聚合物驱多段塞交替注入方式及现场应用

Multi-slug alternative injection method and field application of polymer flooding

针对目前低渗透层动用程度低、部分聚合物驱区块注入困难、聚合物用量过大等实际问题，探索通过多段塞交替注入方式进一步改善聚合物驱效果，提高聚合物驱效益。应用物理模拟实验方法，对非均质油层依次交替注入不同粘度的聚合物段塞，使高、低渗透层驱替剂流度差异减小，实现高、低渗透层聚合物段塞尽可能同步运移。实验结果表明，合理的多个段塞交替注入驱油方案较单一段塞注入多提高采收率2％以上，节省聚合物用量约25％。将该注入方式应用于大庆油区4个试验区，结果表明，有效控制了含水率上升速度，综合含水率较预测值低0．8％，增加产油量1．4×10^4t，节省聚合物干粉用量18．6％。多段塞交替注入方式是提高聚合物驱效率、降低聚合物用量的有效措施。

At present,the producing degree of low permeability layers is low,some polymer flooding blocks are injected abundant- ly and the amount of polymer dry chemical is high.In view of these questions,the effect of polymer flooding can be further improved through the method of multi-slug alternative injection,which can improve the benefit of the polymer flooding.Applying the physical simulation experiment methods,polymer slug with different viscosity can be alternatively injected in turn for anisotropic layer,which can reduce the mobility contrast of displacing agent of high permeability layers and low permeability layers and polymer slug of them can synchronously move.The experiment results show that the oil displacement program of reasonable multi-slug alternative injection can improve the oil recovery more than 2%compared to single slug injection and the amount of polymer dry chemical can be saved by about 25%.After field application,it can control the rising rate of water cut,the composite water cut is dropped by 0.8%,increasing oil production of 1.4x10 t and saving polymer dry chemical by 18.6%,thus it can prove that the multi-slug alternative injection is an effective action to improve the polymer flooding efficiency and decrease the amount of polymer.