Particle transport in a vertical nonplanar fracture is a typical but poorly understood element in hydraulic fracturing. Particle-fluid flow in a nonplanar fracture with a narrowing width is investigated experimentally by a laboratory-scale slot, and the relevant transport mechanisms are compared with that in the planar slot. The effects of fluid flow rate, particle density, particle size, and particle volume fraction on particle distribution are investigated. The results indicate that the narrowing width complicates the slurry flow and lowers the bed coverage area. The vortex flow appears at the contraction of the cross-section as the bed grows to a threshold height and resuspends more particles further into the slot. An irregular bed with a descending stepped surface is formed due to non-uniform placement. Smaller size sands injected at a high flow rate and a low particle volume fraction build up a smaller bed. Larger and denser particles would reverse the trend. A rational model expressed by four dimensionless numbers is developed by the linear regression method to predict the coverage percentage of the particle bed. The model and experimental results provide directions to quantitatively evaluate the particle transport and distribution in a nonplanar fracture.

垂直非平面裂缝中的颗粒传输是水力压裂中一个典型但知之甚少的要素。通过实验室规模的狭缝实验研究了宽度变窄的非平面裂缝中的颗粒流体流动，并将相关传输机制与平面狭缝中的相关传输机制进行了比较。研究了流体流速、颗粒密度、颗粒尺寸和颗粒体积分数对颗粒分布的影响。结果表明，变窄的宽度使浆料流动复杂化并降低了床层覆盖面积。当床增长到阈值高度并将更多的颗粒重新悬浮到槽中时，涡流出现在横截面的收缩处。由于放置不均匀，形成了具有下降阶梯表面的不规则床层。以高流速和低颗粒体积分数注入的较小尺寸的砂形成较小的床。更大更密的颗粒会逆转这一趋势。通过线性回归方法建立了由四个无量纲数表示的合理模型，以预测颗粒床的覆盖率。模型和实验结果为定量评估非平面裂缝中的粒子传输和分布提供了方向。