Effect of casing internal pressure on integrity of cement ring in marine shallow formation based on XFEM

摘要

The integrity of cement ring is critical for the safe production of crude oil and natural gas and the protection of marine environment in deep water shallow formation. Due to the poor support of the shallow formation to the cement ring, the cement ring is easily damaged by the casing internal pressure (CIP). Based on extended finite element method (XFEM), the effect of CIP on the integrity of cement ring was investigated in this paper. A casing-cement-formation (CCF) combination model was established. Under different structure and mechanical properties of the cement ring, and different mechanical properties of the shallow formation, the maximum casing internal pressure (MCIP) when cement ring was broken was studied. This paper is of great significance to study the failure mechanism of cement ring integrity in deep water shallow formation, and has guidance for proposing corresponding rationalization suggestions and measures.