What Does Debris Mean?
Debris is the organic detritus of drilling. This includes materials ranging from grease, stale, half-eaten sandwiches unthinkingly thrown on the ground, and human waste. Excess sand and gravel or sand and gravel removed from a bore, although inorganic materials are also considered debris.
It may also include organics not brought to or produce on-site by humans, such as tree roots, wood and dead animals.
When trapped in the borehole, debris can cause problems making it difficult or impossible to recover drill pipe, bits or other bottom hole equipment.
Trenchlesspedia Explains Debris
Junk of one sort or another accumulates on a trenchless construction location just as it does on any construction site. Goods come to the site in cardboard boxes, wrapped in plastic. Workers bring beverages in aluminum cans and plastic bottles and lunch in plastic, aluminum foil or paper.
Small, dead animals may be present before the rig arrives or the project begins. The material that comes from the borehole or, in a small amount of the slurry used to create the borehole may escape from recycling may be left after the project is done and before site cleanup commences. All of this is and more is part of the debris associated with trenchless construction.
Tools that fall into the borehole - or bits that break or the drill pipe that bends when in the hole -- are also debris that can "jam up" drilling. Recovery of these items is expensive, involving a process called "fishing," which uses a wireline unit to "fish" the offending materials or tools from the hole.