Hughes Christensen Creates Addtl Slot for Offshore Congo Platform

Hughes Christensen helped a customer in the Congo accomplish a world-first by utilizing an innovative technique to create an additional slot on a platform in the Foukanda offshore field.

The objective was to simultaneously drill and case off over 60 m (197 ft) of shallow formations using Casing-while-Drilling (CwD) to enable the drilling of additional wells from the existing platform that had no further slot availability. A 30-in. diverter conductor pipe was positioned from the platform to the seabed. The pipe was manufactured with a pre-cut window and a 2-degree deflector inside that would allow drilling to be diverted from the existing eight directional wells, avoiding any collision.

The recommended drilling assembly consisted of an EZCase 24-in. bit and 20-in. casing rotated using a drive sub. The 66-m (217-ft) section was drilled successfully with returns to the sea. The EZCase bit and 20-in. casing were cemented in place, and the casing was connected to the surface wellhead as usual. ROP was controlled and averaged 7.5m/hr (24.6 ft/hr) on-bottom drilling, and the bit was drilled out in just over three hrs with a 16-in. GTX-CPT311 TCI bit.