Oil and Gas in the Uinta Basin, Utah, USA — What to Do With the Produced Water?

Abstract

Oil and gas fields in the Uinta Basin of eastern Utah produced 27 million BO and 446 BCFG in 2013 from the Tertiary Wasatch and Green River Formations and several formations in the Upper Cretaceous Mesaverde Group. Over 105 million bbls of water was also produced with these hydrocarbons. Extensive drilling for lenticular, tight gas sands in the Wasatch and Mesaverde occurred in the eastern part of the basin, whereas large drilling programs as part of expanding waterflood projects for oil in the Green River continued in the south-central basin; 1550 wells were permitted in 2013. The environmentally sound disposal of produced water affects the economics of the hydrocarbon resource development in the basin. Specific Uinta Basin water issues include: water use/reuse for well drilling and completion (fracking), appropriate sites for disposal/reuse of water, development of systems to manage the produced water streams, and differing challenges for gas versus oil producers. Current produced water disposal practices in the Uinta Basin consist of (1) injection in deep wells below the base of a moderately saline aquifer in the Green River Formation, (2) storage and evaporation in lined disposal ponds, and (3) supplying water for flooding in enhanced-oil recovery (EOR) programs. Our study evaluated the thickness, structure, porosity, permeability, water quality, and temperature of all aquifer/reservoir units in the basin from the surface (alluvium) through the Jurassic Glen Canyon Group. From this evaluation, the Birds Nest Aquifer in the upper Green River is the most widespread and economically viable disposal unit in terms of depth, proximity to producing wells, and water quality. Statistical analysis of water production quantity and quality identified and forecasted volume trends. For example, the greatest need for water disposal results from drilling gas wells in the eastern part of the basin whereas water is needed for EOR projects in the south-central basin. These needs will continue, based on predicted drilling trends, and thus we suggest that excess compatible produced water from gas wells be transported to oil fields undergoing EOR. Produced water could also be used for fracking water as fracking is required for tight-gas sand and potential shale-gas reservoirs in the basin. Finally, the heat content of produced waters, although generally too low for power generation, could be used locally for space heating and engineering purposes.

AAPG Datapages/Search and Discovery Article #90216 ©2015 AAPG Annual Convention and Exhibition, Denver, CO., May 31 - June 3, 2015