Transocean rig reaches Australian waters to embark on ‘critical’ gas search

ConocoPhillips Australia (COPA), a subsidiary of the U.S.-headquartered energy giant ConocoPhillips, is laying the groundwork to kick off seabed surveys this month ahead of exploration drilling activities for which a semi-submersible rig owned by Transocean, a Switzerland-based offshore drilling contractor, has arrived in the Otway Basin to find commercially viable natural gas reserves and keep fears of shortfalls at bay.

After COPA sought approval for an offshore drilling campaign off the coast of Victoria and Tasmania, the proposed Otway Exploration Drilling Program (OEDP) got the green light from the Australian regulator, the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA). This allows seabed surveys and drilling activities entailing up to six exploration wells to be conducted in VIC/P79 and T/49P offshore titles in Commonwealth waters, adjacent to existing natural gas developments in the Otway Basin.

ConocoPhillips, as the operator with an 80% stake in the offshore permits, booked AHTS vessels from Sea1 Offshore, formerly Siem Offshore, and Transocean’s Transocean Equinox semi-submersible drilling rig for work on the Otway project. The rig, hired on a two-well drilling contract signed as part of a 2025 exploration program for the project, has arrived in Australia.

The unit is slated to begin Phase 1 drilling in the third quarter of 2025, pending weather and any operational delays, according to ConocoPhillips’ partner, 3D Energi, a Melbourne-based oil and gas exploration player whose subsidiary, TDO, holds a 20% interest in both permits. Two firm exploration wells are to be drilled in 2025 as part of Phase 1.

This will be followed by up to four additional optional wells once Phase 2 starts between 2026-2028 across exploration permits VIC/P79 and T/49P. Currently, preparations are nearing completion for seabed surveys, which are scheduled to commence in the Commonwealth offshore permit area VIC/P79 in April 2025, ahead of exploration drilling.

For 3D Energi, the OEDP is a “critical” gas project for the future gas needs of southern Australia, given the rapidly declining production from Bass Strait and forecast shortfall risks under peak conditions. The company believes that this program, should it be successful, could place it as a key player in meeting Victoria’s and the broader East Coast’s future energy demands from 2028 and structural supply gaps from 2029.

Noel Newell, Executive Chairman of 3D Energi, commented: “The arrival of the drilling rig marks another step towards unlocking significant gas resources in the offshore Otway Basin through the Otway Exploration Drilling Program (OEDP). Operational sequencing with the consortium will see the Joint Venture commence its Phase 1  drilling campaign in 2025, with ConocoPhillips Australia (COPA) carrying up to US$65M in gross costs.

“The OEDP will play a vital role in addressing east coast gas shortages, targeting low-risk gas prospects with Direct  Hydrocarbon Indications (DHI’s), situated proximal to infrastructure. Amid tightening gas supply, the arrival of the Transocean Equinox reinforces the company’s role in meeting future energy demand and unlocking long-term growth opportunities. Potential discoveries in this campaign could underpin many years of gas exploration in the region, providing a long-term solution to the East Coast gas shortage.” 

Moreover, the seabed surveys are expected to take four weeks to complete, ocean conditions permitting. The final selection of well locations is yet to be confirmed pending the completion of subsurface 3D seismic interpretation studies across VIC/P79 and T/49P exploration permits. The Transocean Equinox semi-submersible drilling rig is on hire for a minimum 16-well drilling campaign with a consortium of four operators, including ConocoPhillips.

The environment plan (EP) for the OEDP gas project proposes the drilling of up to six exploration wells in water depths ranging from 53 to 200 meters across the VIC/P79 and T/49P exploration permits. 3D Energi underlines that preparations are ongoing toward obtaining well operations and safety approvals from NOPSEMA, which involves the submission and review of the well operations management plan (WOMP) and the safety case revision.

ConocoPhillips’ partner emphasized: “With declining production from the Bass Strait gas fields and an ongoing East Coast energy crisis, this program is increasingly critical for maintaining gas supply to Victoria and the broader region. The 2025 Gas Statement of Opportunities projects peak-day shortfall risks from 2028 and structural supply gaps from 2029 in southern  Australia.

“The exploration program focuses on low-risk gas prospects with Direct Hydrocarbon Indications (DHIs) in the offshore Otway Basin, an area with a strong track record of successful discoveries from similar prospects. Proximity to existing infrastructure and the East Coast gas market further enhances the commercial viability of potential finds.”