钻井液防黏附剂的合成与性能评价

Synthesis and Performance Evaluation of Anti-Sticking Agent Used in Drilling Fluid

在钻井液中加入防黏附剂,防止钻头泥包或局部被钻屑黏附是提高钻速有效手段之一。通过腐植酸磺化-酰氯化-酰胺化一系列反应合成了钻井液防黏附剂,筛选出最佳合成条件为:腐植酸与浓硫酸在质量体积比3∶5、温度160℃的条件下反应8 h,生成磺化腐植酸;然后与过量二氯亚砜在70℃下反应6 h,生成腐植酰氯;最后按腐植酰氯与脂肪胺质量比25∶4加入脂肪胺,在0～10℃下反应4 h。对防黏附剂性能的评价结果表明,防黏附剂可将钻头和岩屑表面由强亲水性转变为弱亲水性,并能大幅降低钻井液表面张力。防黏附剂质量分数由0增至1.5%时,水溶液润湿接触角由33°增至68.3°,表面张力由74.4 mN/m降为42.0 mN/m。4%膨润土浆中加入2%防黏附剂,润滑系数由0.43降至0.27;膨润土岩心在1.5%防黏附剂水溶液中的膨胀率为1.6%(2 h)和3.5%(16 h),润滑性和抑制性较好。

One of the effective means to improve the drilling speed was adding anti-sticking agent to drilling fluid which prevented bit bailing or partial of bit adhering by drilling cuttings. A drilling fluid anti-sticking agent was synthesized by a series of reaction including humic acid sulfonation, chlorination, and amidation. The optimum reaction condition was obtained as follows： humic acid reacted with concentrated sulfuric acid to generate sulfonated humic acid at 160℃ for 8 h in a ratio of mass to volume 3：5; then reacted with excess thionyl chloride to produce humic acid chloride at 70℃ for 6 h; at last the humic acid chloride reacted with fatty amine at 0-10℃ for 4 h in mass ratio 25 ： 4. The performance evaluation results showed that the anti-sticking agent could change drill bit and cuttings surface from strong hydrophilic into weakly hydrophilic, and reduce the surface tension of drilling fluid significantly. The wetting contract angle reached the maximum 68.3° from 33°and the surface tension decreased from 74.4 to 42.0 mN/m when the mass fraction of anti-sticking agent increased from 0 to 1.5%. The friction coefficient reduced from 0.43 to 0.27 when 2% anti-sticking agent was added to 4% bentonite slurry. The expansion rate of bentonite core was 1.6% and 3.5% in 1.5% anti-sticking agent solution when the test time was 2 h and 16 h respectively.