龙凤山气田营城组浊沸石胶结物对储层的控制机理

摘要

浊沸石作为富火山碎屑储层中重要的胶结物,对储层演化至关重要.结合铸体薄片、CT扫描、压汞实验及X衍射等资料,对龙凤山气田营城组砂岩中浊沸石的形成机理和分布规律进行研究.结果表明:1)营城组浊沸石主要受水体性质控制,在平面上具有分带性,主要分布在水体碱性较强的扇三角洲外前缘;2)浊沸石胶结砂岩压实较弱,中成岩早期有机质生烃过程中所产生的有机酸溶蚀后,形成大量胶结物内溶蚀孔;3)浊沸石溶蚀形成的储层具有较好的物性,覆压条件下其渗透率下降幅度相对较低,浊沸石胶结-溶蚀的扇三角洲外前缘是优质储层发育区.%Being the important cement in rich volcanic clastic reservoirs,laumontite is significant to reservoir evolution.By means of casting thin section,CT scan,mercury injection test and X diffraction,the formation mechanism and distribution law of laumontite in sandstone of Yingcheng Formation in Longfengshan gas field are studied.The results show that the laumontite is mainly controlled by the property of water and has an obvious zoning features in plane,mainly distributes in the outer edge of the fan delta with strong alkaline water,with weak laumontite sandstone compaction,organic acids that expelled in the process of thermal maturation of kerogen dissolved laumontite cement and formed a large number of pores in the cementation;the reservoir formed by the dissolution of laumontite has good physical properties and low permeability decrease under the confining stress,and high quality reservoirs developed in the distal part of delta front are laumontite-dissolved sandstones.