SciTech Connect

Title: Water-related Issues Affecting Conventional Oil and Gas Recovery and Potential Oil-Shale Development in the Uinta Basin, Utah

Water-related Issues Affecting Conventional Oil and Gas Recovery and Potential Oil-Shale Development in the Uinta Basin, Utah Saline water disposal is one of the most pressing issues with regard to increasing petroleum and natural gas production in the Uinta Basin of northeastern Utah. Conventional oil fields in the basin provide 69 percent of Utah?s total crude oil production and 71 percent of Utah?s total natural gas, the latter of which has increased 208% in the past 10 years. Along with hydrocarbons, wells in the Uinta Basin produce significant quantities of saline water ? nearly 4 million barrels of saline water per month in Uintah County and nearly 2 million barrels per month in Duchesne County. As hydrocarbon production increases, so does saline water production, creating an increased need for economic and environmentally responsible disposal plans. Current water disposal wells are near capacity, and permitting for new wells is being delayed because of a lack of technical data regarding potential disposal aquifers and questions concerning contamination of freshwater sources. Many companies are reluctantly resorting to evaporation ponds as a short-term solution, but these ponds have limited capacity, are prone to leakage, and pose potential risks to birds and other wildlife. Many Uinta Basin operators claim that oil and natural gas production cannot reach its full potential until a suitable, long-term saline water disposal solution is determined. The enclosed project was divided into more » three parts: 1) re-mapping the base of the moderately saline aquifer in the Uinta Basin, 2) creating a detailed geologic characterization of the Birds Nest aquifer, a potential reservoir for large-scale saline water disposal, and 3) collecting and analyzing water samples from the eastern Uinta Basin to establish baseline water quality. Part 1: Regulators currently stipulate that produced saline water must be disposed of into aquifers that already contain moderately saline water (water that averages at least 10,000 mg/L total dissolved solids). The UGS has re-mapped the moderately saline water boundary in the subsurface of the Uinta Basin using a combination of water chemistry data collected from various sources and by analyzing geophysical well logs. By re-mapping the base of the moderately saline aquifer using more robust data and more sophisticated computer-based mapping techniques, regulators now have the information needed to more expeditiously grant water disposal permits while still protecting freshwater resources. Part 2: Eastern Uinta Basin gas producers have identified the Birds Nest aquifer, located in the Parachute Creek Member of the Green River Formation, as the most promising reservoir suitable for large-volume saline water disposal. This aquifer formed from the dissolution of saline minerals that left behind large open cavities and fractured rock. This new and complete understanding the aquifer?s areal extent, thickness, water chemistry, and relationship to Utah?s vast oil shale resource will help operators and regulators determine safe saline water disposal practices, directly impacting the success of increased hydrocarbon production in the region, while protecting potential future oil shale production. Part 3: In order to establish a baseline of water quality on lands identified by the U.S. Bureau of Land Management as having oil shale development potential in the southeastern Uinta Basin, the UGS collected biannual water samples over a three-year period from near-surface aquifers and surface sites. The near-surface and relatively shallow groundwater quality information will help in the development of environmentally sound water-management solutions for a possible future oil shale and oil sands industry and help assess the sensitivity of the alluvial and near-surface bedrock aquifers. This multifaceted study will provide a better understanding of the aquifers in Utah?s Uinta Basin, giving regulators the tools needed to protect precious freshwater resources while still allowing for increased hydrocarbon production. « less
Authors: ; ; ; ;
Publication Date:
OSTI Identifier:1051514
DOE Contract Number:NT0005671
Resource Type:Technical Report
Data Type:
Research Org:Utah Dept Of Natural Resources
Sponsoring Org:USDOE
Country of Publication:United States
Language:English
Subject: 58 GEOSCIENCES; 02 PETROLEUM; 03 NATURAL GAS; 04 OIL SHALES AND TAR SANDS