The study of geostress field has important theoretical and practical significance for the development of shale gas in Nanchuan area.In order to determine the distribution of the current geostress field of Silurian Longmaxi Formation in Nanchuan area

Eastern Chongqing

the maximum horizontal principal stress direction of the current geostress has been determined according to the direction of borehole collapse of key wells in the area

and the magnitude of the geostress of drilled wells has been collected.The distribution of the rock mechanics parameters in the area has been calculated on the basis of the seismic data

the geological units have been divided based on the tectonic map of the bottom of Silurian Longmaxi Formation in Nanchuan area

and a geological model has been established.Taking the ground stress data of key "wells as the constraint

the finite element numerical simulation of the geostress field of Longmaxi Formation in Nanchuan area has been carried out

and the distribution law of the geostress field has been analyzed.The results show that the main stress field is the extrusion stress field.The current maximum principal stress is about NEE25° to SEE20°

56.12-93.79 MPa while the minimum principal stress is approximately NNW25° to NNE20°

48.06～71.67 MPa.On the whole

the stress has a distribution trend of low in the east and high in the west.The fault has an influence on the direction and the magnitude of the stress while the mechanical properties of rocks also influence the stress magnitude.