RESERVOIR CHARACTERISTICS AND INFLUENTIAL FACTORS IN THE EASTERN DEPRESSION OF THE NORTH YELLOW SEA BASIN

Mesozoic and Cenozoic deposits occur widely in the Eastern Depression of the North Yellow Sea Basin. The Jurassic and Cretaceous are the main targets for hydrocarbon reservoirs. Based on the data from the surveys recently conducted for oil and gas resources, and together with the data from regional geological surveys in the region, we studied the characteristics of the Cretaceous reservoirs in this paper. Our results indicate that the reservoirs in the study area are low or very low in both porosity and permeability. The storage spaces are mainly provided by secondary interstitial pores formed by dissolution and fracturing. The deposits have suffered from various types of diagenesis, such as compaction, cementation, replacement, and dissolution. The strong compaction and cementation obviously play a great role in control over the poor reservoir properties, but the weak dissolution and fracturing may improve the reservoir properties to some extent.