Archer's modular Topaz makes its North Sea debut

The Archer Topaz modular rig, as it will look installed on the Helmdal platform. Photo from Archer.

Archer’s new vertical drilling rig is due to debut in the Norwegian North Sea later this year. Meg Chesshyre found out more.

Drilling specialist Archer’s new VDD (vertical drilling rig) 400.2 offshore modular rig, the Archer Topaz, will be deployed for the first time in the Norwegian North Sea later this year. Carrying out plugging and abandonment operations on a modular rig is also a first for Archer and the industry as a whole.

The rig is in the final stages of commissioning at German rig manufacturer Max Streicher’s facility at Deggenau in Germany, and ready for transportation to Norway. The design and construction of the rig has been carried out over about 18 months.

“All of Norway’s oil and gas industry focuses on us,” comments Dr. Peter Romanow, head of drilling technology at Streicher.

The new rig is scheduled to mobilize for a program for Statoil, and partners Total, Centrica, and Petoro, in themHeimdal field in August, and to be operational by November. The contract is for permanently plugging and abandoning 12 gas wells on the Heimdal platform in the Norwegian North Sea. The contract period is 34 months, with four option periods of three months each. Total contract value, including the startup, operating and decommissioning phases, is estimated at US$115 million.

The low persons on boar (POB) required to operate the Archer Topaz made it a viable option for Statoil for

deployment on the Heimdal field center, where installation upgrades are under way to keep the field operational as a gas processing and distribution hub up until 2030. First gas from the nearby Valemon field, to be exported via the Heimdal platform, is expected this coming December.

The modular offshore rig, Archer’s second, has been designed and built in cooperation with Max Streicher and is in line with current NORSOK regulations, the standards developed by the Norwegian petroleum industry. It is easy to transport, install, and dismantle, and is highly automated. The rig up time is around three weeks and there is a self-erecting mast system. The pipe-handler operates fully automatically, the pipe-handling crane, which has been adjusted to the limited space on the Heimdal platform, is partially automated. The modular-designed pipe deck, with its support structure, weighs about 200-ton and can be loaded with rods and pipes up to 150-ton. The deck will be delivered in about 30 modules.

“The fact that it is NORSOK compliant means we can basically operate anywhere in the world at the highest level of safety,” explains John Lechner, president North Sea and executive vice president with Archer. The high level ofautomation results in a minimum POB and a much safer operation.  “It gives us the advantage of what you would see on a seventh generation semisubmersible, as far as automated handling and safety systems are concerned.”

He stresses the advantages of the modular system in terms of flexibility of operation.

“We believe this is a first class rig, safe and an efficient alternative to more conventional solutions for mature installations in the North Sea.” With a modular solution, the cost is low because the POB is low, and the cost of installing the rig is much lower than other solutions.

An unexpected additional benefit of the modular system arose, when there was major flooding in the Deggendau region last year, as the manufacturer was able to send some of the modules to other subsidiaries, in order to catch-up. It also means that testing and commissioning can be carried out in parallel.

It is easy to integrate the modular rig onto a platform and easy to re-use. There is no need to refurbish outdated platform drilling rigs in situ. The structure can be re-configured to reach other well slots. Its small footprint makes it appropriate for aging platforms with restricted space, and its integrated power generation and mud system allow for autonomous operations, Archer says.

The VDD 400 range features a 400-ton pull capacity, a 100-ton pushing capacity, a maximum 12-ton module weight, two direction skidding, and a compact 145 x 12m footprint, without power supply. The mast height is 28m and the drilling depth 5000m. The hydraulically driven VDD 400.2 has automatic pipe-handling for tubular sizes 2½-in. to 20-in., and is suitable for operation in hazardous areas. The hydraulic power enables precise control, and despite small components, high power can be transmitted. The rig and mud package weighs 490-ton, the power package 128-ton, and the pipe deck and pipe-handling crane 220-ton.

The new modular rig follows Archer’s first modular rig design, VDD 400.1, the Archer Emerald, which was a breakthrough when it was launched in 2012. The Archer Emerald is currently operating offshore New Zealand in the Tasman Sea on Shell Todd’s Maui A offshore platform. It successfully completed its first year without any LTIs (lost time incidents) in February.

The two projects differ in that for Maui Archer had to supply its own power, but was able to use an existing pipe deck, whereas on Heimdal a power supply is available, but it was necessary to supply a pipe deck. Lechner says there have also been some ergonomic learnings from Maui for Heimdal, in terms of maintaining equipment in a compact space offshore.

Archer’s modular rigs (MDRs) are designed to stand alone, can be rigged up on most offshore installations, and can perform most drilling operations normally performed from a platform, including drilling and workover operations, completions, snubbing services, casing drilling, and plug and abandonment, Archer says. They are rack and piniondriven, modular drilling, and intervention rigs, a concept proven by Streicher on land rigs in Europe, but a new concept for the North Sea.

This modular rig package can be tailored to meet well-specific requirements and provides operators with an alternative to both mobile offshore drilling units and traditional platform drilling rigs on existing and future installations. Using an MDR, in both greenfield and brownfield environments, negates expensive CAPEX investments and/or costly re-activation projects, Archer says. Renting an MDR also negates operating, maintenance, and re-certification costs on existing drilling facilities.

Archer secured a contract this spring for the provision of drilling services with Talisman Sinopec Energy UK using the Archer Emerald. This contract will be the first operation using the modular rig on the UK continental shelf. The initial two-year contract is worth about $96 million. Mobilization is due to start in 1Q 2016, following a period of rig interface modification. The platform-based modular drilling activity will form an integral part of the Talisman UK Montrose Area redevelopment project, aimed at prolonging the life of aging assets and extracting further reserves from the Montrose reservoir.

The Archer Topaz modular rig, nearing completion in Germany. Photo from Archer.

Lechner thinks that once both modular rigs are working in the North Sea in a year and a half’s time—one a piece in the Norwegian and UK sectors—“We’ll be able to showcase the technology, show that the work can be done with a very low POB, and to the safety standards that we are talking about.”

The modular rig suitability assessment comprises a desk top feasibility study, an offshore site survey verifying the findings of the desktop study, a FEED study, detailed engineering, and finally the offshore construction project, where engineering teams are mobilized to conduct the interface activities to install the MDR on the platform. This activity is conducted off the critical path, ahead of mobilization, to mitigate any exposure to delays during MDR mobilization.

Archer’s rig manager for the Heimdal project, Bjørn Christensen, says that Archer personnel are currently being trained up for Statoil’s Heimdal project. Archer has more than 8100 employees over 100 locations, including the North Sea, Middle East, Asia, Africa, Europe, North America, Gulf of Mexico, and South America. In addition to its two modular offshore rigs, it is operating on 33 offshore platforms and owns and operates 77 land rigs.