特高矿化度Cr3+交联聚合物溶液渗流特性及其机制

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。

Seepage characteristics and mechanism of Cr3+ cross-linked polymer solution in ultra-high salinity media

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.