沾化凹陷东北部沙四上亚段-沙三段沉积相研究

沾化凹陷是济阳坳陷东北部的一个次级凹陷，沙四晚期－沙三时期发展成为北陡，南缓的箕状断坳盆地，沙四晚期，沾化凹陷东北部为东西两个湖盆；相应地，沙四上亚段主要发育扇三角洲，膏盐湖及湖泊等（亚）相沉积，并基本呈环带状分布，沙三段以半深湖－深湖亚相、扇三角洲相和湖底扇相沉积为主，基本不发育三角洲相；半深湖－深湖亚相分布最广并略偏北，滨浅湖亚相主要见于南部诸凸起北缘，扇三角洲相主要见于凸起边缘；湖底扇相有两种类型，即：普通湖底扇和槽型湖底扇；普通湖底扇见于南部孤岛凸起北缘地区，槽型湖底扇分布于义和桩凸起和程子口凸起等的陡岸坡脚地带，沙三中亚段，湖底扇有较大发展，分别源于埕子凸起与孤岛凸起的两个湖底扇在Y115井一带交汇，并因受孤西断裂带的隔挡而形成向西突出的形态。

Study on Sedimentary Facies of the Upper Sha-4 - Sha-3 Member of Shahejie Formation (Palaeogene) in the Northeastern of Zhanhua Sag

Zhanhua sag is a sub-sag in the northeastern Jiyang depression. During the late Sha-4 (Es4) - Sha-3 (Es3) epoch (the Fourth - Third Member of Shahejie Formation, Palaeogene), Zhanhua sag was developed into a fault-sag basin steep in the north and gentle in the south. During the late Es4 epoch, the northeastern Zhanhua sag was consisted of two sub-sags, one was located in the east and the other in the west. The deposits were mainly fan-delta, gypsum-salt lake and lacustrine facies, which generally distributed in annuluses. In the Es3 epoch, the deposits were mainly semi-deep-deep lake facies, fan-delta and sublacustrine fan facies. The semi-deep-deep lake facies was the most developed deposits and distributed a little more further to the north of the basin. The shore-shallow lake facies were mainly distributed on the north edges of the bulges in the south. The fan-delta facies were mainly distributed on the edges of the bulges. There were two types of sublacustrine fan facies, i.e., normal type and trough type. The normal sublacustrine fan facies were developed on the north edge of Gudao bulge in the south part, and the trough ones were situated on the slope zones on the steep banks of Yihezhuang bulge and Chengzikou bulge. During the middle of Es3 epoch, sublacustrine fan facies was greatly developed, two sublacustrine fans which were developed originally on the edges of Chengzikou bulge and Gudao bulge were intersected at the area around well Y115. The shape of resulting sublacustrine fan was protruded towards the west by the obstruction of Guxi fracture belt.