二氧化碳作天然气地下储气库垫层气的可行性  

Feasibility of Using Carbon Dioxide as Cushion Gas in Underground Natural Gas Storage

作　　者：杜思宇 柏明星[1,2] 张志超[1,2] 刘敬源 刘业新 DU Si-yu;BAI Ming-xing;∗;ZHANG Zhi-chao;LIU Jing-yuan;LIU Ye-xin(College of Petroleum Engineering,Northeast Petroleum University,Daqing 163318,China;Northeast Petroleum University,Key Laboratory of Enhanced Oil Recovery of the Ministry of Education,Daqing 163318,China)

机构地区：[1]东北石油大学石油工程学院,大庆163318 [2]东北石油大学提高采收率教育部重点实验室,大庆163318

出　　处：《科学技术与工程》2024年第27期11663-11670,共8页Science Technology and Engineering

基　　金：国家自然科学基金面上项目(52174020)。

摘　　要：CO_(2)用作天然气地下储气库垫层气,在储气库运行过程中,注采参数等因素不合理导致CO_(2)与天然气之间过渡混合和天然气采收率低等问题。开展了CO_(2)和CH_(4)物性对比及混气实验,论证了CO_(2)作垫层气的可行性;建立储气库二维模型,模拟CO_(2)作垫层气注采过程,对影响CO_(2)-CH_(4)混合程度的地层参数和运行参数进行分析。研究结果表明:CO_(2)垫层气比例不超过20%,采出气中CO_(2)摩尔含量不高于3%,CO_(2)-CH_(4)混合程度、储层平均压力下降幅度较小。渗透率越大,工作气回采携带CO_(2)垫层气量越多,实际CO_(2)垫层气量占比减小,CO_(2)垫层气量不足以为工作气开采提供“助力”。孔隙度对CO_(2)-CH_(4)混合程度几乎没有影响。合理控制采气速度能有效抑制混合带发展,即在用气高峰适当提高采气速度,用气低谷减小采气速度保证最低用气标准。研究结果为CO_(2)作天然气地下储气库垫层气的工程实践提供理论指导。CO_(2)is used as a cushion gas for underground natural gas storage reservoirs,and during the operation of the gas storage,unreasonable injection and production parameters and other factors lead to the problems of transitional mixing between CO_(2)and natural gas and a low natural gas recovery rate.The comparison of physical properties of CO_(2)and CH_(4),and the visible phase reactor were carried out to demonstrate the feasibility of CO_(2)as cushion gas.A two dimensional model of the gas storage reservoir was established to simulate the process of CO_(2)as cushion gas injection and production,and the formation parameters and operating parameters affecting the mixing degree of CO_(2)-CH_(4)were analyzed.The results show that the proportion of CO_(2)cushion gas is not more than 20%,the molar content of CO_(2)in produced gas is not more than 3%,the mixing degree of CO_(2)-CH_(4)and the average reservoir pressure drop are small.The higher the permeability,the more CO_(2)cushion gas carried by working gas recovery,the smaller the proportion of actual CO_(2)cushion gas,and the insufficient CO_(2)cushion gas to provide“power”for working gas recovery.Porosity has little effect on the mixing degree of CO_(2)-CH_(4).Reasonable control of gas production rate can effectively inhibit the development of mixed zones.In other words,the gas production rate should be increased at the peak of gas consumption,and the gas production rate should be reduced at the trough to ensure the minimum gas consumption standard.The research results provide theoretical guidance for the engineering practice of using CO_(2)as cushion gas in underground natural gas storage.

关 键 词：CO_(2)垫层气 混气实验 性质差异 混合带 

分 类 号：TE822[石油与天然气工程—油气储运工程]