二类油层高质量浓度聚合物溶液性能及机理

Properties and mechanism of high mass concentration polymer solution in sub-layers

针对大庆萨北油田二类油层高质量浓度聚合物驱实际需求,利用仪器检测和理论分析方法,对高质量浓度聚合物溶液的增黏性、稳定性、抗盐性、抗剪切性、黏弹性和流动特性进行实验和机理分析.结果表明,高质量浓度聚合物溶液黏度随质量浓度增加而增大,随相对分子质量增加而增大,时间延长而降低,矿化度增加而降低,剪切强度增加而降低;聚合物质量浓度愈大,聚合物溶液黏弹性愈大;当岩心渗透率相同时,"超高分"聚合物溶液阻力因数和残余阻力因数最大,"高分"聚合物的次之,"中分"聚合物的最小;当聚合物类型相同时,岩心渗透率愈低,阻力因数和残余阻力因数愈大.与普通质量浓度聚合物溶液相比较,高质量浓度聚合物溶液具有黏弹性好和流度控制能力强等特点,可以在扩大波及体积和提高洗油效率2方面发挥作用.

The high mass concentration polymer solution flooding is a new technique for enhanced oil recovery. Currently, lots of pilot tests have been carried out in some blocks of Daqing Oilfield and have obtained a good effect in increasing oil production and controlling water. In order to satisfy actual demand for high mass concentration polymer flooding for sub-layers in Daqing Sabei Oilfield, the author implemented many experiments and theoretical analysis on its viscosity, stability, salty and shearing resistance, viscoelasticity and flow characteristics. The results show that its viscosity is affected by mass concentration, relative molecular weight, temperature, time, salinity and shearing etc. Viscosity of the high concentration polymer solution increases when mass concentration and relative molecular weight increases, then declines gradually, with its salinity and shearing increasing. The higher the mass concentration is, the higher the viscoelasticity is. When all the cores have the same permeability, the sequence of the resistance coefficient and residual resistance coefficient are as follows: 'super-high molecular' polymer solution > 'high molecular' polymer solution > 'middle molecular' polymer solution. The lower the core’s permeability is, the higher the resistance coefficient and residual resistance coefficient are, when in the same polymer solution. The high concentration polymer solution flooding has higher viscoelasticity and more powerful to control fluidity in comparison with the general polymer solution .It plays a unique role in expanding the swept volume and improving the efficiency of oil washing.