In the simplest of terms, Brine is salt water.  The Brine water extracted in oil production also contains various minerals and additives that make it potentially dangerous to ground water sources If the U.S. produces 9 million barrels (2009 figures) of oil per day then this results in the needed disposal or distillation of 36 million barrels of brine water, PER DAY, just to support U.S. production