Xinjiang Petroleum Geology ›› 2025, Vol. 46 ›› Issue (1): 57-63.doi: 10.7657/XJPG20250107

• RESERVOIR ENGINEERING • Previous Articles     Next Articles

Identification and Productivity Prediction of High-Quality Reservoirs in the Metamorphic Buried Hills of the Bozhong 19-6 Structure

TAN Zhongjian1(), GUO Kangliang2, WU Liwei1, ZHANG Guoqiang1, LI Hongru3(), DENG Jinhui1, BI Hongri2   

  1. 1. Tianjin Branch, CNOOC (China) Co., Ltd., Tianjin 300459, China
    2. School of Geosciences, Yangtze University, Wuhan, Hubei 430100, China
    3. CNOOC Energy Technology & Services Limited, Tianjin 300459, China
  • Received:2024-03-31 Revised:2024-05-21 Online:2025-02-01 Published:2025-01-24

Abstract:

In the Bozhong 19-6 structure, fractures serve as the primary flow channels and storage spaces in the metamorphic buried-hill reservoirs, significantly controlling the formation of high-quality reservoirs and well productivity. To accurately identify high-quality reservoirs in the Bozhong 19-6 structure and predict their productivity, fractures were quantitatively characterized using thin sections, imaging logs, and other data. Based on the division of vertical structural units within the buried-hill reservoirs, high-quality reservoirs in the target intervals were identified using conventional mud log, wireline and imaging logging data. The reservoirs were finely evaluated by introducing fracture development index and comprehensive index methods and then a comprehensive method for identifying high-quality reservoirs was established. By substituting the effective thickness and fracture parameters of the high-quality reservoir into productivity evaluation equation, the gas layer productivity of the target intervals was calculated and compared with the test results. It is found that the relative error between the predicted productivity index per meter and the actual productivity values is less than 15%, which indicates a high feasibility of this comprehensive evaluation method in identifying high-quality reservoirs in metamorphic buried hills. This study offers a guidance for oil and gas development in the metamorphic buried hills in the Bozhong 19-6 structure.

Key words: Bozhong 19-6 structure, metamorphic buried-hill reservoir, fracture characteristic, reservoir identification, productivity prediction

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