贝叶斯的NMR石质物理特征化贝叶斯的NMR石质物理特征化
1Victoria University of Wellington, Wellington, New Zealand.
Journal of magnetic resonance (San Diego, Calif. : 1997)
|April 10, 2024
概括
一种新的贝叶斯方法改善了核磁共振 (NMR) 对水库岩石的数据分析. 这种技术增强了孔径分布和石化物理性质的估计,这对于石油和天然气勘探至关重要.
科学领域:
- 地质科学和石化物理学
- 数据分析和估计方法 数据分析和估计方法
背景情况:
- 在石油和天然气勘探和回收方面,水库岩石类型的识别至关重要.
- 诸如孔隙性和透性之类的石化物理性质是水库建模和生产规划的关键.
- 核磁共振 (NMR) 技术提供了快速而准确的石化物理特征.
研究的目的:
- 引入和评估用于分析NMR T2分布的贝叶斯估计方法.
- 为了利用T2分布的先前知识来改进石化物理属性估计.
- 将贝叶斯方法与现有的储岩石表征技术进行比较.
主要方法:
- 开发了一种贝叶斯估计方法,结合T2分布的先前信息 (平均值和共变量).
- 从合成的T2分布中使用模拟的NMR衰变数据评估了该方法.
- 对T2LM和RMSE的性能比较,使用孔隙度,结合流体体积 (BFV) 和T2分布精度.
主要成果:
- 与现有方法相比,贝叶斯估计器在估计T2分布方面表现优异.
- 贝叶斯的方法在获得的石质物理性质上优于ILT方法,除了在特定的低噪音,短时间的放松条件下.
- 使用实验T2分布的验证证实了贝叶斯方法的有效性.
结论:
- 拟议的贝叶斯方法提供了一个强大而准确的方法来分析NMR数据在水库表征.
- 纳入先前的知识显著提高了从NMR T2分布的石质特性估计.
- 这种方法对于改进水库建模和优化石油和天然气回收策略非常有价值.
相关概念视频
01:20¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)
1.0K
When proton-coupled carbon-13 spectra are simplified by a broadband proton decoupling technique, structural information about the coupled protons is lost. Distortionless enhancement by polarization transfer (DEPT) is a technique that provides information on the number of hydrogens attached to each carbon in a molecule. While the DEPT experiment utilizes complex pulse sequences, the pulse delay and flip angle are specifically manipulated. The resulting signals have different phases depending on...
1.0K
00:58¹H NMR Signal Integration: Overview
1.4K
The intensity of a signal, which can be represented by the area under the peak, depends on the number of protons contributing to that signal. The area under each peak is shown as a vertical line called an integral, with the integral value listed under it, as seen in the proton NMR spectrum of benzyl acetate. Each integral value is divided by the smallest integral value to obtain the ratio of the number of protons producing each signal. The ratio reveals the relative number of protons and not...
1.4K
01:02¹H NMR: Interpreting Distorted and Overlapping Signals
1.0K
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
1.0K
01:14NMR Spectroscopy of Aromatic Compounds
4.7K
Aromatic compounds can be identified or analyzed using proton NMR and carbon‐13 NMR. Typically, aromatic hydrogens or hydrogens directly bonded to the aromatic rings are strongly deshielded by the aromatic ring current. Therefore, they absorb in the range of 6.5–8.0 ppm in proton NMR spectra. For instance, aromatic hydrogens directly bonded to the benzene ring absorb at 7.3 ppm. However, aromatic hydrogens of larger rings absorb farther upfield or downfield than the ideal range.
4.7K
01:10Interpreting ¹H NMR Signal Splitting: The (n + 1) Rule
1.3K
In the AX proton spin system, proton A can sense the two spin states of a coupled proton X, resulting in a doublet NMR signal with two peaks of equal (1:1) intensity. When proton A is coupled to two equivalent protons (AX2 spin system), the spin states of each X can be aligned with or against the external field, creating three possible scenarios. This results in a 1:2:1 triplet signal, where the central peak corresponds to the chemical shift of A and is twice as large or intense as the...
1.3K
01:13¹H NMR: Complex Splitting
1.3K
A proton M that is coupled to a proton X results in doublet signals for M. However, NMR-active nuclei can be simultaneously coupled to more than one nonequivalent nucleus. When M is coupled to a second proton A, such as in styrene oxide, each peak in the doublet is split into another doublet.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
1.3K