OFFSHORE EUROPE

June 1, 2010
Statoil has approved a tieback plan by Eni for Marulk, its second operated project in the Norwegian sector and its first in the Norwegian Sea. Marulk, a 73 MMboe gas/condensate field in 365 m (1,197 ft) of water, will be developed through two subsea wells tied back about 30 km (18.6 mi) to Statoil’s Norne FPSO. Eni estimates the total investments at $674 million; start-up is scheduled for spring 2012.

Jeremy Beckman - London

Statoil approves tiebacks to Norne

Statoil has approved a tieback plan by Eni for Marulk, its second operated project in the Norwegian sector and its first in the Norwegian Sea. Marulk, a 73 MMboe gas/condensate field in 365 m (1,197 ft) of water, will be developed through two subsea wells tied back about 30 km (18.6 mi) to Statoil’s Norne FPSO. Eni estimates the total investments at $674 million; start-up is scheduled for spring 2012.

In the same sector, Statoil has decided to develop reserves on the Njord field’s northwest flank, under a program that should extend the facilities’ lifespan by a further two years. The flank, 6 km (3.7 mi) northwest of theNjord semisubmersible platform, includes two rich gas/condensate structures discovered in 2000 and 2007 (total reserves around 18.6 MMboe). Pressure here is higher than in Njord main reservoir, which means modifications to the platform. The $293-million scheme involves drilling two extended-reach wells from the platform into the flank with 8 km (4.9 mi) of well paths.

Limited wells deliver value

A review by Deloitte paints a gloomy picture of recent drilling activity on the UK continental shelf. The 12 exploration and appraisal wells spudded during the first quarter this year represent a six-year quarterly low, the analysts say, and the tally is 33% down on the equivalent quarter in 2009. Results, too, appear to be disappointing, with only Nexen thought to have made a discovery on the Deacon prospect.

Chart shows well numbers on the UK continental shelf in recent years (Source: Deloitte).

Last year was also a tough one in terms of wells drilled. Aberdeen-based Hannon Westwood identified just 49 wells across the UK shelf, compared with the 77 drilled during the vibrant days of 2008. However, the success rate last year was much higher, with 28 of last year’s wells appraising or finding new reserves.

Hannon Westwood rates the total of appraised and new technical volumes at 1.224 Bboe. This constitutes a 146% replacement rate, when set against the 836 MMboe produced across the UK shelf last year.

Well costs were typically 10% higher than in 2008, but toward the end of 2009, there were signs of rig rates easing, particularly in the southern North Sea. This cost reduction should lead to a recovery in drilling through the rest of 2010, the analysts believe.

UK gas base grows

Despite the early poor showing, the run of successes for UK operators has recently resumed. Dana’s exploration well in the southern gas basin on the Platypus prospect, for instance, has confirmed pre-drill expectations, with estimated potential reserves of about 130 bcf. The well, drilled by the TransoceanGSF Labrador, hit its target objective in a Rotliegend-age, Lower Leman reservoir.

In the same region, GDF Suez’s latest appraisal effort on the Cygnus field appears to have pushed prospective resources to over 2 tcf, says partner Endeavour.

And in the central North Sea, a well appraising a down-flank extension of the Stella gas/light oil/condensate field got the thumbs-up from operator Ithaca Energy. It confirmed the presence of hydrocarbons 500 ft (152 m) lower than in any previous well on the structure. Ithaca plans to move swiftly to a full-scale development of Stella and other satellites in the area, with a view to starting production in 2012.

In the far north of the UK shelf, Valiant Petroleum found oil with its first operated well, one on the East Tybalt prospect in license P1632. Initial logging data suggested 63 ft (19 m) of hydrocarbon-bearing reservoir – lower than expected – but a planned sidetrack may shed new light. Valiant still has seen enough to start thinking of a joint development in the area with its other properties, Helena and Banquo.

Buoy could unlock Helvick

Dublin-based Providence Resources has the widest range of interests of any operator in the Celtic Sea off southern Ireland, but not a drop of production. That may be about to change.

The company has agreed to work with Aberdeen-based Unmanned Production Buoy (UPB) on a solution for its marginal Helvick oil field in the North Celtic Sea basin. The UPB is a new-concept, self-contained, re-deployable system designed to produce reserves from single or multiple subsea wells, using flexible risers and an integrated production umbilical.

The system is undergoing testing via a program sponsored by the UK’s Industrial Technology Facilitator, using a 15-m (49-ft) model targeted at reserves as low as 500,000 bbl. In its current configuration, the UPB can handle 15,000 b/d of produced fluids, which can be accommodated in a 200,000 bbl subsea storage tank prior to offloading to tankers. Power is provided via three 0.85 MW dual-fuel gas/diesel engines.

Helvick is a long-stranded oil and gas field in license SEL 2/07 discovered by Gulf Oil in 1983, 40 km (24.8 mi) offshore southern Ireland in 80 m (262 ft) water depth. Providence estimates oil in place at 10 MMbbl, but says the field’s limited areal extent could assist recovery in a short time-frame, thereby improving the development economics.

Closer to the coast and in the same basin, Providence has farmed out a 40% interest in Licensing Option 10/1 to London-based Nautical Petroleum. The permit includes the heavy oil Baltimore discovery, which has potential resources of 300 MMbbl. Under the agreement, Nautical – which also has heavy oil interests in the UK North Sea – will fund a development feasibility program.

Power link for Ekofisk, Ula

Two of Norway’s leading operators are studying how to coordinate the supply of power to their development projects in the Norwegian North Sea. The Norwegian Petroleum Directorate (NPD) asked ConocoPhillips and BP to examine joint electrification options for the Ekofisk and Ula complexes. In the case of Ekofisk, this is connected with planned modifications and the addition of new platforms. On Ula, the power supply system will need to be replaced in the next few years.

Results from the study should be issued by the end of 2010. One of the main issues will be cost, NPD admits. NPD is pushing for more of Norway’s offshore installations to be powered by electricity from land, rather than through use of gas turbines.

Apache to expand Forties

Apache has commissioned Altra Energy for front-end engineering design for a new production platform at its Forties field complex in the UK North Sea. This would be the first new installation since previous operator BP added the Unity Riser Platform in 1993. Altra is performing engineering for the topsides and bridge link, in partnership with EPIC contractor SLP North Sea. Apache aims to complete construction and deliver first oil during 2012.

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