Clay minerals: from the micro-analytical detection to the impact on geothermal systems in Indonesia and the Netherland

Indonesia with its large, but largely unexplored geothermal potential is one of the most exciting and suitable places in the world to conduct geothermal exploration research. This study focuses on geothermal exploration based on fluid-rock geochemistry/geomechanics and aims to compile an overview on geochemical data-rock properties from important geothermal fields in Indonesia. The work will be conducted over the next two years and this paper intends to present the methods and approaches we would like to use. The research carried out in the field and in the laboratory is performed in the framework of the GEOCAP project (Geothermal Capacity Building program Indonesia-the Netherlands). Because of their relevance and geological setting representing geothermal fields in Java and Sulawesi and the sedimentary basin of central Sumatra will be the focus areas of the study. It covers operating and exploration fields . The exploration activity in the operating fields will target to a better knowledge of the rock and fluid composition (core samples, surface and bottom hole samples). Geomechanical experiments will be conducted on different type of rocks (basalts and pyroclastics with different permeability and porosity) to improve the availability of rock properties data. The multi-disciplinary approach analysing the samples by different means (Scanning Electron Microscope SEM, Electron Microprobe EMP, X-ray powder diffraction XRD, X-ray fluorescence XRF) will deliver a best practice guide on how to explore fields with different geological backgrounds and provide an overview of different geothermal areas. Operators, universities and governmental agencies will benefit from this approach as it will be applied also to new green-field regions and areas to be tendered.