Southern Georgina Basin

Tenement Information

map Southern Georgina

ATP 909, ATP 911 and ATP 912, originally awarded to Central 11 March 2013 for four years, have received a special statutory extension of the term, work program and relinquishment conditions for an additional 2 years from 10 March 2017 to 10 March 2019.

Central is currently in negotiations with the CLC in relation to EP(A)132.

Tenement Area
(km²)
Location Operator CTP Consolidation Entity Other JV Participants
Registered
Interest
(%)
Beneficial
Interest
(%)
Participant
Name
Beneficial
Interest
(%)
ATP 909 2,672 Georgina Basin QLD Central 90 90 Total 10
ATP 911 4,330 Georgina Basin QLD Central 90 90 Total 10
ATP 912 7,365 Georgina Basin QLD Central 90 90 Total 10
EP(A) 132 9,587 Georgina Basin NT Central 100 100

Southern Georgina Joint Venture

The Southern Georgina Joint Venture (SGJV) is operated by Central under a farmout agreement with multinational energy company, Total, and comprises a three stage exploration project. Central has responsibility for all activities during the exploration phase.

Description and Geology

The Southern Georgina Basin comprises a succession of Neoproterozoic, Cambrian, Ordovician and Devonian carbonate and clastic sediments up to 5,000 metres in thickness deposited in a broad northwest–southeast depression.  Several structural phases have shaped the basin, the most important of these events being the Petermann and the Alice Springs orogenies.  The Toko Syncline formed in the later part of the Alice Springs Orogeny by northerly thrusting of the Arunta Block. The basin was extensively eroded after uplift in the east.  The basin has two established Middle Cambrian source rocks, one developed at the base of the Lower Arthur Creek Formation, and the other within the Thorntonia Limestone.  These source rocks are responsible for ubiquitous oil and gas shows in some 30 wells drilled in the basin.  A sub-commercial gas flow of ~200 Mcfd from the Coolibah formation was recorded in the exploration well Ethabuka 1.

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.