| 天然气水合物赋存地层的地震波场模拟及对比 |
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| 引用本文： | 范金,刘洋廷,张晓波,刘凯,郑彦鹏.天然气水合物赋存地层的地震波场模拟及对比[J].海洋科学进展,2021,39(2):290-303. |
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| 作者姓名： | 范金 刘洋廷 张晓波 刘凯 郑彦鹏 |
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| 作者单位： | 自然资源部 第一海洋研究所,山东 青岛 266061;青岛海洋科学与技术试点国家实验室 海洋地质过程与环境功能实验室,山东 青岛 266237;青岛海洋科学与技术试点国家实验室 海洋地质过程与环境功能实验室,山东 青岛 266237;国家深海基地管理中心,山东 青岛 266237 |
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| 基金项目： | 国家重点研发计划项目——南海多类型天然气水合物成藏原理与开采基础研究(2017YFC0307302);中央级公益性科研院所基本科研业务费专项资金资助项目——黏弹性海底沉积物的AVO响应及物性反演方法研究(2018Q02);泰山学者工程专项经费项目(TSPD20161007);国家自然科学基金委员会-山东省人民政府联合基金项目——海洋地质过程与环境(U1606401);国家自然科学基金青年基金项目——基于柔性边界模型的南海北部陆坡峡谷区海底滑动运动定量研究(41606084)。 |
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| 摘 要： | 通过分析天然气水合物在海洋中的6种主要赋存状态类型,总结了每种赋存状态之间的相互转化关系及其物性参数计算方法,并应用到地震波场的正演模拟中。对比研究了声波模型、弹性波模型和双相介质模型对各种水合物赋存地层的响应特征,结果表明:1)当地层中存在孔隙充填型水合物且下伏地层不含游离气时,双相介质模拟的含水合物层底界表现负极性特征;当充填结核型水合物时,弹性介质和双相介质模拟的水合物底界反射呈负极性;2)当地层充填颗粒包裹型水合物且下伏地层含游离气时,无论是低频(25 Hz)条件还是提高子波主频(40 Hz),3种介质模拟水合物的地震响应特征都很明显,但水合物层底界反射振幅随偏移距变化的关系存在差异;3)当沉积薄层中充填颗粒间胶结型水合物且下伏地层含游离气时,弹性介质和双相介质模拟水合物薄层底界的反射振幅随偏移距的增大而减小;将水合物类型改为颗粒支撑型并提高子波主频,声波介质和弹性介质模拟水合物层底界的反射振幅随偏移距的增大而减小。
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| 关 键 词： | 水合物 赋存状态 正演模型 波场模拟 对比分析 |
Simulation and Comparison of Seismic Wave Fields in Natural Gas Hydrate Formations |
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| FAN Jin,LIU Yang-ting,ZHANG Xiao-bo,LIU Kai,ZHENG Yan-peng.Simulation and Comparison of Seismic Wave Fields in Natural Gas Hydrate Formations[J].Advances in Marine Science,2021,39(2):290-303. |
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| Authors: | FAN Jin LIU Yang-ting ZHANG Xiao-bo LIU Kai ZHENG Yan-peng |
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| Institution: | (First Institute of Oceanography,MNR,Qingdao 266061,China;Laboratory for Marine Geology and Environment,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,China;National Deep Sea Center,Qingdao 266237,China) |
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| Abstract: | This study summarizes the six major types of occurrence states of natural gas hydrates in the ocean.The mutual conversion relationship between each occurrence state and the calculation method of its physical parameters are applied to the forward modeling of the seismic wave field.The response characteristics of acoustic model,elastic wave model and biphasic medium model to various hydrate-bearing formations are comparably studied.The numerical simulation results show that:1)when there are pore-filled hydrates in the formation and the underlying formation contains no free gas,unlike the acoustic wave model and the elastic wave model,the two-phase medium simulates the bottom boundary of the hydrate layer and exhibits negative polarity characteristics;When filled with nodule hydrate,unlike the acoustic wave model,the elastic medium and the two-phase medium simulate the bottom reflection of the hydrate to be negative.2)when the ground is filled with particle-encapsulated hydrates and underlying free gas,the seismic response characteristics of the three media simulated hydrates are very obvious whether it is low frequency(25 Hz)or increasing the main frequency of the wavelet(40 Hz).However,there is a difference in the relationship between the reflection amplitude of the bottom boundary of the hydrate layer and the offset.3)when the deposited thin layer is filled with inter-particle cemented hydrate and underlying free gas,as the offset increases,the reflection amplitude of the elastic medium and the two-phase medium simulated hydrate thin layer bottom gradually decreases;By changing the hydrate type to particle-supported and increasing the main frequency of the wavelet,as the offset increases,the reflection amplitude of the bottom boundary of the simulated hydrate layer of the acoustic and elastic medium gradually decreases. |
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| Keywords: | hydrate occurrence state forward model wave field simulation comparison and analysis |
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