HD4油田东河砂岩油层的岩石学特征

为了解塔里木盆地HD4油田东河砂岩岩石学特征对油气储集的影响,研究其矿物组合特征、孔隙结构特征。借助偏光显微镜、扫描电子显微镜观察岩石、铸体薄片及岩石样品,利用X-衍射仪确定黏土矿物组合及其含量。结果表明:该油层岩性主要为岩屑长石砂岩;该地区距物源远,母岩为沉积变质岩;黏土矿物组合为绿泥石+伊利石+高岭石;孔隙类型以最适合油气富集的原生粒间孔为主,方解石、硬石膏等胶结物与次生石英等充填了部分孔隙,总体上油层孔隙较发育;黏土矿物组合对石油的开采影响较小。HD4油田东河砂岩油层是良好的石油储集层。该结果对油田油气预测及开发具有参考价值。

Petrological characteristics of Donghe sandstone reservoir in HD4 oilfield

This paper is concerned with studying the mineral composition and pore structure characteristics for a deeper insight into the influence of petrological characteristics of Donghe sandstone in the tarim basin on oil and gas reservoir. This study involves observing the rock thin sections and casting thin sections and rock samples using polarizing microscope and scanning electron microscope; detecting the combination of the clay minerals and their content using the X-ray diffractometer. The study finds that the area far away from the source is characterized by the following occurrences： the lithology of the reservoir consists mainly of lithic feldspar-porphyry sandstone; original rocks occur as sedimentary metamorphic rocks and clay minerals are composed of the combination of chlorite,illite,and kaolinite; pore types are dominated by interparticle pores suitable for oil and gas enrichment,allowing some pores to be filled with calcite,shale and anhydrite and thus leaving the pores of the sandstone reservoir relatively well developed; and the clay mineral groups have such a small influence on the exploitation of oil that the Donghe sandstone in HD4 oilfield is a better oil reservoir. This result may be of reference value to the oil and gas prediction and development.