The upgrade means AWE's plan of delivering 100 terrajoules a day for 10 years is now within easy reach, with double the reserves needed.
Energy News confirmed this morning that the upgrade makes Waitsia bigger than Dongara, which has produced about 450 billion cuibic feet of gas to date.
The Warro field and potentially the Whicher Range field are likely to be larger discoveries, but are yet to be commercialised.
There are also larger accumulations identified in the Canning Basin, like the Valhalla/Asgard tight gas accumulatuion now owned and operated by Mitsubishi, which has contingent resources of 1.5Tcf, but is not yet commercial.
AWE said there was now also a "substantial additional upside" demonstrated by the new gross 3P reserve estimate of 1220PJ.
"The additional reserves identified by this review are more than double the reserves required for this project, and provide opportunities for significantly increased near term field production and longer field life," managing director David Biggs said.
The independent assessment is closely aligned with AWE's own internal estimates from work done to date.
The recent flows from the Waitsia-3 and Waitsia-2 wells were much higher than expected at 50 million cubic feet per day and 39MMcf/d respectively, and AWE now plans to test Waitsia-4 before the end of the month.
This new data from RISC and the flow tests will provide further information for gas buyers, Briggs said.
Biggs said that subsurface appraisal is almost complete and the front end engineering and design process is looking at an end of month plan for final tender submissions, putting AWE in a position to consider final investment decision by year's end, provided they can secure enough gas sales agreements.
RISC's analysis was confined to only the Kingia and High Cliff Sandstones, leaving out Dongara, Wagina, Irwin River Coal Measures and the associated Senecio, Synaphea and Irwin fields.
Many things led to the estimate upgrade: Waitsia-3 and -4 wells encountered substantially thicker sections of high quality Kingia reservoir and the wells' results allowed a transfer of contingent resources in the Kingia reservoir to the reserves classification.
After this the 3D seismic data volume was reprocessed and re-depth converted using this new well data with the observed thicker reservoir and refined depth conversion also resulting in an estimation of greater thickness, rock volume and improved reservoir properties resulting in a significant increase to the gas initially in-place and recoverable reserves.
Just last week RBC Capital Markets Sydney-based analyst Ben Wilson had looked at AWE's case and saw its plan of 100TJ/d for 10 years within easy enough reach given at least two of the drilled appraisal wells were over delivering.
RBC modelled just 11 wells for a Waitsia field development with a 10-year plateau rate of 100TJ/d including the five wells already drilled, and that AWE and partner Origin Energy - soon to be Beach Energy - would still need to find another gas sales deal.
AWE was trading at 56c this morning.