Multistage horizontal fracturing is the key technique in developing shale gas reservoirs. In each stage, several perforation clusters will be placed to create complex fractures, and the parameters of perforation clusters are almost the same, so the production from each perforation cluster should be similar. However, in fact, production from each perforation cluster is different vastly. If the characteristics of the shale gas reservoir where the horizontal wellbore oriented through are similar, the cause that resulted in production difference may be uneven proppant distribution among perforation clusters. In order to investigate proppant distribution through perforation clusters, the theory about proppant settling along horizontal lateral is analyzed, which can provide a proper pumping rate for future experiments. Then, an experimental model to simulate horizontal lateral and perforated clusters is designed. Fresh water was pumped to transport proppant flowing into different clusters, the volume of water and proppant through each cluster was qualified. Some parameters, such as proppant concentration, sizes, flow rate, and perforation parameters, are changed in lab tests; the simulation results will be helpful in understanding the phenomenon of uneven proppant distribution in perforation clusters. There are some conclusions from the experimental results. First, proppant settling at different positions along horizontal lateral is different when the slurry is mixed by proppant and water is pumped at different rates. Meanwhile, proppants concentration also has an influence on proppants settling. The settling of proppants will impact proppants distribution among perforation clusters. Second, at a low pumping rate, uneven proppants distribution was observed mostly. When the pumping rate was increased, the phenomenon of uneven proppants distribution was decreasing. Thus, the pumping rate is the main influential factor. Third, uneven proppants distribution can be improved or even avoided by adjusting perforation parameters, such as perforation numbers and diameter.

中文翻译：

---

页岩气藏水平井孔射孔组砂分布试验研究

多级水平压裂是页岩气藏开发的关键技术。每个阶段都会放置几个射孔簇，形成复杂的裂缝，射孔簇的参数几乎相同，因此每个射孔簇的产量应该是相似的。然而，实际上，每个射孔组的产量差异很大。如果水平井定向通过的页岩气储层特征相似，导致产量差异的原因可能是射孔簇间支撑剂分布不均。为了研究支撑剂在射孔簇中的分布，分析了支撑剂沿水平侧向沉降的理论，为后续实验提供了合适的泵速。然后，设计了一个模拟水平横向和穿孔集群的实验模型。泵送淡水以输送流入不同簇的支撑剂，通过每个簇的水和支撑剂的体积是合格的。一些参数，如支撑剂浓度、尺寸、流速和射孔参数，在实验室测试中发生了变化；模拟结果将有助于理解射孔簇中支撑剂分布不均的现象。从实验结果可以得出一些结论。首先，当泥浆与支撑剂混合并以不同的速率泵送水时，支撑剂在水平侧向不同位置的沉降是不同的。同时，支撑剂浓度对支撑剂沉降也有影响。支撑剂的沉降会影响支撑剂在射孔簇之间的分布。其次，在低抽速下，主要观察到不均匀的支撑剂分布。随着泵速的增加，支撑剂分布不均的现象逐渐减少。因此，泵速是主要的影响因素。第三，通过调整射孔参数，例如射孔数量和直径，可以改善甚至避免不均匀的支撑剂分布。