US 4,391,925 A · Shear thickening well control fluid

Abstract

The instant invention is directed to shear thickening fluids which comprise a water swellable clay capable of rapidly forming a paste having a strength of at least 2000 lbs/100 ft.sup.2 upon interaction with the aqueous phase employed and present in sufficient concentration to form such a paste, a nonaqueous phase comprising a hydrocarbon material and surfactant, and an aqueous phase comprising water and a water-soluble polymer, wherein the clay and the aqueous phase are kept separated by the intervening hydrocarbon-surfactant phase. The intervening oil phase prevents the interaction between the water-polymer phase and the clay and results in a stable, non-reacting, pumpable composite, until such time as the oil barrier is ruptured by deliberate application of a sufficiently high shear force. Upon such rupture, the materials interact resulting in a semi-rigid high strength paste.

Claims28

Dependent claims

A shear thickening composite comprising:

(a) a water swellable clay capable of rapidly forming a high strength gel when mixed with water, said clay being present in said composite in sufficient quantity so as to form a gel having a strength of at least 2000 lb/100 ft.sup.2 ;
(b) a first phase comprising water and water soluble polymer;
and
(c) a second phase comprising oil and surfactant, the water in said first phase being kept separate from said clay by the intervening second phase, said intervening second phase remaining intact during low shear pumping of the composite, said intervening second phase rupturing during the application of high shear to the composite to enable mixing of the water in the first phase and the clay to form the high strength gel.

1 more element

A method for treating a well penetrating a subterranean formation to block off unwanted flow paths comprising introducing into said well a shear thickening composite stable to pumping comprising a water swellable material capable of rapidly forming a still paste when mixed with a water-water soluble/water swellable polymer solution, an oil-surfactant phase and a water-water soluble/water swellable polymer phase wherein the water swellable material, present in sufficient quantity so as to form a paste having a strength of at least 2000 lb/100 ft.sup.2, and the water-polymer solution are kept separated, by the intervening oil-surfactant phase, and subjecting said shear thickening composite to high shear mixing thereby rupturing the intervening oil-surfactant phase, mixing the water swellable material and the water-polymer causing it to thicken into a high strength semi-rigid paste which blocks off unwanted flow paths.

Dependencies are inferred from the claim text.

Shear thickening well control fluid

Life of this patent

Shear thickening well control fluid

Life of this patent

Abstract

Claims28