IDENTIFICATION METHODS FOR EFFICIENT SOURCE ROCKS

For a long time, the source rocks from 1?000 to 1?500 meters in thickness were thought to be the efficient source rock in Donying depression, because the content of organic carbon in the dark mudstones is over 0.5 percent, which has been the reasonable mark for identifying the efficient source rock. But the precise oil source comparison shows that the thickness of the source rocks is impossible up to 1?000 meters or more. The source rocks containing organic carbon of 1.5 percent in the upper Sha 4 and the lower Sha 3 subsections mainly attributed to hydrocarbon reservoirs and controlled the formation of millions tons of oil gas fields in Dongying depression. Therefore, the minimum organic carbon content of the efficient source rocks should be determined according to the actual condition in that area. Firstly, the efficient source rock layers may be identified with the oil source comparison method. Then the evaluation standard of the efficient source rocks can be obtained with the combination of sedimentary and geochemistry characteristics of the different layers. The rid of intermediate layer in the non source rock and kinds of parameters about source rocks can be achieved by using logging method. Finally, the identification and evaluation of the efficient source rocks may be finished.