In order to solve the problems due to the thickening of drilling fluids at low temperatures caused by the use of high-molecular-weight polymer coating agents in offshore deep-sea oil and gas drilling, a low-molecular-weight polymer coating agent named PADA was synthesized with acrylamide, methacryloxyethyltrimethyl ammonium chloride, and 2-acrylamido-2-methyl propane sulfonic acid. The PADA polymer was characterized with Fourier transform infrared spectroscopy and gel permeation chromatography. The shale inhibition effects of the PADA polymer and associated mechanisms were investigated by shale recovery and expansion experiments, transmission electron microscopy observation, particle size and zeta potential analysis, and interlayer spacing measurements. In addition, the effects of the coating agent on the filter cakes and the low temperature rheological properties of bentonite mud were also tested, and the polymer biodegradability was evaluated. The results showed that the molecular weight of the PADA polymer was 265,000 D, which was significantly lower than that of the traditional coating agents. The PADA had similar effects as two typical commercial products CAP and HPAM on inhibiting the hydration dispersion of shales and performed better than another product PAM. The inhibition effect was achieved by the polymer absorption onto the clay particles through both hydrogen bonding and the electrostatic interactions. The viscosity of bentonite mud containing PADA was much lower than that of mud with other coating agents at 4 °C, so the serious thickening caused by traditional coating agents at a low temperature could be avoided. In addition, it is relatively easily biodegraded.

为解决海上深海油气钻井中使用高分子量聚合物涂层剂导致钻井液在低温下稠化的问题，研制了一种名为PADA的低分子量聚合物涂层剂。由丙烯酰胺、甲基丙烯酰氧基乙基三甲基氯化铵和2-丙烯酰胺基-2-甲基丙磺酸合成。PADA聚合物用傅立叶变换红外光谱和凝胶渗透色谱表征。通过页岩恢复和膨胀实验、透射电子显微镜观察、粒度和zeta电位分析以及层间距测量研究了PADA聚合物的页岩抑制作用和相关机制。此外，还测试了包覆剂对滤饼的影响和膨润土泥的低温流变性能，并对聚合物的生物降解性进行了评价。结果表明，PADA聚合物的分子量为265,000 D，明显低于传统包衣剂的分子量。PADA 在抑制页岩水化分散方面具有与两种典型商品 CAP 和 HPAM 相似的效果，并且表现优于另一种产品 PAM。抑制作用是通过聚合物通过氢键和静电相互作用吸附到粘土颗粒上来实现的。含 PADA 的膨润土泥浆在 4°C 时的粘度远低于含其他包覆剂的泥浆，避免了传统包衣剂在低温下造成的严重增稠。此外，它相对容易生物降解。