Removing a Christmas tree from a live CO2 injection well is not a routine job. The moment that pressure-control equipment comes off, a verified barrier between workers and the gas below becomes the only thing standing between a controlled operation and a serious incident.
In Western Australia, a major operator faced exactly that situation — and the solution Halliburton brought to the well site had never been deployed anywhere in the world before.
A high-stakes operation with no room for error
Well intervention on a CO2 injection well is a fundamentally different proposition from routine maintenance work. When an operator needs to remove and reinstall a Christmas tree — the assembly of valves and fittings that sits atop a wellhead — the well is momentarily left without its primary pressure-control equipment. In that window, the only thing protecting the work crew from the pressurized gas column below is a verified downhole barrier. Without confidence in that barrier, the operation can’t safely proceed.
For the operator in Western Australia, the stakes were straightforward. Personnel working in the well bay area would be directly exposed to risk if the barrier failed or couldn’t be reliably confirmed. The requirement wasn’t simply for a barrier — it was for one that could be verified continuously, in real time, throughout the intervention.
Traditional barrier monitoring methods couldn’t meet that standard. Conventional approaches typically rely on periodic manual pressure checks rather than continuous surveillance, leaving gaps in the data picture at precisely the moments when unbroken assurance matters most. On a CO2 injection well with personnel on site, that level of uncertainty was unacceptable.
Two technologies, one integrated solution
Halliburton’s answer came from a collaboration between two of its own divisions. The Testing and Subsea (TSS) group and the Completion Tools (HCT) division had been working together on an integrated barrier system — one pairing a reliable physical barrier with wireless real-time monitoring. This job would mark its first deployment anywhere in the world.
The physical barrier element is the Evo-Trieve retrievable bridge plug. Designed to be set and later retrieved, it provides the downhole seal required to control the well during intervention. What distinguished this deployment was the addition of the DynaLink wireless acoustic telemetry system, integrated with the plug via a single quartz gauge. That gauge continuously measures pressure at the barrier and transmits the data acoustically up the wellbore — no cables, no physical connection to surface required.
Deploying these two technologies together as a unified, continuously monitored barrier solution hadn’t been done before on a CO2 injection well. Neither tool was new on its own. The cross-team collaboration between TSS and HCT was what made the integration possible, and what made this a global first.
How the system was installed and monitored
Installation followed a carefully sequenced process. The 4.5-in. Evo-Trieve bridge plug, fitted with the DynaLink quartz gauge, was run into the well and set below the tubing hanger — positioning it as a shallow barrier that could be verified before the Christmas tree was removed. Once in place, the plug and gauge assembly was pressure tested to confirm the seal.
With the downhole components set, surface monitoring infrastructure went in next. A DynaLink repeater and surface wireless kit were mounted directly onto the wellhead base, picking up the acoustic signal from the gauge downhole and relaying it to the surface. From there, the signal traveled wirelessly to a data acquisition unit housed in an air-conditioned container located away from the well bay area — and that physical separation mattered.
Personnel monitoring barrier integrity in real time didn’t need to be stationed at the wellhead itself. Data flowed continuously to the acquisition unit throughout the intervention, providing an unbroken record of downhole pressure conditions from installation through retrieval.
Real-time data that changed how decisions were made
The operational impact of continuous real-time diagnostics became apparent almost immediately. During the positive pressure test — a procedure that involves pressuring up a gas volume to verify barrier integrity — access to live data helped eliminate the uncertainty that typically accompanies this step. Rather than relying on surface readings alone or waiting for manual checks, the team could observe downhole pressure behavior directly as it happened.
That visibility translated into faster, more confident decision-making on site. When the data confirmed barrier integrity, the team could proceed without hesitation. Questions that arose were resolved quickly using the live feed rather than defaulting to more conservative — and time-consuming — hold points.
The safety benefit extended beyond decision speed. Enabling personnel to monitor the barrier remotely from the air-conditioned container reduced the time workers needed to spend in the well bay area during critical phases of the operation. On a well handling CO2, reducing that exposure is a meaningful gain. The system also captured pressure data in the period before the bridge plug was equalized and retrieved, giving a fuller picture of barrier performance across the entire intervention window.
What this deployment points toward
A single successful deployment rarely transforms an industry on its own, but it does establish what’s possible. This operation in Western Australia demonstrated that a fully integrated, wireless, real-time barrier monitoring system can be deployed on a live CO2 injection well — and that it performs. As carbon capture and storage projects expand globally, the number of CO2 injection wells requiring intervention will grow alongside them. The questions of how to manage those interventions safely, and how to give operators continuous confidence in downhole barrier integrity, are only going to become more pressing. This deployment offers one answer worth watching.
