Viscoelastic surfactant based wellbore fluids and methods of use

Patent metadata

Field	Value
Publication number	US-9353306-B2
Application number	US-201414576754-A
Country	US
Kind code	B2
Filing date	Dec 19, 2014
Priority date	Jan 10, 2008
Publication date	May 31, 2016
Grant date	May 31, 2016

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 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 starch, wherein the modified starch comprises at least one of corn, wheat, rice, tapioca, sago, waxy maize, waxy rice, sorghum, potato, and pea as a starch source.

2. The method of claim 1 , wherein the wellbore fluid is used to drill a producing interval of the well.

3. The method of claim 2 , wherein a different wellbore fluid is used to drill the well prior to the producing interval.

4. The method 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; X is N, S, or P, and y is 0 or 1.

5. 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 starch, wherein the modified starch comprises at least one of corn, wheat, rice, tapioca, sago, waxy maize, waxy rice, sorghum, potato, and pea as a starch source.

6. The method of claim 5 , 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.

7. 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 starch, wherein the modified starch comprises at least one of corn, wheat, rice, tapioca, sago, waxy maize, waxy rice, sorghum, potato, and pea as a starch source;
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.

8. The method of claim 7 , further comprising
gravel packing at least one interval of the wellbore.

9. The method of claim 7 , further comprising:
circulating a wash fluid through the wellbore prior to and/or after emplacing a breaker fluid.

10. The method of claim 7 , further comprising:
collecting the breaker fluid having at least a portion of the broken invert emulsion filter cake emulsified therein.

11. The method of claim 7 , further comprising:
initiating production of formation fluids through the wellbore.

12. The method of claim 7 , 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.

Assignees

• Mi Llc

Inventors

• Svoboda Charles
• Moore Latosha
• Evans Frank E

Classifications

• C09K8/206 Primary

  Derivatives of other natural products, e.g. cellulose, starch, sugars · CPC title

• E21B43/04

  Gravelling of wells · CPC title

• C09K2208/18

  Bridging agents, i.e. particles for temporarily filling the pores of a formation; Graded salts · CPC title

• C09K2208/30

  Viscoelastic surfactants [VES] · CPC title

• E21B21/003

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