| Shale gas reservoir has been developed successfully in the United States,China has begun to explore and develop shale gas reservoir. Shale rock Pore-Permeability characteristic and microscopic gas slippage mechanism is researched by using experimental data and mathematical model method in paper, based on a large number of domestic and foreign literatures and shale rocks observation.(1) Pore and permeability of shale gas reservoir is researched in this artile. According to mercury injection data analysis, pore radius is vwry small.The crest value of pore radius is about nm degree in America. So small pore radius will harm its permeability, so some special experimental methods are been researched.(2) In order to solve the problem of permeability, we used fractal method to research its heterogeneity and permeability, matched curve can be devided into two sections.the break point of matched curve if 80% of pore volume.Fractal dimension and permeability own a mathematic relationship.they have positive realationship and negative realationship.(3) There are three kinds of storage gas, free gas and adsorbed gas in wall and adsorbed gas in kerogen. a capillary tube model is been established to research gas slippage mechanism and dynamic permeability by counting Darcy flow and Knudsen diffusion and gas slip and desorption from pore wall and desorption from kergen and pore deform. Through the model, the permeability add firstly, then drops with pressure when the pore diameter is less than 20 nano-meter.it can be researches by Darcy law when the pore diameter is larger than 20 nano-meter.at beginning.(4) knudsen diffusion and desorption from kergeon has little affection on pressure and accumulate gas production. After some time, every factor has showed its action. Pore radius is far larger than other factors. Gas slip is larger than desorption from wall. The desorption gas from wall is larger than desorption from kergen. The desorption from kergen is larger than knudsen diffusion. |
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