Publications

Abstract not provided.

Abstract not provided.

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.

Abstract not provided.

The Geothermal Research Dept. at Sandia Natl. Laboratories, in collaboration with Drill Cool Systems Inc., has worked to develop and test insulated drillpipe (IDP). IDP will allow much cooler drilling fluid to reach the bottom of the hole, making possible the use of downhole motors, electronics, and steering tools that are now useless in high-temperature formations. Other advantages of cooler fluid include reduced degradation of drilling fluid, longer bit life, and reduced corrosion rates. This article describes the theoretical background, laboratory testing, and field testing of IDP, including structural and thermal laboratory testing procedures and results. We also give results for a field test in a geothermal well in which circulating temperatures in IDP are compared with those in conventional drillpipe (CDP) at different flow rates. A brief description of the software used to model wellbore temperature and to calculate sensitivity in IDP design differences is included, along with a comparison of calculated and measured wellbore temperatures in the field test. There is also analysis of mixed (IDP and CDP) drillstrings and discussion of where IDP should be placed in a mixed string.

Abstract not provided.

Using slim holes (diameter < 15 cm) for geothermal exploration and small-scale power production can produce significant cost savings compared to conventional rotary-drilling methods. In addition, data obtained from slim holes can be used to lower the risks and costs associated with the drilling and completion of large-diameter geothermal wells. As a prime contractor to the U.S. Department of Energy (DOE), Sandia National Laboratories has worked with industry since 1992 to develop and promote drilling, testing, and logging technology for slim holes. This paper describes the current status of work done both in-house and contracted to industry. It focuses on drilling technology, case histories of slimhole drilling projects, data collection and rig instrumentation, and high-temperature logging tools.

Abstract not provided.