Alternative Barrier Materials

A range of new technologies are being developed which utilise the properties of a range of organic and inorganic materials as alternatives to Portland cement which has been traditionally employed in the construction P&A barriers. These alternative materials offer potential advantages over cement plugs in relation to a number of key barrier criteria including; impervious nature, deployment methodology (e.g. through tubing technology to support rigless P&A), control over placement and barrier formation, material stability and longevity; ability to interface with other barrier elements (e.g. formation, cement, casing/tubing). With well decommissioning activity in the UKCS ramping up, industry is focussed on qualification of these alternative barrier materials which creates a pressing need for access to wells for field trials.

Potential alternative barrier technologies

• Modified in situ materials
• Low melting point metal alloys
• Thermosetting Resins & Polymers
• Geopolymers
• Non-setting grouts
• Inorganic chemistry
• Advanced cements

The Challenge

North Sea Transition Authority has challenged industry to reduce the cost estimate of UKCS decommissioning by over 35% from the 2017 baseline estimate. Well decommissioning accounts for circa 45% of the total basin cost estimate, providing a significant opportunity to help deliver the necessary cost reduction. It is widely acknowledged that alternatives to traditional cement based P&A approaches could increase the application of rig-less well abandonment techniques with potential for considerable cost savings. There is, however, a time-limited window of opportunity for these technologies to have a meaningful impact on cost reduction which necessitates the requirement to accelerate the transition between product development and commercialisation. High cost and technical risk associated with trialling new technologies offshore is identified as an obstacle to generating performance data, hindering the pace of development and leaving many operators reluctant to consider pursuing alternatives to cement.

The Solution

Field trials can be performed in land wells for significantly lower cost than offshore in the North Sea and with simplified logistics. This results in an increase in the number and pace of trials that can be delivered for the same level of funding. Using a collaborative funding model, well operators can reduce the individual cost of participation while securing access to trial data for a wider range of potential technical solutions.

In Alberta, Canada, the onshore well abandonment liability runs to several hundred thousand land wells with an estimated forty thousand of those exhibiting well integrity leaks resulting in sustained casing vent flow. This has created a pressing need to develop rig-less approaches to casing leak remediation as part of well decommissioning which is technically suited to alternative barrier material solutions and aligned with UK industry needs to reduce well abandonment costs. This provides the ideal opportunity for a collaborative approach between UK and Canadian industry to support technology developers utilise a lower cost environment to generate the volume of field trial data required by operators to qualify the solutions for inclusion in well decommissioning programmes and secure acceptance by the regulators of alternative approaches to P&A.

The Industry Lead Sponsor

Spirit Energy was invited to lead this programme by the TLB in recognition of their demonstrated commitment to advance industry experience of Alternative P&A Barrier technology through collaboration. Spirit (as former entity Centrica) participated in an earlier JIP to support development of a Thermite based barrier solution, providing access to wells in Canada, management and well engineering for field trials. Spirit subsequently completed the first onshore and offshore alternative barrier solution field trials working with the developer Interwell. The company has taken a prominent role in the workgroup preparing an update to the OGUK guidelines on P&A barrier material qualification and were a founding member of the Net Zero Technology and Alternate Barrier Collaboration Forum.

Rocksolid® field trial in Alberta – intervention mast at wellsite Photo courtesy of Interwell