Direct Electrical Heating Closer to Subsea Structures

Direct electrical heating is a qualified method for flow assurance in coated oil and gas flowlines. A concern is ac corrosion on connected templates caused by stray currents from the DEH system. This has prevented DEH from being installed on flowlines with in-line templates and restricted heating of flowline sections near the end templates. Solutions to limit stray currents have been verified by full-scale tests. The results confirm a reduction in stray currents through templates to 3 % of the supply current by installing laminated iron cores on the heated flowline.