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Fracturing Water Quality Western North Dakota Water Resources Opportunities 10 Dec 2009 Mike Eberhard P.E. Technical Manager Denver, CO Water Considerations Water sources • Well, municipal, river, reused, etc. Environmental Impact Costs to acquire and dispose • All inclusive Storage and handling • Pits or tanks • Trucking or pipeline Regulatory requirements • Federal, State, BLM, etc. © 2009 Halliburton. All Rights Reserved. 2 Water Quality Concerns Treatment Type • Gelled fluid or water frac Bacteria, scaling, residual chemicals Water analysis • TDS, hardness, cations, anions • Scaling tendencies Consistency is imperative © 2009 Halliburton. All Rights Reserved. 3 Water Quality Guidelines Water Quality Targets Limit* 6 – 8.5 pH < 2,000 ppm Ca & Mg Comments Interferes w/ hydration of polymer, scale Scales, interferes w/ breakers Fe < 10 ppm Catalyst for polymer oxidation, scale Ba & Sr < 5 ppm Reducing agents, interferes w/ breakers Chlorides Bicarbonates Phosphates < 300 ppm < 5 ppm < 500 ppm Sulfates * Limits <40,000 ppm Interferes w/ hydration of polymer and breakers In the presence of Ca and Mg will scale when heated, delay crosslink Interferes w/ metal crosslinker Scales, crosslinker precipitation are interdependent © 2009 Halliburton. All Rights Reserved. 4 Bacteria Can double in population every 20 min Can cause formation damage and H2S Significant problem in reused fluids © 2009 Halliburton. All Rights Reserved. Bacterial Level (count/mL) Days to Gel Degradation < 104 3 105 2 >106 <1 5 Typical Gelled Frac Fluid Chemistry Base water Temporary clay control Biocide Scale inhibitor Gelling agent pH buffer Crosslinker Surfactant Breaker © 2009 Halliburton. All Rights Reserved. 6 Flowback Water/Produced Brines Mixing different waters may exaggerate scaling problems Storage and handling Water treatment • Filter as required • Bacteria shock then store Retreat for bacteria on fly • Remove bad actors (Ca, Mg, Ba, Sr, Fe) • Add scale inhibitors as needed, based on source water Lab testing • Cores for formation damage • Chemical compatibility Dilute w/ fresh water to get below limits © 2009 Halliburton. All Rights Reserved. 7 Bakken Water Analysis BPW RMW Na+ 54,690 40 (mg/l) K+ 2,232 7 (mg/l) Mg2+ 544 25 (mg/l) < 2,000 Ca2+ 4,131 37 (mg/l) < 2,000 Sr2+ 178 1 (mg/l) <5 Ba2+ 1 0 (mg/l) <5 Fe2+ 26 0 (mg/l) < 10 Cl- 96,400 47 (mg/l) < 40,000 SO42- 670 118 (mg/l) < 500 Alkalinity 366 162 (mg/l) < 300 160,000 440 (mg/l) Calc. Density (STP) 1.100 0.997 (g/ml) < 1.038 pH, measured (STP) 7.11 7.41 pH 6 - 8.5 TDS (Measured) Bakken Produced Water – BPW, Referenced Municipal Water - RMW © 2009 Halliburton. All Rights Reserved. 8 Limits Formation Water Scaling Tendencies © 2009 Halliburton. All Rights Reserved. 9