Abstract: Reserves estimation and classification in reservoir are important step in the CBM field development. Estimation both parameters are depend on radius of investigation and radius of desorption. This study propose semi analytical method for estimation of radius of investigation combining with radius of desorption. Desorption radius was estimated using cumulative gas production data. Cumulative water production data, fractional flow curve and sigmoid function are used to estimate water saturation distribution as a function of time and radius, this concept was used to estimate radius of investigation. Numerical model was developed to verify proposed radius of desorption and radius of investigation calculation results. Evaluation using San Juan Basin coal reservoir properties was conduct to understand and check applicability of proposed method. This proposed method can estimate radius of desorption and radius of investigation simultaneously using gas and water production rate and cumulative data. Comparison proposed method with reservoir simulation results are in very good agreement. Since, time parameter is not used in the calculation, this method is very simple in practical manner.
Dedy Irawan, Doddy Abdassah, Zuher Syihab and Ratnayu Sitaresmi, 2017. Radius of Investigation and Radius of Desorption in CBM Reservoir. Journal of Engineering and Applied Sciences, 12: 6045-6051.