Characteristics of Petroleum Geology and Prediction of Favorable Areas in Jiufotang Formation, Kazuo Basin

Abstract

Through the research on actual measurement 106km geological profile, the hydrocarbon source rocks mainly develop the third member of Jiufotang formation, followed by the second member. There are five distribution areas where have been divided hydrocarbon source rocks thickness is more than 400m in study area. Among them, Jiufotang area has the greatest sedimentary thickness of hydrocarbon source rocks, while Siguanyingzi-Sanjiazi area has the largest area where hydrocarbon source rocks are more than 400m. Oil shale is good hydrocarbon source rock, while dark gray and black gray mudstone (or shale) are relatively poor. The fan delta front subaqueous distributary channel and mouth bar are well-developed in basin’s fault zone and also the important favorable reservoir, followed by braided delta front mouth bar, subaqueous distributary channel and distal bar developing in northwestern area of the basin. There are four forms of source-reservoir-cap combination: (1) hydrocarbon source rock in the above layer and reservoir in the below layer; (2) hydrocarbon source rock and reservoir in the same layer; (3) normal form; (4) fingerlike intersection. The combination of fingerlike intersection is the most important forms in study area. Fan delta facies next to lacustrine facies is favorable exploration area.