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Cost-efficient Drilling of Deep Geothermal Well
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, The Third Sustainable Earth Sciences Conference and Exhibition, Oct 2015, Volume 2015, p.1 - 5
Abstract
The total cost for deep geothermal boreholes used for heating and electricity is characterized by high investments.
The investments consist of the cost for the geological surveys, the drilling and completion as well as the installations on the surface. As the well cost is making about 70 % of the total investment for geothermal electrical power stations, the greatest potential for cost savings is for drilling the well.
Several factors do have a great influence on the drilling cost for a well.
The borehole design: the cost is increasing disproportionately high with increasing borehole diameter. The development concept for a geothermal project must consider the additional cost for more single rig sites (vertical wells) with higher rig move cost and surface pipeline connections between the sites vs. multiple wells from one cheaper rig site with the risk for highly deviated directional wells.
Longterm drilling contracts including rig sharing with other developers with defined and optimized drilling sequences will reduce transportation cost and dayrates as well as gain from the experience of multiple projects („lessons learnt”).