Abstract: Low-resistivity reservoir of Wutonggou formation of the Upper Permian in Xiquan area in eastern Junggar basin is found rather than other areas with middle-high resistivity beyond Xiquan. The reservoir in Xiquan area is characterized by "three lows", namely, low resistivity, low density and low gamma ray. And the lithology of low-resistivity reservoir is medium-fine lithic greywacke with lots of plastic pelolithic texture and calcareous interbeds, belonging to medium porosity and low permeability reservoir, according to the rock samples analysis. The direct reasons for forming low resistivity are high shale content and high water saturation. Through log interpretation for identification of the lithology of reservoir, integrated with seismic interpretation result, the target reservoir's oil is accumulated in the lithologic trap formed during low and lake transgressive system tracts deposition. The scale and distribution of the lithologic reservoir are controlled by the development of lithologic traps. Meanwhile, the formation of lithologic traps is controlled by the depositional setting. These are essential factors for forming the "three lows" in Xiquan area. Exploration survey shows that similar traps in this area are developed widely, which is favorable for shaping lithologic hydrocarbon reservoirs.

Key words: Junggar basin, Xiquan area, low-resistivity reservoir, plastic mud boulder, system tract, bank bar, distribution rule