Hydration of shale formation by water‐based drilling fluids leads to several problems, such as the collapse of boreholes, tight holes, and stuck pipe, which may impede further drilling and time loss in rectifying the problems, leading to heavy economic losses. This study reports the development of new gemini cationic surfactants as shale‐swelling inhibitors. These gemini surfactants are structurally similar but differ in terms of the spacer group. Saturated butyl group (GS1) and unsaturated 2‐butenyl (GS2) and 2‐butynyl (GS3) were introduced as spacer groups of gemini surfactants. To assess the performance of new gemini cationic surfactants, two reliable clay sources were considered. The first clay is from an unconventional formation and the second clay is sodium bentonite. The inhibition characteristics of gemini surfactants were evaluated using dynamic swelling, hot rolling, rheology, and filtration experiments. Different formulations based on commercially available solutions for shale‐swelling inhibitors were applied and compared with cationic shale inhibitors. It was observed that the new gemini cationic surfactants with different spacers (saturated and unsaturated) reduced the shale swelling by different percentages. The GS2 surfactant, containing an unsaturated double bond proved to be a good swelling inhibitor as compared to GS1 and GS3. It also showed acceptable performance compared with the common shale inhibitor (KCl) used in the industry. The addition of surfactant has less impact on the rheological properties as compared to KCl. The filtration properties of the base mud were unchanged when surfactants were used. However, the commercial inhibitor, KCl, significantly increased the filtration volume that is associated with the disintegration of the clay. In summary, unlike commercial inhibitors, the synthesized surfactants reduced the clay swelling without affecting the other properties of the drilling fluids.

中文翻译：

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使用具有不同间隔基的新型阳离子双子表面活性剂抑制粘土膨胀

水性钻井液使页岩形成水化会导致一些问题，例如井眼塌陷，小孔和管道卡死，这可能会阻碍进一步的钻井和纠正问题的时间损失，从而造成巨大的经济损失。这项研究报告了作为页岩溶胀抑制剂的新型双子阳离子表面活性剂的开发。这些双子表面活性剂在结构上相似，但是在间隔基团方面不同。饱和丁基（GS1）和不饱和2-丁烯基（GS2）和2-丁炔基（GS3引入）作为双子表面活性剂的间隔基。为了评估新型双子阳离子表面活性剂的性能，考虑了两种可靠的粘土来源。第一种粘土来自非常规地层，第二种粘土为钠膨润土。使用动态溶胀，热轧，流变学和过滤实验评估了双子表面活性剂的抑制特性。应用了基于市场上可买到的页岩膨胀抑制剂溶液的不同配方，并将其与阳离子页岩抑制剂进行了比较。观察到，具有不同间隔基（饱和和不饱和）的新型双子阳离子表面活性剂可降低页岩溶胀的百分数。该GS2与GS1和GS3相比，含有不饱和双键的表面活性剂被证明是良好的溶胀抑制剂。与工业上常用的页岩抑制剂（KCl）相比，它也显示出可接受的性能。与氯化钾相比，添加表面活性剂对流变性能的影响较小。当使用表面活性剂时，基础泥浆的过滤性能没有变化。但是，商业抑制剂氯化钾显着增加了与粘土崩解有关的过滤体积。总之，与商业抑制剂不同，合成的表面活性剂在不影响钻井液其他性能的情况下减少了粘土膨胀。