During well completion operations, the wells are killed with specific fluids to control the well. These fluids can invade and damage the formation because of fluid/rock interactions. Fluids such as fresh water, brines, and weighted fluids (e.g., barite weighted, calcite weighted, and bentonite weighted) are used to control the formations during completion operations. These fluids can invade and interact with clays and damage the formation. In addition, these fluids may alter the near-wellbore wettability and make them more oil-wet, thereby affecting the production from these formations. In this work, polyoxyethylene quaternary ammonium gemini surfactants with different types of spacers are proposed as clay swelling additives in completion fluids to mitigate the formation damage in unconventional reservoirs. Adding the new surfactants will maintain the in-situ permeability and avoid the formation damage. The novel gemini surfactants are tested on unconventional tight sandstone formation enriched with high clay content to mitigate the formation damage during well completion. The process involved a complete stabilization of clays using gemini surfactants added in deionized water (DW). Coreflooding experiments were carried out on Scioto sandstone rock samples with an average porosity of 15.6% and average absolute permeability of 0.25 md. Several coreflooding experiments were carried out with different fluids, such as potassium chloride (KCl), sodium chloride (NaCl), and different classes of gemini surfactants. Coreflooding experiments were designed in a way that the cores were preflushed with the subjected fluid and then post-flooded with DW. Results showed that the cores saturated with KCl and NaCl solutions lost permeability significantly when flooded with water while gemini surfactant solutions maintained the same permeability even after being treated with DW. Conditioning with the KCl solution resulted in a 38% reduction of permeability and that with NaCl solution resulted in an 80% reduction of permeability when treated with DW. No significant change of permeability was found for the case of gemini surfactants. This indicates that the synthesized surfactants can be used for well completion operation without any side effects.

在完井作业期间，将使用特定的流体杀死井，以控制井。由于流体/岩石相互作用，这些流体会侵入并破坏地层。诸如淡水，盐水和加重流体（例如，重晶石加重，方解石加重和膨润土加重）之类的流体用于在完井作业期间控制地层。这些流体会侵入粘土并与粘土发生相互作用，从而破坏地层。此外，这些流体可能会改变近井眼的润湿性，并使它们更加油湿，从而影响这些地层的产量。在这项工作中，提出了具有不同间隔物类型的聚氧乙烯季铵盐双分子表面活性剂作为完井液中的粘土溶胀添加剂，以减轻非常规油藏中的地层损害。添加新的表面活性剂将保持原位渗透性并避免地层破坏。新型双基表面活性剂在富含油土含量的非常规致密砂岩地层上进行了测试，以减轻完井过程中地层的损害。该过程涉及使用添加到去离子水（DW）中的双子表面活性剂完全稳定粘土。在Scioto砂岩岩石样品上进行了岩心驱替实验，平均孔隙度为15.6％，平均绝对渗透率为0.25 md。使用不同的流体（例如氯化钾（KCl），氯化钠（NaCl）和不同类型的双子表面活性剂）进行了几次岩心驱油实验。岩心驱油实验的设计方式是：将岩心先用注入的流体冲洗，然后用DW进行后驱。结果表明，浸有水的KCl和NaCl溶液饱和的岩心明显丧失了渗透性，而双子表面活性剂溶液即使经过DW处理也保持了相同的渗透性。用DW处理时，用KCl溶液进行调理会导致渗透率降低38％，而使用NaCl溶液进行调理会导致渗透率降低80％。对于双子表面活性剂，没有发现渗透率有明显变化。这表明合成的表面活性剂可用于完井操作而没有任何副作用。用DW处理时，用KCl溶液进行调理会导致渗透率降低38％，而使用NaCl溶液进行调理会导致渗透率降低80％。对于双子表面活性剂，没有发现渗透率有明显变化。这表明合成的表面活性剂可用于完井操作而没有任何副作用。用DW处理时，用KCl溶液进行调理会导致渗透率降低38％，而使用NaCl溶液进行调理会导致渗透率降低80％。对于双子表面活性剂，没有发现渗透率有明显变化。这表明合成的表面活性剂可以用于完井操作而没有任何副作用。