Extending Valhall’s lifetime with well plugging
Plugging wells is a key part of the modernisation of the Valhall field centre, and thus also in the ambition to produce a total of two billion barrels from the giant in the North Sea.
Plugging of wells at the Valhall field centre has been completed six years earlier and more than five billion Norwegian kroner cheaper than originally planned. The work has also been delivered without serious incidents.
The Maersk Invincible drilling rig left the Valhall field centre last week. That marked the end of several years of plugging operations on the field. A total of 30 old wells from the original drilling platform (DP) have been plugged over the course of three campaigns since 2014.
Aker BP is operator and Pandion partner in Valhall. First oil flowed from the field in 1982. Since then, over a billion barrels of oil equivalent have been produced from the area – more than three times as much as expected at start-up.
Ole Johan Molvig, Valhall Asset Manager, said:
“Plugging wells from the shutdown drilling platform is an important part of the Valhall modernisation. There are considerable remaining resources in the Valhall area, and our vision is to produce from the field up to 2050. We will maximise value creation from the area through new wells, flank developments and new technology.”
The original QP accommodation platform was removed in the summer of 2019. Over the course of the next few years, the original drilling platform and process platform will also be removed from the field centre. The original Hod wellhead platform, south of the Valhall field, will also be removed and replaced with a new.
The first plugging campaign in 2014-2016 was conducted by the Maersk Reacher rig. Maersk Invincible carried out the last two campaigns in 2017-2018 and in 2020-2021.
Originally Aker BP estimated the operational time of the plugging campaigns to 10 years at a cost of NOK 15.5 billion. The work was completed in 4 years and at a cost of NOK 10.1 billion.
Tommy Sigmundstad, SVP Drilling and Wells in Aker BP, said:
“The work to plug the wells has been a success through three major campaigns. The plugging has been carried out safely and efficiently. We have an unrelenting focus on improvement, and that has paid off in shorter operation times and reduced costs. Our alliance partner Maersk Drilling has been a key factor in all the campaigns.”
The last plugging campaign on Valhall was delivered by the jack-up rig alliance between Maersk Drilling, Halliburton and Aker BP from September to March.
The original plan was to spend 72 hours per well to plug the top well section. During this winter, the alliance reduced this to as little as 33 hours. Overall, the alliance has delivered the entire scope of work more than two months faster than planned. Because of this, the Valhall asset team was able to rapidly mature a decision on new wells on Valhall Flank North, which means more work for the alliance.
