ASX-listed Beach Energy, as the operator of retention leases T/RL2, T/RL4 and T/RL5 in the Commonwealth waters of Bass Strait, is proposing to undertake the Prion 3D marine seismic survey over these leases.
The purpose of the Prion 3D survey is to acquire geophysical data to gain deeper knowledge of the subsurface geology in order to identify commercially viable gas reservoirs for future development.
The proposed Prion survey comprises two areas: Acquisition area covering 880 square kilometres and Operational area of 2,272 square kilometres.
Water depths in the survey area range from 50 metres to 80 metres.
At its nearest points, the survey area is located 75 kilometres east of King Island and 57 kilometres from Stanley in Tasmania.
The Prion 3D survey is scheduled to commence between July 2021 and June 2022, but may not commence until June 2023.
This environmental plan is valid for a survey start date of any time up until June 2023.
The survey should take up to 40 days, though the vessel may be present on location for longer than this depending on factors such as sea state conditions, whale-instigated shutdowns and technical issues.
Data acquisition details
Specifically, the survey vessel will acquire the seismic data by towing three acoustic source sub-arrays operating alternatively, one discharging as the others recompress.
The lateral distance between each of the sources will be 100 metres. The source volume will be a maximum of 2,495 cubic inches with an operating pressure of 2,000 pounds per square inch. There will be 10 to 12 hydrophone streamer cables approximately 8,000 metres long towed behind the survey vessel. The vessel will sail back and forth across the acquisition area along 76 sail lines (nominally) that will be spaced 300 metres apart.