摘要
在宏观地质特征研究的基础上,依据岩芯观察,结合铸体、包裹体、荧光和阴极发光等各类薄片鉴定及粒度分析、激光共聚焦、恒速压汞、核磁共振、FIB、扫描电镜等测试手段,对长7段致密砂岩进行了多角度的储层非均质性研究和分类量化评价。结果表明,沉积微相造成了储层原始的非均质性,前三角洲浊积复合砂体是储层有利发育区;后期成岩改造增强了储层的非均质性,持续的压实作用、多期次的钙质和硅质胶结交替发生,导致储层致密化,溶蚀、破裂作用阶段性改善了储层物性,形成致密化背景上有效储层的局部发育;在储层非均质性成因机理分析的基础上,提取岩石成熟度、成岩系数和裂缝综合指数等关键参数实现了储层的分类量化评价,指出研究区东北部A区为Ⅰ类储层发育区。
On the basis of macroscopic geological characteristics,integrating core observation as well as measuring methods including thin section identification( casting,inclusion,fluorescent detection and cathodoluminescence),particle size analysis,laser confocal microscopy,rate-controlled mercury penetration,nuclear magnetic resonance,FIB,scanning electron microscopy etc.,the multi-angle reservoir heterogeneity study and the quantitative evaluation of the Chang 7 tight sandstone reservoir were carried out. The results show that the original heterogeneity of the reservoir was caused by sedimentary microfacies,and the prodelta turbidite composite sand body is a favorable reservoir development area. The later stage of diagenesis enhanced the heterogeneity of the reservoir. Moreover,the continuous compaction,and multistage alternation of calcareous cementation and siliceous cementation resulted in reservoir densification. However,dissolution and fracturing improved the reservoir physical properties in certain stages,which resulted in the local development of effective reservoirs on the tight background. Integratedwith the analysis of the mechanism of reservoir heterogeneity,the key parameters such as rock maturity,diagenetic coefficient and fracture comprehensive index were extracted to conduct a classified and quantitative reservoir evaluation. It is suggested that the northeast A zone is the Class I favorable reservoir. This evaluation would provide guidance to the selection of exploration targets in tight sandstones.
出处
《世界地质》
CAS
2017年第4期1170-1180,共11页
World Geology
基金
国家科技重大专项(2016ZX05002-006-003)资助
关键词
鄂尔多斯盆地南部
长7致密砂岩
储层非均质性
储层评价
Southern Ordos Basin
Chang-7 tight sandstone
reservoir heterogeneity
reservoir evaluation
