylene maleic anhydride.
Other
swellable elastomers that behave in a similar fashion with respect to oil or
aqueous fluids
also may be suitable for use in particular embodiments of the present
invention.
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Furthermore, combinations of suitable swellable elastomers may also be used in
particular
embodiments of present invention.
[0030] Some specific examples of suitable water-swellable polymers, include,
but
are not limited, to starch-polyacrylate acid grail copolymer and salts
thereof, polyethylene
oxide polymer, carboxymethyl cellulose type polymers. polyacrylamide,
polytacrylic acid)
and salts thereof poly(acrylic acid-co-acrylamide) and salts thereof; graft-
poly(ethylene
oxide) of polytacrylic acid) and salts thereof, poly(2-hydroxyetbyl
inethacrylate), poly(2-
hydroxypropyl methacrylate), and combinations thereof Other water-swellable
polymers
that behave in a similar fashion with respect to aqueous fluids also may be
suitable for use in
particular embodiments of the present invention. In certain embodiments, the
water-
swellable polymers may be crosslinked and/or lightly crosslinked. Those of
ordinary skill in
the art, with the benefit of this disclosure, will be able to select an
appropriate swellable
elastomer and/or water-swellable polymer for use in particular embodiments of
the resin-
based sealant compositions of the present invention based on a variety of
factors, including
13 the particular application in which the composition will be used and the
desired swelling
characteristics.
[0031] Generally, the swellable particles may be included in the resin-based
sealant
compositions in an amount sufficient to provide the desired mechanical
properties. In some
embodiments, the swellable particles may be present in the resin-based sealant
compositions
ht an amount up to about 25% by weight of the hardenable resin. In some
embodiments, the
swellable particles may be present in the resin-based sealant compositions in
a ranee of about
5% to about 25% by weight of the hardenable rain. In some embodiments, the
swellable
particles may be present in the resin-based sealant compositions in a range of
about 15% to
about 20% by weight of the hardenable resin.
[0032] In addition, the swellable particles that may be utilized may have a
wide
variety of shapes and sizes of individual particles suitable for use in
accordance with
embodiments of the present invention. fly way of example, the swellable
particles 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, pellets, tablets, or
any other physical shape. In some embodiments, the swellable particles may
have a mean
particle size in the range of about 5 microns to about 1,500 microns. In some
embodiments,
the swellable particles may have a mean 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.
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[0033] In some embodiments of the present invention, additional solid
materials
may also be included in the min-based sealant composition to enhance the
strength,
hardness, and/or toughness of the resulting well-bore seal. These solid
materials may
include both natural and man-made materials, and may have any shape,
including, but not
limited to, beaded, cubic, bar-shaped, cylindrical, or mixtures therevf, and
may be in any
form including, but not limited to flake or fiber form. Suitable materials may
include, but
are not limited to, cellulose fibers, carbon fibers, glass fibers, mineral
fibers, plastic fibers
(e.g., polypropylene and polyacrylic nitrite fibers), metallic fibers, metal
shavings, Kellar
fibers, basalt fibers, wollastonite, micas (e.g., phlogopites and muscovites),
and mixtures
thereof. In some embodiments, nanoparticles and/or nanotibers may also be
included in the
resin-based sealant composition, wherein the nanoparticies and/or natmfibers
have at least
one dimension less than .1 micron and, alternatively, less than about 100
rtanometers.
[0034] Carbon fibers suitable for use in particular embodiments of the present
invention include high tensile modulus carbon fibers which have a high tensile
strength. In
some embodiments, the tensile modulus of-the carbon fibers may exceed 180 GPa,
and the
tensile strength of the carbon fibers may exceed 3000 MPa. Generally, the
fibers may have a
mean length of about 1 mm or less. In some embodiments, the mean length of the
carbon
fibers is from about 50 to about 500 microns. In particular embodiment, the
carbon fibers
have a mean length in the range of from about 100 to about 200 microns. In
particular
embodiments, the carbon fibers may be milled carbon fibers. Suitable,
commercially
available carbon fibers include, but are not limited to, "AGM-94" and "AGM-99"
carbon
fibers both available from Asbury Graphite Mills, Inc., of Asbury, NJ.
[0035] Metallic fibers suitable for use in particular embodiments of the
present
invention may include non-amorphous (i.e., crystalline) metallic fibers. In
particular
embodiments, the non-amorphous metallic fibers may be obtained by cold drawing
steel
wires (ix., steel wool). Suitable metallic fibers include, but are not limited
to, steel fibers.
Generally, the length and diameter of the metallic fibers may be adjusted such
that the fibers
are flexible and easily dispersible in the resin-based sealant composition,
and the resin-based
sealant composition is easily pumpable.
[0036] These additional solid materials may be present in the resin-based
sealant
composition of the present invention individually or in combination.
Additionally, the solid
materials of the present invention may be present in the resin-based sealant
composition in a
variety of lengths and/or aspect ratios. .A person having ordinary skill in.
the art, with the
benefit of this disclosure, will recognize the mixtures of type, length,
and/or aspect ratio to
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use to achieve the desired properties of a resin-based sealant composition for
a particular
application.
[00371 In particular embodiments of the present invention, the liquid
hardenable
resin component, optional liquid hardening agent component, and CKD, as well
as any of the
additional optional additives (e.g., weighting material, swellable particles,
additional solid
materials) may be either batch-mixed or mixed on-the-fly. As used herein, the
term "on-the-
fly" is used herein to mean that a flowing stream is continuously introduced
into another
flowing stream so that the streams are combined and mixed while continuing to
flow as a
single stream as part of the on-going treatment. Such mixing may also be
described as "real-
time" mixing. On-the-fly mixing, as opposed to batch or partial batch mixing,
may reduce
waste and simplify subterranean treatments. This is due, in part, to the fact
that, in particular
embodiments, if the components are mixed and then circumstances dictate that
the
subterranean treatment be stopped or postponed, the mixed components may
become
unusable. By having the ability to rapidly shut down the mixing of streams on-
the-fly in
13 such embodiments, unnecessary waste may be avoided, resulting in, inter
elle, increased
efficiency and cost. savings. However, other embodiments of the present
invention may
allow for batch mixing of the resin-based sealant composition. in these
embodiments, the
resin-based sealant composition may be sufficiently stable to allow the
composition to be
prepared in advance of its introduction into the well bore without the
composition becoming
unusable if not promptly introduced into the well bore.
[0038] Generally, embodiments of the resin-based sealant compositions of the
present invention may be used for any of a variety different purposes in which
the resin-
based sealant composition may be prepared and allowed to harden. In some
embodiments,
the resin-based sealant composition may be introduced into a subterranean
formation and
allowed to harden. As used herein, introducing the resin-based sealant
composition into a
subterranean formation includes introduction into any portion of the
subterranean formation,
including, without limitation, into a well bore drilled into the subterranean
formation, into a
near well bore region surrounding the well bore, or into both. The resin-based
sealant
composition may be allowed to harden in the subterranean formation for a
number of
purposes including, without limitation: to isolate the subterranean formation
from a portion
of the well bore; to support a conduit in the well bore; to plug a void in the
conduit; plug a
void in a cement sheath disposed in an annulus of the well bore; to plug a
perforation; to
plug void ("e.g., micro-annulus) between the cement sheath and the conduit; to
prevent the
loss of aqueous or nonaqueous drilling fluids into loss circulation zones such
as a void,
vugular zone, or fracture; to plug a well for abandonment purposes; to form a
temporary plug
CA 02882817 2015-02-23
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to divert treatment fluids; as a chemical packer to be used as a fluid in
front of cement slurry
in cementing operations; or to seal an annulus between the well bore and an
expandable pipe
or pipe string. For instance, the resin-based sealant composition may
withstand substantial
amounts of pressure, e.g., the hydrostatic pressure of a drilling fluid or
cement slurry,
without being dislodged or extruded. The resin-based sealant composition may
set into a
flexible, resilient and tough material, which may prevent further fluid losses
when circulation
is. resumed. The min-based sealant composition may also form a non-flowing,
intact mass
inside the loss-circulation zone. This mass plugs the zone and inhibits loss
of subsequently
pumped drilling fluid, which allows for .further
100391 In primary-cementing embodiments, for example, embodiments of the resin-
based sealant composition may be introduced into a well-bore annulus such as a
space
between a wall of a well bore and a conduit (e.g., pipe strings, liners)
located in the well bore
or between the conduit and a larger conduit in the well bore. The resin-based
sealant
composition may be allowed to harden to form an annular sheath of the hardened
13 composition in the well-bore annulus. Among other things, the hardened
composition
formed by the resin-based sealant composition may form a barrier, preventing
the migration
of fluids in the well bore. The hardened composition also may, ibr example,
support the
conduit in the well bore and/or form a bond between the well-bore wall and the
conduit.
[0040] In some embodiments, the conduit may also be cemented into a well-bore
annulus by utilizing what is known as a reverse-cementing method. The reverse-
cementing
method comprises displacing the resin-based sealant composition into the
annulus between
the conduit and the annulus between an existing string, or an open hole
section of the
wellbore. As the resin-based sealant composition is pumped down the annular
space, drilling
fluids ahead of the min-based sealant composition are displaced around the
lower ends of
the conduit and up the inner diameter of the conduit and out at the surface.
The fluids ahead
of the resin-based sealant composition may also be displaced upwardly through
a work string
that has been run into the inner diameter of the conduit and sealed off at its
lower end.
Because the work string has a smaller inner diameter, fluid velocities in the
work string will
be hither and will more efficiently transfer the cuttings washed out of the
annulus during
placement of the resin-based sealant composition.. In an embodiment, a small
amount of
resin-based sealant composition will be pumped into the conduit and the work
string. As
soon as a desired amount of resin-based sealant composition has been pumped
into the
annulus, the work string may be pulled out of its seal receptacle and excess
resin-based
sealant composition that has entered the work string can be reverse-circulated
out the lower
end of the work string to the surface.
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[0041] In remedial-cementing embodiments, a resin-based sealant composition
may
he used, for example, in squeeze-cementing operations or in the placement of
cement plugs.
By way of example, the resin-based sealant composition may be placed in a well
bore to plug
voids, such as holes or cracks in the pipe strings; holes, cracks, spaces, or
channels in the
sheath; and very small spaces (commonly referred to as "micro-annuli") between
the sheath
and the exterior surface of the pipe or well-bore wall.
[0042] It should be understood that the compositions and methods are described
in
terms of "comprising," "containing," or "including" various components or
steps, the
compositions and methods can also "consist essentially of' or "consist or the
various
components and steps. 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.
[0043] For the sake of brevity, only certain ranges are explicitly disclosed
herein.
However, ranges from any lower limit may be combined with any upper limit to
recite a
range not explicitly recited, as well as, ranges from any lower limit may be
combined with
any other lower limit to recite a range not explicitly recited, in the same
way, ranges from
any upper limit may be combined with any other upper limit to recite a range
not explicitly
recited. Additionally, whenever a numerical range with a lower limit and an
upper limit is
disclosed, any number and any included range falling within the range are
specifically
disclosed. 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 to set forth every number and range
encompassed within
the broader range of values even if not explicitly recited. Thus, every point
or individual
value may serve as its own lower or upper limit combined with any other point
or individual
value or any other lower or upper limit, to recite a range not explicitly
recited.
[0044] 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. Although individual embodiments are discussed, the
invention covers
all combinations of all those embodiments. Furthermore, no limitations are
intended to the
details of construction or design herein shown, other than as described in the
claims below.
Also, the terms in the claims have their plain, ordinary meaning unless
otherwise explicitly
and clearly defined by the patentee. It is therefore evident that the
particular illustrative
embodiments disclosed above may be altered or modified and all such variations
arc
considered within the scope of the appended claims. If there is any conflict
in the usages of
17
CA 02882817 2016-09-12
a word or term in this specification and one or more patent(s) or other
documents that may
be herein referred to, the definitions that are consistent with this
specification should be
adopted.
18
