Abstract: Clegu-20 buried hill is am anticline-like structure with NNE axial trend, Chengnan and Eraijie faults at both sides and developed secondary fauls which cut it into several blocks. It consists of Archaeozoic and Paleozoic strata in which Cambrian and Ordovician arc dominal-ed by limestone. The tectonism and weathering make it become a good reservoir. Chegu-20 buried hill was formed in early Kongdian fornation of Pauleogene. Sha 3 meuber of Choxi sag adjacent to Chegu-20 buried hill is a favorable source-migration-trap system for hydtocarbon accumula-tion with developed source rocks, abundant vil sources and source sag-faulting-buried hill configuration. It is suggested that Chegu-20 buricd hill might be an advantageous area for oil-gas prospecting.

Key words: Shengli oilfield, buried hill, reservoir, fauling, origin