【摘要】：近年來,針對天然氣水合物的調(diào)查研究及勘探開發(fā)進展迅速。大量觀測結(jié)果表明,海水中的甲烷氣泡羽流與海底天然氣水合物礦藏密切相關(guān)。研究氣泡羽流,對尋找水合物的賦存區(qū)域、了解水合物的成藏機制和成藏環(huán)境等均有重要意義。地震方法在水合物相關(guān)的研究中,具有無可替代的優(yōu)越性。為了明確水合物氣泡羽流的地震響應(yīng)特征,獲知其地震波能量與氣泡參數(shù)的定量關(guān)系,以期為實測氣泡羽流地震資料偏移成像速度分析提供理論依據(jù),本文開展了針對三維氣泡羽流的建模及其波場數(shù)值模擬與地震響應(yīng)特征研究。具體包括:①在前人工作的基礎(chǔ)上,總結(jié)和分析了氣泡羽流在水體中的運移規(guī)律與各項參數(shù)的變化范圍,采用背景參數(shù)與隨機擾動參數(shù)疊加的方式構(gòu)建氣泡羽流參數(shù)模型,利用姚文葦?shù)忍岢龅墓接嬎銡馀萦鹆鞯乃俣?在Fortran和Matlab平臺下編寫了實現(xiàn)程序,建立了氣泡含量變化的氣泡羽流的三維模型系列。②通過反復(fù)試驗,設(shè)計了較為合理的觀測系統(tǒng)和采集參數(shù),實現(xiàn)了氣泡羽流的波場數(shù)值模擬。③利用疊前深度偏移剖面,采用屬性分析方法分別研究了深度方向上和同一深度處模型系列中的地震波均方根振幅與氣泡含量的定性和定量關(guān)系。以上研究表明:均方根振幅與氣泡含量間的關(guān)系復(fù)雜,不是簡單的線性關(guān)系。在所研究的氣泡含量區(qū)間內(nèi),當(dāng)氣泡含量小于4.5*10-5時(體積分數(shù)),均方根振幅隨氣泡含量的增加而增大;氣泡含量位于4.5*10-5到1.05*10-4范圍內(nèi)時,均方根振幅隨氣泡含量增加而減小;氣泡含量大于1.05*10-4時,均方根振幅又隨氣泡含量的增加而增大。這種變化規(guī)律可能與氣泡羽流隨機擾動幅度變化有關(guān),尚待后續(xù)研究證實。本文的研究成果為水合物氣泡羽流成像速度研究提供了理論依據(jù),也為后續(xù)基于巖石物理模型的水合物氣泡羽流相關(guān)研究奠定了基礎(chǔ)。
[Abstract]:In recent years, the investigation and exploration and development of natural gas hydrate have made rapid progress. A large number of observations show that the methane bubble plume in seawater is closely related to the marine gas hydrate deposits. The study of bubble plume is of great significance in finding the region where hydrate occurs and in understanding the mechanism and environment of hydrate formation. Seismic method has irreplaceable advantages in hydrate related research. In order to clarify the seismic response characteristics of gas hydrate bubble plume and obtain the quantitative relationship between seismic wave energy and bubble parameters, this paper provides a theoretical basis for the analysis of migration imaging velocity of measured bubble plume seismic data. In this paper, the modeling of three dimensional bubble plume, the numerical simulation of wave field and the characteristics of seismic response are carried out. The main contents are as follows: 1 on the basis of previous work, this paper summarizes and analyzes the migration law of bubble plume in water body and the variation range of each parameter, and constructs the bubble plume parameter model by the superposition of background parameter and random disturbance parameter. Using the formula proposed by Yao Wenwei and others to calculate the velocity of bubble plume, a program is compiled under the platform of Fortran and Matlab, and a series of three-dimensional models of bubble plume with varying bubble content are established. 2 through repeated experiments, A more reasonable observation system and acquisition parameters are designed, and the wave field numerical simulation of bubble plume is realized. 3 using prestack depth migration profile, The qualitative and quantitative relationships between the root-mean-square amplitude of seismic waves and bubble content in the depth direction and at the same depth are studied by means of attribute analysis. The above results show that the relationship between root-mean-square amplitude and bubble content is complex and is not a simple linear relationship. The root-mean-square amplitude increases with the increase of bubble content when the bubble content is less than 4.5 渭 10-5 (volume fraction). The root-mean-square amplitude decreases with the increase of bubble content when the bubble content is within the range of 4.5 ~ 10 ~ (-5) to 1.0 ~ (-5) ~ 10 ~ (-4), and increases with the increase of bubble content when the bubble content is greater than 1.05 脳 10 ~ (-4). This rule may be related to the variation of the random disturbance amplitude of the bubble plume, which needs to be confirmed by further studies. The results of this paper provide a theoretical basis for the study of gas hydrate bubble plume imaging velocity, and also lay a foundation for the subsequent research on gas hydrate bubble plume correlation based on rock physical model.
【學(xué)位授予單位】：中國地質(zhì)大學(xué)(北京)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P631.4;P618.13

【參考文獻】

相關(guān)期刊論文 前2條

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本文編號：2344209