Research on Optimal Blocking Limits and Injection Parameter Optimization of Polymer Microsphere Conformance Control

Polymer microsphere (PM) profile control has been attributed to improving sweep efficiency during the oil development process. The critical factors for PM conformance control are the plugging properties controlled by matching the relationship between the throat diameter and particle size and the injection parameters. A new matching relationship between the reservoir and PM based on the function of blocking rate and the ratio of throat diameter to microsphere diameter (CR) is established to choose the most appropriate PM size. The blocking rate indicates that it will get the most excellent plugging effect when CR is 0.5. The displacement experiments under different injection concentrations and other injection volumes show that the blocking rate is increased by injection concentration and finally stabilized. A similar trend is presented between the injection volume and plugging rate. The optimal injection concentration is 0.5%, and the optimal injection volume is 0.3 PV. According to the new size selection method and injection parameter optimal method, PM100 chooses to conduct field application. PM100 presents a good performance with a success rate of 37.5% and a validity period of more than 120 days, and its daily oil production rate increased 1.7 times, on average, and finally, the total oil increase is 556 t. The optimal size microsphere shows a good EOR effect, which indicates that this size selection method is reasonable.