反相乳液聚合法制备改性淀粉降滤失剂及其性能  

The Development of a Modified Starch through Inverse Phase Emulsion Copolymerization and its Performance as a Filter Loss Reducer

作　　者：朱文茜 郑秀华[1] ZHU Wenxi;ZHENG Xiuhua(School of Engineering and Technology,China University of Geosciences(Beijing),Beijing 100083)

机构地区：[1]中国地质大学(北京)工程技术学院,北京100083

出　　处：《钻井液与完井液》2021年第1期27-34,共8页Drilling Fluid & Completion Fluid

基　　金：国家自然科学基金“高温热储环境下微气泡钻井液特性及作用机理研究”(41872184)。

摘　　要：为克服水溶液自由基聚合制备改性淀粉降滤失剂存在的凝胶化问题,遵循钻井液抗高温处理剂的设计思路,采用反相乳液聚合法将淀粉与含有酰胺基/磺酸基/苯环的3种单体AM、AMPS、NVP进行接枝共聚,合成了一种新型高温抗盐抗钙降滤失剂ESt-g-NAA。首先,采用正交实验确定了反相乳液聚合的最优合成条件为:反应温度为60℃,单体物质的量比为nNVP:nAM:nAMPS=1∶2∶3,亲水亲油平衡值为5。其次,对ESt-g-NAA在3%膨润土基浆中的抗高温、抗盐和抗钙降滤失效果进行了评价,结果显示:100~180℃老化16 h后,含3%ESt-g-NAA钻井液的滤失量可控制在7.6~15.2 mL之间,且ESt-g-NAA钻井液的高温滤失量始终低于相同加量的水溶液聚合产物WSt-g-NAA。ESt-g-NAA显示了极强的抗盐和抗钙能力,在150℃老化16 h的饱和盐水钻井液中,滤失量仅为5 mL;含(0.5%~20%)CaCl_(2)的钻井液在150℃老化后滤失量控制在5.0~15.5 mL,170℃老化后可抗钙10%,但180℃老化后抗钙性能大大降低。最后,通过分析ESt-g-NAA对基浆中黏土粒度分布的影响,以及泥饼的显微观察,揭示了ESt-g-NAA的控制滤失机理。To overcome the gelling problem encountered in synthesizing modified starch filter loss reducer through aqueous free-radical polymerization,inverse emulsion polymerization was used to graph copolymerize starch with AM,AMPS and NVP whose molecules contain amide group,sulfonic acid group and benzene ring,respectively.The product of the copolymerization is a new filter loss reducer ESt-g-NAA with high temperature and salt and calcium resistance.The optimum synthetic conditions of the ESt-g-NAA were determined through orthogonal test:reaction temperature 60℃,molar ratio of the monomers nNVP∶nAM∶nAMPS=1∶2∶3,and the HLB value=5.A 3%bentonite base mud treated with 3%ESt-g-NAA had filter loss between 7.6-15.2 mL after being aged at 100-180℃for 16 h,the high temperature filter loss of the ESt-g-NAA treated mud was always less than the high temperature filter loss of the WSt-g-NAA(an aqueous polymerization product)treated mud with the concentrations of ESt-g-NAA and WSt-g-NAA in the base mud being the same.The ESt-g-NAA in the experiments showed excellent salt and calcium resistant capacities;a saturated salt water drilling fluid treated with ESt-g-NAA had filter loss of only 5 mL after being aged at 150℃for 16 h.A drilling fluid containing 0.5%-20%CaCl_(2) had filter loss between 5.0-15.5 mL after being aged at 150℃.If aged at 170℃,the drilling fluid was able to resist the contamination by 10%CaCl_(2);aging at 180℃greatly impaired the calcium resistance of the drilling fluid.The filtration control mechanisms of ESt-g-NAA were revealed by analyzing the effects of ESt-g-NAA on the size distribution of the clay particles in the base mud and by observing the mud cakes under microscope.

关 键 词：钻井液 降滤失剂 抗高温 抗盐抗钙 反相乳液聚合 淀粉接枝改性 

分 类 号：TE254.4[石油与天然气工程—油气井工程]