In deepwater offshore fields where spread moored FPSOs are involved, theproduced oil is generally offloaded to shuttle tankers via Oil Offloading Lines(OOLs) connected between the FPSO and deepwater buoy. Until recently, two typesof Oil Offloading Lines (OOL) were used for the transfer of stabilized crudeoil between the FPSO and the offloading buoy: steel pipe or unbonded flexiblepipe. Since 2000 Trelleborg and SBM have been working on an alternativeoffloading solution made of bonded flexible hoses called TRELLINE™ (seereference [1]). This product can be adapted to a large range of applicationslike for the offloading of oil from a MOPUstor to a submerged loading system(SLS). In September 2005, the TRELLINE™ was used for OOL for the first time for SNEPCOwho decided to supplement the existing Bonga OOL system with one 20" IDTRELLINE™ to match with ultra short delivery. In December 2006, the OOL wasinstalled with the SBM vessel Dynamic Installer (see reference [2]). In July 2008, Total Exploration Production Angola (TEPA) decided to use theTRELLINE™ for the 18" ID OOLs of the Pazflor field. For Pazflor, the producedoil is exported from the FPSO to the buoy located 1,856m away, via twoidentical 18" OOLs of 2,070 m long, made of 175 hoses sections each. The OOLsare connected to the FPSO and the buoy by the means of gimbal tables thatdecouple the tension and bending loading. Specificity of Pazflor Trelline hoseswas their hig desing pressure equal to 50 bars that had required intensivequalification and testing program, and making Pazflor export lines a" world-first". Based on past installation experiences on Bonga project (OOL) for SNEPCO in2006 and on Yme project (SLS) for Talisman Energy Norge in 2008, see reference[3]), a new installation method has been developed. A specifically designedpatented equipment was developed to ensure a safe and quick offshoreinstallation. It comprises:An A-Frame designed to upend individual hose from deck to the fireline.An assembly platform designed for vertical assembly of the hoses.A large deployment wheel ensuring the transition from vertical to horizontalof the OOL at the sea surface. In June 2011, the SBM vessel Normand Installer successfully installed the twoPazflor OOLs. The two OOLs were assembled and hooked up in less than 4 weeks(mobilizations included). The TRELLINE™ OOL system demonstrated its advantages in term of design, procurement cost, lead time, installation efficiency and operationaladvantages. It will further demonstrate maintenance advantages.

Talisman Energy Norge AS has awarded a contract to SBM Offshore for the re-development of the Yme field which is located in the Egersund basin in the North Sea. The re-development is based on a Mobile Offshore Production Unit (MOPUstor) with a subsea storage tank from which stabilized crude is exported via a Submerged Loading System (SLS).The SLS, which is a novel design, is a freely weathervaning loading system located directly on the seabed. The SLS consists of a subsea flowline fitted with a horizontal diverless connector at each extremity, and a gravity base with a rotating upper part linked to the export tanker through a 16" ID riser in a Steep Wave configuration. When disconnected, the riser is left on the seabed, and the end of the riser is connected to a messenger line which is terminated by surface marker buoys and a pick-up rope.Both the riser and the flowline are comprised of 12m Trelline™ bonded hose sections. The riser (or any hose section) is replaceable by way of a vertical diverless coupling connecting the gravity base piping and the subsea central pipe swivel.An acoustic transponder with heading sensor is fitted on the rotating part of the subsea swivel, and acoustic DP reference transponders are positioned on the seabed.The SLS system is hawserless because it is operated with DP Class 2 tankers which can stay on station up to the maximum specified operational seastate.The SLS was installed by SBM's Normand Installer in August 2008. This was the first major milestone in the MOPUstor system installation campaign. The size of the gravity base and the large number of bonded hoses (115 hoses for the flowline and 16 hoses for the riser) made it a challenging operation, not only offshore but also at the mobilization in port. The constraints onshore and offshore, the main installation steps and the methodology are described in this paper.

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