The article reports that DeepSea Engineering & Management Ltd. has developed approaches to improve performance of gas pipelines using pipe-in-pipe (PiP) systems. As more multiphase hydrocarbons are produced from deepwater fields and transported long distances, flow assurance becomes more critical. Flow assurance requires management of a range of factors from hydrates, waxes, paraffin and asphaltenes to scale, corrosion, sand/erosion, etc. The systems are thermally efficient, with extremely low U-values, reliable, and a proven technology for both shallow and deepwater systems that require a low overall heat transfer coefficient, but their increased cost and weight is a significant penalty in deep water. In waters 3,000 ft or deeper, and particularly with flowline lengths of 6 miles or more, substantial cost benefits can be achieved. It is compatible with all forms of pipe-in-pipe systems, and provides a simpler and less expensive field joint system. It also addresses three aspects of PIP systems, thermal performance, installation and structural reliability