John Travis Finger

Slimhole Handbook: Procedures and Recommendations for Slimhole Drilling and Testing in Geothermal Exploration

This Handbook documents R&D projects completed in-house and third-party R&D sponsored by Sandia National Laboratories in the Slimhole Drilling Program. It comprises: narrative accounts of field drilling projects, compilation of test data from Sandia projects and synopsis of data from Japanese boreholes, descriptions of in-house and other analyses of the data set, descriptions of drilling and logging equipment available for slimholes, and guidelines for drilling and testing geothermal slimholes.

Investigation of Percussion Drills for Geothermal Applications

A series of tests was conducted to provide data for an economic evaluation of percussion drilling in geothermal reservoirs. Penetration rate, operation on aqueous foam, and high temperature vulnerabilities of downhole percussion tools are described.

Development of a system to provide diagnostics-while-drilling.

This report describes development of a system that provides high-speed, real-time downhole data while drilling. Background of the project, its benefits, major technical challenges, test planning, and test results are covered by relatively brief descriptions in the body of the report, with some topics presented in more detail in the attached appendices.

Research and Development Activities in Geothermal Drilling, Completion, and Logging

Sandia National Laboratories manages the Geothermal Drilling and Completion Program for the US Department of Energy. The primary purpose of this program is to expand access to the geothermal resource by reducing the cost of drilling and completing geothermal wells. This cost is typically two to five times that for an oil well of comparable depth, and well cost is usually about half the total capital investment for a geothermally-powered plant to generate electricity.