Santos WA proposes to conduct exploration drilling in permit area WA-499-P, located in Commonwealth waters. As part of the drilling preparatory work, a vessel-based site survey will be undertaken involving geophysical survey techniques to assess the shallow seabed soils suitability to provide a safe foundation for a jack-up mobile offshore drilling unit (MODU). The survey activity (‘the activity’) which is the subject of this environment plan (EP) will involve surveying the planned drilling location and tie-in lines extending from the proposed drilling location to existing data points in the nearby area. The survey tie-in lines intersect both Commonwealth and state waters.
The survey will be undertaken using multi-beam echo sounding (MBES) and side-scan sonar (SSS) data to define the bathymetry / seafloor morphology. Identification of any hazards that may impact the location of a MODU through sub-bottom profiling (SBP) and grab sampling or drop cores for ground-truthing the surficial geophysics and to support MODU spud-can penetration assessments.
The operational area overlaps permit areas WA-499-P in Commonwealth waters and TL/5, TP/8 and TP/27 in State waters. Water depth in the operational area ranges from approximately 40 m to 50 m. The activity will take place in 2020-2021. Allowing for potential down time, for example due to weather or vessel operability issues, the activity may extend to up to 10 days. Activities will be undertaken up to 24 hours per day.