The objective of this paper is to present a new dynamic permeability model to improve modeling of production from coalbed reservoir. Currently, most modeling approaches for coalbed reservoir permeability only consider one single factor. Little research have been done on parameter sensitivity analysis. We improved the description of coalbed reservoir permeability model by considering effective stress, matrix shrinkage and Klinkenberg effect. To amend the P&M model, the dynamic permeability model is given in the form of piecewise function. Next, parameter sensitivity analysis was taken based on this new model, and the following conclusions were drawn: 1) Large Young's modulus, Poisson's ratio, critical desorption pressure and Langmuir volume strain value have greater improvement effect on permeability; 2) The greater the initial porosity, the smaller the times permeability increase; 3) Klinkenberg effect has more obvious influence on permeability under the condition of lower pressure. This gives us a message: In the whole development process, we should use the dynamic permeability index to adjust and optimize the production system continuously.

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