聚合物驱多段塞交替注入效果

EFFECTS OF MULTI-SLUG ALTERNATIVE INJECTION OF THE POLYMER FIOODING

聚合物驱区块采用单一段塞注入方式取得了较好开发效果,但出现了低渗层动用程度低、聚合物用量大等实际问题.应用水动力学采油原理创新发展了多段塞交替注入方式,即通过不同相对分子质量、不同质量浓度聚合物段塞交替注入来增加低渗层吸液量,从而有效动用低渗层剩余储量的方法.室内实验及现场试验结果表明：交替注入后油水井注采能力增加,4个试验区视吸水指数提高16.4％、采液指数提高11.3％;油层动用程度提高,小于1 m薄差油层动用厚度比例达到61.3％,在进一步提高采收率的同时降低了聚合物用量24.5％.聚合物驱交替注入方式是改善开发效果、提高聚驱效率的有效途径.

Even though the much better effects are achieved for the individual slug injection in the polymer flooded blocks, the practical problems are shown as follows ： lower developed degree of the low permeability, larger polymer volume or usage and so on. With the help of hydrodynamic oil-producing principle, the innovation of muhi-slug al- ternating injection mode is developed, namely through different molecular weight and concentration polymer slugs injected alternately to increase the low-permeability layer absorption and effectively develop the remained reserves of the low-permeability layers. The results of the indoor experiments and field tests show that after the injection, the injection-production capacities of oil and water wells are increased： the injectivity coefficients in four test blocks have reached by 16.4% ; the liquid productivity indexes have improved by 11.3% ; the developed degree of the oil reservoirs is enhanced： the developed thickness proportion of the poor and thin oil layers less than l m reaches 61.3% , the polymer volume is reduced as well as the rise of the recovery factor. Therefore, the alternating injec- tion method is the effective ways to improve the development effects and enhance the efficiency of the polymer flood- ing.