The Laboratory Experimental Research On The Strong Alkali Ternary Compound Flooding In Class Ⅱ Reservoir Of North One Area

According to the layers condition of Class II reservoir of Daqing Oilfield, we have carried out the experimental research on the displacement effect of the ternary compound flooding in artificial cores. We evaluated the strong alkali ternary compound systems including six kinds of polymers, which are the Lianhua mid-molecular weight, Lianhua high-molecular weight, 2500 molecular weight, alkali-resistance, Japan MO 4000 and France 3630. First, we had done the research on the injection pattern and measurement of viscoelasticity of the ternary compound systems with each kind of polymer, respectively, from which concluded that resistance factor and residual resistance factor increased as the increasing of the concentration of polymer, and so the viscoelasticity did. From the flooding model experiments of ternary compound flooding with different kind of polymer carried on the artificial cores of various permeability, it concluded the good ability of sweeping volume so as to select the best kind of polymer for main slug and the best optimized combination of slug. Considering factors in many aspects and the practical situation in the spot, we selected the Lianhua high--molecular weight as the best polymer, 1.2% concentration of alkali, 0.3% concentration of surfactant and 2000 ppm concentration of polymer with the amount of 0.45PV is the best main slug, the best injection pattern is that 1.2% concentration of alkali, 0.3% concentration of surfactant and 2000 ppm concentration of polymer with the amount of 0.1PV, after which is 2000 ppm concentration of polymer with 0.05PV, then alternatively 3 times.In addition, we had carried out the optimized project and the best injection pattern on the natural cores to verify the ability to enhance the sweep volume and reached the conclusion in the following. (1) The ternary compound flooding systems with best displacement effect is with Lianhua high--molecular weight polymer, which had the highest recovery. (2) The viscoelasticity and the interfacial characteristic can enhance the displacement efficiency.