Slope structure feature and category in faulted basin-A case study on Qikou sag Bohai Bay basin

Slope structure,one of the most important tectonic elements in faulted basin,lying between high hydrocarbon source depression.As the main sedimentary zone in around the basin,the slope structure produces and holds most of the large-scale lithologic trap,which is the favorable hydrocarbon accumulated tectonic element and the main target for lithologic reservoir exploration and the practical replacement of composite petroleum accumulation belt.In Paleogene,Qikou sag,a typical Paleogene faulted basin,controlled by the differential settlement in basement and inherited movement of basement faults,developed five slope tectonic elements which belong to four different slope categories.They were step-style faulted slope,step-style flexure slope,normal slope and rotate-tilted slope.Five slope structure regularly located around the center of Qikou sag.