HEAT EXTRACTION MODELING FROM FORCED FLUID-FLOW THROUGH STIMULATED FRACTURED ROCK MASSES - APPLICATION TO THE ROSEMANOWES HOT DRY ROCK RESERVOIR

A series of modelling tools have been developed for fractured media, w here the problem of connectivity is the major mechanism governing flow , and mass or heat transport. These are boolean models, where randomly distributed fractures are generated in space. Flow and transport prop erties are then distributed at a local scale for calculating global hy draulic and dispersive behaviour. Ensembles of realisations are genera lly generated, but are difficult to condition on measurements. Based o n the experimental results obtained at great depth (c. 2.5km) at the R osemanowes HDR site (Cornwall, UK), this approach is shown to be appro priate for most of the available data. These data are integrated in a single model and used to produce relevant estimates for the main hydra ulic parameters. Flow through stimulated fracture networks is then inv estigated and the thermal behaviour of the simulated geothermal loops is derived. The discussion focuses on thermal drawdown with elapsed ti me and demonstrates the high probability of having preferential flow c onnections (short circuits) between the boreholes.