Assessment of seismic shothole-associated gas seeps, Mackenzie Delta, NWT

Regions: Inuvialuit Settlement Region

Tags: physical sciences, gas seep, natural gas development, seismic activities

Principal Investigator: Smith, Rod (10)
Licence Number: 14561
Organization: Geological Survey of Canada
Licensed Year(s): 2009
Issued: Jul 11, 2009
Project Team: Lesk-Winfield, Kevin (GIS Technician, NRCan)

Objective(s): From an ongoing compilation of approximately 214 sites with gas seeps, this study proposes to revisit as many sites as possible that are land-based, or in near shore lake/pond environments, in order to determine which, if any, are still seeping gas.

Project Description: Dr. Rod Smith’s ongoing compilation of drillers’ log records from geophysical seismic exploration activities in the Mackenzie Delta and vicinity has identified approximately 214 sites where “gas” was reportedly encountered. This study proposes to revisit as many as possible of these sites that are land-based, or in near shore lake/pond environments, in order to determine which, if any, are still seeping gas.

This study proposes to visit each of the seismic shothole-related fugitive gas seep sites in the Mackenzie Delta area, using a helicopter, based out of Inuvik. Coordinates for the gas seep sites exist within the published databases, and were derived from Industry seismic survey files. Over the course of 5 days, the researcher proposes to visit as many seep locations as possible; landing 50 m or more away from each locale, and then approaching the site on foot. Industry-standard hand-held gas detection equipment would be used to determine if gas were seeping from land-based sites. If so, gas samples will be collected using a simple funnel and gas-trap bottle assembly. Seep locations within water bodies will be inspected for the presence of tell-tale bubble plumes. An inflatable boat will be used to reach such sites; sampling will be done by holding a water-filled bottle over the gas plume and allowing the gas to displace the water from the bottle. These small (1 litre) samples of the gas will be collected for analysis in order to assess potential source(s) of the gas and mechanisms for its release (e.g., leakage from geological reservoirs through faults and/or thinning permafrost). Sites in the shallow marine environment will be visually inspected by helicopter, but are unlikely to be sampled. If offshore seeps are identified, then a follow-up sampling program may be undertaken in a subsequent field season. It may also be possible to get colleagues working on other research projects in the near-shore marine environment to undertake sampling of seeps on the researcher’s behalf.

Recovered gas samples will be analysed at the Geological Survey of Canada, Calgary office in order to determine their composition. Isotopic analyses of the gas samples will be analysed at the University of Calgary Isotope Science Laboratory. Analytical results will be used to identify the potential origins of the gas, and relate them to known gas characteristics from existing reservoirs in the Mackenzie Delta region.

Understanding the aerial extent and possible geological association(s) of fugitive gas seeps will involve modeling of permafrost and talik formation, and assessment of regional fault systems through existing datasets and collaboration with Industry partners.

This project could hire an aboriginal field assistant to accompany researchers on daily helicopter transects, and field sampling activities.

Within one month of the field work being completed, a preliminary report outlining what work was undertaken, and what samples were collected will be sent to the communities of Tuktoyaktuk and Inuvik. Subsequent progress reports will be provided to the communities as analytical data are recovered. They will also be provided with copies of all conference poster presentations and abstracts throughout the life of this project. Results of this study will be published in freely-downloadable GSC publications, and as a peer-reviewed scientific paper(s); print and digital copies of these will be provided to the communities.

The fieldwork for this study will be conducted from July 10 to July 31, 2009. All of the identified gas seep sites that will be visited as part of this research are situated in the Mackenzie Delta between 68.9-69.8°N and 131.5-136.5°W; all within the NWT, and all within the Inuvialuit Settlement Area. Most sites are situated on Richards Island, but the study area extends west to the Olivier Islands on Shallow Bay, and includes sites 20-60 km southwest of Tuktoyaktuk, as well as one site south of the eastern end of Eskimo Lakes.
Base camp location will be dictated by the helicopter provider, and will either be located in Tuktoyaktuk, or Inuvik. No remote field camps are planned as part of this research.