Deep drilling often faces high-temperature and high-salt environments. Bentonite/water-based drilling fluids (BT/WBDFs) suffer serious fluid loss. Polyhedral oligomeric silsesquioxane (POSS) is introduced to synthesize a hybrid fluid loss additive (PAAD) through emulsion polymerization with acrylamide and 2-acrylamido-2-methylpropane sulfonic acid, and dimethyl diallyl ammonium chloride. The hybrid polymer exhibits improved filtration control performance in BT-WBDFs under conditions with a coexisting high Na⁺ concentration and high temperature. BT-WBDFs added with 2.0% PAAD exhibit satisfactory performance for reducing fluid loss under contamination of 20% NaCl, even at a high temperature of up to 220 °C. Microstructure analysis demonstrates that forming “polymer–clay” gel through intermolecular forces and promoting clay particle dispersion efficiently stabilizes BT-WBDFs. PAAD shields against the adverse effects of Na⁺ and promotes the hydration and dispersion of BT, finally forming a thin and compact filter cake. This study can provide a basis for applying POSS in the design of efficient additives for drilling fluids.

中文翻译：

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含POSS杂化聚合物作为高温高盐抗滤失剂在水基钻井液中的应用

深井钻探经常面临高温、高盐环境。膨润土/水基钻井液（BT/WBDF）会遭受严重的滤失。引入多面体低聚倍半硅氧烷（POSS），与丙烯酰胺、2-丙烯酰氨基-2-甲基丙磺酸、二甲基二烯丙基氯化铵通过乳液聚合合成了混合降滤失剂（PAAD）。在高Na ⁺浓度和高温共存的条件下，杂化聚合物在BT-WBDF中表现出改善的过滤控制性能。添加 2.0% PAAD 的 BT-WBDF 在 20% NaCl 污染下，即使在高达 220 °C 的高温下，也能表现出令人满意的降低滤失性能。微观结构分析表明，通过分子间力形成“聚合物-粘土”凝胶并促进粘土颗粒分散可以有效稳定 BT-WBDF。 PAAD屏蔽Na ⁺的不利影响，促进BT的水化和分散，最终形成薄而致密的滤饼。该研究可为POSS应用于钻井液高效添加剂的设计提供依据。