Junior explorer Vintage Energy (ASX: VEN) has posted a strong quarter to 30 June with a 100% success rate in drilling at four wells within the onshore Cooper-Eromanga Basin between Queensland and South Australia.
Work at the Vali-2 well appraised the Patchawarra and Tirrawarra formation targets, while wireline logging confirmed gas in Patchawarra and the Tirrawarra Sandstone and a new gas pool at the Toolachee formation.
The well was drilled to total depth of 3,240m and cased for production.
Vali-2 has an interpreted 24m of stacked net gas pay in Toolachee (8% porosity cut-off), distributed between three thick sandstone packages and five thinner ones.
A gas gradient was established through MDT (modular formation dynamics tester) pressure measurements and a gas sample recovered.
Analysis of the sample indicated Toolachee gas has a higher percentage of hydrocarbons at 82% (75% methane, 4% ethane, 3% other hydrocarbons) and 18% inert gases, compared to Patchawarra gas in the Vali-1 ST1 well, which has around 76% hydrocarbons and 24% inert gases.
Wireline logging and MDT results indicate the Toolachee reservoir could flow without the need for fracture stimulation.
Oil and gas shows
Vali-3 also appraised Patchawarra gas to a total depth of 3,186m, with gas shows observed in the lower Nappamerri Group, Toolachee, and Epsilon formations and Tirrawarra Sandstone, and oil shows in the Jurassic and Triassic sediments and at Toolachee.
Samples from Nappamerri and Toolachee are being analysed to determine whether gas pay can be interpreted at any of the sands in these zones.
Oil shows were also observed through the late Cretaceous, Jurassic and Triassic sediments, as well as the uppermost part of Toolachee.
Similar shows were encountered in the Vali-1 ST1 and Vali-2 wells and are believed to be a “major positive” in terms of oil potential, with more than 12 oil leads identified within the ATP 2021 joint venture.
Vali-3 has been cased for future production, with wireline logging confirming the interpreted gas pay within Patchawarra is consistent with pre-drill expectations.
It is the third casing at the Vali field for ATP 2021, which comprises Vintage (50% and operatorship), Metgasco (ASX: MEL) (25%) and Bridgeport (Cooper Basin) (25%).
The partners are now progressing plans for production from Cooper Basin, after the Australian Competition and Consumer Commission granted final approval during the quarter for the joint marketing of gas from the Vali field.
Odin-1 gas pay
In May, the Odin-1 exploration well, also in the Cooper Basin, reached total depth of 3,140m with extensive gas shows encountered in sandstones through the primary Toolachee target and Patchawarra, as well as a basal sand in the secondary Epsilon target.
These shows were confirmed as gas pay via the wireline evaluation program and gas samples were recovered from Toolachee and Epsilon.
It is estimated that 172.5m of net gas pay exists within various sections of the well.
The well has been cased for future production, with a likely option being the connection of the Odin field into the Vali production network.
In Victoria’s onshore Otway Basin, production testing of the Nangwarry-1 well was completed during the quarter with perforations across targeted zones in the Top Pretty Hill formation.
The well produced strongly and delivered a “higher than anticipated” raw gas rate of approximately 10.8 million standard cubic feet per day.
Post-quarter, an independent resource estimate confirmed a sizeable carbon dioxide sales gas resource for the Nangwarry field of 25.9 billion cubic feet (12.9Bcf net).
The field could potentially provide a stable and reliable source of food grade carbon dioxide, which is currently in high demand since the depletion of onshore Otway Basin well Caroline-1 in 2017.
The main industrial uses for food grade carbon dioxide include the carbonation of soft drinks, fruit juices and beer; cold storage and refrigeration; medical devices; production of paints and varnishes; and the manufacture of foam rubber.
Commercial development of the Nangwarry field is a joint venture between Vintage (50% and marketing agent) and Otway Energy Pty Ltd (50% and operator).
Vintage has a 30% stake in the Cervantes prospect within WA’s Perth Basin, with partners Metgasco (30%) and RCMA Australia (40%).
The prospect is a high-side fault trap of multiple Permian sandstone reservoir targets, known to be prolific producers in the Perth Basin.
Studies have shown the prospect to have a 28% chance of success and a high chance of development due to its close proximity to the producing Jingemia oil field and processing facility.
WA’s environmental regulator has indicated its support for the drilling of Cervantes, allowing the joint venture partners to construct a well pad in preparation for a spud date later this year subject to rig availability.
During the quarter, Vintage terminated a farm-in arrangement with Firetail Energy Services Pty Ltd when the private company went into administration.
The deal over EP126 in the Northern Territory would have seen Vintage earn 10% equity.
It is now pursuing interest from other parties in a bid to attract a new joint venture partner.