A low oil- and gas-price environment encourages efficiencies. Spurred by the need to deliver more value at a lower cost, designers of deepwater production systems are examining ways to modify current designs and existing assets. The goal is to create systems with a broader range of capabilities and applications in a bid to provide units that offer unique value.

Increased activity in the fixed and floating systems sector has given operators enough confidence to move forward with programs that have been tabled for the last couple of years. January 2017 saw the first signs of resurgence, with the oil price hitting $55 for the first time in 18 months. The price stayed above $50 for the first quarter, and as the industry turned the page to 2018, things still appeared to be improving. Brent crude futures held above $70/bbl and West Texas Intermediate crude futures were at $66.24/bbl at the end of January, achieving a level analysts say has resulted in the strongest oil price in five years.

Across the board, analysts and investors are predicting a resurgence in deep water. And that means the time is ripe for reevaluating some of the novel concepts designed for deepwater production and examining some new ideas that are in development.

Something old, something new

Several of the production units that are preparing to go to work now are moving out of the inactive fleet. One of these is the BW Adolo FPSO vessel, which will work on the BW Energy-operated Dussafu project offshore Gabon following modifications at the Keppel FELS shipyard.

The interesting thing about the BW Adolo is that it began life as a very large crude carrier (VLCC) called Fina Europe, which was built in the Hyundai Heavy Industries (HHI) yard in South Korea in 1988. The VLCC went through several names over the ensuing years, eventually being converted and renamed yet again in 2009 to become the Azurite, the first floating, drilling, production, storage and offloading (FDPSO) unit in the world.

The vessel made history when it began production on the Murphy West Africa Ltd. Azurite deepwater field in the Mer Profonde Sud Block offshore Republic of Congo. With a storage capacity of 1.3 MMbbl of oil and processing capacity of 40 Mbbl/d, its unique design allowed it to be used for drilling and completing production and injection wells. Unfortunately, Murphy shut down the Azurite Field in fourth-quarter 2013 and abandoned it the following year, which left the FDPSO unit without a contract. It has not had a contract since that time.

Making its most recent debut as the newly updated and renamed BW Adolo, the vessel, now an FPSO unit, is going back to work. Following modifications at the Keppel yard in Singapore, the vessel features large riser and storage capacity, excess processing and heating capacity and large accommodations and deck space for future field expansion. The newly modified FPSO unit will soon begin production on the Dussafu Field, which, though not a deepwater development, will be produced using this deepwater production system. First oil is planned for second-half 2018.

First to float LNG

Another of the assets entering service is Golar LNG’s Hilli Episeyo. Golar was a first mover in the floating LNG (FLNG) space, building the world’s first converted FLNG unit using the Moss LNG carrier, Hilli, originally built in 1975. The conversion was carried out by Keppel FELS in Singapore.

While the vessel was still in the Keppel yard, it was part of another first as the recipient of the first commercial LNG bunker transfer in Singapore when FueLNG, a Keppel FELS/Shell Eastern Petroleum Pte Ltd. joint venture, completed truck-to-ship bunkering for the vessel.

In late 2017 Golar reported that conversion and precommissioning work on the vessel were complete. The FPSO unit left Singapore in mid-October and arrived in Cameroon toward the end of November, where it will begin work on the Kribi Field for Société Nationale des Hydrocarbures and Perenco Cameroon.

Innovative concepts

In addition to units about to take the field, concepts are on the design table. R&D efforts are delivering more technologies with the potential to improve drilling and production, and more designs are targeting greater efficiencies.

One of the ways designers move novel ideas from concepts to the field is by getting third-party approval from classification societies. Class societies provide a thirdparty assessment of the design and award Approval in Principle (AIP) for those that are deemed feasible— defined as having no significant obstacles that would prevent the concept from being realized. Normally, this assessment takes place in the early stages of a project to confirm feasibility for the project team, company management and regulators. Recently, a number of AIPs were granted for designs that introduce some impressive new capabilities and efficiencies.

Last year HHI was awarded AIP for an FLNG design that the company said can be constructed for about half the cost of a standard FLNG hull. The design introduces a vessel with a length of 320 m (1,050 ft), a breadth of 60 m (197 ft) and a 12-m (39-ft) draft with LNG storage capacity of 200 Mcm (7 MMcf) using the GTT MARK III membrane technology. According to HHI, the near-shore FLNG hull concept design delivers an estimated one-third cost reduction compared to a standard FLNG hull.

HHI applied the same thinking to a newbuild conversion FPSO hull concept that was awarded AIP in January 2018. The company’s Newbuilding Conversion FPSO hull also introduces economies, according to HHI. The company said the hull can be built for about half the cost of a conventional FPSO hull. The unit, which features structural reinforcement for topside structure installation, has a barge-shaped hull and is intended to store 2 MMbbl of oil.

Late in December 2017, Dalian Shipbuilding Industry Co. was awarded AIP for its DSTLP500 deepwater tension- leg platform. The unit, which features four pontoons, four columns and eight tendons, is designed to work in 500 m (1,600 ft) water depth, primarily in the South China Sea.

Fast, flexible construction

Meanwhile SBM Offshore is moving forward with what it calls the Fast4Ward (F4W) hull concept, motivated by the belief that reduced complexity and shorter schedules are the key to achieving better safety and economics. The company, which has been developing F4W since 2014, introduced the concept in August 2017 as a faster, cheaper and safer way to reach first oil. The design focuses on standardization, modularization and flexibility. The intent is to deliver what SBM calls maximum interchangeability.

F4W is based on a generic hull designed such that it is ready to receive and integrate topsides modules and a mooring system. It has large capacity storage, deck space to accommodate complex topsides and construction that requires a single quay. According to SBM, a unit can be completed six to 12 months faster than the typical three-year schedule for a third-generation FPSO unit and at a lower cost.

In June 2017 the company signed a contract for the first standard newbuild, multipurpose hull with China Shipbuilding Trading Co. and the Shanghai Waigaoqiao Shipbuilding shipyard.

Challenges bring opportunities

While the oil and gas industry has struggled through an extended downturn, many companies have looked for ways to deliver new designs that deliver economies and capabilities to sustain oil and gas E&P. Innovative thinking has led to designs that could significantly impact economics, and even more inspired designs are still on the drawing board.

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