鄂尔多斯盆地陇东地区长7致密油成藏条件与主控因素

The Reservoir Formation and Main controlling Factors of Tight Oil of Chang 7 in Longdong Area of Erdos Basin

基于大量钻井、分层、分析化验等基础资料,结合岩心观察及薄片鉴定,通过地质和地球化学相结合的方法对鄂尔多斯盆地陇东地区长7油层组的地质条件、烃源岩条件、储层条件、储盖条件、运移通道条件等方面进行了详细分析,发现陇东地区长7油层组油藏为典型的准连续型致密砂岩油藏.研究区内浊流沉积砂体发育,丰富的油源及垂直的微裂缝为油气的运移、聚集成藏提供了良好的条件,其中孔隙发育、物性好的储层为油气富集区.鼻状构造背景对陇东地区长7致密油的富集作用不明显,而主要取决于源储一体或源储紧邻的近源环境、半深湖—深湖相及砂质碎屑流大面积连续分布的地质基础及优质储层对油藏的控制作用.

In this paper, based on massive basic data of well drilling, layering and experimental analysis, combined with the core observation and thin section identification, by the combination method of geology and geochemistry, the geological conditions, source rock conditions, reser- voir conditions, storing-cover conditions and migration pathway conditions of Chang 7 formation in Longdong area of Erdos basin are analyzed in detail. Data shows that the Chang 7 oil-bearing formation in Longdong area is a typical quasi-continuous tight sandstone reservoir. The turbidity deposit sandbodies are happended in the study area. Abundant oil source and the vertical micro fractures provide favorable conditions for migration and accumulation of oil and gas, and the re- gion with good porosity and physical property is a gas enrichment area. The Chang 7 tight oil accumulation is not controlled by the nose-shaped tectonic background, but source-reservoir in- tegration or near source-reservoir environment, and basic geology of continuous distributionsemi-deep to deep lake face sandy debris flow in large scale and high quality reservoirs.