Safety body starts investigation following Gjøa well incident

Norway’s offshore safety watchdog, the Petroleum Safety Authority (PSA), has started an investigation of a well incident on the Gjøa field when the drill string became stuck fast and blocked the blowout preventer (BOP).

The PSA said on Wednesday that the incident occurred during
drilling of production well 35/9-G-4 H on the North Sea field by the Deepsea
Yantai drilling rig on 20 September 2020.

According to the safety body, the well had already entered
the reservoir section when the string became stuck in the formation while it
was being pulled out. During efforts to free it, the string separated into two
sections.

These parts of the string blocked the BOP so that the latter
was unable to close and prevent a potential well stream leak. No discharges
resulting from the incident have been reported.

Neptune Energy reports that a cement plug has been inserted
against the reservoir so that barriers have been restored. Work is still underway
to remove the two drill string sections from the BOP.

The PSA regards the incident on Gjøa as serious, and an
investigation team will look at the planning of the well and implementation of
the drilling operation up to the point when the incident occurred.

The main objective of the investigation is to identify the
causes of the incident and possible lessons to be learnt and to share this
information with the industry.

During its investigation, the PSA will review the course of
events, assess the actual and potential consequences of the incident, identify
direct and underlying causes, identify nonconformities and improvement points
related to the regulations, apply necessary enforcement powers to correct possible
regulatory breaches, make public its findings, and contribute to experience
transfer to and learning by other players in the petroleum sector.

The Neptune-operated Gjøa field is developed with a
semi-submersible production facility and includes four 4-slot templates, as
well as one single-slot template on the P1 segment.

Production started in 2010, and in 2019, Gjøa was given the
green light for the redevelopment of the P1 segment. It is worth noting that
the Vega and Vega Sør fields are also tied-back to Gjøa for processing and
further export as well as Wintershall Dea’s Nova.

As for the rig, the Deepsea Yantai – formerly known as the Beacon Atlantic – is of GM4D design and is capable of harsh environment operation and is winterized for operation in Arctic areas.

It is worth noting that CIMC Raffles and Odfjell Drilling
signed a four-year management agreement last year, under which Odfjell Drilling
would manage and operate the rig.