Challenge: A geomechanics and rock strength analysis (RSA) performed before drilling identified an extremely hard formation. With the RSA, the Schlumberger team developed a drilling strategy that minimized slow drilling times while ensuring borehole stability and trajectory.
One of the main challenges during the drilling phase was the use of water-base mud. A potassium chloride–polymer system—combined with proven engineering procedures—provided good hole-stability characteristics.
Solution: The IPM team assisted the client in selecting fit-for-purpose solutions to meet the key exploration objectives.
The LiteCRETE lightweight cement slurry system permitted the 9 5/8-in casing string to be cemented in a single operation.
The wells were drilled in an area where changes in water salinity made conventional log interpretation difficult. The initial data acquisition program was adapted to include more advanced logging technology to better evaluate the formation.
Results: FMI fullbore formation microimager data showed an Ordovician oil zone with extremely low permeability to be naturally fractured. As a result, the client requested an alternative liner configuration, which was quickly designed and successfully implemented. This solution avoided cementing the natural fractures in one reservoir zone but still allowed isolating other reservoir zones that were higher up in the wellbore. Results from well tests proved the success of this approach.