冀东油田老爷庙地区古近系东营组碎屑岩岩溶储层分布规律

Distribution of Clastic Karst Reservoirs of the Paleogene Dongying Formation in the Jidong Laoyemiao Oil Field

碳酸盐岩地层中的岩溶储层十分常见,但在碎屑岩地层研究中,却很少见到关于岩溶储层的报道。在对冀东油田老爷庙地区古近系东营组储层研究项目中,发现碎屑岩同样存在岩溶储层,而且其分布规律和控制因素与碳酸盐岩岩溶储层十分相似。东营组砂岩储层为三角洲—湖泊沉积,钙质胶结十分普遍。根据岩心和测井资料分析发现,砂岩岩溶储层发育在新近系和古近系之间的区域不整合面之下,孔隙主要是由砂岩中钙质胶结物溶蚀产生的。根据岩心和测井资料统计分析,不整合面之下砂岩岩溶储层带的厚度为150m左右。因此,对于钙质胶结的砂岩来说,不整合面之下是有利储层发育带。

Carbonate karst reservoir is very common, but no reports on clastic karst reservoir. The clastic karst reservoirs have been discovered in the Paleogene Dongying Formation in the Jidong Laoyemiao oil field in this study. The distribution and control factors of the clastic karst reservoir are very similar to those of the carbonate karst reservoir. The sedimentary facies of sandstone reservoir of the Dongying Formation is delta. Within sandstone reservoir, calcareous cementation is widespread. Based on the core and log data analysis, sandstone karst reservoir developed in a zone of 150 m in thickness below an unconformity between the Neogene and Paleogene strata. The porosity of the sandstone karst reservoir is mainly produced by the dissolution of calcareous cements. We suggest that a zone below unconformity is favorable to reservoir development for calcareous sandstone.