Rock mechanics applied to drilling-an operational review

摘要

This paper gives effective procedures to drill wells in a depleted reservoir. From the fact that depletion result in decreased horizontal stresses and fracture gradients. the working hypothesis is that a depleted reservoir should be drilled by keeping the Equivalent Criculating Density (ECD) as low as possible. This have been achieved by using a low mudweight and applying the downhole pressure sub actively; which imply focus on the combination of hole eleaning, lower pump rates, avoiding backreaming, and careful breaking of circulation before pumps are started.