论文标题
纳米融合对MD模拟和测量的动源中NMR松弛的影响
Effect of Nano-Confinement on NMR Relaxation of Heptane in Kerogen from MD Simulations and Measurements
论文作者
论文摘要
富含干酪的页岩储层将在能量过渡期间发挥关键作用，但是纳米融合对动型碳氢化合物的NMR松弛的影响知之甚少。我们使用原子化MD模拟来研究纳米填充对$^1 $ h NMR放松时间$ T_1 $和$ T_2 $ heptane在动脉基因的影响。在$ T_1 $的情况下，我们发现，从批量的heptane降低$ \ sim $ 3 $ 3的$ \ sim $ 3级数量的重要作用，与无需任何模型或免费参数的测量均与Kimmeridge页岩中溶解在Kerogen中的甲烷的测量。在$ T_2 $的情况下，我们发现禁闭会破坏空间各向同性，并引起残留的偶性耦合，从而使$ t_2 $降至$ \ sim $ 5 $ 5的数量级。我们使用模拟的$ T_2 $来校准表面松弛度，因此预测了干酪根中有机纳米por的孔径分布，而没有其他实验数据。
Kerogen-rich shale reservoirs will play a key role during the energy transition, yet the effects of nano-confinement on the NMR relaxation of hydrocarbons in kerogen are poorly understood. We use atomistic MD simulations to investigate the effects of nano-confinement on the $^1$H NMR relaxation times $T_1$ and $T_2$ of heptane in kerogen. In the case of $T_1$, we discover the important role of confinement in reducing $T_1$ by $\sim$3 orders of magnitude from bulk heptane, in agreement with measurements of heptane dissolved in kerogen from the Kimmeridge Shale, without any models or free parameters. In the case of $T_2$, we discover that confinement breaks spatial isotropy and gives rise to residual dipolar coupling which reduces $T_2$ by $\sim$5 orders of magnitude from bulk heptane. We use the simulated $T_2$ to calibrate the surface relaxivity and thence predict the pore-size distribution of the organic nano-pores in kerogen, without additional experimental data.
