金坛盐穴储气库腔体偏溶特征分析

国内可用于盐穴储气库建设的盐矿以层状盐岩为主，造腔过程中普遍存在腔体偏溶现象，研究其特征及成因对国内以后盐穴储气库的建设具有一定的借鉴作用。以国内第一个盐穴储气库金坛储气库为研究对象，基于声呐测腔数据，提出了以偏溶系数，即腔体最大半径与同一平面最小半径的比值，来定量表征腔体的偏溶程度，最大半径方向即为腔体偏溶方向。统计结果表明，金坛储气库腔体偏溶系数1.13~11.88，偏溶方向以北东南西向为主。结合夹层、可造腔盐层厚度和地应力数据，分析了腔体偏溶发生的原因，认为造腔过程中夹层的不均匀垮塌可促使腔体发生偏溶；可造腔盐层厚度越大，腔体发生偏溶的可能性就越大，偏溶程度就越严重；地应力方向对腔体的偏溶方向具有重要影响。

Characteristics of Cavity Differential Dissolution of Jintan Salt Cave Gas Reservoir

In China, salt mines that can be used for salt cave gas reservoir construction are mostly composed of layered salt rocks, and differential dissolution of the cavity often occurs during solution mining. Research into the characteristics and causes of such phenomenon can provide references for future construction of salt cave gas reservoirs in China. This work investigates the Jintan Salt Cave Gas Reservoir, which is the first salt cave gas reservoir in China. Based on sonar cavity data, differential dissolution in the cavity can be quantitatively analyzed using the differential dissolution coefficient, which is the ratio of the maximum cavity radius to the minimum radius in the same plane. The direction of the maximum radius is the direction of differential dissolution in the cavity. The statistical results reveal that, for the Jintan Gas Reservoir, the differential dissolution coefficient in the cavity is 1.13~11.88, and differential dissolution occurs primarily along the northeast-southwest direction. The causes of differential dissolution in the cavity are analyzed by integrating the thickness and ground stress data of interlayers and salt layers that can be used for mining. It is believed that non-uniform collapses of interlayers during solution mining can lead to differential dissolution in the cavity. Thicker salt layers that are more suitable for mining result in greater likelihood and severity of differential dissolution in the cavity. The ground stress directions significantly influence partial melting in the cavity.