巢湖地区龙潭组过渡相煤系页岩储层发育特征

Longtan Formation Transitional Facies Coal Measures Shale Reservoir Development Features in Caohu Area

应用有机碳测试、X射线衍射、氩离子抛光-场发射扫描电镜、液氮吸附及高压压汞等实验技术手段,对巢湖地区龙潭组过渡相煤系页岩储层特征进行了研究。结果表明:龙潭组煤系页岩主体TOC质量分数为0. 5%～12. 5%,垂向向下有机碳含量呈现增长趋势,镜质组反射率Ro为1. 2%～2. 8%,有机质类型属腐殖型;矿物主要由黏土矿物和石英组成,其平均质量分数分别为35%,27%;龙潭组页岩孔隙主要发育有机质孔隙、黏土矿物片间孔隙、矿物溶蚀孔等多种类型;微孔、小孔极为发育,提供了主要的孔隙比表面积与孔体积。龙潭组储层孔隙特征主要受控于沉积环境与成岩作用,黏土矿物组分和有机质的演化控制纳米孔隙发育,三角洲沼泽相、泥坪相与泻湖相是有利于龙潭组煤系页岩储层发育的沉积环境。

Using organic carbon test, X - ray diffraction, argon ion polishing - field emission scanning electron microscope, low tem- perature nitrogen adsorption and high pressure mercury injection experiment technical means carried out research on the Longtan Forma- tion transitional facies coal measures shale reservoir features in the Caohu area. The result has shown that Longtan Formation coal meas- ures shale principal part TOC mass fraction is 0. 5% - 12. 5% , vertically downward, organic carbon content presents increasing trend, vitrinite reflectanceR0 1.2%- 2. 8%, organic matter belongs to humus type. Minerals have mainly clay minerals and quartz, average mass fraction is 35% and 27% respectively. Pores in Longtan Formation shale have mainly developed organic matter pores, clay miner- al interslice pores and mineral dissolution pores. Micropore and small pore are extremely well developed and provided main pore specif- ic surface areas and volumes. Pore features in Longtan Formation are mainly controlled by sedimentary environment and diagenesis; clay mineral components and organic matter evolution have controlled nanopores development; deltaic swamp facies, mudilat facies and lagoon facies are all beneficial to Longtan Formation coal measures shale reservoir development sedimentary environments.