Oil & Gas Geology ›› 2023, Vol. 44 ›› Issue (1): 213-225.doi: 10.11743/ogg20230118

• Methods and Technologies • Previous Articles     Next Articles

Classified-staged-grouped 3D modeling of multi-scale fractures constrained by genetic mechanisms and main controlling factors: A case study on biohermal carbonate reservoir of the Upper Permian Changxing Fm. in Yuanba area, Sichuan Basin

Xiangyuan ZHAO1(), Yuchun YOU1, Xiangyang HU1, Jingrong LI2, Yu LI2   

  1. 1.Petroleum Exploration and Production Research Institute,SINOPEC,Beijing 102206,China
    2.Exploration and Development Research Institute of Southwest Oil and Gas Branch Company,SINOPEC,Chengdu,Sichuan 610041,China
  • Received:2022-06-05 Revised:2022-11-15 Online:2023-01-14 Published:2023-01-13

Abstract:

Fractures of diverse types and multiple scales are widely distributed in oil/gas reservoirs. They feature multiple stages in terms of origin and different classes in terms of scale under the comprehensive control of various geological factors, posing great challenge for fine 3D geological modeling. The biohermal carbonate reservoir of the Upper Permian Changxing Fm. in Yuanba area, Sichuan Basin is taken as a case to establish a classified-staged-grouped 3D geological modeling method for multi-scale fractures constrained by genetic mechanisms and main controlling factors. It is proposed that the multi-scale fracture modeling should follow the principles of equivalent time constraint, hierarchical constraint and genetic control. According to the actual situation of the study area, geological factors for fracture generation should be fully considered in the modeling process, and a reasonable division scheme for fracture classes and developmental stages should be set for 3D fracture modeling. The large-scale fractures are mainly modeled by the deterministic method, while the medium-to-small-scale fractures are modelled according to their genetic mechanisms and main factors controlling fracture development. Following the understanding of critical geological patterns acquired from the staged and grouped description of fractures with relevant parameters collected, we carry out staged prediction of the medium-to-small-scale fracture distribution by geomechanical method, and then modeling in line with different stages and groups of fractures. Finally, the large-scale fracture model and the medium-to-small-scale fracture model are integrated to obtain the multi-scale fracture network model. Its application to the multi-scale fracture modeling of Changxing Fm. reservoir in Yuanba area shows that the method can effectively make up for the shortcomings of traditional methods in the accuracy of establishing medium-to-small-scale fracture models.

Key words: genetic mechanism, multi-scale fracture, fracture modeling, Changxing Fm., Yuanba area, Sichuan Basin

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