具有缓蚀性能的页岩抑制剂在盐水钻井液性能研究

Study on the performance of shale inhibitor with corrosion inhibition in salt water drilling fluid

为了解决钻井过程中出现的井壁失稳和钻井设备出现的腐蚀问题,以4-羟基苯丙醛、超支化聚乙烯亚胺为原料制备了一种具有缓蚀性能的页岩抑制剂,应用于盐水钻井液来提高钻井效率以及保护金属。通过线性膨胀实验、膨润土造浆实验以及静态失重法评价其抑制、缓蚀性能。实验结果表明,膨润土压片在海水中的膨胀率超过100%,而在含有1%抑制剂HPEI-A的水溶液中,其膨胀率低于30%,且HPEI-A分子可通过分子间作用力以及静电作用下吸附在页岩表面,形成疏水膜,阻止水分子侵入,起到抑制黏土水化膨胀的作用,另外应用于盐水钻井液中,使N80钢的腐蚀速率低于0.015mm·a^(-1),使盐水钻井液可抗20%侵污土,表明该抑制剂与盐水钻井液具有良好的配伍性,满足现场工程要求。

In order to solve the problems of wellbore instability and corrosion of drilling equipment in the process of drilling, a shale inhibitor with corrosion inhibition performance was prepared with 4-hydroxyphenylpropanal and hyperbranched polyethylene imine as raw materials, which was applied to salt water drilling fluid to improve drilling efficiency and protect metals. Linear expansion test, bentonite inhibition text and static weight loss method were used to evaluate its inhibition and corrosion inhibition performance. Experimental results showed that the expansion rate of bentonite tablet in seawater was over 100%, but in aqueous solution containing 1% inhibitor HPEIA, the expansion rate was less than 30%. And HPEI-A molecules can be adsorbed on the shale surface through intermolecular force and electrostatic action, forming hydrophobic film, preventing water molecules from invading, and playing a role in inhibiting the hydration expansion of clay. In addition, when the inhibitor HPEI-A was applied to the salt water drilling fluid, the corrosion rate of N80 steel was lower than 0.015mm·a^(-1) and the saltwater drilling fluid can resist 20% contamination soil. It showed that the inhibitor had good compatibility with salt water drilling fluid and meet the requirements of field engineering.