1. n. [Well Completions]

A downhole device, usually run on slickline, used to remove sand or debris from the bottom of the wellbore. In operation, an atmospheric chamber within the tool is opened to create a surge of fluids into the chamber. Debris is then held within the chamber for recovery at surface.

See: sand

2. n. [Well Workover and Intervention]

Another term for a hydrostatic bailer, a slickline tool generally used for the removal of sand or similar small particles around the fishing necks of downhole tools or equipment. The hydrostatic bailer incorporates a sealed atmospheric chamber and a shear pin, or similar activation mechanism, to allow communication with the wellbore. When the tool is activated, there is a fluid surge into the atmosphere as the pressure is equalized. A shroud arrangement at the base of the tool contains and directs the fluid surge to dislodge and capture any debris in the area.

Synonyms: hydrostatic bailer

See: fishing neck,  shear pin

3. n. [Production Testing]

A swabbing device used to clean up sand that has accumulated in the wellbore. Because sands abrasiveness is detrimental to the normal operation of production equipment, its production should be minimized. A sand bailer operates by creating a partial vacuum that sucks up the sand.