Australian energy giant Santos has secured an offshore regulator’s acceptance of its environment plan for the development drilling and completion of wells on the Barossa gas field development, which is located off Australia.
The National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) informed on Monday that it had approved the environment plan for development drilling and completions, which Santos submitted in October 2021 .
The Australian giant, Santos NA Barossa, submitted it as the operator on behalf of the co-venturer partners SK E&S Australia and Santos Offshore. Located approximately 263 kilometres northwest of Darwin, the Barossa gas field development will backfill the gas supply to the existing Darwin LNG (DLNG) facility at Wickham Point. The first gas production is targeted for the first half of 2025.
Back in March 2018, the Barossa Development Area Offshore Project Proposal was accepted by NOPSEMA and, as a part of the approved development, Santos is planning to start the development drilling and well completions campaign within Commonwealth petroleum production licence NT/L1 in the second quarter of 2022. The regulator explains that the campaign will continue on a 24-hour basis until completed.
Based on the environment plan, the operational area – situated approximately 33 km from the Oceanic Shoals Australian Marine Park – encompasses the entire petroleum production licence with water depths ranging from approximately 204 metres to 376 metres. Furthermore, Santos’ environment plan outlines that six subsea production wells are planned to be drilled and completed around the future locations of three subsea production manifolds, with two wellheads adjacent to each manifold. In addition, up to two contingency production wells could be drilled and completed at any manifold – eight wells in total – if required.
The Barossa environment plan provides for drilling and completing the wells using a semi-submersible mobile offshore drilling unit (MODU) and light well intervention (LWI) vessel, and the ongoing management of the complete wells until future commissioning and production phases.
Moreover, the activities covered by the environment plan are the movement of the MODU within the operational area; MODU and vessel commissioning and demobilising activities; deployment and recovery of the MODU anchors and mooring lines; drilling operations; and well completions, including perforating and well flowback.
Additionally, the activities include the installation of Christmas trees; contingency activities such as side-track drilling, re-drilling sections, re-spud and abandonment; well intervention; ongoing well inspection, maintenance and management; and general operations associated with the use of a MODU, vessels, helicopters and remotely operated vehicles (ROVs) within the operational area.
The offshore regulator explains that a petroleum safety zone will extend in a 500-metre radius around the MODU surface location – at each drill centre – and completed subsea well location, a while cautionary zone will be placed around the MODU and anchors – extending up to 2.5 km from the MODU – during drilling activities. NOPSEMA confirms that this environment plan will remain valid until 31 December 2025.
The Barossa development concept includes a permanently moored FPSO vessel – with a processing capacity for up to 800 million standard cubic feet per day (MMSCFD) of gas and design capacity of 11,000 barrels per day of stabilised condensate – subsea production system, supporting in-field subsea infrastructure in the Barossa field, and a subsea gas export pipeline.
BW Offshore will deliver the FPSO under a contract awarded in March 2021 and sanctioned later that month. The contract is worth about $4.6 billion and BW has already completed the $1.15 billion project debt financing for the construction and operation of the Barossa FPSO. The firm also entered into a partnership with international global infrastructure investors for the equity financing of the vessel.