The Key Geological Factors About The Shale Gas Enrichment In Longtan Formation Of Yaojiashan Sectional In Chaohu

Through the key geological factors enrichment of the thickness and distributionof Chaohu Area Yaojiashan sectional Longtan Formation shales, organic mattercontent and type, maturity of organic matter, mineral composition, porosity andpermeability characteristics, such as shale and shale gas adsorption properties,apreliminary analysis of shale gas resource potential, providing a basis for LowerYangtze Region Longtan Formation shale gas exploration. Preliminary analysiscapabilities angry Longtan Formation of shale gas, shale gas resource potential furtherpredicted to provide a basis for the Chaohu area Yaojiashan sectional LongtanFormation shale gas exploration.Shale in Chaohu Yaojiashan Longtan formation in lake sediments between theBay and Delta environment, a thickness of about45m, layer thickness is7.1m;Organic enrichment was concentrated in three ways, enrichment,banded and dispersed;Longtan Formation shale kerogen type is mainlyⅡ2-Ⅲ kerogen, and organic carboncontent of the samples collected by the determination is0.15%-12.57%, the largestorganic carbon content is12.57%. The organic carbon content more than2%of thesample is61.1%, and the average organic carbon content is4.22%. Compared withU.S. Barnett Shale organic carbon content is between3%to13%, Longtan Formationshows a high organic carbon content. The determination of organic vitrinitereflectance ROaverage of1.34%, up2.69%, ranging between1.5%to3.0%, which onthe whole is a high maturity stage. Longtan Formation shales has a higher clay content,increasing the adsorption of shale gas. But the mixed-layer illite clay minerals contentof about60%, Eamon expansion will happen after experiencing mixed layer of water,resulting in decreased reservoir porosity and permeability,which is not conducive tothe exploitation of shale fracturing. Longtan Formation shale porosity averaged is6.14percent, with the main core porosity of shale gas production in North Americadistribution fairly. Permeability is between0.000164-0.0586mD, with a average of0.012mD. Pore size and permeability fractured shale related permeability fractured more, whichis a key factor affecting permeability.Under25℃，c2-1maximum adsorption capacity ofthe sample is4.7965cm3/g, and c4-1is1.4996cm3/g; Under50℃,c4-1maximumadsorption capacity of the sample is1.2017cm3/g. Experimental results show that theadsorption isotherm gas and organic carbon content, proportional to the pressure, andinversely proportional to temperature.