Risk Analysis of Casing Deformation in Shale Gas Wells: A Case Study from the Jingyan Block

Abstract Deformation of shale gas wells casing has hindered the progress of fracturing operations, becoming a significant challenge in field development. Current risk assessment methods for casing deformation in shale gas wells are not only complex and difficult to model but also lack the necessary speed and convenience for field applications. To address these challenges, this study takes the Jingyan block as a practical case study and proposes a casing deformation risk assessment method based on the Analytic Hierarchy Process (AHP). In establishing the indicator system for casing deformation, qualitative methods are applied to rapidly identify the categories of primary influencing factors, resulting in an indicator system that includes natural fractures zones, geological heterogeneity, geostress, and brittle mineral content. Subsequently, a judgment matrix is constructed using the indicator system to calculate the weight values of each indicator. A risk assessment formula for casing deformation is then established. Finally, during the risk assessment process, quantitative methods are employed to determine the risk level of casing deformation using precise numerical values. Research results demonstrate that in the specific application of this block, the method successfully simplified the complex decision-making problem, which was previously difficult to address, into a multi-level single-objective problem. It also enabled a hierarchical quantitative analysis of the qualitative indicators obtained. This systematic approach integrates the influence of various factors on the results, achieving an 88.83% consistency rate compared with actual casing deformation stage in the field and verifying its reliability in field application. This study provides a new method for predicting the high-risk stages of casing deformation. The approach not only offers a clear and straightforward process with predictable results that are readily usable by decision-makers but also provides reference for optimizing fracturing construction designs in subsequent stages.