Study On Heterogeneity Characteristics And Recovering The Palaeoproductivity Of Paleogene Source Rocks In Dongying Sag

Heterogeneity analysis of source rocks is a present research hotspot, because it not only the key to evaluate the hydrocarbon generation potential of a basin, but also fundamentally affects the paleoproductivity of source rocks. In view of the roughly analysis of heterogeneity characteristics, unclear research of paleoproductivity level and lack of controlling factor analysis, the heterogeneity characteristics of Paleogene source rocks in Dongying sag is analysed meticulously, the paleoproductivity of various sedimentary period is recovered quantitatively, and its controlling factors are discussed by using the method of geochemistry and modern test technology. The results are as follows.(1) Paleogene source rocks in Dongying sag have significant macroscopic and micro heterogeneity. Its macroscopic heterogeneity is mainly manifested in the longitudinal scale and the lateral scale. Lithologic features of source rocks in different depth and systems tracts reflect the longitudinal macroscopic heterogeneity, whereas lithologic features of source rocks in different subsags and sedimentary facies belts embody the lateral macroscopic heterogeneity. Moreover, its micro heterogeneity is mainly manifested in the microscopic sedimentary structure, organic carbon content, biomakers, microscopic fluorescence and pollen characteristics of source rocks.(2) Quantitative calculation of paleoproductivity is in sequence of Es4 s > Es3 x > Es3 z > Es1> Es3 s > Es4 x > Es2 > Ek2 > Ek1. According to the fact that exploration targets in Dongying sag gradually shifts to the deep layer and combining with the paleoproductivity and heterogeneity characteristics of deep source rocks, Kong 2 member can be the next exploration target.(3) Paleoproductivity level and heterogeneity characteristics of Paleogene source rocks in Dongying sag are controlled by the water size, climatic conditions, algal blooming degrees and water preservation conditions.This study is not only of certain theoretical significance to the hydrocarbon resource potential evaluation of continental rift basin in eastern China, but also can further guide the deep hydrocarbon exploration in Dongying sag.