Control Line Isolations on a North Sea Wellhead
The Challenge
We were approached by a major UK oil and gas operator to provide isolations on three severed control lines on a well which operates downhole injection valves.
The three control lines had been severed at 6,800 ft due to high pressure water injection flow.
With a reservoir pressure of 3,000psi, “C-77” double block and bleed valves were fitted to the wellhead and control lines.
We needed to create a second isolation and clear sealant from the “C-77” block valves, so that the operator could carry out essential monitoring and wellhead maintenance.
Our Solution
We flushed the control lines with Transaqua HT2 to remove any obstructions to ensure injectivity and to determine if the lines held any pressure.
We then deployed our innovative Mac-Seal solution in each control line creating a 140ft plug to isolate the line.
We then injected a high viscous, fully synthetic grease behind the Mac-Seal to displace the sealant past all working parts of the “C-77” block valves and tubing bonnet stabs.
We completed this activity within two hours, leaving the Mac-Seal and synthetic grease to cure overnight.
The lines were then pressure and leak-off tested for both high and low pressure. All lines were vented, and no pressure build up was witnessed.
The Results
Our robust deployment of the solution and pressure testing activity, resulted in successful isolations and ensuring all three control lines had no leaks.
This value-enhancing, rigless isolation solution saved the operator from a potentially time consuming and costly workover or long term suspension.
Leading to an extremely satisfied customer as they were able to bring the well back online safely and efficiently, without excessive downtime.
“KCI have always provided personable, professional and value adding services 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!”