The four-well conductor removal project in Brunei was completed with an existing rig on a multi-slot platform, and involved the removal of multiple casing strings in various sizes and configurations. With each well, the time and efficiency improved. The first well involved laying down six 12 m (39 ft) sections of 133⁄8-in.-by-20 in.-by-26-in. casing. The job was completed in 38 hours, including 90 minutes average boring time and 60 minutes average cold-cutting time.
Based on lessons learned in the first well, the second operation was completed in 24 hours, and involved laying down five 12-m (39-ft) sections of 20-in.-by-30-in. casing. Average boring time was reduced to 60 minutes and average cold-cutting time maintained at 60 minutes. Conductor removal on the third well took 24 hours, with average boring time improving from 60 to 40 minutes. The job involved laying down six 12-m (39-ft) sections of 20-in.-by-30-in. casing. Average cold-cutting time remained at 60 minutes.
The fourth well showed the most improvement in time, with the operator laying down six 12-m (39-ft) sections of 185⁄8-in.-by-30-in. casing in 22 hours. Average cold-cutting time remained at 60 minutes; however, average boring time improved from 40 to 30 minutes. In all operations, the boring, pinning, cold-cutting, and laying-down activities were completed safely with no lost time incidents or environmental events, with total conductor removal completed in 108 hours.
In situations where a rig is not available or where space and structural limitations and/or downgraded and damaged derricks prevent the use of a rig, a light-duty pulling and jacking unit (P&JU) that can handle conductors up to 36-in., pull 13,607 kg (30,000 lb) and jack (13,607 kg) 1 million lb is available. The unit has a hydraulically-powered telescoping mast positioned just above the well center, allowing the BOP to be positioned underneath in compliance with regulatory requirements and the ability to accommodate changing well conditions. The P&JU also has an integrated jacking system and power swivel stand that requires minimal rig-up time. It is equipped with a self-clamping system and can skid from well to well on a platform.
Abandonment is the final and inevitable stage of every well. Safe and efficient P&A programs, including conductor removal, are increasingly becoming a priority for production companies to ensure they are in regulatory compliance, maintain high environmental standards, and can move forward with new exploration and production initiatives. An integrated portfolio that provides the necessary fit-for-purpose and latest technologies and expertise, as well as flexibility, is critical in carrying out complex conductor removal operations efficiently, while avoiding risk, and NPT remediation costs.