Casing failure mechanism and slip anchoring optimization of the compression packer in the oil and gas well

The packer is a key tool to isolate downhole pressure during well testing and completion operations. The compression packer in the oil and gas wellbore needs to be anchored by hard contact between the slips and the casing when setting, which will cause the casing to suffer from occlusal damage and shorten the working life. It is necessary to combine casing damage and anchoring performance of the slip, select suitable packer slip material, and optimize its structural parameters to reduce casing hard contact damage and increase the working life of the slips and casing. Based on mechanical analysis and hard contact mechanism of the slip during the packer setting process, and selecting the slip material lower than the mechanical properties of the casing material, a finite element analysis model of interaction between the slips and the casing was established. The changes of slip equivalent plastic strain, maximum Mises stress, and CPRESS stress under three parameters of slip tooth number, tooth space, and tooth top angle were comprehensively evaluated. The results of analysis show that with the increase in the tooth number of slips, the tooth space or the top angle, the bending moment of slips increased, and the anchoring performance decreased. As the tooth number of slips, the tooth space or the top angle decreased, the damage of slip teeth increased. The combination optimization analysis of the above parameters was carried out using the orthogonal experiment method, and the optimal top angle of the slip structure of the compression packer is 90°, the tooth space is 4 mm, and the tooth number is 20. Compared with the anchoring performance of soluble metal slips, the optimized slips significantly reduce the damage to the casing. The study will provide a theoretical basis and date support for further analysis of the anchoring performance of the slip, the reduction of casing damage, and the design of new slips.