DOI: 10.36347/sjet

Pages: 527-530

After polymer flooding, the difficulty of exploiting the potential for residual oil has increased further. Although high concentration polymer flooding can improve recovery further, the field testing shows that the injection and production is hard after the injection of high concentration polymer, so it is difficult to drive effectively, which limits the development of the high concentration polymer flooding. For the exacerbation of production decline after polymer flooding in the S pilot site PI1-2 layer of Daqing oilfield, the combination of high concentration polymer flooding and pattern infilling was presented, the laboratory experiments and numerical simulation was proceeded to study injection parameter of high concentration polymer flooding experiment in small well spacing. Research showed that injection of polymer with molecular weights of 25 millions and concentrations ranging from 2500 mg/L to 3000 mg/L were better in this block. The water cut rising to economy limit water cut of 98% after polymer flooding, and then injecting 0.5PV with concentration of 2500 mg/L polymer, the development effect was best. It could enhance oil recovery by 8.1% on basis of polymer flooding. Through optimizing the well pattern, the 106m five-spot areal well pattern was confirmed as infilled well pattern of high concentration polymer flooding.