Singapore-headquartered Jadestone Energy has withdrawn an environment plan (EP) for wellhead abandonment operations at a field, located offshore Western Australia.
Australian offshore regulator, the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA), recently revealed that Jadestone Energy withdrew the EP for the Montara field, entailing the permanent abandonment of four wellheads in situ, which was lodged with the regulator on 22 October 2021. No reason was provided for this withdrawal.
Prior to the withdrawal, Jadestone Energy proposed to permanently abandon Montara‐1, Montara‐2, Montara‐3 and Skua‐1 within the Montara field, which 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.
Skua-1 is located within production licence AC/L8 and Montara-1, 2 and 3 are in AC/L7 within the Montara field which lies approximately 690 km – 373 nautical miles – east of Darwin in a water depth of approximately 80 metres in Commonwealth waters of the Timor Sea.
Within the EP, the company explained that both the primary and secondary barrier envelopes were verified in 2021, and the Montara-1, 2 and 3 wells were confirmed to be plugged and abandoned as per the NOPSEMA’s accepted Well Operations Management Plan (WOMP).
On the other hand, Skua‐1 was accepted as plugged and abandoned under the Petroleum Submerged Lands Act (PLSA) by the Department of Mines – the department ceased in 1992 – in 1974, thus, no WOMP was required for this well, according to Jadestone.
Furthermore, the withdrawn EP proposed to leave the wellheads in situ in perpetuity, elaborating that no further operations, environmental monitoring, inspections or maintenance were required.
The Jadestone operated and owned Montara project includes three separate fields – Montara , Skua and Swift/Swallow – which produce through a centralised FPSO Montara Venture .
When it comes to the most recent developments at this project, it is worth noting that Jadestone disclosed its decision to temporarily shut-in production from Montara a few days ago. This is expected to help the firm reorganise offshore manpower on the FPSO, enabling focus on maintenance and inspection crews.
This decision comes after Jadestone restarted production at the field following a small leak of oil in June from the 2C crude oil tank on the FPSO Montara Venture. Interim repairs of the leak point were undertaken prior to the restart of production and a permanent repair of the 2C tank was planned to start shortly afterwards.