关键词: 高尚堡油田, 深层, 低阻油层, 地质成因, 黏土矿物, 孔隙结构

Abstract:

The complicated geology conditions in the deep reservoir of Gaoshangpu Oilfield resulted in the alternation emergence of the low-resistivity layers with the typical middle and high-resistivity layers in the fresh water environment. On the basis of sediment, diagenesis and reservoir characteristics, the formation of low-resistivity layers in the deep reservoir of Gaoshangpu Oilfield was analysed, the result showed that it was integrative influenced by the deposition, diagenesis and property of oil reservoirs. The low-resistance layers were resulted from the additive conductivity of clay mineral and the complicated pore structure. The multi-provenance fan-delta sedimentary characteristics in the shallow water zone of steep slope led to the thin sand-shale interbedding and high-content shale and low-resistivity layers in the deep reservoirs under the weak water dynamics environment. The diagenesis in the A period of middle diagenetic-stage resulted in the development of low-resistivity complicated pore structures and additive conductivity of clay mineral. The lithology trap and diagenesis heterogeneity of deep reservoirs resulted in the small oil sand body and poor hydrocarbon reservoir. Those factors also resulted in the reduction of oil saturation and formation of the low-resistivity layers when the porous structure was poor or the silt content was high. The low-resistivity layer was easily formed in the oil-water transition zone when the attribution of structure was low and differentiation of oil and water was poor.

Key words: Gaoshangpu Oilfield, deep reservoir, low-resistivity layers, geologic origin, clay mineral, pore structure