Wellbore stability remains a challenging task in the oil and gas industry, especially for the wells completed with open hole technology during the production stage. In this research, a three-dimensional poro elasto plastic finite element model is built using a non-linear finite element software ABAQUS purposely to investigate the wellbore stability during the production stage of buried hill wells in Bozhong 26–6 Oilfield under open hole completion condition. A numerical simulation model of wellbore stability in the whole life cycle of the development well was first established by combining well completion parameters, production development plan and rock mechanics experiment results. Then, the boundary conditions of the model were set up according to the reservoir physical properties and the development plan of the field. Finally, the relationship between the stress state around the wellbore and the production year was obtained and the calculation method of collapse pressure and wellbore collapse volume was established. The results showed that the collapsed volume of the model increased by 43.75% after integration of fracture in the model. The plastic equivalent strain (PEEQ) and the normalized wellbore radius of the model with and without fracture always remained below respectively the critical plastic equivalent strain and the critical normalized wellbore radius of the model which demonstrated that there is no obvious collapse of the borehole wall during the whole life of production. This study investigates the wellbore stability under open hole completion during the production stage in the Bozhong 26–6 oilfield which is a new field where this investigation has seldom been examined in the literature.