CHARLES GAY, MD
Marriage and Family Therapists at Palm, Bellvue, TX

5188179, Feb 23, 1993

Dec 23, 1991

7/813195

Richard J. Gay - Houston, Harris County TX
Charles C. Gay - Bellville TX
Veronique M. Matthews - Austin TX
Francoise E. M. Gay - Houston TX
Valerie Chase - Houston TX

E21B 4102, C23F 1116, C23F 1118

166310

A system and method for inhibiting corrosion of oil field pipe exposed to corrosive material including hydrogen sulfide, carbon dioxide, and sodium chloride with a corrosion inhibiting film which is a precipitate film formed by the reaction of a polysulfide with ferrous iron. The ferrous iron may be a constituent of the fluid passing through the pipe or separately injected. The polysulfide is the reaction product of hydrogen sulfide as a constituent existing in the passing fluid and an oxidizing agent such as ammonium nitrate separately introduced into the passing fluid. The method includes the steps of continuously passing a fluid carrying corrodents through the pipe, continuously bringing a polysulfide into being within the fluid, and continuously bringing elemental ferrous iron into reaction with the polysulfide within the passing fluids to form a precipitated film which is an effectively amorphous film having a predominant amount of iron disulfide. The dissolving and abrasive characteristics of the passing fluid tends to continuously remove the amorphous film and the continuous reaction of the polysulfide with the ferrous iron continuously replenishes the amorphous film with an equilibrium state of removal and replenishment being established in time. Where there is an absence of hydrogen sulfide in the passing fluid, a polysulfide such as ammonium polysulfide or potassium polysulfide may be separately introduced in lieu of the oxidizing agent.