Industry first well integrity and completion solutions – the epoxy way

By Thomas Ringe, CannSeal

CannSeal’s technology is redefining industry approaches to zonal isolation, well integrity and completions
CannSeal’s technology is redefining industry approaches to zonal isolation, well integrity and completions (photo: CannSeal)

As a growing emphasis shifts towards extending the lifecycle of existing wells, well integrity issues will continue to be an ongoing issue. In 2018 the UK Oil and Gas Authority found that 62% of well shut-ins in UK waters resulted from well integrity and water production issues.

Every well is unique, with complex and diverse structures and conditions at play. These conditions can be natural or occur as part of the drilling process. At CannSeal, we are reimagining traditional approaches to well integrity and zonal isolation by providing tailored epoxy solutions that are as individual as the well itself. Using our epoxy sealing solution, and market leading delivery tool, we can accurately plug the annulus in both vertical and horizontal wells. This process allows us to extend the lifecycle of the well or to re-establish well integrity, depending on the issue at play.

With a track record of over 76 runs, major operators have adopted CannSeal’s epoxy technology to overcome a range of challenges at all stages of the well lifecycle, from initial completions to retrofits and P&A. This includes the utilisation of industry first applications that meet the goals of our customers and wider industry demand for effective and innovative alternatives to traditional solutions.

Developing a unique epoxy solution for each project
Our tested and qualified epoxy sealant is at the core of our approach. Developed by our team of scientists in Stavanger, the epoxy is tested under expected well conditions before any project takes place. This means that the epoxy reaches the well site having been specially developed to fit the job in hand.

Both horizontal and vertical on-site test wells ensure that each solution can be examined under the correct temperature and pressure. Our vertical test well has a depth of 40 metres, and our horizontal test cell can extend even further beyond that. With temperature testing of up to 150-200° C and pressures of up to 300 bar, some of the harsh conditions of petroleum wells can be simulated beforehand in the workshop. As a result, each epoxy mixture boasts varying viscosity, rheology and density, and is tailored to the unique characteristics of the well. This is unlike other solutions, such as coiled tubing operations or cementing, which require intensive on the spot operations. These traditional approaches also offer a lesser degree of control over the resulting behaviour of downhole devices and injections.

Comprehensive testing is the cornerstone of epoxy development
Comprehensive testing is the cornerstone of epoxy development (photo: CannSeal)

Our epoxy solution can solve two distinct challenges for operators – zonal isolation and well integrity issues.

  • Zonal isolation: ZonalSeal targets zonal isolation challenges. With plugs of bespoke epoxy injected into open and gravel packed annuli using the CannSeal tool, it can be used on wells with or without screen completion. The need for coiled tubing is removed completely and, as such, there is no need for a full well workover with platform derricks or a rig workstation. This means zonal isolation can be achieved with minimised costs, time and risks – ensuring further completions and production goals can be achieved.
  • Well integrity issues: IntegritySeal is our solution to enable effective well integrity management and can be retrofitted to any well to mitigate sustained casing pressure or provide a remedial integrity barrier to prevent lost circulation, and plug leaks, cracks and fissures. It can also be adapted for plug and abandonment (P&A) operations.

Both solutions are developed and premixed before being sent to customer sites, ensuring they arrive ready to be deployed. Installed using the specialised CannSeal delivery tool under the supervision of a skilled CannSeal engineer.

CannSeal Wireline downhole tool
CannSeal Wireline downhole tool (illustration: CannSeal)

Case Study: Overcoming complex well challenges – reducing gas production in a gravel packed annulus
On a recent project for a major operator in the North Sea, the operator was experiencing gas production from a lower reservoir section with a high delta pressure during ongoing well completions. The gas production required a restriction through zonal isolation, while still enabling planned gravel pack installations on the entire top-hole section. Conventional sealing methods could not support successful annular restrictions simultaneously to further completions, so alternative solutions were required.

We worked closely with the operator to develop an innovative solution using our epoxy, the delivery downhole tool, and a 6-metre-long downhole pipe. The blank pipe was installed first between the screen sections to create a restriction between the two reservoir zones, followed by the gravel pack completion. Following this, the CannSeal tool was run downhole to find the blank pipe, perforate the liner, and inject the bespoke epoxy solution.

This bespoke 3 million cP epoxy sealant was highly viscous and particle free, enabling it to penetrate and fill micro-gaps while remaining self-carrying in open voids. In this application, approximately 13 litres of epoxy was injected at a maximum injection pressure of 132 bar to create a 1.6m long plug in the annulus.

The plug was successfully placed in the gravel packed annulus between the 5.5-inch blank pipe and 8.5-inch open hole. This enabled zonal isolation and further installation of an Interwell Choke that together reduced gas production from the lower zones. The operation was an industry first, using an electric wireline tool to place an epoxy plug in a gravel packed annulus. The solution overcame complex well conditions and laid the foundations for further unique epoxy applications on projects at all stages of the well lifecycle.

The future of integrity and completions
With a strong track record of success on highly complex wells, our solution is demonstrating its ability to re-establish well barriers in the harshest and hardest to reach zones of oil and gas wells. The benefit to operators of a bespoke product that is injected with pin-point precision is clear. Put simply, it facilitates successful, efficient, and cost-effective operations that can overcome challenges where off-the-shelf solutions have failed before.

We are proud that our epoxy is being utilised in this manner. With new projects on the horizon as we expand into new markets in the Middle East, this is the beginning of an exciting and productive period for the company. Our status as an Interwell company since late 2020 also means that we can provide the industry with the latest, state-of-the-art combination of technologies and scaled up global capabilities. As such, our proven unique solutions for unique wells are available to meet the growing industry demand for effective completions and integrity support as we streamline operations for future-proof sustainable operations.

Oil and Gas Authority, Wells Insights Report 2018

Thomas Ringe, Managing Director, CannSealThomas Ringe, Managing Director, CannSeal