控温自修复微胶囊的制备及在水合物地层固井水泥浆中的应用  

Analysis on Preparation of Temperature Controlled Self-repairing Microcapsules and Its Application in Cement Slurry for Hydrate Formation

作　　者：杨国坤 蒋国盛[1] 刘天乐[1] 覃鑫 余尹飞 YANG Guokun;JIANG Guosheng;LIU Tianle;QIN Xin;YU Yinfei(Unconventional Cementing&Special Reinforcement Laboratory,China University of Geosciences(Wuhan),Wuhan 430074,China)

机构地区：[1]中国地质大学(武汉),非常规固井与特种加固实验室,武汉430074

出　　处：《材料导报》2021年第2期2032-2038,共7页Materials Reports

基　　金：国家重点研发计划项目“乳品废水乳糖母液基微生物固井技术”(2016YFE0204300);中国地质大学(武汉)中央高校基本科研业务费专项资金。

摘　　要：当深海固井遇到天然气水合物地层时,由于水泥浆水化放热剧烈,水合物的相平衡条件发生改变,诱发水合物分解,易导致固井质量下降甚至失效。为了避免此类问题的出现,可向水泥浆中添加具有控温和水泥石开裂自修复作用的相变微胶囊,既可有效降低固井水泥浆的水化温升,又可提高水泥石的自愈性,进而增强水泥石的防渗性和力学强度。基于此,以Na 2HPO 4·12H 2O为控温芯材、硬脂酸为壁材、E-51环氧树脂为水泥石自修复材料和芯壁材粘接剂,利用油相相分离法制备了一种深水固井水泥浆控温自愈合用微胶囊。研究结果表明:当微胶囊芯壁比为1∶1.5时,芯壁间为牢固的化学-物理连接,微胶囊的包封率可达87.5%,相变潜热可达155.8 J/g,控温范围可达30~95℃。随着微胶囊含量的增加,固井水泥浆的流动性有小幅度提高,抗压强度最高可提升47.1%,抗折强度最高可提升52.2%,渗透率最多可降低61.1%。水泥浆放热峰值温度最多可降低1.8℃,峰值温度出现的时间最多可滞后520 min。Deepwater cementing in natural gas hydrate formations, due to the intense hydration of cement slurry, the phase equilibrium conditions of hydrates change, and the decomposition of hydrates is induced, which easily leads to the decline or even failure of cementing quality. To avoid such problems, the phase change reinforcing microcapsule materials can be added into the cement slurry to slow down the heat release of it du-ring the cementing process. And it can also improve the self-healing property of cement slurry while enhancing the impermeability and mechanical strength of it. In the experiment, Na 2HPO 4·12H 2O works as the temperature-control core material while stearic acid as the wall material, and the E-51 epoxy resin is used to strengthen the self-healing property of cement stone as well as to glue the core material and the wall material together. And oil phase separation is used to coat the core material. When the ratio of the core material (Na 2HPO 4·12H 2O) to the wall material (stearic acid) is 1∶1.5, the coating rate of the microcapsule is 87.5%, and the latent heat of phase change is 155.8 J/g while the temperature control range is from 30 ℃ to 95 ℃, and then there is a solid chemical-physical connection between the core material and the wall material. When different amounts of microcapsules are added into the cement slurry, it is found that the fluidity of the cement slurry improves with the increase of the amount of the microcapsule. The rupture strength can be increased by a maximum of 52.2% while the compressive strength can be increased by 47.1%, and the permeability can be reduced by 61.1% at most. As well, the temperature of the exothermic peak of the slurry can be reduced by 1.8 ℃ at most, and the retardation time can even reach 520 min.

关 键 词：深水固井 水合物地层 水泥浆水化热 控温微胶囊 水泥石自修复 

分 类 号：TB332[一般工业技术—材料科学与工程]