Simulation des Produktionsverhaltens gefracter Bohrungen in geringpermeablen Gaslagerstätten

Two main issues emerge in the case of modeling hydraulically fractured wells: (i) the simuiation of the clean-up period and (ii) the simulation of the long-term production behaviour. To investigate the two periods, field data from two wells in the North German Rotliegend formation are analysed. A commercial Black-Oil simulator is used in the study with different discretisation schemes. In the case of the first well the clean-up process was matched lasting several days. The match achieved an adequate approximation to the measured field values. The breakthrough time of gas as well as the gas and water production rates showed a good agreement. The case of the well 2 included a four year production period. The history match results were characterized by a good correspondence of measured and simulated well pressures. Within the framework of the investigations it turned out, that the geomechanical dependency on reservoir and fracture parameters on the effective stress as well as the saturation conditions and the gas-water functions for the tight sandstone are major factors of influence for fractured wells in low-permeability reservoirs.