Subterranean formations
A method of treating a subterranean formation, for example a subterranean formation susceptible to formation of a undesirable gel-like goo. The method includes contacting the formation with a fluid (A) having a polymer (PP) which includes a pendent group which includes a moiety: wherein the sulphur atom of the moiety is covalently bonded, optionally via a linking atom or group, to the backbone of the polymer.
1 . A method of fracturing a subterranean formation susceptible to formation of an undesirable gel-like goo, the method comprising:
contacting the formation with a fluid comprising a friction reducer polymer that includes a pendent group which includes a moiety:
and has a molecular weight ranging from 1,000,000 to 50,000,000 Daltons, and
minimizing undesirable gel-like goo within the subterranean formation;
wherein the sulphur atom of the moiety is directly covalently bonded or covalently bonded by, a linking atom or linking group to the backbone of the polymer; and
wherein formation water within the subterranean formation includes Total Dissolved Solids (TDS) of at least 5000 ppm; and
wherein formation rock within the subterranean formation includes rock having an Fe(II)S 2 -containing mineral at a level of greater than 0.1 wt % and less than 25 wt %.
2 . The method according to claim 1 , wherein the friction reducer polymer has a polydispersity ranging from 1 to 7.
3 . The method according to claim 1 , wherein the friction reducer polymer has a polydispersity ranging from 1 to 5.
4 . The method according to claim 1 , wherein the friction reducer polymer has a molecular weight ranging from 2,000,000 to 50,000,000 Daltons.
5 . The method according to claim 1 , wherein the friction reducer polymer has a molecular weight ranging from 3,000,000 to 10,000,000 Daltons.
6 . The method according to claim 1 , wherein the moiety of formula (I) is part of formula
and
wherein formula (II) is pendent from a first repeat unit of formula
wherein the carbon atom attached to the oxygen atom is covalently bonded to a moiety which includes said moiety (I) and/or said moiety (II), wherein R1, R2 and R3 independently represent a hydrogen atom or an optionally-substituted alkyl group.
7 . The method according to claim 6 , wherein said polymer includes 2 to 10 atoms in a linking chain between the carbon atom attached to the oxygen atom in moiety (III) and the sulphur atom in moiety (I) and/or (II), wherein a nitrogen atom is included in said linking chain.
8 . The method according to claim 6 , wherein the polymer includes 1 to 100 mol % of first repeat units of formula (III).
9 . The method according to claim 8 , wherein the polymer further comprises second repeat units that are different than the first repeat units of formula (III) and the second repeat units include acrylamide units, wherein the polymer comprises up to 99 mol % of the second repeat units.
10 . The method according to claim 9 , wherein the ratio defined as the mol % of the second repeat units divided by the mol % of the first repeat units is in the range of range of 1 to 50.
11 . The method according to claim 1 , wherein the polymer is a copolymer of acrylamido-methyl-propane sulfonate and acrylamide which includes 5 to 40 mol % of acrylamido-methyl-propane sulfonate repeat units and 60 to 90 mol % of acrylamide repeat units.
12 . The method according to claim 11 , wherein said polymer does not include any phosphonate moiety; and/or does not include any cationic moiety except as part of a zwitterion; and/or does not include any free quaternary ammonium groups.
13 . The method according to claim 9 , wherein the sum of the mol % of said first repeat units and said second repeat units is at least 70 mol %.
14 . The method according to claim 1 , wherein the friction reducer polymer has a polydispersity ranging from 1 to 7 and has a molecular weight ranging from 2,000,000 to 50,000,000 Daltons.
15 . The method according to claim 1 , wherein the friction reducer polymer has a polydispersity ranging from 1 to 5 and has a molecular weight ranging from 3,000,000 to 10,000,000 Daltons.
16 . The method according to claim 1 , wherein the undesirable gel-like goo comprises proppant, clay, residual quasi-iron crosslinked friction reducer, iron-laden asphaltenes, oil, brine, hydrocarbons, or a combination thereof.
17 . The method according to claim 14 , wherein the undesirable gel-like goo comprises proppant, clay, residual quasi-iron crosslinked friction reducer, iron-laden asphaltenes, oil, brine, hydrocarbons, or a combination thereof.
18 . The method according to claim 1 , wherein said moiety (I) is part of a moiety
and a moiety (II) is part of a moiety
wherein X is a hydrogen atom, an alkali metal or NH 4 ;
wherein said polymer includes a repeat unit which includes a moiety
wherein the carbon atom bonded to R2 is bonded to a pendent group which includes said moiety (I) and/or said moiety (II) and R1, R2 and R3 independently represent a hydrogen atom or an optionally-substituted alkyl group.
19 . The method according to claim 18 , wherein said repeat unit of formula (VI) is part of a moiety of formula
wherein L1 is a linking atom or group and wherein, optionally, L1 includes 3 to 6 atoms in a chain between the carbon atom bonded to group R2 and the sulphur atom.
20 . The method according to claim 19 , wherein said polymer includes a repeat unit of formula (VII) wherein L1 represents
21 . The method according to claim 1 , wherein polymer includes a repeat unit derived or derivable from a monomer of the formula
22 . The method according to claim 1 , wherein polymer includes a repeat unit of formula
wherein R11 and R12 are independently selected from a hydrogen atom and an optionally-substituted, alkyl group.
23 . The method according to claim 1 , wherein polymer is a copolymer which includes an acrylamide repeat unit and/or a repeat unit comprising a vinylpyrrolidone moiety.
24 . The method according to claim 14 , wherein said fluid includes 100-10,000 ppm of polymer; and includes up to 95 wt % water, and/or wherein, at some stage in the method, one or a plurality of proppants is incorporated into fluid, wherein the proppant has a size of at least 140 US Mesh and/or said fracturing fluid includes 2.9 to 54 wt % of proppants.
25 . The method according to claim 6 , wherein, at some stage in the method, one or a plurality of proppants is incorporated into fluid, wherein the proppant has a size of at least 140 US Mesh and/or said fracturing fluid includes 2.9 to 54 wt % of proppants.
26 . The method according to claim 10 , wherein, at some stage in the method, one or a plurality of proppants is incorporated into fluid, wherein the proppant has a size of at least 140 US Mesh and/or said fracturing fluid includes 2.9 to 54 wt % of proppants.
27 . The method according to claim 1 , wherein the only polymer for friction reduction in said fluid is said friction reducer polymer and/or said fluid does not include:
any cationic polymer containing a hydrolysable group within a group pendent from the polymer backbone; and/or
any anionic polymer comprising a pendent group that will complex with iron; and/or
any polymer which includes a P-containing functional group.
28 . The method according to claim 1 , wherein the method comprises fracturing a subterranean formation in a method comprising contacting the subterranean formation with a fluid and fracturing the subterranean formation by pumping the fluid into a wellbore at a pressure sufficient to create a fracture network.
29 . The method according to claim 1 , wherein
(a) a pulverized core sample of the subterranean formation has one or more of the following characteristics:
total acid solubility of 15-60 wt %;
HCl solubility of 2-25 wt %; and
HF solubility of 12-50% wt %; and/or
(b) the formation rock includes rock having an Fe(II)S 2 -containing mineral at a level of greater than 0.1 wt %; and/or
(c) said formation rock includes pyrite and/or marcasite; and/or
(d) the formation rock includes feldspar.
30 . The method according to claim 1 , wherein the only polymer for friction reduction in said fluid is said friction reducer polymer and/or said fluid does not include any polymer which includes a P-containing functional group.
31 . A method of fracturing a subterranean formation susceptible to formation of an undesirable gel-like goo, the method comprising:
contacting the formation with a fluid comprising a friction reducer polymer (PP) that includes a pendent group which includes a moiety:
and has a molecular weight ranging from 1,000,000 to 50,000,000 Daltons, and
reducing undesirable gel-like goo within the subterranean formation;
wherein the sulphur atom of the moiety is directly covalently bonded or covalently bonded by a linking atom or linking group to the backbone of the polymer; and
wherein formation water within the subterranean formation includes Total Dissolved Solids (TDS) of at least 5000 ppm; and
wherein formation rock within the subterranean formation includes rock having an Fe(II)S 2 -containing mineral at a level of greater than 0.1wt % and less than 25 wt %.
32 . The method according to claim 31 , wherein the friction reducer polymer has a polydispersity ranging from 1 to 7.
33 . The method according to claim 31 , wherein the friction reducer polymer has a polydispersity ranging from 1 to 5.
34 . The method according to claim 31 , wherein the friction reducer polymer has a molecular weight ranging from 2,000,000 to 50,000,000 Daltons.
35 . The method according to claim 31 , wherein the friction reducer polymer has a molecular weight ranging from 3,000,000 to 10,000,000 Daltons.
36 . The method according to claim 31 , wherein the moiety of formula (I) is part of formula
and
wherein formula (II) is pendent from a first repeat unit of formula
wherein the carbon atom attached to the oxygen atom is covalently bonded to a moiety which includes said moiety (I) and/or said moiety (II), wherein R1, R2 and R3 independently represent a hydrogen atom or an optionally-substituted alkyl group.
37 . The method according to claim 36 , wherein said polymer includes 2 to 10 atoms in a linking chain between the carbon atom attached to the oxygen atom in moiety (III) and the sulphur atom in moiety (I) and/or (II), wherein a nitrogen atom is included in said linking chain.
38 . The method according to claim 36 , wherein the polymer includes 1 to 100 mol % of first repeat units of formula (III).
39 . The method according to claim 38 , wherein the polymer further comprises second repeat units that are different than the first repeat units of formula (III) and the second repeat units include acrylamide units, wherein the polymer comprises up to 99 mol % of the second repeat units.
40 . The method according to claim 39 , wherein the ratio defined as the mol % of the second repeat units divided by the mol % of the first repeat units is in the range of range of 1 to 50.
41 . The method according to claim 31 , wherein the polymer is a copolymer of acrylamido-methyl-propane sulfonate and acrylamide which includes 5 to 40 mol % of acrylamido-methyl-propane sulfonate repeat units and 60 to 90 mol % of acrylamide repeat units.
42 . The method according to claim 41 , wherein said polymer does not include any phosphonate moiety; and/or does not include any cationic moiety except as part of a zwitterion; and/or does not include any free quaternary ammonium groups.
43 . The method according to claim 39 , wherein the sum of the mol % of said first repeat units and said second repeat units is at least 70 mol %.
44 . The method according to claim 31 , wherein the friction reducer polymer has a polydispersity ranging from 1 to 7 and has a molecular weight ranging from 2,000,000 to 50,000,000 Daltons.
45 . The method according to claim 31 , wherein the friction reducer polymer has a polydispersity ranging from 1 to 5 and has a molecular weight ranging from 3,000,000 to 10,000,000 Daltons.
46 . The method according to claim 31 , wherein the undesirable gel-like goo comprises proppant, clay, residual quasi-iron crosslinked friction reducer, iron-laden asphaltenes, oil, brine, hydrocarbons, or a combination thereof.
47 . The method according to claim 44 , wherein the undesirable gel-like goo comprises proppant, clay, residual quasi-iron crosslinked friction reducer, iron-laden asphaltenes, oil, brine, hydrocarbons, or a combination thereof.
48 . The method according to claim 31 , wherein said moiety (I) is part of a moiety
and a moiety (II) is part of a moiety
wherein X is a hydrogen atom, an alkali metal or NH 4 ;
wherein said polymer includes a repeat unit which includes a moiety
wherein the carbon atom bonded to R2 is bonded to a pendent group which includes said moiety (I) and/or said moiety (II) and R1, R2 and R3 independently represent a hydrogen atom or an optionally-substituted alkyl group.
49 . The method according to claim 48 , wherein said repeat unit of formula (VI) is part of a moiety of formula
wherein L1 is a linking atom or group and wherein, optionally, L1 includes 3 to 6 atoms in a chain between the carbon atom bonded to group R2 and the sulphur atom.
50 . The method according to claim 49 , wherein said polymer includes a repeat unit of formula (VII) wherein L1 represents
51 . The method according to claim 31 , wherein polymer includes a repeat unit derived or derivable from a monomer of the formula
52 . The method according to claim 31 , wherein polymer includes a repeat unit of formula
wherein R11 and R12 are independently selected from a hydrogen atom and an optionally-substituted, alkyl group.
53 . The method according to claim 31 , wherein polymer is a copolymer which includes an acrylamide repeat unit and/or a repeat unit comprising a vinylpyrrolidone moiety.
54 . The method according to claim 44 , wherein said fluid includes 100-10,000 ppm of polymer; and includes up to 95 wt % water, and/or wherein, at some stage in the method, one or a plurality of proppants is incorporated into fluid, wherein the proppant has a size of at least 140 US Mesh and/or said fracturing fluid includes 2.9 to 54 wt % of proppants.
55 . The method according to claim 36 , wherein, at some stage in the method, one or a plurality of proppants is incorporated into fluid, wherein the proppant has a size of at least 140 US Mesh and/or said fracturing fluid includes 2.9 to 54 wt % of proppants.
56 . The method according to claim 40 , wherein, at some stage in the method, one or a plurality of proppants is incorporated into fluid, wherein the proppant has a size of at least 140 US Mesh and/or said fracturing fluid includes 2.9 to 54 wt % of proppants.
57 . The method according to claim 31 , wherein the only polymer for friction reduction in said fluid is said friction reducer polymer and/or said fluid does not include:
any cationic polymer containing a hydrolysable group within a group pendent from the polymer backbone; and/or
any anionic polymer comprising a pendent group that will complex with iron; and/or
any polymer which includes a P-containing functional group.
58 . The method according to claim 31 , wherein the method comprises fracturing a subterranean formation in a method comprising contacting the subterranean formation with a fluid and fracturing the subterranean formation by pumping the fluid into a wellbore at a pressure sufficient to create a fracture network.
59 . The method according to claim 31 , wherein
(a) a pulverized core sample of the subterranean formation has one or more of the following characteristics:
total acid solubility of 15-60 wt %;
HCI solubility of 2-25 wt %; and
HF solubility of 12-50 % wt %; and/or
(b) the formation rock includes rock having an Fe (II) S2-containing mineral at a level of greater than 0.1wt %; and/or
(c) said formation rock includes pyrite and/or marcasite; and/or
(d) the formation rock includes feldspar.
60 . The method according to claim 31 , wherein the only polymer for friction reduction in said fluid is said friction reducer polymer and/or said fluid does not include any polymer which includes a P-containing functional group.