Casing failures caused by external corrosion attack led to an engineering study to obtain design data and costs for a multiple rectifier type cathodic protection system for 48 wells. This protective system was subsequently installed in an effort to prevent further costly casing repairs.
Difficulties encountered in obtaining the desired current drain of 1.5-2.0 amperes from each well and solutions to these problems are discussed. In final form the multiple rectifier installation provided all protective current for approximately 75 percent of the wells, while magnesium anodes were used exclusively or in supplement to rectifier drainage for the remainder.
All of the coated gas lines, an appreciable portion of the bare oil gathering lines, and most of the production storage tank bottoms in the field were necessarily included in the cathodic protection system. In addition a separate rectifier-graphite anode system with new design features was installed for protection of an emulsion treater and brine handling equipment associated with a waterflood project in the field. 5.2.1
