Otway Basin Prospects Updated: 9.2 Tcf Gas Resource and Six Wells Planned

A Significant Upgrade in Otway Basin Prospects

3D Energi Limited (ASX, TDO) has announced a major update to its offshore gas exploration portfolio in the Otway Basin, offshore Victoria and Tasmania. The company’s latest evaluation, leveraging nearly 4,000 square kilometres of advanced 3D seismic data, has identified 51 prospects with an aggregated mean prospective resource of 9.2 trillion cubic feet (Tcf) of gross recoverable gas. This represents one of the largest prospective gas inventories in the region and underscores the basin’s potential to contribute meaningfully to Australia’s East Coast gas supply.

The update comes ahead of the Otway Exploration Drilling Program (OEDP), scheduled to commence in the third quarter of 2025. The program will see up to six exploration wells drilled across two key permits, VIC/P79 and T/49P, where 3D Energi holds a 20% interest. The goal is to convert these prospective resources into commercial reserves that can support the region’s growing energy needs.

Charlemont Cluster, A Near-Term Game-Changer

Among the portfolio, the Charlemont Cluster stands out as a high-graded, low-risk target. It comprises seven amplitude-supported prospects with a combined mean prospective resource of approximately 1 Tcf gross. This cluster is strategically positioned near existing infrastructure, which could facilitate quicker and more cost-effective development. If successful, the Charlemont Cluster alone could supply up to 1,070 petajoules (PJ) of gas, roughly equivalent to six years of Victoria’s total gas consumption.

Enhanced seismic reprocessing in 2024 has significantly improved the imaging of direct hydrocarbon indicators (DHIs) within this cluster, reducing exploration uncertainty. The upcoming drilling program includes up to four wells targeting Charlemont prospects, with three potential Phase 1 well locations already identified.

Broader Portfolio and Strategic Exploration Approach

Beyond Charlemont, 3D Energi’s portfolio includes the Flanagan and Regia Clusters, which offer material upside and expansion pathways. The Flanagan Cluster features a 1.5 Tcf gross mean prospect, potentially the largest in the basin, while the Regia Cluster remains a frontier area with planned new 3D seismic acquisition to mature future targets.

Further south, the Whistler Point, British Admiral, and Seal Rocks Clusters represent higher-risk, frontier exploration opportunities. Although these prospects are more distant from infrastructure and carry greater uncertainty, they provide strategic balance and the potential for significant long-term resource additions.

Addressing Victoria’s Looming Gas Shortfall

The timing of this resource update is critical. The Australian Energy Market Operator forecasts peak-day gas shortfalls in Victoria and southern states starting as early as 2025, with structural supply gaps expected from 2029 onwards. 3D Energi’s exploration efforts align with the urgent need for new gas supplies to maintain energy reliability and security on the East Coast.

Executive Chairman Noel Newell emphasised the company’s focused strategy balancing low-risk, infrastructure-led plays with high-impact frontier opportunities. The upcoming drilling campaign aims to deliver near-term results while building a foundation for long-term value creation.

Looking Ahead

3D Energi’s detailed seismic work and updated resource estimates position it well for the 2025 drilling program. Success in converting these prospects into commercial discoveries could significantly influence the East Coast gas market and Victoria’s energy landscape. However, the path to development remains contingent on multiple factors including technical success, regulatory approvals, and market conditions.