Oil & Gas Geology ›› 2020, Vol. 41 ›› Issue (1): 1-14.doi: 10.11743/ogg20200101

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Distribution, genetic mechanism and control factors of dolomite and dolomite reservoirs in China

Zhiliang He1,2,3(), Yongsheng Ma1,2,*(), Juntao Zhang3, Dongya Zhu3, Yixiong Qian3, Qian Ding3, Daizhao Chen4   

  1. 1. State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, SINOPEC, Beijing 100083, China
    2. China Petroleum & Chemical Corporation, Beijing 100728, China
    3. Laboratory of Structural and Sedimentological Reservoir Geology, Petroleum Exploration and Production Research Institute, SINOPEC, Beijing 100083, China
    4. Key Laboratory of Petroleum Resource Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
  • Received:2019-10-14 Online:2020-02-01 Published:2020-01-19
  • Contact: Yongsheng Ma E-mail:hezhiliang@sinopec.com;mays@sinopec.com
  • Supported by:
    国家自然科学基金重点资助项目(U1663209);国家自然科学基金企业创新发展联合基金项目(U19B6003);国家科技重大专项(2017ZX05005);中国科学院A类战略性先导项目(XDA14010201)

Abstract:

China is one of the few countries in the world where dolomites were developed throughout its geological age. Various types of dolomites can be found from the Proterozoic in North China to the Quaternary salt lake sediments, but the distribution of dolomites is uneven along stratigraphy and across region, with also a great variety in types. The dolomites are widespread in the Lower Paleozoic but become more local features in the Upper Paleozoic, Mesozoic and Cenozoic. The types of dolomitization mainly include microbial (biological), Sabkha, reflux seepage, hydrothermal and mixing zone dolomitization. Because dolomitization is a complicated, long term or intermittence process, even dolomites of the same strata would undergo multiple stages of dolomitization with several types superimposed. Dolomite reservoir is an important oil and gas reservoir in China, featuring variety in types and large time span. In the deep and ancient marine strata series, dolomite is more prone to generate high-quality oil and gas reservoirs compared with limestone. So its importance is even more prominent. Lacustrine dolomites formed in the Late Paleozoic and Meso-Cenozoic are also good in reservoir properties, serving as important reservoirs of unconventional oil and gas. The formation and preservation of dolomite reservoirs are jointly controlled by structure, sequence, lithofacies, fluid, and time.Altogether four types of controlling factors are identified herein:sedimentary facies-controlled para-syndepostional dissolution, ground surface-controlled shallow karstification, fault-controlled reformation in deep burial and deeply buried hydrocarbon dissolution.In all, the factors mentioned, together with different reservoir space generation and accumulation mechanisms, collectively decide the wide type spectrum and the complicated distribution patterns of dolomite reservoirs.

Key words: oil and gas reservoir, genetic mechanism, dolomitization, dolomite, Tarim Basin, Ordos Basin

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