摘要
Pores and fractures are important components of flow channels in coal-measure gas reservoirs.While considerable studies have been conducted on pore structure evolution,very few studies have investigated the fracture distribution and self-similarity characteristics.To reveal the characteristics of fracture distribution in coal and shale reservoirs,computed tomography studies were performed on 15 coal and shale samples from the Shanxi and Taiyuan formations.The results show that the fracture distribution of samples of the same lithology differs significantly,and the fracture distribution heterogeneity of shale samples is much higher than that of coal samples.In shale,the heterogeneity of fracture distribution is mainly caused by pores and fractures smaller than 2μm in the z-direction,with relatively little contributions from pores and fractures in the x and y directions.However,the heterogeneity of fracture distribution in coal is mainly controlled by pores and fractures larger than 2μm in all directions,and the difference between the three directions is minor.It was shown that a great number of microscopic pores and fractures contribute to the highest fractions of porosity in different lithological samples.This method is useful for determining the fracture distribution characteristics in shale and coal-measure gas reservoir.
基金
supported by the National Natural Science Foundation of China(Grant Nos.41972171 and 42172156)
the Fundamental Research Funds for the Central Universities(No.2020CXNL11)
the Graduate Innovation Program of China University of Mining and Technology(No.KYCX22_2604)
the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
