Use of a borate-acid buffer in oil and gas operations

Patent metadata

Field	Value
Publication number	US-2022333003-A1
Application number	US-202217853283-A
Country	US
Kind code	A1
Filing date	Jun 29, 2022
Priority date	Jul 31, 2018
Publication date	Oct 20, 2022
Grant date	—

Abstract

Provided herein are compositions comprising borate-acid buffers, as well as methods of using these compositions in oil and gas operations, including enhanced oil recovery (EOR) operations, fracturing operations, stimulation operations, etc.

First claim

1 - 20 . (canceled)

21 . A method for stimulating a subterranean formation, the method comprising:
introducing an aqueous composition comprising (i) a borate-acid buffer, (ii) a surfactant package, a water-soluble polymer, or a combination thereof, and (iii) water into the subterranean formation through a wellbore in fluid communication with the subterranean formation; and allowing the aqueous composition to imbibe into a rock matrix of the subterranean formation for a period of time.

22 . The method of claim 21 , wherein the method further comprises producing fluids from the subterranean formation through the wellbore.

23 . The method of claim 21 , wherein the subterranean formation comprises an unconventional subterranean formation.

24 . The method of claim 21 , wherein the method further comprises ceasing introduction of the aqueous composition through the wellbore into the subterranean formation before said allowing step.

25 . The method of claim 21 , wherein the period of time is from one day to six months.

26 - 27 . (canceled)

28 . The method of claim 21 , further comprising:
adding a tracer to the aqueous composition prior to introducing or along with the aqueous composition or through the wellbore into the subterranean formation; recovering the tracer from the fluids produced from the subterranean formation through the wellbore, from fluids produced from a different well in fluidic communication with the subterranean formation, or any combination thereof; and comparing the quantity of tracer recovered from the fluids produced to the quantity of tracer introduced.

29 . The method of claim 21 , wherein the borate-acid buffer is present in the aqueous composition in an amount of from 0.01% to 2% by weight, based on the total weight of the aqueous composition.

30 . The method of claim 21 , wherein the borate-acid buffer exhibits a capacity to buffer at a pH of from 6.0 to 8.5.

31 . The method of claim 21 , wherien the borate-acid buffer exhibits a capacity to buffer at a pH below a point of zero charge of the subterranean formation.

32 - 40 . (canceled)

41 . The method of claim 21 , wherein the borate-acid buffer comprises a borate compound and a conjugate base of an acid, wherein the borate compound and the conjugate base of the organic acid are present at a weight ratio of from 1:1 to 5:1.

42 - 49 . (canceled)

50 . The method of claim 21 , wherein the aqueous composition comprises a surfactant package, and wherein the surfactant package comprises a primary surfactant and optionally one or more secondary surfactants.

51 . The method of claim 50 , wherein the primary surfactant comprises an anionic surfactant selected from a sulfonate, a disulfonate, a sulfate, a disulfate, a sulfosuccinate, a disulfosuccinate, a carboxylate, a dicarboxylate, or any combination thereof.

52 . (canceled)

53 . The method of claim 51 , wherein the anionic surfactant comprises one of the following:
a branched or unbranched C6-C32:PO(0-65):EO(0-100)-carboxylate; a C10-C30 internal olefin sulfonate; a C8-C30 alkyl benzene sulfonate (ABS); a sulfosuccinate surfactant; a surfactant defined by the formula below
R 1 —R 2 —R 3

wherein R 1 comprises a branched or unbranched, saturated or unsaturated, cyclic or non-cyclic, hydrophobic carbon chain having 6-32 carbon atoms and an oxygen atom linking R 1 and R 2 ; R 2 comprises an alkoxylated chain comprising at least one oxide group selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, and combinations thereof; and R 3 comprises a branched or unbranched hydrocarbon chain comprising 2-12 carbon atoms and from 2 to 5 carboxylate groups; or a surfactant defined by the formula below

wherein
R 4 is, individually for each occurrence, a branched or unbranched, saturated or unsaturated, cyclic or non-cyclic, hydrophobic carbon chain having 6-32 carbon atoms; and
M represents a counterion.

54 - 55 . (canceled)

56 . The method of claim 50 , wherein the primary surfactant has a concentration within the composition of from 0.05% to 5% by weight, based on the total weight of the aqueous composition.

57 - 91 . (canceled)

92 . The method of claim 21 , wherein the hydrocarbons further comprise CO 2 , H 2 S, or any combination thereof.

93 . The method of claim 21 , wherein when present the water-soluble polymer comprises a synthetic polymer.

94 . The method of claim 21 , wherein when present the water-soluble polymer comprises polyacrylamide or a copolymer thereof.

95 . The method of claim 21 , wherein the surfactant package comprises a primary surfactant comprising a branched or unbranched C6-C32:PO(0-65):EO(0-100)-carboxylate, a dicarboxylate, or any combination thereof.

96 . The method of claim 21 , wherein the borate-acid buffer is present in an effective amount to chelate divalent metal ions present in the water or in water present in the subterranean formation.

97 . The method of claim 21 , wherein the subterranean formation comprises a conventional subterranean formation.

Assignees

• Chevron Usa Inc

Inventors

• Nizamidin Nabijan
• Pinnawala Gayani W
• Tang Guo-Qing
• Dwarakanath Varadarajan
• Winslow Gregory A
• Isbell Jordan Taylor
• Malik Taimur

Classifications

• C09K8/602

  containing surfactants · CPC title

• E21B47/11

  using tracers; using radioactivity · CPC title

• C09K8/584 Primary

  characterised by the use of specific surfactants · CPC title

• C09K8/66

  Compositions based on water or polar solvents (C09K8/64 takes precedence) · CPC title

• E21B43/20

  Displacing by water · CPC title