Drill cuttings

Drill cuttings are the broken bits of solid material removed from a borehole drilled by rotary, percussion, or auger methods. Boreholes drilled in this way include oil or gas wells, water wells, and holes drilled for geotechnical investigations or mineral exploration.

The drill cuttings are commonly examined to make a record (a well log) of the subsurface materials penetrated at various depths. In the oil industry, this is often called a mud log.

Drill cuttings are produced as the rock is broken by the drill bit advancing through the rock or soil; the cuttings are usually carried to the surface by drilling fluid circulating up from the drill bit. Drill cuttings can be separated from liquid drilling fluid by shale shakers, by centrifuges, or by cyclone separators, the latter also being effective for air drilling. In cable-tool drilling, the drill cuttings are periodically bailed out of the bottom of the hole. In auger drilling, cuttings are carried to the surface on the auger flights.

One drilling method that does not produce drill cuttings is core drilling, which instead produces solid cylinders of rock or soil.

Drill cuttings carried by mud (drilling fluid) are usually retrieved at the surface of the platform where they go through shakers or vibrating machines to separate the bits and pieces of the cuttings from the drilling fluid, this process allows the circulating fluid to renter the drilling process. cuttings are then studied by mud engineers and well loggers before proper disposal.

Burial is the placement of waste in man-made or natural excavations, such as pits or landfills. Burial is the most common onshore disposal technique used for disposing of drilling wastes (mud and cuttings). Generally, the solids are buried in the same pit (the reserve pit) used for collection and temporary storage of the waste mud and cuttings after the liquid is allowed to evaporate. Pit burial is a low-cost, low-tech method that does not require wastes to be transported away from the well site, and, therefore, is very attractive to many operators.

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