Abstract
A new coal-bed methane production technology has the added attraction of tackling greenhouse gas emissions. Injection of carbon dioxide, an important anthropogenic greenhouse gas, into deep coal seams can enhance methane recovery, while simultaneously locking up the carbon dioxide in the coal measure. Providing the coal is never mined, the carbon dioxide would be sequestered for many years, and thereby help to avoid climate change. Initial results from the world’s first carbon dioxideenhanced coal-bed methane (CO2-ECBM) pilot in the United States have shown this new technology to be technically and economically feasible. Since 1996, over 57 million m3 (2 Bcf) of CO2 has been sequestered in the coal seams. Based on current costs and performance, CO2-ECBM may be profitable in the United States at prevailing well-head natural gas prices of US$0.06 to $0.07/m3 ($1.75 to $2.00/Mcf), representing an estimated 8.5 Gt of CO2 sequestration potential. The technology for implementing and operating CO2-ECBM recovery is based on demonstrated oil field technology, although further refinements are needed. The worldwide CO2-ECBM potential has been estimated at 150 Gt CO2. Analysis of representative CO2-ECBM projects indicates that 5 to 15 Gt of carbon dioxide could conceivably be sequestered at a net profit, while about 60 Gt of sequestration capacity may be available at moderate costs of under $50/t CO2.