U.S. patent application number 12/745936 was filed with the patent office on 2010-11-04 for method of treating proppants and fractures in-situ with fluorinated silane.
Invention is credited to Jimmie R. Baran, JR., Wayne W. Fan, Madeline P. Shinbach, John D. Skildum.
Application Number | 20100276142 12/745936 |
Document ID | / |
Family ID | 40429802 |
Filed Date | 2010-11-04 |
United States Patent
Application |
20100276142 |
Kind Code |
A1 |
Skildum; John D. ; et
al. |
November 4, 2010 |
METHOD OF TREATING PROPPANTS AND FRACTURES IN-SITU WITH FLUORINATED
SILANE
Abstract
Method of treating proppant particles present in a fractured
subterranean geological formation comprising hydrocarbons in-situ
with fluorinated silane.
Inventors: |
Skildum; John D.; (North
Oaks, MN) ; Baran, JR.; Jimmie R.; (Prescott, WI)
; Fan; Wayne W.; (Cottage Grove, MN) ; Shinbach;
Madeline P.; (St. Paul, MN) |
Correspondence
Address: |
3M INNOVATIVE PROPERTIES COMPANY
PO BOX 33427
ST. PAUL
MN
55133-3427
US
|
Family ID: |
40429802 |
Appl. No.: |
12/745936 |
Filed: |
December 1, 2008 |
PCT Filed: |
December 1, 2008 |
PCT NO: |
PCT/US08/85116 |
371 Date: |
June 3, 2010 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60992442 |
Dec 5, 2007 |
|
|
|
Current U.S.
Class: |
166/280.2 ;
166/308.1 |
Current CPC
Class: |
C09K 8/68 20130101; C09K
8/80 20130101; C08G 18/2885 20130101; C08G 18/289 20130101 |
Class at
Publication: |
166/280.2 ;
166/308.1 |
International
Class: |
E21B 43/267 20060101
E21B043/267; E21B 43/26 20060101 E21B043/26 |
Claims
1. (canceled)
2. A method of treating proppant particles present in a fractured
subterranean geological formation comprising hydrocarbons, the
method comprising injecting fluorinated silane into the fracture to
treat the proppant particles in-situ, wherein the fluorinated
silane is selected from the group consisting of:
Rf{-Q-[SiY.sub.3-x(R).sub.x].sub.y}.sub.z; a polymeric fluorinated
composition comprising: at least one divalent unit represented by
the formula: ##STR00010## and at least one of at least one divalent
unit represented by the formula: ##STR00011## or a
chain-terminating group represented by the formula:
--S--W--SiY.sub.3-x(R).sub.x; and a fluorinated urethane oligomer
of at least two repeat units comprising: at least one end group
represented by the formula --O--Z--Rf.sup.2, and at least one end
group represented by the formula
--X.sup.1--W--SiY.sub.3-x(R).sub.x; wherein Rf is a monovalent or
multivalent perfluoropolyether group having two or more in-chain
oxygen atoms; Rf.sup.2 is a monovalent perfluoroalkyl group
optionally interrupted by at least one --O--; each R is
independently selected from the group consisting of alkyl having
one to six carbon atoms and aryl; Q is a divalent or trivalent
organic linking group; each Y is independently selected from the
group consisting of hydroxyl, alkoxy, acyloxy, and halogen; each
R.sup.1 is independently selected from the group consisting of
hydrogen and alkyl having one to four carbon atoms; each W is
independently selected from the group consisting of alkylene,
arylalkylene, and arylene, wherein alkylene is optionally
interrupted by or substituted by at least one heteroatom; each X is
independently selected from the group consisting of --NH--, --O--,
and --S--; X.sup.1 is selected from the group consisting of
--N(H)--, --N(CH.sub.3--, --N(C.sub.6H.sub.5)--, --S--, --O--,
--O--C(O)--NH--, and --O-alkylene-O--C(O)--NH--; Z is a divalent
organic linking group; x is 0, 1, or 2; y is 1 or 2; and z is 1, 2,
3, or 4.
3. The method according to claim 2, wherein the fluorinated silane
comprises at least one fluorinated urethane oligomer of at least
two repeat units comprising: at least one end group represented by
the formula --O--(CH.sub.2).sub.nN(R.sup.4)S(O).sub.2--Rf.sup.3,
and at least one end group represented by the formula
--NH--(CH.sub.2).sub.n--SiY.sub.3; wherein R.sup.4 is alkyl having
one to four carbon atoms; Rf.sup.3 is a perfluoroalkyl group having
from one to eight carbon atoms; each Y is independently selected
from the group consisting of hydroxyl, alkoxy, acyloxy, and
halogen; and each n is independently an integer from 1 to 4.
4. The method according to claim 2, wherein at least a portion of
the proppant particles are ceramic particles.
5. The method according to claim 2, wherein at least a portion of
the proppant particles are engineered particles.
6. The method according to claim 2, wherein at least a portion of
the proppant particles are at least 500 micrometers in size.
7. The method according to claim 2, wherein at least a portion of
the treated proppant particles have a plurality of pores, and
wherein at least a portion of the treated proppant particles have
at least one of water or oil imbibition up to 95% as compared to
comparable, untreated proppant particles.
8. A method of fracturing a subterranean geological formation
comprising hydrocarbons, the method comprising: injecting a
hydraulic fluid into a subterranean geological formation comprising
hydrocarbons at a rate and pressure sufficient to open a fracture
therein; injecting into the fracture a fracture fluid comprising a
plurality of proppant particles; and subsequent to the injection of
the hydraulic and fracture fluids, injecting fluorinated silane
into the fracture to treat the proppant particles in-situ, wherein
the fluorinated silane is selected from the group consisting of:
Rf{-Q-[SiY.sub.3-x(R).sub.x].sub.y}.sub.z; a polymeric fluorinated
composition comprising: at least one divalent unit represented by
the formula: ##STR00012## and at least one of at least one divalent
unit represented by the formula: ##STR00013## or a
chain-terminating group represented by the formula:
--S--W--SiY.sub.3-x(R).sub.x; and a fluorinated urethane oligomer
of at least two repeat units comprising: at least one end group
represented by the formula --O--Z--Rf.sup.2, and at least one end
group represented by the formula
--X.sup.1--W--SiY.sub.3-x(R).sub.x; wherein Rf is a monovalent or
multivalent perfluoropolyether group having two or more in-chain
oxygen atoms; Rf.sup.2 is a monovalent perfluoroalkyl group
optionally interrupted by at least one --O--; each R is
independently selected from the group consisting of alkyl having
one to six carbon atoms and aryl; Q is a divalent or trivalent
organic linking group; each Y is independently selected from the
group consisting of hydroxyl, alkoxy, acyloxy, and halogen; each
R.sup.1 is independently selected from the group consisting of
hydrogen and alkyl having one to four carbon atoms; each W is
independently selected from the group consisting of alkylene,
arylalkylene, and arylene, wherein alkylene is optionally
interrupted by or substituted by at least one heteroatom; each X is
independently selected from the group consisting of --NH--, --O--,
and --S--; X.sup.1 is selected from the group consisting of
--N(H)--, --N(CH.sub.3)--, --N(C.sub.6H.sub.5)--, --S--, --O--,
--O--C(O)--NH--, and --O-alkylene-O--C(O)--NH--; Z is a divalent
organic linking group; x is 0, 1, or 2; y is 1 or 2; and z is 1, 2,
3, or 4.
9. (canceled)
10. The method according to claim 8, wherein the fluorinated silane
comprises at least one fluorinated urethane oligomer of at least
two repeat units comprising: at least one end group represented by
the formula --O--(CH.sub.2).sub.nN(R.sup.4)S(O).sub.2--Rf.sup.3,
and at least one end group represented by the formula
--NH--(CH.sub.2).sub.n--SiY.sub.3; wherein R.sup.4 is alkyl having
one to four carbon atoms; Rf.sup.3 is a perfluoroalkyl group having
from one to eight carbon atoms; each Y is independently selected
from the group consisting of hydroxyl, alkoxy, acyloxy, and
halogen; and each n is independently an integer from 1 to 4.
11. The method according to claim 8, wherein at least a portion of
the proppant particles are ceramic particles.
12. The method according to claim 8, wherein at least a portion of
the proppant particles are engineered particles.
13. The method according to claim 8, wherein at least a portion of
the proppant particles are at least 500 micrometers in size.
14. The method according to claim 8, wherein at least a portion of
the treated proppant particles have a plurality of pores, and
wherein at least a portion of the treated proppant particles have
at least one of water or oil imbibition up to 95% as compared to
comparable, untreated proppant particles.
15. A method of fracturing a subterranean geological formation
comprising hydrocarbons, the method comprising: injecting a
hydraulic fluid into a subterranean geological formation comprising
hydrocarbons at a rate and pressure sufficient to open a fracture
therein; injecting fluorinated silane into the fracture to treat
the fracture in-situ, wherein the fluorinated silane is selected
from the group consisting of:
Rf{-Q-[SiY.sub.3-x(R).sub.x].sub.y}.sub.z; a polymeric fluorinated
composition comprising: at least one divalent unit represented by
the formula: ##STR00014## and at least one of at least one divalent
unit represented by the formula: ##STR00015## or a
chain-terminating group represented by the formula:
--S--W--SiY.sub.3-x(R).sub.x; and a fluorinated urethane oligomer
of at least two repeat units comprising: at least one end group
represented by the formula --O--Z--Rf.sup.2, and at least one end
group represented by the formula
--X.sup.1--W--SiY.sub.3-x(R).sub.x; wherein Rf is a monovalent or
multivalent perfluoroalkyl group optionally interrupted by at least
one --O--; Rf.sup.2 is a monovalent perfluoroalkyl group optionally
interrupted by at least one --O--; each R is independently selected
from the group consisting of alkyl having one to six carbon atoms
and aryl; Q is a divalent or trivalent organic linking group; each
Y is independently selected from the group consisting of hydroxyl,
alkoxy, acyloxy, and halogen; each R.sup.1 is independently
selected from the group consisting of hydrogen and alkyl having one
to four carbon atoms; each W is independently selected from the
group consisting of alkylene, arylalkylene, and arylene, wherein
alkylene is optionally interrupted by or substituted by at least
one heteroatom; each X is independently selected from the group
consisting of --NH--, --O--, and --S--; X.sup.1 is selected from
the group consisting of --N(H)--, --N(CH.sub.3--,
--N(C.sub.6H.sub.5)--, --S--, --O--, --O--C(O)--NH--, and
--O-alkylene-O--C(O)--NH--; Z is a divalent organic linking group;
x is 0, 1, or 2; y is 1 or 2; and z is 1, 2, 3, or 4, and after
injecting the fluorinated silane into the fracture, injecting a
fracture fluid comprising a plurality of proppant particles into
the fracture.
16. The method according to claim 15, wherein prior to injecting
the fluorinated silane into the fracture, the method further
comprises injecting a fracture fluid comprising a plurality of
proppant particles into the fracture.
17. (canceled)
18. The method according to claim 15, wherein at least some of the
proppants injected into the fracture are treated with the
fluorinated silane prior to their injection.
19. The method according to claim 15, wherein the fluorinated
silane comprises at least one fluorinated urethane oligomer of at
least two repeat units comprising: at least one end group
represented by the formula
--O--(CH.sub.2).sub.nN(R.sup.4)S(O).sub.2--Rf.sup.3, and at least
one end group represented by the formula
--NH--(CH.sub.2).sub.n--SiY.sub.3; wherein R.sup.4 is alkyl having
one to four carbon atoms; Rf.sup.3 is a perfluoroalkyl group having
from one to eight carbon atoms; each Y is independently selected
from the group consisting of hydroxyl, alkoxy, acyloxy, and
halogen; and each n is independently an integer from 1 to 4.
20. The method according to claim 15, wherein the fracture has a
conductivity improved by the presence of fluorinated siloxane which
is a condensation product of the fluorinated silane.
Description
BACKGROUND
[0001] Oil and natural gas can be produced from wells having porous
and permeable subterranean formations. The porosity of the
formation permits the formation to store oil and gas, and the
permeability of the formation permits the oil or gas fluid to move
through the formation. Permeability of the formation is essential
to permit oil and gas to flow to a location where it can be pumped
from the well. Sometimes the permeability of the formation holding
the gas or oil is insufficient for the desired recovery of oil and
gas. In other cases, during operation of the well, the permeability
of the formation drops to the extent that further recovery becomes
uneconomical. In such cases, it is common to fracture the formation
and prop the fracture in an open condition using a proppant
material or propping agent. Such fracturing is usually accomplished
by hydraulic pressure. The proppant material or propping agent is
typically a particulate material, such as sand and (man-made)
engineered proppants, such as resin coated sand and high-strength
ceramic materials (e.g., sintered bauxite, crystalline ceramic
bubbles, and ceramic (e.g., glass) beads), which are carried into
the fracture by a fluid.
[0002] Further, for example, if relatively light weight, porous
crystalline ceramic (e.g., alumina) proppants are used, fluid
(e.g., the fracturing fluid) can penetrate into the proppant
increasing its density, which can in turn can adversely affect the
flow of the proppant into the fractured areas.
[0003] There continues to be a need for additional proppant
options, preferably, proppants with improved properties. Also, for
example, there is a desire, particularly for relatively light
weight, porous proppants, to prevent, or at least reduce,
penetration of fluids into the proppants.
SUMMARY
[0004] In one aspect, the present disclosure provides a method of
treating proppant particles present in a fractured subterranean
geological formation comprising hydrocarbons, the method comprising
injecting fluorinated silane into the fracture to treat the
proppant particles in-situ. In some embodiments, the resulting
fluorinated siloxane is bonded to the treated particle.
[0005] In another aspect, the present disclosure provides a method
of fracturing a subterranean geological formation comprising
hydrocarbons, the method comprising:
[0006] injecting a hydraulic fluid into a subterranean geological
formation comprising hydrocarbons at a rate and pressure sufficient
to open a fracture therein;
[0007] injecting into a fracture fluid comprising a plurality of
proppant particles; and
[0008] subsequent to the injection of the hydraulic and fracture
fluids, injecting fluorinated silane into the fracture to treat the
proppant particles in-situ.
[0009] In another aspect, the present disclosure provides a method
of fracturing a subterranean geological formation comprising
hydrocarbons, the method comprising:
[0010] injecting a hydraulic fluid into a subterranean geological
formation comprising hydrocarbons at a rate and pressure sufficient
to open a fracture therein; and
[0011] injecting fluorinated silane into the fracture to treat the
fracture in-situ. In some embodiments, and typically, prior to
injecting the fluorinated silane into the fracture, the method
further comprises injecting into a fracture fluid comprising a
plurality of proppant particles into the fracture. In some
embodiments, subsequent to injecting the fluorinated silane into
the fracture, the method further comprises injecting into a
fracture fluid comprising a plurality of proppant particles into
the fracture. In some embodiments, at least some of the proppant
injected into the fracture is treated with the fluorinated silane
prior to their injection.
[0012] In some embodiments, the fluorinated silane comprises a
reactive fluorinated silane selected from the group consisting
of:
Rf{-Q-[SiY.sub.3-x(R).sub.x].sub.y}.sub.z;
[0013] a polymeric fluorinated composition comprising: [0014] at
least one divalent unit represented by the formula:
[0014] ##STR00001## and [0015] at least one of [0016] at least one
divalent unit represented by the formula:
[0016] ##STR00002## or [0017] a chain-terminating group represented
by the formula:
[0017] --S--W--SiY.sub.3-x(R).sub.x; and
[0018] a fluorinated urethane oligomer of at least two repeat units
comprising: [0019] at least one end group represented by the
formula --O--Z--Rf.sup.2, and [0020] at least one end group
represented by the formula --X.sup.1--W--SiY.sub.3-x(R).sub.x;
wherein
[0021] Rf is a monovalent or multivalent perfluoroalkyl group
optionally interrupted by at least one --O--;
[0022] Rf.sup.2 is a monovalent perfluoroalkyl group optionally
interrupted by at least one --O--;
[0023] each R is independently selected from the group consisting
of alkyl having one to six carbon atoms and aryl;
[0024] Q is a divalent or trivalent organic linking group;
[0025] each Y is independently selected from the group consisting
of hydroxyl, alkoxy, acyloxy, and halogen;
[0026] each R.sup.1 is independently selected from the group
consisting of hydrogen and alkyl having one to four carbon
atoms;
[0027] each W is independently selected from the group consisting
of alkylene, arylalkylene, and arylene, wherein alkylene is
optionally interrupted or substituted by at least one
heteroatom;
[0028] each X is independently selected from the group consisting
of --NH--, --O--, and --S--;
[0029] X.sup.1 is selected from the group consisting of
--N(R.sup.3)--, --S--, --O--, --O--C(O)--NH--, and
--O-alkylene-O--C(O)--NH--;
[0030] Z is a divalent organic linking group;
[0031] x is 0, 1, or 2;
[0032] y is 1 or 2; and
[0033] z is 1, 2, 3, or 4.
[0034] In some embodiments, the fluorinated silane comprises at
least one fluorinated urethane oligomer of at least two repeat
units comprising: [0035] at least one end group represented by the
formula
[0035] --O--(CH.sub.2).sub.nN(R.sup.4)S(O).sub.2--Rf.sup.3, and
[0036] at least one end group represented by the formula
[0036] --NH--(CH.sub.2).sub.n--SiY.sub.3;
wherein
[0037] R.sup.4 is alkyl having one to four carbon atoms
[0038] Rf.sup.3 is a perfluoroalkyl group having from one to eight
carbon atoms;
[0039] each Y is independently selected from the group consisting
of hydroxyl, alkoxy, acyloxy, and halogen; and
[0040] each n is independently an integer from 1 to 4.
[0041] In some embodiments, the fracture has a conductivity
improved by the presence of the (resulting) fluorinated siloxane.
The conductivity of a fracture is a measure of the effectiveness of
a hydraulically treated fracture or essentially how well the
fracture improves the flow of oil or gas from the formation. The
conductivity of a fracture can be determined using API Conductivity
Test RP 61, entitled "Recommended Practices for Evaluating Short
Term Proppant Pack Conductivity" (October, 1989).
[0042] Treated proppants and/or fractures described herein are
useful, for example, in facilitating the removal of fracturing
fluids that have been injected into subterranean formation,
including increasing the removal rate of the fracturing fluid.
While not wanting to be bound by theory, it is believed this
enhanced back-production of the fracturing fluids is due to the
fluorinated siloxane altering the wettability of the proppant
and/or fracture, thus rendering the proppant and/or fracture
hydrophobic, oleophobic, and non-wetted by the fracturing fluids.
An additional advantage of enhancing the fluid production from the
fracture comprising the proppant and/or fracture treated with the
fluorinated silane is thought to be the reduction in turbulent flow
that should significantly reduce non-Darcy effects. Non-Darcy
effects can effectively reduce the conductivity of a fracture by
reducing fluid production. Advantages of embodiments of treated
particles having a plurality of pores is that the treated particle
has at least one of water or oil imbibition up to 95% as compared
to a comparable, untreated particle.
DETAILED DESCRIPTION
[0043] Exemplary proppants for practicing the methods described
herein include those known in the art for use in fractured
subterranean geological formations comprising hydrocarbons,
including engineered proppants (e.g., resin coated sand, sintered
bauxite, crystalline ceramic bubbles, and ceramic (e.g., glass)
beads), as well as sand graded to desired industry standards). The
term "ceramic" as used herein refers to glasses, crystalline
ceramics, glass-ceramics, and combinations thereof. Suitable
proppant can be made by techniques known in the art and/or obtained
from commercial sources. Exemplary proppants include those made of
a material selected from the group consisting of sand,
thermoplastic, clay, glass, and alumina (e.g., sintered bauxite).
Examples of proppants include sand, clay-based particles,
thermoplastic particles, and sintered bauxite particles. Sand
proppants are available, for example, from Badger Mining Corp.,
Berlin, Wis.; Borden Chemical, Columbus, Ohio; Fairmont Minerals,
Chardon, Ohio. Thermoplastic proppants are available, for example,
from the Dow Chemical Company, Midland, Mich.; and BJ Services,
Houston, Tex. Clay-based proppants are available, for example, from
CarboCeramics, Irving, Tex.; and Saint-Gobain, Courbevoie, France.
Sintered bauxite ceramic proppants are available, for example, from
Borovichi Refractories, Borovichi, Russia; 3M Company, St. Paul,
Minn.; CarboCeramics, and Saint Gobain. Engineered proppants such
as glass bead and ceramic microsphere proppants are available, for
example, from Diversified Industries, Sidney, British Columbia,
Canada; and 3M Company.
[0044] In some embodiments, the proppant is at least 100
micrometers (in some embodiments, at least 200, 300, 400, 500, 600,
700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700,
1800, 1900, 2000, 2500, or even at least 3000 micrometers; in some
embodiments, in a range from 500 micrometers to 1700 micrometers)
in size. In some embodiments, the proppant have particle sizes in a
range from 100 micrometers to 3000 micrometers (i.e., about 140
mesh to about 5 mesh) (in some embodiments, in a range from 1000
micrometers to 3000 micrometers, 1000 micrometers to 2000
micrometers, 1000 micrometers to 1700 micrometers (i.e., about 18
mesh to about 12 mesh), 850 micrometers to 1700 micrometers (i.e.,
about 20 mesh to about 12 mesh), 850 micrometers to 1200
micrometers (i.e., about 20 mesh to about 16 mesh), 600 micrometers
to 1200 micrometers (i.e., about 30 mesh to about 16 mesh), 425
micrometers to 850 micrometers (i.e., about 40 to about 20 mesh),
300 micrometers to 600 micrometers (i.e., about 50 mesh to about 30
mesh), 250 micrometers to 425 micrometers (i.e., about 60 mesh to
about 40 mesh), 200 micrometers to 425 micrometers (i.e., about 70
mesh to about 40 mesh), or 100 micrometers to 200 micrometers
(i.e., about 140 mesh to about 70 mesh).
[0045] In some embodiments, the proppants (e.g., ceramic particles)
have a plurality of pores. The pores can be closed or open with
respect to each other, or a mixture of opened and closed porosity.
In some embodiments, the proppants (e.g., ceramic particles) have a
density of at least 2 g/cm.sup.3 (in some embodiments, at least 2.5
g/cm.sup.3, at least 3 g/cm.sup.3; in some embodiments, in a range
from 2 g/cm.sup.3 to 3 g/cm.sup.3).
[0046] In some embodiments, the fluorinated silane comprises a
reactive fluorinated silane represented by the formula (I):
Rf{-Q-[SiY.sub.3-x(R).sub.x].sub.y}.sub.z I, [0047] wherein Rf, Q,
Y, R, x, y, and z are as defined above. Rf is a monovalent or
multivalent perfluoroalkyl group optionally interrupted by at least
one --O--. Rf can be a linear, branched, and/or cyclic structure,
that may be saturated or unsaturated. The term "perfluoroalkyl
group" includes groups in which all C--H bonds are replaced by C--F
bonds as well as groups in which hydrogen or chlorine atoms are
present instead of fluorine atoms provided that not more than one
atom of either hydrogen or chlorine is present for every two carbon
atoms. In some embodiments, when hydrogen and/or chlorine are
present, Rf includes at least one trifluoromethyl group.
[0048] In some embodiments, Rf is a monovalent perfluoroalkyl group
of formula (C.sub.nF.sub.2n+1), wherein n is an integer from 1 to
20 (in some embodiments, from 3 to 12 or even from 3 to 8). In some
embodiments, Rf is C.sub.4F.sub.9.
[0049] In some embodiments, Rf is a perfluoropolyether group having
two or more in-chain oxygen atoms. In some embodiments, the
perfluoropolyether group comprises perfluorinated repeating units
selected from the group consisting of --(C.sub.nF.sub.2n)--,
--(C.sub.nF.sub.2nO)--, --(CF(Rf.sup.4))--, --(CF(Rf.sup.4)O)--,
--(CF(Rf.sup.4)C.sub.nF.sub.2nO)--,
--(C.sub.nF.sub.2nCF(Rf.sup.4)O)--, --(CF.sub.2CF(Rf.sup.4)O)--,
and combinations thereof (in some embodiments,
--(C.sub.nF.sub.2nO)--, --(CF(Rf.sup.4)O)--,
--(CF(Rf.sup.4)C.sub.nF.sub.2nO)--,
--(C.sub.nF.sub.2nCF(Rf.sup.4)O)--, --(CF.sub.2CF(Rf.sup.4)O)--,
and combinations thereof); wherein Rf.sup.4 is a perfluoroalkyl
group, a perfluoroalkoxy group, or a perfluoroether group, each of
which can be linear, branched, or cyclic, and can have 1 to 9
carbon atoms and up to 4 oxygen atoms; and n is an integer from 1
to 12 (in some embodiments, from 1 to 6, from 1 to 4, or even from
1 to 3). The perfluorinated repeating units may be arranged
randomly, in blocks, or in alternating sequence.
[0050] In some embodiments, Rf is a monovalent (i.e., z is 1)
perfluoropolyether group. In some of these embodiments, Rf is
terminated with C.sub.nF.sub.2n+1--, C.sub.nF.sub.2n+1O--, or
X'C.sub.nF.sub.2nO--, wherein X' is a hydrogen or chlorine atom. In
some of these embodiments, the terminal group is
C.sub.nF.sub.2n+1-- or C.sub.nF.sub.2n+1O--, wherein n is an
integer from 1 to 6 or from 1 to 3. In some of these embodiments,
the approximate average structure of Rf is
C.sub.3F.sub.7O(CF(CF.sub.3)CF.sub.2O).sub.pCF(CF.sub.3)-- or
CF.sub.3O(C.sub.2F.sub.4O).sub.pCF.sub.2--, wherein the average
value of p is 3 to 50.
[0051] In some embodiments, Rf is a divalent (i.e., z is 2)
perfluoropolyether group. In some of these embodiments, Rf is
selected from the group consisting of
--CF.sub.2O(CF.sub.2O).sub.m(C.sub.2F.sub.4O).sub.pCF.sub.2--,
--CF(CF.sub.3)--(OCF.sub.2CF(CF.sub.3)).sub.pO--Rf.sup.5--O(CF(CF.sub.3)C-
F.sub.2O).sub.pCF(CF.sub.3)--,
--CF.sub.2O(C.sub.2F.sub.4O).sub.pCF.sub.2--, and
--(CF.sub.2).sub.3O(C.sub.4F.sub.8O).sub.p(CF.sub.2).sub.3--,
wherein Rf.sup.5 is a divalent, perfluoroalkylene group containing
at least one carbon atom and optionally interrupted in chain by O
or N; m is 1 to 50; and p is 3 to 40. In some embodiments, Rf.sup.5
is (C.sub.nF.sub.2n), wherein n is 2 to 4. In some embodiments, Rf
is selected from the group consisting of
--CF.sub.2O(CF.sub.2O).sub.m(C.sub.2F.sub.4O).sub.pCF.sub.2--,
--CF.sub.2O(C.sub.2F.sub.4O).sub.pCF.sub.2--, and
CF(CF.sub.3)--(OCF.sub.2CF(CF.sub.3)).sub.pO--(C.sub.nF.sub.2n)--O(CF(CF.-
sub.3)CF.sub.2O).sub.pCF(CF.sub.3)--, wherein n is 2 to 4, and the
average value of m+p or p or p+p, respectively, is from about 4 to
about 24. In some embodiments, p and m may be non-integral.
[0052] The divalent or trivalent organic linking group, Q, can be a
linear, branched, or cyclic structure, that may be saturated or
unsaturated and optionally contains one or more heteroatoms
selected from the group consisting of sulfur, oxygen, and nitrogen,
and/or optionally contains one or more functional groups selected
from the group consisting of ester, amide, sulfonamide, carbonyl,
carbonate, urea, and carbamate. Q includes at least 2 carbon atoms
and not more than about 25 carbon atoms (in some embodiments, not
more than 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11,
or even not more than 10 carbon atoms). When two, three, or four Q
groups are present, each Q is independently selected. In some
embodiments, Q is a linear hydrocarbon containing 1 to about 10
carbon atoms, optionally containing 1 to 4 heteroatoms and/or 1 to
4 functional groups. In some of these embodiments, Q contains one
functional group.
[0053] Exemplary divalent Q groups include
--SO.sub.2NR.sup.2(CH.sub.2).sub.kO(O)C--,
--CON(R.sup.2)(CH.sub.2).sub.kO(O)C--, --(CH.sub.2).sub.kO(O)C--,
--C(O)N(R.sup.2)--(CH.sub.2).sub.k--,
--CH.sub.2CH(O-alkyl)CH.sub.2O(O)C--,
--(CH.sub.2).sub.kC(O)O(CH.sub.2).sub.k--,
--(CH.sub.2).sub.kSC(O)--,
--(CH.sub.2).sub.kO(CH.sub.2).sub.kO(O)C--,
--(CH.sub.2).sub.kS(CH.sub.2).sub.kO(O)C--,
--(CH.sub.2).sub.kSO.sub.2(CH.sub.2).sub.kO(O)C--,
--(CH.sub.2).sub.kS(CH.sub.2).sub.kOC(O)--,
--(CH.sub.2).sub.kSO.sub.2N(R.sup.2)(CH.sub.2).sub.kO(O)C--,
--(CH.sub.2).sub.kSO.sub.2--,
--SO.sub.2N(R.sup.2)(CH.sub.2).sub.kO(CH.sub.2).sub.k--,
--SO.sub.2N(R.sup.2)(CH.sub.2).sub.k--,
--(CH.sub.2).sub.kO(CH.sub.2).sub.kC(O)O(CH.sub.2).sub.k--,
--(CH.sub.2).sub.kSO.sub.2N(R.sup.2)(CH.sub.2).sub.kC(O)O(CH.sub.2).sub.k-
--,
--(CH.sub.2).sub.kSO.sub.2(CH.sub.2).sub.kC(O)O(CH.sub.2).sub.k--,
--CON(R.sup.2)(CH.sub.2).sub.kC(O)O(CH.sub.2).sub.k--,
--(CH.sub.2).sub.kS(CH.sub.2).sub.kC(O)O(CH.sub.2).sub.k--,
--CH.sub.2CH(O-alkyl)CH.sub.2C(O)O(CH.sub.2).sub.k--,
--SO.sub.2N(R.sup.2)(CH.sub.2).sub.kC(O)O(CH.sub.2).sub.k--,
--(CH.sub.2).sub.kO(CH.sub.2).sub.k--,
--CH.sub.2O--(CH.sub.2).sub.k--,
--OC(O)N(R.sup.2)(CH.sub.2).sub.k--,
--(CH.sub.2).sub.kN(R.sup.2)--, --C.sub.kH.sub.2k--OC(O)NH--,
--(CH.sub.2).sub.kN(R.sup.2)C(O)O(CH.sub.2).sub.k--,
--(CH.sub.2).sub.k--, --C.sub.kH.sub.2k--,
--C(O)S--(CH.sub.2).sub.k--, and
--CH.sub.2OC(O)N(R.sup.2)--(CH.sub.2).sub.k--, wherein R.sup.2 is
hydrogen, C.sub.1-4 alkyl, or phenyl; and k is 2 to about 25 (in
some embodiments, 2 to 15 or even 2 to 10).
[0054] Exemplary trivalent Q groups include
##STR00003##
wherein R.sup.2 is hydrogen, [0055] C.sub.1-4 alkyl, or phenyl;
each n and m are independently integers from 1 to 20 (in some
embodiments, from 1 to 6 or even from 1 to 4); m' is an integer
from 1 to 20 (in some embodiments, from 1 to 10 or even from 1 to
3); Q.sup.2 is selected from the group consisting of
--C(O)NH--(CH.sub.2).sub.n'-- and --(CH.sub.2).sub.n'--, wherein n'
is an integer from 0 to 4; and X is selected from the group
consisting of --NH--, --O--, and --S--.
[0056] Each Y in Formula I is selected from the group consisting of
hydroxyl, alkoxy (e.g., of 1 to 4 or even 1 to 2 carbon atoms),
aryloxy (e.g., phenoxy), acyloxy (e.g., of 1 to 4 or even 1 to 2
carbon atoms), polyalkyleneoxy, and halogen (e.g., Cl or Br).
"Polyalkyleneoxy" refers to
--O--(CHR.sup.5--CH.sub.2O).sub.q--R.sup.3 wherein R.sup.3 is
C.sub.1-4 alkyl, R.sup.5 is hydrogen or methyl, with at least 70%
of R.sup.5 being hydrogen, and q is 1 to 40, or even 2 to 10. In
some embodiments, each Y is independently a hydrolyzable group
selected from the group consisting of alkoxy (e.g., of 1 to 4 or
even 1 to 2 carbon atoms), aryloxy (e.g., phenoxy), and halogen
(e.g., Cl or Br). These hydrolysable groups are capable of
hydrolyzing, for example, in the presence of water, optionally
under acidic or basic conditions, producing groups capable of
undergoing a condensation reaction, for example silanol groups. In
some embodiments, R is alkyl of one to six carbon atoms (e.g.,
methyl, ethyl, propyl, isopropyl, butyl, isobutyl). In some
embodiments, R is aryl (e.g., phenyl). In some embodiments, x is 0.
In some embodiments, x is 1.
[0057] Some reactive fluorinated silanes of formula I are
commercially available, for example, a fluorinated silane
(available, for example, from Daikin Industries, Inc., New York,
N.Y. under the trade designation "OPTOOL DSX") and
tridecafluorooctyl functional silanes (available, for example, from
United Chemical Technologies, Inc., Bristol, Pa. under the trade
designation "PETRARCH" (e.g., grades "T2492" and "T2494").
[0058] The compounds of formula I described above can be
synthesized using conventional synthetic methods. For example, when
Rf is a perfluoropolyether group, perfluoropolyether esters or
functional derivatives thereof can be combined with a
functionalized alkoxysilane, such as a 3-aminopropylalkoxysilane,
according to the method described in U.S. Pat. No. 3,810,874
(Mitsch et al.). It will be understood that functional groups other
than esters may be used with equal facility to incorporate silane
groups into a perfluoropolyether. Some perfluoropolyether diesters
are commercially available (e.g.,
CH.sub.3OC(O)CF.sub.2(OCF.sub.2CF.sub.2).sub.9-10(OCF.sub.2).sub.9-10CF.s-
ub.2C(O)OCH.sub.3, a perfluoropolyether diester available, for
example, from Solvay Solexis, Houston, Tex., under the trade
designation "FOMBLIN ZDEAL"). Other perfluoropolyether diesters may
be prepared, for example, through direct fluorination of a
hydrocarbon polyether diester by methods known in the art (see,
e.g., U.S. Pat. Nos. 5,578,278 (Fall et al.) and 5,658,962 (Moore
et al.). Perfluoropolyether diesters (and perfluoropolyether
monoesters) can also be prepared, for example, by oligomerization
of hexafluoropropylene oxide (HFPO) and functionalization of the
resulting perfluoropolyether carbonyl fluoride according to the
methods described in U.S. Pat. No. 4,647,413 (Savu). An exemplary
fluorinated silane of formula I wherein Rf is a divalent
perfluoropolyether group is
(CH.sub.3O).sub.3Si(CH.sub.2).sub.3NHCOCF.sub.2(OCF.sub.2CF.sub.2).sub.9--
10(OCF.sub.2).sub.9-10CF.sub.2CONH(CH.sub.2).sub.3Si(OCH.sub.3).sub.3.
[0059] The above-described polyfluoropolyether silanes typically
include a distribution of oligomers and/or polymers, and above
structures are approximate average structures where the approximate
average is over this distribution. These distributions may also
contain perfluoropolyethers with no silane groups or more than two
silane groups. Typically, distributions containing less than about
10% by weight of compounds without silane groups can be used.
[0060] Methods of making fluorinated silanes of the formula I,
wherein Rf is a monovalent perfluoroalkyl group, are known in the
art (e.g., by alkylation of fluorinated alcohols or sulfonamides
with chloroalkyltrialkoxysilanes, or alkylation with allyl chloride
followed by hydrosilation with HSiCl.sub.3) (see, e.g., U.S. Pat.
No. 5,274,159 (Pellerite et al.). Fluorinated silanes represented
by the formulas
##STR00004##
wherein each Rf is independently C.sub.pF.sub.2p+1, wherein p is 1
to 8 and R.sup.2, R, m, n, m', n', X, and Q.sup.2 are as defined
above, can be prepared, for example, by similar methods (e.g., by
alkylation of
Rf--S(O).sub.2--N(R.sup.2)--(C.sub.n+mH.sub.2(n+m))--NH(S(O).sub.2--Rf
or
Rf--S(O).sub.2--N(R.sup.2)--(C.sub.nH.sub.2n)--CH(OH)--(C.sub.mH.sub.2m)--
-N(R.sup.2)--S(O).sub.2--Rf), respectively, with
chloroalkyltrialkoxysilanes) or by reaction of
Rf--S(O).sub.2--N(R.sup.2)--(C.sub.nH.sub.2n)--CH(OH)--(C.sub.mH.sub.2m)--
-N(R.sup.2)--S(O).sub.2--Rf with isocyanatoalkyltrialkoxysilanes as
described in U.S. Pat. App. Pub. No. 2006/0147645 (Dams et
al.).
[0061] Perfluoroalkyl silanes of formula I, wherein Rf is a
monovalent perfluoroalkyl group, include, for example, any one or
any combination of the following:
C.sub.3F.sub.7CH.sub.2OCH.sub.2CH.sub.2CH.sub.2Si(OCH.sub.3).sub.3;
C.sub.7F.sub.15CH.sub.2OCH.sub.2CH.sub.2CH.sub.2Si(OCH.sub.3).sub.3;
C.sub.7F.sub.15CH.sub.2OCH.sub.2CH.sub.2CH.sub.2Si(OCH.sub.2CH.sub.3).sub-
.3;
C.sub.7F.sub.15CH.sub.2OCH.sub.2CH.sub.2CH.sub.2Si(CH.sub.3)(OCH.sub.3-
).sub.2;
C.sub.7F.sub.15CH.sub.2OCH.sub.2CH.sub.2CH.sub.2SiCl.sub.3;
C.sub.7F.sub.15CH.sub.2OCH.sub.2CH.sub.2CH.sub.2Si(CH.sub.3)Cl.sub.2;
C.sub.7F.sub.15CH.sub.2OCH.sub.2CH.sub.2CH.sub.2SiCl(OCH.sub.3).sub.2;
C.sub.7F.sub.15CH.sub.2OCH.sub.2CH.sub.2CH.sub.2SiCl.sub.2(OC.sub.2H.sub.-
3);
C.sub.7F.sub.15C(O)NHCH.sub.2CH.sub.2CH.sub.2Si(OCH.sub.3).sub.3;
CF.sub.3(CF.sub.2CF(CF.sub.3)).sub.3CF.sub.2C(O)NHCH.sub.2CH.sub.2CH.sub.-
2Si(OCH.sub.2CH.sub.3).sub.3;
C.sub.8F.sub.17SO.sub.2N(CH.sub.2CH.sub.3)CH.sub.2CH.sub.2CH.sub.2Si(OCH.-
sub.3).sub.3;
C.sub.8F.sub.17SO.sub.2N(CH.sub.2CH.sub.3)CH.sub.2CH.sub.2CH.sub.2Si(OCH.-
sub.2CH.sub.3).sub.3;
C.sub.4F.sub.9SO.sub.2N(CH.sub.3)CH.sub.2CH.sub.2CH.sub.2Si(OCH.sub.3).su-
b.3;
C.sub.4F.sub.9SO.sub.2N(CH.sub.3)CH.sub.2CH.sub.2CH.sub.2Si(OCH.sub.2-
CH.sub.3).sub.3;
C.sub.8F.sub.17CH.sub.2CH.sub.2Si(OCH.sub.3).sub.3;
C.sub.6F.sub.13CH.sub.2CH.sub.2Si(OCH.sub.2CH.sub.3).sub.3;
C.sub.6F.sub.13CH.sub.2CH.sub.2Si(Cl).sub.3;
C.sub.8F.sub.17CH.sub.2CH.sub.2Si(OCH.sub.2CH.sub.3).sub.3;
C.sub.8F.sub.17SO.sub.2N(CH.sub.2CH.sub.3)CH.sub.2CH.sub.2CH.sub.2SiCl.su-
b.3;
C.sub.8F.sub.17SO.sub.2N(CH.sub.3)CH.sub.2CH.sub.2CH.sub.2Si(CH.sub.3-
)Cl.sub.2;
C.sub.8F.sub.17CH.sub.2OCH.sub.2CH.sub.2CH.sub.2Si(OAc).sub.3;
[C.sub.4F.sub.9S(O).sub.2N(CH.sub.3)CH.sub.2].sub.2CHOCH.sub.2CH.sub.2CH.-
sub.2Si(OCH.sub.3).sub.3;
[C.sub.4F.sub.9S(O).sub.2N(CH.sub.3)CH.sub.2].sub.2CHOC(O)NHCH.sub.2CH.su-
b.2CH.sub.2Si(OCH.sub.3).sub.3, and
C.sub.4F.sub.9S(O).sub.2N(CH.sub.3)CH.sub.2CH.sub.2CH.sub.2N(S(O).sub.2C.-
sub.4F.sub.9)CH.sub.2CH.sub.2CH.sub.2Si(OCH.sub.3).sub.3. Suitable
fluorinated silanes of formula I include a mixture of isomers
(e.g., a mixture of compounds containing linear and branched
perfluoroalkyl groups).
[0062] In some embodiments, useful fluorinated siloxanes comprise a
condensation product of a polymeric fluorinated composition
comprising: [0063] at least one divalent unit represented by the
formula (II):
[0063] ##STR00005## and [0064] at least one of [0065] at least one
divalent unit represented by the formula (III):
[0065] ##STR00006## or [0066] a chain-terminating group represented
by the formula (IV):
[0066] --S--W--SiY.sub.3-x(R).sub.x IV,
wherein, Rf.sup.2, R.sup.1, R, W, X, Y, Z, and x are as defined
above.
[0067] The term "polymeric" refers to both oligomers and polymers.
In some embodiments, the number of units represented by formula II
is in a range from 1 to 100 (in some embodiments from 1 to 20). In
some embodiments, the units represented by formula II are present
in a range from 40% by weight to 80% by weight (or even from 50% to
75% by weight) based on the total weight of the polymeric
fluorinated composition. In some embodiments, the number of units
represented by formula III is in a range from 0 to 100 (or even
from 0 to 20). In some embodiments, the units represented by
formula III are present in a range from 1% to 20% by weight (or
even 2% to 15% by weight) based on the total weight of the
polymeric fluorinated composition. In some embodiments, the
polymeric fluorinated composition contains at least 5 mole % (based
on total moles of monomers) of Y groups. In some embodiments, the
polymeric fluorinated composition has a number average molecular
weight in a range from 400 to 100000, from 3500 to 100000, or even
from 10000 to 75000 grams per mole or in a range from 600 to 20000,
or even from 1000 to 10000 grams per mole. It will be appreciated
by one skilled in the art that useful polymeric fluorinated
compositions exist as a mixture of compounds.
[0068] A divalent unit of formula II is typically introduced into a
polymeric fluorinated composition by polymerizing a monomer of the
formula (IIa):
##STR00007##
[0069] Fluorochemical monomers of formula IIa and methods for the
preparation thereof are known in the art (see, e.g., U.S. Pat. No.
2,803,615 (Ahlbrecht et al.). Examples of such compounds include,
for example, acrylates or methacrylates derived from fluorochemical
telomer alcohols, acrylates or methacrylates derived from
fluorochemical carboxylic acids, perfluoroalkyl acrylates or
methacrylates as disclosed in U.S. Pat. No. 5,852,148 (Behr et
al.), perfluoropolyether acrylates or methacrylates as described in
U.S. Pat. No. 4,085,137 (Mitsch et al.), and fluorinated
acrylamides, methacrylamides, thioacrylates, and meththioacrylates
as described in U.S. Pat. No. 6,689,854 (Fan et al.).
[0070] In some embodiments of formulas II and IIa, Rf.sup.2 is a
monovalent perfluoroalkyl group described above for Rf in
embodiments of a compound of formula I.
[0071] The divalent organic linking group, Z, can be a linear,
branched, or cyclic structure, that may be saturated or unsaturated
and optionally contains one or more heteroatoms selected from the
group consisting of sulfur, oxygen, and nitrogen, and/or optionally
contains one or more functional groups selected from the group
consisting of ester, amide, sulfonamide, carbonyl, carbonate,
ureylene, and carbamate. Z includes at least 1 carbon atom and not
more than about 25 carbon atoms (in some embodiments, not more than
24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, or even not
more than 10 carbon atoms). In some embodiments of formulas II and
IIa, Z is a divalent organic linking group as described above for
divalent Q groups. In some embodiments of formulas II and IIa, Z is
--C.sub.yH.sub.2y--, --CON(R.sup.1)C.sub.yH.sub.2y--,
--SO.sub.2N(R.sup.1)C.sub.yH.sub.2y--, or
C.sub.yH.sub.2ySO.sub.2N(R.sup.1)C.sub.yH.sub.2y--, wherein R.sup.1
is hydrogen, or alkyl of one to four carbon atoms, and y is
independently an integer from 1 to 6 (in some embodiments from 2 to
4). In some embodiments, R.sup.1 is hydrogen. In some embodiments,
R.sup.1 is alkyl of one to four carbon atoms.
[0072] Examples of fluorinated monomers of formula IIa include:
C.sub.4F.sub.9SO.sub.2N(CH.sub.3)C.sub.2H.sub.4OC(O)CH.dbd.CH.sub.2;
C.sub.5F.sub.11SO.sub.2N(C.sub.2H.sub.5)C.sub.2H.sub.4OC(O)CH.dbd.CH.sub.-
2;
C.sub.6F.sub.13SO.sub.2N(C.sub.2H.sub.5)C.sub.2H.sub.4OC(O)C(CH.sub.3).-
dbd.CH.sub.2;
C.sub.3F.sub.7SO.sub.2N(C.sub.4H.sub.9)C.sub.2H.sub.4OC(O)CH.dbd.CH.sub.2-
; C.sub.4F.sub.9CH.sub.2CH.sub.2OC(O)CH.dbd.CH.sub.2;
C.sub.5F.sub.11CH.sub.2OC(O)CH.dbd.CH.sub.2;
C.sub.6F.sub.13CH.sub.2CH.sub.2OC(O)CH.dbd.CH.sub.2;
CF.sub.3(CF.sub.2).sub.2CH.sub.2OC(O)CH.dbd.CH.sub.2,
CF.sub.3(CF.sub.2).sub.2CH.sub.2OC(O)C(CH.sub.3).dbd.CH.sub.2,
CF.sub.3(CF.sub.2).sub.3CH.sub.2OC(O)C(CH.sub.3).dbd.CH.sub.2,
CF.sub.3(CF.sub.2).sub.3CH.sub.2OC(O)CH.dbd.CH.sub.2,
CF.sub.3(CF.sub.2).sub.3S(O).sub.2N(R.sup.a)--(CH.sub.2).sub.2--OC(O)CH.d-
bd.CH.sub.2,
CF.sub.3(CF.sub.2).sub.3S(O).sub.2N(R.sup.a)--(CH.sub.2).sub.2--OC(O)C(CH-
.sub.3).dbd.CH.sub.2,
CF.sub.3CF.sub.2(CF.sub.2CF.sub.2).sub.2-8(CH.sub.2).sub.2OC(O)CH.dbd.CH.-
sub.2,
CF.sub.3(CF.sub.2).sub.7(CH.sub.2).sub.2OC(O)C(CH.sub.3).dbd.CH.sub-
.2,
CF.sub.3(CF.sub.2).sub.7S(O).sub.2N(R.sup.a)--(CH.sub.2).sub.2--OC(O)C-
H.dbd.CH.sub.2,
CF.sub.3(CF.sub.2).sub.7S(O).sub.2N(R.sup.a)--(CH.sub.2).sub.2--OC(O)C(CH-
.sub.3).dbd.CH.sub.2,
CF.sub.3(CF.sub.2).sub.7CH.sub.2CH.sub.2S(O).sub.2N(CH.sub.3)--(CH.sub.2)-
.sub.2--OC(O)C(CH.sub.3).dbd.CH.sub.2,
CF.sub.3O(CF.sub.2CF.sub.2).sub.uCH.sub.2OC(O)CH.dbd.CH.sub.2,
CF.sub.3O(CF.sub.2CF.sub.2).sub.uCH.sub.2OC(O)C(CH.sub.3).dbd.CH.sub.2,
C.sub.3F.sub.7O(CF(CF.sub.3)CF.sub.2O).sub.uCF(CF.sub.3)CH.sub.2OC(O)CH.d-
bd.CH.sub.2, and
C.sub.3F.sub.7O(CF(CF.sub.3)CF.sub.2O).sub.uCF(CF.sub.3)CH.sub.2OC(O)C(CH-
.sub.3).dbd.CH.sub.2; wherein R.sup.a represents methyl, ethyl or
n-butyl, and u is about 1 to 50.
[0073] Polymeric fluorinated compositions described herein may have
a divalent unit represented by formula III. A divalent unit of
formula III is typically introduced into a polymeric fluorinated
composition by copolymerizing a monomer of formula IIa with a
monomer of the formula (IIIa):
##STR00008## [0074] wherein R.sup.1, R, W, X, Y, and x are as
defined above. In some embodiments of formula IIIa, the groups
R.sup.1, R, Y, and x are those described above for embodiments of a
compound of formula I. In some embodiments, W is alkylene of one to
four carbon atoms. Some monomers of formula IIIa are commercially
available (e.g.,
CH.sub.2.dbd.C(CH.sub.3)C(O)OCH.sub.2CH.sub.2CH.sub.2Si(OCH.sub.3).sub.3
(available, for example, from Union Carbide, New York, N.Y., under
the trade designation "A-174")); others can be made by conventional
synthetic methods.
[0075] Polymeric fluorinated compositions useful in the fracturing
method described herein may optionally include other
interpolymerized divalent units, which may contain hydrophobic,
hydrophilic, or water-solubilizing groups. Useful monomers
(including water-solubilizing monomers) that can be combined with
those of formulas IIa and IIIa include non-fluorinated monomers
described in U.S. Pat. Nos. 6,977,307 (Dams) and 6,689,854 (Fan et.
al.).
[0076] Useful polymeric fluorinated compositions may have a
chain-terminating group represented by formula IV. A
chain-terminating group of formula IV may be incorporated into a
polymeric fluorinated composition, for example, by polymerizing
monomers of formula IIa, optionally IIIa, and optionally at least
one non-fluorinated monomer in the presence of a chain-transfer
agent of the formula (IVa):
HS--W--SiY.sub.3-x(R).sub.x IVa,
wherein R, W, Y, and x are as defined above. In some embodiments of
formula IIIa, the groups R, Y, and x are those described above for
embodiments of a compound of formula I. In some embodiments, W is
alkylene of one to four carbon atoms. Some monomers of formula IVa
are commercially available (e.g., 3-mercaptopropyltrimethoxysilane
(available, for example, from Huls America, Inc., Somerset, N.J.,
under the trade designation "DYNASYLAN")); others can be made by
conventional synthetic methods. A chain-terminating group of
formula IV can also be incorporated into a polymeric fluorinated
composition by polymerizing monomers of formula IIa, optionally
IIIa, and optionally at least one non-fluorinated monomer in the
presence of a hydroxyl-functional chain-transfer agent (e.g.,
2-mercaptoethanol, 3-mercapto-2-butanol, 3-mercapto-2-propanol,
3-mercapto-1-propanol, 3-mercapto-1,2-propanediol) and subsequent
reaction of the hydroxyl functional group with, for example, a
chloroalkyltrialkoxysilane. In a polymerization reaction to make a
polymeric fluorinated composition, a single chain transfer agent or
a mixture of different chain transfer agents may be used to control
the number of polymerized monomer units in the polymer and to
obtain the desired molecular weight of the polymeric fluorochemical
silane.
[0077] The polymeric fluorinated oligomeric composition can
conveniently be prepared through a free radical polymerization of a
fluorinated monomer with optionally a non-fluorinated monomer
(e.g., a water-solubilizing monomer) and at least one of a monomer
containing a silyl group or a chain transfer agent containing a
silyl group using methods known in the art. See, for example, the
methods described in U.S. Pat. Nos. 6,977,307 (Dams) and 6,689,854
(Fan et. al.).
[0078] In some embodiments, the fluorinated silane comprises at
least one fluorinated urethane oligomer of at least two repeat
units (e.g., from 2 to 20 repeating units) comprising at least one
end group represented by the formula --O--Z--Rf.sup.2, and at least
one end group represented by the formula
--X.sup.1--W--SiY.sub.3-x(R).sub.x. In some embodiments, the
fluorinated urethane oligomer of at least two repeat units
comprises at least one end group represented by the formula
--O--(CH.sub.2).sub.nN(R.sup.4)S(O).sub.2--Rf.sup.3, and at least
one end group represented by the formula
--NH--(CH.sub.2).sub.n--SiY.sub.3, wherein Z, Rf.sup.2, R.sup.4,
Rf.sup.3, Y, and x are as defined above, and n is an integer from 1
to 4.
[0079] The term "urethane oligomer" refers to oligomers containing
at least one of urethane or urea functional groups. In some
embodiments, the at least one fluorinated urethane oligomer of at
least two repeat units comprises the reaction product of (a) at
least one polyfunctional isocyanate compound; (b) at least one
polyol; (c) at least one fluorochemical monoalcohol; (d) at least
one silane; and optionally (e) at least one water-solubilizing
compound comprising at least one water-solubilizing group and at
least one isocyanate-reactive hydrogen containing group. In some
embodiments, at least one polyamine may also be used.
[0080] Useful fluorine urethane oligomers may be prepared, for
example, by reaction of at least one polyfunctional isocyanate with
at least one polyol and reaction of the resulting oligomer with at
least one fluorinated monoalcohol and at least one silane.
Exemplary reaction conditions, polyfunctional isocyanates, polyols,
fluorochemical monoalcohols, silanes, and water-solubilizing
compounds are described in U.S. Pat. No. 6,646,088 (Fan et
al.).
[0081] In some embodiments of formula --O--Z--Rf.sup.2, Rf.sup.2 is
a monovalent perfluoroalkyl group described above for Rf in
embodiments of a compound of formula I.
[0082] The divalent organic linking group, Z, in formula
--O--Z--Rf.sup.2, can be a linear, branched, or cyclic structure,
that may be saturated or unsaturated and optionally contains one or
more heteroatoms selected from the group consisting of sulfur,
oxygen, and nitrogen, and/or optionally contains one or more
functional groups selected from the group consisting of ester,
amide, sulfonamide, carbonyl, carbonate, ureylene, and carbamate. Z
includes at least 1 carbon atom and not more than about 25 carbon
atoms (in some embodiments, not more than 24, 23, 22, 21, 20, 19,
18, 17, 16, 15, 14, 13, 12, 11, or even not more than 10 carbon
atoms). In some embodiments of formulas II and IIa, Z is a divalent
organic linking group as described above for divalent Q groups. In
some embodiments of formulas II and IIa, Z is --C.sub.yH.sub.2y--,
--CON(R.sup.1)C.sub.yH.sub.2y--,
--SO.sub.2N(R.sup.1)C.sub.yH.sub.2y--, or
--C.sub.yH.sub.2ySO.sub.2N(R.sup.1)C.sub.yH.sub.2y--, wherein
R.sup.1 is hydrogen or alkyl of one to four carbon atoms, and y is
independently an integer from 1 to 6 (in some embodiments from 2 to
4). In some embodiments, Rf.sup.3 is a perfluoroalkyl group having
from 2 to 5 (e.g., 4) carbon atoms. An end-group of the formula
--O--Z--Rf.sup.2 ((in some embodiments,
--O--(CH.sub.2).sub.nN(R.sup.4)S(O).sub.2--Rf.sup.3) can be
incorporated into a fluorinated urethane oligomer by carrying out
the condensation polymerization reaction (e.g., as described above)
in the presence of a fluorinated monoalcohol of formula
HO--Z--Rf.sup.2.
[0083] Useful fluorinated monoalcohols include, for example,
2-(N-methylperfluorobutanesulfonamido)ethanol;
2-(N-ethylperfluorobutanesulfonamido)ethanol;
2-(N-methylperfluorobutanesulfonamido)propanol;
N-methyl-N-(4-hydroxybutyl)perfluorohexanesulfonamide;
1,1,2,2-tetrahydroperfluorooctanol; 1,1-dihydroperfluorooctanol;
C.sub.6F.sub.13CF(CF.sub.3)CO.sub.2C.sub.2H.sub.4CH(CH.sub.3)OH;
n-C.sub.6F.sub.13CF(CF.sub.3)CON(H)CH.sub.2CH.sub.2OH;
C.sub.4F.sub.9OC.sub.2F.sub.4OCF.sub.2CH.sub.2OCH.sub.2CH.sub.2OH;
C.sub.3F.sub.7CON(H)CH.sub.2CH.sub.2OH;
1,1,2,2,3,3-hexahydroperfluorodecanol;
C.sub.3F.sub.7O(CF(CF.sub.3)CF.sub.2O).sub.1-36CF(CF.sub.3)CH.sub.2OH;
CF.sub.3O(CF.sub.2CF.sub.2O).sub.1-36CF.sub.2CH.sub.2OH; and
mixtures thereof. In some embodiments, the fluorinated monoalcohol
is represented by the formula
HO--(C.sub.nH.sub.2n)N(R.sup.4)S(O).sub.2--Rf.sup.3.
[0084] An end-group of the formula
--X.sup.1--W--SiY.sub.3-x(R).sub.x can be incorporated into a
fluorinated urethane oligomer by carrying out the polymerization
reaction (e.g., as described above) in the presence of a silane of
formula HX.sup.1--W--SiY.sub.3-x(R).sub.x (in some embodiments,
H.sub.2N--(CH.sub.2).sub.n--SiY.sub.3). Useful aminosilanes
include, for example,
H.sub.2NCH.sub.2CH.sub.2CH.sub.2Si(OC.sub.2H.sub.5).sub.3;
H.sub.2NCH.sub.2CH.sub.2CH.sub.2Si(OCH.sub.3).sub.3;
H.sub.2NCH.sub.2CH.sub.2CH.sub.2Si(O--N.dbd.C(CH.sub.3)(C.sub.2H.sub.5)).-
sub.3; HSCH.sub.2CH.sub.2CH.sub.2Si(OCH.sub.3).sub.3;
HO(C.sub.2H.sub.4O).sub.3C.sub.2H.sub.4N(CH.sub.3)(CH.sub.2).sub.3Si(OC.s-
ub.4H.sub.9).sub.3;
H.sub.2NCH.sub.2C.sub.6H.sub.4CH.sub.2CH.sub.2Si(OCH.sub.3).sub.3;
HSCH.sub.2CH.sub.2CH.sub.2Si(OCOCH.sub.3).sub.3;
HN(CH.sub.3)CH.sub.2CH.sub.2Si(OCH.sub.3).sub.3;
HSCH.sub.2CH.sub.2CH.sub.2SiCH.sub.3(OCH.sub.3).sub.2;
(H.sub.3CO).sub.3SiCH.sub.2CH.sub.2CH.sub.2NHCH.sub.2CH.sub.2CH.sub.2Si(O-
CH.sub.3).sub.3; HN(CH.sub.3)C.sub.3H.sub.6Si(OCH.sub.3).sub.3;
CH.sub.3CH.sub.2OOCCH.sub.2CH(COOCH.sub.2CH.sub.3)HNC.sub.3H.sub.6Si(OCH.-
sub.2CH.sub.3).sub.3;
C.sub.6H.sub.5NHC.sub.3H.sub.6Si(OCH.sub.3).sub.3;
H.sub.2C.sub.3H.sub.6SiCH.sub.3(OCH.sub.2CH.sub.3).sub.2;
HOCH(CH.sub.3)CH.sub.2OCONHC.sub.3H.sub.6Si(OCH.sub.2CH.sub.3).sub.3;
(HOCH.sub.2CH.sub.2).sub.2NCH.sub.2CH.sub.2CH.sub.2Si(OCH.sub.2CH.sub.3).-
sub.3; and mixtures thereof.
[0085] In some embodiments, the fluorinated silane comprises at
least one reactive fluorinated silane, as described above, and a
compound of the formula (V):
(R.sup.6).sub.qM(Y.sup.1).sub.p-q V,
wherein M represents an element of valency p+q selected from the
group consisting of Si, Ti, Zr, B, Al, Ge, V, Pb, Sn and Zn (in
some embodiments selected from the group consisting of Ti, Zr, Si
and Al); R.sup.6 represents a non-hydrolysable group (e.g., an
alkyl group of 1 to 20 carbon atoms which may be straight chained
or branched and may include cyclic hydrocarbon structures, a
C.sub.6-C.sub.30 aryl group, optionally substituted by one or more
substituents selected from halogens and C.sub.1-C.sub.4 alkyl
groups, or a C.sub.7-C.sub.30 arylalkyl group); p is 3 or 4
depending on the valence of M; q is 0, 1 or 2; and Y.sup.1
represents a hydrolysable group (e.g., alkoxy, acyloxy, and
halogen). Compounds of formula V and formulations containing
compounds of formula V, fluorinated silanes, and optionally other
crosslinking agents are described, for example, in U.S. Pat. No.
6,716,534 (Moore et al.).
[0086] Representative examples of compounds of formula V include
tetramethoxysilane, tetraethoxysilane, methyl triethoxysilane,
dimethyldiethoxysilane, octadecyltriethoxysilane, methyl
trichlorosilane, tetra-methyl orthotitanate, tetra ethyl
orthotitanate, tetra-iso-propyl orthotitanate, tetra-n-propyl
orthotitanate, tetraethyl zirconate, tetra-iso-propyl zirconate
tetra-n-propyl zirconate. Mixtures of compounds of formula V may
also be used in the preparation of fluorinated silanes.
[0087] Typically the fluorinated silane is dissolved or dispersed
in a dispersing medium (e.g., water and/or organic solvent (e.g.,
alcohols, ketones, esters, alkanes and/or fluorinated solvents
(e.g., hydrofluoroethers and/or perfluorinated carbons)) that is
then applied to at least one of the fracture or proppant (including
in some embodiments, treating the proppant prior to injecting the
proppants into the fracture). The amount of liquid medium used
should be sufficient to allow the solution or dispersion to
generally evenly wet the fracture and/or proppant being treated.
Typically, the concentration of the fluorinated silane in the
solution/dispersion solvent is the range from about 5% to about 20%
by weight, although amounts outside of this range may also be
useful. Some formulations containing fluorinated silanes (e.g., of
formula I) that may be useful are included in U.S. Pat. No.
6,613,860 (Dams et al.). For proppant treated prior to injection
into the fracture, the proppant can be treated, for example, with
the fluorinated silane solution/dispersion at temperatures in the
range from about 25.degree. C. to about 50.degree. C., although
temperatures outside of this range may also be useful. The
treatment solution/dispersion can be applied to the proppant prior
to injection into the fracture using techniques known in the art
for applying solutions/dispersions to particles (e.g., mixing the
solution/dispersion and proppant in a vessel (in some embodiments
under reduced pressure) or spraying the solutions/dispersions onto
the proppant).
[0088] For treatment of the fracture and/or proppant present in the
fracture, the treatment solution/dispersion can be applied using
techniques known in the art for injecting solutions/dispersions to
fractured subterranean formations (e.g., utilizing a coiled a
coiled tubing unit (CTU) or the like).
[0089] In some embodiments, it may be desirable for the treatment
solution to include contain viscosity enhancing agents (e.g.,
polymeric viscosifiers), electrolytes, corrosion inhibitors, scale
inhibitors, and other such additives that are common to a
fracturing fluid.
[0090] After application of the treatment solution/dispersion to
the proppant prior to injection into the fracture, the liquid
medium can be removed using techniques known in the art (e.g.,
drying the particles in an oven). After application of the
treatment solution/dispersion to the proppant present in the
fracture and/or the fracture, the liquid medium can be removed
using techniques known in the art (e.g., allowing the fracture to
begin production of hydrocarbons). Typically, about 0.1 to about 5
(in some embodiments, for example, about 0.5 to about 2) percent by
weight fluorinated silane is added to the proppant and/or fracture,
although amounts outside of this range may also be useful.
[0091] Hydrolysis of the Y groups (i.e., alkoxy, acyloxy, or
halogen) of reactive fluorinated silanes typically generates
silanol groups, which participate in condensation reactions to form
fluorinated siloxanes, for example, according to Scheme I, and/or
participate in bonding interactions with silanol groups or other
metal hydroxide groups on the surface of the proppant particles).
The bonding interaction may be through a covalent bond (e.g.,
through a condensation reaction) or through hydrogen bonding.
Hydrolysis can occur, for example, in the presence of water
optionally in the presence of an acid or base (in some embodiments,
acid). The water necessary for hydrolysis made be added to a
formulation containing the fluorinated silane that is used to coat
the particles (e.g., proppants), may be adsorbed to the surface of
the particles, or may be present in the atmosphere to which the
fluorinated silane is exposed (e.g., an atmosphere having a
relative humidity of at least 10%, 20%, 30%, 40%, or even at least
50%). Water (e.g., brine) may be present in a subterranean
geological formation comprising hydrocarbons and may cause
hydrolysis of hydrolysable groups on a fluorinated silane (and
cause condensation to provide a fluorinated siloxane) during the
injection of particles into a fracture of the formation. The water
present in the subterranean geological formation may be natural
occurring water (e.g., connate water) or water from a man-made
source (e.g., hydraulic fracturing or waterflooding).
##STR00009##
[0092] Under neutral pH conditions, the condensation of silanol
groups is typically carried out at elevated temperature (e.g., in a
range from 40.degree. C. to 200.degree. C. or even 50.degree. C. to
100.degree. C.). Under acidic conditions, the condensation of
silanol groups may be carried out at room temperature (e.g., in a
range from about 15.degree. C. to about 30.degree. C. or even
20.degree. C. to 25.degree. C.). The rate of the condensation
reaction is typically dependent upon temperature and the
concentration of fluorinated silane (e.g., in a formulation
containing the fluorinated silane).
[0093] Techniques for fracturing subterranean geological formation
comprising hydrocarbons are known in the art, as are techniques for
injecting proppants into the fractured formation to prop open
fracture openings. In some methods, a hydraulic fluid is injected
into the subterranean geological formation at rates and pressures
sufficient to open a fracture therein. The fracturing fluid
(usually water with specialty high viscosity fluid additives) when
injected at the high pressures exceeds the rock strength and opens
a fracture in the rock. Proppant can be included in the fracturing
fluid.
[0094] An advantage, in some embodiments, of treated particles
having a plurality of pores is that the treated particle has at
least one of water or oil imbibition up to 95% as compared to a
comparable, untreated particle. The water and oil absorption (i.e.,
water and oil imbibition) of treated proppant can be measured
immersing about 10 grams of the treated proppant in about 20 grams
of deionized water or a tetradecane solution (obtained from
Sigma-Aldrich, St Louis, Mo.), respectively, for about 1 hour. The
water or oil, respectively, is then filtered off with filter paper
(Qualitative Grade 4); Whatman Filter Paper, Florham Park, N.J. The
surface water or oil, respectively, is then carefully removed with
paper towel, and the proppant again weighed. The water or oil,
respectively, absorption is then calculated based on the difference
in weight before and after immersion in the water or oil,
respectively. The water or oil absorption, respectively, is the
average of two measurements.
[0095] Advantages and embodiments of this invention are further
illustrated by the following examples, but the particular materials
and amounts thereof recited in these examples, as well as other
conditions and details, should not be construed to unduly limit
this invention. All parts and percentages are by weight unless
otherwise indicated.
Prophetic Example
[0096] A fracture fluid comprising proppant (e.g., bauxite
particles) is injected into a well in a subterranean formation that
produces hydrocarbons. The fracture fluid is injected at a pressure
that is above the fracture pressure of the formation, resulting in
a fracture and placement of the proppant in the fracture zone. The
fracturing fluid is subsequently produced once the well is opened
for production. Next, a methanolic treatment solution containing 99
percent by weight methanol and 1 percent by weight of fluorinated
silane is injected into the fracture. The treatment solution is
injected into the fracture at a pressure sufficient to wet
substantially the entire fracture and proppant in the fracture, but
not at a pressure high enough to introduce new fractures into the
formation. The treatment remains in the proppant filled fracture
long enough for the silane to treat the fracture and the proppant
(e.g., about 1 hour). The well is then put back on production, and
the treatment fluid is produced, leaving behind the proppant and
fluorinated siloxane.
[0097] Various modifications and alterations of this invention will
become apparent to those skilled in the art without departing from
the scope and spirit of this invention, and it should be understood
that this invention is not to be unduly limited to the illustrative
embodiments set forth herein.
* * * * *