Abstract:
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.