Abstract:

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.

Key words: Jidong Laoyemiao oil field, Dongying Formation, clastic karst reservoirs, sandstone