特高矿化度Cr^(3+)交联聚合物溶液渗流特性及其机制

Seepage characteristics and mechanism of Cr^(3+) cross-linked polymer solution in ultra-high salinity media

针对特高矿化度油藏深部调剖需求,研制具有优良抗盐性的Cr3+交联聚合物溶液,用黏度计、动态光散射仪、流变仪和岩心流动等实验方法对其进行表征,研究矿化度对Cr3+交联聚合物溶液黏度、分子线团尺寸、黏弹性和流动特性的影响。结果表明:与聚合物溶液相比,Cr3+交联聚合物溶液的黏度略有下降,分子线团的尺寸小幅增加,黏弹性有所上升,阻力系数和残余阻力系数大幅度增加;当预热时间较短时,随着溶剂水矿化度的增加Cr3+交联聚合物溶液的阻力系数和残余阻力系数逐渐增大;当预热时间较长时,随着矿化度的增加阻力系数和残余阻力系数逐渐减小;在Cr3+交联聚合物溶液中,交联反应首先发生在同一分子的不同支链间(简称分子内交联),然后扩展到不同聚合物的分子链间(简称分子间交联),形成区域性网状聚集态。

A new type of Cr3＋ cross-linked polymer solution with good salt resistance was developed due to the demand of deep fluid diversion technique in the ultra-high salinity reservoir.Bush viscometer,dynamic light scattering,rheometer and core flow experimental device were used to characterize this solution.The influences of mineralization on the viscosity of the Cr3＋ polymer solution,molecular coil dimensions,viscoelasticity and flow characteristics were investigated.The results show that compared with the polymer solution,the viscosity of Cr3＋ polymer solution decreases slightly,the molecular coil dimensions of Cr3＋ polymer solution increase slightly,the viscoelasticity of Cr3＋ polymer solution increases,and the drag coefficient and residual resistance coefficient of Cr3＋ polymer solution significantly increases.When the preheating time is shorter,the drag coefficient and residual resistance coefficient of Cr3＋ polymer solution gradually increase with the increase of salinity.However,when the preheating time becomes long,the drag coefficient and residual resistance coefficient of Cr3＋ polymer solution gradually decrease with the increase of salinity.In the Cr3＋ cross-linked polymer solution,the cross-linked reaction preferably occurrs between the different branched-chain of the same molecule,i.e.intra-molecular cross-linked,then the cross-linked reaction extends to the different polymer molecular,i.e.inter-molecular cross-linked,and form regional dictyoaggregate state.