Abstract: Jingyan-Qianwei Qiongzhusi has a huge amount of silty shale gas resources. The target layer in this area has a large burial depth, complex geological structure, and high horizontal stress values in the reservoir. Some wells experienced severe casing deformation during the fracturing process, resulting in lost sections and seriously affecting single well production. Based on the characteristics of casing deformation failure and the analysis of common engineering and geological influencing factors in the deformed well section, a numerical simulation model of formation casing cement ring fracturing was established to clarify the mechanism of casing deformation. A set of risk assessment methods for casing deformation is established based on critical injection pressure, formation stress state, and corresponding fracturing fracture state. The risk of casing deformation is classified, forming a balanced fracturing and casing deformation prevention technology system of "fine optimization+real-time warning+three control mode". The technology is finely segmented, and real-time warning is used through microseismic monitoring. The risk section controls the scale, displacement, and operation rhythm. The application results show that the technology system can effectively reduce the occurrence of casing deformation and provide technical support for the development of the area's benefit scale.

Key words: deformation of casing, section loss, deformation mechanism, real time warning, three control mode