Supercritical CO₂ fracturing is a promising waterless stimulation technology, and pumping proppant during fracturing is an essential part of the frac job design to obtain a high-conductivity flow channel after the artificial fracture is created. To date, only a few laboratory experiments have been conducted using supercritical CO₂ directly to carry the proppant. In this study, an experimental system was designed to allow investigation of supercritical CO₂ transport of proppants within a fracture. To determine the supercritical CO₂ transport proppant mechanism and the impact of key operational variables, a series of laboratory experiments were performed considering various pumping schemes. The results demonstrate that the mechanism of supercritical CO₂ transport proppant includes various flow patterns such as scouring, throwing and fluidization, among which fluidization is the key to the further migration of proppant. Continued injection of clear-fluid after the addition of proppant is complete, will help the dunes extend deeper into the fracture. Fluid velocity has a significant effect on supercritical CO₂ transport proppant. While under the premise of constant mass flow rate, increasing the injection temperature, decreasing the injection pressure or reducing the proppant concentration will make the dune equilibrium height lower and the dune laying distance longer. Meanwhile, small-sized proppant particles can still be easily lifted and suspended in supercritical CO₂, and reducing proppant size significantly increases the transportability. Furthermore, dune equilibrium height correlates significantly with the variation of the Reynolds number of the fluid flow. Therefore, from a practical field operation point of view, using Reynolds number as a controlling parameter seems to be a viable option for selection of optimum pumping operational variables and prediction of proppant migration within the fracture. The results of this study are expected to provide guidance for field operators to better design operational variables (e.g. CO₂ injection rates, proppant load and pumping schedule, etc.) used for supercritical CO₂ fracturing.

超临界CO ₂压裂是一种很有前景的无水增产技术，压裂过程中泵送支撑剂是压裂工程设计的重要环节，以在人工裂缝形成后获得高导流道。迄今为止，仅使用超临界CO ₂直接携带支撑剂进行了少数实验室实验。在这项研究中，设计了一个实验系统来研究裂缝内支撑剂的超临界 CO _2传输。确定超临界 CO ₂运支撑剂机理和关键操作变量的影响，考虑各种泵送方案进行了一系列实验室实验。结果表明，超临界CO ₂运移支撑剂的机理包括冲刷、抛撒和流化等多种流型，其中流化是支撑剂进一步运移的关键。支撑剂添加完成后继续注入清液，将有助于沙丘向裂缝更深处延伸。_{流体速度对超临界CO 2}有显着影响运输支撑剂。而在恒定质量流量的前提下，提高注入温度、降低注入压力或降低支撑剂浓度，都会使沙丘平衡高度降低，沙丘铺设距离变长。_{同时，超临界CO 2}中小尺寸支撑剂颗粒仍可轻松提升悬浮，并且减小支撑剂尺寸会显着提高可运输性。此外，沙丘平衡高度与流体流动雷诺数的变化显着相关。因此，从实际现场操作的角度来看，使用雷诺数作为控制参数似乎是选择最佳泵送操作变量和预测裂缝内支撑剂运移的可行选择。这项研究的结果有望为现场操作人员更好地设计用于超临界CO ₂压裂的操作变量（例如CO _{2注入速率、支撑剂负载和泵送计划等）提供指导。}