A comprehensive reservoir study method is employed in the analysis of the Carboniferous volcanic reservoirs in Che-91 wellblock.The result indicates that the reservoirs here consist mainly of explosion-breccia and belong to pore-fracture dual porosity reservoirs.There are always fractures developed in formations overlying the reservoirs

showing clear features of excellent assemblage of upper fractured interval and lower reservoir.The reservoirs are irre-gular massive reservoirs controlled by both edge water and bottom water.The preserving conditions for hydrocarbons are favorable but get much poorer when near the major faults

resulting in heavier oil and oxidative environment.Identifying the area with well-developed fractures can guide the hydrocarbon exploration in the Carboniferous of the region.