定边地区富县组油气成藏条件研究

Oil And Gas Accumulation Conditions of Fuxian Formation in Dingbian Area

在定边地区富县组地层的构造特征、沉积相分布及砂体展布的分析基础上,从油源、油气运移路径及盖层等方面分析了富县组的油气成藏条件.分析认为:上三叠统延长组的深湖相泥岩为富县组提供油源,油气通过网络状的砂体向上运移,在构造和岩性圈闭中聚集;岩性圈闭是富县组油气成藏的主控因素;研究区沉积微相由西向东从砾砂质河道渐变为洪泛平原沉积,砂体厚度减薄,直至尖灭;定边东部地区较高,微幅构造发育,有利于形成上倾尖灭性岩性油气藏及岩性-构造油气藏.

Based on the analysis of the structural characteristics,the distribution of sedimentary facies and the spread of sand body of Fuxian Formation in Dingbian area;this paper analyses the oil and gas accumulation conditions of Fuxian Formation from the oil source,oil and gas migration path and cover etc..It is concluded that： the deep lacustrine mudstones of Upper Triassic provides oil sources for Fuxian Formation,oil and gas migrate upward through netlike sand and accumulate in structural and lithologic traps.Lithologic traps as the main controlling factors of the oil and gas accumulation of Fuxian Formation.The Microfacies of the studied area have a gradient of the sandy river gravel to floodplain from east to west,the thickness of sand body decreases,until the tip off.Because the east of Dingbian area is higher and develop swell structural,form updip pinch lithology reservoir and lithology-tectonic reservoir in the east of the studied area.