摘要
Abstract
With the increase of oilfield development and watered-out degree, polymer flooding technique is used to improve oil displacement efficiency. However, since the physical property difference between polymer and water often causes the variation of electric property for watered-out zone in polymer-flooding oilfield, its conductive theory should be studied further. Based on the experimental measurements of polymer-flooding rock samples with different formation water salinities, we find out the ratio of polymer solution resistivity to formation water resistivity large-ly affects the variation of the resistivity of watered-out zone, and the relationship of formation re-sistivity and water saturation ordinarily shows monotonic decrease type, "L" type, and dissym-metrical "U" type as the ratio increases. Considering the change of resistivity of mixing solution with water cut and the ion exchange between polymer solution and formation water, we propose a new model to calculate the resistivity of mixing solution. Herein, an effective medium resistivity model for the watered-out zone has been derived on the basis of symmetrical anisotropic effective medium conductance theory, experimental measurements of polymer-flooding rock samples, and distribution of oil and water in pores of the watered-out zone under high water cut stage. Theo-retical simulation and experiments indicate that the proposed model can describe the resistivity change for watered-out shaly sand reservoirs in polymer-flooding oilfield. Comparison of calculat-ed water saturation with measured water saturation shows that the proposed model can improve the accuracy of evaluation on water-flooded zone in polymer-flooding oilfield.关键词
测井解释/聚合物驱/混合液电阻率/水淹层/对称各向异性导电理论/电阻率模型Key words
Log interpretation, polymer-flooding, resistivty of mixing fluid, water-floodedzones, symmetrical anisotropic conductance theory, resisivity model分类
天文与地球科学
