Tullow Oil’s Tweneboa-Enyenra-Ntomme (TEN) deepwater development is something of a breath of fresh air in today’s thin E&P atmosphere—it’s on time, on budget and well on the way to becoming the operator’s second world-class field offshore Ghana to come onstream.
Expected to begin flowing oil during third-quarter 2016, the $5 billion project is nearing the 90% completion mark and recently saw its FPSO vessel, named Prof. John Evans Atta Mills after the country’s late president, arrive in Ghana after setting sail from Singapore in January this year.
The 300-MMboe field’s startup is well-timed not only for Ghana but also Tullow itself, with CEO Aidan Heavey saying earlier this year that the startup will allow the company to cut its net debt of $4 billion, having already substantially cut its capital spending in response to the sustained low oil price.
Once flowing, production is initially expected to average about 23,000 bbl/d for 2016, with Tullow holding a 47.18% stake as operator. Its partners are Kosmos Energy (17%), Anadarko Petroleum (17%), Ghana National Petroleum Corp. (15%) and PetroSA (3.82%).
The FPSO conversion itself has gone remarkably smoothly, taking 26 months to complete at the Sembcorp Marine shipyard. According to Andy Smith, Tullow’s FPSO delivery manager, “You’re not just looking at an FPSO here. You’re looking at 17.5 million man-hours. You’re looking at 18,000 tonnes of topsides. You’re looking at a 4,200-tonne turret.”
Roland Whitton, Tullow’s construction manager, added, “The turret is the biggest external turret that’s been built to date, so it dwarfs even the Jubilee FPSO [unit] that’s out in Ghana. It has an 11-m [36-ft] diameter bearing, which again is the biggest that’s been produced so far.”
Floating production specialist Modec supervised the build and will own and operate the leased FPSO itself.
According to Jeff Knox, Modec’s project manager, “The collaboration with Tullow from the Modec perspective has been a big part of the success on this project. The level of completion, the level of quality [and] the level of collaboration on this project is like none other. [Tullow] really got on the ground with Modec; they set up their team, and from that point onward it was a fairly seamless organization between our team and theirs.”
Low Operating Costs
If all continues as smoothly as it has done until now, the project will add significant low-cost production to Tullow and its partners’ portfolios. All these companies are focused on keeping operating costs low, as has been done on the Tullow-operated Jubilee Field offshore Ghana, where the operator said operating costs average $10/bbl (and $15/bbl across its West Africa nonoperated portfolio in 2015, according to its full 2015 annual results earlier this year).
Although that is already top-tier performance for a deepwater remote floating production project, Tullow stated in its results analysis that it is working toward maximizing operational synergies between the Jubilee and TEN developments “where combined operating costs are expected to reduce to circa $8/bbl in 2018.” TEN is located about 45 km (28 miles) from the main coast and 20 km (12.4 miles) from Jubilee, which came onstream in December 2010.
The industry environment has of course changed dramatically from when the plan of development for TEN was approved by the Ghanaian government in May 2013, just over four years after the Tweneboa-1 discovery well had been drilled by the Eirik Raude semisubmersible rig in the Deepwater Tano license. The oil price was around the $100/bbl mark, and there was little sign of the impending plunge that was to come the following year. But in such times, disciplined and well-run projects show their mettle—and TEN will still deliver on the bottom line for its participants despite the current price.
Eleven development wells have been drilled so far, with the completions campaign progressing well and the subsea production equipment installed on location during third- and fourth-quarter 2015.
The subsea installation campaign began in July last year and involved 35,000 tonnes of equipment being installed on the seabed, with the first kit installed being the FPSO unit’s nine 21-m (69-ft) high steel cylinder anchor piles. These were fabricated in Ghana and installed by the Normand Installer.
The majority of the subsea equipment was installed by the Technip-Subsea 7 consortium using the Seven Borealis and Simar Esperanca vessels, including the installation of three manifolds on Enyenra, one on Ntomme and oil production riser bases on Enyenra and Ntomme. Subsea 7 constructed a new fabrication base in Sekondi to fabricate anchor piles for the subsea manifolds.
FMC Technologies fabricated the subsea infrastructure, including the manifolds and christmas trees, with the components for the trees made in Houston but the kit assembled and tested at FMC’s custom-built 6,000-sq-m (64,583-sq-ft) facility in Takoradi, Ghana— the first time this process was carried out in the country. Each tree weighs about 40 tons.
In the final batch of fieldwork, the last of TEN’s 60 km (37 mile) total length of umbilicals connecting the FPSO unit to the subsea equipment were due to be installed by the Deep Pioneer, with the flexible risers being installed by the Deep Energy.
According to Tullow’s development schedule, the installation of the umbilicals and risers will be completed in June, with first oil lightly penciled in for July or August followed by final commissioning.
After a gradual ramp-up of production over the first few months, plateau production of up to 80,000 bbl/d of oil is expected to be attained early in 2017.
Tullow stresses that it has been committed throughout to maximizing local content.
This led to significant work being completed in Ghana, the company said, including construction of the FPSO unit’s module support stools and mooring piles and the fabrication of the subsea mud mats, all by domestic companies.
That experience is likely to be put to further good use as Tullow continues to—cautiously—progress its plans for the Greater Jubilee development. A full-field development plan for the Greater Jubilee area in the West Cape Three Points Block, including the Mahogany and Teak discoveries, was submitted to the Ghanaian government in December last year, with approval targeted by mid-2016.
Tullow is not the only active developer in Ghana, with Eni perhaps most notably busy with its ongoing FPSO project in the deepwater Offshore Cape Three Points (OCTP) Block, sanctioned in January 2015. First oil is expected from OCTP next year, with gas production to follow in 2018, initially from the Sankofa and Gye Nyame fields.
But it is the Irish independent and its partners that perhaps deserve a mark of 10 out of 10 for continuing to pioneer the development of Ghana’s fledgling offshore sector during the toughest of times.