Co2 Storage in Depleted Coal Reservoirs Using Tank Model

Reservoir and well properties are collected in table 1 . Methane in drainage area of 160 ac is 1,112.537 mmcf, reservoir flow capacity is 1,525 md-ft and CO2 injection rate is 28mmcfd. The injection rate shown in figure 1 , decreases as coal selling because of sorption of CO2. The injection rate falls by one-half of value after three weeks of injection, and after 50 years of injection, the rate is 46 mcfd. Porosity and permeability assumed to be depended on pressure and gas composition according to Shi-Drucan model. Permeability and porosity ratio demonstrated in figure 2 in drop to 0.10% and 10.22% respectively of their initial value after 50 years of injection. Free and sorbed gas mole fraction slowly vary after 10 years of injection and after 50 years they asymptotically approaches with free gas composition of 71% CH4 and 29% CO2 and a sorbed gas composition of 29% CH4 and 86% CO2. The increase in reservoir pressure increases the sorption capacity of coal for CO2. One –half the value of total pressure increment is reached after 1463 days after 3.9 years.