China Safety Science Journal ›› 2022, Vol. 32 ›› Issue (2): 74-82.doi: 10.16265/j.cnki.issn1003-3033.2022.02.011

• Safety engineering technology • Previous Articles     Next Articles

Evaluation on sealing performance of mudstone caprocks of gas reservoir-type gas storage in high temperature environment

LUO Zhengshan(), DUAN Yuanzhe, WANG Xiaowan, ZHANG Xinsheng   

  1. School of Management, Xi'an University of Architecture and Technology, Xi'an Shaanxi 710055, China
  • Received:2021-11-28 Revised:2022-01-09 Online:2022-08-18 Published:2022-08-28

Abstract:

In order to explore influence of high temperature on sealing performance of mudstone caprocks, three forms of thermal stress generated by gas storage caprocks were theoretically analyzed. Then, based on laboratory tests, mechanical damage degree of mudstone and changes of caprock sealing assessment indicators in high temperature environment were analyzed. The results show that the overall structural performance of mudstone is reduced under high temperature, with 400 ℃ being generally the threshold temperature for its damage under action of periodic thermal stress. High temperature will significantly change the physical sealing characteristics of mudstone caprocks, and when it is around 400 ℃, which is the threshold, sealing ability will be lost. According to empirical research and analysis results of caprocks in a gas reservoir type gas storage, temperature range of target caprock has not exceeded the threshold. It is believed that the mudstone caprock has good sealing performance, and evaluation result can reflect the true situation of mudstone capping.

Key words: gas reservoir type gas storage, mudstone, caprock sealing, high temperature effect, thermal stress, physical sealing