Petroleum geological characteristics and hydrocarbon accumulation models of the Kenli A Oilfield, Bohai Bay Basin

On the basis of structural characteristics and sedimentary background of the Bohai Bay Basin, the Kenli A Oilfield is selected as the case to reveal the oil and gas accumulation conditions. The data of drilling, logging, chemical analysis and testing are integrated for the purpose. It is noticed that high quality source rocks are widely distributed in the middle of the third member and the fourth member of the Shahejie Formation in both the north and south subsags of Laizhou Bay Depression, and the oil supply is sufficient. Oil source faults, permeable sand bodies and unconformities form an excellent oil and gas transmission system, and the oil and gas enrichment horizon, which is shallow in the west and deep in the east. Based on the observation mentioned above, three types of hydrocarbon accumulation models are summarized by this paper: the “lateral”near-source accumulations in the eastern part of the structure, where oil and gas accumulated in the Shahejie Formation of Paleogene and the buried hill of the Mesozoic; the“Stepped”far-source accumulations in the middle of the structure, and the far-source“Net-blanket”accumulations in the western part of the structure in the Neogene Guantao Formation.