Over 3000 wells onthe Norwegian continental shelf will be plugged in the decades ahead. Exedra AShas developed a method to verify that the wells are not leaking.

Source: innovasjonspark.no
Text: Hilde Garlid
- 30. august 2019

April 10, 2019, the company signed an agreement with ConocoPhillips andEquinor to develop a prototype. The company also receives support fromInnovation Norway's environmental technology program. Validé AS assists with business developmentand has previously invested in the company. Together with theindustry players, Validé is now also investing through the seed-fund ValidéInvest I.

"This means that we have solid, demandingcustomers in addition to professional investors as the company enters a phaseof approximately 2.5 years of technology development, piloting andtesting," says Bernt Pedersen, CEO of Exedra AS.

Customersparticipate in technology development

There is a light morning atmospherearound the coffee table in Innovation Park Stavanger. The founder, BerntPedersen, is slicing the cake. The two biggest and most attractive futurecustomers on the Norwegian continental shelf, has joined the development team.

- We are two years away before we can test our method in an actual wellon the Norwegian continental shelf, but now we have solid industrial partnersin the pilot development phase. Itis very valuable, says Bernt Pedersen, who for a couple of years has been atenant in Innovation Park Stavanger, and has developed his company from theco-working area NEST.

-ConocoPhillips and Equinor represent over 70per cent of the Norwegian well plugging market. The oil companies areresponsible for leaving the boreholes properly when the oil and gas fields areone day being closed permanently. The authorities demand that plugged andabandoned wells shall not leak to the external environment. Our method helps to verify whether it happens or not, says the physicistand engineer from NTNU, who has background from the development department atNorske Shell. He has been supportedby the  incubator Validé since 2016, andin January 2017 he established Exedra AS. Sincethen he has brought in several private investors, and now his biggestcustomers.

Liability with no time limit

- If you need to plug a well - do it right the first time, is the clearmessage from Ivar Blaauw, who is responsible for technology development indrilling and wells, with the main emphasis on Plug & Abandonment, inConocoPhillips.

The operator’s responsibility does not only apply to drilling. Theresponsibility for cleanup and well plugging at the end of a field’s life isactually unlimited.

The oil company Saga experienced the horror scenario of a well blowout31 years ago. 20,000 barrels of oil a day poured into the ground below theseabed for almost a year. It took thecompany 14 months to seal what was popularly called the "Ghost Well".The entire sealing operation was both demanding and very costly for thecompany.

Today, such wells are plugged with cement, but work is underway todevelop other, better-suited materials, such as for example resin.

-ConocoPhillips Norway has plugged around 100 wells so far. ‘’We mustmake sure these are sealed before we leave them, and we will follow them up aswell. We are not required to do so by law, but we are always responsible ifsomething happens after the field is closed.’’ Blaauw says.

From 1966 until today, more than 5500 wells have been drilled on theNorwegian continental shelf. Some of these are exploration wells that are oftenplugged immediately.  But developmentwells are plugged after production shutdown. Many new wells are also to bedrilled.  And at one time or another allof these will be plugged and left back to nature again.

‘’ConocoPhillips will plug close to 80 wells by2028, and we have about 300 wells in total. Equinor'sactivity is significantly greater. Thisis a job that will last for many decades to come.’’, says Ivar Blaauw, whoestimates that an average of 100 wells will be plugged in the year ahead.

Tests from the insideout

Therefore, the timing for Exedra's method and technology is very good. Theirmethod verifies and ensures that the wells are leak tight, with an accurate,cost-effective and simple method.

-Today pressure is applied from above, but it is not tested whether itleaks from the reservoir upwards. The authorities' requirement is that pluggedwells need to be leak tight towards the external environment.  That is, the sea, the seabed and theatmosphere needs to be protected against pollution and leaks. ‘’Our methodtests from the reservoir side of the plug, and upwards to the externalenvironment. It is also unambiguous, and more sensitive than today's methods.’’says Pedersen.

-So it's not the plug itself that seals the well you're developing?

-No, we provide a verification solution that provides a more accurateanswer to whether the well is leaking to the external environment. The verification methods today are not sensitive and cangive ambiguous results. Therefore, there may be leaks that are not detected, orvice versa; the wells may be tight but the verification may show leakage, saysPedersen.

The requirements from the authorities states that the wells should be leaktight for the eternity, but there is no permanent monitoring of the pluggedwells. Nobody knows how many of the permanently plugged wells are leaking, andwhat is leak tight today can in theory be leaking tomorrow.

‘’Some surveillance of plugged wells has been performed on land wells inNorth America and Canada. Between 10 and 35 percent of these plugged wells showsproblems with leakage.’’, says Pedersen.

‘’Our method is more reliable and provides aninsurance scheme for the oil company. If wells leak sometime in the future,operators can document that they have tested for leakage.’’, says Pedersen.

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