by Jan Hester

• With ongoing production from Ekofisk and Eldfisk, other redeveloped fields and new exploration projects in the works, the future looks bright for ConocoPhillips Norway.
• The Greater Ekofisk Area currently produces 180,000 barrels of oil equivalent gross per day between Ekofisk and Eldfisk and estimates that about 2 billion barrels of movable oil are left in the reservoir.
• About half of ConocoPhillips Norway’s production comes from partner-operated assets.
• The company produces oil and gas in a safe, environmentally sound way while seeking additional ways to continue to reduce emissions.

When Phillips Petroleum discovered Ekofisk in 1969, the company estimated it would recover less than 20% of available resources from the giant North Sea field. Fifty years later, things look very different.

Technology has dramatically improved the way companies produce oil, breathing new life into fields once thought to be nearing depletion. With ongoing production from Ekofisk and Eldfisk, other redeveloped fields, and new exploration projects in the works, the future looks bright for ConocoPhillips Norway.

Greater Ekofisk Area

ConocoPhillips’ Greater Ekofisk Area is located in the North Sea, 300 kilometers southwest of Stavanger. In addition to Ekofisk, the area consists of producing fields Eldfisk and the remotely operated Embla.

The business unit currently produces 180,000 barrels of oil equivalent gross per day between Ekofisk and Eldfisk. With about 2 billion barrels of movable oil — oil that can release from the pores in the reservoir rock — left in the two fields, production could continue for 30 to 40 years. Much will depend on whether the recovery factor will continue to improve through technology and innovation.

While the Ekofisk field is 50 years old, ConocoPhillips has redeveloped and recapitalized much of the infrastructure and has plans to streamline future development. The company plans to add wells and pipelines that tie into existing facilities, as well as use remotely operated facilities, including subsea wells and unmanned platforms.

The company also plans to continue drilling wells from the newer existing platforms.

Ekofisk Operations Manager Kurt Fredheim notes that it’s challenging to fight natural decline.

“The Ekofisk field still produces 125,000 to 130,000 barrels of oil equivalent gross per day, but a lot of effort goes into maintaining that production. We’re introducing new technologies, including more-efficient drilling as well as advanced seismic imaging and field modeling,” Fredheim said. In addition, the Ekofisk Field Complex serves as a hub for third-party volumes, a valuable exploitation of the infrastructure in the area. Oil is transported to Teesside in the U.K. via Norpipe, and gas is transported to Emden, Germany through the Gassco pipeline system.

Rune Tufta is manager of Eldfisk Operations. “Over the past 40 years, the Eldfisk and Embla fields have produced more than 1 billion barrels of oil equivalent. It’s a huge reservoir, with original resources in place estimated at 2.7 billion barrels of oil equivalent. We continue to develop the fields and are preparing for a lifetime to 2050.”

Commitment to sustainability

As part of its commitment to sustainability, the company is increasing the use of its waste heat recovery unit (WHRU) and recently installed a new electrical power cable to Eldfisk Bravo. The WHRU uses waste heat from exhaust stacks to create steam that is converted to electricity for use in the field.

“Utilizing that energy enables us to cut CO ₂ emissions, as well as reduce emissions by removing diesel generators,” Tufta said.

Reviving Tor

The Tor field in the Greater Ekofisk Area went online in 1978, but production was suspended in 2015 when the production platform’s lifetime expired. ConocoPhillips and its partners recently submitted a redevelopment plan to the Norwegian Ministry of Petroleum and Energy for the Tor II project, one of several opportunities in the Greater Ekofisk Area that enable continued efficient operations toward 2050.

“Tor II entails drilling seven production wells in the Tor formation, along with a planned pilot well to test long-term productivity in the Ekofisk formation, ” said Jan-Arne Johansen, general manager, Norway Operations.

Resource potential for the Tor II project is in the range of 60 to 70 million barrels of oil equivalent. New subsea facilities will be located approximately one kilometer west of the original Tor platform, with no connection to the shut-in facilities. The eight subsea wells will be connected by pipeline to existing risers at the Ekofisk Complex.

“Having produced the Tor field for 37 years, we are proud to continue to extend development, enabling a total production lifetime beyond 60 years,” said Johansen.

Working with partners

About half of ConocoPhillips Norway’s production comes from partner-operated assets, including the producing fields Heidrun, Visund, Oseberg, Grane, Troll, Alvheim and Aasta Hansteen.

“ConocoPhillips is an active participant committed to ensuring the best value for the company, and we often challenge the operator when decisions are being made,” said Dag Sanner, general manager, Norway Partner Operated, Commercial, External Affairs & Libya.

The Heidrun field, located off the coast of mid-Norway, was discovered in 1985 by Conoco. After being developed, operatorship was transferred to Statoil, now Equinor. The field is likely to produce for 30 more years.

ConocoPhillips also holds a small equity interest in the giant Troll field that amounts to 12,000 net barrels of oil equivalent per day. A new part of that field is being developed, and ConocoPhillips’ small equity interest will add another 35 million barrels of oil equivalent at a very low cost of supply.

“We have good production from the Alvheim field and the recently developed Aasta Hansteen field, which is in 3,000 feet of water,” Sanner said. Aasta Hansteen, the newest development, started production in late 2018.

Maintaining asset integrity

In the harsh North Sea environment, maintaining asset integrity is an ongoing challenge.

“Internal challenges include corrosive products in the oil stream. From the outside, we have corrosion from saltwater, the marine environment and condensation,” said Robert Skrede, manager, Engineering & Asset Integrity. “A major concern is corrosion. We rely on our detection systems as well as people always being on alert. Over time we’ve also seen that water flood changes the composition of the well stream, so we need to factor that into making the right decisions.”

To manage issues inside the pipe, the business unit relies on corrosion inhibitors and ongoing inspections.

“Pipelines are coated on the outside to protect them from sea water. Inside the pipelines, we run intelligent pigs (devices used to inspect pipelines) to look for corrosion development. We work closely with scientists in the company’s Bartlesville labs, who support us by testing and sourcing chemicals to address issues such as scale prevention and hydrogen sulfide removal. We couldn’t do what we do without their help,” Skrede said.

Maintaining asset integrity also involves an ongoing effort to keep facilities safe from the sea and storms. To address subsidence of the seabed, in 1987 the company raised all Ekofisk Complex steel platforms by six meters, and new facilities are constructed at adequate height.

“Subsidence makes everything closer to the waves, so we make sure we have sufficient strength in the jackets. It’s up to us to make sure the facilities are up to the challenge and can withstand a 10,000-year storm,” Skrede said. “We also have plans in place to protect people from potential hazards. We’ve never had to do it, but if we ever face a storm of that magnitude, we have the capabilities to evacuate the entire field.”

Walking to work by boat

Tor Inge Hansen, manager, Projects Europe & North Africa and his team are responsible for the facilities portion of ConocoPhillips Norway’s projects. “After the 2014 downturn, we had to find new, smaller facilities concepts for new developments. To manage costs, we worked with the industry to standardize subsea production facilities and implemented unmanned wellhead platforms, where workers could ‘walk to work by boat.’”

Hansen and his team have played a key role in removing obsolete platforms at Ekofisk. To date the team has removed 140,000 tonnes of material, with 98% percent recycled. “We work with demolition companies that handle the materials in accordance with Norway’s stringent regulatory requirements,” Hansen said.

Solving difficult challenges

“Climate change is a hot topic in Norwegian society right now,” said Johansen. “We are proud to produce oil and gas in a safe, environmentally sound way. At same time there’s a need to continue to reduce emissions through innovation and technology. We’re keen to take an active role. We’ve solved difficult challenges before, and we can do this one.

“Norway is fairly young in terms of exploration, and the knowledge we have built over 50 years provides us a great foundation for the future. We have a great reputation we want to maintain,” Johansen said. “We have a very competent and experienced organization, and we would like to have more fields to leverage that experience for the company.”

Exploration

To replace declining reserves at Ekofisk, ConocoPhillips Norway is looking for oil and gas that can be developed with a low cost of supply. Exploration focused outside Ekofisk is critical for the business unit, and there is great potential on the Norwegian continental shelf.

Over the last three years, the business unit has built an interesting portfolio of exploration licenses, including eight operatorships. In 2019, the first of three planned wells were drilled in the North Sea close to Grane, Heimdal and Alvheim, where there is already production infrastructure in place.

“It’s exciting to implement the new strategy with the drill bit after three years of portfolio building,” said Exploration Manager Arild Skjervoey.

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_{Cautionary Note to U.S. Investors – The SEC permits oil and gas companies, in their filings with the SEC, to disclose only proved, probable and possible reserves. We use the term “resource” in this article that the SEC’s guidelines prohibit us from including in filings with the SEC. U.S. investors are urged to consider closely the oil and gas disclosures in our Form 10-K and other reports and filings with the SEC. Copies are available from the SEC and from the ConocoPhillips website.}