Hammer Drilling Technology for Geothermal Deep Drilling within the Crystalline Basement

Dominik Lorber

Research output: ThesisMaster's Thesis

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Main goal of this study is to give a well-structured overview of potential technologies and approaches on how to drill hard and abrasive formations typically encountered when drilling for geothermal resources within the crystalline basement. The thesis will follow the percussive hammer drilling approach more closely. It will deal with a technical and financial evaluation of the hydraulic and air hammer technology compared to conventional drilling methods based on project data from a planned geothermal development. A thoroughly researched literature review covering the topics of conventional drilling, fluid systems and additives, and hammer drilling with a special focus on air hammer drilling, all in relation to geothermal deep drilling within the crystalline basement, is presented within the thesis. Knowledge gained throughout the literature review and expert interviews allowed to elaborate necessary equipment and basic technical requirements to perform air hammer drilling within the planned project. Obtained required equipment and necessary services form the basis of air hammer related tender documents which allowed to receive informative equipment and service prices related to air hammer drilling. Furthermore, a Monte Carlo simulation is used to produce probabilistic well construction times considering the two different drilling approaches. Received prices and elaborated air hammer drilling related quantities allowed to perform an economic analysis comparing the air hammer and conventional drilling approach. This study provides an overview of state-of-the-art concepts and approaches related to deep drilling within crystalline rocks. Other results are dimensioning of an appropriate air package, calculation of air hammer operating parameter and elaboration of suitable subsurface as well as surface components to allow for a functional air hammer drilling system. Furthermore, this study developed a tool to assess the economic viability of the hammer drilling technology compared to conventional deep geothermal drilling within the crystalline basement. The results of the performed economic analysis are based on recent industry prices and obtained time dependent and time independent quantities elaborated throughout the thesis. The thesis provides a novel approach allowing to estimate and compare economic viability of air hammer drilling in contrast to conventional geothermal basement drilling.
Translated title of the contributionImlochhammerbohrverfahren für geothermische Tiefenbohrungen im kristallinen Grundgestein
Original languageEnglish
Awarding Institution
  • Montanuniversität
  • Fazeli Tehrani, Fatemeh, Co-Supervisor (internal)
  • Lackner, Daniel, Supervisor (external)
  • Lentsch, David, Co-Supervisor (external)
  • Hofstätter, Herbert, Supervisor (internal)
Award date18 Dec 2020
Publication statusPublished - 2020

Bibliographical note

embargoed until null


  • Down the Hole Hammer Drilling Technology
  • Geothermal
  • Hard Rock Drilling
  • Hydraulic Hammer
  • Pneumatic Hammer
  • Underbalanced Drilling
  • Foam Drilling
  • Air Package
  • Economic Analysis

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