Page 30: of Offshore Engineer Magazine (Jan/Feb 2021)

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FEATURE PLUGGING & ABANDONMENT

Source: BiSN

Late last year, the company performed system integration trials of its technology, placing and melting a bismuth alloy using a cable deployed downhole electrical heating technol- ogy from Aarbakke. This was in 9 5/8 inch within 13/3/8 inch casing, with a cement-?lled annulus. To show milling operations could be avoided, Wellstrøm, together with Core

Laboratories, achieved a controlled shattering of the cement annulus ready for the application of molten bismuth. It was pressure tested during placement and is now back at Well-

Strøm headquarters for testing to ISO14319. WellStrøm says the sealing concept is based on a 3,000-year-life seal design already quali?ed by Bureau Veritas to DNV-RP-203,

ISO 14310 (VO).

The trials follow a two-year program to deliver 7-inch alloy plugs for deployment in the North Sea, rated to 6,000 psi dif- ferential pressure at 60 cm (2inch) in length. This included developing the formulation of the metal seals, supported by

Innovate UK. To establish mechanical properties and creep behavior under service pressure and temperature conditions,

Rawwater worked with the University of Aberdeen, through an Oil & Gas Innovation Centre (OGIC)-funded partner- ship. The result is a suite of alloys for onshore, offshore and subsea P&A in downhole conditions from 70 – 90°C and 140 – 160°C.

Rawwater managing director Professor Robert Eden says

Source: Rawwater 30 OFFSHORE ENGINEER OEDIGITAL.COM