高含硫钻井液缓蚀剂的合成及性能研究

SYNTHESIS OF H2S CORROSION INHIBITORS AND THEIR USE IN DRILLING MUDS

本文合成了抑制H_2S腐蚀的咪唑啉类缓蚀剂,并研究了它们的性能。正交试验表明,最佳合成条件是:反应温度:190～200℃;酸∶胺(mol比)=1∶1.05;反应时间以3～5小时为宜。根据以上条件合成的缓蚀剂,在含有3200mg/lH_2S的泥浆中,用量为0.2%时,抑制效果能达到80～90%,与碱式碳酸锌复配使用时,能提高缓蚀效率和降低碱式碳酸锌的用量,并发现缓蚀剂与CaO之间具有明显的协同效应。泥浆流变性能试验表明,缓蚀剂能提高泥浆的动切力和动塑比,对失水量影响不大。此外,利用X-射线衍射试验证明:(1)低碳钢在含H_2S的泥浆中,腐蚀产物的主要组成为Fe_9S_6;(2)H_2S会破坏FCLS的稳定性,分解出Fe^(2+),与H_2S反应生成面心立方的Fe_2S_4。

The synthesis of imidazoline derivatives as inhibitors for H_2S corrosion of the drillpipe was investigated. Experiments with weight-loss coupons in drilling muds containing 1000-3200mg/L H_2S with imidazoline inhibitors sh- owed inhibition effectiveness of 70-90% with an addition of 0.1-0.2%. If they are used together with zinc alkali carbonate, the inhibition become more effective. A synergistic effect was found between these inhibitors and CaO. These inhibitors also showed good inhibition against O_2 corrosion and good effect on the rheological properties of drilling mud. Corrosion product of mild steel in drilling muds containing H_2S was pr- oved to be kansite (Fe_9S_8) by X-ray diffraction, and it is found that H_2S is able to decompose FCLS (ferrous chromic lignosulfonate) , and reacts with Fe to form smythite (Fe_3S_4).