Abstract: The in-depth analysis of W eimark-2 gas-bearing structure shows that the main targets for exploration should be the reservoir with low porosity-low permeability and extremely low porosity-extremely low permeability, and gas enriches in lower sand section of Silurian, dominated by wet gas. The gas supply is both from late kerogen pyrolysis gas and crude cracked gas, with mixture feature of the same source and different stages. There exist two stages of petroleum accumulation principally formed in period of Himalayan movement. The efctive reservoir- cap assemblage, relatively homogeneous reservoir rocks, developed fractures and locations as well as faults in two sides of the anticline are the main controlling factors for forming reservoirs.

Key words: Tarim basin, structure, gas reserycir, reservr-forming condiltion, contro