Some Geological and Geophysical Aspects of Geothermal Exploration in the Netherlands

Abstract

The first geothermal doublet was realized in 2007 in the West Netherlands Basin in Cretaceous sandstones at a depth of approximately 1650m. Water at approximately 600C is pumped up through the production well. Heat is extracted and the cooled water is pumped back into the same formation using a second well. The distance between producer and injector in the aquifer is approximately 1200-1500m. The extracted thermal energy is used for greenhouse heating. This success was followed by eight doublets and plans for more. The driving force is demand for heat by greenhouse complexes combined with availability of subsurface data (well logs and seismic) from oil and gas exploration. Geothermal exploration is very similar to exploration for hydrocarbons. The aim of geothermal exploration is to locate permeable and thick sandstone formations that can sustain production and injection rates in the order of 150-250m3/hour. Using simple reservoir models, the cool temperature-front of robust prospects is expected to reach the producer after 25-30 years. The geology of the areas and basins with realized and planned geothermal reservoirs and the experiences with realized geothermal wells will be discussed.