Patent ID: 8084402
Filing Date: 2011-12-27
Classification: C09K

Abstract:
1. A method of inhibiting the swelling of clay particulates in a subterranean formation comprising: (a) introducing into the subterranean formation a well treatment composition comprising an ionic liquid entrained in an aqueous fluid, wherein the ionic liquid comprises a cation and an anion, the cation being an imidazolium of formula (I): wherein R 1 and R 2 are independently a C 1 -C 6 alkyl group or a C 1 -C 6 alkoxyalkyl group; R 3 , R 4 and R 5 are independently —H, a C 1 -C 6 alkyl, a C 1 -C 6 alkoxyalkyl group or a C 1 -C 6 alkoxy group; and the anion is selected from the group consisting of X, perchlorate, thiocyanate, cyanate, a C 1 -C 6 carboxylate, an alkyl sulfate, methanesulfonate, BX 4 − , PF 6 − , AsF 6 − , SbF 6 − , NO 2 − , NO 3 − and SO 4 − ; wherein X is a halide; and (b) delivering the aqueous fluid with entrained ionic liquid into the subterranean formation wherein (i) the amount of ionic liquid in the well treatment composition is between from about 0.03 to 0.6 percent by volume; (ii) the ionic liquid is in contact with the formation for a time sufficient to inhibit swelling of clay particulates in the formation; and (iii) the affinity of clay particulates in the formation for the ionic liquid is maintained after treatment of the subterranean formation with the well treatment composition.