A contract to supply and operate a floating production vessel for Ranger Oil's Espoir development offshore Côte d'Ivoire is helping Nortrans Offshore break out of its North Sea-only envir-onment. Nortrans Offshore is extending its reference list of floating production, storage, and offloading (FPSO) vessels with the contract.
Also, the contract represents a technical breakthrough for the Singapore-based company and its strategy of becoming an FPSO contractor for all segments of the market, according to CEO Hans Hvide. The Espoir FPSO is scheduled to arrive on the field in the fourth quarter of this year.
The vessel will be moored in about 120 meters of water using an internal turret with capacity to accommodate up to 10 risers. The vessel will have production capacity of 40,000 b/d of oil, water injection capacity of 60,000 b/d, gas compression capacity of 60 MMcf/d for gas lift and gas export, and oil storage capacity of around 1 million bbl.
Long lease or purchase
The $300 million contract includes the lease and operation of the FPSO for an initial term of 10 years, with options for up to a further decade. Ranger may also opt to purchase the vessel outright during the initial term. Nortrans, which is listed on the Oslo Stock Exchange, has acquired White Sea, a 1975-built 155,000 dwt crude oil tanker, for the conversion.
The company has been operating since the early 1980s, converting tankers into FPSOs and floating storage systems. Its first delivery for Ranger was the Petroleo Nautipa, which it currently operates on Ranger's behalf on the Kiame Field off Angola. The vessel is spread moored in 142 meters water depth. Nortrans' current fleet includes two floating storage and offloading (FSO) vessels, which employ its in-house developed Normoor single anchor-leg mooring system:
- Endeavour, based on Hardy's PY-3 Field off India
- Madura Ayu, operating for Kodeco Energy in Indonesia.
Fluid swivel technology
Espoir's vessel represents a breakthrough as it will incorporate all the technology developed by the company during its existence. One of its focuses in recent years has been on fluid swivel technology, resulting in a compact swivel claimed to be around half the size of competing products. "We think the design is really revolutionary, in terms both of its compactness and the sealing technology," Hvide says.
The vessel will be fitted with an internal turret fitted in the bow. Given that conditions off Cðte d'Ivoire are not harsh, this decision (on Ranger's part) was driven chiefly by safety considerations with respect to offloading and the fact that the number of mooring lines are substantially fewer in the field. Compared with the alternative of a spread-moored system and separate single-point mooring buoy, it does entail an incremental capital expenditure. However, maintenance and operating costs are reduced.
Two wellhead towers
Nortrans' scope of work on Espoir extends to engineering for the flexible flowlines that will tie the two wellhead towers - to be located in the field's east and west - back to the floater. During the production phase, the company will also be responsible for operating these towers. Its engineering brief includes all risers and ends at the pipeline end manifold, which will connect the gas export riser to the gas export pipeline.
Nortrans has so far been involved on small- or medium-size field developments. It is now looking toward larger-scale FPSO projects with complex topside systems and multiple subsea centers, which would also justify employment of a newbuild vessel. To this end, the company has developed its own design based on its range of operating experience to date.
