IOG plc has revised production guidance following drilling fluid losses, production constraints and a planned suspension of operations at its Saturn Banks project in the Southern North Sea.
GUIDANCE
Phase I of the project entails the development of the Blythe, Elgood and Southwark fields.
IOG has revised the expected average gross production rate over H2 2022 from 30-50 mmscf/d to 22-28 mmscf/d.
SOUTHWARK
The Southwark A1 well encountered extensive drilling fluid losses in the 12-1/4″ section in the Bunter Sandstone Formation, and further fluid losses in the Bunter Shale Formation on drilling out of the 9-5/8″ casing shoe.
The company said that this had no bearing on the Southwark reservoir itself which lies “well below this section”.
The fluid losses were not sufficiently cured to drill ahead safely, with the resulting delays reducing the time available before the scheduled arrival of the hydraulic stimulation vessel, added IOG.
The company has suspended the A1 well in order to proceed with hydraulic stimulation and commissioning of the A2 well to deliver Southwark first gas in Q4 as planned, with mid-December as the target date.
IOG is working through several options to mitigate fluid losses and drill ahead at A1 in preparation for completing and producing the well after bringing on A2.
FOUR-WEEK SUSPENSION
Additionally, a defective 6″ offshore valve means that the Saturn Banks pipeline system (SBPS) must be depressurised in order to connect the outer section safely to the 24″ manifold.
The company added it would therefore suspend Saturn Banks production in late October for approximately four weeks, including the November Bacton terminal annual shutdown.
BLYTHE
IOG said that Blythe production was constrained by liquids handling capacity at the Bacton terminal and the need for offsite storage, processing and disposal of saline aqueous liquids produced from the H1 well.
ELGOOD
The company has technically assessed production and reservoir pressure data from the six months since first gas at Elgood.
The production rate recently fell below 10 mmscf/d, faster than anticipated, and “is expected to decline further by year end”.
“The latest analysis indicates that gas is not flowing across the NW-SE oriented intra-field fault to the wellbore as expected.
“As a result, the most likely ultimate recovery from the field is now assessed to be 7.5 bcf, of which approximately 4 bcf has been produced to date.”
Combined flow rates from Blythe and Elgood over H2 2022 to date have averaged 28.6 mmscf/d.