The Ichthys Field is in petroleum production licence WA-50-L in the Browse Basin about 220 kilometres off the north west coast of Western Australia and 820 kilometres south west of Darwin. The Ichthys Field development in WA-50-L, operated by INPEX, consists of a central processing facility (CPF) and interlinked floating production, storage, and offtake facility (FPSO) with a number of satellite drill centres consisting of manifolds and subsea wells tied back to the CPF. Hydrocarbon production involves gas from the Ichthys Field undergoing preliminary processing at the CPF to remove water and raw liquids, including the greater part of the condensate. This condensate is pumped to the FPSO for further processing and then periodically transferred to offtake tankers for export to overseas markets. The gas and some condensate are transported along an 890-kilometre-long subsea gas export pipeline (GEP) for further processing onshore at Bladin Point in Darwin. Operations are ongoing on a continuous 24/7 basis.
This EP is the first 5-year EP revision for the operation of the Ichthys Project offshore facility and covers the next 5 years of the expected 40-year Ichthys field life. In addition to continuing production operations, the interlinked facility will undertake shutdown periods to conduct maintenance activities and to allow for the installation and commissioning of new equipment and infrastructure over this time. To account for future decline in reservoir pressure over time, space and weight has been reserved for a Booster Compression Module (BCM) to be installed on the CPF. The BCM installation is currently scheduled for the 2024 – 2025 period. During periods of intense activity such as shutdowns/BCM installation an accommodation support vessel will be required to accommodate additional personnel.
During the life of this EP, inspection, maintenance repair activities may be required to ensure the safe and efficient operation of the infrastructure. Inspection activities, generally involving the use of a support vessel and remotely operated underwater vehicles include, but are not limited to, inspection of the CPF and FPSO hulls and subsea infrastructure. In addition, marine acoustic surveys (e.g. side scan sonar and multibeam echo sounders) may also be undertaken. These inspections are typically conducted from a vessel or autonomous underwater vehicle fitted with acoustic instruments. The exact frequency and nature of inspection activities is risk based and will depend on the specificities of individual systems/equipment. As part of planned maintenance and coinciding with a major shutdown, INPEX plans to insert an inline pigging tool to assess the internal wall of the GEP. This activity will involve the use of a vessel to lower a Pig Launcher Receiver (PLR) which will be attached at the Gas Export Riser Base (GERB) located in WA-50-L. Once installed, the PLR pushes the pig from offshore along the length of the GEP to the Ichthys LNG onshore plant and is currently scheduled for the 2022-23 period and is expected to last for at least 7 days. The PLR will remain in-situ and be recovered from the GERB during the scheduled 2024 shutdown.