Based on the analysis of past reservoir classification,according to the actual need of finding oil on sandstone reservoir in synclinal area of depression basin,and in term of the fundamental principle of conventional reservoir generation,this paper has proposed a ternary classification composed by three factors of structure,fault and lithology.

Based on the drilling,logging and geochemical data from 32 wells,the deposit and tectonic evolution feature of the Tangyuan fault depression were studied,and the gas accumulation conditions and gas reservoir types were analyzed.