Compositions and methods for foam stimulation

Patent metadata

Field	Value
Publication number	US-2021002444-A1
Application number	US-202016922999-A
Country	US
Kind code	A1
Filing date	Jul 7, 2020
Priority date	Jul 7, 2019
Publication date	Jan 7, 2021
Grant date	—

Abstract

Disclosed are foam precursor compositions, foamed compositions, and methods of using these foamed compositions for the stimulation of unconventional reservoirs.

First claim

What is claimed is:

1 . A method for stimulating an unconventional subterranean formation comprising:
(a) providing an existing wellbore in fluid communication with an unconventional subterranean formation, wherein the existing wellbore has a pressure that is less than original reservoir pressure; (b) injecting a foamed composition through the existing wellbore into the unconventional subterranean formation, the foamed composition comprising a surfactant package comprising a primary foaming surfactant and optionally one or more secondary surfactants, wherein the foamed composition is injected at a pressure and flowrate effective to increase the existing wellbore pressure; (c) allowing the foamed composition to contact a rock matrix of the unconventional subterranean formation for a period of time; and (d) producing fluids from the unconventional subterranean formation through the wellbore.

2 . The method of claim 1 , wherein step (b) comprises injecting the foamed composition at a pressure and flowrate effective to:
increase the existing wellbore pressure by at least 30%; increase the existing wellbore pressure to from greater than the original reservoir pressure to 150% of the original reservoir pressure; increase the existing wellbore pressure without refracturing the existing wellbore; or any combination thereof.

3 . The method of claim 1 , wherein step (b) comprises:
combining a foam precursor solution with an expansion gas to form the foamed composition above ground, and injecting the foamed composition through the existing wellbore into the unconventional subterranean formation; or combining a foam precursor solution with an expansion gas downhole to form the foamed composition in situ within the existing wellbore.

4 . The method of claim 1 , wherein the period of time in step (c) comprises a period of time effective to allow the foamed composition to break.

5 . The method of claim 1 , further comprising repeating steps (b)-(d) from 2 to 10 times.

6 . The method of claim 1 , wherein the method further comprises ceasing introduction of the foamed composition through the existing wellbore into the unconventional subterranean formation before allowing step (c).

7 . The method of claim 1 , wherein the existing wellbore has a pressure that is from 20% to 70% of the original reservoir pressure.

8 . The method of claim 1 , wherein the injection of the foamed composition:
increases a relative permeability in a region of the unconventional subterranean formation proximate to the existing wellbore; releases hydrocarbons from pores in a rock matrix in a region of the unconventional subterranean formation proximate to the existing wellbore; or any combination thereof.

9 . The method of claim 1 , wherein the fluids comprise a hydrocarbon and wherein injection of the foamed composition into the unconventional subterranean formation results in increased hydrocarbon recovery from the existing wellbore as compared to an expected level of hydrocarbon recovery projected from a decline curve fit to production history of the existing wellbore, such as using Arp's Equation.

10 . The method of claim 1 , wherein the method remediates near wellbore damage.

11 . The method of claim 1 , wherein the method further comprises ceasing introduction of the foamed composition through the existing wellbore into the unconventional subterranean formation before allowing step (b).

12 . The method of claim 1 , wherein the period of time is from one day to six months, such as from two weeks to one month.

13 . The method of claim 1 , further comprising:
adding a tracer to the foamed composition prior to introducing the foamed composition through the wellbore into the unconventional subterranean formation; recovering the tracer from the fluids produced from the unconventional subterranean formation through the wellbore, fluids recovered from a different wellbore in fluid communication with the unconventional subterranean formation, or any combination thereof; and comparing the quantity of tracer recovered from the fluids produced to the quantity of tracer introduced to the foamed composition.

14 . An aqueous foam precursor composition for use in stimulating an unconventional subterranean formation comprising hydrocarbons, the composition comprising
a surfactant package comprising a primary foaming surfactant and optionally one or more secondary surfactants, wherein the primary foaming surfactant is present in an amount of from 0.1% to 2.5% by weight, such as from 0.25% to 1.5% or from 0.5% to 1%, based on the total weight of the foam precursor composition; and water, wherein the water is present in an amount of 50% or more by weight, based on the total weight of the foam precursor composition; wherein the foam precursor composition exhibits an interfacial tension (IFT) of less than 0.5 dynes/cm, such as an IFT of from 0.05 dynes/cm to 0.5 dynes/cm, between the foam precursor composition and the hydrocarbons present in the unconventional subterranean formation.

15 . The composition of claim 14 , wherein when foamed with an expansion gas to produce a foamed composition having a foam quality of at least 0.8, the foamed composition exhibits an apparent viscosity of at least 1.5 cP at 25° C., such as an apparent viscosity of from 2 cP to 5 cP at 25° C.

16 . The composition of claim 14 , wherein the primary foaming surfactant comprises an anionic surfactant; a cationic surfactant; a non-ionic surfactant; or any combination thereof.

17 . The composition of claim 16 , wherein the primary foaming surfactant comprises a sulfonate surfactant, a disulfonate surfactant, or an alkoxylated C6-C32 alcohol.

18 . The composition of claim 14 , wherein the surfactant package further comprises one or more secondary surfactants, optionally wherein the one or more secondary surfactants comprise a non-ionic surfactant, such as an alkoxylated C6-C32 alcohol.

19 . The composition of claim 14 , wherein the composition further comprises a viscosity-modifying polymer,
optionally wherein the viscosity-modifying polymer comprises a biopolymer such as a polysaccharide; and optionally wherein the viscosity-modifying polymer is present in the foamed composition in an amount of from 0.01% to 1% by weight, based on the total weight of the composition.

20 . The composition of claim 14 , wherein the composition further comprises a foam stabilizer, such as a crosslinker, a particulate stabilizer, or any combination thereof,
optionally wherein the foam stabilizer is present in an amount of from 0.01% to 5%, based on the total weight of the composition.

21 . The composition of claim 14 , wherein the composition further comprises a co-solvent,
optionally wherein the co-solvent comprises a C1-05 alcohol, an alkoxylated C1-05 alcohol, a glycol ether, a polyalkylene glycol, or any combination thereof; and optionally wherein the co-solvent is present in an amount of from 0.01% to 1% by weight, based on the total weight of the foamed composition.

22 . The foamed composition of claim 14 , wherein the composition is substantially free of proppant.

23 . The composition of claim 14 , wherein the composition is foamed and further comprises from 30% to 98% expansion gas, such as from 50% to 98% expansion gas;
optionally wherein the expansion gas comprises air, helium, carbon dioxide, nitrogen, natural gas or a hydrocarbon component thereof, or any combination thereof.

Assignees

• Chevron Usa Inc

Inventors

• Dwarakanath Varadarajan
• Malik Taimur
• Zou Lin
• Zhou Jimin Daniel
• Nizamidin Nabijan
• Winslow Gregory A
• Banki Reza
• Salman Mohamad

Classifications

• E21B43/166

  Injecting a gaseous medium; Injecting a gaseous medium and a liquid medium (CO2 injection E21B43/164; steam injection E21B43/24) · CPC title

• C09K8/94 Primary

  Foams · CPC title

• C09K8/602 Primary

  containing surfactants · CPC title

• C08J9/122 Primary

  Hydrogen, oxygen, CO2, nitrogen or noble gases · CPC title

• C08J2203/06

  CO2, N2 or noble gases · CPC title