交替注入聚合物驱渗流场变化规律及驱油效果

SEEPAGE FIELD CHANGE RULES AND OIL DISPLACED EFFECTS OF THE ALTERNATING INJECTION POLYMER FLOODING

为了进一步提高聚合物驱效率和提高采收率,降低聚合物用量,研究了交替注入聚合物驱.应用自动化岩心驱油装置,建立平面非均质油藏物理模型,在模型上布置饱和度测量电极和测压点,研究了单一段塞注入和交替注入聚合物驱渗流场变化规律和驱油效果.结果表明：聚驱注入方式对低渗层渗流场变化影响显著,注聚过程中,单一段塞注入低渗层注入端和采出端压力差异大,主要消耗在注入井附近,交替注入压力梯度分布比较均匀;聚驱结束时,交替注入低渗层含油饱和度较单一段塞注入多降低12百分点;交替注入提高了聚合物驱效率,在降低聚合物用量25％前提下较单一段塞注入多提高采收率3.9百分点;大庆油田开展了4个交替注入聚合物驱矿场试验,节约聚合物用量26.4％,预计最终较单一段塞注入多提高采收率1.58百分点.

In order to further increase oil displaced efficiency, enhance the recovery factor and reduce the dosage, the alternating injection polymer flooding is developed. The physical model of the planar heterogeneous reservoirs is established, on which the saturation measuring electrodes and pressure measuring points are arranged with the help of automatic core-displacing device, and then the seepage field change rules and oil displaced effects of the single polymer slug and alternating injection are studied. The results show that the polymer injection patterns significantly affects the seepage field of the low-permeability. In the process of the polymer injection, the pressures of the injec- tion and production for the single slug injection change greatly in the low-permeability layers and furthermore the pressures mainly consume near the injection wells. Meanwhile, the pressure gradient of the alternating injection dis- tributes more uniform; at the end of the polymer flooding, the oil saturation of the alternating injection is 12% low- er than that of the single polymer slug in the low-permeability layer, this achievement is due to the increase of the polymer flooding efficiency. The recovery factor of the alternating injection is 3.9% more than that of the single polymer slug under the condition of 25% polymer dosage saved. Four field tests of the alternating injection polymer flooding are carried out in Daqing Oilfield, the polymer dosage is saved by 26. 4% totally and the ultimate recovery factor is expected 1.58% more than that of the single polymer injection.