Oil-gas bearing systems of the Sha-III and the upper Sha-IV member in the dongying depression

摘要

In this paper all source rocks, reservoirs and covers in the Dongying depression are taken as the Dongying depression oil-gas bearing system, while hydrocarbon source rocks in the Sha-III and the Sha-IV Member are taken as an oil-gas bearing subsystem. The evolution history of the Dongying depression is given by buried curves. Two stages of oil-forming are recognized and the critical time of 2 Ma is determined. Also it is pointed out that The SPI values of hydrocarbon source rocks are a relation to the filling conditions of oil-gas pools.