Adjacent well casing damage caused by fluid pressure intrusion in multistage fracturing

Abstract

Nowadays, the large cluster well factory production mode is widely applied, which means that multistage fracturing can cause casing damage not only to the construction well but also to the adjacent well. To explore the cause of casing deformation caused by fluid pressure intrusion in multistage fracturing, a three-dimensional model of multistage fracturing in two wells is established based on natural fractures. The new model has reached dimensions of 1500 m × 300 m × 100 m, essentially achieving a 1:1 scale modeling. In addition, on the basis of large-scale modeling, adjacent wells have been taken into consideration for the first time. The multistage fracturing construction is simulated through the Abaqus finite element model. Results indicate that the multistage fracturing construction of a well not only transforms the stratum near the well, but also the extended hydraulic fractures have a certain effect on the stratum of neighboring wells at a close distance, causing natural fractures near the neighboring wells to slip. In this study, the control variable method was used to evaluate different influencing factors, determine the relationship between influencing factors and adjacent casing deformation, and put forward optimization design suggestions, which provided a reference for preventing and controlling casing deformation caused by fluid pressure intrusion.