Offshore Annulus Gate Valve Isolation with Mac-Pac

The Client

We worked closely with a major oil and gas operator for a project in the North Sea, 130 miles offshore Aberdeen, to provide an isolation to a leaking inner annulus gate valve.

The project involved installing a VR plug in the wellhead to replace both annulus valves.

The Results

We successfully conducted an onshore trial to ensure we were able to repair the equipment as efficiently as possible once we got offshore before conducting the offshore operation. The test involved using a similar wellhead and valve arrangement, with Mac-Pac used to fill and test the valve whilst onshore.

This was all executed safely, efficiently and to the highest of standards.

This value adding, rigless isolation operation saved the well owner from potentially time consuming and costly freeze operation or barrier dispensation process. The project took around six hours to complete, compared to 2-3 days for a freezing job that would be the alternative option for the client.

“KCI have always provided personable, professional, and value-adding service in both surface and subsea wellhead issues. They don’t just provide a product; they complete the required engineering on each job to ensure the highest chance of success. KCI are interested in helping you where they can, but will also tell you what their limitations are when planning a job. If you have a leak, then we would recommend giving them a call!”

- Major North Sea Operator

The Challenge

The oil and gas operator recognized that a 15k, 2 1/16” inner annulus gate valve was leaking, and therefore a VR plug installation was required to replace both annulus valves.

Both annulus valves were failing so the outer flange could not be safely removed.

The Solution

Our unique product, Mac-Pac is as a sealant, so is ideal for a project of this nature. The product has a lifespan of at least 25 years and, due to its high viscosity, will stay within the valve cavity for a much longer time, compared to the commonly used tree grease as it does not get sucked out of the valve when opening under differential pressure for production valves.

For this project, we connected our unique deployment tooling to the Model ‘D’ Fitting on the inner annulus valve, then injected Mac-Pac through the fitting to displace the Clare 601 Grease that was currently in the valve. 

With the cavity now full of Mac-Pac, our team then functioned the inner annulus valve to the closed position to perform a PBU. The result was zero pressure build up detected. 

Following this, we removed the outer annulus valve and fitted a telescopic VR plug installation lubricator. The inner annulus valve was then reopened, and the VR plug was installed. This then went through thorough testing to ensure there wasn’t any pressure build up.

The inner annulus valve was then replaced, and the VR plug removed. They then fitted the outer annulus valve.

The equipment was then tested again to ensure that it was all functioning well. Once this was found to be the case, the team were confident that the well could return to production.