New Zealand Oil and Gas and its PEP 38460 partners announced that the Tui-1 well had encountered a gross oil column of 10m within the Kapuni F sands, of which 100% was net oil pay in excellent quality reservoir rocks.
"It's beautiful, superb rock with good permeability and porosity," NZOG exploration manager Eric Matthews told EnergyReview.Net.
Though Matthews would not be drawn on possible flow rates, it is believed Tui-1, which is now being plugged and abandoned as scheduled, could have flowed at substantially more than 3000-4000 barrels a day.
However, Matthews said Tui-1 looked to be a marginal discovery, though if NZOG proved up possible reserves figures by successful subsequent appraisal drilling then the field should definitely prove commercial.
Pre-drill estimates of recoverable oil from the F sands had been about 50 million barrels, though not from this single well.
Mathews said the implications of oil charge in the Kapuni F sands were great. "It looks as if our theory of oil migrating west of Maui can now be substantiated. The presence of oil rather than gas has upgraded the other prospects of the block."
This meant other prospects within the licence, such as Hector, Tahuroa and Pucker, could prove to be major new oil plays, he added.
Matthews said the partners could move as early as next month to acquire 3D seismic over the Tui prospect with a view to further delineating the prospect and possibly drilling some appraisal wells.
Tui-1 reached its total depth of 3903m and was currently running wireline logs, before being plugged and abandoned.
As previously reported, the primary objective of the well, the Kapuni D Sands, was encountered slightly high to prediction but was associated with only minor oil shows and low levels of cuttings gas. Subsequent wireline logging has confirmed that no producible hydrocarbons are present in this interval.
When the Kapuni F Sands were encountered at 3655m, elevated cuttings-gas and hydrocarbon fluorescence were observed over the uppermost 20m of the sand. These observations were interpreted to indicate gas but subsequent evaluation of the wireline data, including MDT fluid sampling, indicated the 10m oil column.
