Table 3 The results of continuing HPAM and switching to BD-HMHEC flooding after water and HPAM flooding (injection rate: 0.5 mL/min).
Core No. | Polymer concentration (mg/L) | Permeability (µm2) | HPAM Injected slug (PV) | Second HPAM/ BD-HMHEC Injected slug (PV) | Incremental oil recovery (%) | ||||
|---|---|---|---|---|---|---|---|---|---|
I phase | II phase | III phase | |||||||
HPAM | BD-HMHEC | Water flooding | HPAM flooding | Switching to BD-HMHEC flooding | Continuing HPAM flooding | ||||
3-a# | 1250 | 4000 | 1.905 | 0.5 | 0.5 | 36.9 | 16.6 | — | 2.4 |
3-b# | 1250 | 4000 | 1.910 | 0.5 | 0.5 | 37.0 | 16.8 | 7.9 | — |
4-a# | 1250 | 4000 | 5.139 | 0.5 | 0.5 | 53.5 | 12.9 | — | 2.1 |
4-b# | 1250 | 4000 | 5.180 | 0.5 | 0.5 | 53.8 | 13.0 | 7.3 | — |
