Abstract:

Taking the He 8 tight sandstone gas reservoir in the east of Sulige gas field as an example, the authors conducted a series of experiments including nuclear magnetic resonance, constant-speed mercury injection, casting thin slice, reservoir property, X-ray and so on. With all these techniques,we discussed the microscopic geological factors which affect the distribution of movable fluid. The researches show that: the saturation of movable fluid in He 8 reservoir was low while the distribution of T₂ spectrum was bimodal pattern with high left side and low right side. The filling of clay mineral and pore types were the key factors that resulted in complicated pore structures. Pore structure had great impact on the saturation of movable fluid. Facial porosity, throat radius, the rate of pore radius and throat radius were the key factors which affected the saturation of movable fluid. The effective pore volume and sorting coefficients affected the saturation of movable fluid obviously, while the physical properties of reservoir, clay mineral, effective throat volume and pore radius had moderate effect on the saturation of movable fluid.

Key words: Sulige gas field, tight sandstone gas reservoir, microscopic geological factor, movable fluid, pore structure, physical property, clay mineral