Study On Propagation Characteristics Of Seismoelectric Waves Based On BISQ Model

The study on the seismoelectric effect is of significant importance in revealing seismoelectric exploration and acoustic-electrical logging mechanism,but the current Pride seismoelectric theory cannot accurately predict the coupling and dispersion characteristics of seismoelectric wave,which restricted the promotion and application of seismoelectric methods in exploration and development of oil and gas fields.Based on the BISQ model containing Biot flow and injection flow mechanisms,and combined with capillary model of seepage field and current field coupling theory,the Pride theory was modified.Then we quantitatively simulated the propagation characteristics of coupled seismoelectric wave and perform quantitative analysis of the impact of reservoir parameters on seismoelectric wave propagation.This reveals seismoelectric coupling mechanism theory in the saturated reservoir.Firstly,based on the BISQ model of porous media,the seepage field and current field coupling theory in the capillary model are combined with Maxwell's electromagnetic theory.The Pride coupling theory was also modified to construct a mathematical model based on BISQ model in saturated reservoir.The propagation properties of 2D seismoelectric wave field in saturated reservoir is quantitatively simulated and the effect of reservoir petrophysical parameters and electrochemical parameters on seismoelectric effect in saturated reservoir is also simulated.Then,the study of seismoelectric effect is expanded to its reverse process that is electron-seismic effect.We use the method of establishing seismoelectric effect model based on BISQ in saturated reservoir and combine the BISQ theory with porous medium seepage field,current field and Maxwell's electromagnetic theory to build a one-dimensional harmonic alternating current field with excitation equation of elastic wave field and calculate seismoelectric-elastic wave velocity in solid phase as well as the frequency variation in seepage field.Finally,we use the coupling relationship established by previous studies between the stable seepage field,current filed and ion flow field and combine the jet flow theory to determine the mathematical method of quantifying the seismoelectric effect based on the hydrological properties and chemical-electrical properties of reservoir rocks.This can be used to quantify the effect of flow electrical potential and electroosmotic flow and will provide theoretical foundation for the elastic wave theory of seismoelectric effect study in saturated reservoir.