Progress and Prospect of Geophysical Research on Underground Gas Storage: A Case Study of Hutubi Gas Storage, Xinjiang, China

Hutubi Underground Gas Storage (UGS) is an important part of China''s West-East Gas Pipeline Project. Its production safety also plays an essential role in ensuring peaking, emergency and reserve of natural gas in the region. Geophysical observations and research conducted on Hutubi UGS provide significant support for understanding the operation status and ensuring safe operation of the UGS. Since the beginning of the construction of Hutubi UGS and its production, several works including gas field observation experiments,rock experiments and numerical simulations have been conducted. Preliminary observational results show that during the initial operation stage of the UGS, the "breathing phenomenon" in caprock and microseismicity in the vicinity are closely related to the operation of the gas storage. However,rock experiments and numerical simulations show that these activities may gradually weaken with the multi-cycle operation of gas storage. The impact of the operation of Hutubi UGS in the surrounding areas is gradually weakening, and its operation tends to be stable.Implementing long-term and multi-method geophysical observations is able to provide us a better understanding of the relationship between the operation of UGS and regional geological hazards. On this basis, the corresponding geomechanical model can be established to form an effective risk management mechanism for gas storage operation. Thus, it is of great significance to understand its operation status, monitor storage conditions, guide production and operation, and ultimately guarantee the safe production of the gas storage.