高尚堡深层低阻油层的地质成因

高尚堡深层复杂的地质条件导致淡地层水环境下低阻油层与典型的中、高阻油层间互发育。以岩石物理学研究为基础，结合沉积特征、成岩作用和成藏特点，对高尚堡深层低阻油层的地质成因研究表明，其低阻油层的形成受沉积、成岩、油藏特点的综合影响，黏土矿物附加导电性、复杂孔隙结构是低阻油层形成的微观机理。受陡坡带浅水型混源扇三角洲前缘沉积特征的影响，在高尚堡深层形成薄互层型和弱水动力环境下泥质含量偏高的低阻油层。中成岩阶段A期的成岩作用导致发育复杂孔隙结构成因、黏土矿物附加导电型低阻储层；岩性圈闭和深层成岩作用的非均质性导致油砂体小，油气成藏构造幅度低，且当油层孔隙结构变差或泥质含量高时，含油饱和度降低，也可形成低阻油层；构造幅度低、油水分异作用差，在油水过渡区域也易形成低阻油层。

Geologic origin of low-resistivity layers in deep reservoir of Gaoshangpu Oilfield

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.