Moving LNG production to an offshore setting certainly presents a serious set of challenges for the offshore oil and gas industry, particularly when it comes to the design and construction of FLNG facilities which need to maintain the utmost levels of safety and give increased flexibility to LNG production while withstanding the effects of winds, waves and currents in the open seas. With the first FLNG plants now in production and twenty other planned FLNG projects worldwide, it is safe to say that over the past few years these challenges have been overcome and these facilities have well and truly demonstrated their economic and technical viability to the industry. But while some challenges have certainly been met, others remain.The environmental conditions of the current FLNG locations are at present quite mild and only require the use of the most straightforward technology for the unloading of the LNG, e.g. marine loading arms. But, with prospective new FLNG locations moving away from these 'mild' areas, to sites where sea states, wind and currents can be much more severe, only tandem LNG offloading systems appear to meet the challenges of the application as they improve safety, operability and availability.Since 2009, Trelleborg has been developing floating cryogenic hoses which ensure LNG offshore transfer with minimum BOG generation, combine high flexibility, reliability and long service life, and also meet LNG operator and contractor's offloading requirements related to safety, flowrate capacity and operation availability. Through latest acquisition, this technology has been even further enhanced, with new parameters being put forward for the development of these hoses in order to become a key component in offloading systems for future offshore FLNG projects.This white paper will discuss Trelleborg's 20Љ ID cryogenic hose development and qualification program and outline why tandem offloading solutions are a viable alternative for the industry -not only limiting downtime, but also improving safety. The paper will present in this case the innovative offshore LNG offloading system using cryogenic floating hoses which has been jointly developed with Saipem since 2009 and about to be qualified according to EN1474 standard requirements.

This paper presents the extensive work performed to propose to the LNG industry an offloading solution fully compliant with EN1474 standard requirements using floating hoses. Between 2009 and 2013, a tandem offloading system using floating cryogenic flexible hoses developed and qualified to be able to transfer LNG in open seas. This arrangement was selected in order to combine the safety and the availability brought by the tandem configuration with the wide operational envelope provided by the use of floating hoses. This system is composed of an innovative and compact hose storage system on the LNG Terminal allowing to store the hoses between two offloading operations, of a connection head (hose end termination piece) to ease the deployment/retrieval of the hoses and of a storage and maintenance platform for the connection head at the aft of the LNG Terminal, also allowing to replace a hose section in offshore conditions. On the LNG Carrier side, a bow loading platform is installed to ensure hoses connection even in exposed environmental conditions. The 20" ID cryogenic floating hoses to be used with this system has been developed and qualified in parallel with the development of the tandem system. A red line for this development was to keep a similar level of safety, integrity and performance to onshore offloading operations. To fulfill this requirement, simple, robust and proven technologies have been considered for the main items of the system. The system incorporates a comprehensive panel of safety layers through monitoring, hardware, procedures and control philosophy providing protection for people and material during all steps of the offloading sequence. Regarding the performance, the system can transfer LNG at a flowrate of 10, 000 to 12, 000 m3/h using three hoses, which gives redundancy to transfer LNG even with one hose unavailable. To offer a high availability, dedicated solutions have been implemented in the system to withstand sea states with Hs up to 3.5 m for hoses connection and 4 m for cargo transfer and hoses disconnection. This solution will help unlocking offshore stranded gas resources in many areas around the world through FLNG development.

Oil and Gas Operators are moving active production and injection equipment onto the seabed with the aim of reducing CAPEX and/or topside space requirements. Moreover, they want to minimize new production floating facilities (e.g. through tie-back to existing FPSO/Floaters). Given this scenario, the overall electric power needs may become an issue because of the extra power demand due to the increasing number of electric consumers placed subsea. These electric loads may include the subsea boosting (pumps or compressors) operations, pipeline heating or the typical subsea water, chemical injection and valves actuation (in the case of all electric control systems), just to mention some of potential subsea power consumers, and may exceed the existing FPSO/Floater power production capacity. A potential solution to overcome this issue consists of the deployment of wind generators combined with topside Island power generation. Offshore wind power is indeed more and more considered for shore power supply, but also by the Oil and Gas industry with the objective of reducing the carbon footprint of their facilities. High power marine wind generators are already consolidated technologies for near coast, and today they are evolving in the short-term to floating solutions for the open sea. Saipem has developed its own floating wind turbine solution, called Hexafloat, consisting in a pendular floating foundation made of tubular elements and connected through tendons to a counterweight. This solution is particularly cost-competitive for deepwater locations (thanks to the low mooring costs) even for harsh environmental conditions (thanks to an excellent stability), and will unlock the possibility to deploy large wind power generators far from the coastline in deep water. The system composed by the Hexafloat base and the wind generator may be equipped with onboard back-up generation utilities to provide continuous power supply for subsea, despite wind intermittency, and to provide support to certain subsea field development services, making the assembly a kind of supporting device for the subsea field or for the FPSO. This is the Windstream concept that is under internal development and that will be better described in the present paper through the explanation of the results achieved within a couple of case-studies analyzed.

Moving LNG production to an offshore setting presents a demanding set of challenges. Along with the design and construction challenges of developing FLNG facilities, extra thought has been required regarding the transfer of the product; LNG transfer must now battle with the effects of winds, waves, and currents in open seas. In environments where conditions are much more demanding, conventional marine loading arms will not suffice as they could result in a shut-down of the liquefaction plant in bad weather conditions. This paper outlines why tandem offloading solution that rely on the use of flexible hoses are a viable alternative for the industry -not only limiting downtime, but also improving safety. Hydrodynamics analyses have been performed to demonstrate that the performances of such an offloading system are in compliance with targeted environments and associated operating envelope. Key results of this study will be introduced here. This paper will also discuss why -in the absence of mature solutions -different actors have been joining forces to develop and qualify an innovative LNG tandem offloading solution using floating hoses that fully satisfies the industry's requirements. It will be shown how the joint industrial program has been benefiting from diverse inputs coming from an IOC, an EPC contractor, a hose manufacturer and a University laboratory specialized in flow assessment.Finally, as an illustration of such a successful JIP, significant information will be given about pressure drop analysis within a flexible cryogenic hose based on advanced CFD models and small scale water/LNG flow tests.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractIn deepwater, corrosion protection of flowlines is becoming a major issue as fluid (production or injection) aggressiveness, temperature and pressure increase. Conventional corrosion allowance of carbon steel flowlines leads to excessive procurement costs, installation weight and welding thickness resulting in non economic solutions. Clad flowlines present excellent corrosion protection, but the implementation of this technology results in quite expensive solutions with additional NDT difficulties during installation.An interesting alternative to achieve an acceptable corrosion protection in most conditions is the use of plastic liners. However, plastic lining has been mostly limited up to now to reel lay. Transposing as such this technology to J-lay results in a complex quad joint design inducing more welding and NDT difficulties at every offshore joint. Therefore, the use of this attractive technology in J-lay implies the development of a specific field joint design. SAIPEM SA has developed and patented an innovative and cost effective field-joint system (the Inconel Field Joint). This system maintains the corrosion barrier across girth weld locations along the flowline. This technology has minimal impact on the offshore laying rate due to performing standard steel to steel welds. It is associated to an integrated lining solution including all piping accessories by rotolining. This paper presents the main characteristics of the IFJ system for a typical deepwater water injection application and discusses the results of the extensive qualification program carried out over the last two years, including swage lining, machining, sleeve insertion, leak test and welding tests.