Reservoir Evaluation and Development ›› 2021, Vol. 11 ›› Issue (2): 190-196.doi: 10.13809/j.cnki.cn32-1825/te.2021.02.007

• Shale Gas Exploration • Previous Articles     Next Articles

Characteristics of geostress field of Longmaxi Formation in Nanchuan area, Eastern Chongqing

ZHANG Douzhong1,2(),TANG Jiguang2,CAI Jun2   

  1. 1. Hubei Cooperative Innovation Center for Unconventional Oil and Gas, Yangzte University, Wuhan, Hubei 430100, China
    2. School of Geosciences, Yangzte University, Wuhan, Hubei 430100, China
  • Received:2020-09-21 Online:2021-04-26 Published:2021-04-30

Abstract:

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.

Key words: Nanchuan area, Longmaxi Formation, current geostress, finite element, numerical simulation

CLC Number: 

  • TE122