Research On Performance Evaluation And High Temperature Polymer Injection Method

This paper is about the BHY polymer injection experiment and displacement performance research for the high temperature(95℃) of Shuanghe reservoir. Analysis the microscopic differences of two cores by the distribution of T2 spectrum of NMR. Explore the causes in the recovery of polymer flooding.BHY polymer injection experiment results show that BHY polymer has a good injection performance. The loss factor of polymer solution viscosity changed little with the increase of injection rate; the artificial core is 6.33% and natural core is 7.21%. The concentration of polymer solution has great influences on the resistance coefficient and less influences on the residual resistance coefficient.Under the condition of similar permeability, the resistance coefficient of natural core is only half of the artificial core and close to the average residual resistance coefficient, it shows that the natural core has macroscopic throats.The displacement performance of heat-resistant polymer is evaluated with the artificial cores and natural cores under 95℃. The best concentration of BH heat-resistant polymer is 1500 mg/L, and the best slug is 0.6 PV on the condition of the average permeability is 600×10-3μm2 of the homogeneous core and the oil viscosity is 2.3mPa ? s. Under the best concentration and the PV size, BH heat-resistant polymer solution has better displacement effect for the artificial double core whose permeability ratio is less than 4. When permeability ratio exceed 4, the displacement affect no longer increase. When the mobility ratio increase from 0.05 to 0.2, for the artificial cores, the recovery of polymer flooding reduce by 3.17%, and for the natural cores, the recovery of polymer flooding reduce by 2.26%. The recovery of BH polymer that is aged for 90 days after vacuumed is 32.29%. Comparing with the fresh BH polymer, it is lower by 6.56%. That is to say that the aged BH polymer still has good oil displacement efficiency.The T2 distribution of NMR shows that in the natural core, the pore radius of natural core is 0.27μm and its frequency is 0.31, the pore radius is 4.88μm and its frequency is 0.62, the pore radius is 17.12μm and its frequency is 0.07. We can find that the heterogeneity of the natural core is serious and the pore radius distribution is scattered. For artificial core, the pore radius is 0.1μm and its frequency is 0.07. The pore radius is 3.96μm and its frequency is 0.93. It shows that the artificial core has good homogeneity.