摘要
通过大量砂岩样品铸体薄片、扫描电镜及阴极发光等资料分析,华庆地区长9储层砂岩主要成岩作用有压实压溶作用、胶结作用及溶蚀作用等。其中压实压溶作用、绿泥石膜、浊沸石、硅质等胶结作用使该区长9砂岩物性变差,而溶蚀作用,尤其是长石和浊沸石的溶蚀使致密储层的储渗性能得到改善,局部形成相对高孔高渗储层。华庆地区长9砂岩中存在浊沸石胶结物,而长9以上延长组层位没有浊沸石胶结物,研究认为和该区长9储集砂岩长石碎屑含量高,水下分流河道砂体沉积厚度大、埋藏较深有关系。长9砂岩孔隙类型以粒间孔为主,长石溶孔、浊沸石溶孔次之。根据不同区域主要成岩作用类型、胶结物含量及孔隙类型,将该区长9砂岩划分为六种成岩相,分别为压实压溶相、绿泥石膜-粒间孔相、长石溶蚀相、浊沸石溶蚀相、绿泥石膜-浊沸石胶结相以及铁方解石胶结相。其中长石溶蚀相和浊沸石溶蚀相为有利成岩相,主要分布于水下分流河道的前端,靠近湖泊水体较深的位置。有利成岩相形成的相对高孔、高渗储层区带是长9下步勘探的重要目标区。
Through the analysis of large number of sandstone samples＇ cast body sheet,scanning electron and cathodoluminescence data,the main diagenesis of Chang 9 sandstones include mechanical-chemical compaction,cementation and dissolution.The mechanical-chemical compaction,chlorite coating,laumontite,siliceous cementation,etc caused the loss of porosity of Chang 9 sandstones.Whereas the dissolution,especially the feldspar and laumontite dissolution improved reservoir quality of dense reservoir,forming local relatively high porosity and permeability reservoirs.Chang 9 sandstones in Huaqing area contain laumontite cement,but there are no laumontite cement above of Chang 9 layer of Yanchang Formation.Studies indicate that because of three factors which are high content of feldspar debris in Chang 9 sandstones,huge thick sand body of underwater distributary channel deposition,and deeper buried depth.The main pore type of Chang 9 sandstones is intergranular pore,and feldspar dissolution pore and laumonite dissolution pore take second place.According to the main diagenesis types,content of cement and pore types in different area,Chang 9 sandstones in Huaqing area are divided into six diagenetic facies,and these are mechanical-chemical compaction facies,chlorite coating-intergranular pore facies,feldspar dissolution facies,laumonite dissolution facies,chlorite coating-laumonite cementation facies and ferrocalcite cementation facies.The feldspar dissolution facies and laumontite dissolution facies are favorable diagenetic facies,which mainly distribute in the front end of the underwater distributary channel,near the deep water of the lake.The relatively high porosity and permeability reservoirs which are formed by favorable diagenetic facies is the important target areas for the next step prospecting.
出处
《西安科技大学学报》
CAS
2013年第3期298-306,共9页
Journal of Xi’an University of Science and Technology
