Archer begins P&A work on Statoil’s Heimdal field using MDR

Archer has begun plugging and abandonment (P&A) work on Statoil’s Heimdal gas field. The oilfield service company is using its Topaz modular drilling rig (MDR), instead of jack-up units, in order to keep costs down.

Topaz MDR (courtesy of Archer)

The Heimdal field is located in the Norwegian sector of the North Sea in a water depth of 120 meters.The field was developed via the HMP1 fixed platform which has an integrated drilling, production and accommodation facility with a steel base.
Production at Heimdal began in 1985. The site was shutdown in 2011, with the platform being used as a processing centre for other fields. Gas is transported to the platform from the Huldra, Skirne and Vale fields, and installation upgrades are underway to keep the field operational as agas processing and distribution hub until 2030.
The P&A contract, awarded to Archer by Statoil in February 2013, included the start-up, operating and decommissioning phase. Its estimated value is $115 million.

Cost advantages of using a modular rig
Archer’s Topaz MDR has been installed on the HMP1 platform and will used to permanently P&A the 12 wells. The P&A work of all of these wells is expected to take approximately 18 months. The main advantage of using MDR units for P&A work is at the cost side, providing a per-day cost saving when compared to the use of other types of structures.
“The advantages are that we can offer an alternative to costly, CAPEX demanding platform derrick reactivation projects or the use of more expensive units. In many cases an alternative could be to bring in a jack-up unit to do the P&A and this would typically be at a much higher day rate, so using a modular rig is a good business alternative,” said Geir Hagen, Project and Technical Manager at Archer.
“Our modular drilling rigs can do most of the required well operations you do from a typical North Sea platform derrick, so the MDR’s are good financial and operational alternatives to reactivating obsolete derricks or bringing in costly jack-ups,” Hagen added.

Well types and efficiency
With regards to efficiency in the plugging and abandonment of wells, the MDR’s provide more or less the same efficiency as typical platform derricks.
“Time wise it’s not a major difference because the MDR’s have more or less the same capacity as most of the typical derrick sets that you will find on fixed platforms in the North Sea. MDR’s will be more or less the same when it comes to time, but will be much more cost-efficient,” said Hagen.
“The duration of P&A depends more on the complexity of the wells. On Heimdal it’s fairly short and fairly simple wells, when I say simple it’s in the terms that they are not deviated and they are more or less vertical wells down to approximately 2,500 meters,” Hagen added.
Generally, P&A work on a North Sea well will take between one and two months, depending on the size of the well and its complexity.
“The P&A operation itself is fairly straightforward on Heimdal and you can typically estimate that it will take 30-35 days to undertake P&A work on a single well. When it comes to more complex ones, and we are taking about highly deviated wells at around 5,000 meters in length, depending on how many zones that have to be isolated, it may take double the time.”

Finding P&A opportunities
One of the challenges for contracting companies is positioning themselves for P&A projects, as these projects tend to be postponed. Operators seek to avoid having to undertake abandonment activities for as long as possible.
“The challenge for contractors is knowing when the P&A projects are going to be realised. Operators tend to push them to the right in order to avoid the costs for as long as possible, which is understandable. However, this tendency makes it more difficult for the contractors to position themselves to offer the best solutions for these projects. This is then influencing the technology development in this area.” Hagen said.
“On Heimdal, Statoil decided that the well integrity was at a level to begin P&A now, on others we see that they have been to the market, evaluated the cost and technology and went back to evaluations again,” Hagen added.

Technological collaboration
Further technological developments are required in order to provide more cost efficient strategies for P&A. Up till now, it’s been very much up to the contractors to position themselves to be able to offer the right technology and the right solutions to the operator.
According to Hagen, in addition to Archer’s MDRs, there is a good potential for further development of down-hole tools and technology that can help reduce the scope of work that is currently required.
However, the development of these technologies is slow as the required collaboration between operators and contractors is limited.
“Co-operation is definitely required between operators and contractors. As contractors we need to understand what the operators need and they need to be part of developing the solutions,” said Hagen.