A 2.125 in. inflatable cement retainer engineered by Aberdeen-based Unity has achieved well isolation in Central Italy after conventional cement squeezes failed against a thief zone behind a slotted liner. The intervention, delivered for SMAPE on behalf of a major international oil company, closed out a well that had resisted both cement-only and off-the-shelf mechanical isolation approaches.

The operator initiated the project after repeated cement squeeze operations could not deliver the required isolation. A thief zone behind the slotted liner was absorbing the cement, starving the treatment of the volumes needed to build an effective barrier.

Why standard equipment could not do the job

Well geometry compounded the problem. Any mechanical isolation tool had to pass through a tight 2.188 in. nipple restriction and then expand and set reliably inside a 3.958 in. internal diameter above the thief zone. Standard retainers available from individual OEM catalogues could not satisfy both constraints in a single run.

A low fluid level in the well added further operational complexity. Unity's planning had to account for the risk of premature disconnection during the cement job and avoid pressurising the treatment packer beyond its rated limitations.

How Unity configured the solution

Unity's thru-tubing team built the custom 2.125 in. inflatable cement retainer by modifying the bottom-hole assembly with:

• A dual check valve system
• A shear disconnect
• A cement plug set on top of the retainer

The configuration allowed the rig team to release from the cement retainer immediately after squeezing, without dropping additional balls or encountering problems once the packer inflated.

Unity sources components across the OEM market and engineers them around the specific demands of each well rather than working within the limits of one supplier's product line. For this well, that OEM-agnostic approach produced a first-time configuration built on established principles.

Unity Thru-Tubing Operations Manager Chris Myles said: "This is the first time we have used this configuration, which draws on established principles. This is really the heart of how we work at Unity thru-tubing. We're not tied to one OEM's solution, so we can pull in whatever's most appropriate, adapt it, and build something that fits the exact problem in front of us. That's what sets Unity apart, and it's what clients get in return – a solution built around their well requirements, not the other way round."

A second collaboration with SMAPE

The award marks Unity's second project with SMAPE, an independent engineering company specialising in coiled tubing and well services. Myles said the repeat work reflects the value the service company sees in custom engineering for complex integrity jobs.

"This project marks our second collaboration with SMAPE, and it's fantastic that the team see the value we bring to complex well integrity challenges," Myles said. "These are often the kinds of jobs where a standard approach isn't enough, so being able to work closely with the client and develop a solution around the specific requirements of the well is where our expertise really makes a difference."

Where the work sits in Unity's intervention build-out

The Italy job forms part of Unity's broader investment in well intervention capability. Since the beginning of 2025, the company has significantly expanded its intervention tooling portfolio, strengthening its ability to supply integrated well integrity and intervention solutions through a single supplier relationship.

The pitch to operators is a streamlined supply chain. By combining in-house engineering, OEM-agnostic tool selection and operational experience, Unity aims to remove the cost and complexity of managing multiple suppliers on complex well integrity work while extending asset life.

Unity, part of the FrontRow Energy Technology Group, cites a 30-year track record supporting operators worldwide on risk reduction, constraint management and late-life asset operations.

What to watch next

Watch for further deployments of the dual check valve and shear disconnect configuration on wells with nipple restrictions below 2.25 in., where conventional retainers cannot run. The measure of the 2025 tooling investment will be whether these bespoke builds shorten the interval from failed squeeze to verified isolation on upcoming European well abandonment campaigns.