DefinePK

Abstract

The study of Enhanced Coalbed Methane Recovery (ECBM) has become the interest of many researchers in many tertiary research institute. Various recovery techniques have been identified and implemented to increase the production of methane from coal bed reservoirs. One of the method is CO2 injection into coal seams where it helps to maximize the displacement of the adsorbed methane from the surface of coal matrix and enhance the methane recovery. A numerical model from Turkish Coal Seam Bed from Amasra Coal Field, Turkey was developed using CMG-GEM software by Computer Modelling Group to simulate the primary methane production and enhance recovery using CO2 injection. The key petrophysical reservoir parameters to drive the CO2 injection in coal bed methane reservoir are cleat permeability, cleat porosity, methane adsorption time, methane Langmuir isotherm and CO2 Langmuir isotherm. Palmer and Mansoori parameters (porosity, compressibility and coal seam pressure) were also applied to model the compaction and dilation process as well. 3 cases were constructed to evaluate the impact of CO2 injection on methane recovery. Case 1 act as the base case where there is no CO2 injection and is used in the first model while Case 2 includes the CO2 injection in the coal beds. On the other hand, Case 3 was constructed to analyse the impact of different injection timing to investigate the final methane recovery. Other than that, the effect of varying parameters such as cleat porosity, cleat permeability and coal density were also assessed. The results show that the amount of methane recovered in the primary production is 28.2 Bscf while 45.4 Bscf of methane gas was recovered by CO2 injection in Case 2. Therefore, it is found that the total recovery of methane from coal seams during enhanced production is more than that of primary recovery during the preliminary simulation model.