Failure Analysis

Stray Current Corrosion

Rarely seen in most producing wells, stray current corrosion refers to the induced, or stray, electrical currents that flow to or from the rod string. Stray current corrosion can be caused by grounding electrical equipment to the well casing or from nearby cathodic protection systems. Arcs originating from sucker rods leave a deep, irregular shaped pit with smooth sides, sharp edges and a small cone in the base of the pit. Arcs originating from the tubing leave deep pits with smooth sides and sharp edges that are random in dimension and irregular in shape. Stray current corrosion pits are usually singular and isolated in a row down one side of the sucker rod near the upsets.