Pore characterization of Upper Ordovician Wufeng Formation and Lower Silurian Longmaxi Formation shale gas reservoirs, Sichuan Basin, China
Pore characterization of Upper Ordovician Wufeng Formation and Lower Silurian Longmaxi Formation shale gas reservoirs, Sichuan Basin, China
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DOI：
10.1016/j.jnggs.2020.11.002
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发表时间：
2020-11
影响因子：
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通讯作者：
Chengfu Lyu;Ying Zhang;Chaowen Li;Guojun Chen;Qianshan Zhou;Ming Ma;Zhaotong Sun;G. Xue
中科院分区：
文献类型：
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作者：
Chengfu Lyu;Ying Zhang;Chaowen Li;Guojun Chen;Qianshan Zhou;Ming Ma;Zhaotong Sun;G. Xue
In order to investigate pore structure characteristics of Wufeng and Longmaxi Formations shales in the Sichuan Basin, the organic geochemical parameter and petrologic experiments, N2and CO2adsorptions, field emission scanning electron microscopy analysis and helium porosity measurement are carried out. Results showed that the thermal maturity of shales belong to over-maturity stage withTOCcontent and porosity of 1.84%–6.82% and 2.6%–5.1%, respectively. TheTOCcontent has a good correlation with quartz, weak correlation with clay and no correlation with carbonate, indicating that the organic matter is mainly controlled by quartz content. The N2and CO2specific surface areas of organic-rich shale is generally 16.86–29.71 m2/g and 13.76–26.47 m2/g, respectively and the average N2and CO2specific surface area of organic-poor shale are 8.91 m2/g and 9.11 m2/g respectively, which indicating that the organic-rich shale has higher specific surface area, pore volume and smaller average pore diameter than that of organic-poor shale. The specific surface area in organic-rich shale is mainly contributed by micropores, while the pore volume is mainly contributed by mesopores, followed by micropores. There is a very strong correlation betweenTOCand CO2and N2specific surface area, indicating that pores were controlled by organic matter. Both porosity and specific surface have a positive relation when clay content is less than 28% for organic-rich shale, and its correlation is not obvious when clay content is more than 28% for organic-poor shale, indicating that the clay has a certain effect on reservoir.
