| At present, the main objective of tertiary recovery of polymer flooding in Daqing oil field has been transferred from class Ⅰ reservoir to class Ⅱ. Due to the heterogeneity of classⅡreservoir, currently, polymer flooding design the polymer molecular weight and concentration generally according to the mean permeability of polymer injection layer at home and abroad, which does not match the practical situation. Therefore, this thesis takes the geological features of classⅡreservoir as the research objective, the in-house physical simulation experiments are carried out by using the solution with different properties of polymers to understand its effects and rules, discuss the way of further improving effect and clarify the focus of enhanced oil recovery in water flooding and polymer flooding stage. This article designs a variety of molecular weight of polymers and injection concentration in detail for the use of physical simulation in the heterogeneous reservoir. At the same time, CT is adopted to monitor online the heterogeneous model overall and the distribution of layered remaining oil saturation. Under the condition of injection capacity allows, the final conclusion is that a larger molecular weight of polymers should be chosen as far as possible. For the second type reservoirs, the effects of middle molecule weight and the high concentration of polymer are better, which have a better injection properties after reaching a certain viscosity. In general, 16 million molecular weight of polymer and a higher concentration have a good injection effect, however the injection of a high molecular weight and a high concentration of polymer is poor. The low molecular weight and low concentration of the polymer cause viscosity to be lower and less effective. The research for this article plays an important role in the further improving polymer recovery of Daqing Oilfield, reducing the amount of polymer and increasing economic efficiency. |
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