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TitleLate Paleocene-middle Eocene hydrocarbon source rock potential in the Arctic Beaufort-Mackenzie Basin
AuthorNeville, L A; McNeil, D H; Grasby, S E; Ardakani, O H; Sanei, H
SourceMarine and Petroleum Geology vol. 86, 2017 p. 1082-1091, https://doi.org/10.1016/j.marpetgeo.2017.06.042
Year2017
Alt SeriesEarth Sciences Sector, Contribution Series 20160322
PublisherElsevier
Documentserial
Lang.English
Mediapaper; on-line; digital
File formatpdf
ProvinceNorthern offshore region
NTS107F; 107C; 117D; 117E
AreaBeaufort-Mackenzie Basin
Lat/Long WENS-140.0000 -136.0000 70.0000 69.0000
Subjectseconomic geology; fossil fuels; general geology; marine geology; offshore wells; exploration wells; source rocks; organic materials; Natsek E-56; Paleocene/Eocene Thermal Maximum (PETM); Azolla Event; Rock-Eval analysis
Illustrationslocation maps; well logs; seismic relfection profiles; tables; graphs; photomicrographs
ProgramWestern Arctic Sverdrup Basin, GEM2: Geo-mapping for Energy and Minerals
AbstractThe Natsek E-56 oil and gas exploration well from the Arctic Beaufort-Mackenzie Basin (BMB) was selected for a multi-disciplinary study because its strata contains a record of two major Eocene climate events that affected source rock deposition: the Paleocene/Eocene Thermal Maximum (PETM) at ~55.5 Ma and the early mid-Eocene Azolla event at ~49 Ma. Rock-Eval data from Natsek E-56 indicates a previously overlooked economically significant interval that occurs just below PETM strata. The pre-PETM unit is an organic rich (~30% TOC) coaly-shale deposit with good source rock potential and marginal thermal maturity. This carbonaceous deposit is characterized by a relatively elevated hydrogen index (HI~149 mgHC/TOC; S2~38 mgHC/g) which suggests increased input of liptinitic-rich material similar to the sapropelic boghead coal formed in lacustrine environments in the vicinity of the modern Beaufort-Mackenzie delta plain.
In recent years, source rock predictions for the Arctic Eocene were postulated from cores on the Lomonosov Ridge, focusing on organic matter (OM) produced during the Azolla event. Similar OM associated with the Azolla event occurs in the Natsek E-56 where TOC ranges from 1-14% but reworked terrestrial matter is dominant. The pre-PETM organic rich interval of Natsek E-56 was not recorded from the Lomonosov Ridge, while in Natsek E-56 the interval consists of TOC values double that recorded at any point from the Lomonosov Ridge. Additionally in the BMB, a younger (early Eocene), but similar, TOC-rich interval was recorded from the oil-bearing Immiugak A-06 well. The occurrence of multiple potential source rocks from unique depositional environments in the BMB indicates significant oil and gas potential in late Paleocene-middle Eocene strata of the Beaufort-Mackenzie region.
Summary(Plain Language Summary, not published)
The early Eocene Arctic (~50 million years ago) was a special time in earth history when CO2 levels were abnormally high and the arctic climate unusually warm ¿ comparable to today¿s southern USA. The early Eocene rocks of the Arctic are also hydrocarbon rich and are an important future resource for Canada. Our current research is multi-disciplinary, involving analyses of petroleum source rocks. The Natsek E-56 oil and gas exploration well from the Arctic Beaufort-Mackenzie Basin (BMB) was selected for the study because its strata contain a record of the major Eocene climate events that affected source rock deposition. In Natsek E-56 we observed an organic rich layer containing total organic carbon (TOC) values of ~30%, with good source rock potential and marginal thermal maturity. This organic rich interval records more than double the TOC values reported on the Lomonosov Ridge during the same time interval. The Lomonosov Ridge is located on the opposite side of the Arctic Ocean to Natsek E-56 and is the only other locality documenting resource potential during this time interval.
GEOSCAN ID299651