Study on the Distribution Law of Near-Wellbore in-situ Stress and Casing Load under Fracturing Conditions

In order to study the casing damage mechanism and the influencing factors of casing load under hydraulic fracturing conditions, rock mechanics tests were carried out, and a multi-field coupled finite element analysis model of casing, cement sheathe, formation, and fracture was established. Distribution law and influencing factors of near-wellbore in-situ stress and casing load under hydraulic fracturing propagation were analyzed. The results showed that the natural fractures in the reservoir caused the non-uniform propagation of hydraulic fractures, and the casing was subjected to a non-uniform load. The in-situ stress difference increased and the elastic modulus decreased while the near-wellbore in-situ stress and casing load increased. The influence of the natural fracture number and the distribution pattern of natural fractures on the near-wellbore in-situ stress and casing load were complicated. The research results provide a theoretical basis for optimizing the cementing design and fracturing design of shale reservoirs and reducing casing damage.