Abstract
Direct electrical heating is a flow assurance method for subsea flowlines.
This article considers direct electrically heated flowlines that were
installed at an offshore facility in 2004. In 2022, one of the piggyback
cables was successfully repaired. The root cause for failure was dielectric
breakdown of the transition joint between the feeder cable and the
piggyback cable because of high accidental axial compression forces.
The accumulated operation time from 2004 to 2022 was 450 days.
Fingerprints from commissioning were essential in fault location, and the
fault was pin pointed with an accuracy of a few meters. Investigations of
the XLPE insulation material showed that the cable was in a generally
good condition.
KEY WORDS: Direct electrical heating; flow assurance; repair; fault
location; operation record; prolonged lifetime
This article considers direct electrically heated flowlines that were
installed at an offshore facility in 2004. In 2022, one of the piggyback
cables was successfully repaired. The root cause for failure was dielectric
breakdown of the transition joint between the feeder cable and the
piggyback cable because of high accidental axial compression forces.
The accumulated operation time from 2004 to 2022 was 450 days.
Fingerprints from commissioning were essential in fault location, and the
fault was pin pointed with an accuracy of a few meters. Investigations of
the XLPE insulation material showed that the cable was in a generally
good condition.
KEY WORDS: Direct electrical heating; flow assurance; repair; fault
location; operation record; prolonged lifetime