Drilling In The Arctic

The exploration, drilling, production, and transportation practices applied in the Arctic are basically similar to those applied in another places, but there are some extraordinary difficulties.

The permafrost spreads down in the ground for hundreds of meters, but the surface layer melts during summertime. The frozen soil is hard, and can endure almost any weight, but the ground melts if a surface building changes the thermal regime, and the melted soil is often weak and unable to support constructions. The first principle of building on permafrost is to keep the ground frozen. It demands special measures such as insulated piles, open ventilated space under buildings, and active measures to suppress radiation and conduction from the base of buildings.

Most natural resources reserves are several thousand meters below ground, below the base of the permafrost. Air and gas flowing up a mine is hotter than the surrounding frozen soil, and heat conducted outward melts a soil annulus around the mine. The melted soil is wet and mechanically weak, and tends to slump downward, dragging with it the steel casing that stabilizes the wellbore. In extreme cases the casing buckles; insulated casing prevents this as does spacing the wells so that the thaw annuli around them cannot join up.

Mining activities can result in direct and/or indirect impacts on the surrounding environment. Direct impacts of mining activity include tailings, effluents, waste rock, emissions from mining vehicles, erosion and diversion of water. Indirect impacts arise from influx of population, i.e., increased infrastructure, which leads to habitat fragmentation and pollution generally associated with cities (e.g., municipal