疏水改性纳米硅在聚合物驱注入井中的应用

Application of Hydrophobic Modified Nanocrystalline Silican toPolymer Flooding Injection Wells

针对油田生产中注入聚合物出现注入困难且不能连续注入的情况,研发出一种疏水改性纳米硅材料。应用时,先注入疏水改性纳米硅,对聚合物驱注入井近井地带进行改性处理,改变岩层的润湿性,然后再注入聚合物进行生产。室内实验表明,经疏水改性纳米硅处理的天然岩心注入压力降低37%左右。现场试验2口注入聚合物井,经疏水改性纳米硅处理后与常规化学解堵对比,初期注入压力降幅大,措施有效期延长75天;6口注水井经疏水改性纳米硅处理后注入聚合物,注入压力升幅和视吸水指数降幅明显减缓。相同孔隙体积情况下,与压裂后注入聚合物井对比,压力升幅减缓2. 92MPa,视吸水指数降幅减缓19. 85个百分点。经疏水改性纳米硅处理注入井连通相关采出井稳定见效,未见采聚浓度突升的突进状况。疏水改性纳米硅可有效改善聚合物驱注入井近井地带剖面,使其具有超疏水特性,保证了聚合物持续稳定的注入,实现降压增注及延长聚合物注入有效期天数的目的。

A kind of hydrophobic modified nanocrystalline silicon was developed to solve the problem of polymer being difficult to be injected or to be in-jected continuously in oilfield production.Firstly,the hydrophobic modified nanocrystalline silicon was injected to modify the near wellbore zone and to change rock wettability,and then polymer was injected for production.I ab experiment showed that the natural core injection pressure after being modified dropped by about 37%.Field tests showed satisfying results:compared with conventional plugging removed by chemicals,two polymer injection wells after being processed with hydrophobic modified nanocrystalline silicon had more inibal injection pressure decline,and the validity of measures was prolonged by 75 days;six water injection wells,after being processed with hydrophobic modified nanocrystalline silicon and polymer flooding,got lower growth rate of injection pressure and lower drop rate of apparent injectivity index.Compared W ith polymer injection wells after being fractured,the growth rate of pres-sure slowed down 2.92MPa with the same pore volume,and that the drop of apparent injectivity index decreased by 19.85%.The production wells con-nected with injection wells processed with hydrophobic modified nanocrystalline silicon were stable and efficient,and the poly mer concentration did not rise sharply.The hydrophobic modified nanocrystalline silicon could efficiently improve the profile of near wellbore zone of polymer flooding wells and make it obtain the super-hydrophobicity,which ensured steady and stable polymer injection and achieved the goal of decompression and augmented injec-tion as well as prolonging validity days of polymer injection.