天然气地下储气库CO_(2)作垫层气研究现状

Research status of CO_(2) as cushion gas in underground natural gas storage

针对天然气地下储气库垫层气的相关研究,从CO_(2)和CH_(4)的热力学性质对比以及相关混气实验,综述了CO_(2)作垫层气的可行性。从静态因素和动态因素两个方面,详细综述了CO_(2)作垫层气与工作气混合的影响因素,包括储层孔隙度、渗透率、温度、压力、CO_(2)垫层气比例等。论述了“CO_(2)-地层水-岩石”相互作用对储层结构和稳定性的影响。研究可为CO_(2)作天然气地下储气库垫层气的注采动态变化规律分析以及提高储气库天然气采收率提供理论借鉴。

The feasibility of CO_(2) as cushion gas is summarized from the comparison of thermodynamic properties of CO_(2) and CH_4,and related gas mixing experiments,aiming at the relevant research on cushion gas of underground natural gas storage.From the aspects of static and dynamic factors,the influencing factors of CO_(2) as cushion gas mixing with working gas are systematically discussed,including reservoir porosity,permeability,temperature,pressure,CO_(2) cushion gas ratio,etc.The influence of gas-brine-sandstone interaction on reservoir structure and stability is discussed.This study can provide a theoretical reference for the analysis of injection and production performance of CO_(2) as cushion gas in underground matural gas storage and the improvement of gas recovery in gas storage.