... water from onshore fields is reinjected into producing zones for pressure maintenance and enhanced oil recovery (2). Deep well injection into formations with water salinities greater than 10,000 ... with exemption from regulations) accounts for about 30% of total produced water. The remaining water is discharged into surface waters, including coastal waterways, bayous, estuaries, streams, ... Eventually, the bulk of inorganic salts and some dissolved organic species in the released brine reach the adjacent Skiatook Lake, a 4,250-hectare reservoir that provides drinking water to the local...