低渗透油层聚合物驱注入参数的确定

Determination of polymer flooding parameters for low permeable reservoirs

大庆喇萨杏油田经过近50 a的注水开发已进入特高含水期。在后续聚合物驱开发中,高渗透厚油层的聚合物驱基本结束,中低渗透油层聚合物驱技术已进入工业化推广阶段。室内实验研究了不同分子质量聚合物对低渗透油层的适应性,同时根据室内物理模拟实验和数值模拟,研究确定了大庆油田中部高台子油层的注入参数。相对分子质量在600×10~4～1000×10~4的聚合物适合渗透率0.050～0.100μm^2的低渗透油层;确定聚合物最佳注入参数为:注入聚合物分子质量为1 000×10~4,浓度为800 mg/L,注入速度为0.10 PV/a,聚合物用量560 mg·L^(-1)·PV^(-1)。该研究为指导低渗透油层聚合物驱技术的矿场应用提供了新的理论依据。

The La-Sa-Xing reservoir in Daqing Oilfield has been in the stage of extra high water cut after almost 50 years of water flooding.High permeability thick reservoirs have almost been developed and medium-low permeability reservoirs become new targets of polymer flooding.The adaptability of polymers with different molecular weight to low permeability reservoirs in Daqing Oilfield has been studied through laboratory experiments,and the injection parameters for Caotaizi reservoir in the middle of Daqing Oilfield are determined according to physical modeling and numerical simulation.The result shows that a polymer with relative molecular weight between 600×10~4～1 000×10~4 is fit for reservoirs with permeability between 0.050～0.100μm^2.The optimum polymer injection parameters are molecular weight 1 000×10~4,concentration 800 mg/L,injection rate 0.10 PV/a,volume 560mg/ L^(-1)?PV^(-1).This study provides theoretical basis for field application of polymer flooding in low permeability reservoirs.