AWE Ltd., Sydney, operator of the Waitsia natural gas field project onshore Western Australia’s North Perth basin, has released an independent report that certifies the 2P reserves are sufficient to supply 100 terajoules/day of gas for 10 years.
Perth consultancy RISC Operations Pty. Ltd., appointed by AWE earlier this year, has estimated the Waitsia field contains 2P reserves of 460 bcf of gas, a figure that is 34% higher than AWE’s estimate of 344 bcf in June.
The field lies in licences L1/L2. The new estimates have been limited to the Kingia and High Cliff Sandstone reservoirs. They do not include gas in the Dongara and Wagina formations, the Irwin River Coal measures, or in the associated Senecio, Synaphea, and Irwin fields.
Consequently AWE says RISC’s report not only certifies current reserves, but confirms that Waitsia field has significant upside potential. At the moment the company estimates 2C contingent resources for Waitsia field are 630 bcf.
Although pleased with RISC’s findings, AWE has decided to retain its June reserves estimate on its books until after completing further seismic studies, more appraisal drilling, and flow testing and analysis.
Two appraisal wells will be drilled next year, concentrating on the southeast extent of the structure. If successful, these will be completed as production wells.
Production from Waitsia Stage 1A at 10 terajoules/day of gas began last month (OGJ Online, Aug. 29, 2016). The company says that production data from this phase of the project and the new reserves estimates will add impetus to the gas marketing efforts with the aim of signing contracts for supply ahead of a final investment decision for Stage 2 full production program.
The Stage 2 initial plateau rate of 100 terajoules/day could potentially be achieved from six wells, including the three appraisals already drilled.
A total of 15-20 wells are likely to be drilled during the fields expected 20-year life.
The wells will all be connected to a central gas processing facility and sales gas sent to market using existing nearby pipelines. The gas is 93% methane, which means that minimal processing will be required.
AWE holds equal interest in L1/L2 with Origin Energy Ltd., also of Sydney.