饱和Maxwell流体孔隙介质波传播模型研究

Study on wave propagation model for Maxwell-fluid-saturated porous media

岩石中的弹性波传播特性研究一直是地球物理学研究中的基础科学问题和难点.Biot理论的提出为流固双相介质理论奠定了基础.Biot理论中假设固相、液相的本构关系是线弹性的.而当实际储层中含高黏度的流体时,流体往往表现出一定的非牛顿流体性质.本文主要针对含高黏度流体的孔隙介质,在Biot理论模型中引入线性黏弹性的Maxwell流体本构方程.要通过动态黏度入手,表征非牛顿流体的特性,改进并给出了含高黏度孔隙流体介质的模型.通过数值模拟分析了所提出的模型的特性,并分析了初始黏度和孔隙度参数对模型数值分析结果的影响.最后选取超声波实验数据验证了模型的适用性,结果表明该理论模型的预测结果可较好地反映含高黏度流体孔隙介质的波传播特性.

The study of elastic wave propagation characteristics in rocks has always been a basic scientific problem and difficult subject in geophysics. The Biot theory laid the foundation for the fluid-solid two-phase medium theory. Biot theory assumes that the constitutive relation between the solid and liquid phase is linear elastic. When the reservoir contains high-viscosity fluids, the fluids often exhibit certain non-Newtonian fluid properties. This study focuses on porous media containing high-viscosity fluid, and introduces linear viscoelastic Maxwell fluid constitutive equations into the Biot theoretical model. We mainly start with dynamic viscosity to reveal the characteristics of non-Newtonian fluids, reformulate and give a model of high-viscosity fluid-saturated porous media. Analysis of the characteristics of the proposed model through numerical simulations is performed, and the effect of initial viscosity and porosity parameters of the numerical model results are analyzed. Finally, ultrasonic experimental data is used to validate the applicability of the proposed model. The results show that the predictions of the theoretical model can well describe the wave propagation characteristics in a porous media containing high-viscosity fluid.