Regions: Inuvialuit Settlement Region
Tags: contaminants, environmental assessment, permafrost, site decommission, ground thaw, wastewater
| Principal Investigator: | Dyke, Larry (10) |
| Licence Number: | 12901 |
| Organization: | Geological Survey of Canada |
| Licensed Year(s): |
1998
1997
|
| Issued: | Mar 20, 1997 |
| Project Team: | Jim Hunter, Marin Douma, Chris Hyde |
Objective(s): Permafrost is often assumed to be impermeable to any waste fluid that is considered harmful, is contained in a facility incorporating permafrost as part of the containment, or escapes from a containment facility located in s permafrost area. However, many conditions exist which may favour the flow of fluids through permafrost. Permafrost may contain no ice in the pores of the soil, it may contain appreciable amounts of unfrozen water, it may contain an ice fabric, which when thawed, greatly increases the permeability, or it may be warmed by climate change. Therefore it is necessary to examine locations where fluids other than pure water have been exposed to permafrost to gain a more accurate understanding of how well permafrost contains these fluids and whether permafrost is a suitable condition for containing waste fluids.
Project Description: This project is intended to determine the amount by which fluids disposed of in abandoned oil well drilling mud disposal pits (sumps) have migrated into surrounding frozen ground. The sumps are not presently considered to pose any kind of environmental hazard but they do offer a unique opportunity to determine the effectiveness of permafrost as a containment for waste fluids. The main activity in the field will be to collect smaples of frozen ground around the perimeter of up to four sumps in the Mackenzie Delta area. The samples will be collected from boreholes drilled to a maximum depth of about 5 m, slightly deeper than the depths of the sumps. The primary substance in drilling fluids used for hydrocarbon exploration in this area is potassium chloride. This is added to lower the freezing point of the drilling fluid. The samples collected will be analyzed for this substance. This will be the primary means by which the effectiveness of containment by permafrost is measured. As the same time, surveys to measure the electrical conductivity of the ground will be carried out. Potassium chloride greatly increases the conductivity of the ground and so this kind of survey will help to identify the extent to which material has migrated from a sump.
