东濮凹陷古近系的低位三角洲沉积

Lowstand delta sedimentary of Paleogene in Dongpu sag

在对东濮凹陷古近系盐岩成因重新认识的基础上 ,发现了湖平面频繁变化的标志 ,估算其湖平面变化频率为 10 0 0次/Ma ,认为湖盆中央在高水位期深湖—半深湖相泥岩中发育有低位三角洲砂体 ,其中所含的膏盐岩属于低位期蒸发成因的盐湖沉积。低位三角洲发育在主要物源区的前方 ,处在深湖相泥岩包围之中 ,相标志、相层序、相模式和砂体的展布特征有别于深水重力流沉积 ,是重要的油气储集体。图 4参

On the basis of restudy of the origin of halite in Paleogene of Dongpu depression, it was found that the lake level fluctuate frequently during the sedimentation of 3rd member of Shahejie Formation, and the flunctuation frequency is 1000 times per Ma. This article thinks that sandbodies in shale and oil shale of semi-deep lake-deep lake facies in the basin center of Paleogene in Dongpu depression are lowstand delta sandbodies, and that gypsum and halite (often in the center of the basin) is playa lake sediment in low-stand stage. This article also summarizes facies mark, facies sequence, facies model and sandbody spreading character of lowstand delta.