Borehullet

Borehullet is the Norwegian term for a borehole—a narrow, drilled shaft that extends into the subsurface. Boreholes are created with drilling rigs and are used to access subsurface resources, obtain groundwater, install monitoring equipment, or gather geological data. The design and execution depend on purpose, geology, and depth.

Drilling methods include rotary drilling, where a rotating drill string cuts rock, and percussion or hammer drilling for harder formations. After reaching target depth, a casing is driven or cemented in place to prevent hole collapse and to protect aquifers from contamination. In water-supply wells, screens and gravel packs may be installed to filter sediment and stabilize flow. For geothermal or hydrocarbon wells, select casings, packers, and sometimes production tubing are used to control production and isolate zones.

During construction, boreholes are logged with various measurements—geologic or lithologic logs, resistivity, gamma rays, and temperature logs—to characterize rocks and fluids. Core samples may be recovered for analysis. Once the borehole has served its purpose or when it is decommissioned, it is sealed with cement plugs and proper abandonment procedures to prevent leakage and groundwater contamination.

Safety and environmental considerations include preventing aquifer contamination, managing drilling waste, and securing boreholes against collapse or unauthorized access. Regulations often require reporting, permitting, and verified plugging when a borehole is no longer in use.