Study On Wavefield Numerical Simulation Of Viscoelastic-porous Media

With the rapid development of petroleum geophysical prospecting, seismic oil and gas exploration target also gradually to the complex structural reservoir and lithologic reservoir, fracture reservoir development. It has been found that the traditional reservoir identification technology is difficult to meet the requirements of reservoir fluid identification, underground reservoir, especially the oil-gas reservoir, the regular contain different attributes in the pore fluid, although the theory of anisotropic medium of perfecting and developing for a long time, but it also found that build the acoustic theory and the theory of elastic wave is unable to reasonably explain the seismic wave in underground media spread of seismic wave is in the process of absorption, dispersion and attenuation of the phenomenon.Gassman equation is an important equation of porous medium theory, Biot theory in Gassman equation from the macroscopic point of view on the basis of the characteristics of solid phase and underground media flow, gives a study of the basic theory of porous media seismic wave propagation law. Micro Squirt jet flow theory are explained from the microscopic view seismic wave in the process of underground transmission attenuation of high frequency dispersion and high phenomenon, proves that the microscopic mechanism of fluid flow is the main cause of the high seismic waves of high frequency dispersion and attenuation. And combines the Biot flow mechanism and the Squirt flow mechanism of BISQ model, although after the improvement of the long-term and simplified calculation efficiency improved, model calculation formula has been simplified, but there are still two prominent problems difficult to solve. Is a model to simulate the attenuation of high frequency band, severely limits the model and the theory of the popularization and application in practical work. Secondly, the underground medium causes of three kinds of seismic wave wavelength conversion mechanism including porosity, viscoelasticity and anisotropic. Traditional BISQ model only considers the two aspects of porosity and anisotropy of factors, not the underground medium viscoelasticity into the theoretical model, the characteristics of good fusion greatly limits the development of the theory.This article fully considering the characteristics of viscoelastic, described the generalized zener linear body medium sticky bombs nature theory of bipolar anisotropic medium theory is introduced, the establishment of a unified sticky elastic anisotropic porous media model. The sticky bombs framework based on spectral relaxation mechanism, is applicable to numerical simulation in time domain. This article USES the high order staggered grid finite difference method is applicable to time domain numerical simulation of the stress equation of first order rate forward modeling, and use memory variables to avoid the convolution operation in sticky elastic skeleton mechanism. By comparing different difference order of wavelength snapshot, I find the most suitable for the model of numerical simulation of finite difference order. By and sticky bombs pore model of completely elastic porous medium model simulation results related to the wavelength snapshot, seismic synthetic record contrast observation, can clear quickly P wave and shear wave attenuation phenomenon in seismic frequency band, and porous sticky bombs model in simulating the real reservoir, seismic wave dispersion and attenuation phenomenon has good behaviors like traditional porous elastic model.