In a multiyear, multiwell drilling program in Kazakhstan, Karachaganak Petroleum Operating (KPO) wanted to restore production in a nonproducing well. To accomplish this, KPO needed to drill a 6-in sidetrack from a whipstock installed at a near-vertical inclination and land the well at 86°, which would require a dogleg of 6°/30 m to 9°/30 m.
In the past, KPO used conventional RSS BHAs to achieve time and tortuosity gains. However, for dogleg assurance reasons, the build section could only be drilled with mud motors, which required multiple bit runs. KPO wanted to drill the 6-in reentry well more efficiently than previously had been possible to help restore production to nonproducing wells.
SLB recommended drilling the high dogleg severity (DLS) curve using the PowerDrive Archer 475 high build rate RSS, a highly reliable hybrid steering system with a dogleg capability of 18°/30 m [18°/100 ft]. Using the IDEAS™ integrated dynamic design and analysis platform, Schlumberger also selected an application-specific directional PDC bit from Smith Bits, an SLB company, for use with the PowerDrive Archer RSS to provide greater directional response, minimal vibration, and high ROP.
The PowerDrive Archer 475 RSS and PDC bit were run from the whipstock window to TD, a total of 1,362 m. The well was placed precisely at the required TVD using a hold-inclination-and-azimuth command in the lateral section.
This BHA enabled KPO to drill the reentry well in one run at a record ROP of 8.6 m/h for the field and achieve the planned dogleg of 6°/30 m to 9°/30 m. The sidetrack was completed 8.5 days ahead of schedule, which was based on past experience using conventional mud motors. The time saved with the PowerDrive Archer RSS reduced operating cost by USD 2 million, and KPO plans to use this method to restore production in other nonproducing wells in its drilling program.
