AIM-listed and Singapore-headquartered oil and gas player Jadestone Energy has received a stamp of approval for its environmental plan (EP) from the country’s offshore regulator for wellhead removal activities at its oil field off the coast of Australia.

The National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) gave Jadestone the green light on April 22, 2026, to move forward with activities proposed in its submitted environment plan, entailing the removal of three wellheads: Montara-1, 2, and 3 within production licence AC/L7.

The company plans to remove the three wellheads from the Montara field, which lies approximately 690 kilometers (373 nautical miles) east of Darwin in a water depth of around 80 meters. The field was discovered in 1988 with the drilling of the exploration well Montara-1, and later appraised with the drilling of appraisal wells Montara-2 and Montara-3 in 1991 and 2002, respectively.

The wells were suspended with annual monitoring undertaken by a remotely operated vehicle (ROV). Both the primary and secondary barrier envelopes were verified in 2021, and the wells confirmed to be plugged and abandoned as per the NOPSEMA accepted well operations management plan (WOMP). A final abandonment report was submitted to the regulator for these wells in September 2021.

The accepted EP, which provides for the removal of Montara-1, 2, and 3 wellheads, includes remote operated vehicle (ROV) activities such as ‘as found’ and ‘as left’ surveys, marine growth removal, and wellhead area preparation.

Jadestone has listed multiple methodologies for the wellhead removal activity to allow for vessels and tools of opportunity over the validity of the EP: abrasive water jet cutting (AWJC), external cutting using diamond wire saw (DWS), or equivalent, and mechanical internal cutting.

While the duration of the activity at each wellhead is expected to be approximately 2 days, an allowance of approximately 14 days has been provided, including mobilization, seabed surveys, wellhead removal, and demobilization, to allow for mobilization and demobilization of the vessel and unforeseen delays due to weather or equipment.

One vessel is required to complete this activity with the capacity to recover the subsea infrastructure to the deck. The dismantling and disposal of the wellheads is anticipated to be completed within 12 months of arrival at the receiving port and waste management facility.

The wellhead composition is predominantly mild steel, and it is anticipated that most of it will be recycled or repurposed. The EP underlines that the wellhead removal will be subject to the availability of a suitable vessel, and whenever feasible, will be a vessel of opportunity mobilizing to the Montara field for other activities.

As a result, the exact timing of the wellhead removal is unknown. However, removal activities may be undertaken at any time during the life of the EP, which is five years from acceptance.

The Jadestone-operated and owned Montara project, encompassing three separate fields – Montara, Skua, and Swift/Swallow – is located in the Timor Sea offshore Australia, approximately 690 kilometres west of Darwin.

The oil from the subsea wells is piped via subsea flowlines to an unmanned wellhead platform and then to the FPSO Montara Venture, which acts as a hub for the Montara fields.

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