Potentially reaching a depth of around 5,000 metres, well 35/4-3 that was spudded by Aker BP and partners Wellesley (40%) and Petoro (20%) early April is testing the Laushornet prospect in Cook Fm sandstones.
It follows a successful campaign by Equinor last year during which the company also drilled a Cook Fm prospect close to the Garantiana discovery a little further to the west. Well 34/6-5S proved between 8 and 23 MMboe of recoverable oil (see map above).
Brent pinch-out
In this part of the Northern North Sea, the Brent succession is not a drilling target any more, as the sandstone pinch-out line is situated slightly further to the south (see yellow line on the map).
Well 35/4-1 is a good reference point in that regard. Drilled in 1996 by Saga Petroleum, the Brent Group was the primary target, but even though a time-equivalent succession was found, it mostly consisted of silts and very little sand.
Although well 34/4-1 was reported dry, weak hydrocarbon shows were reported throughout the entire section from Eocene to TD.
Shallow gas
Partner Wellesley Petroleum is not new to the area where 35/4-3 is currently being drilled. The company completed exploration well 35/4-2 in 2019, targeting the Songesand shallow gas prospect in Pliocene clinoform sands.
However, the well results suggested a poor quality reservoir and although the interval may be gas bearing – a clear seismic anomaly could be mapped after all – the relinquishment report mentions that an effective seal is probably missing given the sandy nature of the overburden and the lack of a structural trap.
Let’s hope the Cook Formation has got some good news in store for Aker BP and partners.
HENK KOMBRINK
