A partner on the 44/23-1 Dunquin North exploration well being drilled by ExxonMobil offshore Ireland says the reservoir is water bearing.
Providence Resources, which holds a 16% interest in frontier exploration license 3/04, containing Dunquin, said the primary Lower Cretaceous Dunquin target was encountered and was found to be a thick overpressured carbonate reservoir system. Preliminary analysis indicated the reservoir to be water bearing. Log data indicated a residual oil column, which Providence said suggested a trap had formed at Dunquin North, but that the hydrocarbons had since leaked.
Drilling on Dunquin North started in April, using the Eirik Raude semisubmersible drilling unit, in about 1700m water in the Porcupine Basin about 170km off the south-west coast of Ireland.
It had been described as “a landmark well”, due to being the first to be drilled in the central part of the southern Porcupine Basin and designed to test a new and Lower Cretaceous carbonate exploration play concept.
The well is now being plugged and abandoned. The rig will be demobilized out of Irish waters.
John O'Sullivan, technical director of providence, said: "The Dunquin exploration play comprised two interpreted carbonate features, Dunquin North and Dunquin South. The presence of a potential residual oil column may indicate that hydrocarbon entrapment has occurred at Dunquin North but that the oil has subsequently leaked.
“Top seal integrity had been identified pre-drill as a possible risk for Dunquin North, with fluid escape features and seabed core hydrocarbon anomalies present over the prospect. Notably, the separate Dunquin South build-up appears to have a thicker seal and lacks the significant fluid escape features seen further to the north."
ExxonMobil Exploration and Production Ireland (Offshore) operates and holds 25.5% in license 3/04. Partners are Eni Ireland (27.5%), Repsol Exploracion Irlanda (25%), Providence Resources (16%), Atlantic Petroleum (Ireland) (4%) and Sosina Exploration 2%).
Image: The Eirik Raude semisubmersible drilling unit.