| Natural gas has becoming more and more important resource to human’s life and production. Gas overflow from the rock belongs to the H-M coupling problem which is the interaction between flow and solid matrix, and has been the focus study for the researchers by using the deterministic analysis methods, and remarkable achievements are achieved. Studies show that there is great spatial variability for structure and seepage parameter of rock medium, to study the H-M coupling problem with can’t meet the demand of engineering deterministic theory. Using stochastic FEM by substitute stochastic parameters for deterministic parameters can solve this problem to a certain degree. The results reflect the influence of parameter space variability on stress, pore pressure and flow rate of each node of entire coupling field, and can output the stochastic characteristic which deterministic analysis methods cannot provide.Based on the fundamental equation of stress field and seepage field, firstly, we establish the mathematic H-M coupling seepage model, applying the stochastic FEM to H-M coupling problem, we obtain the theoretical foundation for programming and develop a stochastic FEM program which can solve the homeostasis H-M coupling problem on the basis of the prime program. Then the time item is added to the program so that transient problem can be settled. We use the homeostasis program to simulate a calculation example, analyze the distribution of parameters of the coupling field and discuss the transfer characteristic of randomness in coupling field. We use the transient program to simulate one month gas production of coal-bed gas well in Qinnan, and compare it with in situ date. The instance analysis not only proves the reliability of the problem but can also evaluate the safety and economic benefit of engineering project which provides theoretical support for the gas exploiting techniques. This paper includes 42 diagrams,14 tables and 108 references. |
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