Corrosion by Anodic Interference Cell Formation, Stray Currents

4 Corrosion by Anodic Interference (Cell Formation, Stray Currents) 

Since in oilfields or reservoirs borehole casings are frequently sited close to one another, they can be affected by the voltage cone of the anode bed and the cathodic voltage cone of other casings. Thus, in the case of large oilfields and reservoirs, it is appropriate to protect all wells cathodically. 

3 Measurements for Assessing Corrosion Protection of Well Casings 

With buried pipelines, the degree of corrosion danger from cell formation and the effectiveness of cathodic protection can be determined by pipe/soil potential measurements along the pipeline (see Sections 3.6.2 and 3.7). This is not possible with well casings since the only point available for a measuring point is at the well head. Therefore, other methods are required to identify any corrosion risk or the effectiveness of corrosion protection. 

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