Oil & Gas Geology ›› 2019, Vol. 40 ›› Issue (3): 504-511.doi: 10.11743/ogg20190306

• Petroleum Geology • Previous Articles     Next Articles

Progresses in geophysical characterization of continental shale oil sweet spots

Liu Xiwu1,2,3,4, Liu Yuwei1,2,3,4, Liu Zhiyuan1,2,3,4, Song Liang5, Liu Jiong1,2,3,4, Huo Zhizhou1,2,3,4, Zhang Jinqiang1,2,3,4, Qian Keran1,2,3,4, Zhang Yingyan6   

  1. 1. State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Beijing 100083, China;
    2. State Energy Center for Shale Oil Research and Development, Beijing 100083, China;
    3. Key Laboratory of Shale Oil and Gas Exploration & Production, SINOPEC, Beijing 100083, China;
    4. Petroleum Exploration and Production Research Institute, SINOPEC, Beijing 100083, China;
    5. Geophysical Prospecting Research Institute, Shengli Oilfield Branch Company Ltd., SINOPEC, Dongying, Shandong 257015, China;
    6. Geophysical Prospecting Research Institute, Jianghan Oilfield Branch Company Ltd., SINOPEC, Wuhan, Hubei 430033, China
  • Received:2018-12-20 Revised:2019-02-28 Online:2019-06-28 Published:2019-04-26

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Abstract: There are still many challenges on geophysical characterization of continental shale oil sweet spot in Eastern China in terms of technique applicability.Petrophysical models for continental shale oil layers are established to analyze geophysical responses based on the study on the fundamentals of continental shale oil.It's believed that the controlling factors for shale oil accumulation are organic-rick laminated lithofacies and fractures,following the integrated investigation of geology,well logging and geophysics.Besides,based on the existing methods for seismic prediction including lithofacies,TOC,rock physical property,oil bearing properties,brittleness,pore pressure and in-situ stress,new geophysical prediction methods are built for laminated lithofacies,fracture and in-situ stress.Based on petrophysical models and anisotropy pre-stack inversion,new methods are developed to predict the density of bedding-parallel fractures in shale,which is in turn regarded as a constraint for sedimentary analysis,so as to effectively predict the distribution of the laminated lithofacies.Orthorhombic anisotropy AVAZ algorithm is given to improve the seismic characterization of fractures;while the prediction of in-situ stress is achieved based onYoung's modulus,bulk modulus,and modulus of rigidity,and the direction of in-situ stress can be computed from interval velocity variation.The study clarifies the main controlling factors for continental shale oil sweet spots,establishes an index system for sweet spots,reveals the characteristics of petrophysical and geophysical responses of sweet spots,and optimizes the geophysical characterization method for sweet spots.These methods are successfully used to identify the favorable target areas for continental shale oil exploration in Jiyang Depression.

Key words: lithofacies, fracture, in-situ stress, petrophysics, geophysical characterization, continental shale oil sweet spot, Jiyang Depression

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