新型耐特高温抗水解型聚合物驱油性能

Study on oil displacement performance of a new type of polymer with ultra-high temperature and hydrolysis resistance

胜利油区特高温油藏温度为95~120℃,目前已有的驱油用聚合物在该温度下放置30 d后水解度约为100%,黏度仅为1 mPa·s,驱油性能大幅降低,无法满足此类油藏聚合物驱要求。为了改善聚合物在特高温条件下的热稳定性和驱油性能,通过引入AMPS单体和耐特高温的N-乙烯基吡咯烷酮单体,优选了新型耐特高温抗水解型聚合物,研究了聚合物在特高温油藏下的增黏性能、流变性能、注入性能及驱油性能,重点研究了聚合物在120℃下的水解度和黏度热稳定性。结果表明,与相对分子质量相近的常规部分水解聚丙烯酰胺相比,耐特高温抗水解型聚合物初始黏度提高1倍以上,黏弹性能大幅增加,且具有良好的注入性和驱油效果,120℃下放置30 d后水解度仍为0,黏度不变,具有良好的热稳定性,有望应用在胜利油区特高温油藏,突破化学驱提高采收率温度界限。

In the Shengli Oilfield,the temperature of ultra-high temperature reservoirs is 95-120℃.The existing polymer for oil displacement,after being placed at this temperature for 30 d,has a hydrolysis degree of about 100%and viscosity of only 1 mPa·s.Its oil displacement performance is greatly affected and cannot meet the polymer flooding requirements of this type of reservoirs.To improve the thermal stability and oil displacement performance of the polymer at ultra-high tem⁃peratures,we selected a new type of polymer with ultra-high temperature and hydrolysis resistance by introducing the AMPS and NVP monomer.We studied the performance of the polymer,including viscosity-increasing,rheology,injection and oil displacement,in ultra-high temperature reservoirs,and focused on the thermal stability of hydrolysis degree and vis⁃cosity of the polymer at 120℃.The results demonstrate that compared with conventional partially hydrolyzed polyacryl⁃amide with similar relative molecular mass,the polymer in this paper has the more than doubled initial viscosity.With the viscoelastic performance greatly enhanced,it performs well in injection and oil displacement.After being placed at 120℃for 30 d,it still has a hydrolysis degree of 0 and constant viscosity,indicating great thermal stability.It is promising to be applied to the ultra-high temperature reservoirs in the Shengli Oilfield,breaking through the temperature limit of EOR by chemical flooding.