Oil & Gas Geology ›› 2023, Vol. 44 ›› Issue (5): 1102-1117.doi: 10.11743/ogg20230503

• Petroleum Geology • Previous Articles     Next Articles

Classification and origin of micropores in carbonates and their effects on physical properties of rocks

Haizhou QU1,2,3(), Xinyu GUO1,2, Wei XU4, Wenhao LI5, Song TANG6, Yani DENG7, Shipeng HE8, Yunfeng ZHANG1,2, Xingyu ZHANG4   

  1. 1.School of Geoscience and Technology,Southwest Petroleum University,Chengdu,Sichuan 610500,China
    2.Southwest Petroleum University Branch of the Key Laboratory of Carbonate Reservoirs,China National Petroleum Corporation,Chengdu,Sichuan 610500,China
    3.School of Earth and Space Sciences,Peiking University,Beijing 100871
    4.Exploration and Development Research Institute,PetroChina Southwest Oil & Gas Field Company,Chengdu,Sichuan 610095,China
    5.Petroleum Exploration Division,PetroChina Southwest Oil & Gas Field Company,Chengdu,Sichuan 610095,China
    6.Chuanzhong Oil & Gas Mine,PetroChina Southwest Oil & Gas Field Company,Suining,Sichuan 629000,China
    7.Shu’nan Gas Mine,PetroChina Southwest Oil & Gas Field Company,Luzhou,Sichuan 646000,China
    8.Chuanxibei Gas Mine,PetroChina Southwest Oil & Gas Field Company,Mianyang,Sichuan 621700,China
  • Received:2023-02-26 Revised:2023-05-14 Online:2023-10-19 Published:2023-10-19

Abstract:

Micropores in carbonate rocks are micron- to nano-sized pores with pore sizes less than 50 μm. Various single-factor and comprehensive classification methods for these micropores are available, with Kaczmarek’s comprehensive scheme being widely applied due to its integration of aphanocrystalline morphologies and physical properties. While the fluid intrusion method, image analysis, and mathematical statistics serve as primary characterization methods for micropores, a combination of qualitative and quantitative methods can achieve their comprehensive characterization. Micropores are primarily found between aphanocrystallines or very fine crystallines, primarily growing on primary minerals. Diagenetic processes, especially mineral transformations, dolomitization, and recrystallization, significantly influence micropore formation. Additionally, the morphologies and configurations of aphanocrystallines govern the spatial geometry of micropores, further influencing the physical properties of rocks. As the understanding of micropores in carbonates deepens, it is necessary to refine existing theories about micropore classification and origin by combining the context of China. Furthermore, there is a need to establish and refine the evaluation criteria for rocks of microporous carbonate reservoirs using more advanced characterization techniques such as in-situ microanalytical methods, confocal laser scanning microscopy (CLSM), and digital core modeling. This will be of theoretical and technical support to research on the micro characteristics of deep carbonate reservoirs prevalent in China.

Key words: characterization method, genetic mechanism, physical property, diagenesis, sedimentary facies, micropore, carbonate reservoir

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