The Study on the Palaeogene Lacustrine Reefs in Jiyang Sag，Eastern Shandong Province

Key words: 
• Jiyang Sag /
• reef /
• lithology /
• rock /
• reservoir

Abstract: The reefs, mainly constructed by algae and with high production reservoir for oil and gas, are developed in several areas of Jiyang Sag in the form of composite deposition, that is, reef core, forereef and back reef. Taking into account of the biogenic components, the algal dolomite, the main component of algal reefs, consisted of Cladosiphonia sinensis, Serpula shandongensis etc., and be of favorable storage capability. Based on the lithological characteristics of reef rocks, the reef types can be divided into algal reefs, algal reef mounds and algal biostromes, among which the algal reefs, are of the best reservoir property. Dolomitization, consortium cementation, atmosphere seepage corrosion and deep embedding effect have great influence on the property of reef reservoir. The reef reservoirs are developed mainly in the neighboring structural platform or brim, according to the matching relation of structure, lithology and stratum, reef reservoirs can be divided into reef stratum, fault blocklithology and lithology types.