Location of WA-499-P permit; Source: Santos

Offshore regulator clears Santos’ plan for drilling location survey

National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) has approved Santos’ plan for a geophysical survey in preparation for the proposed Yoorn-1 well drilling offshore Australia.

Location of WA-499-P permit; Source: Santos
Location of Yoorn-1 well; Source: Santos
Location of Yoorn-1 well; Source: Santos

NOPSEMA said that the environmental plan for the Yoorn-1 survey, located in permit area WA-499-P, was submitted in March 2020.

According to the offshore regulator, the survey plan was accepted on Wednesday, 3 June 2020.

Santos stated in the proposed plan that a vessel-based site survey would be done as part of the drilling preparatory work. The survey will involve 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 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 and side-scan sonar data to define the bathymetry and seafloor morphology.

Namely, it would identify any hazards that may impact the location of a MODU through sub-bottom profiling. The company said that it would also grab sampling or drop cores for ground-truthing the surficial geophysics 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 40-50 metres. The activity will take place in 2021-2022.

Allowing for potential downtime, 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.