腐殖酸接枝共聚物超高温钻井液降滤失剂合成

基于抗高温处理剂分子设计，采用腐殖酸与丙烯酰氧丁基磺酸(AOBS)、丙烯酰胺（AM）、丙烯酸（AA）接枝共聚，通过正交实验，在综合考虑产物的水溶液黏度、产物对钻井液黏度和降滤失效果影响的基础上，进一步考察了腐殖酸用量，最终确定了合成配方：非离子单体与离子单体比1.5:1.0、离子单体中和度100%，反应混合物质量分数50%、腐殖酸用量34%，合成了相对分子质量低的AOBS AM AA/腐殖酸接枝共聚物。对钻井液性能进行了评价，并借助红外光谱和热分析对产物进行结构表征和热稳定性分析。实验结果表明，接枝共聚物热稳定性好，抗温达到240℃，在淡水、盐水和饱和盐水钻井液中均具有较好的降滤失作用，对钻井液黏度影响较小，在膨润土含量高的钻井液中具有一定的降黏作用，可以有效地控制钻井液的高温稠化，与SMC、SMP等具有良好的配伍性，用于密度2.57g/cm³的KCl钻井液中，可以有效地控制钻井液的高温高压滤失量和流变性。

THE SYNTHESIS OF THE HUMIC ACID GRAFT COPOLYMER USED FOR ULTRA HIGH TEMPERATURE DRILLING FLUID LOSS ADDITIVE

Based on the molecular design of high temperature treatment agent，with the humic acid and acryloyloxyethylbutyl acid(AOBS),acrylamide (AM),acrylic(AA) graft copolymerization,by orthogonal experiments,in consideration of the solution viscosity of the product,the impact of the product on drilling fluid viscosity and fluid loss results,further studies of the humic acid dosage is made and the synthesis formula is determined:non ionic monomer and ionic monomer ratio is 1.5:1.0,the ionic monomers neutralization degree is 100%,the reaction mixture mass fraction is 50%,humic acid dosage is 34%.The low molecular weight AOBS AM AA / humic acid graft copolymer is synthesized,and by the using of infrared spectroscopy and thermal analysis,the structural and thermal stability of products is analyzed.Experimental results show that the graft copolymer has good thermal stability,resistant temperature reaching 240℃.It has a good fluid loss control effect both in fresh water,salt water and saturated salt water drilling fluid.Besides,it has little effect on drilling fluid viscosity.Graft copolymer has a certain viscosity reduction effect in drilling fluid which has a high content of bentonite,so it can control the high temperature thickening of drilling fluid effectively.It has good compatibility with the SMC,SMP.It can effectively control the high temperature and high pressure filtration loss volume and rheological property of drilling fluid when used in KCl drilling fluid which has a density of 2.57g/cm³.