水合物核磁共振响应特征实验研究  

Experimental research on NMR response characteristics of hydrates

作　　者：汤克轩 李振宇[2] 王弘宇 张文波[2] 潘剑伟 TANG Kexuan;LI Zhenyu;WANG Hongyu;ZHANG Wenbo;PAN Jianwei(China Water Resources Beifang Investigation,Design and Research Co.,Ltd.(BIDR),Tianjin 300222,China;Institute of Geophysics&Geomatics,China University of Geosciences(Wuhan),Wuhan,Hubei 430074,China;Hubei Earthquake Agency,Wuhan,Hubei 430071,China;College of Resources and Environmental Engineering,Guizhou University,Guiyang,Guizhou 550025,China)

机构地区：[1]中水北方勘测设计研究有限责任公司,天津300222 [2]中国地质大学(武汉)地球物理与空间信息学院,湖北武汉430074 [3]湖北省地震局,湖北武汉430071 [4]贵州大学资源与环境工程学院,贵州贵阳550025

出　　处：《石油地球物理勘探》2021年第4期910-921,I0016,共13页Oil Geophysical Prospecting

基　　金：中国地质调查局科技外事部项目“陆域天然气水合物勘查技术研究与集成——祁连山木里地区冻土带天然气水合物SNMR探测方法研究”(GZHL20110324)资助。

摘　　要：研究冻土区天然气水合物核磁共振(NMR)响应特征对冻土层结构划分及水合物储层识别具有重要意义。为此,设计实验研究了四丁基溴化铵(TBAB)水合物形成和分解过程中实验样本的NMR信号变化规律,为天然气水合物研究提供参考。实验数据表明,水合物样本冻融过程中NMR信号横向弛豫(T2)时间谱含三个明显波峰,即主峰、次峰、附峰,分别源于自由水、结合水及水溶有机质中的H核。波峰的分布、幅值、面积及变化规律,可作为研究水合物样本物化态变化过程的依据,尤其是次峰和附峰的显著程度是判断水合物存在及表征其含量的直接证据。将TBAB水合物的分解过程分为分散期、分解期和稳定期三个阶段,推导建立了水合物样本NMR信号与温度、时间的关系式,可作为定量分析水合物含量和存储条件的依据。Studying the nuclear magnetic resonance(NMR)response characteristics of gas hydrate in frozen soil region is of great significance for the classification of permafrost structure and the identification of hydrate reservoir.This study explores the NMR signal variation characteristics of the test samples during the formation and decomposition of tetrabutylammonium bromide(TBAB)hydrate.There are three obvious peaks(main peak,secondary peak and attached peak)in the transverse relaxation(T2)time spectrum during freeze-thaw of the hydrate,which are attributed to the H nuclei of free water,bound water and water-soluble organic matter,respectively.Utilizing the distribution,amplitudes,areas and their variation of peaks,we can study the physicochemical state change of hydrate samples.In particular,the significance of the secondary peak and the attached peak can be employed to directly judge whether the hydrate exists and clarify its content.The decomposition of TBAB hydrate is divided into three stages:dispersion stage,decomposition stage and stable stage.Also,the relations of NMR signals with temperature and time are derived,which are applicable as the basis for the quantitative analysis of the content and storage conditions of the hydrate.

关 键 词：核磁共振 天然气水合物 四丁基溴化铵 物性实验 温度 

分 类 号：P631[天文地球—地质矿产勘探]