Methods are provided to inhibit scale formation in oil or gas production systems. In one embodiment, the scale inhibiting treatment comprises: A) an AAA terpolymer and B) a phosphonate. The treatment can be added to these systems in the well area itself, to the well annulus and its associated tubes, casings, etc., to the oil or gas bearing subterranean formation, to injection conduits for injecting steam or fracking fluid to the subterranean formation, to the produced water or to equipment in fluid flow contact with the produced water.