Government of Indonesia through RUPTL 2021 targets to have around 5,700 MW of geothermal power plant installed capacity in 2030, more than double its current installed capacity. The resource areas are spread throughout the country, and a big part of them is greenfield areas without prior detailed exploration. A low cost and fit for purpose exploration drilling for such fields are crucial to discover and prove the geothermal resources underneath the surface before committing to more massive and expensive development activities. One of the alternatives for exploration and data acquisition is slimhole drilling. Slimhole wells may be drilled in geothermal fields for several reasons, including the relatively low cost, the shorter overall preparation time needed, and the greater geological detail that is obtained from continuously cored holes. Even though slimhole drilling was widely used for geothermal exploration in the 1990s, it has not been extensively used for exploration in the past 10 years, as most developers favor conducting exploration drilling straight to conventional standard or big hole. This resulted in the loss of many lessons learned, best practices, and contractors available to carry out such drilling method. The lack of well-documented and accessible drilling reports and references further worsens the condition. As government and developers in Indonesia seek to reduce the risk and cost of exploring geothermal resource, the lessons learned best practices for slimhole drilling is important to support drilling planning. This paper aims to provide a summary and review related to slimhole drilling operations in the last decade through various published references. The detailed operations, commonly faced problems, and mitigations are highlighted and summarized. It is intended that this paper can increase understanding and knowledge related to slimhole drilling for geothermal exploration and how to mitigate the drilling problem.

Press the Back button in your browser, or search again.

Copyright 2022, Stanford Geothermal Program: Readers who download papers from this site should honor the copyright of the original authors and may not copy or distribute the work further without the permission of the original publisher.