Re-Floatable Towed Production Systems for Small Pool Development

Abstract The Re-floatable Towed Production System Program was instigated to develop a methodology for re-floating, re-positioning and re-installation of a subsea system for marginal fields/small pool developments. The Towed Production System incorporates either small or large subsea processing manifolds/towheads at the ends, connected together with a Pipeline Bundle. This provides a complete subsea system installed in a single offshore operation. When installed, a towed production system is ballasted for added on-bottom weight to withstand operational, environmental, and trawling impact loads. To achieve this weight the annulus of the bundle is filled with treated seawater while the main structural members of the towheads are filled with a combination of barite slurry and seawater. This paper will examine the methodology to remove this added ballast in order to re-float the entire system. The ability to re-float a towed production system unlocks the notion of re-using subsea infrastructure. While historically Pipeline Bundles have shown to be configurable for specific field applications, a standardization of the Pipeline Bundle and integration of subsea processing, as used within this study, can enable the asset to be used over multiple field locations. This includes, but is not limiting to, the use as a development tool for small field exploitation. This will add value to the system as a cost-effective solution for subsea field developments. A key to the re-use of subsea infrastructure is integrity monitoring, including the demonstration that after re-positioning the product it is fit for purpose with sufficient remaining design life. The paper will also detail the related development work conducted on fibre optic monitoring within the Pipeline Bundle section.