The Vali gas field is an onshore development located in the ATP 2021 permit in Queensland, Australia.
The permit is owned by a joint venture (JV) between Vintage Energy (50%, operator), Metgasco (25%) and Bridgeport (Cooper Basin) (25%).
Discovered by the JV in 2020, the gas field will be connected to the South Australian Cooper Basin gas gathering infrastructure to act as a source of gas for eastern Australia. The field will supply between nine and 16 petajoules (PJ) of gas to AGL, Australia’s leading energy company.
Commissioning for the field’s first well began in February 2023, while the other two wells are expected to be commissioned by March 2023.
The ATP 2021 permit is located on the Queensland side of the Cooper/Eromanga Basins and covers an area of approximately 370km².
The permit lies adjacent to numerous gas and oil fields, including associated pipelines and facilities.
Geology and reserves
The Permo-Carboniferous to Triassic Cooper Basin is composed of up to 2,500m of sediment, which consists of interbedded sandstones, shales and coals. It is overlain by the Early Jurassic to Late Cretaceous Eromanga basin, which has sediment up to 3,000m in thickness and consists of sandstones, siltstones and shales.
The target zones comprise Permian gas and Jurassic oil reservoirs.
The Vali gas field is estimated to hold proven and probable reserves of 46 billion standard cubic feet (Bscf).
Vali gas field appraisal
The Vali-1 ST1 well was drilled between December 2019 and January 2020. It reached a depth of 3,217m and discovered gas in the primary Patchawarra formation target. The well identified up to 80m of interpreted log net gas pay over a gross 312m interval.
Potential gas pay was also calculated in the secondary target, the Permian-aged Toolachee formation and Tirrawarra Sandstone, and in the Triassic-aged Nappamerri Group. In addition to recovering gas from the Patchawarra Formation through MDT sampling, gas was also recovered from the Nappamerri Formation.
The Vali-2 and Vali-3 wells were drilled to appraise the Patchawarra gas accumulation between April and July 2021. Vali-2 also assessed the potential for gas in the Toolachee formation.
The Vali-2 well was drilled to a depth of 3,240m to intersect the Toolachee and Patchawarra formations. The well encountered 24m of net gas pay in the Toolachee formation and 117m of net gas pay in the Patchawarra formation.
The Vali-3 well was drilled to a depth of 3,186m to intersect the Patchawarra formation. It encountered gas shows in the lower Nappamerri Group, Toolachee, Epsilon and Patchawarra formations, as well as the Tirrawarra Sandstone.
Field development details
The Vali gas field will be developed through three wells, namely Vali-1, Vali-2 and Vali-3. It will also involve the installation of metering facilities at the Vali facility. The works include the separation and installation of flowlines connecting the three completed wells to the metering facility. Twin export gas pipelines that tie into the Moomba gas gathering network located at the Beckler gas field will also be installed.
The completed export flowlines were successfully pressure tested in December 2022. The gas wells will be connected and brought online progressively, starting with Vali-1 and followed by Vali-3 and Vali-2.
The control of the Vali-1 facilities was handed over to Upstream Production Solutions (UPS) in February 2023. The Vali-2 and Vali-3 sites are undergoing construction and installation, with mechanical handover and commissioning expected by early March 2023.
An integrated service provider based in Australia, UPS was awarded the commissioning, operation and maintenance contract for the Vali-1 well infrastructure.
The front-end engineering design (FEED) for Vali-1 ST1 connection was awarded to GPA Engineering, an engineering, project management and construction management services provider.