1. vb. [Drilling]

To enlarge a wellbore. Reaming may be necessary for several reasons. Perhaps the most common reason for reaming a section of a hole is that the hole was not drilled as large as it should have been at the outset. This can occur when a bit has been worn down from its original size, but might not be discovered until the bit is tripped out of the hole, and some undergauge hole has been drilled. Last, some plastic formations may slowly flow into the wellbore over time, requiring the reaming operation to maintain the original hole size.

See: underream