NOPSEMA approves Santos’ WA-437-P geotechnical and geophysical survey

Santos WA Northwest has received approval from Australia’s NOPSEMA for a geotechnical and geophysical survey within Permit WA-437-P, located around 145 km from the town of Port Hedland.

The site survey is required to support pre-engineering studies for any future development and aims to aid in the understanding of the local geology and identify any potential subsea hazards.

The geophysical component of the survey is required to obtain detailed bathymetry measurements and detect hazards on or below the seabed.

Geophysical data collection will consist of single beam echo sounder (SBES); multi beam echo sounder (MBES); side scan sonar (SSS); and sub-bottom profiling (SBP).

The geotechnical survey is required to collect detailed information on the properties of the seabed and the underlying shallow sediments to build a picture of the local geology of the area and support geophysical data collected.

The geophysical survey will consist of; in-situ penetration testing; borehole sampling via piston coring, vibrocoring or rock coring (substrate pending); and box coring.

The Phase 1 of the survey is planned to start as early as Q2 2020 and is estimated to take 15 days to complete.

The Phase 2 may follow Phase 1 or start as part of a subsequent mobilisation during 2020/2021 and is estimated to take 45 days to complete. Both phases will be completed by December 2021.

The timing of the Survey is dependent upon vessel availability, weather conditions and the receipt of the required statutory approvals.

Dorado FPSO supply competition

The Dorado development is, like the proposed survey, located in WA-437-P where Santos is the operator with an 80 per cent interest and Carnarvon Petroleum is its partner with the remaining 20 per cent.

The preferred development concept is an initial phase of oil and condensate development followed by a future phase of gas export. Shallow water depth allows for simple wellhead platform (WHP) and FPSO development.

Dorado field illustration; Source: Santos
Dorado field illustration; Source: Santos

In an update earlier this week, Carnarvon said that pre-FEED contracts were recently awarded to three contractors.

Under the terms of the contracts, the parties will work independently to advance their FPSO designs and mature their vessel construction plans and supply terms.