Exploration

The primary objective of the SGJV is to evaluate the unconventional resource potential of the lower Arthur Creek Formation, seeking a continuous gas resource.

The first phase of exploration commenced in 2013. Exploration activities included acquisition of 974 km of 2D seismic, followed by the drilling of two wells, Whiteley-1 and Gaudi-1.

Whiteley-1 Well, ATP 912

Drilling of the unconventional gas well, Whiteley-1, commenced on 20 July 2014. This well was the first of a two well programme of unconventional gas exploration operated by Central. The planned depth for this well was 1,920 metres but for operational reasons the well was suspended above the target section at 1,141 metres.

Gaudi-1 Well, ATP 909

Drilling of the unconventional gas well, Gaudi-1, commenced 14 September 2014. As with Whiteley-1, the primary objective was the Lower Arthur Creek Formation. A total of 282 metres of core were successfully retrieved from the Lower Arthur Creek Formation and Thorntonia Limestone, before the well reached a total depth of 2,430 metres in basement. Good gas shows were recorded in the Lower Arthur Creek Formation during drilling and selected core segments were placed into sealed canisters for desorption analysis, from which the adsorbed gas content of the Lower Arthur Creek Formation has been determined. A comprehensive wireline logging suite was run to TD and the well was cased and suspended. Ongoing integration of core and log data will progress the understanding of the unconventional potential of the Lower Arthur Creek Formation.

Exploration efforts have included analysis of legacy wells in conjunction with the drilling of Gaudi-1 and Whiteley-1. These studies confirm there are at least four play types operating in the SGB, being:

  • Lower Arthur Creek unconventional gas target. The company aims to complete the drilling of Whiteley-1 well to better understand distribution of key unconventional reservoir parameters;
  • Tight gas target, as demonstrated in Gaudi-1 where gas is reservoired in tight carbonates. The extent and variability of the play is to be determined, forms a target of interest;
  • Hydro-Thermal Dolomite play: A new play has been identified, bearing a good resemblance to analogues in the US; and
  • Conventional gas such as discovered in Ethabuka-1, which is a large structure requiring appraisal by flank wells to determine the extent of the gas column and reservoir distribution.