Interface identification of weathering volcanic period and reservoir forming control:a case study in the area of western Junggar

The weathering volcanic sub-interfaces in the area of western Junggar can be divided into two types.Type Ⅰ interface in well logging has the characteristics of high GR, low resistance and low volume density,while type Ⅱ interface has the characteristics of high GR, high resistance and high-volume density. By seismic method, the basic feature of the interface is developed on the boundary line of the volcano mechanism, which has the basic characteristics of overlying and strong reflection. The main reservoir formation of the weathering volcanic interface is the migration channel of oil and gas, and the fluid in the interface has a good transformation effect on the upper and lower volcanic rocks of the interface, which will produce micro-cracks and corrosion holes in the rock internal near the interface. Finally, the sub-interface area of weathering volcanic period becomes the dominant area for hydrocarbon accumulation.