A Multi-Disciplinary Approach to Site Characterization and Remediation of Contamination from Oilfield Produced Waters, East Poplar Oil Field, Fort Peck Indian Reservation, Roosevelt County, Montana
Previous studies conducted by the United States Geological Survey (USGS) and the Fort Peck Indian Tribes, Office of Environmental Protection indicated that the shallow Quaternary aquifer in this region has been heavily impacted by historical oil and gas operations.
An investigation conducted by Pioneer in late 1999 and early 2000, revealed that a previously plugged and abandoned well, the Mesa Biere #1-22 acquired through acquisition, was leaking outside of the casing at approximately 1,000 feet below ground and that brine was channeling upwards into the shallow aquifer approximately 40 feet below the ground surface. The well was plugged in 2000. From 2001-2005 Pioneer conducted further delineation drilling and aqueous geochemical analyses of the area around the Mesa Biere #1-22 well.
Beginning in mid-2006, Pioneer initiated an integrated approach to characterize both the regional setting of the oilfield contamination including a detailed study of the geological, hydrological, aqueous-geochemical and geophysical setting the Biere #1-22 contaminant plume area. The results of the detailed study of the Biere #1-22 plume area revealed that the contaminant plume was located within an isolated, well-defined channel of fine to coarse-grained gravels of glacio-fluvial origin. Site and aquifer characterization studies were conducted with numerous pump and slug tests. The data was input into a 3-D groundwater model and plume capture scenarios utilizing different recovery well placements and pumping rates were run to evaluate the feasibility of undertaking remedial actions of the Biere #1-22 plume.
Pioneer proactively and voluntarily committed more than $6 million to design and build a plume capture and remediation system. The system consists ten “brine”, groundwater removal wells, five crude oil recovery wells and Pioneer drilled a deep 7,800 foot, USEPA Class V, injection well into the Mississippian, Mission Canyon and Devonian, Nisku Formations. The brine remediation system became operational in August 2008. The designed system will remove the most contaminated portion of the plume at a rate of approximately 250,000 gallons per day and will significantly reduce any potential threat to the City of Poplar.
The project was the recipient of the United States Department of Interior "Environmental Achievement" award for 2008
AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009