The review on the predictive methodology of coalbed methane recovery efficiency

The predictive methodology of CBM recovery efficiency involving the geology analogy,desorption,reduced-gas content estimation,adsorption isotherm and CBM reservoir numerical simulation is reviewed in the paper.The principle,applicable condition and existent problem of each method are discussed separately, and the determination method of key parameters is introduced in detail.Though simple the computation process of desorption,reduced-gas content estimation and adsorption isotherm is,the reliability of recovery efficiency according to that is dissatisfactory because of its fewer considerable factors.The geology analogy lies on the investigative degree of researchers for studied block and analogy block and their own technique level and experiments.The CBM recovery efficiency from reservoir numerical simulation is more exact,regardless of its more narrow applicable range,its more necessary data and its more complex computation.