Red Sky Energy Intersects Gas Pay at Yarrow 4 in Cooper Basin Development
Key Takeaways
- Yarrow 4 reached total depth of 2,908 metres on 6 September 2026, confirming gas pay in the Tirrawarra Sandstone — the well's primary target — with 5.2 metres of LDG net pay and reservoir pressure of approximately 3,335 psi.
- Santos, as 80% operator, has recommended the well be cased and suspended as a future producer pending fracture stimulation and completion, with Red Sky's 20% interest preserved in the process.
- Commercial deliverability cannot be confirmed until the well is fracture stimulated and tested — no flow rates have been established from Yarrow 4 at this stage.
- Rig 184 moves directly to drill Yarrow 5 on the same dual-well pad immediately after casing operations at Yarrow 4 are complete, keeping the Innamincka Dome program on sequence.
- A completed Yarrow 4 would tie into the existing Santos gas-gathering and pipeline network already serving Yarrow 1 and Yarrow 3, reducing infrastructure capital required to reach first production.
Yarrow 4 strikes gas pay at 2,908 metres, earmarked as future producer
Red Sky Energy (ASX: ROG) has confirmed that its Yarrow 4 development well reached total depth of 2,908 metres on 6 September 2026, intersecting gas pay in the Tirrawarra Sandstone, the well’s primary target. Santos, as operator with an 80% interest, has recommended the well be cased and suspended for future hydraulic stimulation and completion, a recommendation Red Sky — holding a 20% working interest — supports.
No flow rates have been established, and the source is explicit that commercial deliverability cannot be determined until the well is fracture stimulated, completed, and tested.
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Q1 FY27 drilling results at a glance
The tables below present the preliminary petrophysical results and well data from the ASX announcement dated 8 September 2026.
| Formation | Interval (m MD) | Gross sand (m) | LDG pay (m) | Avg porosity | Avg water saturation |
|---|---|---|---|---|---|
| Patchawarra Formation | 2,818.9 – 2,833.0 | 1.7 | 0.2 | 9.2% | 19.8% |
| Tirrawarra Sandstone | 2,836.0 – 2,858.5 | 11.4 | 5.2 | 7.8% | 40.9% |
| Total | 5.4 |
LDG pay is calculated using standard Cooper Basin low deliverability gas cut-offs: effective porosity greater than 4% and water saturation less than 70%. Applying conventional gas net pay cut-offs (effective porosity greater than 8%, water saturation less than 50%) reduces net pay in the Tirrawarra Sandstone to 0.9 metres. A further 1.1 metres of LDG pay was interpreted in the Merrimelia Formation but does not form part of the planned completion. Results are preliminary, derived from logging while drilling data, and remain subject to revision.
| Item | Detail |
|---|---|
| Well | Yarrow 4 (development well) |
| Permit | PRL 17, Innamincka Dome, Cooper Basin, South Australia |
| Surface location | Latitude 27.345 S, Longitude 140.794 E (GDA2020) |
| Interests | Santos (ASX: STO) 80% and operator; Red Sky Energy 20% |
| Rig | Rig 184 |
| Spud date | 31 August 2026 |
| Total depth reached (date) | 6 September 2026 |
| Total depth | 2,908 metres measured depth |
| Primary targets | Tirrawarra Sandstone and Patchawarra Formation |
| Formations penetrated | Toolachee Formation, Patchawarra Formation, Tirrawarra Sandstone, Merrimelia Formation, pre-Permian |
| Data acquired | Logging while drilling triple combo suite (gamma ray, density, neutron, resistivity) and an LWD-conveyed downhole formation pressure survey (12 pre-test stations) run by SLB |
| Interpretation | Preliminary petrophysical evaluation of open LWD logs prepared by Santos as operator |
What low deliverability gas means for Cooper Basin investors
Low deliverability gas (LDG) pay is gas-saturated rock that, due to its permeability characteristics, requires hydraulic fracture stimulation — commonly called “fracking” — to flow at commercially meaningful rates. In the Cooper Basin, this is entirely standard practice, not a red flag.
The distinction matters: LDG is not a failure to find gas. It is a description of how that gas will be recovered. The Cooper Basin has produced gas from LDG reservoirs for decades, and fracture stimulation is the routine method used to unlock flow rates from tight sandstone formations like the Tirrawarra.
The reservoir pressure reading of approximately 3,335 psi in the Tirrawarra Sandstone is a meaningful data point. Pressure at that level indicates a live, pressured gas system, suggesting the gas is present and retained in the reservoir. It is not a measure of flow rate, but it does confirm the reservoir is active.
“Cased and suspended” is equally routine. The well is not abandoned. Casing the well means running steel pipe into the borehole to preserve its integrity, and suspending it means sealing it until a workover rig returns for fracture stimulation and completion. The well is being preserved as a future producer.
For Red Sky investors, existing infrastructure at the Innamincka Dome matters here. Yarrow 1 and Yarrow 3 are currently producing gas into Santos’s established gas-gathering, pipeline, and processing network, which connects directly to the Moomba facility. A completed Yarrow 4 would tie into that same network, reducing the time and capital required to move from completion to first production.
Andrew Knox on the path to production
Andrew Knox, Managing Director, Red Sky Energy
“Yarrow 4 has intersected gas pay in the Tirrawarra Sandstone and will be cased and suspended as a future producer. The next step is to bring in a workover rig to stimulate and complete the well, while Rig 184 moves across the pad to drill Yarrow 5. This is the outcome we were working towards in this phase of the Yarrow development.”
The Managing Director’s commentary confirms the result sits within the company’s planned development sequence for the Yarrow program.
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What comes next for Red Sky’s Innamincka Dome program
The following steps have been outlined in the announcement:
- Production casing to be run at Yarrow 4 following retrieval of the drilling assembly.
- Rig 184 to move across the dual-well pad to drill Yarrow 5 immediately following completion of casing operations at Yarrow 4.
- A workover rig to return to Yarrow 4 for fracture stimulation and completion, with timing subject to workover rig availability and scheduling — no fixed date has been indicated.
- Civil works at the Willowie 2 appraisal well in PRL 18 are scheduled to commence in early September 2026, with spud estimated for late October 2026.
Red Sky holds a 20% working interest across six PRLs (14, 17, 18, 180, 181, and 182) within the Santos-operated Innamincka Dome Joint Venture. With Yarrow 4 preserved for completion and Yarrow 5 drilling to follow, the company’s Innamincka Dome program continues to advance through a sequenced, pad-based development approach consistent with its stated operational plan.
Red Sky’s Killanoola drilling programme was advancing concurrently across a separate permit in August 2026, reflecting the company’s broader multi-permit activity schedule beyond the Innamincka Dome joint venture.
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