NZOG said yesterday that the survey – a single 15km-long line – was to further delineate the petroleum potential of the Felix and Opito-Updip prospects that NZOG believed could hold up to 70 million barrels or more of recoverable oil within the onshore-offshore licence PEP38729.

Company general manager Gordon Ward told EnergyReview.net that a lack of accurate velocity mapping over the area – a remote and rugged coastal strip at the northern end of Taranaki – had hindered earlier exploration there, including the 2002 wildcat Opito-1 well that had minor hydrocarbon shows.

“The Kapuni C sands come ashore at this part of Taranaki and when we drilled Opito-1 we thought we had correctly identified the structure but we should have gone up-dip as an overthrust formed a seal,” Ward said.

“We need to determine if it’s worthwhile drilling another well updip, perhaps going through that overthrust.”

Eocene-aged Kapuni C sands are widespread over offshore and onshore Taranaki and are the main producing reservoir at the more southern offshore Maui field.

“The GNS survey should be finished by the end of the month and analysis completed after that,” Ward said.

“Then we should be in a position to decide whether we need more detailed seismic or have enough information to drill a second well.”

Ward said the refraction survey varied from conventional seismic reflection methods in that it was designed to provide seismic velocity information rather than structural imaging.

The survey would be over both the Felix and Opito-Updip prospects, which could be linked or might be separate structures, he added.

PEP 38729 interests are: NZOG (operator and 75%) and Origin Energy (25%).