Oil & Gas Geology ›› 2018, Vol. 39 ›› Issue (3): 513-521,600.doi: 10.11743/ogg20180308

Previous Articles     Next Articles

Hydrocarbon expulsion efficiency and oil-bearing property of the shale system in Chang 7 Member,Ordos Basin

Huang Zhenkai1,2, Liu Quanyou1,2, Li Maowen1,2, Chen Jianping3, Li Peng1,2, Zhang Rui4   

  1. 1. State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Beijing 100083, China;
    2. Petroleum Exploration and Production Research Institute, SINOPEC, Beijing 100083, China;
    3. Research Institute of Petroleum Exploration & Development, CNPC, Beijing 100081, China;
    4. College of Geosciences, China University of Petroleum, Qingdao, Shandong 266580, China
  • Received:2018-03-27 Revised:2018-05-03 Online:2018-06-28 Published:2018-06-21

Abstract:

Hydrocarbon expulsion efficiency of the shale system is one of the most important issues in the shale oil and gas research,and also a key parameter for evaluating the potential of shale oil and gas resources.This paper chooses the mud shale system from Chang 7 Member of the Yanchang Formation,Ordos Basin,as the investigation object.It measures the expulsion efficiency of the shale system and also reveals the variation of oil-bearing properties among various lithologies of mud shale system,via systematic geochemical analyses.Their significance in shale oil production is also discussed.The result shows that at the medium maturity stage (Ro=0.8%),the hydrocarbon expulsion efficiency of Type Ⅰ organic mud shale and Type Ⅱ mud shale is 33% to 37% and 16% to 26%,respectively,while at the mature stage (Ro=1.1%),the expulsion efficiency of Type Ⅰ and Type Ⅱ is 64% to 67% and 54% to 58%,respectively.Thus we conclude that in the shale system with higher maturity (Ro=1.1%), the sandstone and silty mudstone with higher free hydrocarbon content and OSI index can be the favorable targets for shale oil exploration and development; the blocky mudstone with high free hydrocarbon content and OSI index would be a potential target for shale oil exploration, with integrated consideration of geological factors including oil-bearing properties of different lithologies, composition characteristics, gas/oil ratio, and fluidity of retained oil. However, the black shale (or pure shale section) might not become an effective target for shale oil exploration in the study area, restrained by some of its geological factors.

Key words: hydrocarbon expulsion efficiency, oil-bearing property, shale, Chang 7 Member, Ordos Basin

CLC Number: