Shell Brazil had been drilling deepwater wells targeting reservoirs located 1,000 m or less below the mudline. To drill the wells’ reservoir sections horizontally, it was necessary to build angle in their tophole sections, which was difficult because the formations were soft and unconsolidated. Tophole sections of the initial wells were drilled with motors and 16-in tricone bits. These BHAs were sliding two-thirds of the time—limiting average ROP to about 10 m/h— and could only achieve inclinations between 21° and 36° by section TD.
In addition to the PowerDrive Xceed RSS, the BHA included a 17½-in XR+VE3JPS tricone bit, which improved hole cleaning by eliminating the need for an under-reamer. The BHA also included an arcVISION825 8¼-in drill collar resistivity tool, and the TeleScope high-speed telemetry-while-drilling service. The arcVISION825 tool provided array compensated resistivity and APWD annular pressure-while-drilling measurements that were sent to the surface in real time by the TeleScope service, along with vibration and IWOB integrated weight-on-bit measurements.
Despite the soft, unconsolidated formation, the point-the-bit PowerDrive Xceed RSS achieved an inclination of 49.7° at section TD, with an average DLS of 2.4°/30 m. ROP averaged 45 m/h and at times reached 80 m/h. The high-quality borehole enabled the drillstring and BHA to be tripped out of the hole with minimum drag and the 13⅜-in casing string to be run to bottom. This performance made this PowerDrive Xceed BHA the front runner for upcoming campaigns involving eleven 17½-in tophole sections and for development of a potential field to produce a relatively shallow reservoir roughly 700 m below the mudline.
