Kong L.-M.,Petrochina |
Kong L.-M.,Sichuan Provincial Key Laboratory of Shale Gas Evaluation & Exploitation |
Wan M.-X.,Petrochina |
Wan M.-X.,Sichuan Provincial Key Laboratory of Shale Gas Evaluation & Exploitation |
And 12 more authors.
Natural Gas Geoscience | Year: 2015
Based on a large number of thin section identification, scanning electron microscopy analysis, X-ray diffraction tests and some other experiments, the reservoir diagenesis of Silurian Longmaxi Formation in Sichuan Basin were studied. Seven diagenetic processes were identified, including compaction, cementation, clay mineral transformation, replacement, dissolution, organic matter thermal maturation and tectonic disruption. Three kinds of cements (quartz, carbonate and sulfide) were recognized, while the source material of quartz cements and the main factor of forming abandant carbonate cements were summed up. According to single well analysis of N3, it shows that the best, suboptimal and none shale reservoir sections were subjected to different diagenetic transformations. As to best shale reservoir, except for compaction, all the main inorganic diagenesis was significantly related to organic matter maturation. Through comprehensive analysis of diagentic indicators, it is indicated that the reservoir currently has already been in period B of middle diagenetic stage to late diagenetic stage. The inorganic diagenesis has a significant impact on shale reservoir, because it controls not only the conservation, development and evolution of porosity, but also the mechanical property and the adsorption capacity of rocks. However, the organic diagenesis is the source material of shale gas, and it generates a large number of nanoporosity in organic matter, which increase the total porosity and the adsorption capacity of the reservoir. ©, 2015, Science Press. All right reserved.