Shell Oil Comapny

Byron Lee Newberry

Ronald Marshall Bass

Carl G Langner

David John Liney

Apparatus and method for electrically heating a segment of a subsea pipeline are provided. The annulus between the pipes electrically isolates the pipes, but at the ends of the segment the concentric pipes are electrically connected. The inner pipe may be thermally insulated. Electrically insulating water stops are provided to act as flood control barriers in the event the outer pipe is breached. Collars on seals around the water stops may help avoid electrical shorts and packets of super-absorbent may be in place to further reduce the risk of electrical faults.

Annulus for electrically heated pipe-in-pipe subsea pipeline

Methods are provided for installing an electrically heated pipe-in-pipe pipeline on the seafloor. Inner and outer pipe segments are formed and the inner pipe is coated and insulated. Coating may include sprayed polyurethane foam and insulating half-shells that are placed around welds. Epoxy is preferably coated on the inner pipe before other coatings. The segments are loaded on a lay barge and water stops are preferably installed in the annulus as the pipeline is formed. Water stops may be formed by placing a liquid polymer in the annulus and allowing it to cure.

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Edmond, OK, United States of America

Byron Lee Newberry