Objectives: The properties of various potential geothermal reservoir rock types will be determined and processes related to flow and to the jetting of the rocks will be investigated at the laboratory scale. One of the crucial questions addressed is the way in which the micro-scale processes, controlling the flow and heat transfer will behave at a larger scale. It is of critical importance to better understand the physical, mechanical and chemical properties and their dependency on mechanical and chemical reservoir conditions of the tested reservoir rocks. To generate these data and derive the necessary information detailed laboratory and numerical studies will be performed at micro (laboratory)-scale, with and without the drilled laterals. The knowledge gained within this WP including the rock properties and constitutive relations will be used in WPs 5-7.The objectives are to: