Hydrocarbon accumulation in Silurian updip pinch out traps, Tahe region, Tarim Basin

High-yielding oil flow was found in Paleozoic clastic rocks in Well S112-2 of Tahe region in 2005.The oil flow is on the unconformity interface between Carboniferous and Silurian;hence the origin still remains discussion.Based on core,logging and seismic data,the date,tectonic and trap features of the Well S112-2 reservoir were concluded.2 types of sandstone updip pinch out trap exist in Silurian in the region: a) tongue-shape ones,with monocline at the top of sandbody and pinchout line leading to the north;b) nose-shape ones,with nose-shape structure at the top of sandbody and straight pinchout line.The nose-shape ones are new trap types which may have similar oil-bearing features in the region.