Study on Lithologic Reservoir Forming Conditions of Dongying Formation in Dawangzhuang Area of Raoyang Sag

Dawangzhuang area in Raoyang sag is abundant in oil and gas resources and it has favorable structural setting.Sandbody developed in the meandering river channel of Dongying Formation,and reservoir features in medium porosity and medium permeability.The first member of Dongying Formation is a regional cap rock,fault is a major channel for vertical oil and gas migration,oil and gas is migrated terracedly and in the shape of T or reticulately.The area has favorable conditions for the formation of lower-generating-upper reservoiring type sandstone lithologic reservoir.It has favorable conditions for hydrocarbon preservation,after oil and gas are accumulated at Neogene Minghuazhen period,because structural movement gets weakened and fault is not developed.Two typical reservoir-forming patterns exist in the area:one is the pattern of channel sandstone lithologic and updip pinchout reservoir in the negative area of downthrow block of contemporaneous fault;the other is the channel sandstone lithologic and lateral pinchout reservoir in the flank of Dawangzhuang structure.The formation and distribution of channel sandstone reservoir of Dongying Formation is mainly controlled by oil and gas resources,structures and lithology.Oil reservoir is mainly lithologic and structural-lithologic.