Architecture and water flooding distribution of the delta front reservoir in the Suizhong Oilfield, Northern Bohai Bay Basin, North China

Suizhong Oilfield is the important offshore oilfield in North China, which is in the middle-late development stage. The water-cut in Suizhong Oilfield is above 70%, and water content is moving upward quickly. Oil reservoir in... [ view full abstract ]

Suizhong Oilfield is the important offshore oilfield in North China, which is in the middle-late development stage. The water-cut in Suizhong Oilfield is above 70%, and water content is moving upward quickly. Oil reservoir in research area is high porosity and permeability reservoir with weak diagenesis, so water flooding distribution is mainly controlled by sedimentation. Based on cores, outcrops, well logging, seismic and dynamic data, this paper researches architecture characteristics, quantitatively analyses distribution and scale of the single mouth bar and foreset bed of Lower Dongyin Formation, palaeogene in Suizhong Oilfield, Northern Bohai Bay Basin, North China. On this basis, by qualitatively analyzing of geological factors and quantitatively analyzing of numerical simulation results, water flooding distribution model is researched. Followings are the main results and conclusions.(1) Three architectural elements are distinguished as distributary channels, mouth bars and beach sands in study area. The distribution of the mouth bar has thin sheet and thick belt-like. Foreset bed in the mouth bar is weakly continuous whose angle is 0.4~1.0o. And the distribution of foreset bed is foreset pattern on source direction and is arch pattern on vertical source direction. (2) Different scale of seepage barrier has different effect on water flooding distribution. Vertical permeability barrier between mouth bars could lead vertical stratified water flooding model. And lateral permeability barrier between single mouth bars could make injection-production relation imperfect. Foreset interlayer in mouth bar could lead the lower flooding degree in lower prograding wedge on source direction, but also could lead water flooding evenly on vertical source direction. (3) The architectural element with different reservoir quality controls the water flooded reservoir distribution laws. The water flooding degree of distributary channel and main bar is strong, and the distribution of it is ribbon, lobate or flake-like in the plane. It’s conducive to adjustment of oilfield development plan by researching water flooding distribution.