济阳坳陷车15井区沙三下浊积扇沉积特征及分布格局

根据岩心、地震、测/录井资料,在济阳坳陷车镇凹陷车15井区的沙三下砂砾体中识别出滑塌浊积扇和深水浊积扇.其中,车57井以粒度偏细且有根的深水浊积扇与深湖相互层为特色,车古25井以具水道补给的(有根的)滑塌浊积扇为特色.平面上,自北而南顺水道方向由陆向湖盆中心,依次分布着近岸水下扇、深水浊积扇或滑塌浊积扇、深湖亚相,两类扇体沿主构造线串珠状排列,包裹于大片的深湖相中,呈现"深湖包扇"的沉积格局.不同时期两类扇的演化不同:无根的滑塌浊积扇在第1期最为发育;第5期发生了湖平面上升,扇体范围明显缩小;第7期仅见有根的深水浊积扇与滑塌浊积扇,分布面积不大,但无根的滑塌浊积扇消失.

Sedimentary characteristics and distribution of turbidity fans of the lower third Member of Shahejie Formation in Che-15 wellblock,Jiyang Depression

Based on core,seismic and well-logging data,the slide turbidity fan and deep-water turbidity fan are recognized from gravel sandstones in the lower third Member of Shahejie Formation in Che-15 wellblock.The interbeds of fine grain rooted deep-water turbidity fan with deep lacustrine facies are found from Che-57 well,and the rooted slide turbidity fan with water channel supplying is found from Chegu-25 well.The nearshore subaqueous fan,deep-water turbidity fan or slide turbidity fan,deep lacustrine subfacies distribute in turn along water channel from north to south.The two kinds of turbidity fans distribute along main tectonic orientation in the form of a string of beads,and they are encapsulated in deep lacustrine facies.The two kinds of turbidity fans have different evolution processes in different stages.No-root slide turbidity fan was the most developed in the first stage.The development range of turbidity fan reduced in the fifth stage.There developed rooted slide turbidity fan and rooted deep-water turbidity fan in the 7th stage,whose distribution area is not large,but the rootless slide turbidity fan disappeared.