Salt-out in porosity medium: Mitigating gas channeling using alcoholinduced salt precipitation

摘要

To eliminate the adverse effects of gas coning occurring during the condensate filed exploitation, alcohol-induced salt precipitation was used as the method to mitigate gas channeling. The predecessor's researches only focused on the ordinary mechanism which is the salt precipitation caused by ethanol inducing, but it was not able to explain a marked decrease in permeability after a long term gas injection. In this paper, a novel theory is presented, the permeability change is the result of two mechanism act synergistically, first is the salt precipitation caused by ethanol inducing, another mechanism also takes an important role in mitigating gas coning which is drying-out mechanism. For lager Peclet, the salt deposition was non homogeneous and accumulated near the surface, the salts distribution in the porosity medium was measured by experiment testing and a simple model calculation.