Understanding multiphase flow in fractures filled with minerals and proppants is vital in various subsurface applications. Limited experimental data have led to reliance on correlations lacking physical basis. We conducted experiments to characterize relative permeability in rough-walled fractures packed with unconsolidated porous media. We tested fractures packed with water-wet 40/70 sand (silica) and surface-coated ceramic proppants. Brine and mineral oil were used as the wetting and non-wetting fluid phases, respectively. Steady-state (SS) drainage (non-wetting-phase displacing wetting-phase) and imbibition (wetting-phase displacing non-wetting-phase) tests were performed under a wide range of saturation histories (full-cycle and scanning-curves) to study relative permeability hysteresis of the propped fractures. Every SS drainage or imbibition test consisted of several discrete points at which fluid saturations and the corresponding relative permeability were measured by varying the fractional flow rates of fluids whilst maintaining a constant total flow rate. We analyzed residual non-wetting phase saturations and relative permeability trends to understand two-phase flow behavior in each proppant pack. High-resolution x-ray microtomography was used to understand the pore-scale topology, wettability, and to provide insights about the pore-scale displacement mechanisms involved in this study. The results showed that commonly used models to estimate relative permeabilities of fractures significantly overestimated the SS brine and oil relative permeabilities (denoted as k and k) measured in this study. Further analysis unveiled that the k values during imbibition exceeded their drainage counterparts in both proppants, the ceramic proppant exhibited a lower initial water saturation and a higher end-point k permeability at the end of the drainage displacement, as well as higher k across all flooding processes. Updated fitting parameters for a Brooks-Corey-type relative permeability correlation are introduced. This study presents improved insights, extensive experimentally generated relative permeability data, and an updated relative permeability correlation, which can be collectively utilized to reduce uncertainties associated with continuum-scale forecasts of multiphase flow behavior in fractured subsurface formations.

中文翻译：

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支撑剂填充粗壁裂缝中的稳态两相相对渗透率测量


了解充满矿物和支撑剂的裂缝中的多相流对于各种地下应用至关重要。有限的实验数据导致依赖缺乏物理基础的相关性。我们进行了实验来表征填充有松散多孔介质的粗壁裂缝的相对渗透率。我们测试了用水润湿的 40/70 砂（二氧化硅）和表面涂覆的陶瓷支撑剂填充的裂缝。盐水和矿物油分别用作润湿和非润湿流体相。在各种饱和历史（全循环和扫描曲线）下进行了稳态（SS）排水（非润湿相取代润湿相）和吸入（润湿相取代非润湿相）测试研究支撑裂缝的相对渗透率滞后现象。每个SS排水或吸入测试都由几个离散点组成，在这些点上通过改变流体的分数流量同时保持恒定的总流量来测量流体饱和度和相应的相对渗透率。我们分析了残余非润湿相饱和度和相对渗透率趋势，以了解每个支撑剂填充层中的两相流动行为。高分辨率 X 射线显微断层扫描用于了解孔隙尺度拓扑、润湿性，并提供有关本研究中涉及的孔隙尺度位移机制的见解。结果表明，常用的估计裂缝相对渗透率的模型显着高估了本研究中测得的 SS 盐水和石油相对渗透率（表示为 k 和 k）。 进一流程。介绍了 Brooks-Corey 型相对渗透率相关性的更新拟合参数。这项研究提出了改进的见解、广泛的实验生成的相对渗透率数据以及更新的相对渗透率相关性，这些数据可以共同用于减少与裂缝性地下地层中多相流行为的连续尺度预测相关的不确定性。