Influences of Shale Rheology on Pore Structures of Qiongzhusi Formation in Chengkou Area, Northeastern Sichuan Basin

doi:10.7657/XJPG20220502

Abstract

Abstract:

In order to determine the influence of natural rheology of shale on microscopic pore structure, taking the marine shale of the Lower Cambrian Qiongzhusi formation in the Chengkou area, northeastern Sichuan basin as an example, the types and characteristics of rheological structure and microscopic pore structure in the shale and their relationship were studied by using rock thin sections, focused ion beam scanning electron microscope and low temperature liquid nitrogen adsorption experiment. The microstructures of shale rheology mainly include porphyroclast system, cataclastic flow, pressolutional stylolites, microscopic fold, S-C fabric and crenulation cleavage, and the micro-nano structures include mylonite zone, micro-hybrid zone, and rotating porphyroclast. Rheological shale is dominated by nanoscale intergranular pores, and most of the primary pore structure is difficult to preserve under rheological action. Ductile rheology leads to a decrease in the number of pores, pore diameter, pore volume and pore specific surface area of shale, which reduces the storage performance of shale.

Key words: Sichuan basin, Chengkou area, Cambrian, Qiongzhusi formation, shale rheology, pore structure, shale gas reservoir

CLC Number:

TE122

YU Shuyan, WANG Yang, FENG Hongye, ZHU Hongjian. Influences of Shale Rheology on Pore Structures of Qiongzhusi Formation in Chengkou Area, Northeastern Sichuan Basin[J]. Xinjiang Petroleum Geology, 2022, 43(5): 513-518.

Figures/Tables 6

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