StatoilHydro’s Linerle prospect was probably the first in the world to use information gathered by seabed logging (SBL) to verify the presence of an oil reservoir prior to drilling.
Four SBL lines were acquired by ElectroMagnetic GeoServices (EMGS) during 2003 to cover the Linerle prospect in the Norwegian Sea, one being tied to the 6608/11-3 l (Blåmeis) dry well and one to the Norne oil field.
The two remaining lines covered the Linerle prospect.
From well information in the Norne area, potential hydrocarbon-filled reservoir intervals were expected to elicit resistivities of about five to 50 ohm-m. The expected average was 10 ohm-m for oil-filled lower Jurassic sandstones, which were predicted for the Linerle area.
Water-bearing sandstones and overburden sediments were expected to yield resistivities in the range of 0.5 to two ohm-m.
The measured values for line 03 are shown in the figure (pdf-file) together with the extent of the possible Linerle reservoir (as mapped from seismic data), which is shown by the red bar. The increases in SBL magnitude responses were interpreted as reflecting a change in subsurface resistivity.
Occurring close to the predicted delimitation of the Linerle prospect, the maximum values were thought to be due to hydrocarbon accumulations in a 50-100-metre-thick Jurassic sandstone of about 10 ohm-m, roughly 1,000-1,500 metres below the seabed.
Subsequent drilling revealed the presence of a 20-metre-thick oil column of about 20 ohm-m at a depth of 1,275 metres.
