为探讨成岩相的定量划分与识别方法,利用铸体薄片、扫描电镜、X射线衍射、压汞和测井资料,对鄂尔多斯盆地薛岔地区长6储集层进行了成岩作用强度参数定量评价和成岩相测井识别。结果表明,长6储集层经历了中等-强压实作用、弱-中等胶结作用、弱-中等溶解作用。根据成岩作用强度、胶结物类型、孔隙类型及其发育程度,划分出5种成岩相,不同成岩相的自然伽马、声波时差和电阻率测井响应差异大。成岩相与沉积微相表现出良好的对应关系,分布于水下分流河道砂体的中等压实绿泥石胶结-粒间孔相,孔隙发育程度高,物性好,排驱压力低、大孔喉含量高,是最有利的成岩相;中等压实伊利石胶结-溶蚀孔相和中等压实硅质胶结相次之。
In order to probe the quantitative classification and identification method of diagenetic facies,the quantitative evaluation of diagenesis intensity parameters and the logging identification of diagenetic facies of the Chang6 Reservoir in the Xuecha area,Ordos Basin have been carried out in this paper by using casting section,SEM,XRD,mercury injection and logging data. Results show that the diagenetic facies in the Chang 6 Reservoir had experienced the medium-strong compaction,weak-medium cementation,and weak-medium dissolution. Five diagenetic facies have been classified based on their diagenetic intensity,cement type,and pore type and development degree. There are obviously different responses on natural gamma,acoustic time and resistivity logging among various diagenetic facies in the area. There is a good correlation between diagenetic facies and sedimentary microfacies. The moderately compacted,chlorite cemented and intergranular pored diagenetic facies,which is distributed in sandy sediments beneath the river bed,is the most favorable diagenetic facies because of the high development degree of porosity,good physical properties,low expulsion pressure,high content of big pore throat. The moderately compacted,illite cementated,dissolution pored facies and the moderately compacted,siliceous cemented facies are the secondary favorable diagenetic facies.