Application of Hydraulic Fracturing Ground Stress Measurement Technology in Operating Pressure Design of Underground Gas Storages

Influenced by the distribution of gas fields in China and the needs of the natural gas market, in recent years, the transformation of oil reservoirs into underground gas storages (UGSs) has gradually developed. In- situ stress is important basic data for the determination of the upper limit pressure design of UGSs, the analysis of fault stability in reservoir areas, and the evaluation of trap tightness. Especially for the reconstruction of UGSs in oil reservoirs, the tightness of the trap is of great significance in the safe operation, management and economic benefits of UGSs. Taking Well M9, an oil reservoir-type UGS in Block M, Nanpu Sag, Bohai Bay Basin, eastern China as an example, this paper introduces the use of hydraulic fracturing (HF) in- situ stress testing technology to obtain the minimum principal stress values of the caprock, reservoir and floor intervals of Well M9. The measured minimum principal stress of the caprock is 72.40–74.27 MPa, and the minimum principal stress of the reservoir is 54.89–60.25 MPa. Because it is an old well, the minimum principal stress of the reservoir is 59.51–64.91 MPa after correction of the in- situ stress measurement according to the theory of elasticity. Based on the comprehensive analysis of the measured in- situ stress data, it is believed that the safe upper limit of the reservoir-type gas storage in Block M of the Nanpu Sag is 45 MPa. Considering the limitations of geological knowledge, there is still a certain uncertainty. It is recommended to use 40 MPa as the M gas storage. Library operating upper limit pressure.