煤中水可动性的核磁共振响应及其影响因素  

Nuclear Magnetic Resonance (NMR) Response of Mobile Water in Coals and Influencing Factors

作　　者：吕玉民[1] 胡爱梅[2] 汤达祯[1] 宋波[2] 梁为[2] 许浩[1] 林文姬[2] 胡雄[2] 

机构地区：[1]中国地质大学(北京)煤储层实验室,北京100083 [2]中联煤层气国家工程研究中心,北京100095

出　　处：《高校地质学报》2012年第3期549-552,共4页Geological Journal of China Universities

基　　金：国家重点基础研究发展计划(902009CB219604);国家科技重大专项(2011ZX05038-001);中央高校基本科研业务费(2011PY0211)

摘　　要：依托韩城地区主要煤层，开展了饱和水煤岩在两种不同离心速率下离心1．5h后的核磁共振实验。同时，结合称重测煤芯饱和度的方法，分析了不同离心速率下煤岩内部可动流体和束缚流体的消长关系。实验表明，离心速率增大，煤岩核磁整体信号衰减，横向弛豫时间（T2）的几何均值和截止值逐渐下降。与饱和水煤岩相比，2000r／min速率离心后的煤岩咒谱强度下降5．14％～52．39％，几何均值下降24．72％。71．22％；4000r／min速率离心后的煤岩疋谱强度下降49．51％～63．36％，几何均值下降44．69％～81．59％；T2截止值下降44．09％～74．30％。研究发现，离心前后煤岩内部残留水量变化率与疋谱累计强度变化率具有很好的一致性，但与几何均值之间的相关性明显较差。分析认为，离心速率和孔渗特征共同决定煤层水可动性的NMR响应。Taking a case of major coal seams in the Hancheng area, the nuclear magnetic resonance （ NMR ） responses of water- saturated coal samples were measured at two centrifugal rates for 1.5 hours. Weight-saturation method was applied to analyze the relationship between saturations of mobile and bound fluids at various centrifugal rates. It was shown that the NMR signal of coal samples weakens and geometric mean and cutoff value of the transverse relaxation time （ /＇2 ） descend as the centrifugal rate increases. Compared with water-saturated coal samples, the /＇2 spectrum intensity of coal samples centrifuged at 2000r/min reduces by 5.14% to 52.39% and the geometric mean decreases by 24.72% to 71.22%, the T2 spectrum intensity of coal samples at 4000 r/min reduces by 49.51% to 63.36% and the geometric mean decreases by 44.69% to 81.59%, and the cutoff value of T2 spectrum drops by 44.09% to 74.30%. It was found that the change rate of residue water amount in centrifuged coal samples has a good saggesfed with the change rate of NMR accumulative intensity, but has a poor relationship with the change rate of cutoff value. It was suggested that the NMR response of mobile water in coal is controlled jointly by the centrifugal rate and porosity- permeability of coals.

关 键 词：煤 束缚水 可动性 离心 核磁共振响应 

分 类 号：P618.11[天文地球—矿床学]