Abstract:

Through the studies using SEM, Ar-ion mille FESEM and NMR technologies, the characteristics of the formation of micron-size pores, nanoscale pores and microfractures of the Longmaxi Formation shales were quantitatively characterized. Based on the test data of TOC, Ro, and X-ray diffraction analysis of mineral composition, the controlling factors of forming characteristics of the above three kinds of pores were analyzed. The positive factors for the development of micron-size pores are quartz content and illite content, and the negative factors are depth and carbonate content. The positive factors for the development of organic matter pores are Ro and illite, smectite content, and the negative factor is calcite content. The positive factors for the development of micro-fractures are quartz content, Ro and TOC, and the negative factor is calcite content.

Key words:  shale gas, reservoir, pore, Longmaxi Formation, controlling factor