"Extract the crude from the salt water and then return the salt water to it's original spot. I don't see a problem."  

The problem lies in the fact that a lot of the saltwater is not injected back into the producing zone, but rather deeper formations. A recent study advocated just what you are saying.




 


"The research said disposal wells in the deep Arbuckle Formation, long a favored place for disposing produced water from drilling, play a role in the surge of earthquakes in the state. The Arbuckle sits above the crystalline basement, which is already an earthquake-prone layer of rock."

"In Oklahoma, the saltwater that comes up with oil and gas can be ten times the amount of produced hydrocarbons. In some areas, such as the Mississippi Lime formation in north central Oklahoma and southern Kansas, produced water can be up to 20 times the volume of oil and gas."

"The researchers said reducing the volume of injected wastewater into the Arbuckle may reduce the amount of triggered seismicity. But they said what's needed is more data to track the injected wastewater below the surface. Another possibility is injecting wastewater back into the producing formation rather than into the Arbuckle or separate disposal zones."