In India, Cairn Oil & Gas, Vedanta Limited wanted to drill a challenging wellbore profile in an 8.5-in section, starting with a vertical drilling ascent and then transitioning to horizontal drilling all in a single trip. The profile was planned in soft and low compressive strength rocks prone to washouts with DLS limited to low angles when using a rotary steerable system (RSS) assembly. To succeed, a drillbit design was required that could deliver the desired dogleg from the PowerDrive Orbit G2™ RSS BHA throughout the interval length.
Using the AccuStrike bit on the PowerDrive Orbit G2 RSS BHA enabled dropping the well from 19° to vertical and then building to 93° at an average DLS of 5.1°/100 ft at just 60% steering force. This DLS output represents an improvement of more than 52% in comparison with the performance of a conventional PDC matrix bit on the same BHA in nearby fields. More than high angle DLS, the AccuStrike bit achieved a consistent 8°/100 ft in a soft sand interval, enabling the customer to position the well at the target zone.
AccuStrike drill bit’s one-piece steel body PDC architecture was instrumental in driving the improvement in DLS. Furthermore, despite facing challenging drilling conditions, the cutting structure showed minimal damage to the cutters, and the bit was pulled out in a condition suitable for reuse.
| Run No. | Drilled, m | From, m MD | To, m MD | From, m TVD | To, m TVD | Formation |
| 1 | 707 | 1,333 | 2,040 | 1,282.43 | 1,757.01 | Predominantly claystone and Predominantly clay stone and landing internal in sandstone |
| Distance, m | Time, h | ROP m/h | |
| Sliding | 0 | 0 | 0 |
| Rotary | 707.00 | 30.50 | 23.18 |
| On bottom | 707.00 | 30.50 | 23.18 |
| International Association of Drilling Contractors (IADC) | 707.00 | 30.50 | 23.18 |
