冷泉活动区气泡羽状流数值模型研究

羽状流对天然气水合物的识别起到了间接指示作用，为研究冷泉活动区气泡羽状流产生的地震响应，需建立符合实际羽状流特征的模型。为此，参考实际羽状流赋存状态，结合含气泡水体特征，在已建立模型基础上，从羽状流气泡的垂直运移规律、分布特点及羽状流外观特征上对模型进行了改进，先后获得3个羽状流模型，最后的模型Ⅲ更接近实际羽状流赋存特征。通过与实际羽状流的对比，讨论分析了模型Ⅲ的合理性，并得出结论：所建模型体现了实际羽状流气泡的本质特征，并包含了更为复杂的气泡含量变化，可用于进一步深入研究羽状流地震响应特征，也为气泡羽状流的地震识别及天然气水合物的相关研究提供了较好的数值模型。

STUDY ON NUMERICAL MODELS ABOUT BUBBLE PLUMES IN THE COLD SEEPAGE ACTIVE REGION

Bubble plume is an indirect indicator to gas hydrate. In order to study the seismic responses produced by bubble plumes in a cold seepage active region, a model well marching the characteristics of the actual plume needs to be established. Taking the actual occurrence of the bubble plume as a reference and taking bubble water characteristics into account, we improved the vertical distribution pattern of the plume bubbles and the appearance of plume for established models following the principles of vertical migration law. At last, three models are worked out. Testing shows that the Model Ⅲ is more accurate in presenting the actual occurrence characteristics of the plume rather than the Model Ⅰ and Model Ⅱ. Rational discussion is made by comparing the model with the real plume. And it is concluded that the model established well reflects the essential characteristics of the bubbles in plume, and contains more complex changes in bubble content. Therefore, it can be used to further study the seismic response characteristics of plume, and make it possible to identify bubble plumes for research and evaluation of natural gas hydrate deposits.