An Analysis Method of Gas Injection Development Effect in the Single well Fractured-Vuggy System

In this study, we propose an analysis method of gas injection development effect in the single well fractured-vuggy system. The fractured-vuggy reservoir has a complex spatial structure, oil-water relations and connectivity, of which single well fractured-vuggy system is a simpler model. Aiming at the problems of low recovery rate and production difficulties, based on the elasticity theory and fluid mechanics in porous, the elastic expansion energy and oil-water interface change before and after gas injection in the single well developing fractured-vuggy system are analyzed. And a theoretical mode of development effect after gas injection is built. Then an example analysis of Tarim Oilfield is conducted. The results show that: mining after repeated gas injection, water cut significantly decreased, yield and water free production increases gradually and the replacement rate increases with the gas injection. This shows that gas injection can effectively inhibit the rise of oil-water interface and improve the development effect of fractured-vuggy system.