Theoretical Solution And Numerical Calculation Of Liquid Layer Acoustic Field In Horizontal Multilayer Solid And Porous Media

Propagation of the acoustic wave in layered media have been a hot problem which a lot of scholars were concerned. All geological media can be viewed as a layered media and the sedimentary rock usually have a layered structure. Many sedimentary rock are made up of the porous rock filled with water. Skeleton are made up of grain and suffered from the weight pressure of overlying cladding and a certain cementation together. Skeleton may include interconnected deliquescent channels and continuous pulse rocks with many boreholes. Or skeleton can be broken rock. The rock porosity was decided by the stagger of rocks. Though full of oil and gas in the borehole are limited, oil and gas exploration in the oil well logging have more important meaning.Acoustic logging generally find oil and gas deposits. Deposit's layers are almost slow velocity media at two fast velocity media with two phases. They are just the goal layers by cross borehole seism. Trough wave exploration, There is a low velocity layer, i.e. wave guide, two fast velocity layers in above various situations. Thus, it is important and significant to investigate the propagation of elastic wave in layered slow velocity medium. Therefore, in the layered elastic solid medium and porous media model, study of elastic waves in the multilayered media dissemination and application of oil exploration have more significant.Based on this require and former work (Wei Zhang 1995 year fluid between flexible solid and Ba Yin 2001 year fluid between Biot porous media), the horizontal multilayer media is a relatively simple three symmetric model in this paper, The porous media increased semi-infinite solid media up and down .Theoretical solution and numerical calculation is based on acoustic wave of horizontal liquid layer.Firstly, applying the model ,under the sound source excitation, on the basis of boundary conditions, we calculate the matrix elements of full wave sound pressure and the dispersion equation. Complex velocity method was used in the calculation of full wave sound pressure. Increasing the Q value of a medium so that the real axis integration can continue in the complex plane. As the horizontal multilayer, Fourier double integral in the wave number field from zero to infinity, So Romberg integral was used in the wave number field and frequency field used Fast Fourier Transform.Secondly , though three media is close to two media. The gained results have been compared with the old result (Bad Yin 2001 year). Feasibility of the method and the software. were tested The full wave of fluid layer acoustic field were researched at different center frequencies, different source distance and media parameters,. Both Biot media and solid media are hard media formation. Biot media and solid media are almost hard .seeing the P-wave, the S-wave, the mode wave, the Stoneley wave and the Airy phase. As the stratum hardness is very similar, it is difficult to distinguish P-wave and S-wave which strata radiated. Solid media is hard than the Biot media. We can see the P-wave of the solid media, the S-wave of the solid media, the mode wave, and the Stoneley wave. Solid media is soft than the Biot media. We can see the P-wave of the Biot media, the S-wave of the Biot media, the Stoneley wave and the Airy phase. Meanwhile seeing reservoir parameters (porosity and permeability) effect on the full waveFinally. using Newton iterative method for numerical simulation of dispersion equation. Analyzing the phase velocity, the group velocity and excitation intensity of the mode wave at a certain frequency range, then researching the first order mode wave with reservoir parameters (porosity and permeability) changes. Numerical calculation is showed: The dispersion characteristic is similar to columnar layered model of the borehole. But excitation is different and excitation is very sharp. Excitation curve is not monotonic decreased, but increased again with the increase of frequency.In conclusion, theory and numerical simulation of the fluid layer acoustic field have more understanding and cognition. To master multi-media propagation characteristics, we hope that it is important to identify and separate wave field of the multi-media in the practical work...