Xinjiang Petroleum Geology ›› 2025, Vol. 46 ›› Issue (5): 544-552.doi: 10.7657/XJPG20250503

• OIL AND GAS EXPLORATION • Previous Articles     Next Articles

Identification of Fault-Karst Bodies in Permian Maokou Formation in Jingyan Area, Southwestern Sichuan Basin

LI Suhua(), LU Qijun, HU Hao, LI Rong, SU Chengpeng, JIANG Nengchun   

  1. Research Institute of Exploration and Development, Southwest Oil & Gas Company, Sinopec, Chengdu, Sichuan 610041, China
  • Received:2024-12-02 Revised:2024-12-20 Online:2025-10-01 Published:2025-09-30

Abstract:

The distribution of fault-controlled karst reservoirs in the Permian Maokou formation in the Jingyan area of southwestern Sichuan Basin remains unclear. A seismic identification model for faults and fault-karst bodies in the Maokou formation was established using drilling, geological, seismic and other data. The differences in seismic reflections between faults and fault-karst bodies were analyzed through forward modelling. On this basis, multi-stage superimposed faults were identified using seismic structural attributes such as coherence, maximum likelihood, dip angle and gradient structure tensor etc., and interlayer fault-karst bodies were recognized from seismic texture attributes such as entropy and energy. Then the distribution of Maokou formation fault-controlled karst reservoirs was accurately determined, and a geological development model was established. The results indicate that the study area mainly develops two types of fault-controlled karst reservoirs: multi-stage superimposed fault-karst bodies, which are observed in the southern part of the study area, and interlayer fault-karst bodies, which are developed in the eastern part of the study area. The seismic structural attributes can be used to accurately recognize high, steep and upright multi-stage superimposed fault-karst bodies that exhibit significant differences in the continuity of seismic waveforms, while the seismic texture attributes can be used to accurately represent gentle and low-angle interbedded fault-karst bodies with obvious changes in reflection amplitude energy of seismic waveforms. The predicted results are consistent with actual drilling results, and the research results can guide the future exploration deployment.

Key words: Sichuan Basin, Permian, Maokou formation, fault-controlled karst reservoir, fault-karst body, seismic structural attribute, seismic texture attribute

CLC Number: