Managing the Increasing Water Footprint of Hydraulic Fracturing in the Bakken Play, United States.

The water footprint of oil production, including water used for hydraulic fracturing (HF) and flowback-produced (FP) water, is increasingly important in terms of HF water sourcing and FP water management. Here, we evaluate trends in HF water use relative to supplies and FP water relative to disposal using well by well analysis in the Bakken Play. HF water use per well increased by ∼6 times from 2005-2014, totaling 24.5 × 10(9) gal (93 × 10(9) L) for ∼10 140 wells. Water supplies expanded to meet increased demand, including access of up to ∼33 × 10(9) gal/year (125 × 10(9) L/year) from Lake Sakakawea, expanding pipeline infrastructure by hundreds of miles and allowing water transfers from irrigation. The projected inventory of ∼60 000 future wells should require an additional ∼11 times more HF water. Cumulative FP water has been managed by disposal into an increasing number (277 to 479) of salt water disposal wells. FP water is projected to increase by ∼10 times during the play lifetime (∼40 years). Disposal of FP water into deeper geologic units should be considered because of reported overpressuring of parts of the Dakota Group. The long time series shows how policies have increased water supplies for HF and highlights potential issues related to FP water management.