Dorado Development

The scale and quality of the Dorado Project enabled the joint venture to move quickly to the development planning phase. Key milestones towards the Dorado Field Development were achieved during the year, as the project evolved through the pre-FEED workflows before formally entering FEED prior to the end of the period.

Dorado production is planned to be conducted in a multi-phased development with the initial development involving the extraction of the liquids (oil and condensate). The field’s gas and LPG’s will be re-injected before being assessed for subsequent production in a second stage development. The reinjection of gases is expected to considerably enhance the recovery of the liquids from the field. As a result, the initial target gross oil production rate is expected to be between 75,000 to 100,000 barrels per day.

Plans for the phase 1 liquids will consist of a single Wellhead Platform (“WHP”) in 90 meters of water depth, connected to a nearby Floating Production Storage and Offloading (“FPSO”) vessel via sub-sea flowlines and control lines.

The WHP is designed to be a normally unmanned installation with minimal processing facilities. It will be remotely operated from the FPSO using the sub-sea control lines. The pre-FEED work during the year included a tendering process and Concept Select Definition for the construction and installation of the WHP.

The WHP will have the capacity to accommodate up to 16 individual wells from a single drill centre. For the initial Dorado production, the WHP is expected to host 8 to 10 wells, meaning it will have the capacity to accommodate production from possible future tie backs following future exploration successes within the area.

The FPSO is planned to be located around two kilometres from the WHP and will be connected to the seabed by a disconnectable turret mooring system. The FPSO includes the processing facilities for the oil and gas being delivered from the reservoir via the wells and the WHP and allows for storage of oil and condensate as well as offloading to a separate offtake tanker.

Dorado Development (WA-437-P)
(Carnarvon 20%, Santos is the Operator)

The scale and quality of the Dorado Project enabled the joint venture to move quickly to the development planning phase. Key milestones towards the Dorado Field Development were achieved during the year, as the project evolved through the pre-FEED workflows before formally entering FEED prior to the end of the period.

Dorado production is planned to be conducted in a multi-phased development with the initial development involving the extraction of the liquids (oil and condensate). The field’s gas and LPG’s will be re-injected before being assessed for subsequent production in a second stage development. The reinjection of gases is expected to considerably enhance the recovery of the liquids from the field. As a result, the initial target gross oil production rate is expected to be between 75,000 to 100,000 barrels per day.

Plans for the phase 1 liquids will consist of a single Wellhead Platform (“WHP”) in 90 meters of water depth, connected to a nearby Floating Production Storage and Offloading (“FPSO”) vessel via sub-sea flowlines and control lines.

The WHP is designed to be a normally unmanned installation with minimal processing facilities. It will be remotely operated from the FPSO using the sub-sea control lines. The pre-FEED work during the year included a tendering process and Concept Select Definition for the construction and installation of the WHP.

The WHP will have the capacity to accommodate up to 16 individual wells from a single drill centre. For the initial Dorado production, the WHP is expected to host 8 to 10 wells, meaning it will have the capacity to accommodate production from possible future tie backs following future exploration successes within the area.

The FPSO is planned to be located around two kilometres from the WHP and will be connected to the seabed by a disconnectable turret mooring system. The FPSO includes the processing facilities for the oil and gas being delivered from the reservoir via the wells and the WHP and allows for storage of oil and condensate as well as offloading to a separate offtake tanker.

FPSO
Proposed Dorado Field Development Layout.

During the year, the pre-FEED work for the FPSO included a design competition between three leading FPSO vessel contractors who worked independently to advance their FPSO designs and mature their vessel construction plans and supply terms. This competitive process ensures that the Joint Venture is able to consider the optimal technical design, cost and schedule for the provision of the FPSO.

At the end of the financial year, the pre-FEED work was completed enabling the project to formally commence FEED workflows. As a result, in August 2021, an FPSO FEED contract was awarded to Altera Infrastructure Production AS (“Altera”). In addition, the Dorado well head platform contract was awarded to Sapura Energy.

Entry through the FEED gate means that the project is on schedule for a Final Investment Decision around mid-2022.

Exploration – Greater Bedout Area
(WA-435-P, WA-436-P, WA-437-P and WA-438-P)
(Carnarvon 20%-30%, Santos is the Operator)

Carnarvon’s discoveries within the Bedout basin to date have high graded the numerous prospects across the vast acreage Carnarvon holds in the basin. Progress continued towards drilling the Pavo-1 and Apus-1 wells as Carnarvon and the Bedout Joint Venture are accelerating this potential.

On this basis, the Noble Tom Prosser rig has been secured to drill these wells, with the Pavo-1 well expected to spud early 2022. The Apus-1 well will commence immediately following the completion of the Pavo well.

Both wells are targeting prospects with similar interpreted trap, source, seal and reservoir characteristics to Dorado.

Caley
Map of top Caley/TR15 with well locations and significant prospects in the Bedout Sub-basin.

The Pavo-1 well is planned to be drilled in western WA-438-P, and targets mean recoverable volumes of 82 million barrels of liquid hydrocarbons and 108 Bcf of gas in the Caley Fm. The probability of geological success (Pg) is 34%.

Apus-1 is planned to be drilled in eastern WA-437-P. Apus-1 has two targets, with mean recoverable volumes of 235 million barrels and 408 Bcf (combined Caley and Milne Member sands) and a Pg of 23%.

Due to their proximity to the Dorado development, both prospects have tie-back potential to Dorado. Resources capable of being tied-back to existing infrastructure provide significantly enhanced economic outcomes, minimize additional capital investment requirements and shorten time periods to first production from the tie-back fields.

These prospects were progressed for drilling utilising the Keraudren 3D Seismic survey which was acquired in 2019. The Joint Venture also made significant progress in planning for exploration beyond the Apus and Pavo wells by investing in further data acquisitions during the year. Namely, the Archer and Keraudren Extension 3D Seismic acquisitions.

The Archer 3D was primarily acquired over the Dorado field with an alternative azimuth to the existing data sets. This will complement the existing data sets to support the Dorado development and ensure the optimal placement of wells. The Archer 3D also encompassed an area to the south-west of the Dorado field which will allow for a thorough review of the attractive exploration potential in the area.
Given the proximity of this region to the planned Dorado Field development area, any discoveries in this area could be tied back to the Dorado facilities. There is, however, potential for larger discoveries to result in a standalone development.

A fast-track processed volume of the Archer 3D will be available for interpretation later in 2021.

The Keraudren Extension 3D seismic (“KE-3D”) survey commenced following the completion of the Archer 3D acquisition, utilising the same vessel.

The KE-3D survey will cover an approximate 3,200km area (within the WA-436-P and WA-438-P permits) to the northwest of the Dorado development. This area has over 30 prospects and leads already identified using the existing 2D data which will be illuminated by the KE-3D data.

The Archer and KE-3D surveys are important elements towards further unlocking Carnarvon’s commanding acreage in the emerging Bedout basin. There are currently over 200 identified prospects and leads across the Bedout permits, most of which are covered by 2D data. The Archer and KE-3D data sets are expected to enhance some of these prospects for further near-term exploration.