CA2469988A1

CA2469988A1 - Carbon dioxide foamed fluids

Info

Publication number: CA2469988A1
Application number: CA 2469988
Authority: CA
Inventors: Yiyan Chen; Jesse Lee; Timothy Pope
Original assignee: Schlumberger Canada Ltd
Current assignee: Schlumberger Canada Ltd
Priority date: 2003-12-05
Filing date: 2004-06-04
Publication date: 2005-06-05
Anticipated expiration: 2024-06-04
Also published as: CA2469988C

Abstract

An aqueous viscoelastic surfactant (VES) fluid foamed or energized with carbon dioxide, in which the VES is more compatible with the carbon dioxide, is made by the addition of one or more than one synergistic co-surfactant. The synergist co-surfactant includes quaternary amines and ethoxylated carboxylates having a hydrophobic chain shorter than the hydrophobic chain of the VES. Improved compatibility is evidenced for a given surfactant concentration either by formation and maintenance of a foam under conditions at which the foam could not otherwise have been formed or maintained, or by either higher viscosity of the foamed fluid at a given temperature or longer foam life at a given temperature or a higher temperature at which useful fluid viscosity can be generated or maintained for a useful time. The aqueous carbon dioxide foamed fluids may be used in acidizing, acid fracturing, gravel packing, diversion, and well cleanout.

Claims

1. A fluid composition comprising a viscoelastic surfactant and a synergistic co-surfactant.

2. The fluid composition of claim 1 further comprising water, wherein said viscoelastic surfactant is present in a concentration of from about 0.3 to about 10 %, and said synergistic co-surfactant is present in a concentration of from about 0.008 to about 4 %.

3. The fluid composition of claim 1 wherein the ratio of surfactant to synergistic co-surfactant is from about 5:1 to about 15:1.

4. The fluid composition of claim 2 further comprising carbon dioxide in a separate phase.

5. The fluid composition of claim 4 wherein the viscoelastic surfactant and the synergistic co-surfactant co-operatively stabilize the carbon dioxide-water interface.

6. The fluid composition of claim 4 wherein the synergistic co-surfactant improves the compatibility of the viscoelastic surfactant with the carbon dioxide.

7. The fluid composition of claim 4 wherein the foam quality is from about 30 to about 80%.

8. The fluid composition of claim 1 wherein the viscoelastic surfactant is a zwitterionic surfactant.

9. The fluid composition of claim 8 wherein the zwitterionic surfactant has the formula:
RCONH-(CH2)a(CH2CH2O)m(CH2)b-N+(CH3)2-(CH2)a'(CH2CH2O)m'(CH2)b'COO-wherein R is an alkyl group that contains from about 17 to about 23 carbon atoms which may be branched or straight chained and which may be saturated or unsaturated;
a, b, a', and b' are each from 0 to 10 and m and m' are each from 0 to 13, provided that both m and m' are not equal to 0; a and b are each 1 or 2 if m is not 0 and (a + b) is from 2 to 10 if m is 0; a' and b' are each 1 or 2 when m' is not 0 and (a' + b') is from 1 to 5 if m' is 0;
(m + m') is from 1 to 14; and CH2CH2O may also be OCH2CH2.

10. The fluid composition of claim 9 wherein the surfactant is a betaine.

11. The fluid composition of claim 10 wherein the betaine is selected from oleylamidopropyl betaine and erucylamidopropyl betaine.

12. The fluid composition of claim 1 wherein said synergistic co-surfactant comprises a molecule having one or more than one of a region attracted more to carbon dioxide than to water and one or more than one of a region attracted more to water thane to carbon dioxide.

13. The fluid composition of claim 11 wherein the synergistic co-surfactant is selected from the group consisting of i) a quaternary amine surfactant, and mixtures of quaternary amine surfactants, wherein the cation is selected from:
and mixtures thereof, and oligomers thereof and polymers thereof;
and and mixtures thereof, and oligomers thereof and polymers thereof;
and mixtures thereof, wherein R1, R2, R3, and R4 are each selected from the group consisting of alkyl, alkenyl, arylalkenyl, and hydroxyalkyl, each having from 1 to about 22 carbon atoms and being saturated or unsaturated and branched or straight chained, and wherein R1 is further selected from the group consisting of alkylaminoalkyl and alkylamidoalkyl, and ii) an ethoxylated anionic surfactant having the general formula:
R - (CH2CH2-O)n-COO-M+
and mixtures thereof, and oligomers thereof and polymers thereof, wherein R is an alkyl chain having from about 6 to about 22 carbon atoms, that can be straight chained or branched, and saturated or unsaturated and further wherein n has a value of from about 0 to about 30; and iii) mixtures thereof.

14. The fluid composition of claim 11 wherein said synergistic co-surfactant is selected from polypropylene oxide and vinyl alcohol vinyl acetate copolymer.

15. The fluid composition of claim 12 wherein the surfactant is BET-E-40 and the synergistic co-surfactant is selected from the group consisting of C12 alkyl dimethyl benzyl ammonium chloride, sodium laureth-13 carboxylate and mixtures thereof.

16. The fluid composition of claim 2 further comprising zirconium oxychloride.

17. A method of increasing the compatibility of an aqueous fluid comprising the surfactant of claim 8 with carbon dioxide comprising adding a sufficient amount of the synergistic co-surfactant of claim 11.

18. A method of treating a subterranean formation penetrated by a wellbore comprising injecting the fluid composition of claim 1 into said formation.

19. A method of treating a wellbore comprising injecting the fluid composition of claim 1 into said wellbore.