Abstract:

When the oilfield major reservoirs are in the high water period, replacing the major reservoirs by the non-major reservoirs becomes an inevitable trend. The reservoirs of delta frontal sub-faces are taken as non-major reservoirs because of strong non-homogeneous. To improve reserve’s producing degree, it is necessary to describe fine reservoir heterogeneity, and to ascertain the law of residual oil distribution, then to guide the oilfield development adjustment plan. In this paper, the characteristics of reservoir of delta frontal sub-faces of PI Formation in the south of Xingshugang are studied with the data of dense well pattern and rock-mineral identification. The delta frontal sub-faces can be divided into lobate delta frontal subfaces, branched delta frontal sub-faces and sheeted delta frontal sub-faces. The genetic types of sand bodies in different sedimentary envivonments are analyzed in detail, and the distribution and space-matching relationship of different sand bodies are studied. The micro-pore structure type is studied on the base of the thin section analysis,so the reservoir heterogeneity is studied including plane heterogeneity,interlayer heterogeneity,in-layer heterogeneity and microcosmic characteristic. The influence of reservoir heterogeneity remained oil is analysed, and enrichment position of remained oil in reservoir of different delta frontal sub-faces is pointed out at last.

Key words: delta front, reservoir heterogeneity, micro-pore structure, the south of Xingshugang