One of the North Sea's current projects - due to produce first oil soon - uses a combination of strategies with key contractors and suppliers in a novel way to bring back production from a field which produced the first oil on the UKCS.

Argyll was the first oil field onstream in the UK sector of the North Sea on June 11, 1975, via a floating production facility (FPF) operated by the Hamilton Brothers.

It became uneconomic after producing 100 million bbl of oil and ceased production in 1992 when BHP was operator. The FPF was removed to shore and production wells were abandoned.

Now Tuscan Energy, along with partner Acorn Energy, is due to bring Argyll back to life, as the new Ardmore development, in block 30/24 in the Central North Sea.

Four new wells are to tap the field. There will be no FPF this time. Instead, one of the world's largest jackup rigs, the Rowan Gorilla VII, is being re-equipped as a mobile offshore production and drilling unit.
Electric submersible pumps (ESPs) will provide artificial lift, and the Expro Group designed a purpose built modular production process package. McNulty Offshore installed the package at its fabrication facility in northern England mid-summer after Steel Services in Grea Yarmouth built and delivered the process train.

Coincidentally the Expro Group, which is now playing a key role in the re-development of Ardmore, was in at the outset as the production-test contractor when Argyll was first discovered.

"Expro were involved in bringing ashore the first oil from the Argyll field," Raj Lekhy, manager of Expro's production solutions group, said. "Our company will be celebrating its thirtieth anniversary this year, so the start-up at Ardmore will be a double milestone."

Tuscan will lease the production package from Expro who will both own and operate the processing system, after winning a US $25.5 million turnkey deal to supply production facilities in October last year.
"We will stabilize and condition the crude prior to pumping it to Tuscan's tankers which will be direct loaded via one of the two mooring buoys," Lekhy said. "Our contract with Tuscan is for the design engineering, procurement, installation, commissioning, operations and maintenance services for a potential 5-year term."

First oil from Ardmore is scheduled for later this year, possibly in September.

"Our process plant has been specifically designed for Ardmore crude," Lekhy said. "However there is flexibility in the package design to cater for the production profile throughout the field life. Beyond that, it can be adapted for alternative operating parameters if required."

Process equipment on the Gorilla 7 will be specified for maximum throughput of up to 60,000 b/d of liquids - 40,000 b/d of oil maximum or up to 50,000 b/d of water maximum. First stage separation pressure is between 225 and 300 psi (15 and 20 bar) and fluid temperature is up to 247?F (120?C). Ardmore oil is described as a light sweet crude, with an API rating of 101?F (39?C).

"The challenge is to design a safe and modular system that meets the requirements of the export system," Frank Skilbeck, engineering manager on Expro's Ardmore team, said. One of the challenges was producing a process package to fit a facility carrying out concurrent drilling operations.

Once agreed, the final design featured a two-layer deck, with second stage separators above export pumps and coolers. A control unit takes data from the process package, ESPs and power generation equipment on the rig, so that technicians can keep equipment operating at optimum.

All of this has been happening while certification authority Det Norske Veritas (DNV) acted as the independent competent person to ensure compliance with latest engineering codes and standards - essential if the topsides safety case is to obtain UK Health and Safety Executive approval.

But further complication has arisen with the introduction of a new European Community Pressure Equipment Directive (PED), which came into force in 2002. All Ardmore equipment has to be proven to comply with the PED.

Previously, individual countries had their own pressure equipment engineering standards to adhere to. In the United Kingdom, it was BS 5500. Now, all European countries have to comply with a single European standard to obtain the necessary Certificate European (CE) kite mark, found on most manufactured products in Europe. DNV has had to ensure Expro complies with the PED standard. Every piece of equipment within the Ardmore process train has to comply with PED, both individually and as part of the system. The onus has been on Expro with DNV to prove it to the satisfaction of the HSE, adding a further challenge to the fast-track project schedule. "It has been a very detailed approval process," Lekhy said. This sounds like an understatement.

In July a new Atmospheric Explosives (Atex) directive has also come into force, specifying standards to which equipment operating in explosive environments has to comply. This has added another complexity. "It has been a steep learning curve - in many ways Expro is setting the precedent for applying the new rules to future projects," said James Evans, health, safety, environment and quality control manager for the Expro engineering team.

All equipment has to be proven as fit for service under the new regulations to the satisfaction of DNV and the HSE, he said.

Lekhy concluded, "Tuscan's innovative approach to marginal field development is very much in line with our own."

He added that if process facilities can be put together and operated for a price that makes a field economic, there should be a bright future for marginal projects and early production systems.

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