AWE Raises WA's Perth Basin Gross Recoverable Gas to 700 Bcf

The Waitsia-2 appraisal well was drilled to a total depth of 11,581 feet (3,530 meters) Measured Depth below Rotary Table (MDRT). The primary and secondary targets were successfully intersected with high gas shows observed in the Kingia and High Cliff Sandstones as well as the Irwin River Coal Measures and the Carynginia Shale. Wireline logs, pressure data and samples confirm the presence of a substantial gas column and extension of the Waitsia field to the southern culmination of the mapped structural closure.

The Waitsia-2 data have been integrated with the information from the Senecio-3 and Waitsia-1 gas wells to estimate reserves and revised contingent resources for the Kingia/High Cliff Sandstone reservoirs over the entire Waitsia field. Sufficient technical data have been collected to justify the booking of reserves for the good quality conventional reservoirs in the areas around Senecio-3, Waitsia-1 and Waitsia-2. Conventional good quality gas pay is defined as reservoir having greater than 11 percent porosity as interpreted from a combination of wireline log and core data. Average field wide porosity for this reservoir is estimated at 14.5%. Deliverability is demonstrated by flow testing of Senecio-3.

It is predicted that the conventional gas bearing reservoirs extend throughout the greater Waitsia field structure including the undrilled sectors in the south and east. Contingent resource estimates have been made for these areas using the same reservoir assumptions but further appraisal drilling is required to determine reservoir deliverability and book these as reserves.

Development planning and economic modelling indicate that the development of these reserves and contingent resources is economic under AWE’s market and gas price assumptions. The preliminary fullfield development plan involves the drilling and completion of 20 vertical or deviated production wells, including the three wells drilled to date, with connection to a centralized gas processing facility. It is envisaged that export to domestic markets at a plateau rate of about 85 million standard cubic feet per day (MMscf/d) would utilize existing nearby gas pipelines. The composition of the gas (c.93 percent methane) indicates that only minimal processing will be required. Early production start-up will be sought subject to achieving the required regulatory approvals.

In addition, further contingent resources have been estimated for lesser quality gas bearing reservoir intervals in the Kingia and High Cliff Sandstone formations which have porosity in the range 7 to 11 percent. More data and work are required to determine whether some, or all, of these Waitsia field contingent resources intervals will be booked as reserves in the future.

The Senecio-3, Waitsia-1 and Waitsia-2 wells have been completed as production wells and will form part of a future field development.

The Joint Venture partners in L1/L2 are:


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