Boot sub:

During milling, drilling mud under high pressure forces bits of junk up the narrow space between the boot sub and the hole wall.

When the junk reaches the wider annulus above the boot sub and pressure drops slightly, the junk falls into the boot sub.

A boot sub also can be run above the bit during routine drilling to collect small pieces of junk that may damage the bit or interfere with its operation.

Terms Related to Boot sub

• Boot basket

  See boot sub

• Boot

  1. A tubular device placed in a vertical position, either inside or outside a larger vessel, and through which well fluids are conducted before they ...

• Catcher

  A device fitted into a junk basket and acting as a trap door to retain the junk

• Wireline feeler

  A tool used to gauge and clean junk and debris from the casing in conjunction with a junk catcher.

• Junk basket

  May also be called a jet basket: a device with nozzles and a basket or catch basin to catch smaller pieces of junk stirred up ...

• Basket sub

  A fishing accessory run above a bit or a mill to recover small, nondrillable pieces of metal or junk.

• Mill

  A downhole tool with rough, sharp, extremely hard cutting surfaces for removing metal by grinding or cutting. Mills are run on drill pipe or tubing ...