Australia’s National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) is assessing Vermilion Energy’s well construction plan for the Wandoo field located offshore Australia.

Wandoo field; Image: Vermilion

NOPSEMA said that the well construction plan was submitted on January 9, 2020, by Vermilion’s subsidiary Vermilion Oil & Gas Australia Pty Ltd.

According to the offshore regulator, 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 wellbores, and slot recoveries.

The timing of the work is based on rig availability and is not restricted to any specific months or seasons of the year.

NOPSEMA added that the environmental plan had 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 reservoir in the areas of the field which the new trajectories will access.

This evaluation process will provide critical information for the updating of geological and reservoir models for the field.

Drilling of a new well from a slot on the Wandoo A or Wandoo B platform will be done if an existing well is first abandoned and recovered for use in a new well. Also, the existing wells at Wandoo are also candidates for conversion into multi-lateral wells, along with well interventions, and well abandonment.

As for the field, Wandoo was discovered in 1991. Extraction of crude oil began in 1993 from the Wandoo A unmanned monopod wellhead platform supporting a helideck and five production wells. Wandoo B, 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 the A platform is piped to B, which, after treatment, is stored in the CGS and offloaded through flexible pipelines to a catenary anchor leg mooring buoy 1.2 kilometers north of the Wandoo B.

A floating hose is used to transfer the oil from the buoy to export tankers situated at a mooring facility. Export tankers are chartered on a spot basis to offload the oil.