Abstract: The Carboniferous Kalashayi Formation in the Tahe oil field shows a good potential for hydrocarbon exploration in clastic rocks. Deep burial depth, small sand body scale and complicated controlling factors for hydrocarbon accumulation have made it necessary for a fine scale assessment of the study area. The controlling factors for hydrocarbon accumulation in the Carboniferous Kalashayi Formation, such as oil and gas distribution, fault systems, sand bodies and underlying strata, were analyzed. The maps of reservoir distribution, oil and gas shows, fault location, sedimentary facies and strata layout were applied to make a comprehensive evaluation of the Kalashayi Formation. The study area was divided into three zones. In the most favorable area, we focus on lithologic traps such as underwater distributary channels, underwater flood fans distributed like flakes, and mouth bars. In the favorable area, we look for banded underwater distributary channels, mouth bars and sheet sandstones which were reformed by tides. In the potential area, we look for sand flats distributed like flakes.