This chapter provides the basics of equipment and methods used for drilling and completion of geothermal wells. It provides data needed by architects, engineers, and consultants to assist them in specification writing, selection of contractors, and drilling and completion inspection Most direct use geothermal wells can be drilled using conventional water well technology and equipment. Public and drilling crew must be ensured. The cementing portion may appear to be overly detailed and long. However, the author's view is that, all too often, cementing is considered simply as a means of plugging up the annulus between the casing and borehole wall.
Little attention is paid to methods and materials, and a poor cement job is the result.
This can result in lost production zones, cold water leaking into production zones, geothermal water leaking into freshwater zones, and reduced useful well life. Also, in view of the increasing awareness and concern about interzonal migration and possible fresh water aquifer contamination, proper cementing is of increasing importance. A glossary of drilling terms is included at the end of this chapter. For some readers, it may be wise to read this section first in order to fully understand the text.