Laboratory of Enhanced Oil Recovery of Education Ministry, Northeast Petroleum University
The combination of profile control and flooding technology restricts the oil increasing effect. In order to solve the problems faced by the current profile control and flooding combination technology in Bohai oilfield, and promote the oil increasing effect. BZ34-2/4 reservoir was taken as the simulation object, and injection parameters and combination mode of profile control and flooding of phenolic gel/ microspheres were carried out in heterogeneous cores. The results showed that phenolic gel consist of "polymer (3000mg/L) + crosslinking agent (3000mg/L) + curing agent (3000mg/L)" had higher gelation strength and good plugging effect on high permeable layer. Supramolecular polymer microspheres with concentration of 3000mg/L had good hydration swelling effect, which could achieve macro and micro fluid diversion effect, and the two promoted each other, so as to achieve an oil increasing and water decreasing effect. With the increase of core heterogeneity, water flooding recovery decreases, and the oil recovery of profile control and flooding presents a trend of "increase first and then decrease". From the technical and economic point of view, the reasonable injection timing of profile control and displacement control is 80%~90% of water content, and the reasonable slug size of profile control agent is about 0.10PV~0.20PV, the reasonable slug size of flooding agent is about 0.20PV~0.30PV. Compared with large slug and integral injection, small slug and multiple rounds of alternate injection can reduce the retention of microspheres at the injection end and slow down the inversion speed of profile, so as to improve the effect of fluid diversion.