The JV, which operates petroleum exploration licences 2, 5 and the Camden coal seam methane field, has a licence obligation to drill a conventional exploration well prior to end of permit year 2008.
Sydney Gas today said the JV identified the Marrangaroo Formation, a conglomeritic, alluvial sandstone found towards the base of the Wilton Formation.
“The prospective structure is a tilted wedge [with] the point of the wedge rising to the south,” the company said.
“It has been mapped using a combination of seismic and previous well intersections.”
The company said although shallow today, the Marrangaroo has not been previously exploited because it does not form the simple anticlinal trap, which is the typical geological target.
Sydney Gas said Marrangaroo also had not been exploited because it has a palaeo-history of much deeper burial. As a consequence, the sandstones form an intrinsically poorer quality reservoir.
The company said the identified structure is extensive at an estimated 600 square kilometres, with average thickness of 5m and in some areas, possibly as much as 12m or more.
“Very conveniently most, perhaps all, of this structure lies beneath the existing Camden development, which makes it comparatively easy to access, and it is only 150-250m deeper than the Bulli coal, which makes for highly cost-effective exploration,” Sydney Gas said.
“If a significant portion of this structure is gas-bearing and producible, it would form a material addition to the existing, shallower CSM development.”
The JV has identified four potential locations in the Camden development where wells may be drilled to assess this conventional exploration target and said it now plans to progress to “proof of concept”.
Once the nearby Curran’s Hill corehole is completed, the parties intend to move Rig-28 to the first of these locations, a well re-entry site (AP01).
Subsequent to this well and possibly a second re-entry well, the rig will resume the ongoing exploration program.
Operator of the Camden Gas project, AGL Energy, in a 50:50 JV with Sydney Gas, will be responsible for drilling the exploration well.
