The development of the Udang "B" project in the Indonesian Natuna Sea required the installation of two insulated submarine pipelines in nearly 300 feet of water. These pipelines carry 100° F pourpoint crude, water, and gas from the recently installed Udang "B" platform to the Udang "A" platform. At the Udang "A" platform, the produced fluids are processed. The crude oil is then transported to a permanently moored storage tanker through two other insulated submarine pipelines.

The Udang "B" pipelines have a 12¾ inch inner pipe with an 18 inch outer pipe. The annulus between the two pipes is filled with a polyurethane insulating foam. That annular cavity is then sealed with a steel washer plate at either end of the insulated pipe joint. The pipeline system is designed to withstand a 190° F operating temperature and to comply fully with applicable pipeline codes. The pipeline is designed so that the polyurethane insulating foam is protected from the 140 psi external hydrostatic pressure.

The pipelines were installed offshore using a lay barge with innovative methods used at the field joints to insure the uniform structural integrity of the pipeline and the continuity of the insulation system. The risers were also insulated and installed in one piece with a flanged connection completed on the seafloor to connect the riser with the pipeline. Third party underwater inspection of the jacket, risers, and pipeline connections was provided by a remote controlled vehicle (RCV).

This paper discusses the insulated pipeline system as it evolved through the design, onshore pipe insulation and joint fabrication, and offshore construction. The paper reviews the design and construction techniques used successfully for these offshore insulated pipelines. These techniques could be applicable for other similar deep water insulated pipeline applications.

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