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TitleComparison of microbial gas fields in the Western Canada Sedimentary Basin and Qaidam Basin, implications for essential geological controls on large microbial gas accumulations
AuthorChen, Z; Shuai, Y; Osadetz, K; Hamblin, T; Grasby, S
SourceBiogenic gas fields in Canada and China: characterizations and new insights; by Chen, Z (ed.); Grasby, S (ed.); Bulletin of Canadian Petroleum Geology vol. 63, no. 1, 2015 p. 33-52,
Alt SeriesEarth Sciences Sector, Contribution Series 20140388
PublisherCanadian Society of Petroleum Geology
Mediapaper; on-line; digital
File formatpdf
ProvinceAlberta; Saskatchewan
NTS72; 73; 83
AreaQaidam; Canada; China
Lat/Long WENS-120.0000 -104.0000 56.0000 49.0000
Lat/Long WENS 36.0000 38.0000 96.0000 92.0000
Subjectsfossil fuels; stratigraphy; hydrocarbons; gas; biogenic gas; reservoirs; structural traps; mudstones; source rocks; stratigraphic analyses; Western Canada Sedimentary Basin; Sanhu Depression; Qaidam Basin; Sanhu Sag
ProgramShale-hosted petroleum ressource assesment, Geoscience for New Energy Supply (GNES)
AbstractCompared to conventional thermogenic petroleum, the exploration for large biogenic gas accumulations is more challenging because the gas occurs commonly at shallow depths in a petroleum system with weak top and lateral seals. In addition to fundamental environmental requirements, such as temperature and formation water composition, microbial gas generation and retention require adequate petroleum system elements in order to form economic accumulations. The geological characteristics of Southeast Alberta Gas Field (SAGF), a giant biogenic gas accumulation located in southeastern Alberta and southwestern Saskatchewan within the Western Canada Sedimentary Basin (WCSB), are compared to those of Sanhu Sag, Qaidam Basin in northwestern China, to provide insight into the critical geological controls for economic biogenic gas accumulations. It was found that multilayered reservoirs, consisting of multiple layers of thin porous units and interbedded with source rocks, provide a most efficient storage mechanism. Low relief structural and stratigraphic traps with lateral permeability seals, commonly of stratigraphic or diagenetic origin, are the most effective trapping mechanisms. The recognition of these common constraints provides insight for future exploration of other biogenic gas fields and prospects in the basins studied elsewhere.
Summary(Plain Language Summary, not published)
Microbial gases are widely distributed in shallower portions of many sedimentary basins and represent an important source of energy supply. Studies suggest that with better understanding of the preservation, more economic microbial gas is expected to add to future supply. This article examines the geological characteristics of large microbial gas accumulations in Western Canada Sedimentary Basin and the Qaidam Basin in China to better understand the essential geological controls. Many common features are found in these two basins although geological settings of these two basins differ. This study revealed that a self-sourced and self-contained source-reservoir system provides optimal condition for migration and storage.