USEFULNESS OF SENSITIVITY ANALYSIS FOR FEASIBILITY STUDIES OF TIME-LAPSE SEISMIC MONITORING

摘要

Here, we discuss the sensitivity of the seismic response to uncertainties in the physical parameters of the reservoir rock. A sensitivity analysis of Gassmann fluid substitution equations using a Monte Carlo approach is carried out. For this purpose, we represented uncertainties related to each parameter as probability density functions. Therefore, we evaluate the contribution of each parameter uncertainty to the variance of the seismic response (Vp), by means of Monte Carlo calculations. We also evaluated the contribution of possible variations in fluid phase density and bulk modulus, as well as of a pore pressure perturbation (4MPa) for several scenarios of connate and injection fluids on the variance of Vp. We did this for several values of initial differential pressure.