Quantitative measurement of two-dimensional distribution functions of diffusion and relaxation in grossly inhomogeneous fields
Quantitative measurement of two-dimensional distribution functions of diffusion and relaxation in grossly inhomogeneous fields
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DOI：
10.1006/jmre.2002.2567
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发表时间：
2002-07-01
影响因子：
2.2
通讯作者：
Venkataramanan, L
中科院分区：
文献类型：
--
作者：
Hürlimann, MD;Venkataramanan, L
我们演示了在极不均匀的场存在的情况下多维分布函数的定量提取。给出了扩散T-2分布函数和T-1-T-2分布函数的算例。脉冲序列由初始编辑序列和随后的长系列标称180个脉冲组成。它们被设计成使得描述分布函数和测量数据之间的关系的核是可分离的。讨论了所需的相位循环。我们详细分析了由强场不均匀性引起的额外自旋动力学效应，包括对扩散和弛豫的影响。一种最新开发的算法被用来以有效的方式反演数据并提取稳定的多维分布函数。我们给出了这项新技术的几个应用实例。扩散-松弛分布函数可用于流体识别和基于受限扩散效应的多孔介质孔隙几何特征的表征。我们还确定了水饱和沉积岩的T-1-T-2分布函数，并发现与以前在均质油田中进行的测量结果非常一致。(C)2002年埃尔塞维尔科学公司(美国)。
We demonstrate the quantitative extraction of multidimensional distribution functions in the presence of grossly inhomogeneous fields. Examples are shown for diffusion-T-2 distribution functions and T-1 - T-2 distribution functions. The pulse sequences consist of an initial editing sequence followed by a long series of nominal 180 pulses. They are designed such that the kernels describing the relationships between the distribution functions and the measured data are separable. The required phase cycling is discussed. We analyze in detail the extra spin dynamics effects due to the strong field inhomogeneities including the effects on diffusion and relaxation. A recently developed algorithm is used to invert the data and extract stable multidimensional distribution functions in an efficient manner. We present examples for several applications of this new technique. Diffusion-relaxation distribution functions can be used for fluid identification and for the characterization of pore geometry of porous media based on the effects of restricted diffusion. We have also determined T-1 - T-2 distribution functions of water saturated sedimentary rock and find excellent agreement with previous measurements performed in homogeneous fields.(C) 2002 Elsevier Science (USA).