I wonder if geologists 100 megayears or so downstream will scratch their heads and wonder where the fuck all the saltwater chemistry came from in certain old formations recently exposed by uplift and erosion.
“Produced water,” as it is known in the oil industry, is briny fluid trapped in the rock of oil reservoirs. It is by far the largest toxic byproduct produced by the oil industry, and in addition to salt, it is often loaded with chemicals, residual oil and heavy metals.
As oil fields age, water production increases. By one estimate, the volume of water produced by oil fields worldwide exceeds petroleum by a factor of three. According to Department of Energy figures, at the most “mature” oil fields in the United States, the amount of water extracted may exceed oil by more than 50 times.
Produced water represents one of the largest costs incurred by oil companies, since it typically must be trucked to offsite desalinization and treatment facilities, or pumped into deep underground disposal wells.
Currently, 65 percent of water produced annually at American oil fields is reinjected into disposal wells, according to the Produced Water Society, a group of engineers and scientists based in Houston.
In fields where water is not reinjected, it often lingers at the surface in evaporation ponds, where it can leach into surface water or become a dangerous attractant for migratory birds.
http://greeninc.blogs.nytimes.com/2009/09/04/new-solutions-for-oils-produced-water/