Microemulsion flowback aids for oilfield uses

摘要

Flowback aid mixtures and oil-in-water microemulsions produced by combining an aqueous brine with the flowback aid mixtures are disclosed. The flowback aid mixture comprises an oil, a fatty alcohol ethoxylate, and a quaternized fatty amine ethoxylate. The amount of oil is less than or equal to 12 wt. % based on the amount of flowback aid mixture. The microemulsions have a surface tension at 25° C. less than 30 mN/m and a Z-average particle size as determined by dynamic light scattering at 25° C. of less than or equal to 10 nm. Also disclosed are processes that utilize the flowback aid mixtures. In one process, the mixture is introduced into a subterranean formation and is combined prior to or during its introduction into the formation with a formation brine, process water, or both to give the microemulsion. In one hydraulic fracturing process for recovering gas, oil, or both, a fracturing fluid and the flowback aid are co-injected into a subterranean formation to give the microemulsion.