Microscopic pore structures and their primary controlling factors on the Lower Cretaceous Shuinan Shale in the Laiyang depressions were investigated using afield-emission scanning electron microscope,high pressure mercury intrusion,low-temperature nitrogen adsorption and carbon dioxide adsorption.Pore morphology and pore size distributions from macropores to micropores were successfully characterized.Combined with the geochemical parameters and mineral composition,the factors influencing the nanoscale pore structure were analyzed.The results indicate that the pores in the shale reservoirs are generally nanoscopic and can be classified into four types:organic pores,inter-particle pores,intra-particle pores and micro-fractures.The combination of the high pressure mercury intrusion,low-temperature nitrogen adsorption and carbon dioxide adsorption curves enable the pore size distributions for micro-,meso-,and macroporosity to be descripted.The results show that the pore connectivity is good,and the pore shapes are mainly slit shaped hole like parallel plates and bottle shaped holes of which the necks are narrow while the bodies are wide.The pore size distribution curve is multimodal,and the macropores,mesopores and micropores are all greatly developed,but the specific surface area is mainly composed of pores with pore size less than 100 nm,especially with that less than 2 nm.TOC has some positive effects on pores development,clay minerals mainly contribute to mesopores and micropores,and quartz and feldspar minerals are the main positive controlling factors of macropores.Carbonate minerals can cement and plug pores,resulting in large pores,mesopores and pore volumes are reduced,which have a negative effect on pores development.%为了研究莱阳凹陷陆相水南组页岩的孔隙发育特征,通过扫描电镜实验观察页岩孔隙微观形貌,高压压汞、低温液氮吸附及低温二氧化碳吸附实验对水南组页岩孔隙进行全尺度表征;并结合有机地化参数和矿物组成分析孔隙发育的控制因素.结果表明:扫描电镜镜下观察发现莱阳凹陷陆相页岩主要发育有机质孔、粒间孔、粒内孔及微裂隙等4种微观孔缝.高压压汞、低温液氮吸附及低温二氧化碳吸附实验联合表征发现孔隙连通性整体较好,孔隙形态以平行板状的狭缝形孔和细颈广体的墨水瓶形孔为主,孔径分布曲线呈多峰形态,大孔、中孔、微孔均发育较多,而比表面积主要由小于100 nm的孔隙,尤其以小于2 nm的微孔贡献为主.有机碳含量对孔隙发育有一定的控制作用,黏土矿物主要贡献中孔和微孔体积,石英、长石对大孔发育有积极的影响,而碳酸盐矿物会胶结堵塞孔隙,造成大孔、中孔及微孔体积均减小,对孔隙发育为消极的影响.
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