Preferably salt water, even.
When I lived there in the sixties, I was surprised to discover that all the "oil derricks" were, in fact, brine wells.
Dow Chemical needed brine for its electrolysis plant that produced chlorine and caustic soda -- the building blocks of most inorganic chemicals.
Their other major plant at the time was in Freeport, TX. It used seawater as a raw material.
The waterkeepers are active here lately squealing about the injection wells and scaring people with claims about chemicals and even radioactive substances being pumped into the ground. Pure idiocy relying on idiocy. The brine comes out of the ground in one place and is pumped back into the ground a few miles away to push the oil toward the well.
Robert Kennedy Jr Backed marxists
I grew up in injection well territory in southwestern Jackson county. Now I live on the other side of the county and they’re doing it here. Most people don’t even notice it without eccoweenies telling them.