To meet the need of starch filtrate reducer in high-temperature drilling, a novel resin of high temperature bentonite carboxyl methyl starch (BCMS) was synthesized through chemical modification by using sodium carboxyl methyl starch (CMS-Na) and bentonite. XRD and FT-IR characterization results show that the layered structure of bentonite is broken and C-O-Si bonds are generated. The thermal stability is studied by the TG analysis, and the thermal decomposition temperature of BCMS is 290 ℃. The properties of BCMS are studied by special instruments of drilling fluid such as Portable roller oven, 6-speed viscometer and API filter press. The results show that the filter loss of BCMS is only 8. 8 mL after being heated for 16 h at 150 °C , which is 6. 2 mL less than that of CMS-Na under the same conditions, and the filter loss reduction is 41%, the apparent viscosity increases by 1 mPa ? S, and the apparent viscosity increases by 15%. The mechanism of the high temperature filtrate reduction of the BCMS was also discussed.%以羧甲基淀粉钠盐(CMS-Na)和膨润土为原料,合成了一种膨润土改性羧甲基淀粉抗高温降滤失剂(BCMS),并用XRD和FT-IR对其结构进行了表征.实验结果表明,膨润土层状结构被拆散,同时有C-O-Si键生成；BCMS的热分解温度为290℃.BCMS的钻井液性能结果显示,在150℃加热炉中高温滚动16h后,BCMS的滤失量仅为8.8 mL,比CMS-Na的滤失量降低6.2 mL；滤失量降低率41％；表观黏度较CMS-Na表观黏度增大1 mPa·s,表观黏度上升率为15％.探讨了BCMS的抗高温机理.
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