Lithofacies Characteristics and Pore Controlling Factors of New Type of Permian Unconventional Reservoir in Sichuan Basin

Alongside volcanic eruptions in the middle and late Permian, sedimentary environment process changed, lithofacies characteristics varied conspicuously marine deposits of Sichuan Basin (China). The tuffaceous rocks, as a new type unconventional reservoir, provide strong evidence for influences on lithology reservoir potential rocks. With experimental studies relying field outcrops, thin sections, scanning electron microscopy whole-rock X-ray diffraction (XRD), researchers analyzed characteristics, pore types controlling factors various pores We identified three this Permian Basin, namely tuff, mudstone. mineral composition includes quartz, feldspar, carbonate minerals, pyrite, clay, among which feldspar is mainly potassium feldspar. Tuff has high tuff content, lowest clay TOC content; mudstones have highest content. rocks are nano-scale shrinkage pores, with small number intergranular including intragranular organic pores. account 81.9% total 11.2% In quartz pyrite content inversely correlated porosity, while positively porosity. porosity lowest, followed by mudstone highest. Tuffaceous form many micropores devitrification. Organic matter pyrolysis acid dissolution also increase space reservoir. This ability hydrocarbon accumulation along performance, thus it greater exploration prospects.