鄂尔多斯盆地富县地区长8段油气成藏主控因素研究

Research on main controlling factors of oil and gas accumulation in Chang 8 member in Fuxian area,Ordos Basin

近年来,富县地区延长组长8段油层组发现了工业油流井,但平面分布不均,具有点状含油的特点,勘探开发总体显示出该区具有多层位含油、局部层位富集的特征,但油水分布主控因素与富集规律尚不清楚,制约了该区下组合油气的勘探开发,为此,基于钻井和生产资料,分析了研究区长8段油层组的油藏类型、主控因素和成藏模式,研究表明,区内长8段油藏类型主要为上倾尖灭岩性油藏、透镜状岩性油藏和致密层遮挡岩性油藏;油气成藏受烃源岩、储层物性、砂体厚度、局部构造共同控制;长8段油气成藏模式为典型的三明治型,有利于致密油的形成。

In recent years,industrial oil flow wells have been found in Chang 8 member of Yanchang formation in Fuxian area.However,uneven horizontal distribution is characterized by spot oil bearing.Exploration and development generally show that this area is characterized by multilayer oil bearing and local layer enrichment.However,the main controlling factors and enrichment rules of oil and water distribution are still unclear,which restricts the exploration and development of combined oil and gas in this area.Based on drilling and production data,the reservoir types,main controlling factors and reservoir-forming modes of Chang 8 reservoir group in the study area are analyzed.The research shows that the reservoir types of Chang 8 member are mainly updip pinch-out lithologic reservoir,lenticular lithologic reservoir and tight layer occlusion lithologic reservoir.Hydrocarbon accumulation is controlled by source rock,reservoir physical property,sand body thickness and local structure.The reservoir formation pattern of Chang 8 member is typical sandwich type,which is conducive to the formation of tight oil.