AGR’s Australian team were engaged by the Victorian Government to execute the abandonment of the region’s first offshore CO2 sequestration appraisal well. Originally drilled by AGR, the well was designed to be suspended in due course, in place for further development. But plans changed and the client decided to permanently abandon the well during operations.
Location
The Pelican storage site is located in the Gippsland Basin, approximately 8km off the coast of Victoria.
The Challenge
Anything but a routine abandonment operation, with a number of complications to overcome
- During well operations, it was recognised that a thief zone, that was not present in offset wells, was encountered above the reservoir seal. Although this had no bearing on the success of the appraisal well and the field’s future development, it did complicate well abandonment operations as the cement in the liner did not sufficiently cover a shallower water bearing zone. This required an alternative solution in a short timeframe to reliably plug and abandon the well in accordance with regulatory requirements
- The short timeframe could create problems in mobilising equipment and personnel for this challenging operation. Limited availability of section milling equipment in Australia complicated things further.
- Casing swarf recovery equipment with the rig equipment required.
- An abandonment design suitable for a well situated in a potential CO2 storage site was urgently required.
- Bushfires in Victoria, ongoing while the abandonment was in operation, impacted logistics seriously. Special arrangements and expertise were needed to meet equipment and personnel objectives.
The Solution
Despite the difficulties a perfect abandonment was accomplished, on time
- All logistical challenges were overcome with no impact to the critical path of operations
- Equipment came from four different countries and multiple locations locally for the section milling operation.
- We achieved the effective recovery of casing swarf during section milling operations.
- Plug and abandonment operations were successfully executed without incident, all environmental commitments met and with no downtime waiting on equipment.
- The well was accepted as permanently abandoned by the regulator NOPSEMA.
