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Case Study: restoring integrity to an unconventional cement packer design

20 February 2020

CannSeal deployed IntegritySeal technology on a client well in the North Sea to overcome gas influx issues and enable the development of an additional reservoir. Multiple IntegritySeal plugs were successfully installed to achieve the primary objective of reducing the gas leak to within acceptable limits and returning the well to production.

The Challenge

A client approached CannSeal to overcome gas influx issues in a North Sea well and unlock additional accumulations surrounding the wellbore. During operations to unlock these additional accumulations, the A- and B-annuli in the well developed gas influx issues which could not be addressed by conventional methods of sealing.

The risk of sealant filling the reservoir through the perforated sections was high and the cement below the estimated A-annulus Top of Cement (TOC) was of unknown quality.

Perforating through this thick cement sheet, while not damaging the outer casing on the low side, was vital to the success of the project which aimed to remove or reduce the gas leak to within acceptable limits.

The Solution

The CannSeal IntegritySeal was run on wireline to perforate and inject epoxy in the cement above the top perforation interval. CannSeal’s high viscous sealant forms a doughnut around the tubing in an open void, or fills large channels in a poor cement matrix. This process creates a plug independent of annular condition.

Cannseal’s delivery tool is fitted with a g-sensor, which shows the tools relative orientation. As a result, eccentric centralizers were used to point the perforation gun in the desired direction. This allows selective penetration with max reach topside to occur, while not damaging the second casing in the eccentric annulus.

The Result

A total of three epoxy injections were completed (31,6L ea.) throughout the job. The injections were placed in close proximity, and the CannSeal heater tool was deployed to increase the strength of the plug material. This enabled it to withstand high delta pressure in an anticipated large open void in the event there was no cement. Orientation of the tool was successful despite a low clearance, making the concept viable for larger casings in the future.

The aim of lowering the gas leak rate was successfully achieved. A month after the treatment was completed the situation was reported to be similar, with the pressure build reduced to a minimum. This successful operation facilitated the development of an additional reservoir for the client.

CannSeal’s Chief Executive Officer, Thomas Ringe, commented:

“We are very proud to be a problem solver for operators who experience unexpected well integrity issues. Without a successful barrier repair it would not have been possible to develop this additional reservoir through conventional methods.

Committed to innovation and global growth, we are proud to share success stories like this.”

The launch of CannSeal’s new mobile mixer was a strategic investment for the company. Facilitating the company’s proprietary epoxy resin to be mixed on-site, the mobile mixer opens up new markets independent of location as it removes constrictions associated with storage and curing.

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