By OGJ editors
HOUSTON, Nov. 29 -- Apache Corp.’s appraisal of the 1976 Spar discovery off Western Australia flowed gas-condensate at such a rate that partner Santos Ltd. said the volume of recoverable gas “is expected to be significantly greater than the 335 petajoules gross previously stated.”
Apache, operator of the WA-4-R permit in the Carnarvon basin since the end of August, tested the Spar-2 appraisal well at a facilities-constrained rate of 58 MMcfd of gas and 950 b/d of condensate on a 1-in. choke.
The well, which cut 55 m of net pay in the primary target Upper Barrow reservoir, has been completed as a producer. The site is 70 km west of Varanus Island.
Santos said the well also intersected 40 m of net gas pay in several sands in the deeper secondary exploration target, the B Reticulatum zone. That zone drillstem tested 5 MMcfd and 6 bbl/MMcf through a 1-in. choke from a 12-m section.
Apache’s Australia subsidiary will bring gas from Spar field and nearby Halyard field to Western Australia’s domestic gas market via an existing Apache-operated pipeline 10 miles southeast of Spar-2 and through the Varanus Island processing and transportation hub.
Halyard is to start up at 50 MMcfd in the second half of 2011, and Spar will follow in late-2012 as capacity opens on the island.
Apache owns a 55% interest in WA-4-R and adjacent WA-13-L, where Halyard is located. Santos owns the remaining interest.
Spar-2 was completed over a perforated interval of 131 ft within 163 ft of high-quality gas pay in a single zone at the top of the Barrow Group formation. The appraisal is 1 mile southwest of the Halyard-1 discovery and 18 miles southwest of Apache’s John Brookes platform.
Halyard-1, drilled in 2008, test-flowed at a peak 68 MMcfd of gas and 936 b/d of condensate from 91 ft of net pay in the Cretaceous Halyard sandstone.
On release from Spar-2 the rig will move to the nearby WA-290-P permit to drill the Apache-operated Zola-1 exploratory well in which Santos has a 24.75% interest. Apache and Santos plan to drill the Beam prospect in 2011 located in WA-13-L.
Santos purchased Spar after Chevron Australia determined it was surplus to the Greater Gorgon LNG development (OGJ Online, Sept. 20, 2008).