Why you should be using time-activated sealants rather than pressure-activated sealants.

Sealant repairs during wellhead isolation tasks are classed as ‘temporary’, however this term can mean different things to different operators. With regular testing, a sealant isolation can last at least 25 years or the end of well life if left undisturbed.

A ‘permanent’ seal repair would involve replacing the seals or components with the original equipment manufacturer’s parts, which is uneconomical in most cases. We think that time-activated sealants are the better option for these so-called ‘temporary’ repairs.

But why?

Pressure-activated sealants:

  • Could ultimately cause more damage to the wellhead when applied to larger leaks or fragile equipment as they require high pressure to activate

  • Leave the voids filled with thin fluids where they can expand due to thermal effects, creating a scenario where an overpressure could displace the isolation and cause further damage to equipment and increase the leak

  • Create a small, local scab which can easily break, become washed out or can unintentionally be popped out under differential pressure

 

Time-activated sealants

  • Create a solid, flexible seal that can be deployed in environments up to 5k psi, allowing for pre-energisation while the sealant is curing

  • Can be available in several viscosities making them appropriate for use in various situations, regardless of the leak rate and path

  • Allows for the permanent plugging of control lines, chemical injection lines and capillary strings with a robust seal, restoring equipment integrity

  • Can isolate and seal larger leak paths with lower pressure options, making them a much more versatile solution. These sealants can be layered over each other to plug larger leaks as they will bond together to create a single piece isolation

Overall, using time-activated sealants to fill wellhead voids is preferable as it allows for a fix to be made with less operational downtime, extending the safe operation of the well until a repair or well abandonment can be carried out. It can also be used across a wide variety of instances and situations, as opposed to pressure-activated sealants.

High viscosity, time-activated sealants can be applied to gasket seal faces, sealing, and filling any corroded areas or scores.

 

When testing a time-activated sealant such as MS-Sealant or Mac-Seal, it is recommended to undertake leak-off testing in the direction of flow. This allows for well isolations to maintain integrity without the seals being pushed and flexed in the opposite direction which may lead to failures.

 

If you want to find out more information about our time-activated sealant products, MS-Sealant and Mac-Seal, read more: Wellhead Seal Isolations — Solutions — KCI Ltd or contact info@kciltd.co.uk

Georgina Hay