Effects of Quartz Precipitation on the Abundance and Preservation of Organic Matter Pores in Cambrian Marine Shale in South China

To evaluate the effects of quartz precipitation on abundance and preservation organic matter pores in marine shale reservoirs, type authigenic source silica, as well corresponding relation Lower Cambrian Shuijingtuo Formation South China were investigated. Quartz occurs four different types: detrital quartz, replacement biosiliceous debris, euhedral filled interparticle pores, microquartz dispersed a clay matrix. Euhedral (1–5 μm) matrix-dispersed (100–400 nm) are found to be dominant forms quartz. The accumulates along porous fills interior space. Microquartz is mainly wrapped matter. Two silica sources revealed: biogenic clay-derived silica. Biogenic Si most likely major for organic-rich (total carbon (TOC) > 2.55 wt.%) samples, which accounts 23–57 wt.% (average 35 total Si. Based petrographic observations, we posit that large-sized originated from early stage diagenesis provided by observation SEM images indicates diagenetic enhances rock stiffness, buttressing effect can protect compaction during late-stage burial diagenesis. In contrast, late matrix lead reduction capacity accommodation space host retained petroleum, consequently leading development generation gas.