Mud shale hydration and swelling are major challenges in the development of water-based drilling fluids (WBDFs). In this work, the inhibition performance and inhibition mechanism of polyethylene glycol (PEG) and potassium chloride (KCl) were investigated by hot rolling recovery tests, linear swell tests, Fourier transform infrared spectroscopy, X-ray diffraction, atomic absorption spectrophotometry and X-ray photoelectron spectroscopy. The experimental results show that the combination of PEG and KCl achieved higher recovery and lower linear swelling rate than those obtained by individual PEG or KCl. Compared to the d-spacing of Na-montmorillonite (Na-Mt) with PEG or KCl, the d-spacing of Na-Mt with PEG+KCl was lower, which indicates that KCl and PEG have synergistic inhibition effect. This synergistic effect can replace sodium ions and water molecules from the interlayer space of Na-Mt and decrease the d-spacing of Na-Mt. Based on the above experimental results and analysis, a method for optimizing PEG and KCl concentrations was proposed and further verified by rheological and hot rolling recovery tests of WBDFs. Hence, the results of this work can provide valuable theoretical guidance for developing other synergistic inhibitors.

泥页岩的水合作用和膨胀是水基钻井液（WBDF）开发中的主要挑战。在这项工作中，通过热轧恢复测试，线性溶胀测试，傅立叶变换红外光谱，X射线衍射，原子吸收分光光度法和X-射线吸收光谱研究了聚乙二醇（PEG）和氯化钾（KCl）的抑制性能和抑制机理。射线光电子能谱。实验结果表明，与单独的PEG或KCl相比，PEG和KCl的组合具有更高的回收率和更低的线性溶胀率。与使用PEG或KCl的钠蒙脱石（Na-Mt）的d间距相比，dPEG + KCl对Na-Mt的间隔降低，表明KCl和PEG具有协同抑制作用。这种协同作用可以替代Na-Mt层间空间中的钠离子和水分子，并降低Na-Mt的d间距。基于以上实验结果和分析，提出了优化PEG和KCl浓度的方法，并通过WBDFs的流变和热轧恢复测试进行了进一步验证。因此，这项工作的结果可以为开发其他协同抑制剂提供有价值的理论指导。