Publications

Drilling technology in geothermal fields adopts techniques from oil and gas drilling technology. Most geothermal wells are designed following the same principles as those used in the oil and gas industry. Some simple comparisons between wells used for geothermal applications with those for oil or gas production show that the former need to be larger bore, deeper and are operating longer.Although geothermal reservoirs and oil/gas reservoirs are similar, the facts show that there are several differences that cannot be ignored. When drilling procedures in oil/gas fields are applied to geothermal fields, those differences have a significantly adverse impact on geothermal drilling if they are not taken into account. Therefore, it is necessary to define the main differences between geothermal fields and oil/gas fields, and then to consider those to come up with a superior geothermal drilling design. The main challenges associated with drilling geothermal wells are related mostly to the hardness of igneous and metamorphic rock being drilled, rock that is not commonly found in oil/gas well drilling, the unusually high temperature of the formation (average temperature gradient for a oil/gas well is 5oF/100 ft and 12o - 13o F/100 ft or could be more for geothermal well) and the typically under-pressured strata (Ullah and Bukhari, 2008).This paper summaries the drilling fluid, cement, casing, drillstring, all commonly used in geothermal drilling. Formerly, defining main characteristics of geothermal field was also important in defining those differences, and applying a different design to geothermal drilling in order to minimize adverse impacts, such as casing failures, cement failures, drilling fluid failures etc, caused by high temperatures. Casing design will be discussed more thoroughly due to many casing failure problems in the geothermal industry as an oil/gas principal.The last, geothermal drilling in some countries will be updated in this paper, in order to share news and suggestions about our geothermal industry.Keywords: Geothermal Drilling, Geothermal Technology, Geothermal in Indonesia.