Tag Oil Ltd., Vancouver, BC, is under way with a three-well exploratory program to examine the deep Eocene-Paleocene Kapuni sandstone formation onshore in New Zealand’s Taranaki basin.
The company has drilled the Cardiff-3 well, spudded Sept. 2 on PML 38156, to 3,918 m enroute to its projected total depth of 4,900 m, expected to take 14 more days. The company has received regulatory approval to stimulate the well if results warrant.
Economic factors for completion, which would likely include a hydraulic-fracture stimulation, will consider net gas pay thickness, indicative in situ permeability, and the interpreted volume of original gas in place that could be accessed with this well bore, Tag Oil said.
In the event of a success, three wells would be needed to fully develop the midrange prospective resource estimated at 160 bcf of gas and 5.49 million bbl of condensate. The midcase resource for the three Kapuni prospects totals 476 bcf and 18 million bbl.
Careful study has shown the formations being targeted for potential hydraulic fracturing at Cardiff-3 to be completely sealed by more than 4 km of impermeable rock. If hydraulic fracturing is required, new generation plant-based fracing fluid will be used and all fluids and water will be contained in a closed system, the company said.
The Cardiff structure is a 12 by 3 km anticlinal trap. Gas-condensate was discovered in the Cardiff-1 (Shell-1991) and Cardiff-2A (Austral-Pacific 2002) wells: Cardiff-2 encountered 12 m of net pay in the uppermost McKee formation of the Kapuni Group sands and flowed more than 3 MMcfd and 100 b/d without fracture stimulation on a short-term test.
More significant prospective resources exist in the deeper K1A and K3E zones, the primary targets in the Cardiff-3 well, where strong gas shows were encountered over a gross 600-m interval in the Cardiff-2A well. These went untested due to mechanical problems during drilling, but the lower Kapuni Group formations are the primary producing intervals in nearby 1.4 tcf and 65 million bbl Kapuni field.
