The well will appraise the West Erregulla tight gas field, Irwin River Coal Measures, several unconventional shale formations, and will now be deepened to target the conventional Permian age Kingia sandstone, believed to be equivalent to the nearby Waitsia field, recently discovered by AWE and Origin Energy.

 

The primary target for the well are the Permian Wagina and Dongara sandstones which it is hoped modern technology may be used to help unlock the 1990 discovery.

 

With success, Warrego will suspend the well and design a testing program, and while the original discovery was tight the company says hydraulic fracturing is not envisaged at this stage. 

 

Warrego has been working on EP 469 since it was awarded the right to explore the block in 2008, and needs to complete the well before permit expiry in 2019. 

 

The junior is still to secure a rig, but has had a number of discussions with drilling contractors, and if all goes well is expected to use the same rig being used this year by AWE and Norwest Energy in a range of planned wells across the basin, including the nearby North Erregulla Deep-1 well, which Empire Oil & Gas hopes to drill looking for similar targets as Warrego.

 

Warrego's environmental plan suggests the drilling will take around five weeks, with the well suspended by June.

 

The deep Kingia/High Cliff prospect was defined by 3D seismic in 2014 and sits at a depth below 4000m.

 

Total depth is planned at 4925m. 

 

The company had originally planned to drill the well in 2015-16, but suffered delays in completing its 3D seismic. 

 

West Erregulla has been assessed to contain an estimated 185 billion cubic feet of gas-in-place within the tight gas field and a potential 9Tcf GIP unconventional upside potential in the Permian Carynginia and Triassic Kockatea Shales.

 

Numbers have never been released for the deeper targets, which only came to notice after Origin and AWE drilled the Senecio-3 well in 2015.

 

The West Erregulla field was originally discovered by Barrack Energy, which drilled an anticline in the Dandaragan Trough, 11 kilometres west of WAPET's 1966 Erregulla-1 well.

 

West Erregulla-1 well intersected a 31m gross gas column between 3964-3995m in the Permian sandstone, with a net pay of 26m and average porosity of 7%.

 

Two drill stem tests were run in the well recovering only minor gas to surface and the well was plugged and abandoned, with peak flows of just 18,000 cubic feet.

 

West Erregulla is the first of several seismically mapped structures of interest to be targeted within EP 469, Warrego has said.