Inhibition of scale formation from oil well brines utilizing a slow

Abstract

A method for the inhibition of scale deposition on the surfaces of a well coproducing oil and scale forming brines comprising injecting into the well reservoir an acidic aqueous solution at a first pH containing dissolved therein a scale inhibitor, multivalent metal ions, and a heat sensitive pH increasing substance which decomposes at elevated temperatures liberating an alkaline compound such that the solution is inherently heated by the higher ambient reservoir temperature to a temperature at which the alkaline compound is liberated from the heat sensitive substance thus raising the pH of the solution to a point at which a sparingly soluble multivalent metal salt of the scale inhibitor is phase separated from the solution on the porous surfaces of the reservoir rock formation, providing for a slow release of inhibitor into the produced brines when the well is in its production phase.