Abstract: Raoyang sag is a typical continental rifted sag richest in hydrocarbons in Jizhong depression and has good geological conditions for forming lithologic-stratigraphic reservoirs. Researches indicate that the forming and distribution of lithologic-stratigraphic reservoirs in this sag are controlled by four control factors, among which the structural setting and paleogeomorphology control extension of sedimentary system and sand body; the basement of carbonate platform and strong tilted block movement in Cenozoic and the sedimentary-reservoir facies belt and trough rich-in oil control definitively the distribution and abundance of lithologic-stratigraphic reservoirs. The reservoirforming patterns of lithologic-stratigraphic reservoirs are established on the basis of reservoir-forming characters of steep belt, trough belt, central buried-hill structural belt and slope belt within the sag.

Key words: Raoyang sag, lithologic-stratigraphic reservoir, control factor, reservoir-forming pattern, hydrocarbon accumulation pattern