The Wandoo Field was discovered in 1991. Extraction of crude oil commenced in 1993 from a single unmanned monopod wellhead platform (Wandoo A) supporting a helideck and five production wells. The Wandoo B production platform, a Concrete Gravity Structure (CGS) with associated processing facilities, was installed in 1997 and connected to Wandoo A by a subsea pipeline.
The oil produced from Wandoo A (WNA) is piped to the Wandoo B (WNB) platform. After treatment, the oil is stored in the CGS and then, when sufficient volumes are available, offloaded through flexible pipelines to a Catenary Anchor Leg Mooring Buoy (CALM Buoy) located 1.2km north of the WNB platform. A floating hose is used to transfer the oil from the CALM Buoy to export tankers situated at a mooring facility. Export tankers are chartered on a spot basis to offload the oil.
The scope of the well construction operations planned for the Wandoo Field over the next five years includes:
• well interventions and side-tracks;
• construction of new wells;
• abandonment of existing laterals and well bores; and
• slot recoveries.
Timing is based on MODU availability and not restricted to any specific months or seasons of the year. Assessment in this EP have considered all relevant seasonal conditions and factors that may influence the activity and associated environmental impact.
The primary purpose of these activities will be to add new production intervals to access undrained oil in the Wandoo reservoir. A secondary aim will be to continue the evaluation of the field boundaries to determine the extent of the Wandoo reservoir in the areas of the field which the new trajectories will access. This evaluation process will provide critical information for the updating of VOGA’s geological and reservoir models for the field, allowing both the future development and production processes to be optimised.
Drilling of a new well from a recovered slot on WNA or WNB is undertaken if an existing well is first abandoned and the slot recovered for use in a new well. In addition, the existing wells at Wandoo are also candidates for conversion into multi-lateral wells, along with well interventions and well abandonment.
