Characterization of natural fractures and reservoir reconstruction strategy for continental shale oil reservoir in Ordos Basin

doi:10.3969/j.issn.1672-7703.2024.03.012

Abstract

Abstract: The shale oil reservoir in the seventh member of the Triassic Yanchang Formation (Chang 7 member) in Longdong area in Ordos Basin is mainly composed of alternating deposits of deep lacustrine shale and gravity flow sand bodies, with complex and variable reservoir distribution both vertically and laterally, and thin single sand body. In addition, influenced by natural fractures, there are a number of challenges in scientific fracturing engineering and production operation in the area. Some engineering problems such as pressure channeling and sand plugging, as well as cost reduction and production increase, are important research topics at present. The work and understanding on the characterization of natural fractures in the area in the past two years are summarized, and the latest concepts and strategies in fracturing reconstruction are introduced. On the basis of comprehensive geological study, 3D fine geological, oil reservoir, and geomechanical models have been established, and rational fracturing design, construction, post fracturing analysis, and computer simulation have been conducted to better understand the interaction between natural fractures and hydraulic fractures and the propagation law of hydraulic fractures, achieving the customized fracturing design and construction optimization. After field application, the amounts of proppant and fracturing fluid have been reduced by about 20% and 10%, respectively, given the similar oil production between the construction well and adjacent wells on the same platform. The workflow with integration of geology and engineering enables the implementation of “one well, one strategy” and “one section, one method”. In the long run, it will be the fundamental technical guarantee for achieving the best EUR of single well and well platform for continental shale oil in Ordos Basin.

CLC Number:

TE319

Lei Qihong, Ma Fujian, He Youan, Wang Shuyu, Niu Li, Luo Yin, Ye Po, Huang Tianjing, Huang Zheyuan, Liu Yuan, Feng Zhangbin. Characterization of natural fractures and reservoir reconstruction strategy for continental shale oil reservoir in Ordos Basin[J]. China Petroleum Exploration, 2024, 29(3): 130-145.

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