Amplitude Energy (ASX:AEL): The 2nd straight drilling failure sent shares crashing!

Amplitude Energy (ASX: AEL) crashed over 40% this morning after a second consecutive drilling failure on Wednesday, confirming that its Isabella prospect in the offshore Otway Basin will not be commercially developed after flow testing revealed the reservoir cannot sustain production at viable rates. The plunge erased roughly A$500m in shareholder value in roughly an hour.

The result leaves the company’s East Coast Supply Project (its primary growth vehicle) without a confirmed new gas well, and compresses the entire ECSP thesis onto two wells yet to be drilled. This is the unambiguous consequence of exploration risk materialising twice in succession.

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Recap of Amplitude Energy (ASX:AEL)

Amplitude Energy (formerly Cooper Energy until 2024) is an Australian domestic gas producer with its primary operations concentrated in southeast Australia. The company owns and operates offshore gas fields in the Otway and Gippsland Basins in Commonwealth waters off Victoria, processing gas through the Athena Gas Plant and Patricia Baleen facilities onshore.

Its producing assets include the Casino, Henry, and Netherby gas fields in the Otway Basin and the Sole gas field in the Gippsland Basin, which together supply gas under long-term contracts to industrial and energy customers on the east coast. Amplitude also holds a non-operated interest in oil production in the Cooper Basin. In FY25, the company recorded trailing twelve-month revenue of approximately A$275m with underlying profitability still narrow. The company is an S&P/ASX 300 constituent.

Overview of the ECSP

The most significant item on Amplitude’s strategic agenda is the East Coast Supply Project (ECSP). The ECSP is a multi-well offshore drilling campaign in the Otway Basin targeting up to 90 terajoules per day of new gas supply, which the company estimates could supply around 600,000 Victorian homes for a decade. The ECSP is a 50/50 joint venture with O.G. Energy, with Amplitude as operator.

The programme involves four wells: the Elanora-1 exploration well, the Isabella sidetrack from that same wellbore, and two further wells targeting the Juliet prospect and the Annie discovery. First gas had been targeted for 2028. Capital expenditure guidance for FY26 was A$125-150m, the majority of which is ECSP-related.

The Isabella Result: Why It Is Not Commercial

To understand why Isabella has been abandoned, it helps to understand what flow testing actually measures. When a gas well is drilled and reaches a reservoir, the initial data, specifically the logs, pressure readings and core samples) can indicate that gas is present. That is what the early Isabella results in early March showed: gas-bearing sands in the primary Waarre C reservoir, low CO2 levels of around 5%, and what appeared to be strong reservoir performance. The market responded positively to those preliminary findings, and the company moved to the next step: a full flow test.

A flow test involves allowing gas to actually flow to surface from the reservoir, at controlled rates, while carefully monitoring the reservoir pressure. The critical question is not just whether gas comes out, it is whether the pressure holds up as it does. A commercially viable gas reservoir needs to maintain adequate pressure over a sustained period, because that pressure is what drives production.

If pressure falls rapidly during a test, it indicates the reservoir either lacks sufficient volume of gas, is poorly connected internally (meaning gas cannot flow freely through the rock from all parts of the field to the wellbore), or both. In Isabella’s case, pressure depletion during testing was too severe and too rapid to support a development decision. Put plainly: the reservoir ran out of pressure too quickly to make commercial extraction viable.

Amplitude’s CEO Jane Norman acknowledged the complexity that ultimately undid the prospect, noting that Isabella’s scale as a target corresponded with reservoir complexity. In plain English, this means the structural or geological features that made it appear large also made its internal connectivity difficult to predict. The well will now be plugged and abandoned, a process expected to take a few days. The drilling and well operations cost has been shared 50/50 with O.G. Energy, and management has confirmed the overall ECSP programme remains within its stated budget.

The Investor Reaction Was Not Good

The share price reaction was severe and rational in proportion. Amplitude closed Tuesday at A$2.67. By early Wednesday trade the stock had fallen to approximately A$1.55, a plunge of around 42%, and its lowest level in several years. The scale of the sell-off reflects not just the Isabella result in isolation but its context: this is the second failed well in the ECSP sequence. Elanora-1, drilled in January 2026 and targeting the Waarre A reservoir, was found to be water-bearing rather than gas-bearing and triggered a 20% fall at the time. Isabella was the recovery shot, the sidetrack that was meant to salvage exploration value from the same campaign. It has not delivered.

Investors are also repricing the Final Investment Decision (FID) timeline. Amplitude has confirmed that an FID on the ECSP development phase will now be deferred until after the Juliet and Annie wells are drilled in the second half of 2026. That pushes the decision point at minimum six to nine months further out, adds execution uncertainty, and means two more binary drilling outcomes must be navigated before the company can commit capital to the development phase. The market is correctly registering that the ECSP is now a narrower thesis built on fewer remaining chances.

So, What Happens Next?

The immediate path is operational: Isabella will be plugged and abandoned, and the rig (the Transocean Equinox) will prepare for the next well in the programme. Amplitude holds two additional rig slots, targeting the Juliet prospect and the Annie-2 development well. Juliet is a separate Otway Basin exploration prospect with what management describes as simpler geology than Isabella. Annie is a previously discovered gas field in VIC/L24, meaning it has an existing geological definition rather than being a greenfield exploration target, a structural distinction that may carry some weight for investors looking for differentiation from the Elanora and Isabella outcomes.

The first gas target of 2028 is technically still achievable if either or both of the remaining wells succeed and development can proceed on an accelerated timeline. Whether that timeline remains realistic will depend on the pace of drilling; after all, the next well is not expected until H2 2026.

Even then, it will depend on whether a positive result from Juliet or Annie is sufficient to trigger an FID without further appraisal work. The company’s balance sheet and cash position have not changed materially with this announcement, and the existing producing assets continue to generate operating cashflows. The ECSP is a growth project, not an existential one. But it was the core reason the market had assigned Amplitude a growth premium, and that premium has now been substantially removed.