吴起地区延长组长6单砂体条带状含油分布特征及其成因

Characteristics and genesis of banding oil distribution in single sandstone of Yanchang formation Chang-6 reservoir in Wuqi area

储层非均质性对油气田的勘探和开发效果影响较大。结合岩心观察、薄片资料、扫描电镜、物性、录井等资料,对吴起地区长6油层组条带状含油分布特征进行研究。结果表明:层内非均质和微观非均质是造成单砂体条带状含油分布的主要原因,储层韵律段的粗粒部分含油性较好,层理密度大则含油性差;钙质夹层越发育的储层,含油性越差;胶结作用使孔隙结构复杂化,造成储层含油性不均;单砂体条带状含油分布形成不同的油水系统,导致油藏含有多个油水界面。研究成果对研究区进一步勘探、开发具有一定的指导意义。

The reservoir anisotropy has an important effect on the exploration and development of oil and gas fields. By combination of the core observation, thin section, scanning electron microscope, reservoir physical property and logging, the banding oil distribu- tion characteristics of Chang-6 reservoir in Yanchang formation of Wuqi area were studied. The results showed that the inner layer heterogeneity and micro-heterogeneity are the primary causes of banding oil distribution. The coarse grains of rhythm layer have higher oil potentials. The denser of beddings and calcareous interbeds developed have poor oil potentials. The cementation further complicates pore structure and causes uneven distribution of reservoir oil-bearing. The banding oil distribution in single sandstone form the different oil-water system and lead to the multiple oil and water interface of reservoir. The research has guiding signifi- cance for the further exploration and development of the resources in this area.