Cooper Energy (CH) Pty Ltd (Cooper) is the titleholder for Production Licence VIC/L24 (Casino) as well as the nearby VIC/L30 (Henry and Netherby) in the Otway Basin. These permits contain the Casino Henry and Netherby (CHN) gas fields, approximately 30 km southwest from Port Campbell off Victoria’s coast in Bass Strait. The operations and maintenance of CHN is currently managed under an accepted Environment Plan (EP).
Activities are anticipated to commence the first half of 2018. The total expected duration for the Casino-5 workover is approximately 25 days, excluding weather and operational delays. During this period, any of the activities described in the EP may be undertaken, with normal operations conducted 24-hours a day.
In response to a reduction in well integrity, Cooper are proposing to undertake well intervention and work over activities for the Casino-5 well (VIC/L24) in 2018. All activities will be occurring in water depths between approximately 60-70m. The MODU Ocean Monarch has been engaged for this work scope.
Well intervention generally occurs within the wellbore and includes activities such as:
running and testing well control equipment
slickline / wireline operations
well workover including pulling and running tubing / casing
Well Venting and/or flowback activities will need to be undertaken as part of the well maintenance activities and include (but are not limited to):
venting of reservoir gas from the production tubing
venting of nitrogen gas from the production tubing
The MODU will be towed to location where it will be moored prior to commencing activities. Anchors may be placed on the seabed and tested by the support vessels prior to the MODU arriving. Eight anchors will be required, with each having a footprint of approximately 30 m2. Each anchor is connected to large chain (83 mm) which runs along the seabed towards the MODU for approximately 1100 m before rising towards the MODU. A 500-m exclusion zone will be in place around the MODU for the duration of the activities.
The MODU will be supported by two or three anchor handling, tow and support (AHTS) vessels. One vessel will remain on standby and in attendance to the MODU throughout the workover program.
