Cementing of geothermal wells

Abstract

The objective of casing cementing, is to provide a complete fill up of cement in the cased hole annulus to resist specific environmental conditions and anchor the casing. In geothermal wells, the cement sheath must also protect the casing against possible corrosion by thermal brines and help prevent the uncontrolled flow of thermal water and steam outside the casing. It is well recognized that good casing cementing is one of the most important factors for long life of geothermal production wells. It has, however, proven to be difficult to get the cement slurry to return to the surface, especially in deep wells with many lost circulation zones. Various methods and materials, mainly from the oil industry have been applied for geothermal drilling and are described in this report. Case histories of casing cementing are presented from Iceland and El Salvador.