山东济阳石炭-二叠系煤成气储层沉积研究

在建立层序地层格架的基础上进行煤成气储层沉积学研究。储集在二叠系砂岩(属于致密砂岩)储层内的煤成气藏成为重要的天然气藏。济阳地区上石盒子组万山段、奎山段和孝妇河段,发育河流相、湖泊滨岸相为主要特色的砂质沉积,是煤成气主要储集层。主要储层沉积相为河道滞留与边滩组成的河道充填。煤成气储集空间主要是次生孔隙。本区石炭-二叠系砂岩成岩作用强烈,原生粒间孔保存较少,大部分的粒间孔隙是由于后期溶蚀作用形成的。这种次生的粒间孔隙充填在粒间孔隙之间的杂基或胶结物后期经溶蚀作用形成。二叠系气藏的直接盖层主要是下石盒子组的河漫相、山西组及太原组的三角洲平原和湖沼相沉积的泥岩、煤和炭质泥岩。

Sedimentary Study on Coal-formed Gas Reservoir of Permo-Carboniferous System in Jiyang Area, Shandong

This paper studies coal gas reservoir sedimentology on the basis of establishing sequence stratigraphy framework.Coal gas pool stored in sandstone(compact sandstone) reservoir of Permian system becomes important natural gas pool.In Jiyang,sandy deposit,which is mainly featured by river facies and lacustrine coastal faces,develops in Wanshan,Kuishan and Xiaofu Member of the Upper Shihezi Formation.And these three members become the main reservoir of coal gas.The main reservoir sedimentary facies is channel fill formed by channel detention and marginal bank.The main reservoir space of coal gas is induced porosity.In this area sandstone diagenesis of Carbonic-Permian system is very strong and there are less protosomatic intergmular pores.Most intergranular pore space is shaped after corrosion.Matrix or cement filled in intergranular pore space suffered from after-corrosionand then formed such heterogeneousintergranular pore space.The direct cap rock of gas pool of Permian system is mainly fluvial facies of Lower Shihezi Formation,delta plain of Shanxi Formation and Taiyuan Formation and mudstone,coal and carbargilite of limnological facies.