一种改性淀粉的合成及性能评价

Synthesis and function evaluation of modified starch for drilling fluid

以玉米淀粉为原料,通过酸化、醚化、交联等改性反应合成了一种交联醚化淀粉(CM-St)。考察淀粉、氯乙酸、氢氧化钠、交联剂的含量、反应时间和反应温度对表观粘度的影响。通过正交验证,得到了合成关键工艺参数(既原料用量,时间及温度的最佳控制值)。最佳控制值下合成的交联醚化淀粉1%水溶液的表观粘度为49 m Pa·s。测定了剪切速率对CM-St糊液流变性能的影响及考察了糊液的触变性。同时,对CM-St处理钻井液的性能进行了较为详细的研究。实验结果表明,随着高粘度CM-St加量增加,钻井液的表观粘度增大,滤失量减小。

Composite modified starch（CM-St）with high viscosity by carboxymethylation and crosslinking was prepared by using corn starch,organic multi-function crosslinker and monochloroacetic as material.The pre-acid method were used in synthesis in this paper. The influencing factors on viscosity was discussed such as ratio of starch and solvent,amount of sodium hydroxide,amount of monochloroacetic acid,reaction temperature and reaction time on the crosslinking and carboxymethylation reaction.The optimum reaction formula and processing parameter were obtained by orthogonal test.The thixotropy of the CM-St paste were studied and the effects of rheological properties such as shear rate was discussed.At the same time,the drilling-fluid properties which were disposed by CM-St were studied in detail.The result show that the high viscosity CM-St can improve apparent viscosity and reduce fluid loss.