Functional-element constraint hydrocarbon distribution model and its application in the 3rd member of Dongying Formation, Nanpu Sag, Bohai Bay Basin, eastern China

The proposed functional-element constraint hydrocarbon distribution model consists of four basic functional elements including regional cap rock (C), favorable sedimentary facies (D), interfacial potential (P) and source kitchen (S). The combination of the four functional elements controls the formation and distribution of stratigraphic reservoirs in a basin. Regions with spatial and temporal overlaps of the four functional elements are the favorable zones for stratigraphic reservoirs. The geometric mean of the frequency of the four functional elements could indicate the possible distribution of stratigraphic reservoirs in a target zone. This paper describes constraint functions of the four functional elements on the hydrocarbon accumulations and their quantitative characterization. The hydrocarbon distribution model based on functional elements can predict development of stratigraphic reservoirs using T-CDPS, and the possibility for reservoir formation is determined by the index, Tcdps, in this paper. Based on the model, we have predicted seven areas of the Paleogene Ed3 in Nanpu Sag, which are favorable or moderately favorable for stratigraphic reservoir distribution. Among all the seven areas, five areas located in the Gaoshangpu structural belt, south of Laoyemiao structural belt and Nanpu I, II, V structural belt were favorable areas. Two moderately favorable areas were located in Nanpu III structural belt and Nanpu IV structural belt.