The figures refer to both its Wintinna East EL 3326, for which an estimate was provided in June, and Weedina EL 3325 permits, following an independent review of the previous drilling data by consultancy Geos Mining.
The study estimated the EL 3326 permit contained one billion tonnes of inferred resources of sub-bituminous coal in six seams in the south-central area of the licence.
Sapex managing director Andrew Andrejewskis said the results indicated the permit had the potential to contain 300-900 billion cubic feet of CSM resource, based on a notional gas content of 300 cubic feet per tonne
"When combined with the results of the study on EL 3325 (Wintinna East) - which was reported on 25 June this year - the two ELs combined have an in-place potential for CSG of between 507 billion cubic feet to more than 2 trillion cubic feet," he said.
"This combined CSG estimate only covers the areas of EL 3325 and EL 3326, and does not include the remainder of the Arckaringa Basin which is held by SAPEX in seven petroleum exploration licences covering 65,000 square kilometres."
Andrejewskis said Sapex would explore the basin's CSM potential in the next few months.
But he said these activities were separate from Linc Energy's work to identify areas in its South Australian acreage that could be suitable for underground coal gasification and coal-to-liquids projects.