The Research On Relative Permeability Curves Of Polymer Flooding And Alkali-surfactant-polymer Flooding System After Water Flooding

In order to get the relative permeability curves of oil phase and water phase that can accord with the fact of the oil field and supervise the production, at the same time, trying to reasonably explain the mechanism, in this paper, there are three types of natural cores, which effective permeability are about 1000, 600 and 200 md, by means of unstable state means, the relative permeability of these cores are measured, their changing trends are analyzed and contrasted.1. Separately measure the oil and water relative permeability curve of the three to the time of water cut ninety-eight.2. Separately measure the relative permeability curves of oil phase and polymer solution phase of three kinds of cores until polymer dosage gets to 0.8PV, beginning with the time of ninety, ninety-four and ninety-eight percent water cut.3.Separately measure the relative permeability curves of oil phase and alkali-surfactant-polymer system phase of three kinds of cores until alkali-surfactant-polymer system dosage gets to 0.8PV, beginning with the time of ninety-eight percent water cut.By analyzing and contrasting, we can draw conclusions as follow:1. During water flooding period, the water phase relative permeability of cores gradually increases with their permeability increasing, and the right end point of the curve removes towards right side, and the residual oil saturation declines, the skip distance between oil and water phase broadens.2. The curve shape obviously changes when polymer flooding begins at different water cut of water flooding: the oil relative permeability ascends at first, then descends. At the same time, the relative permeability of displacing phase declines at first, then ascends. The whole course trend of water cut accords with that of the displacing phase relative permeability3. For the cores of same permeability, the earlier polymer flooding is, the wider two-phase region, the lower residual oil saturation.4. For the same time of beginning polymer flooding, the higher the core permeability is, the wider two-phase region, the lower residual oil saturation, the higher the recovery.5. The injected phase relative permeability declines at first, then ascends after injecting Alkali-surfactant-polymer System, but the oil relative permeability is just opposite. Except the first one, there are another two points at which the injected phase relative permeability is equal to the oil relative permeability.6. For the same displacement process, the span between the first point and the third point at which the injected phase relative permeability is equal to the oil relative permeability is variational. the higher the natural core permeability is, the larger the span is and the lower the residual oil saturation is.