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year, with 103 tools run, compared with brings together Norwegian company 50 in 2019 and 17 in 2018, as the com- Aarbakke Innovation’s downhole elec- pany’s technology has been adopted and trical heater technology and well in- not just for P&A. Recent projects in- tervention techniques, consultancy K2 clude a seal through two strings (9 5/13 Oil?eld Services’ perforating and P&A inch out to 13 3/8 inch then 20 inch) expertise, and UK-based Rawwater offshore California, which had been sec- Engineering Company’s bismuth alloy tion milled, in case of lack of integrity in knowledge (OE: October 2019). the cement behind the casing. On a new well, in Denver, the bismuth alloy solu- tion was used to create a gas-tight an- nulus to prevent annular gas migration.

The bismuth alloy could be deployed over just 6ft in a “surgical way” exactly where the issue is instead of needing 100ft of cement, says Carragher. This includes deployment via e-line, slick line, coil or drill pipe, he adds. Com- ing up is a campaign from a light well intervention vessel offshore Angola for

BP, part of a follow-on campaign BiSN was involved in previously. This will see the tools run subsea using ROVs.

While section milling is still done,

BiSN is looking at an alternative based on using liquidized thermite. BiSN normally uses thermite as a heating el- ement. But the liquidized version will be pumped through perforations and ignited to effectively melt out casing sections, including control lines, etc., ready for BiSN’s regular plugging tools to be run or just to aid pulling the cas- ing. This will be able to be done through 56ft long, says CEO Paul Carragher. multiple casings, says Carragher. In fact,

It was the ?rst in a 40 plus tool cam- the company recently tested the tool on paign providing gas tight environmen- tal barriers on Valhall wells – where a mock-up to melt through 2 7/8 inch compaction and seabed subsidence are then 7 inch and then through a 9 5/8- known issues. Tool sizes to be run on the inch casing, with just 25 kg of thermite, project include 13-3/8 inch out to a 20 says Carragher.

annulus, 18 5/8 inch out to 24 inch, and

An electrically heated 20 inch out to 30 inch on wells, which

WellStrøm are section milled before the tool is run.

Also working with bismuth alloy is

The company, in which BP is a co- investor through BP Ventures, says it Norwegian consortium WellStrøm. Un- has now deployed its bismuth solution like others, WellStrøm is using an elec- more than 180 times with no emittance trical heater to melt its bismuth down- of gases once placed. 2020 was a big hole. Formed last year, the consortium january/february 2021 OFFSHORE ENGINEER 29