Fracture characteristics of Carboniferous volcanic reservoirs in Hongche fault belt of Junggar Basin

Based on core observation,well drilling and image logging data,the fracture characteristics of Carboniferous volcanic reservoirs in Hongche fault belt of Junggar Basin are studied.The result shows that fractures in volcanic reservoirs are well developed.They are mainly structural fractures formed in the tectonic movement,and most of them are filled with some kinds of solid minerals,which affects the effectiveness of the fractures to petroleum accumulation and migration.The main fracture directions are NNE and NNW,consistent with outstanding tectonic direction.According to the fracture characteristics and origin,the fractures are divided comprehensively.The relation between fracture and tectonic movement is discussed,and it is recognized that the four stages of fracturing are corresponding with the tectonic movement.Fractures mainly distributed at the depth of 250 meters under the top of Carboniferous in the vertical,and concentrated in Hongche fault belt and around secondary fault in the plane.