US Gulf developments advance as Murphy sanctions Banjo/Cello and Who Dat expansion moves toward FID

Operators in the US Gulf of Mexico are advancing a mix of new developments, infill drilling and infrastructure mitigation efforts.

Murphy sanctions Banjo and Cello development

Murphy Oil has approved development of the Banjo and Cello fields in the US Gulf, with startup planned for fourth-quarter 2027, according to the company's latest quarterly report.

Chinook well advances toward first production

Elsewhere in the region, the company’s Chinook #8 development well has spudded and should go onstream later this year, at an initial production rate of 15 MMboe/d.

Who Dat East development targets Q3 FID

Harbour Energy, the new operator of the Who Dat Field, following its takeover of LLOG, says the partners are aiming to take FID on the Who Dat East development during the third quarter.

A second rig is due to arrive before year-end, with the goals of speeding up high-returns drilling and completion activity.

Production declines tied to riser issue

Partner Karoon Energy said in its latest results update that production from Who Dat has been averaging 18,300 boe/d, down from 29,100 boe/d in fourth-quarter 2025.

The lower volumes were caused by a shut-in of one of the two risers connected to the E-manifold after it developed a minor leak in February. The adjacent riser was also then shut in to fully isolate production from the leaking riser.

Mitigation program underway to restore output

Assuming a successful outcome to a planned mitigation program, about 55-75% of the production could be restored by mid-year. This involves diverting hydrocarbons through the other E-manifold flowline and riser, and through optimization activities. A full restoration of normalized output should follow during the second half of 2027.

However, the impacted riser will need to be replaced.

Sidetrack activity to support near-term volumes

A current sidetrack of the A1 producer well should be completed and ostream later this year.

Another sidetrack should spud during the second half of the year, subject to a final technical assessment, and joint venture and regulatory approvals. This could further help mitigate the impact of the riser issue on Who Dat’s 2026 and 2027 production.