A Comparative Experimental Study of Huff-n-Puff Gas Injection and Surfactant Treatment in Shale Gas-Condensate Cores

Abstract

Experimental and simulation studies have thus far demonstrated that gas injection is an effective way of recovering condensate in shale gas-condensate reservoirs. It is economically feasible and relatively easier to be injected into the tight reservoir as compared to most of the other injection fluids. To the best of our knowledge, surfactant treatment has not been tested in shale cores for gas-condensate fluid systems. In this study, the experimental performances of huff-n-puff gas injection and surfactant treatment are compared in recovering condensate from shale cores. A nonionic fluorocarbon surfactant is screened for experiments based on dynamic contact angle measurements for suitable use in core flooding experiments. The principle of fluorocarbon surfactants is to alter the core from liquid wetting to favorably gas-wetting condition, thus reducing the average condensate saturation trapped in the core. First, an ideal experiment is used to set up two-phase gas and oil flow similar to a gas-condensate...