胺基硅醇抑制剂的制备与性能评价

Preparation and Performance Evaluation of an Amine-based Silanol Shale Inhibitor

针对高温深井钻井过程中钻井液用包被抑制剂耐温能力不足的问题,从改善高温下吸附能力角度出发,向超支化聚乙烯亚胺(HPEI)骨架分子中引入硅氧烷基团,研制出一种胺基硅醇抑制剂Si-HPEI,并对该抑制剂进行性能评价。结果表明,Si-HPEI抗黏土污染量达到35.0%以上,加量为0.5%的实验浆的滚动回收率达70.33%,抗温可达160℃,优于常规抑制剂。通过层间距测试、高温吸附性能、包被性能、疏水特性测试和微观形貌分析对Si-HPEI的作用机理进行分析。结果表明,分子链中引入硅氧烷的Si-HPEI水解后产生的硅羟基与黏土表面的硅羟基发生了缩聚反应,使Si-HPEI与黏土表面发生牢固地化学吸附,在高温下不易脱附,加强了黏土矿物片之间的作用力,有效包被黏土矿物,并改变黏土表面疏水性能,从而阻碍水分子侵入黏土层间而引起水化分散。

An amine-based silanol shale inhibitor Si-HPEI has been developed to deal with the problem of poor high-temperature stability of shale encapsulators encountered in high temperature deep well drilling.To improve the adsorptive capacity at elevated temperatures of a polymer,siloxane groups were introduced into the backbone of a hyperbranched polyethyleneimine(HPEI)molecule to produce an amine-based silanol shale inhibitor.Laboratory evaluation of Si-HPEI showed that Si-HPEI can tolerate clay contamination of up to 35.0%.Hot rolling test with a drilling fluid treated with 0.5%Si-HPEI gave a shale cuttings percent recovery of 70.33%.Si-HPEI functions at 160℃,making it a better high temperature shale inhibitor than conventional shale inhibitors.The working mechanisms of Si-HPEI were analyzed through laboratory experiments such as the measurement of the basal spacing of clays,the high temperature adsorption capacity,the encapsulation capacity,hydrophobicity and micromorphology.It was found in laboratory study that hydrolysis of Si-HPEI produces silanol groups which react through polycondensation with the silanol groups on the surfaces of clays,in this way the Si-HPEI is chemically adsorbed firmly on the surfaces of clay particles.This adsorption is so strong that it is not easy for the Si-HPEI molecules to detach from the clay particles and hence strengthens the forces between the clay particles,effectively encapsulates the clay particles and changes the hydrophobicity of the surfaces of the clays,thereby preventing water molecules from invading between clay platelets which causes hydration and dispersion of clays.