This occurred last week during a well wash operation.
An inflow and a pressure increase were both recorded in the well’s annulus. Operator Statoil subsequently stopped production and began demanning the Visund A semisubmersible platform.
Although the BOP proved to be intact, problems were reported in operating shutoff valves at the top of the drillstring.
However, no hydrocarbon leaks resulted and the situation was normalized the following day.
PSA’s focus will be on Statoil’s planning and execution of the well operation. It will seek to clarify the chain of events and identify underlying causes.