Pore types and microstructure of the black shale in the Lower Silurian, Southeast of Chongqing, China

The Lower Silurian black shale in the Southeast of Chongqing is great potential accumulation gas South China. In order to understand pore system these shales, mercury porosimetry, surface area study, mineralogy and image analyses by scanning electronic microscopy were performed. Four major types (interparticle pores, intraparticle organic-matter pores microfractures) classified under observation samples. Interparticle which associate with mineral particles mostly micro-scale, can be subdivided into among rigid particles, ductile rigid-ductile particles. Intraparticle cleavage-plane within clay minerals, intercrystalline pyrite framboids formed partial or complete dissolution, are nanometer scale more common exist unweathered rocks. Organic-matter one type found organic matter appear prone form effective networks main permeable pathway. rocks abundant microfractures where absorbed transformed free gas. Microfractures partly cemented residual residue importance. Comparing two sets samples from Lujiao section Well Yuye-1, we note that outcrop have much interparticle than core samples, while latter own pores. results quantitative visual qualitative about reservoir similar. With increasing quartz, number macropores increase. And micro-mesopores increase minerals.