Feasibility study and economic analysis of geothermal well drilling.

This paper reports a comprehensive survey of well drilling time and cost. The models include both specific correlations on various well types and generalised correlations for rough estimation. The models are derived from robust multivariable regression to minimise the residuals. Africa has the highest construction cost component in well drilling and the United States has the lowest. Data in various regions are compared with European and World average drilling data. Drilling time in Italy is similar to Europe and world averages. The proposed model directly estimates both the drilling cost and time to be used in fundamental research and feasibility studies for geothermal power plants applicable worldwide. [ABSTRACT FROM AUTHOR]