Abstract
The Williston Basin, which includes parts of Montana,
North Dakota, and South Dakota in the United States and the
provinces of Manitoba and Saskatchewan in Canada, has been
a leading domestic oil and gas producing region for more than
one-half a century. Currently, there are renewed efforts to
develop oil and gas resources from deep geologic formations,
spurred by advances in recovery technologies and economic
incentives associated with the price of oil. Domestic oil and
gas production has many economic benefits and provides a
means for the United States to fulfill a part of domestic energy
demands; however, environmental hazards can be associated
with this type of energy production in the Williston Basin,
particularly to aquatic resources (surface water and shallow
groundwater) by extremely saline water, or brine, which is
produced with oil and gas. The primary source of concern is
the migration of brine from buried reserve pits that were used
to store produced water during recovery operations; however,
there also are considerable risks of brine release from pipeline
failures, poor infrastructure construction, and flow-back water
from hydraulic fracturing associated with modern oilfield
operations.
During 2008, a multidisciplinary (biology, geology,
water) team of U.S. Geological Survey researchers was
assembled to investigate potential energy production effects
in the Williston Basin. Researchers from the U.S. Geological
Survey participated in field tours and met with representatives
from county, State, tribal, and Federal agencies to identify
information needs and focus research objectives. Common
questions from agency personnel, especially those from the
U.S. Fish and Wildlife Service, were “are the brine plumes
(plumes of brine-contaminated groundwater) from abandoned
oil wells affecting wetlands on Waterfowl Production Areas
and National Wildlife Refuges?” and “are newer wells related
to Bakken and Three Forks development different than the
older, abandoned wells (in terms of potential for affecting
aquatic resources)?” Of special concern were the wetland
habitats of the ecologically important Prairie Pothole Region,
which overlays a part of the Williston Basin and is recognized
for the production of a majority of North America’s migratory
waterfowl.
On the basis of the concerns raised by on-the-ground
land managers, as well as findings from previous research,
a comprehensive study was developed with the following
goals: summarize existing information pertaining to oil and
gas production and aquatic resources in the Williston Basin;
assess brine plume migration from new and previously studied
sites in the Prairie Pothole Region; perform a regional, spatial
evaluation of oil and gas production activities and aquatic
resources; assess the potential for brine contamination to wetlands
and streams; and hold a decision analysis workshop with
key stakeholders to discuss issues pertaining to oil and gas
production and environmental effects and to identify information
gaps and research needs.
This report represents an initial, multidisciplinary
evaluation of measured and potential environmental effects
associated with oil and gas production in the Williston Basin
and Prairie Pothole Region. Throughout this report there are
reviews of current knowledge, and discussions relating to
data gaps and research needs. On the basis of the information
presented, future research needs include: regional geophysical
and water-quality assessments to establish baselines for
current conditions and estimate the extent of previous brine
contamination, investigations into the direct effects of brine to
biotic communities, and evaluations to identify the most effective
techniques to mitigate brine contamination.
U.S. Department of the Interior |
U.S. Geological Survey