摘要
黏土防膨剂是压裂液体系中不可缺少的核心添加剂，能有效抑制黏土膨胀、防止微粒运移、增加地层渗透率。以浓盐酸、三甲胺为主原料，合成三甲胺盐酸盐，并在弱碱性条件下滴加环氧氯丙烷生成有机阳离子聚合物，最后在60℃下与无机盐氯化铵反应，得到淡黄色的黏土防膨剂。通过红外光谱、热重/差热分析、X射线衍射分析对其结构进行表征，考察了反应原料、防膨剂加量对防膨效果的影响。结果表明，随有机阳离子聚合物加量增大，防膨率提高，有机阳离子聚合物加量以0.9%为宜。有机阳离子聚合物加量相同时，随环氧氯丙烷与三甲胺盐酸盐质量比的增大，防膨率增加；当二者的质量比为2:1时，加量为0.35%、0.6%、0.9%聚合物的防膨率分别为85.87%、87.07%、89.58%，防膨效果较好。当黏土防膨剂加量为0.4%时，防膨率达90%以上；加量增至0.8%时，防膨率达94.1%，防膨效果良好。
Abstract
Clay anti-swelling agent, as an essential core additive for fracturing fluid system, possessed many excellent and distinctive characteristics, such as inhibition of clay swelling, preventing particle migrant and improving formation permeability. In this study, trimethylamine hydrochloride was synthesized by using raw material concentrated hydrochloric acid and trimethylamine, then under weakly alkaline condition, the product was modified by epichlorohydrin to get organic cationic polymer, furthermore, compound with inorganic salt ammonium chloride at 60℃ to get yellowish clay anti-swelling agent. The clay anti-swelling agent was characterized by infrared spectrum, thermal weight/differential thermal analysis and X-ray diffraction. And the influence of dosage of raw material and anti-swelling agent on the anti-swelling effect was studied. The results showed that anti-swelling ratio increased with increasing amount of organic cationic polymer. The optimum dosage of organic cationic polymer was 0.9%. When the amount of organic cationic polymer was same, the anti-swelling ratio increased with increasing mass ratio between epichlorohydrin and trimethylamine hydrochloride. When the mass ratio between them was 2:1, the anti-swelling ratio of polymer with dosage of 0.35%, 0.6% and 0.9% was 85.87%, 87.07% and 89.58%, respectively. When the working concentration was 0.4% and 0.8%, the anti-swelling ratio of clay anti-swelling agent reached 90% and 94.1%, respectively, which showed good anti-swelling effect.
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