海底冷泉气泡羽流地震波数值模拟

海底冷泉广泛分布于全球大陆边缘海域,是未来能源勘探的重要领域.本文根据海底冷泉羽流特征,设计多个典型2D冷泉气泡散射地球物理模型并观测其数值模拟的地震响应特征.冷泉正演模拟的关键是建立典型地震海底冷泉散射模型,本文首先构建了平稳随机散点模型,设计了符合实际的气泡半径和气泡体积分数的参数模型,通过参数填充和计算得到了等效速度模型.由此建立的模型在适应性和灵活度上凸显出很大优势,极大地提升了地震响应的可靠程度.单炮地震记录显示冷泉羽流区散射能量最强,地震波场散射清晰,散射波场沿冷泉延伸方向具有明显的方向性.复杂冷泉气泡散射模型的正演模拟结果表明地震响应能够准确描述海底冷泉羽流,对冷泉羽流的研究和寻找海洋天然气资源具有重要意义.

Numerical simulation of seismic waves of bubble plumes in submarine cold seepages

Submarine cold seepages are widely distributed natural phenomena in continental marginas of the world, which are important areas of energy exploration in the future. In this paper, several typical 2D geophysical models of bubble scattering from cold seepage plumes are designed and the seismic response characteristics of their numerical simulation are observed. The key of cold spring forward simulation is to establish a scattering model of typical seismic bubble plumes in submarine cold seepages. The geophysical model of bubble scattering in cold seepages can be divided into three steps:Firstly, the stationary random scattering model is constructed, and the parameter models of bubble radius and volume fraction are designed. Then the equivalent velocity model is obtained by filling and calculating the parameter models. The model has great advantages in adaptability and flexibility, and greatly improves the reliability of seismic response. The key of forward modeling of cold seepages is to establish a scattering model of typical seismic submarine cold seepages. The research shows that the scattering energy of the plume column region is the strongest, the scattering wavefield appears obviously disorder, and has obvious directionality along the extension direction of cold seepages. The scattering energy of the plume column region is the strongest. The numerical simulation results of a complex cold seepage bubble scattering model show that the seismic response can accurately describe the submarine cold seepage plume, which is of great significance to the study of cold seepage plume and the exploration of marine natural gas resources.