Petrel Sub-Basin South-West 3D Marine Seismic Survey
Santos Limited, propose to undertake a 3D seismic marine surveys (the ‘survey’) over petroleum permit areas WA-454-P, WA-545-P, WA-27-R and WA-40-R and surrounding waters in the Bonaparte Basin in Commonwealth waters off the Western Australia and Northern Territory coast. At its closest point, the survey Operational Area is located approximately 114 km from Kulumburu and approximately 169 km from Wyndham in WA.
The survey data is required to develop regional geologic models to inform the exploration and development strategy for several petroleum permits, and the potential location of future drilling of exploration and development wells.
Seismic acquisition will be via methods and procedures similar to other seismic surveys conducted in Australian waters. The seismic survey vessel will travel along a series of pre-determined lines towing cables (known as streamers or acoustic receivers) which contain microphones (known as hydrophones). As the survey vessel travels along the lines, sound waves will be directed down through the water and into the geology below the seabed. The sound that reflects back is measured by the hydrophones and is later processed to provide information about the structure and composition of geological formations below the seabed.
Santos intends to acquire the full survey between 1 December 2021 and 31 March 2022. However, should this not be achievable, then some or all of the survey may instead be acquired the following year, between 1 December 2022 and 31 March 2023. The timing of the survey is dependent upon vessel availability, weather conditions, stakeholder consultation feedback, the receipt of the required statutory approvals and the control measures within this EP.
The survey is planned to be acquired over three areas, Areas A, B and C, and is estimated to take up to 100 days to complete, with operations occurring on a 24-hour basis. An additional 5 days of contingency time within the operational area has been provided as part of the environmental assessment.
The survey Operational Area defines the area within which the seismic survey and support vessels will operate and is approximately 12,833 km2. Water depths across the Operational Area range from 40 meters (m) and 107 m (below mean sea level).
Each Survey Area is comprised of an Active Source Zone and a Full-fold Acquisition Area. The Full-fold Acquisition Area is the area within which the seismic source will be operated in full acquisition mode to achieve the geophysical objectives of the survey. This combined are for this zone is approximately 3,584 km2, with water depths ranging from approximately 60 m to 103 m. The Active Source Zone surrounds the Full-fold Acquisition Area and typically, this zone will be used to incrementally build the power of the seismic source from non-operation to full capacity, for soft starts. This zone is approximately 10,282 km2, with water depths ranging from approximately 45 m to 105 m.