Protective Coatings for Corrosion Control in Production Operations

Abstract

Introduction Coatings are used in production operations for identification purposes, for appearance and for corrosion control. The role of coatings as a corrosion-control measure in production operations has become an increasingly important one during the last several years. There are a number of reasons for this, the primary one, of course, being costs. Labor and equipment-replacement costs have risen sharply during the past decade, but the price of the prime product, oil, has not risen accordingly. Another reason for increased use of coatings is the presence of severer corrosive environments such as those encountered in offshore operations. Also, more operators have become aware of the savings and benefits to be gained from the proper selection and use of coatings. When used for corrosion control, coatings serve as barriers to separate the metal from the corrosive environment. In production operations, the corrodents and physical conditions are almost innumerable. Consequently, a myriad of coatings and coating types have been offered to the industry, and new ones are being marketed almost daily. Many tapes and sheathing materials also are available for use as corrosion barriers. Tapes and sheathing materials are discussed later in conjunction with the services for which they are used. Present-day coatings belong to many generic types. Some "dry" by solvent evaporation, some dry by oxidation while others dry, or "cure", by polymerization. Oxidation or polymerization may be catalyzed by chemical additives or by baking at elevated temperatures. Relative resistances of the coating materials vary greatly between, and even within, generic families. Therefore, it becomes the corrosion man's problem and responsibility to select the proper coating for a particular corrosive environment.