Shell is "proposing changes" to its plans for developing the high-pressure, high-temperature Jackdaw field in the UK central North Sea after its initial proposals were rejected by the UK offshore environmental regulator.

In a letter published Thursday on the UK government website, the Offshore Petroleum Regulator for Environment & Decommissioning (Opred) confirmed for the first time it had turned down Shell's initial plans for developing the gas and condensate accumulation, a proposed tie-back to the operator's Shearwater platform.

Opred also noted in the letter, dated 14 October, that Shell is "proposing changes" to the project, although no details were given.

Opred then went on to ask Shell to provide it with further information about the "proposed changes to the project".

Climate-impact details sought

"The further information should address, in particular, any difference that the proposed changes may make to the impact of the project on climate (for example the nature and magnitude of greenhouse gas emissions) and any features of the project or measures envisaged in order to avoid, prevent reduce or offset likely significant effects on the environment," Opred wrote.

A Shell spokesperson told Upstream: "We continue to work with the regulator to explore options for developing Jackdaw."

Shell confirmed last week that Opred — part of the Department for Business, Energy & Industrial Strategy — had rejected its plans for Jackdaw after a consideration of its environmental statement for the project, but Opred only confirmed its ruling today.

Earlier this year, the regulator asked Shell for further information as to why it had not selected Harbour Energy's Judy platform as the tie-back host facility, "given that cost and technical viability don’t render the alternative unfeasible".

Opred argued at the time that Shell's environmental statement said that Shearwater offered both "a slightly lower risk option in terms of brownfield modifications" and "that there were no significant environmental differentiators between the two options".

'Justification seems odd'

However, Opred said: "The latter justification seems odd given the clear benefits of avoiding significant offshore vent emissions from the amine unit and a shorter pipeline length (and seabed disturbance) requirement to that of Shearwater."

Shell had been hoping to reach a final investment decision this year on Jackdaw to bring the field on stream in the third or fourth quarter of 2024, about a year later than originally planned due to the Covid-19 pandemic.

Gas output is expected to peak at 4.85 million cubic metres per day with condensate output set to peak at about 6000 barrels per day, also in 2025, according to the environmental statement for the scheme.

Shell has been investing considerable sums of money into its Shearwater assets as part of what the company calls its Central Graben strategy, which will also link fields such as Fram and Arran back to Shearwater.

This strategy involves a simplification of the production process on Shearwater while also rerouting gas exports that currently travel along the dry-gas Shearwater-Elgin Area Line (SEAL) network to the wet-gas Shell Esso Gas & Associated Liquids (SEGAL) system through the 290-kilometre Fulmar Gas Line (FGL).