Shale gas as green and clean energy is attracting more interest. However, shale hydration and swelling have become the major challenges using water‐based drilling fluids, replacing oil‐based drilling fluids, for developing shale gas. In this work, a low molecular weight branched polyamine (NETS) as clay swelling inhibitor was synthesized. The NETS performed excellent inhibition property by linear expansion experiments and cuttings hot‐rolling recovery. The inhibition mechanism of NETS was investigated using X‐ray diffraction, fourier transform infrared spectroscopy, cation exchange capacity, X‐ray photoelectron spectroscopy, scanning electron microscopy, and zeta potential. The results show that the NETS can adsorb on Na‐Mt, decrease the basal spacing of wet Na‐Mt from 1.91 to 1.43 nm, and replace majority sodium ions from interlayer of Na‐Mt. However, replaceability of sodium ions and inhibition of water molecules of ethylenediamine are worse than NETS. These indicate that the primary amines of NETS had strong interaction with Na‐Mt, tensed clay layers and decrease the basal spacing. The combination of long hydrophobic chain and primary amines makes NETS to adsorb on surface of Na‐Mt, intercalate into interlayer of Na‐Mt with tilted monolayer arrangement, and replace sodium ions. The more the number of primary amine groups, the better the inhibition performance. Therefore, NETS has a great potential to be an outstanding shale inhibitor of water‐based drilling fluids in the future.

中文翻译：

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新型低分子量页岩抑制剂对蒙脱石钠溶胀的合成及机理研究

页岩气作为绿色清洁能源越来越引起人们的关注。但是，使用水基钻井液代替油基钻井液开发页岩气已成为页岩水合作用和溶胀的主要挑战。在这项工作中，合成了低分子量支化多胺（NETS）作为粘土膨胀抑制剂。通过线膨胀实验和切削热轧恢复，NETS表现出优异的抑制性能。使用X射线衍射，傅立叶变换红外光谱，阳离子交换容量，X射线光电子能谱，扫描电子显微镜和zeta电位研究了NETS的抑制机理。结果表明，NETS可以吸附在Na-Mt上，将湿Na-Mt的基础间距从1.91 nm减小到1.43 nm，并替换Na-Mt中间层中的大部分钠离子。但是，钠离子的可替代性和对乙二胺水分子的抑制作用比NETS差。这些表明NETS的伯胺与Na-Mt有很强的相互作用，拉紧了粘土层并减小了基础间距。长疏水链和伯胺的结合使NETS吸附在Na-Mt的表面上，以倾斜的单层排列插入Na-Mt的中间层，并取代钠离子。伯胺基的数目越多，抑制性能越好。因此，NETS在将来成为水基钻井液的杰出页岩抑制剂的巨大潜力。拉紧粘土层并减小基础间距。长疏水链和伯胺的结合使NETS吸附在Na-Mt的表面上，以倾斜的单层排列插入Na-Mt的中间层，并取代钠离子。伯胺基的数量越多，抑制性能越好。因此，NETS在将来成为水基钻井液的杰出页岩抑制剂的巨大潜力。拉紧粘土层并减小基础间距。长疏水链和伯胺的结合使NETS吸附在Na-Mt的表面上，以倾斜的单层排列插入Na-Mt的中间层，并取代钠离子。伯胺基的数量越多，抑制性能越好。因此，NETS在将来成为水基钻井液的杰出页岩抑制剂的巨大潜力。