疏水缔合聚合物与渤海储层非均质性适应性研究

Adaptation between the Hydrophobically Associating Polymer and Bohai Reservoir Heterogeneity

疏水缔合聚合物凭借良好的抗盐、抗剪切性在聚合物驱和调剖堵水中发挥重要作用的同时面临着油藏非均质性适应性问题。本文以渤海某油藏储层特征和流体性质为研究平台,在确定了疏水缔合聚合物AP-P4与目的储层孔喉配伍性的基础上,通过分析三管并联岩心(渗透率分别约4、1.5、0.5μm2)实验中的聚合物浓度变化对小层分流率和驱油效果的影响,开展了疏水缔合聚合物与储层非均质性的适应性研究。结果表明,随AP-P4浓度的增加,聚合物溶液的黏度和分子线团尺寸增大,相近渗透率下的阻力系数和残余阻力系数增大。AP-P4浓度为1500、1750和2000 mg/L时,与其相对应的岩心渗透率极限分别为1150×10-3、1500×10-3和1780×10-3μm2。聚合物浓度变化不仅会影响剖面反转时机,还会影响聚合物溶液在各小层中的驱替能力。聚合物浓度在1500~2000 mg/L范围内,随着聚合物浓度增加,聚合物与储层非均质性适应性变差,中、低渗透层受效波及区域减小,剖面反转时机提前,采收率呈现出先增加后减小的趋势,在聚合物浓度为1750 mg/L时实验增油效果最好,表明疏水缔合聚合物与储层非均质性的适应性对原油采出程度至关重要。

Hydrophobic associating polymer plays an important role in polymer flooding,profile control and water plugging for its fine salt resistance and shear resistance,however,there is the problem of adaptation with reservoir heterogeneity at the same time.In the paper,using reservoir characteristics and fluid properties of Bohai as studying platform,the compatibility between hydrophobic associating polymer AP-P4 and reservoir pore throat was confirmed,and then the adaptation between AP-P4 and reservoir heterogeneity was studied through analyzing the influence of polymer concentration changes on flow rate of small layers and displacement efficiency in parallel linear cores(the permeability was 4,1.5,0.5 μm2,respectively). The results showed that as the concentration of AP-P4 increased,the viscosity and molecular coil dimension of AP-P4 solution increased,the resistance factor and residual resistance factor also increased under similar permeability. When concentrations of AP-P4 was 1500 mg/L,1750 mg/L and 2000 mg/L,respectively,the corresponding permeability limits was 1150 × 10-3μm2、1500 × 10-3μm2and 1780 × 10-3μm2,respectively. The change of polymer concentration affected not only the time of profile inversion but also the displacement ability of polymer in all small layers. When polymer concentration ranged in 1500—2000 mg/L,with the concentration increasing,the adaptation between hydrophobic associating polymer and reservoir heterogeneity got worse,the affected area of medium and low permeability layer got smaller and profile inversion time moved up,and the oil recovery firstly increased then decreased.Displacement efficiency reached the best at the concentration of 1750 mg/L,indicating that the adaptation between hydrophobic associating polymer and reservoir heterogeneity is very important to oil recovery.