聚合物相对分子质量与油藏储层适应性研究

Experimental Study on the Reservoir Adaptability of Polymer Molecular Weight

本文针对矿场实际需求,从聚合物分子线团尺寸(Dh)测试和聚合物溶液岩心渗流特性实验入手,进行了聚合物溶液与大庆萨中开发区一二三类储层间适应性研究。结果表明,随聚合物相对分子质量增大、溶剂水矿化度减小和剪切强度降低,溶液中聚合物分子线团尺寸(Dh)增大,与之相匹配岩心孔喉尺寸增大。在聚合物溶液注入岩心过程中,若注入压力能够趋于稳定,表明该溶液中聚合物分子线团尺寸(Dh)与岩心孔喉尺寸间是匹配的。在考虑储层各小层厚度和非均质性条件下,与一类油层相适应聚合物相对分子质量应为2500×104以上,与二类油层相适应聚合物相对分子质量为1900×104~2500×104,与三类油层相适应聚合物相对分子质量为400×104~800×104。聚合物与油藏储层适应性受储层各小层厚度及其渗透率分布、聚合物相对分子质量、溶剂水矿化度和剪切强度等因素的影响,但'孔喉半径中值/分子线团尺寸Dh'范围在7~16之间。

Aimed at the actual needs,the adaptability between polymer solution and reservoir strata of Sazhong area was studied through testing molecular coil size(Dh)and core seepage characteristics of the polymer solution. The results showed that with the increase of the molecular weight of the polymer and the reduction of the salinity and shear intensity,the polymer molecule coil size(Dh)increased and the pore size matched with the polymer molecules increased accordingly. During the injection of polymer solution to the rock,the stable injection pressure indicated that polymer molecule coil size matched well with the pore size of rock.When the rock was nonhomogeneous,the molecular weight matched with the first type,the second type and the third reservoir were over 2500×104,1900×104—500×104,400×104— 800×104,respectively. The adaptability between polymer solution and reservoir strata was affected by permeability distribution,heterogeneity,molecular weight,salinity and shear intensity,and so on,the ratio of median value of throat radius to molecule coil size was between 7 and 16.