Friday, February 15, 2019

Finland: How the 15,000 Foot Deep Wells At the Espoo Geothermal District Heating Project Were Drilled

Finland’s Deepest Hole on Record - Otaniemi, Espoo Finland (Numa)

(Courtesy Numa)
USA company Numa, a leading drilling technology provider, has achieved great success in Otaniemi, Espoo Finland by drilling to 15,092 feet (4,600 meters) which is the deepest hole ever drilled in Finland. The geothermal project is part of a wide-scale effort in Finland to reduce the reliance on fossil fuels by finding renewable sources. It is estimated the heat plant will produce up to 40 megawatts of geothermal heat, to supply up to 10% of Espoo’s heating demand.

The geothermal project utilized multi-stage, telescopic drilling methods to reach the desired depths. The first stage used Numa’s Patriot 185 hammer and 26” (660 mm) retained bits with PCD carbide to drill down to 900 feet (274 meters). The second stage used a 17.638” (448 mm) PCD bit to drill down to 9,600 feet (2,900 meters) where the hole was cemented. The third stage used a Numa Patriot 125 hammer specially fitted with fully retained PCD drill bits to ensure strict hole diameter was maintained throughout drilling.  Bit sizes from 12” to 12.500” (305 to 318 mm) were used in stage three until a depth of 15,092 feet (4,600 meters) was achieved.

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