Abstract
Shell is the world's largest international oil company by equity LNG production with ownership in many liquefaction projects currently in operation or under construction. Now floating liquefied natural gas (FLNG) is set to drive the next major shift for Shell and the LNG industry. FLNG technology allows for the production, liquefaction, storage and transfer of LNG at sea, as well as the ability to process and export liquefied petroleum gas (LPG) and condensate. This enables more gas fields to be developed which would otherwise be economically challenged and will bring more natural gas to market.
Shell's final investment decision (FID) for Prelude in May 2011 was the world's first FID for a FLNG project. Shell is the operator of Prelude FLNG in a joint venture with INPEX (17.5%), KOGAS (10%) and OPIC (5%). The facility is being built by a consortium of Technip and Samsung Heavy Industries (SHI), with the Geoje yard in South Korea being a key construction location.
The development of FLNG is complex. Shell has been working on FLNG technology since the mid 1990s drawing on more than five decades of expertise in LNG technology, LNG shipping and operating offshore facilities. Shell's approach to FLNG is to design for safe, high availability and reliabile production using proven technologies. The constraints of space and seaworthiness however, required the designers to assemble these technologies in novel configurations. Examples include the internal turret -suitable for tie-back of complex subsea systems and harsh meteocean conditions, a double wall substructure hosting the product storage tanks, processing equipment that has been modified to allow it to operate efficiently under marine conditions and specially designed cryogenic loading arms able to operate in a dynamic offshore environment.
The safety of the FLNG facility has been foremost during its design. The topsides layout has been developed using Quantative Risk Assessments and rigorous process safety standards. The layout also includes 20 meter safety gaps across the full width of the FLNG barge between the main processing modules with escape routes along both sides of the facility, as well as through the central alley.
Shell is applying standardisation as a philosophy for its FLNG design, so that developments can become faster and more cost effective. Based on this philosophy, we have also developed a FLNG solution designed for leaner gas fields that has many similarities when compared to the standard FLNG design. The so called ‘FLNG Lean' can be applied on fields with lower liquids yields and, by optimizing liquid handling and storage facilities, FLNG Lean is able to deliver higher LNG production capacities.
