Methods for inhibition of scale in high brine environments

A method for inhibiting oilfield scale formation including calcite in a high brine environment comprising introducing an effective amount of a scale inhibiting composition to a high brine environment susceptible to calcite scale formation, said environment having a total dissolved solids content of at least about 150 g/l, and said scale inhibiting composition comprising an aminomethylene phosphonate of the formula ##STR5## wherein x is 2 or 3, each Z is independently selected from the group consisting of H and CH.sub.3 and R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently selected from the group consisting of hydrogen and --CH.sub.2 PO.sub.3 M.sub.2 wherein the M's are independently selected from the group consisting of hydrogen and cations associated with Lewis bases, such that at least about 80% of the R.sup.1, R.sup.2, R.sup.3 and R.sup.4 in the composition is --CH.sub.2 PO.sub.3 M.sub.2.