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Why Bismuth?

Conventional cement plugging operations are subject to a number of disadvantages, including, but not limited to:

  • Expensive; upwards of £1.8M/well
  • Time consuming; >2 days
  • Cement shrinks over time; about 1.5 – 3% in volume leading to a reduction in seal integrity
  • Failure; Cement often fails, leading to costly re-plugging jobs
  • Plug size; Re-entry to the well is difficult due to the length of the cement plug (up to 500')

Bismuth Key Facts

Bismuth has the unusual property of expanding upon freezing, similar to water becoming ice.

It can be combined with various other metals to produce a wide range of fusible (low melting temperature) alloys.

Once molten, these alloys have a very low viscosity, allowing them to conform to the profile of any surface they come into contact with.

When expanding bismuth comes into contact with the casing ID, a large contact load is generated; this leads to an ultra high integrity metal-to-metal seal being formed.

The bismuth casting process is a matter of hours, as opposed to days, as it is for cement setting.

A 3' (0.91m) bismuth plug can readily outperform a conventional cement seal, which may be up to 500' (152m) in length.