岩穴储气库的天然气存储能力分析

An analysis of the storage capacity of rock cavern repository for natural gas

为深入了解岩穴储气库的天然气储气能力及库容可利用率,假定储气库内各部位天然气的温度相同以及储气库周围的岩体为同一介质,基于能量和质量守恒原理,考虑天然气的真实可压缩性,研究了定容岩穴储气库内压缩天然气的温度和压力变化过程,进而提出了岩穴地下储气库库容和储气能力的计算方法,并分析了垫底气压力大小对岩穴储气库的储气能力及库容可利用率的影响。研究表明:随垫底气压力增大,岩穴储气库的总储气量相应增加,注采比和库容可利用率则呈现出先增加后减小的变化趋势,且在垫底气压力约为3.0 MPa时,库容可利用率达到最大值。采气完成后的待储阶段,储气库内天然气的压力出现了逐渐恢复现象;垫底气压力增大,天然气压力恢复程度越小;垫底气压力大于3.0 MPa后天然气压力恢复值逐渐趋于稳定。研究结论可为各类天然气储气库的可行性研究与设计提供理论指导。

This study aimed to clarify the natural gas storage capacity and storage capacity availability of cavern repositories,assuming that the temperature of natural gas in each part of the gas storage was the same and that the rock mass around the gas storage was the same medium.Based on the principle of the conservation of energy and mass,and considering the real compressibility of natural gas,the temperature,and pressure change processes of compressed natural gas in constant-volume cavern gas storage were studied.Furthermore,the calculation method for the storage capacity and the gas storage capacity of a rock cavern for gas storage was proposed.The influence of cushion gas pressure on the gas storage capacity and storage capacity availability of cavern repositories were also analyzed.The results indicated that the cavern repositories'total gas storage capacity increased as the cushion gas pressure increased.Moreover,the injection-production ratio and the storage capacity availability exhibited a trend in which it initially increased before decreasing.When the cushion gas pressure was approximately 3.0 MPa,the storage capacity availability reached the maximum value.Once the gas production stage was completed,the pressure in natural gas stores gradually recovered.As the pressure of the cushion gas increased,less of the natural gas pressure would be recovered.The pressure recovery value of natural gas gradually stabilized once the cushion gas pressure was higher than 3.0 MPa.The study's conclusions provide good theoretical guidance for the feasibility of research and design approaches for various rock-cavern repositories for natural gas storage.