Cement interface failure analysis of underground gas storage wellbores based on abaqus with implemented cohesive modeling
Abstract
Aiming at the problems of wellhead uplift and casing–cement sheath interfacial failure in gas storage injection–production wells under cyclic operating conditions, this study analyzes the damage evolution of the bonding interface and the resulting wellhead uplift by considering the multi-string casing structure and thermo-mechanical coupling effects of the wellbore. Based on modeling verification and numerical simulation using Abaqus, a quantitative characterization method for cementing quality is proposed. The interfacial damage evolution can be divided into three stages: “intact bonding control → rapid damage propagation → complete debonding and slip”. The microscopic failure of the bonding interface progresses segment by segment from top to bottom. Under constant temperature conditions, the wellhead uplift increases significantly with the reduction of the effective bonding area, while the maximum uplift is positively correlated with the input temperature. The damaged area is negatively correlated with the actual bonding area. The critical safe bonding area should exceed 40%, and a value of 75% is recommended when considering engineering efficiency.