Offshore Appraisal Well

The CarbonNet Project successfully completed drilling an Offshore Appraisal Well (OAW) on 24 January 2020 at the Pelican site in Bass Strait.

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OAW outcomes

The core sample extracted from our OAW was analysed during 2020 with the geology of the Pelican site receiving top marks from industry experts.

Prior to OAW operations commencing, the CarbonNet team had made predictions on thickness, distribution, and quality of the different rock layers within the Pelican site. The pre-drill models were generated using data from the 3D seismic survey conducted in 2018 and the extensive geological data collected from the Gippsland basin over the past 50 years of oil and gas operations.

This existing data has now been checked against the OAW results with positive outcomes. All layers were found as predicted, down to almost 1500m below seabed (i.e. to 99% accuracy). The lithologies were very close to those forecast with only minor local variations. The geological model for the storage site will now be updated with new information, with only minor changes anticipated.

During the well operations valid pressure seals were found, and excellent reservoir properties were measured in a 24-hour injection test of sterilised water. Results to date are extremely positive and in line with expectations for Pelican to take over Five Million tonnes of CO2 per year.

Technical overview of OAW:

  • Location optimised, using 2018 3D seismic survey
  • Drilled to Total Depth of 1523m MD, in the storage reservoir
  • Stratigraphy as predicted
  • Depth forecast accurate (+ 15m)
  • 89m core recovered (seal and reservoir)
  • Extensive wireline logging program
  • 24-hour water injection test up-to 10,000bpd
  • Seals present
  • Reservoirs better than predicted (multi-darcy)
  • Well plugged and abandoned, in accordance to regulatory requirements

Additional data about rock strength, regional tectonic stress, reservoir and seal chemistry/mineralogy, and subsurface fluids was acquired and are now being incorporated into updated models.

The core analysis process has specifically included:

  • Describing the minerals, layering and grain size variations to interpret the environmental conditions sediments were deposited.
  • Porosity and permeability measurements at reservoir condition to confirm the storage capacity and injection potential of the Pelican site.
  • Specialised permeability measurements using CO2 at reservoir conditions. This will allow refinement of reservoir models of the injected C02 over the life of the project.
  • Rock strength measurements to calibrate a geomechanical model of the Pelican site.

OAW Environment Plan

The Environment Plan for this activity was approved by the regulator, National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA), in April 2019.

View the Environment Plan Summary on the NOPSEMA website.

Drilling operations

The Noble Tom Prosser drilling rig arrived in Melbourne's Port Phillip Bay onboard the OHT Osprey (heavy lift vessel) in November 2019.

Our video shows the drilling rig being 'floated off' from the Osprey, prior to being towed out of the Bay towards its final destination - CarbonNet's Pelican site in Bass Strait, arriving on 1 December 2019.

The CarbonNet project has reached an important milestone with our drilling rig, the Noble Tom Prosser, having arrived in Melbourne's Port Phillip Bay on 27 November onboard the OHT Osprey (heavy lift vessel).

Our video shows the drilling rig being 'floated off' from the Osprey, prior to being  towed out of the Bay towards its final destination - CarbonNet's Pelican site in Bass Strait (arrived 1 December).

Once onsite, the rig was positioned approximately 8km offshore from the Ninety Mile Beach in Bass Strait from December 2019 to January 2020. The rig drilled to a depth of about 1.5km below the seabed in order to extract approximately 90m of core sample for analysis purposes.

Diagram of a typical offshore jack-up drilling rig. The total depth of the appraisal well is 1,500 metres.


A 500m radius safety exclusion zone was in place around the drilling rig for the duration of operations.

The activity was managed by AGR (Australia) Pty Ltd as the Drilling Management Contractor for CarbonNet.

Location

The OAW location was the Pelican site, approximately 8km offshore from the Ninety Mile Beach in Bass Strait, as shown on the map below.

CarbonNet's Offshore Appraisal Well near Golden Beach and Paradise Beach, approximately 8 km offshore in Commonwealth waters

Timeframe

Drilling operations took approximately 55 days to complete over December 2019 and January 2020.

More information

Page last updated: 09 Feb 2021