Oil & Gas Geology ›› 2019, Vol. 40 ›› Issue (2): 236-247.doi: 10.11743/ogg20190203

• Petroleum Geology • Previous Articles     Next Articles

Favorable interval for shale oil prospecting in coring Well L69 in the Paleogene Es3L in Zhanhua Sag,Jiyang Depression,Bohai Bay Basin

Li Zhiming1,2,3, Tao Guoliang1,2,3, Li Maowen1,2,3, Jiang Qigui1,2,3, Cao Tingting1,2,3, Liu Peng1,2,3, Qian Menhui1,2,3, Xie Xiaomin1,2,3, Li Zheng4   

  1. 1. Wuxi Research Institute of Petroleum Geology, Petroleum Exploration and Production Research Institute, SINOPEC, Wuxi, Jiangsu 214126, China;
    2. State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Wuxi, Jiangsu 214126, China;
    3. State Energy Center for Shale Oil Research and Development, Wuxi, Jiangsu 214126, China;
    4. Research Institute of Exploration and Development of Shengli Oilfield Branch Company, SINOPEC, Dongying, Shandong 257015, China
  • Received:2018-03-10 Revised:2018-12-02 Online:2019-04-28 Published:2019-01-23

Abstract:

This paper aims to identify the favorable interval for shale oil prospecting in the cored interval of the lower section of the third member of the Shahejie Formation (Es3L) from Well L69 in Zhanhua Sag,Jiyang Depression,Bohai Bay Basin.To study their oil content and occurrence,typical lithofacies samples from the cored intervals of Es3L in wells with commercial shale oil production,Well L69 and Well XYS9,were comparatively analyzed with routine Rock-Eval pyrolysis method and thermal desorption method,and the favorable interval for shale oil prospecting and factors affecting shale oil production were assessed.Results show that the total content of free oil,especially the content of free oil S1-1 after light hydrocarbon correction,for the organic-rich lamellar argillaceous limestones at a depth of 3 040.35m to 3 072.10m in Well L69,is obviously lower than that of cored interval with commercial shale oil production in Well XYS9,and the average Oil Saturation Index(OSI) is only 67 mg/g,both of which indicate no exploration potential for shale oil.The total content of free oil,especially the content of free oil S1-1 after light hydrocarbon correction,for organic-rich lamellar argillaceous limestones at a depth of 3 116.90m to 3 126.70m in Well L69,is obviously lower than that of cored interval of the Es3(L) with commercial shale oil production from Well XYS9,though the OSIs are usually larger than 100mg/g with an average of 204mg/g,suggesting a lower shale oil exploration potential.The total content of free oil,especially the content of free oil S1-1 after light hydrocarbon correction,and the OSI of organic-rich laminar argillaceous limestones and calcareous mudstones at a depth of 2 994.10m to 3 010.90m in Well XYS9,are similar or almost equal to those of the cored interval of the Es3(L) with commercial shale oil production from Well XYS9; characterized by developed micro-fractures,abnormal pressure,high contents of brittle minerals and contribution of mature oil migration,the cored interval at the depth of 2 994.10m to 3 010.90m should be a favorable interval for shale oil exploration.

Key words: oil content, occurrence, shale oil, Shahejie Formation, Zhanhua Sag, Bohai Bay Basin

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