U.S. patent application number 10/383184 was filed with the patent office on 2004-10-28 for methods and compositions for consolidating proppant in fractures.
Invention is credited to Barton, Johnny A., Isenberg, O. Marlene, Nguyen, Philip D..
Application Number | 20040211561 10/383184 |
Document ID | / |
Family ID | 32961294 |
Filed Date | 2004-10-28 |
United States Patent
Application |
20040211561 |
Kind Code |
A1 |
Nguyen, Philip D. ; et
al. |
October 28, 2004 |
Methods and compositions for consolidating proppant in
fractures
Abstract
Improved methods and compositions for consolidating proppant in
subterranean fractures are provided. In accordance with the methods
of the invention, proppant particles coated with a hardenable
bisphenol A-epichlorohydrin resin composition are mixed with a
gelled liquid fracturing fluid and the fracturing fluid is pumped
into a subterranean zone. The fracturing fluid forms one or more
fractures in the subterranean zone and deposits the proppant
particles coated with the resin composition therein. Thereafter,
the hardenable resin composition on the proppant particles is
allowed to harden by heat and consolidate the proppant particles
into degradation resistant permeable packs. The hardenable
bisphenol A-epichlorohydrin resin compositions of the invention are
storable for long periods of time before use.
Inventors: |
Nguyen, Philip D.; (Duncan,
OK) ; Barton, Johnny A.; (Marlow, OK) ;
Isenberg, O. Marlene; (Duncan, OK) |
Correspondence
Address: |
Robert A. Kent
Halliburton Energy Services
2600 South 2nd Street
Duncan
OK
73536
US
|
Family ID: |
32961294 |
Appl. No.: |
10/383184 |
Filed: |
March 6, 2003 |
Current U.S.
Class: |
166/280.2 ;
166/281; 166/288; 166/295; 166/300; 507/219; 507/233; 507/260;
507/924; 523/131 |
Current CPC
Class: |
C09K 8/805 20130101;
E21B 43/26 20130101; Y10S 507/924 20130101; C09K 2208/26 20130101;
Y10T 428/2998 20150115; C09K 8/90 20130101; C09K 8/68 20130101;
E21B 43/267 20130101 |
Class at
Publication: |
166/280.2 ;
166/281; 166/288; 166/295; 166/300; 523/131; 507/219; 507/233;
507/260; 507/924 |
International
Class: |
E21B 043/267; E21B
033/138 |
Claims
What is claimed is:
1. An improved method of forming one or more fractures in a
subterranean zone penetrated by a well bore and consolidating
proppant particles therein, the subterranean zone having a
temperature above about 225.degree. F. comprising the steps of: (a)
providing proppant particles coated with a hardenable resin
composition comprised of a liquid bisphenol A-epichlorohydrin
resin, a 4,4'-diaminodiphenyl sulfone hardening agent dissolved in
a solvent selected from the group consisting of dimethyl sulfoxide
and a dimethyl formamide, a silane coupling agent and a surfactant
for facilitating the coating of the resin on the proppant particles
and for causing the resin to flow to the contact points between
adjacent resin coated proppant particles; (b) providing a gelled
liquid fracturing fluid; (c) pumping said gelled liquid fracturing
fluid into said subterranean zone to form said one or more
fractures and to deposit said proppant particles therein; (d)
mixing said proppant particles coated with said hardenable resin
composition with said fracturing fluid pumped in accordance with
step (c) whereby said proppant particles coated with said
hardenable resin composition are suspended therein; (e) terminating
steps (c) and (d) when said proppant particles coated with said
hardenable resin composition have been deposited in said one or
more fractures; and (f) allowing said hardenable resin composition
on said resin composition coated proppant particles to harden by
heat and consolidate said proppant particles into one or more
degradation resistant permeable packs.
2. The method of claim 1 wherein said liquid bisphenol
A-epichlorohydrin resin is present in said hardenable resin
composition in an amount in the range of from about 40% to about
65% by weight of said composition.
3. The method of claim 1 wherein said 4,4'-diaminodiphenyl sulfone
hardening agent is dissolved in said dimethyl sulfoxide or dimethyl
formamide solvent in an amount of about 40% by weight of said
solvent.
4. The method of claim 1 wherein said 4,4'-diaminodiphenyl sulfone
hardening agent dissolved in said dimethyl sulfoxide or dimethyl
formamide solvent is present in said hardenable resin composition
in an amount in the range of from about 15% to about 50% by weight
of said composition.
5. The method of claim 1 wherein said silane coupling agent in said
hardenable resin composition is selected from the group consisting
of N-2-(aminoethyl)-3-aminopropyltrimethoxysilane,
3-glycidoxypropyltrimetho- xysilane and
n-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane.
6. The method of claim 1 wherein said silane coupling agent in said
hardenable resin composition is
n-beta-(aminoethyl)-gamma-aminopropyl-tri- methoxysilane.
7. The method of claim 1 wherein said silane coupling agent is
present in said hardenable resin composition in an amount in the
range of from about 0.1% to about 3% by weight of said
composition.
8. The method of claim 1 wherein said surfactant for facilitating
the coating of said resin on said proppant particles and for
causing said resin to flow to the contact points between adjacent
resin coated proppant particles is selected from the group
consisting of an ethoxylated nonyl phenol phosphate ester, mixtures
of one or more cationic surfactants and one or more non-ionic
surfactants and a C.sub.12-C.sub.22 alkyl phosphonate
surfactant.
9. The method of claim 1 wherein said surfactant is a
C.sub.12-C.sub.22 alkyl phosphonate surfactant.
10. The method of claim 1 wherein said surfactant is present in
said hardenable resin composition in an amount in the range of from
about 0.1% to about 10% by weight of said composition.
11. The method of claim 1 which further comprises a hydrolyzable
ester for breaking gelled fracturing fluid films on said proppant
particles.
12. The method of claim 11 wherein said hydrolyzable ester is
selected from the group consisting of a mixture of
dimethylglutarate, dimethyladipate and dimethylsuccinate, sorbitol,
catechol, dimethylthiolate, methyl salicylate, dimethylsuccinate
and terbutylhydroperoxide.
13. The method of claim 11 wherein said hydrolyzable ester is a
mixture of dimethylglutarate, dimethyladipate and
dimethylsuccinate.
14. The method of claim 11 wherein said hydrolyzable ester is
present in said hardenable resin composition in an amount in the
range of from about 0.1% to about 5%.
15. The method of claim 1 which further comprises a high flash
point diluent for reducing the viscosity of said hardenable resin
composition.
16. The method of claim 15 wherein said high flash point diluent is
dipropylene glycol methyl ether.
17. The method of claim 15 wherein said high flash point diluent is
present in said resin composition in an amount in the range of from
about 1% to about 40% by weight of said composition.
18. An improved method of forming one or more fractures in a
subterranean zone penetrated by a well bore and consolidating
proppant particles therein, the subterranean zone having a
temperature above about 225.degree. F. comprising the steps of: (a)
providing a liquid hardenable resin composition comprised of a
liquid bisphenol A-epichlorohydrin resin, a 4,4'-diaminodiphenyl
sulfone hardening agent dissolved in a solvent selected from the
group consisting of dimethyl sulfoxide and dimethyl formamide, an
n-beta-(aminoethyl)-gamma-aminopropyltrimethoxysil- ane coupling
agent, a C.sub.12-C.sub.22 alkyl phosphate surfactant, a mixture of
dimethylglutarate, dimethyladipate and dimethylsuccinate
hydrolyzable esters and a dipropylene glycol methyl ether diluent;
(b) providing a source of dry proppant particles; (c) providing a
gelled liquid fracturing fluid comprised of water and a gelling
agent selected from the group consisting of guar gum, guar gum
derivatives and cellulose derivatives; (d) pumping said gelled
liquid fracturing fluid into said subterranean zone to form said
one or more fractures therein and to place said proppant particles
therein; (e) coating said hardenable resin composition onto said
dry proppant particles conveyed from said source thereof to form
hardenable resin composition coated proppant particles; (f) mixing
said hardenable resin composition coated proppant particles formed
in step (e) with said fracturing fluid pumped in accordance with
step (d) whereby said hardenable resin composition coated proppant
particles are suspended therein; (g) terminating steps (d), (e) and
(f) when said hardenable resin composition coated proppant
particles have been placed in said one or more fractures; and (h)
allowing said hardenable resin composition on said hardenable resin
composition coated proppant particles to harden by heat and
consolidate said proppant particles into one or more degradation
resistant permeable packs.
19. The method of claim 18 wherein said liquid bisphenol
A-epichlorohydrin resin is present in said hardenable resin
composition in an amount of about 50% by weight of said
composition.
20. The method of claim 18 wherein said 4,4'-diaminodiphenyl
sulfone hardening agent is dissolved in said dimethyl sulfoxide
solvent in an amount of about 25% by weight of said solvent.
21. The method of claim 18 wherein said 4,4'-diaminodiphenyl
sulfone hardening agent dissolved in said dimethyl sulfoxide
solvent is present in said hardenable resin composition in an
amount of about 25% by weight of said composition.
22. The method of claim 18 wherein said silane coupling agent is
present in said hardenable resin composition in an amount of about
1% by weight of said composition.
23. The method of claim 18 wherein said surfactant is present in
said hardenable resin composition in an amount of about 5% by
weight of said composition.
24. The method of claim 18 wherein said hydrolyzable ester mixture
is present in said hardenable resin composition in an amount in the
range of from about 2% by weight of said composition
25. The method of claim 18 wherein said proppant particles are
graded sand.
26. The method of claim 18 wherein said water in said gelled liquid
fracturing fluid is selected from the group consisting of fresh
water and salt water.
27. The method of claim 18 wherein said gelling agent is present in
said fracturing fluid in an amount in the range of from about 0.1%
to about 1% by weight of water therein.
28. The method of claim 18 wherein said gelled liquid fracturing
fluid further comprises a cross-linking agent selected from the
group consisting of alkali metal borates, borax, boric acid and
compounds capable of releasing multivalent metal ions in aqueous
solutions.
29. The method of claim 28 wherein said cross-linking agent is
present in said fracturing fluid in an amount in the range of from
about 0.01% to about 1% by weight of water therein.
30. The method of claim 18 wherein said gelled liquid fracturing
fluid further comprises a delayed viscosity breaker selected from
the group consisting of alkali metal and ammonium persulfates which
are delayed by being encapsulated in a material which slowly
releases said breaker, alkali metal chlorites, alkali metal
hypochlorites and calcium hypochlorites.
31. The method of claim 30 wherein said delayed viscosity breaker
is present in said fracturing fluid in an amount in the range of
from about 1% to about 5% by weight of water therein.
32. A hardenable resin composition for coating proppant particles
comprising: a hardenable resin comprised of a liquid bisphenol
A-epichlorohydrin resin; a 4,4-diaminodiphenyl sulfone hardening
agent dissolved in a solvent selected from the group consisting of
dimethyl sulfoxide and dimethyl formamide; a silane coupling agent;
and a surfactant for facilitating the coating of the resin on the
proppant particles and for causing the resin to flow to the contact
points between adjacent resin coated proppant particles.
33. The composition of claim 32 wherein said liquid bisphenol
A-epichlorohydrin resin is present in an amount in the range of
from about 40% to about 65% by weight of said composition.
34. The composition of claim 32 wherein said 4,4'-diaminodiphenyl
sulfone hardening agent is dissolved in said dimethyl sulfoxide or
dimethyl formamide solvent in an amount of about 40% by weight of
said solvent.
35. The composition of claim 32 wherein said 4,4'-diaminodiphenyl
sulfone hardening agent dissolved in said dimethyl sulfoxide or
dimethyl formamide solvent is present in an amount in the range of
from about 15% to about 50% by weight of said composition.
36. The composition of claim 32 wherein said silane coupling agent
is selected from the group consisting of
N-2-(aminoethyl)-3-aminopropyltrime- thoxysilane,
3-glycidoxypropyltrimethoxysilane and n-beta-(aminoethyl)-gam-
ma-aminopropyl-trimethoxysilane.
37. The composition of claim 32 wherein said silane coupling agent
is n-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane.
38. The composition of claim 32 wherein said silane coupling agent
is present in an amount in the range of from about 0.1% to about 3%
by weight of said composition.
39. The composition of claim 32 wherein said surfactant for
facilitating the coating of said resin on said proppant particles
and for causing said resin to flow to the contact points between
adjacent resin coated proppant particles is selected from the group
consisting of an ethoxylated nonyl phenol phosphate ester, mixtures
of one or more cationic surfactants and one or more non-ionic
surfactants and a C.sub.12-C.sub.22 alkyl phosphonate
surfactant.
40. The composition of claim 32 wherein said surfactant is
comprised of a C.sub.12-C.sub.22 alkyl phosphonate surfactant.
41. The composition of claim 32 wherein said surfactant is present
in an amount in the range of from about 0.1% to about 10% by weight
of said composition.
42. The composition of claim 32 which further comprises a
hydrolyzable ester for breaking gelled fracturing fluid films on
said proppant particles.
43. The composition of claim 42 wherein said hydrolyzable ester is
selected from the group consisting of a mixture of
dimethylglutarate, dimethyladipate and dimethylsuccinate, sorbitol,
catechol, dimethylthiolate, methyl salicylate, dimethylsuccinate
and terbutylhydroperoxide.
44. The composition of claim 42 wherein said hydrolyzable ester is
a mixture of dimethylglutarate, dimethyladipate and
dimethylsuccinate.
45. The composition of claim 42 wherein said hydrolyzable ester is
present in said hardenable resin composition in an amount in the
range of from about 0.1% to about 5%.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to methods and storable
hardenable resin compositions for forming one or more fractures in
high temperature subterranean zones and consolidating proppant
particles therein.
[0003] 2. Description of the Prior Art
[0004] Hydrocarbon producing wells are often stimulated by
hydraulic fracturing treatments. In hydraulic fracturing, a viscous
fracturing fluid which also functions as a carrier fluid is pumped
into a subterranean zone to be fractured at a rate and pressure
such that one or more fractures are formed in the zone. Proppant
particles, e.g., graded sand, for propping the fractures open are
suspended in the fracturing fluid so that the proppant particles
are deposited in the fractures when the fracturing fluid is broken.
That is, a viscosity breaker is included in the fracturing fluid
whereby the fracturing fluid reverts to a thin fluid which is
returned to the surface. The proppant particles deposited in the
fractures function to prevent the fractures from closing so that
conductive channels are formed through which produced hydrocarbons
can readily flow.
[0005] In order to prevent the subsequent flow-back of the proppant
particles as well as loose or incompetent fines with fluids
produced from the subterranean zone, the proppant particles have
heretofore been coated with a hardenable resin composition which is
caused to harden and consolidate the proppant particles in the zone
into permeable packs. However, when the subterranean zone has a
temperature above about 200.degree. F., and it produces
hydrocarbons at exceptionally high rates or undergoes reoccurring
stresses due to frequent well shutoffs and openings, the hardened
resin composition and the permeable proppant particle packs
consolidated therewith rapidly deteriorate which allows proppant
particles and formation fines to flow-back with produced formation
fluids. The flow-back of the proppant particles and formation fines
is very detrimental in that it erodes metal goods, plugs piping and
vessels and causes damage to valves, instruments and other
production equipment.
[0006] Another problem encountered in the use of prior hardenable
resin compositions for coating proppant particles is that the
hardenable resin composition or components thereof have had short
shelf lives. In addition, the hardenable resin composition
components have heretofore had low flash points making them
dangerous to use. Also, when the prior hardenable resin
compositions or components thereof have been stored at high ambient
temperatures, the compositions or components have quickly hardened
making them unsuitable for use.
[0007] Thus, there are needs for improved methods and storable
hardenable resin compositions for consolidating proppant particles
in subterranean fractures whereby the permeable packs of
consolidated proppant particles formed are resistant to degradation
by high production rates, stress cycling and/or thermal
degradation. Further, there are needs for improved hardenable resin
compositions that are premixed and have long shelf lives and high
flash points.
SUMMARY OF THE INVENTION
[0008] The present invention provides improved methods and
compositions for consolidating proppant in fractures formed in high
production rate, high stress and/or high temperature subterranean
zones which meet the needs described above and overcome the
deficiencies of the prior art. The hardenable resin compositions of
this invention are hardened by heat and consolidate resin coated
proppant particles at temperatures above about 200.degree. F. into
degradation resistant permeable packs which do not allow proppant
flow-back and the production of formation fines with formation
fluids.
[0009] An improved method of the present invention for forming one
or more fractures in a subterranean zone having a temperature above
about 200.degree. F. penetrated by a well bore and consolidating
proppant particles therein is comprised of the following steps.
Proppant particles coated with a hardenable resin composition are
provided. The hardenable resin composition is comprised of a liquid
bisphenol A-epichlorohydrin resin, a 4,4'-diaminodiphenyl sulfone
hardening agent dissolved in a dimethyl sulfoxide or dimethyl
formamide solvent, a silane coupling agent and a surfactant for
facilitating the coating of the resin on the proppant particles and
for causing the resin composition to flow to the contact points
between adjacent coated proppant particles. Optionally, a
hydrolyzable ester for breaking gelled fracturing fluid films on
the proppant particles can be included in the hardenable resin
composition. A high flash point diluent such as dipropylene glycol
methyl ether can also optionally be included in the hardenable
resin composition to reduce its viscosity to a desirable level for
ease of pumping during use. A gelled liquid fracturing fluid is
also provided which is pumped into the subterranean zone to form
one or more fractures and to deposit the proppant particles
therein. The proppant particles coated with the hardenable resin
composition are mixed with the fracturing fluid being pumped
whereby the proppant particles coated with the hardenable resin
composition are suspended therein. When the proppant particles
coated with the hardenable resin composition have been deposited in
the one or more fractures formed, the pumping of the fracturing
fluid and the mixing of the proppant particles coated with the
hardenable resin composition with the fracturing fluid are
terminated. Thereafter, the hardenable resin composition on the
resin composition coated proppant particles is allowed to harden by
heat and consolidate the proppant particles into one or more
degradation resistant permeable packs.
[0010] Another improved method of this invention for forming one or
more fractures in a subterranean zone penetrated by a well bore and
consolidating proppant particles therein, the subterranean zone
having a temperature above about 200.degree. F. is comprised of the
following steps. A liquid hardenable resin composition is provided
comprised of a liquid bisphenol A-epichlorohydrin resin, a
4,4'-diaminodiphenyl sulfone hardening agent dissolved in a
dimethyl sulfoxide solvent, an
n-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane coupling
agent, a C.sub.12-C.sub.22 alkyl phosphate surfactant, a mixture of
dimethylglutarate, dimethyladipate and dimethylsuccinate esters,
and a dipropylene glycol methyl ether diluent. A source of dry
proppant particles and a gelled liquid fracturing fluid comprised
of water and a gelling agent selected from the group consisting of
guar gum, guar gum derivatives and cellulose derivatives are also
provided. The gelled liquid fracturing fluid is pumped into the
subterranean zone to form the one or more fractures therein and to
place the proppant particles therein. The hardenable resin
composition is coated onto the dry proppant particles conveyed from
the source thereof to form hardenable resin composition coated
proppant particles. The hardenable resin composition coated
proppant particles are mixed with the fracturing fluid pumped into
the subterranean zone whereby the hardenable resin composition
coated proppant particles are suspended therein. When the
hardenable resin composition coated proppant particles have been
placed in the one or more fractures formed in the subterranean
zone, the pumping of the gelled fracturing fluid, the coating of
the hardenable resin composition onto the dry proppant particles
and the mixing of the hardenable resin composition coated proppant
particles formed with the fracturing fluid are terminated.
Thereafter, the hardenable resin composition on the hardenable
resin composition coated proppant particles is allowed to harden by
heat and consolidate the proppant particles into one or more
degradation resistant permeable packs.
[0011] The features and advantages of the present invention will be
readily apparent to those skilled in the art upon a reading of the
description of preferred embodiments which follows.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0012] The present invention provides improved methods of forming
one or more fractures in a subterranean zone penetrated by a well
bore and consolidating proppant particles therein, the subterranean
zone having a temperature above about 200.degree. F. comprising the
following steps. Proppant particles coated with a hardenable resin
composition comprised of a liquid bisphenol A-epichlorohydrin
resin, a 4,4'-diaminodiphenyl sulfone hardening agent dissolved in
a dimethyl sulfoxide or dimethyl formamide solvent, a silane
coupling agent and a surfactant for facilitating the coating of the
resin on the proppant particles and for causing the resin to flow
to the contact points between adjacent resin coated proppant
particles are provided. Optionally, a hydrolyzable ester for
breaking gelled fracturing fluid films on the proppant particles
can be included in the hardenable resin composition. A high flash
point diluent such as dipropylene glycol methyl ether can also
optionally be included in the hardenable resin composition to
reduce its viscosity to a desirable level for ease of pumping
during operation. A gelled liquid fracturing fluid is also provided
which is pumped into the subterranean zone to form the one or more
fractures and to deposit the proppant particles therein. The
proppant particles coated with the hardenable resin composition are
mixed with the fracturing fluid being pumped into the subterranean
zone whereby the proppant particles coated with the hardenable
resin composition are suspended therein. When the proppant
particles coated with the hardenable resin composition have been
deposited in the one or more fractures, the pumping of the gelled
liquid fracturing fluid and the mixing of the proppant particles
coated with the hardenable resin composition with the fracturing
fluid are terminated. Thereafter, the hardenable resin composition
on the resin composition coated proppant particles are allowed to
harden by heat and consolidate the proppant particles into one or
more high production rate, high stress and/or high temperature
degradation resistant permeable packs.
[0013] The proppant particles utilized in accordance with the
present invention are generally of a size such that formation
particulate solids that migrate with produced fluids are prevented
from being produced from the subterranean zone. Various kinds of
proppant particles can be utilized including graded sand, bauxite,
ceramic materials, glass materials, walnut hulls, polymer beads and
the like. Generally, the proppant particles have a size in the
range of from about 2 to about 400 mesh, U.S. Sieve Series. The
preferred proppant is graded sand having a particle size in the
range of from about 10 to about 70 mesh, U.S. Sieve Series.
Preferred sand particle size distribution ranges are one or more of
10-20 mesh, 20-40 mesh, 40-60 mesh or 50-70 mesh, depending on the
particular size and distribution of formation solids to be screened
out by the consolidated proppant particles.
[0014] Liquid bisphenol A-epichlorohydrin resin is readily
available from a number of commercial sources. For example, a
suitable such resin is commercially available from the Resin
Resolution Corporation of Houston, Tex. Upon curing by heat in a
subterranean zone, the bisphenol A-epichlorohydrin resin forms an
insoluble mass that is highly resistant to high production rate,
high stress and/or high temperature degradation, e.g., the cured
resin resists thermal degradation at temperatures up to 400.degree.
F. The bisphenol A-epichlorohydrin resin is generally present in
the hardenable resin composition in an amount in the range of from
about 40% to about 65% by weight of the hardenable resin
composition, and more preferably in an amount of about 50%.
[0015] The liquid hardening agent for hardening the bisphenol
A-epichlorohydrin resin at temperatures above about 200.degree. F.
is comprised of 4,4'-diaminodiphenyl sulfone dissolved in dimethyl
sulfoxide or dimethyl formamide solvent and is present in the
hardenable resin composition in an amount in the range of from
about 15% to about 50% by weight of the composition, and more
preferably in an amount of about 25%. The solvent contains the
4,4'-diaminodiphenyl sulfone in an amount of about 40% by weight of
the solvent.
[0016] Examples of silane coupling agents which can be utilized in
the hardenable resin composition include, but are not limited to,
N-2-(aminoethyl)-3-aminopropyltrimethoxysilane,
3-glycidoxypropyltrimetho- xysilane and
n-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane. Of these,
n-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane is preferred.
The silane coupling agent is included in the hardenable resin
composition in an amount in the range of from about 0.1% to about
3% by weight of the composition and more preferably in an amount of
about 1%.
[0017] Various surfactants for facilitating the coating of the
resin on the proppant particles and for causing the resin to flow
to the contact points between adjacent resin coated proppant
particles can be utilized in the hardenable resin composition.
Examples of the surfactants include, but are not limited to,
ethoxylated nonyl phenol phosphate ester surfactants, mixtures of
one or more cationic surfactants and one or more non-ionic
surfactants and a C.sub.12-C.sub.22 alkyl phosphonate surfactant.
Of these, a C.sub.12-C.sub.22 alkyl phosphonate surfactant is
preferred. The surfactant is included in the hardenable resin
composition in an amount in the range of from about 0.1% to about
10% by weight of the composition and more preferably in an amount
of about 5%.
[0018] Examples of hydrolyzable esters which can optionally be
included in the hardenable resin composition include, but are not
limited to, a mixture of dimethylglutarate, dimethyladipate and
dimethylsuccinate, sorbitol, catechol, dimethylthiolate, methyl
salicylate, dimethylsuccinate and terbutylhydroperoxide. Of these,
a mixture of dimethylglutarate, dimethyladipate and
dimethylsuccinate are preferred. When utilized, the hydrolyzable
ester is included in the liquid hardenable resin composition in an
amount in the range of from about 0.1% to about 53% by weight of
the composition and more preferably in an amount of about 2%.
[0019] A high flash point diluent that can optionally be included
in the hardenable resin composition is dipropylene glycol methyl
ether. When used, the diluent is present in an amount of about 1%
to about 40% by weight of the composition.
[0020] The liquid hardenable resin composition of this invention
can be premixed and stored at atmospheric conditions, e.g.,
temperatures up to 120.degree. F. without significant viscosity
increase or deterioration. As mentioned above, the liquid
hardenable resin composition hardens at temperatures above about
200.degree. F. and can be utilized in wells having temperatures in
the range of from about 200.degree. F. to about 350.degree. F. and
higher. The liquid hardenable resin composition has a safe high
flash point above 170.degree. F.
[0021] Another improved method of forming one or more fractures in
a subterranean zone penetrated by a well bore and consolidating
proppant particles therein, the subterranean zone having a
temperature above about 200.degree. F. is comprised of the
following steps. A liquid hardenable resin composition is provided
comprised of a liquid bisphenol A-epichlorohydrin resin, a
4,4'-diaminodiphenyl sulfone dissolved in a dimethyl sulfoxide
solvent, an n-beta-(aminoethyl)-gamma-aminopropyltrime- thoxysilane
coupling agent, a C.sub.12-C.sub.22 alkyl phosphate surfactant, a
mixture of dimethylglutarate, dimethyladipate and dimethylsuccinate
hydrolyzable esters and a dipropylene glycol methyl ether diluent.
A source of dry proppant particles and a gelled liquid fracturing
fluid are also provided. The gelled liquid fracturing fluid is
comprised of water and a gelling agent selected from the group
consisting of guar gum, guar gum derivatives and cellulose
derivatives. The gelled liquid fracturing fluid is pumped into the
subterranean formation to form the one or more fractures therein
and to place the proppant particles therein. The hardenable resin
composition is coated onto the dry proppant particles conveyed from
the source thereof to form hardenable resin composition coated
proppant particles. The hardenable resin composition coated
proppant particles are mixed with the fracturing fluid being pumped
whereby the hardenable resin composition coated proppant particles
are suspended therein. When the hardenable resin composition coated
proppant particles have been placed in the one or more fractures by
the fracturing fluid, the pumping of the fracturing fluid, the
coating of the hardenable resin composition onto the dry proppant
particles and the mixing of the hardenable resin composition coated
proppant particles formed with the fracturing fluid are terminated.
Thereafter, the hardenable resin composition on the hardenable
resin composition coated proppant particles is allowed to harden by
heat and consolidate the proppant particles into one or more high
production rate, high stress and/or high temperature degradation
resistant permeable packs.
[0022] The bisphenol A-epichlorohydrin resin, the
4,4'-diaminodiphenyl sulfone hardening agent dissolved in a
dimethyl sulfoxide solvent, the silane coupling agent, the
surfactant, the hydrolyzable esters and the dipropylene glycol
methyl ether diluent are present in the hardenable resin
composition in the same amounts as described above.
[0023] The water in the gelled liquid fracturing fluid is selected
from the group consisting of fresh water and salt water. The term
"salt water" is used herein to mean unsaturated salt solutions and
saturated salt solutions including brines and seawater.
[0024] The gelling agent in the fracturing fluid is generally
present in an amount in the range of from about 0.01% to about 3%
by weight of water therein and more preferably in an amount of
about 0.1% to about 1%.
[0025] The gelled liquid fracturing fluid can include a
cross-linking agent for increasing the viscosity of the fracturing
fluid. Examples of suitable cross-linking agents include, but are
not limited to, alkali metal borates, borax, boric acid and
compounds capable of releasing multivalent metal ions in aqueous
solutions. When used, the cross-linking agent is included in the
fracturing fluid in an amount in the range of from about 0.001% to
about 5% by weight of water therein and more preferably in an
amount of about 0.01% to about 1%.
[0026] The fracturing fluid generally also includes a delayed
viscosity breaker which functions to reduce the viscosity of the
fracturing fluid and cause the resin composition coated proppant
particles suspended in the fracturing fluid to be deposited in the
fractures. Examples of delayed viscosity breakers which can be
utilized include, but are not limited to, alkali metal and ammonium
persulfates which are delayed by being encapsulated in a material
which slowly releases the breaker, alkali metal chlorites, alkali
metal hypochlorites and calcium hypochlorite. When used, the
delayed viscosity breaker is included in the fracturing fluid in an
amount in the range of from about 1% to about 5% by weight of water
therein.
[0027] A preferred method of this invention for forming one or more
fractures in a subterranean zone penetrated by a well bore and
consolidating proppant particles therein, the subterranean zone
having a temperature above about 225.degree. F. comprises the steps
of: (a) providing proppant particles coated with a hardenable resin
composition comprised of a liquid bisphenol A-epichlorohydrin
resin, a 4,4'-diaminodiphenyl sulfone hardening agent dissolved in
a solvent selected from the group consisting of dimethyl sulfoxide
and dimethyl formamide, a silane coupling agent and a surfactant
for facilitating the coating of the resin on the proppant particles
and for causing the resin to flow to the contact points between
adjacent resin coated proppant particles; (b) providing a gelled
liquid fracturing fluid; (c) pumping the gelled liquid fracturing
fluid into the subterranean zone to form the one or more fractures
and to deposit the proppant particles therein; (d) mixing the
proppant particles coated with the hardenable resin composition
with the fracturing fluid pumped in accordance with step (c)
whereby the proppant particles coated with the hardenable resin
composition are suspended therein; (e) terminating steps (c) and
(d) when the proppant particles coated with the hardenable resin
composition have been deposited in the one or more fractures; and;
(f) allowing the hardenable resin composition on the resin
composition coated proppant particles to harden by heat and
consolidate the proppant particles into one or more degradation
resistant permeable packs.
[0028] Another improved method of the present invention for forming
one or more fractures in a subterranean zone penetrated by a well
bore and consolidating proppant particles therein, the subterranean
zone having a temperature above about 225.degree. F. comprises the
steps of: (a) providing a liquid hardenable resin composition
comprised of a liquid bisphenol A-epichlorohydrin resin, a
4,4'-diaminodiphenyl sulfone hardening agent dissolved in a solvent
selected from the group consisting of dimethyl sulfoxide and
dimethyl formamide, an n-beta-(aminoethyl)-gamm-
a-aminopropyltrimethoxysilane coupling agent, a C.sub.12-C.sub.22
alkyl phosphate surfactant, a mixture of dimethyladipate and
dimethylsuccinate hydrolyzable esters and a dipropylene glycol
methyl ether diluent; (b) providing a source of dry proppant
particles; (c) providing a gelled liquid fracturing fluid comprised
of water and a gelling agent selected from the group consisting of
guar gum, guar gum derivatives and cellulose derivatives; (d)
pumping the gelled liquid fracturing fluid into the subterranean
zone to form the one or more fractures therein and to place the
proppant particles therein; (e) coating the hardenable resin
composition onto the dry proppant particles conveyed from the
source thereof to form hardenable resin composition coated proppant
particles; (f) mixing the hardenable resin composition coated
proppant particles formed in step (e) with the fracturing fluid
pumped in accordance with step (d) whereby the hardenable resin
composition coated proppant particles are suspended therein; (g)
terminating steps (d), (e) and (f) when the hardenable resin
composition coated proppant particles have been placed in the one
or more fractures; and (h) allowing the hardenable resin
composition on the hardenable resin composition coated proppant
particles to harden by heat and consolidate the proppant particles
into one or more degradation resistant permeable packs.
[0029] A hardenable resin composition of this invention for coating
proppant particles comprises: a hardenable resin comprised of a
liquid bisphenol A-epichlorohydrin resin; a 4,4'-diaminodiphenyl
sulfone hardening agent dissolved in a solvent selected from the
group consisting of dimethyl sulfoxide and dimethyl formamide; a
silane coupling agent; and a surfactant for facilitating the
coating of the resin on the proppant particles and for causing the
resin to flow to the contact points between adjacent resin coated
proppant particles.
[0030] In order to further illustrate the methods and compositions
of this invention, the following examples are given.
EXAMPLE 1
[0031] The effect of time and temperature on the viscosity of a
hardenable resin composition of this invention was determined. A
hardenable resin composition was prepared comprised of a liquid
bisphenol A-epichlorohydrin resin present in an amount of 49% by
weight of the composition, a 4,4'-diaminodiphenyl sulfone hardening
agent dissolved in a dimethyl sulfoxide solvent present in an
amount of about 35% by weight of the composition, an
n-beta-(aminoethyl)-gamma-aminopropyltrimethoxysil- ane coupling
agent present in an amount of about 1% by weight of the
composition, a C.sub.12-C.sub.22 alkyl phosphate surfactant present
in an amount of about 4% by weight of the composition and a mixture
of dimethylglutarate, dimethyladipate and dimethylsuccinate esters
present in an amount of about 1% by weight of the composition, and
a diluent of dipropylene glycol methyl ether in an amount of about
10% by weight of the composition.
[0032] Samples of the hardenable resin composition were exposed to
room temperature for eleven days and were maintained in a water
bath at a temperature of 120.degree. F. for eleven days. The
samples had viscosities between 1, 100 and 1300 centipoises which
is a desirable viscosity level for coating the resin onto proppant
particles.
EXAMPLE 2
[0033] One of the hardenable resin composition samples described in
Example 1 above was coated onto dry 20/40 mesh bauxite proppant
particles in an amount of 3% by weight of the proppant. The resin
coated proppant was mixed with water gelled with
carboxymethylhydroxypropyl guar and cross-linked with a zirconium
cross-linker. Two portions of the resulting viscous fluid
containing hardenable resin composition coated proppant particles
were stirred for 1 hour at 175.degree. F. to simulate the effect of
pumping and fluid suspension during a fracturing treatment. The
fluids were then transferred and packed into brass flow cells
without stress simulating fracture closure pressure. One of the
resulting proppant particle packs was cured at a temperature of
325.degree. F. for 3 hours and the other was cured at the same
temperature for 72 hours. Consolidated cores were obtained from the
proppant packs formed and the cores were tested for unconfined
compressive strengths.
[0034] The consolidated core that was cured for 3 hours had an
unconfined compressive strength of 1304.+-.108 psi and the
consolidated core that was cured for 72 hours had an unconfined
compressive strength of 1230.+-.47 psi.
[0035] Thus, the results of the tests described in Examples 1 and 2
above clearly show that the methods and hardenable resin
compositions of the present invention meet the needs described
above and overcome the deficiencies of the prior art.
[0036] Thus, the present invention is well adapted to attain the
objects and advantages mentioned as well as those which are
inherent therein. While numerous changes may be made by those
skilled in the art, such changes are encompassed within the spirit
of this invention as defined by the appended claims.
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