Additive for viscoelastic fluid
AssigneeSchlumberger Technology Corporation
InventorsYiyan Chen, Jesse C. Lee
Life of this patent
Estimating the term…
Abstract
Composition and method for shortening the shear recovery time of cationic, zwitterionic, and amphoteric viscoelastic surfactant fluid systems by adding an effective amount of a co-gelling agent selected from triblock oligomeric compounds having hydrophilic (for example polyether) and hydrophobic (for example alkyl) portions. The co-gelling agent also increases fluid viscosity and very low co-gelling agent concentration is needed. Preferred surfactants are betaines and quaternary amines. The fluids are useful in oilfield treatments, for example fracturing and gravel packing.
Claims18
-28. (canceled)
An aqueous oilfield treatment composition comprising a viscoelastic surfactant and a co-gelling agent wherein the co-gelling agent has a structure selected from the group consisting of H(CH2)x(OCH2CH2)yO(CH2)zH, H(CH2)xCO(OCH2CH2)yOCO(CH2)zH, HO(CH2CH2O)x,CO(CH2)y,CO(OCH2CH2)z,OH, and HO(CH2CH2O)x,(CH2)y,(OCH2CH2)z,OH, in which y is from about 10 to about 50, preferably from about 24 to about 36;
- y′ is from about 4 to about 50, preferably from about 6 to about 24;
- x and z are from about 6 to about 22, preferably from about 8 to about 16;
- and x′ and z′ are from about 1 to about 50, preferably from about 3 to about 40, and further wherein the values of x and z, and of x′ and z′, may be the same.
The composition of claim 1 wherein the concentration of the co-gelling agent is from about 0.005 to about 0.075%.
Dependencies are inferred from the claim text.