Guillemot North-West Field: Comparison of Seismic and Ultra-Deep Resistivity Imaging on a 2024 Infill Producer

The Guillemot North-West field is a mature oil field with the reservoir consisting of sandstones in the Tay Sandstone Member of the Horda Formation. A new infill oil producer as well as an opportunistic pilot hole were drilled in 2024.

21/24-W7 was drilled to de-risk an infill opportunity using Logging While Drilling (LWD) to assess reservoir properties and hydrocarbon saturation, and to calibrate the seismic response at this location. 21/24-W7Z was drilled and completed as an horizontal oil producer, utilising LWD with Ultra-Deep Resistivity (UDR) extensively to optimise the landing of the well in the reservoir, and ensure the horizonal section remained in the reservoir while maximising stand-off from the oil-water contact.

Seismic data from 2012 (Polarcus survey) brightens with hydrocarbon-filled sand. However, the seismic response of the hydrocarbon interval is generally tuned (overestimates hydrocarbon thickness) and does not discriminate the proportion of oil and gas. The pilot hole confirmed a hydrocarbon filled to base untapped accumulation. The UDR inversion and the LWD logging acquired from the producer provided a detailed image of top reservoir, base reservoir, current gas-oil and oil-water contacts and overall confirmed the interpretation, detuning and stretching approach of the seismic data.