Well Control Incident Result Of Platform Safety Breaches

Source: Offshore Post

An oil well control incident was the result of multiple safety breaches onboard the Visund Platform, according to Norwegian offshore regulators.

The Norwegian Petroleum Safety Authority (PSA) has handed the platform’s operator, Statoil, a list of non-conformities relating to the incident that occurred back in March 2016.

Visund Well Control Incident

In its report, the PSA claimed that the incident occurred during a well wash, part of the completion process of drilling operations.

Whilst this work was being carried out,  a well-control incident occurred involving inflow from the reservoir (a well kick).

Shortly after the washing process was completed and the well was filled with seawater, the drill string was raised and a volume increase was observed. The well was shut in using a valve on the BOP. Pressure was observed in the well, which finally stabilised at 84 bar.

Valve Failure

The PSA report states that whilst trying to kill the well, it was discovered that both kelly cock valves below the top drive had jammed, one in the closed position, which prevented the use of normal kill procedures. Alternative kill methods were assessed, while attempts were made to operate the valves.

Incident Report

The PSA have reported that no injuries or material damage were sustained during the incident. However, they claim that the consequences could have been very different, and could have led to ‘a complicated and long-lasting kill operation with the potential for escalation of risk’.

Visund Non-conformities

The investigation has identified non-conformities relating to the design of well barriers, verification of well barriers, classification of safety-critical equipment, the maintenance programme for kelly cock valves and the configuration of the sea-bed BOP.

Furthermore, improvement points were identified in respect of well barriers, the risk register in DOP documents, and training and drills.

Statoil has been given a deadline of 18 August 2016 to report on how the non-conformities and improvement points will be dealt with.

Visund Field

The Visund field is located approximately 87 miles (140km) west of Fløro, Norway in blocks  34/8 and 34/7 of the North Sea.

The field is divided between Visund North and Visund South, with all wells being tied back to the semisubmersible Visund A platform.

Production at Visund started on 21st April 1999, with all oil produce being piped to the nearby Gullfaks field for storage and export, whilst gas produce is piped directly back to the Kollsnes Gas Processing Plant on the Norwegian mainland.