非均质储层孔隙结构特征及流体分布尺度与地震波速度频散关系研究

低频条件下地震波速度频散制约了地震油气勘探理论的发展。地震波速度频散机理复杂，前人已提出多种速度频散理论模型，但在速度频散的机理及其关键影响因素等基本问题上尚未形成普适的科学结论。根据前人及课题组前期工作，本课题假设：低频条件下孔隙流体压力变化是产生速度频散的主要原因，而岩石孔隙结构特征与流体分布尺度是控制孔隙流体压力平衡的决定性因素。课题组将开展岩石孔隙结构特征、孔隙流体运动及其分布尺度与速度频散的特征频率关系研究，确定不同孔隙特征及流体分布尺度与速度频散的理论关系，实验验证地震波速度频散的主控因素，建立广义孔隙特征及流体分布尺度参数与速度频散松弛时间理论模型。课题创新之处是将岩石孔隙结构特征及流体分布尺度引入到衰减特征频率理论模型中，并采用应力-应变实验方法直接在低频范围进行速度频散的机理分析与理论验证。本项研究将建立地震波速度频散理论新模型，有力地提升我国油气资源勘探开发的理论水平。

Seismic velocity dispersion is an important factor in the development of oil and gas seismic exploration theory. The mechanism of seismic velocity dispersion is complex. Many dispersion theoretical model has been established. But a universal scientific conclusion about the mechanism of seismic velocity dispersion and its key factors is not yet made. Based on the results of previous studies and our group work, The hypothesis can get is that the changes in pore fluid pressure in the low frequency is the main reasons to induce seismic velocity dispersion, and pore structure characteristics and fluid distribution scale is the decisive factors that control the fluid pressure equilibrium. This application plan to carry out the study of the relationships among pore structures, fluid movement and its distribution scale and the characteristics frequency of seismic velocity dispersion, determine the theoretical link between different pore characteristics, fluid distribution scale and velocity dispersion, establish a new dispersion theoretical model. The different with the previous work is that the pore characteristics and fluid distribution scale will be introduced into the characteristic frequency equation, the low-frequency measurement system will be firstly used to verify and theoretically analyze the seismic velocity dispersion result directly measured in the low-frequency range. By this study, a new theoretical model of seismic velocity dispersion will be established，which will greatly enhance the level of the theory of China's oil and gas exploration and development.