济阳坳陷埕东地区新近系馆上段下部三角洲沉积特征

Delta sedimentation of upper Guantao Formation of the Neogene in Chengdong area of Jiyang Depression

根据泥岩颜色、古生物化石、沉积构造、岩石类型、颗粒结构和砂体形态等沉积相标志,证实了济阳坳陷埕东地区新近系馆上段下部存在湖泊三角洲沉积,而不是单纯的河流相沉积。通过分析该区馆上段下部沉积相特征发现,在馆上段的三角洲沉积中发育水下分流河道、河口坝、远砂坝、席状砂等微相和前三角洲亚相。该区沉积相与油气分布关系分析表明,河口坝、远砂坝和席状砂微相是最有利的油气聚集带。

On the basis of integrated analysis of shale color,fossil assemblage,sedimentary structures,lithological type,grain pattern and sand body morphology,it is proved that there are lake delta sediments apart from fluvial facies deposited in the upper Guantao Formation of Neogene in Chengdong area of Jiyang Depression.After analysis of sedimentary facies characteristics in the lower part of upper Guantao Formation,the deltaic facies in the upper Guantao Formation can be subdivided into submerged distributary channel,mouth bar,distal bar,sand sheet and some other microfacies and prodelta intrafacies.Relationship between sedimentary facies and hydrocarbon distribution shows that most favorable oil and gas accumulation zones occur in the mouth bar,distal bar and sand sheet.