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孔隙是页岩层系是否具有生烃能力、储气能力和开采价值的主要标志.采用场发射扫描电镜对鄂西建始中二叠统孤峰组硅质页岩、泥质灰岩和炭质页岩3类岩石采取二次电子模式扫描,发现和分析了5大类9小类孔隙,即(1)絮凝作用孔隙;(2)有机质化石孔;(3)有机质碎片沥青孔;(4)黄铁矿粒间孔;(5)矿物颗粒晶间孔;(6)微型通道;(7)微裂缝;(8)钙质化石孔;(9)碎屑与围岩间孔.研究表明硅质页岩中发育较多的黄铁矿微球粒以及絮凝结构,有机质孔隙从纳米级至数微米;泥质灰岩中以矿物质孔隙为主,微裂缝比较发育,脆性矿物多;炭质页岩中存在大量蜂窝状孔洞和广泛分布的微裂缝,孔隙类型主要为有机质纳米孔.炭质页岩与传统储层孔隙特征具有很大差异,标志着油气储层纳米级孔隙研究的来临,是页岩气勘探最为有利的岩层.
Porosity is the main indicator of whether the shale formations have hydrocarbon generation ability, gas storage capacity and exploitation value.Using the field emission scanning electron microscope, the siliceous shale, argillaceous limestone and carbonaceous sheet of the Jufeng Formation in Jianshi Middle- Three types of rocks in the rocks were scanned using the secondary electron mode and five major categories of nine types of pores were discovered and analyzed, namely (1) flocculation pores; (2) organic fossil pores; (3) organic debris pitch pores; (4) yellow Intergranular pores of iron ore; (5) Intergranular pores of mineral grains; (6) Microchannels; (7) Microfissure; (8) Calcareous fossil pores; (9) There are many pyrite microspheres and flocculation structures in shale, and the pores of organic matter are from nanometer to several micrometers. The mineral limestone is the main component in shale limestone, with more micro-fissures and more brittle minerals. There are a large number of honeycomb-shaped pores and widely distributed microcracks in the rock, and the pore types are mainly organic nanopores.The carbonaceous shale has great difference with the pore characteristics of the traditional reservoirs, which indicates that the research of nanoscale pores in oil and gas reservoirs is coming Shale gas exploration is the most favorable rock formation.