Innovations in a submarine piggyback pipeline project in the East China Sea.

Abstract

Submarine pipelines are widely used to transport offshore oil and gas. Bundling service pipes and cables with these pipelines can cut costs but such ‘piggyback’ installations can lead to problems with torsion and buckling, particularly at crossings. This paper reports on an innovative anti-rotation device that was successfully implemented in a piggyback pipeline project in the East China Sea. A three-layer concrete mattress together with secondary pipe protection devices was developed for crossings, and advanced engineering analysis was conducted to evaluate risks from shallow gas eruptions.