Abstract In this study, lab research was performed to obtain a method to determine the timing for early polymer injection in oilfields, to increase applicability of lab research in actual oilfield management and to identify the optimum timing for polymer flooding to ensure efficient development of offshore oilfields. This study optimized the methods for lab experiments on oil displacement, analyzed the characteristics of two-phase flow permeability experiments, identified the effect of early polymer flooding, and found the method to decide the timing for early polymer flooding applicable to real-world oilfield management. The research result shows that there is optimum timing for early polymer flooding: in the case that a reservoir’s oil viscosity is 70mPa ⋅ s, the optimum timing is when the water cut is within the range from 0% to 40%. The water cut increase rate and the water/oil mobility ratio are key factors to the performance of polymers in mobility control: the best control effect can be achieved when the water/oil mobility ratio is below 1 and before the water cut increase rate reaches the maximum. Before polymer flooding, injection of a certain volume of water can unclog the channels, give full play to the effect of waterflooding, reduce the pressure of polymer injection, and cut the loss of effective viscosity of the polymer solution. In actual oilfield development, it is feasible to predict and monitor changes in the oil productivity index and take the timing of sharp decrease of the index as the optimum timing for polymer flooding.

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砂岩储层早期注聚最佳时机研究

摘要 本研究旨在获得一种确定油田早期注聚时机的方法，提高实验室研究在实际油田管理中的适用性，确定聚合物驱的最佳时机，以确保海上油田的高效开发。 . 本研究优化了室内驱油实验方法，分析了两相流渗透率实验的特点，识别了早期聚合物驱的影响，找到了适用于实际油田管理的早期聚合物驱时间的确定方法。 . 研究结果表明，早期聚合物驱存在最佳时机：在油藏原油粘度为70mPa·s的情况下，最佳时机是含水率在0%～40%之间。含水率增加率和水油流度比是影响聚合物流度控制性能的关键因素：水油流度比小于 1 和含水率增加率达到最大。在注聚前，注入一定体积的水可以疏通通道，充分发挥注水效果，降低注聚压力，减少聚合物溶液有效黏度的损失。在实际油田开发中，可以预测和监测产油指数的变化，将指数急剧下降的时机作为聚合物驱的最佳时机。当水油流度比小于1，含水增加率达到最大值之前，控制效果最好。在注聚前，注入一定体积的水可以疏通通道，充分发挥注水效果，降低注聚压力，减少聚合物溶液有效黏度的损失。在实际油田开发中，可以预测和监测产油指数的变化，将指数急剧下降的时机作为聚合物驱的最佳时机。当水油流度比小于1，含水增加率达到最大值之前，控制效果最好。在注聚前，注入一定体积的水可以疏通通道，充分发挥注水效果，降低注聚压力，减少聚合物溶液有效黏度的损失。在实际油田开发中，预测和监测采油指标的变化，将指标急剧下降的时机作为聚合物驱的最佳时机是可行的。降低聚合物注射压力，减少聚合物溶液有效粘度的损失。在实际油田开发中，可以预测和监测产油指数的变化，将指数急剧下降的时机作为聚合物驱的最佳时机。降低聚合物注射压力，减少聚合物溶液有效粘度的损失。在实际油田开发中，可以预测和监测产油指数的变化，将指数急剧下降的时机作为聚合物驱的最佳时机。