Abstract:

Dongying depression is a halfgraben-like rift lake basin with the characteristics of steep slope developed in the north while gentle slope in the south during Shahejie period. The depression can be divided into four structural zones, i.e. steep slope zone, gentle slope zone, sag zone and build-up zone. There are various diageneses developed in the Shahejie Formation, including compaction, pressolution, solution and cementation, and so on. Diagenses developed in different structural belts are always different. Compaction during earlier period can impress more effect on the reservoirs than that during later period. The amounts of carbonate cements and clays vary in different structural belts. The solution depth differs in various structural belts, thus the depth with secondary porosity occurrence is different obviously. The diagenetic difference of various structural zones can create different diagenetic facies belts with unique characteristics. Therefore, it is quite important theoretically and practically to study such differences among various structural belts for lithological oil and gas pool exploration

Key words: Dongying depression, halfgraben-like rift lake basin, Shahejie Formation, structural belt, diagenesis