Directionally drilling of 16-in hole section in a deep gas field had been always a challenging task to the Operator. This is mainly due to the lithology, consisting of very hard limestone with thin bed of shale where the kickoff would generally start around 11,200 ft.

The operator attempted to kick off the 16-in hole using both roller cone TCI bit and PDC bit technology and utilizing a mud motor as the drive mechanism. This method provided an unacceptable low rate of penetration. In addition, there were difficulties in achieving the directional control, and multiple bit trips were required to finish the required directional work.

The operator determined that a new bottomhole assembly (BHA) would be needed to efficiently drill this section to the desired inclination and azimuth in one run, while meeting the performance requirement. Multi-function teams were organized to aggressively look for new BHA configuration that could consistently drill this interval in one run with a good rate of penetration.

Historically the sliding ROP in the curve section consumes the maximum time (as low as 2-3 ft/hr) with PDC bits and Motor Kick off due to tool face control. To mitigate this, Motorized Rotary Steerable System was selected for this section. The section was kicked off very successfully achieving the required build rates with double the ROP compared to previous wells.

The team collaborated to custom design a new bit and BHA with new drive system that would achieve the operator's objectives. The collaborative effort resulted in achieving new records in drilling, with the fastest ROP, 50 - 100% higher than previous attempts on the fastest offset wells ever drilled in a 16-in hole and precisely drilling to the planned trajectory. The application of this new technology proved to customer that what was not previously possible could be done now more efficiently and cost effectively.

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