System Integration of Various Geophysical Measurements for Reservoir Monitoring

Since 2002, we have been carrying out a cooperative research program entitled “System Integration of Various Geophysical Measurements for Reservoir Monitoring”; involving both the Okuaizu and Ogiri geothermal fields in Japan. This continuing work carries forward a completed 1997-2002 NEDO/GSJ project on the application of various geophysical survey techniques to reservoir monitoring and modeling. To appraise the utility of reservoir monitoring by simultaneous continuous/repeat measurements of gravity, SP and electrical resistivity for history-matching of reservoir models, we performed numerical simulations based upon two types of hypothetical reservoir models and calculated changes in these geophysical observables on the ground surface caused by changing reservoir conditions. On the basis of these calculations, we discuss a combination of multi-geophysical measurements which can provide useful additional constraints for history-matching studies.