The Anshof onshore oil field is located in the ADX-AT-II exploration licence area in Upper Austria.
ADX Energy (ADX), an oil and gas production and exploration company based in Australia, owns 100% equity interest in the licence. It holds an 80% stake in the field and serves as the operator. The remaining 20% working interest is held by Xstate Resources, an oil and gas company based in Australia.
Xstate Resources provided funds equivalent to 40% of the well-drilling costs in exchange for the 20% interest in the field, as per the farm-out agreement announced by ADX in November 2021.
The Anshof field secured final environmental authority approvals and started onsite drilling operations in November 2021. ADX received approval for drilling up to three locations over the Anshof well site in 2021.
The production-testing targeting Eocene oil reservoirs was started in October 2022. The production licence for the Anshof field was awarded to ADX in March 2023. It includes the regulatory framework for further development of the Anshof oil field.
Geology and oil reserves
The Anshof prospect is a modern 3D seismic-covered Eocene – Cenomanian prospect. Eocene oil found in the field is high-quality sweet crude.
The field is estimated to hold proven and probable reserves of 5.2 million metric barrels of oil equivalent (Mmboe) as of October 2022.
Anshof field discovery and exploration
The Anshof field was discovered in January 2022 via Anshof-3 well. This well was spudded in December 2021 and was drilled using the RED E200 rig. The field will produce from three wells: Anshof-1, Anshof-2 and Anshof-3.
Anshof-1 well is the first exploratory well in the ADX Upper Austria exploration programme. The well’s primary target was the Eocene sandstone reservoirs, estimated to hold 6.6 Mmboe in reserves. The well is anticipated to reach a drilling depth of 2,000m. A deeper Cenomanian reservoir will be a secondary target, having a potential of 2.1 Mmboe.
Anshof-2 well will appraise the extent of the down-dip oil in the structure. It is expected to be a high-angle well optimising the lateral intersection of the Eocene reservoir, resulting in efficient oil flow and optimum reserves recovery.
Anshof-1 well is proposed to be drilled as a producer in a more crestal part of the structure. The drilling of Anshof-2 is expected in the third quarter of 2023, while Anshof-1 is anticipated to start within 12 months.
Anshof field development
The oil from the wells will be produced through a leased early production unit (EPU). The rented unit involves oil and gas separation facilities, power generation, well site storage, off-loading, and telemetry control systems. It is currently established at Anshof-3 well location. The EPU permits smooth production of oil from the well with limited operator intervention.
Anshof-1 and Anshof-2 wells are also planned to be drilled from the leased early production unit used by Anshof well-3.
The wells are proposed to target thicker reservoir intersections on the 25km² mapped Anshof structure.
The site construction work and cellar installation are expected to commence between March and April 2023.
Anshof-3 well production testing
The Anshof-3 well commenced production in October 2022. The production from Anshof-3 was initially maintained at a constant average rate of 113 barrels of oil per day (bopd) due to limited onsite day storage capacity and limitations on truck movements to transport the oil to a terminal for final processing.
The average production capacity is expected to increase to 150 bopd with an expansion of crude oil storage capacity, anticipated in the second quarter of 2023. The oil will be processed by the EPU and transported to the OMV refinery near Vienna.
RED Drilling & Services, a drilling solution provider and a subsidiary of UOS Drilling, was contracted for drilling the field’s wells in November 2021. The contract is for a period of three years and will involve drilling multiple wells, subject to the availability of rig slots.
RISC Advisory, an independent advisory firm based in Australia, carried out an independent prospect review of the project.