Early assessment of appraisal drilling results indicates a lowering in the resource estimate for the 7225/3-1 natural gas discovery in the Barents Sea offshore Norway, reports the Norwegian Petroleum Directorate.
At the time of the discovery, called Norvarg, the preliminary resource estimate was 350 bcf-1.7 tcf of recoverable gas (OGJ Online, Aug. 10, 2011).
The Ocean Rig Leiv Eiriksson semisubmersible drilled the appraisal well to a vertical depth of 2,171 m below the sea surface in 383 m of water about 5 km from the discovery well.
The well bottomed in the Lower Triassic Klappmys and will be plugged.
It encountered natural gas in the Middle Triassic Kobbe formation with varying reservoir quality. The reservoir has better porosity in the appraisal well than in the discovery but similar permeability and productivity.
The appraisal well encountered water in the Middle Jurassic Sto reservoir, a secondary target that yielded gas in the discovery well.
Two formation tests of the Kobbe in the appraisal well flowed at a maximum rate of 175,000 standard cu m/day through a 52/64-in. choke. The operator collected extensive data and samples and installed pressure sensors.
The rig will move to Production License 537 in the Barents Sea to drill OMV Norge AS 7324/7-1 S wildcat.