Walyering Gas Field is a conventional gas discovery located within the Exploration Permit (EP) 447, in the onshore Perth Basin, Western Australia.
Strike Energy operates EP447 with 55% interest, while Talon Energy owns the remaining 45% non-operated participating interest.
According to an independent estimate by RISC Advisory, Walyering’ contains 2P gas Reserves of 54 peta joule (PJ) and 0.55 mmbbls condensate.
The EP447 joint venture (JV) took the final investment decision (FID) and approved the development of the gas field in August 2022.
The project’s commissioning gas is expected to enter the upstream facility by the end of 2022, with the first sales targeted in the first quarter of 2023.
Once commissioned, the project is expected to have an operational life of ten years.
Location and Reserves
The Walyering Conventional Gas Development is situated around 6.5km northwest of Cataby settlement in Western Australia.
The proposed development envelope includes 91.41 hectares (ha) with an area of disturbance of 15.31 ha.
The two companies took the FID following the completion of an independent certification of Walyering reserves by RISC Advisory.
Walyering hosts a gross 2P Reserve of 54.2PJ of gas and 0.55MMbbl of condensate, a 2C Contingent Resource of 31.9PJ of gas and 0.31MMbbl of condensate. A 2U Prospective Resource of 15.9PJ of gas and 0.16MMbbl of condensate were also assigned to the project.
The gas field is expected to produce between 150 barrels per day (bbls/d) and 300 bbls/d of condensate.
The gas condensate from the Walyering gas reserves has been laboratory-measured to be a premium product with a profile between jet fuel and gasoline.
Exploration drilling at Walyering was first conducted in 1971.
The Walyering 1 and Walyering 2 wells were drilled in 1971 and Walyering 3 well was drilled in 1972. It was stated that the three wells did not test a valid gas trap.
In 2001, the Walyering 4 well was drilled with the discovery of a non-commercial gas find.
In 2019, Strike Energy acquired three-dimensional seismic imagery over the Walyering structure in EP 447 R1 that led to improved structural mapping.
In November 2021, Walyering 5 exploration well was drilled by Strike Energy with well-testing activities commencing in March 2022.
Walyering 5 intersected several gas reservoirs, including the early Jurassic Age (Pleinsbachian and Toarcian) Cattamarra Coal Measures (A, B, C, and D Sand).
Another gas discovery was made with the Walyering 6 well in May 2022. It reached a depth of 3,551m intersecting a discovery in the Cadda Formation and 21 of pay in Cattamarra Sand.
Strike Energy and Talon started working for FID following the successful drilling of the Walyering-5 and Walyering-6 appraisal wells.
Both the wells were flow tested and the data will be used to design the gas processing and condensate storage facility within the site.
The project will include the development of a production facility with a maximum export capacity of around 30 Terajoules (TJ) per day/annualised.
It will also involve installation of a gathering system including well infrastructure and flow lines to transfer extracted gas from the existing Walyering 5 and Walyering 6 production wells to the production facility.
The production facility will transport gas to a metering station and tie-in point connecting the Parmelia Gas Pipeline from where it will be exported for use in the domestic market.
An ongoing review is also exploring the feasibility of connecting the gas production to the Dampier to Bunbury Natural Gas Pipeline (DBNGP) in near future.
The production facility will include a chemical injection skid, slug-catcher, two 110,000 litre condensate storage tanks, and pumps for storage and stabilisation, two 55,000 litre water storage tanks and pumps, truck offtake facilities, and other support utilities.
A solar array of 108 panels and accompanying battery storage will provide power to the upstream facility.
The project development will cost around A$14.4m. This includes completing the Walyering 5 and 6 wells, the on-site facility designed to process 33 TJ/d of gas and separate around 150 – 300 bbls/d of condensate that will be diverted to 1,400 bbls onsite storage and other related works.
Strike has received A$10m from Macquarie Bank Limited to fund its A$7.9m share of the development costs.
Field operations will be controlled from Strike Energy’s remote operations centre in West Perth
Contractors involved and agreements
In May 2022, the JV awarded the front-end engineering and design (FEED) contract for Walyering facilities and related infrastructure to Momentum Engineering.
Strike Energy has signed a long-term gas supply agreement with Perth Energy (AGL Limited). The company will supply a total of 14.6 PJ of gas on a firm basis to Perth Energy for a period of five years starting 2024.