Lithology,Porosity Characteristics and Evolution Model of Volcanic Rocks in Northwest Junggar Basin
This paper studied the lithologic characteristics,porosity and its evaluation,forming mechanisms of six kinds of volcanic rocks,and analyzed the evaluation history and the key factors about the main volcanic reservoirs,including andesite,basalt and tuff,etc.It is concluded that the volcanic rocks itself could not become reservoirs unless being reformed by erosion and tectonic movement.The evolution history of the volcanic rocks goes through five stages,the forming stage,the weathering and leaching stage,the burial and tectonic-reforming stage,the erosion stage and the oil and gas accumulation stage.Finally,the model of porosity evolution was set up with andesite and basalt as examples.