Abstract A high molecular weight copolymer consisting of 2-acrylamido-2-tert butyl sulfonic acid (ATBS) and N,N-dimethyl acrylamide (NNDMA) was encapsulated in a natural rubber latex matrix and evaluated relative to its functionality as thermally activated, delayed release anti-settling agent in well cementing. Successful incorporation of CaATBS-co-NNDMA was confirmed via scanning electron microscopy and energy dispersive X-ray spectroscopy. It was found that the composite material has only minor influence on the viscosity during slurry mixing at the surface, whereas starting at 80 °C the viscosifying polymer is gradually released and thermal thinning of cement slurry is suppressed. Thereby preventing the sedimentation of cement particles which can result in a failed cement job. The effectiveness of the composite material is owed to the release of CaATBS-co-NNDMA when the rubber matrix softens at elevated temperatures. High-temperature/high-pressure (HT/HP) consistometer testing including off/on-cycles demonstrated that the polymer successfully prevents the settling of cement at temperatures up to 180 °C. The encapsulated product presented here delivers a solution to mitigate high surface rheology of the cement slurry during mixing and counteract the effect of thermal thinning at elevated temperatures, thus making cementing operations more successful and safer under such conditions. The method introduced in this paper might be suitable to encapsulate any other additive which is to be released at increased temperatures.

中文翻译：

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井用水泥浆高温防沉剂的制备及效果

摘要 将一种由 2-丙烯酰胺-2-叔丁基磺酸 (ATBS) 和 N,N-二甲基丙烯酰胺 (NNDMA) 组成的高分子量共聚物封装在天然橡胶胶乳基质中，并评估其热活化、延迟固井时释放防沉剂。通过扫描电子显微镜和能量色散 X 射线光谱证实了 CaATBS-co-NNDMA 的成功掺入。结果表明，复合材料对表面泥浆混合过程中的粘度影响很小，而从 80°C 开始，增粘聚合物逐渐释放，水泥浆的热稀化得到抑制。从而防止可能导致水泥作业失败的水泥颗粒沉降。复合材料的有效性归因于当橡胶基质在升高的温度下软化时释放 CaATBS-co-NNDMA。包括关闭/开启循环在内的高温/高压 (HT/HP) 稠度计测试表明，该聚合物成功地防止了水泥在高达 180 °C 的温度下沉降。此处介绍的封装产品提供了一种解决方案，可减轻混合过程中水泥浆的高表面流变性，并抵消高温下的热稀释效应，从而使固井作业在这种条件下更加成功和安全。本文中介绍的方法可能适用于封装任何其他将在升高的温度下释放的添加剂。包括关闭/开启循环在内的高温/高压 (HT/HP) 稠度计测试表明，该聚合物成功地防止了水泥在高达 180 °C 的温度下沉降。此处介绍的封装产品提供了一种解决方案，可减轻混合过程中水泥浆的高表面流变性，并抵消高温下的热稀释效应，从而使固井作业在这种条件下更加成功和安全。本文中介绍的方法可能适用于封装任何其他将在升高的温度下释放的添加剂。包括关闭/开启循环在内的高温/高压 (HT/HP) 稠度计测试表明，该聚合物成功地防止了水泥在高达 180 °C 的温度下沉降。此处介绍的封装产品提供了一种解决方案，可减轻混合过程中水泥浆的高表面流变性，并抵消高温下的热稀释效应，从而使固井作业在这种条件下更加成功和安全。本文中介绍的方法可能适用于封装任何其他将在升高的温度下释放的添加剂。此处介绍的封装产品提供了一种解决方案，可减轻混合过程中水泥浆的高表面流变性，并抵消高温下的热稀释效应，从而使固井作业在这种条件下更加成功和安全。本文中介绍的方法可能适用于封装任何其他将在升高的温度下释放的添加剂。此处介绍的封装产品提供了一种解决方案，可减轻混合过程中水泥浆的高表面流变性，并抵消高温下的热稀释效应，从而使固井作业在这种条件下更加成功和安全。本文中介绍的方法可能适用于封装任何其他将在升高的温度下释放的添加剂。