Squeezing Out The Last Drops

The Norwegian Continental Shelf has become a mature oil province. Oil production is considerably lower than its peak year in 2001. The industry has been unable to offset production decline from existing fields with new discoveries. The average recovery rate on the NCS of 46% is more than its international peers, but still not enough to stem dwindling output.

Production Forecast for the Norwegian Continental Shelf.  © Norwegian Petroleum Directorate/Ministry of Petroleum and Energy

Government-Appointed Committee
Against that backdrop, the Norwegian Petroleum and Energy Ministry commissioned a committee led by Knut Åm, former Phillips Petroleum senior vice president and head of exploration and production worldwide, to outline ways to boost oil recovery from Norway’s ageing fields.

The impetus was the obvious potential for additional value creation. The report said that by raising the current recovery rate on the ten largest fields from the current NCS average of 46% to 70%, the result could be the equivalent of two new Ekofisk fields in terms of reserves, i.e. an additional 6.3 billion barrels.

That would represent a sizeable chunk of the report’s vision to raise 16 billion barrels of improved oil recovery in new and existing fields. If the industry reaches the 16 billion barrel goal, it could create an additional USD 1.2 trillion in petroleum revenues for Norway.

“We think it is possible under the right conditions to get the average (on the NCS) up to 60%,” said Åm. “Under the wrong conditions, we might lose the reserves.”

The committee specifically proposed 44 measures within five areas it deems critical for reaching this goal: regulatory framework, costs and profitability, competitiveness, technology development and implementation, and other specific technology areas.

Among one of the measures is a call for revising the voting rights among license partners to enable those with a majority to make the final decision. Another measure pushes for introducing simpler well designs that could make use of smaller, cheaper rigs. In the short run, though, the most important of these will be to increase drilling, said Åm. In the long run, it is technology and chemical injection.

The recommendations from the report will be considered by the petroleum and energy ministry and parts potentially included in a White Paper to parliament next spring on petroleum policy.

The Heidrun field is being considered for the use of BrightWater technology, which entails adding nano particles water injected into oil fields to boost recovery. © Kjetil Alsvik/Statoil

Petoro’s Focus on Mature Fields
One of the big companies leading the drive to improve oil recovery rates on the NCS is Petoro, the state-owned corporation responsible for the management of Norwegian State’s Direct Financial Interest (SDFI) in petroleum operations. Its portfolio comprises 137 licenses and 40 fields in production, representing more than a third of Norway’s petroleum reserves and a quarter of the country’s total oil and gas production.

As part of its new strategy plan 2025 launched this year, the company has identified three priorities: increasing oil recovery in its mature fields, the gas value chain, and opportunities in the Vøring area of the Norwegian Sea and the Barents Sea.

The most important part of this strategy plan will be to maximize recovery from the big maturing fields in its portfolio. The ten largest field developments in its portfolio accounted for 80% of its oil and gas production in 2010. The seven big mature fields in its portfolio, which have been prioritized by Petoro recently, are Oseberg, Snorre, Gullfaks, Troll, Heidrun, Åsgard, and Ormen Lange, according to Sveinung Sletten, Petoro spokesman.

Petoro has recommended several measures as part of its general strategy to improve oil recovery. These include, the industry equipping itself through technology and collaboration to drill two to three times as many production wells, supplementing water and gas injection with new methods, better data gathering for understanding the reservoir, and strengthening research and development.

“The key to getting the most out of the fields is to drill more wells,” said Sletten. “We are concerned that the number of producing wells on our fields on the NCS is lagging behind.”

The Heidrun field is a good example of how Petoro is trying to maximize recovery. The company has a project together with Schlumberger to map the potential for increased recovery at this field, which currently has a recovery rate of 47%. Petoro is particularly interested in looking at ways of bringing down drilling costs, which have doubled over the past four years. A critical aspect of this is to improve the understanding of the reservoir and how liquids move over time.

BrightWater
Petoro is also looking at the possibility of using BrightWater, a technology co-developed by Nalco, BP and Chevron that uses nano particles to make water injection more effective. Chemicals in the form of tiny particles are injected into the wells and expand when they meet the heat of the reservoir, blocking water from taking the easiest route through the reservoir and forcing it into parts of the formation where oil remains.

Petoro said the technology has been used in other parts of the world with fairly good results. If approved for use on Heidrun, it would mark the first time the technique is used in Norway. The company expects it could be used on a pilot well as early as next year.

“If successful, we could look at other wells on Heidrun and other fields,” said Sletten. “It would perhaps have the same potential as drilling one well and if so, it would be for a very much lower price.”