Improve angle buildup and well trajectory

Vankorneft drilled liner sections across 28 wells in an eastern Siberia field, including five sidetrack wells, two of which were drilled in the same well on separate runs. Several of the sections began facing angle buildup and well trajectory issues. The 6-in directional PDC bits that were being used did not provide the intensity required to meet the zenith of the angle buildup.

Develop a fit-for-purpose drill bit

Schlumberger collaborated with Vankorneft to optimize the operation. The push-the-bit PowerDrive X6 RSS was recommended to provide full directional control while rotating the drillstring for increased dogleg capability in challenging environments. Engineers from Smith Bits, a Schlumberger company, used the IDEAS platform to identify the optimal placement of the managed depth of cut (MDOC) feature—used to stabilize torque while limiting cut penetration—because improper placement can lead to reduced DLS. Determining which cutters required the MDOC feature increased tool face control and contributed to higher DLS with the PowerDrive X6 RSS combination. Custom-purpose bits were developed, field tested, and implemented to maintain the maximum RSS inclination of 2.5°/30 m to 5°/30 m when drilling the sections.

Achieved drilling objectives, increased ROP

Using the recommended solution, Vankorneft increased its average ROP per section by 12% when comparing rates before and after the change in BHA. The 1,194-m sidetrack well was drilled in a single run using the new PDC drill bit design. The optimized BHA also increased DLS to 5°/30 m, a 40% improvement over the original configuration.