EFFECT OF PORE-THROAT CHARACTERISTICS AND HETEROGENEITY ON POLYMER FLOODING IN HIGH TEMPERATURE AND HIGH SALINITY RESERVOIRS: A CASE STUDY OF DANGGANG OILFIELD IN CHINA

摘要

In order to study the effect of different pore throat characteristics and different heterogeneity on polymer displacement efficiency, pressure mercury injection technique (PMI) is used to acquire pore throat characteristic parameters of natural cores in study area, and the artificial cores are used to make the core combinations with different heterogeneity. Under the condition of high temperature and high salinity, the experiments of water and polymer flooding are carried out. The results show that the pore throat radius has the greatest influence on displacement efficiency, the larger the pore throat radius is, the higher the displacement efficiency by polymer flooding is, and the larger the coordination number is, the higher the displacement efficiency by polymer flooding is, and the bigger pore throat ratio is, the lower the displacement efficiency is. The greater the permeability differential is, the higher the enhanced displacement efficiency by polymer flooding is. The reverse rhythm core group has the highest displacement efficiency in water flooding process, the enhanced displacement efficiency of positive rhythm core group in polymer flooding process is the highest, and the final displacement efficiency is also highest. The injection velocity of polymer solution has little effect on the final oil displacement efficiency.