Australia's National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) has approved Santos Offshore's plan to conduct a 3D seismic survey in the Bonaparte Basin.

Santos is proposing to undertake a 3D seismic marine 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 Western Australia and Northern Territory coast.

At its closest point, the survey operational area is located approximately 114 kilometers from Kulumburu and approximately 169 kilometers from Wyndham in Western Australia.

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.

Revision 0 and Revision 1 of the EP sought acceptance from NOPSEMA for a survey area that included three Full-fold Acquisition Areas (Areas A, B and C). However, for Revision 2 of the EP, Santos has opted to remove Full-fold Acquisition Area C, thus reducing the survey operational area and active source zone commensurate.

The decision to remove Full-fold Acquisition Area C was made as part of Santos' ongoing efforts to continue to reduce impacts and risks to ALARP and in response to concerns raised by stakeholders. Acquisition of Full-fold Acquisition Area C is no longer a priority for the survey and Santos considers it practicable to reduce the total operational area and to reduce potential impacts from the survey.

The operational area has been reduced by 3,187 km2 (25%). Revision 3 of the EP includes additional adaptive management measures for marine fauna and clarification of ESD principles in response to an opportunity to modify and resubmit the EP for Acceptance to NOPSEMA.

The survey is planned to be acquired over two Full-fold Acquisition Areas, Area A and Area B, and are separate from one another, but sail lines may continue within the defined active source zone, with the seismic source operating between the two Full-fold Acquisition Areas during line run-ins and run-outs.

Due to this approach and the resultant improvement in operational efficiency the total survey timing has been reduced from 100 days to 60 days, with operations occurring on a 24-hour basis.

An additional five days of contingency time within the operational area has been provided as part of the environmental assessment.