EGU2020-12037, updated on 12 Jun 2020
https://doi.org/10.5194/egusphere-egu2020-12037
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Isotopic fingerprinting of fugitive methane and CO2 from the Western Canada Sedimentary Basin (WCSB): Data documentation and impact

Kalis Muehlenbachs1 and Gabriela Gonzalez Arismendi1,2
Kalis Muehlenbachs and Gabriela Gonzalez Arismendi
  • 1University of Alberta, Earth and Atmospheric Sciences, Edmonton, Canada
  • 2University of Calgary, Geoscience, Calgary, Canada

The general public, industry and regulators seek information about both intentional and unintentional greenhouse gas (GHG)  emissions from energy wells. Minimizing these emissions may be one of the easiest steps to reaching reduction targets. ẟ13C is a common tool used to assess sources of atmospheric methane. Here we report and map the isotopic composition of 1280 production gases from energy wells in the Western Canada Sedimentary Basin (WCSB), which mark the ẟ13C of downstream GHG emissions in the production and transmission network. The WCSB is a worldwide recognized hydrocarbon producer, with more than 450,000 energy wells drilled only in Alberta. Produced methane ẟ13C ranges from -70‰ (VPDB – biogenic source) to -23‰ (VPDB – over mature shale) averaging, -47.2‰. Many of the currently producing, shut-in and abandoned wells also emit fugitive gas through surface casings (SCVF) and soil/ground migration (GM).  Their ẟ13C of the fugitive gases usually indicates a shallower source than the production target (average SCVF ẟ13Cmethane= - 55.6 ‰, GM ẟ13Cmethane= - 58.0 ‰, and average SCVF ẟ13CO2= - 55.6 ‰, GM ẟ1313CO2= -15.8 ‰). Mapping (isoscapes) of isotope values from 2800 SCVF, and 1800 GM gases sampled across WCSB, show that geology and topography constrain the source of leaks. The spatial distribution and wide range of ẟ13C of fugitive methane across the WCSB provide insights and data to climate modellers seeking to attribute atmospheric methane sources but is also relevant for mitigation of emissions as well as informing regulators.

How to cite: Muehlenbachs, K. and Gonzalez Arismendi, G.: Isotopic fingerprinting of fugitive methane and CO2 from the Western Canada Sedimentary Basin (WCSB): Data documentation and impact , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12037, https://doi.org/10.5194/egusphere-egu2020-12037, 2020

Comments on the presentation

AC: Author Comment | CC: Community Comment | Report abuse

Presentation version 1 – uploaded on 05 May 2020 , no comments