Comparison of Rotating Times for Deep Wells

The Department of Energy in the United Kingdom is currently funding studies, at Sunderland and Sheffield City Polytechnic, into the economics of using hot dry rock (HDR) geothermal energy sources. These studies will assist the planning of future R&D strategy and possible commercialisation. Proposed HDR schemes will require wells with the following unusual combination of features: deep (between 3 and 8 kilometres).highly-deviated (up to 30° from vertical).in hard crystalline rockhigh bottom-hole temperatures (between 100 and 300°C) It is expected that the cost of such wells will have a significant effect on the economics of HDR schemes. Hence, it is essential to obtain reliable forecasts of HDR drilling costs. To achieve this, a drilling cost model is now being developed at Sheffield City Polytechnic.