Exploration and exploitation of geothermal reservoirs
The main task is to create innovative methods of geothermal exploration. Geophysical survey methods are currently capable of depicting subsurface geological structures. However, knowledge on the reservoir properties of the target horizons is the information most needed. The solution lies in the combination of various geophysical methods describing the subsurface with laboratory experiments on rocks. Such an integrated interpretation will use laboratory experiments of the reservoir rocks under in-situ conditions (temperature and pressure) to gain knowledge of material properties. These are incorporated into dynamic models of the temperature and flow field and their evolution with time and are complemented with measurements in boreholes as well as surface geophysical surveys in the vicinity of these boreholes. In this manner all spatial and temporal scales of the system can be considered. These activities are planned and will be performed in close cooperation with other research institutes and industrial partners. A national example is the investigation of the deep flow field in the North German Basin and an international project will study the fluid phase conditions (liquid and steam) in the vapour-dominated geothermal resources in Tuscany, Italy.
Reliable operation of the thermal fluid cycle and warranted energy supply including the conversion of low-enthalpy heat into electricity
New methods are needed to observe and study subsurface and surface processes associated with the transport of geothermal fluid. Understanding in detail how the various components in the geothermal fluid affect the machinery encountered in the cycle is essential to avoid undesirable processes such as corrosion of parts of the machinery or clogging of injection wells by precipitation and deposition of minerals. The chemical composition and possible multiphase flow call for utmost care in the selection of materials and for an adjustment of process parameters in the apparatuses of the power plant (temperature and pressure). Innovative monitoring systems are needed to observe processes in real time and to allow for immediate reaction to changes in the system.