Characteristics of Slope Breaks and Its Implication on Petroleum Geology in Yanchang Formation Chang 6 (Late-Triassic) of Ordos Basin

Depressed-type slope breaks was developed in the southwest and northeast margin of the Late-Triassic Ordos Basin.In the northeast margin,the slope breaks were characterized by multistage and gentle,with grade of 1-3 and width of 15~25 km;In the southwest margin,the slope breaks were characterized by monolithic and steep,with grade of 3-5 and width of 10~20 km.Variations of slope breaks distribution were partly affected by the shrinkage of lake basin.However,slope controls formation overlapping,lithologic association and distribution of sedimentary system.To build distribution modeling of slope-nonstructural trap based on the research of slope break characteristics plays an important role in exploration activity of the Late-Triassic Ordos Basin.