1. vb. [Drilling]
To take apart, disassemble and otherwise prepare to move the rig or blowout preventers.
See: blowout preventer, rig
2. n. [Well Completions]
The process of disassembling well-control or pressure-control equipment on the wellhead. Depending on the configuration of the wellhead and casing strings, it may be necessary to nipple-down and nipple-up the blowout preventer (BOP) system as each casing string is run.
