Carbon dioxide sequestration is a promising technology for reducinganthropogenic greenhouse gas emissions while fossil fuels are still being used.The costs associated with CO2 sequestration are often high; however, in certain circumstances (e.g., enhanced oil recovery) these costs can be morethan offset by the benefits of additional incremental hydrocarbon production.Primary production of coalbed methane is a well-developed technology, butsecondary production, through the injection of CO2 or N2has undergone relatively little study. Recent research suggests that carbondioxide preferentially sorbs to coal, displacing methane, makingCO2-enhanced coalbed methane production an ideal candidate forCO2 sequestration. We use PSU-COALCOMP, a dual-porosity coalbed methane simulator, to modelprimary and secondary production of methane from coal, for a variety of coalproperties and operational parameters. Our base well pattern consists of fourhorizontal production wells that form a square, with four smaller horizontalproducers/injectors at the square's center. Primary production of methane andwater is simulated until a specified reservoir pressure is reached, after whichCO2 is injected in the center wells to displace methane, extendingthe reservoir's production of methane. Production continues until theCO2 concentration in the produced gas is too high. By modifying coalproperties, such as permeability, porosity, degree of anisotropy, and sorptionrates, we have approximated different types of coals. By varying operationalparameters, such as injector length, injection well pressure, time toinjection, and production well pressure, we can evaluate different productionschemes to determine an optimum for each coal type. Any optimization requires considering a tradeoff between total methaneproduced (or CO2 sequestered) and the rate of methane production.Values of aggregate methane production and methane production rate arepresented for multiple coal types and different operational designs. Introduction Concern about the quantity of anthropogenic greenhouse gas emissions hasgrown steadily over the past few decades because of their potential forcontributing to global warming. One of the most promising new technologies forreducing carbon dioxide emissions while allowing for continued fossil fuel useis carbon sequestration. Coal seam sequestration is an option with greatpotential because CO2 becomes chemically bound or sorbed to the coalsurface, reducing its mobility and decreasing the chances that it will escapeinto the atmosphere, and because CO2 displaces methane in the coalseam, making the sequestration more economically viable.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractFossil fuels are a major source of the world's energy production and this is expected to be the case well into the 21 st century. Consequently, the extensive utilization of fossil fuels has measurably increased the total load of one of its byproducts, carbon dioxide (CO 2 ), in the atmosphere and concern about the effects on global warming has prompted the inception of various methods and policies geared at reducing the concentration of this green-house gas in the atmosphere. One of the more promising technologies is CO 2 sequestration which involves the capture, separation and storage of CO 2 .Production of coalbed methane is a well-developed technology, but enhanced recovery by CO 2 injection has undergone relatively limited research. Recent research suggests that CO 2 preferentially sorbs to coal, replacing the coalbed methane which can be produced and sold to offset the costs of sequestering CO 2 thereby providing a dual role for unmineable coal seams; a source of coalbed methane and a repository for the sequestration of CO 2 . Production operations from a carbon dioxide-enhanced coalbed methane recovery pilot project, in the San Juan Basin, indicate that the process is technically and economically feasible.Based on the data, results and analyses obtained from the simulations performed during the parametric study, a CO 2 performance predictor tool is developed by employing neurosimulation methods. This tool is able to predict the values of the performance indicators of the CO 2 sequestration process for a wide range of coal-seams and various production schemes within an acceptable margin of error and in a timely and efficient manner. The predictive capabilities of this tool also enables it to be used as a screening tool that has the ability to ascertain the viability of various coalbed reservoirs for the sequestration of CO 2 , as well as the optimum production scheme to be used in any given project.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractFossil fuels are a major source of the world's energy production and this is expected to be the case well into the 21 st century. Consequently, the extensive utilization of fossil fuels has measurably increased the total load of one of its byproducts, carbon dioxide (CO 2 ), in the atmosphere and concern about the effects on global warming has prompted the inception of various methods and policies geared at reducing the concentration of this green-house gas in the atmosphere. One of the more promising technologies is CO 2 sequestration which involves the capture, separation and storage of CO 2 .Production of coalbed methane is a well-developed technology, but enhanced recovery by CO 2 injection has undergone relatively limited research. Recent research suggests that CO 2 preferentially sorbs to coal, replacing the coalbed methane which can be produced and sold to offset the costs of sequestering CO 2 thereby providing a dual role for unmineable coal seams; a source of coalbed methane and a repository for the sequestration of CO 2 . Production operations from a carbon dioxide-enhanced coalbed methane recovery pilot project, in the San Juan Basin, indicate that the process is technically and economically feasible.Based on the data, results and analyses obtained from the simulations performed during the parametric study, a CO 2 performance predictor tool is developed by employing neurosimulation methods. This tool is able to predict the values of the performance indicators of the CO 2 sequestration process for a wide range of coal-seams and various production schemes within an acceptable margin of error and in a timely and efficient manner. The predictive capabilities of this tool also enables it to be used as a screening tool that has the ability to ascertain the viability of various coalbed reservoirs for the sequestration of CO 2 , as well as the optimum production scheme to be used in any given project.