When Petrofac was appointed as Well Operator and main contractor for the latest phase of the Thames decommissioning project, the pressure was on to relive the success it delivered in 2016 for Tullow Oil.
Back then, a rig-less approach to working, new pipe severance and recovery techniques had delivered more than $2.5million in savings on the Horne and Wren phase II decommissioning project.
On Tullow Oil’s latest scope to decommission seven subsea wells, Petrofac’s Well Engineering team addressed an entirely different set of challenges to deliver project savings of over US$4million. An achievement which benefited not only Tullow Oil, but the wider supply chain.
“It’s quite normal with legacy infrastructure to find that the original tree and wellhead equipment is no longer supported”, explains Wells Manager, Angus Hunter. “In addition, late life wells often have unknown pressure regimes. This combination presents a really interesting challenge for us to address as Well Operator.
“It’s an obvious point, but at this end of the asset life cycle, the focus on cost and schedule is more acute than ever. Our job is to tackle these challenges on behalf of our client, in the most efficient way possible”, he continues. “We were responsible for all sub-contracted services on the project. This meant Tullow had just one interface, but perhaps more importantly, it enabled us to take a holistic approach that allowed us to optimise operations and maximise collaboration across the supply chain in order to deliver even greater efficiency.”
It was this collaboration, that Angus believes contributed toward successful completion of the plug and abandonment programme ahead of schedule and significantly under budget.
“We developed a shared approach to risk and reward, meaning those involved were fully invested in safely beating the schedule.
“We worked together to implement alternative solutions to mitigate key risks and control project expenditure, from the deployment of air divers from the rig instead of utilising a Dive Support Vessel, to the novel application of a managed pressure drilling spread to mitigate the well re-entry risks of unknown pressure regimes.
“Together with our key contractors we also continually improved operational efficiency to reduce the campaign schedule, and overall made considerable savings which were shared across the supply chain.”
To find out more about Petrofac’s Well Engineering capability, click here.