Special Report 081

Special Report 081

SPE 081

Water Chemistry of Coalbed Methane Reservoirs; Central Alberta, 2005

Author(s) Lemay, T.G. Konhauser, K. Date 2006-09-01

Unconventional natural gas resources such as coalbed methane are likely to become more important as conventional natural gas supplies in the Western Canada Sedimentary Basin continue to decline. Keys to discovering and developing these unconventional resources include a fuller understanding of the processes leading to the generation of gas in these reservoirs, and a sound strategy for handling produced water associated with gas production. Groundwater sampling, including innovative techniques such as groundwater age-dating and geomicrobial identification in groundwater, along with more standard chemical analysis of water samples will lead to breakthroughs in our understanding of unconventional gas production in Alberta's unconventional gas reservoirs, as well as provide information vital to the responsible and safe handling of produced water. Information on groundwater microbiology, age and standard chemistry is highly beneficial to CBM development companies allowing them to conduct more efficient exploration programs and implement more economical water handling practices.

With this in mind, the AGS initiated a sampling program to collect water samples from gas producing wells and adjacent wells used for domestic or agricultural purposes. The interpretation of the results will help enable: 1) the development of a better understanding of coalbed methane generation and its resource potential in Alberta; 2) the development of potentially new exploration strategies based on water chemistry and geomicrobiology; 3) the assessment of the connection between gas-producing and domestic or agricultural water use zones of coalbeds; 4) the development of water handling and disposal strategies consistent with the goals of regulators, stakeholders and developers; and 5) the compilation of baseline datasets for future reference.

Lemay, T.G. and Konhauser, K. (2006): Water chemistry of coalbed methane reservoirs; Alberta; Alberta Energy and Utilities Board, EUB/AGS Special Report 81, 372 p.