ABSTRACT
The success or failure of drilling and completing Geothermal Wells depends reatly on available cementing technology. This requires not only having the knowledge of temperature stable competent materials but also a complete understanding of hole preparation, casing running procedures, mud displacement, lost circulation and the mixing-placing of the cement slurry.
Many steam fields are located where the formation contains poorly consolidated sedimentary deposits, rubblized shales and fractured volcanic rock. These formations are fragile in that some upheaval may have occurred disrupting the structural stability, and with low reservoir pressures, make them prime candidates for lost circulation problems. Many of the geothermal wells have to be drilled through and/or into these fractured formations. Loss of drilling mud or any other fluid put into the hole usually occurs creating problems which are expensive to eliminate. This paper offers methods which have proven successful in combating lost circulation during the drilling and casing cementing operations on geothermal wells located in fields all over the world.
