新疆呼图壁地下储气库断层气体地球化学特征研究

Rn、CO2、Hg、H2等断层气体被广泛应用于断层活动性以及断层结构特征的研究.当前,研究介质中压力变化与断层气间的关系是断层气映震研究的主要技术方法之一.新疆呼图壁地下储气库自建成以来,每年以周期性循环"注入/采出"模式运行,该运行模式带来的储气库气压变化会影响周围地区的地震活动.同时,这一定期加压存储与减压释放气体...

Geochemical Characteristics of Soil Gas along Faults in Hutubi Underground Gas Storage, Xinjiang

Earthquakes activities can cause the release of underground gas. Soil gases along faults such as radon, carbon dioxide, mercury and hydrogen are widely used in the study of fault activity and the characteristics of fault structure. At present, a great attention has been paid to study the relationship between pressure changes in the medium and gas along fault in studying fault gas reflection. Since the completion of Xinjiang Hutubi Underground Gas Storage, it has been operating in a cyclical "injection/production" mode every year. The gas storage pressure changes caused by such operation mode will have an impact on the seismic activity in the surrounding areas. At the same time of concerning the production and life safety of surrounding residents, this process of regular pressurized storage and decompression of gas release provides a natural testing ground for studying fault gas changes caused by stress changes. In this paper we carried out periodic fault gas measurement and continuous monitoring of fault gas at fixed points in Hutubi gas storage to obtain the fault gas Rn, CO₂, Hg, H₂ of the gas storage and the surrounding area during the repeated loading and unloading of the gas storage. Relatively high concentrations of Hg and H₂ are observed in the gas storage area, with the maximum values of 190ng/m³ and 725.40ppm respectively. In terms of spatial distribution characteristics during the process of pressurized storage in the gas storage, the gas concentration near the injection and production wells in the gas storage area is higher than that outside the gas storage area. In addition, the long-term continuous observation results show that the H₂ has a certain relationship with the pressure change of the gas storage, and has a certain effect on the gas storage, which suggests that the H₂ response to changes in internal pressure is more sensitive. Our results show that analyzing the characteristics of gas changes caused by stress changes in Hutubi gas storage can provide geochemical scientific and technological support to help the survey and selection, construction, earthquake situation tracking and anomaly implementation of seismic stations.