水基恒流变钻井液流型调节剂的制备与性能评价

Evaluation on Preparation and Performance of Rheological Modifier Used in Flat-rheology Water-based Drilling Fluid

黄 孟 许 林 许 洁 高 涵 由福昌 刘卫红

HUANG Meng XU Lin XU Jie GAO Han YOU Fuchang LIU Weihong

流型调节剂是实现水基钻井液恒流变特性的关键处理剂。以丙烯酸（AA）、丙烯酰胺（AM）、2-丙烯酰胺基-2-甲基丙磺酸（AMPS）单体为主要原料，采用反相微乳液方法合成了一种流型调节剂，表征了产物的结构、分子形貌、热稳定性等，比较了流型调节剂与传统处理剂对水基钻井液流变性能的影响，结合流型调节剂的分子聚集态结构分析了恒流变机理。结果表明，流型调节剂黏均分子量约 7.5×106，平均粒径为 258.7 nm，抗温可达260℃。在水基钻井液中，流型调节剂具有良好的流变控制能力，可显著降低温度变化（4～ 65℃）对关键流变参数的影响。流型调节剂分子的核-壳结构提高了分子刚性和稳定性，其亲水基团在壳层的层级分布可补偿基团损耗，从而维持有效基团数量，确保与黏土片层的缔合作用，维持水基钻井液的稳定性。图 6表 1参21

Rheological modifier was a key additive to enable flat rheology property for water-based drilling fluids. A specific rheological modifier was synthesized by reverse microemulsion method using acrylic acid （AA），acrylamide （AM） and 2-acrylamido-2-methyl-propane sulfonic acid （AMPS） as raw materials. The structure，morphology and thermal stability of synthesized product were characterized. Meanwhile，the rheological behavior of rheological modifier and traditional viscosifier in water-based drilling fluid was comparatively investigated. Also，the flat-rheology mechanism of water-based drilling fluid was explored，in combination with the molecular aggregation structure of rheological modifier. The results showed that the average molecular weight of rheological modifier was 7.5×106，the average particle size was 258.7 nm，and the temperature resistance was high up to 260℃ . In water-based drilling fluid，the rheological modifier adjusted the rheological property well，which could dramatically reduce the influence of temperature variation （4—65℃） on rheological parameters. It was concluded that the core-shell structure of rheological modifier should reinforce molecular rigidity and stability. In particular，a layer distribution of hydrophilic radicals around the shell could compensate radical loss caused by harsh environment，and sustain the total quantity of effective radicals. As a result，the association action between polymeric molecular and clay layers could be well maintained，and the flat-rheology of water-based drilling fluid could be realized.