Paper: Cathodic Protection of Oil Well Casings

External casing corrosion with resultant leaks is a problem of major economic significance in the oil and gas producing industry. Cathodic protection systems, where practically and economically feasible, provide a means of arresting external casing corrosion. Sound engineering of these systems includes assessment of the problem, determination of the feasibility of cathodic protection, and an economic study. If the decision is made to install cathodic protection, elements of design include determination of protective current requirements, ground bed requirements, rectifier specifications, and choice of auxiliary equipment. After installation, proper maintenance is a must to realize the maximum benefit from the investment. Several commercial services such as casing inspection tools and voltage profile logs are available to aid in both the assessment of the problem and the design of the system.