IOG plc encountered “abnormally pressured gas and oil influx” while drilling the Blythe H2 development well at the Saturn Banks project in the southern North Sea.
H2 WELL
The H2 well is being drilled by the Shelf Perseverance jack-up drilling rig under IOG’s contract with Shelf Drilling (UK) Ltd.
Petrofac is the well operator.
IDENTIFIED RISK
The well spud on 5 March and was expected to take approximately three months to drill, complete and hook-up, subject to operational risks.
“The H2 well was successfully drilled to the Basal Zechstein sequence,” said IOG in a statement.
“However, while drilling through the Hauptdolomit formation within the Zechstein, an abnormally pressured gas and oil influx was encountered, with associated drilling fluid losses.
“The risk of such a well control challenge was identified during planning and is being safely managed by Petrofac and Shelf, in collaboration with the IOG team.
“However, this now looks likely to impact the expected well duration, potentially by up to four weeks, while the associated cost impact will depend largely on the speed of resolution.”
OPTIONS
IOG added that the influx from the Hauptdolomit contained non-commercial quantities of oil and gas and was unrelated to the target Rotliegendes gas reservoir which is over 500 ft deeper and isolated from the Hauptdolomit.
The well has been displaced to a mud weight above the formation pressure.
The company is assessing its options including isolation of the influx zone with cement and, if necessary, side tracking of the well.