METHOD FOR IMPROVING CO_2 INJECTIVITY BY DECREASING IRREDUCIBLE WATER SATURATION NEAR WELLBORE IN UNDERGROUND STORAGE

摘要

According to the present invention, a method for improving the injectivity of an underground gas storage layer, comprises the steps of: injecting a reducing agent for lowering a residual water saturation level of a storage layer through an injection well, connected to a underground gas storage layer composed of water-permeable rock; and storing carbon dioxide by injecting the same in the storage layer after injecting the reducing agent. The method can improve the carbon dioxide injectivity of the storage layer by discharging water and a reducing agent which are filled in a cavity of the storage layer, with respect to the injection of carbon dioxide, and lowering a residual water saturation level around an injection well. In the present invention, as the reducing agent, a surfactant or a substance which can be miscible in both carbon dioxide and water can be used.