Print this pageArchaea Related to Anaerobic Methane-Oxidizers are Resident in a Biodegraded Subsurface Petroleum Reservoir
Arlene K. Rowan1, Carolyn M. Aitken1, D. Martin
Jones1, Haiping Huang2, Martin Fowler3, John
Cody3, Steve R. Larter2, and Ian M. Head1
1 University of Newcastle, Newcastle, United Kingdom
2 University of Calgary, Calgary, AB
3 Geological Survey of Canada, Calgary, AB
Most of the world's petroleum reserves are partially biodegraded. This is of considerable importance as degradation lessens the economic value and leads to problems during petroleum production. However, relatively little is know about the microorganisms involved in subsurface hydrocarbon degradation. Knowledge of the microorganisms resident in biodegraded subsurface petroleum reservoirs, their physiological properties and potential for oil degradation is therefore important for a better understanding of biodegraded petroleum systems.
Current knowledge on microorganisms present in petroleum reservoirs has been obtained primarily from culture-based studies. Nevertheless, cultivation of representative organisms from petroleum reservoirs can be problematic. Cultivation methods are generally selective, in situ conditions are difficult to assess and replicate in the laboratory and growth of non-resident organisms during production may confound interpretation. In this study we applied culture-independent approaches to determine the archaeal communities present in core samples obtained from a biodegraded petroleum reservoir (Athabasca, Canada). Archaeal DNA extracted from the sediment cores were profiled by genetic fingerprinting and detailed genetic information was obtained by sequence analysis. Archaea were only detected in sediment samples obtained from the oil/water transition zone of the petroleum reservoir but were never detected in sediment samples from elsewhere in the core. The oil/water interface may therefore harbour larger microbial populations and should be targeted for the study of hydrocarbon biodegradation in petroleum reservoirs. Genetic analysis of archaeal sequences revealed that the archaeal communities were dominated by organisms related to anaerobic methane oxidisers suggesting active methane cycling within the reservoir.
AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005