Quantifying Time-lapse Effects of Solution Squeeze Mining

SUMMARY In the northern part of The Netherlands the magnesium salts carnalite and bischofite are mined in a deep solution mine. For optimal production and also for environmental impact such as subsidence, it is vital to understand the process of salt production. To this aim, it is studied whether seismic in time-lapse mode may help to visualize and quantify the changes due to the salt production. The main questions addressed are: Can changes due to salt production be detected in seismic time-lapse mode? And if so, how big are these changes? To address these issues, a modelling study was performed. Seismic data were synthesized using acoustic and elastic finite-difference schemes, and further processed to obtain migrated seismic images. For the models themselves, different production scenarios were studied. Analysis of these data clearly shows that salt mining causes detectable changes in time-lapse seismic signals and can be quantified. The amplitude effect seems relatively larger than the induced time shift.