Viscoelastic surfactant based wellbore fluids and methods of use

Patent metadata

Field	Value
Publication number	US-8937034-B2
Application number	US-81147809-A
Country	US
Kind code	B2
Filing date	Jan 7, 2009
Priority date	Jan 10, 2008
Publication date	Jan 20, 2015
Grant date	Jan 20, 2015

Abstract

A wellbore fluid that includes an aqueous based fluid; an amphoteric, viscoelastic surfactant; and a modified starch is disclosed. Methods of drilling subterranean wells, methods of reducing the loss of fluid out of subterranean wells, and methods of completing wellbores using aqueous-based fluids having an ampoteric, viscoelastic surfactant and a modified starch are also disclosed.

First claim

What is claimed:

1. A wellbore fluid, comprising:
an aqueous based fluid;
an amphoteric, viscoelastic surfactant; and
a modified potato starch, wherein the modified starch comprises a potato starch treated with a crosslinking agent.

2. The wellbore fluid of claim 1 , further comprising:
bridging particles.

3. The wellbore fluid of claim 1 , wherein the amphoteric surfactant comprises a compound represented by the general structure:

where R1, R2, R3, R4, and R5 are carbon chains, saturated or unsaturated, straight, branched, or cyclic including aromatic groups, R1 contains 8-26 carbons, R2 contains 2-10 carbons, and R3, R4, and R5 contain 1-6 carbons; Xis N, S, or P, and y is 0 or 1.

4. The wellbore fluid of claim 3 , wherein the amphoteric surfactant comprises at least one alkylamidopropyl betaine.

5. The wellbore fluid of claim 1 , wherein the modified starch comprises at least one of etherification, esterification, crosslinking, or combinations thereof.

6. The wellbore fluid of claim 1 , wherein the modified potato starch comprises a potato starch crosslinked with at least one of epichlorohydrin, phosphorus oxychloride, adipic-acetic anhydrides and sodium trimetaphosphate.

7. The wellbore fluid of claim 1 , wherein the aqueous based fluid comprises fresh water, sea water, brine, mixtures of water and water-soluble organic compounds and mixtures thereof.

8. The wellbore fluid of claim 1 , further comprising:
at least one miscible amine.

9. A method of drilling a subterranean well, comprising:
drilling the subterranean well using a rotary drilling rig and circulating a wellbore fluid in the subterranean well, wherein the wellbore fluid comprises:
an aqueous based continuous phase;
an amphoteric, viscoelastic surfactant; and
a modified potato starch.

10. The method of claim 9 , wherein the wellbore fluid is used to drill a producing interval of the well.

11. The method of claim 10 , wherein a different wellbore fluid is used to drill the well prior to the producing interval.

12. The method of claim 9 , wherein the amphoteric surfactant comprises a compound represented by the general structure:

where R1, R2, R3, R4, and R5 are carbon chains, saturated or unsaturated, straight, branched, or cyclic including aromatic groups, RI contains 8-26 carbons, R2 contains 2-10 carbons, and R3, R4, and R5 contain 1-6 carbons; X is N, S, or P, and y is 0 or 1.

13. A method of reducing the loss of fluid out of a subterranean well, comprising:
injecting into the subterranean well a wellbore fluid comprising:
an aqueous based continuous phase;
an amphoteric, viscoelastic surfactant; and
a modified potato starch.

14. The method of claim 13 , wherein the amphoteric surfactant comprises a compound represented by the general structure:

where R1, R2, R3, R4, and R5 are carbon chains, saturated or unsaturated, straight, branched, or cyclic including aromatic groups, R1 contains 8-26 carbons, R2 contains 2-10 carbons, and R3, R4, and R5 contain 1-6 carbons; X is N, S, or P, and y is 0 or 1.

15. A method of completing a wellbore, comprising:
drilling the wellbore with a wellbore fluid to form a filter cake on the walls thereof, the wellbore fluid comprising:
an aqueous based continuous phase;
an amphoteric, viscoelastic surfactant; and
a modified potato starch;

emplacing a breaker fluid into the wellbore; and
shutting in the well for a period of time sufficient to initiate breaking of the filter cake.

16. The method of claim 15 , further comprising
gravel packing at least one interval of the wellbore.

17. The method of claim 15 , further comprising:
circulating a wash fluid through the wellbore prior to and/or after emplacing a breaker fluid.

18. The method of claim 15 , further comprising:
collecting the breaker fluid having at least a portion of the broken invert emulsion filter cake emulsified therein.

19. The method of claim 15 , further comprising:
initiating production of formation fluids through the wellbore.

20. The method of claim 15 , wherein the amphoteric surfactant comprises a compound represented by the general structure:

where R1, R2, R3, R4, and R5 are carbon chains, saturated or unsaturated, straight, branched, or cyclic including aromatic groups, R1 contains 8-26 carbons, R2 contains 2-10 carbons, and R3, R4, and R5 contain 1-6 carbons; X is N, S, or P, and y is 0 or 1.

21. The wellbore fluid of claim 1 , further comprising at least one amine selected from the group consisting of triethanolamine, methyldiethanol amine, dimethylethanol amine, diethanol amine, and monoethanol amine.

Assignees

• Svoboda Charles
• Moore Latosha
• Evans Frank E
• Mi Llc

Inventors

• Svoboda Charles
• Moore Latosha
• Evans Frank E

Classifications

• C09K8/08 Primary

  containing natural organic compounds, e.g. polysaccharides, or derivatives thereof · CPC title

• E21B21/003

  Means for stopping loss of drilling fluid (plastering the borehole wall E21B33/138) · CPC title

• C09K2208/30

  Viscoelastic surfactants [VES] · CPC title

• E21B43/04

  Gravelling of wells · CPC title

• E21B43/16

  Enhanced recovery methods for obtaining hydrocarbons · CPC title