| The seismic-electric effect,in essence,is the transformation between mechanical energy and electromagnetic energy. In many industry sectors, the seismic-electric effect has widespread and the actual use. Because seismic-electric effect is relative with the underground porous media double electric layer, in addition, the seismic-electric effect is relative with reservoir accumulation medium's porosity, permeability, fluid nature, thus we can differentiate the oil, the gas, the water material ingredient through the seismic-electric effect. The domestic and overseas researches showed the importance and the possibility of seismic-electric exploration from the theory and the scene experimentThe phenomenon of the elastic waves coupled with the electromagnetic waves in porous media is seismic-electric effects. It is peculiar phenomenon, and recently becomes more interesting research field in porous acoustics. Pride's governing equations describe such seismic-electric phenomenon. This text is begin with Pride coupling elastic waves-electromagnetic waves equation, deduce the numerical formulation of acoustic and electromagnetic field in and out borehole ,when plane SV-wave obliquely incident upon a well ,and coupling to the borehole。Then we utilize the acoustics and electromagnetic boundary conditions at interface of between porous formation and fluid medium to confirm the coefficient of each field, and solve the theoretical expressions. At last, we simulated field'response curve.The elastic formation is an ideal circs, the result is not satisfied to the practical need. In actually acoustic logging, the Biot porous media is more important. In this situation, this text advises that out well porous media is both hard formation and soft formation. This text is compared with literature [6], we find that in both hard formation and soft formation, seismic-electric effect has little effect to liquid pressure in a hole. For hard formation whenΦ0 is 10?1 1, round the axis of the borehole, one can receive 10 mv/m electric field and 10?1 2 A/m magnetic field. High frequency appeared a series of formant. It is because that liquid in well happens radial resonance. At frequency is 9 kHz appears the first formant, at 17 kHz appears the secondly formant. For soft formation, round axes have mv/m electric field and 10?1 3 A/m magnetic field. When incident angle is 15°,30°and 45°, at 8kHz, electric field has a wave crest. When incident angle is 90°, swing is 0, electric (magnetic) field does not produce resonance. When incident angle is 60°and 75°,and frequency is less than 5kHz, electric(magnetic) field is 0. Electric (magnetic) field has a series of wave crest as the frequency's augment. When incident angle is 75°,the wave crest is acute。Because permeability,porosity and mineralization are important for the exploitation of oil. So this text analyzes importantly these parameters affect to electric (magnetic) inside well and outside well. For the hard formation,The porosity and the mineralization's influences to the electromagnetic field are very big, under the identical frequency, the amplitude of electromagnetic field reduces as the porosity reduces, reduces along with the mineralization increases. The influence of permeability to electromagnetic field inside well is very small, but to electromagnetic field outside well is very big, under the identical frequency, the electromagnetic field′s amplitude reduces as the permeability increases. For the soft formation,under the identical frequency, the electromagnetic field′s amplitude reduces as the porosity reduces, reduces along with the permeability increases. The influence of mineralization to electromagnetic field inside well is very small. Electric field outside well reduces as the porosity reduces, reduces along with the mineralization increases. Therefore we find the conclusion that it is not feasible to use the electric field to calculate the permeability in the hard formation,but for soft formation, that is feasible.
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