Jetting is the process of using jets of liquid under high pressure to create a guided bore through loose soil, to clear the face of a utility crossing or -with the addition of an abrasive- to clean downhole drilling components. Jetting requires both a high-pressure water source, provided by a compressor, and specialty nozzles attached to the bottom hole assembly (BHA).
Trenchlesspedia Explains Jetting
When creating a guided bore or washing out the face of a utility crossing, the jet of water is directed by the driller to bore through non-compacted soil and loose materials.
A driller can also use jetting to clean downhole components of the mud and muck these tools acquire when working in the bore. This process is known as abrasive jetting. Cleaning downhole components requires the addition of abrasives, such as sand or silica, to the water stream. It also requires special jet attachments called abrasive jetting machinery (AJM) which can be inserted into drill string componentsk cush as drill pipe.