The client contacted Antea Group to support them in responding to a pipeline spill of approximately 20,600 barrels of Bakken crude oil in a wheat field in northwestern ND. Challenges included an aggressive schedule, investigating the extent of the release, identifying and selecting a thermal desorption unit (TDU) contractor, and overseeing the excavation of over 1,000,000 CY of soil. Within the spill work area, an abandoned oil well, owned by others, was discovered and associated impacts from those operations were adjacent to and commingled with the pipeline impacts. The impacted area is approximately 15 acres, while the entire project site is 50 acres.
Antea Group’s role was to investigate the extent of the release and to support the TDU contractor in identifying and managing soil to be treated. Our scope of work included:
• Subsurface investigation using laser induced florescence, Geoprobe and sonic soil boring equipment
• 3D mapping of the spill using ArcGIS
• SPCC plan and compliance
• SWPP plan and compliance
• Compaction testing and compliance
• Monitoring/production well installation oversight
• Stakeholder engagement with property owners and neighbors
• Groundwater assessment of shallow zone and regional aquifers
• High density assessment of heavily impacted areas and 3D visualization and modelling of impacts
• Preparation of bid packages for TDU contractors
• Soil sampling program to support excavation and thermal treatment
• Regulatory engagement and advocacy
• Safety support
• Field oversight
• Air monitoring
• Quantity tracking
In addition, Antea Group worked with and supported a University driven agricultural project. The University created 60 crop plots using various types of soil from heavily impacted, to treated, to virgin top soil. Test plots were closely monitored and harvested to determine effects of the release. The plots will be monitored for 4 growing seasons.
The excavation and thermal treatment began in June 2014 and is expected to be completed by July 2017. Quantities of crude oil impacted soil to be removed are estimated at 750,000 tons. After the treated soil is returned to the excavation, clean topsoil will be placed over it and the site restored to agricultural use. Crops will be monitored by the agricultural team managing the test plots.
For more information, see the Oil & Gas Segment.