Archive | 2019
Polymer Throughput Effects on Injectivity and Retention
Abstract
Summary In this work, we investigate the effects of throughput (volume of polymer solution injected) on injectivity and retention. High throughput is representative of the near-wellbore area. It is important to investigate throughput effects to safeguard against excessive polymer retention and/or injectivity losses. Single-phase displacement experiments were performed at reservoir conditions using polyacrylamide polymers and representative reservoir brines and core samples. Tests were conducted at high flowrates to mimic the near-wellbore conditions. One test with extended polymer injection was performed to investigate throughput effects. The effluent polymer concentrations were analyzed by total organic carbon (TOC) measurements for determining polymer retentions. Pressure measurments were used to infer residual resistance factors (hence injectivity losses). Results showed that the polymer dynamic retention results were generally very close, ranging from 0.128 to 0.204 mg/g-rock. Higher throughput yielded only a slight increase in retention. Furthermore, residual resistance factor (RRF) was relatively low, ranging from 1.20 to 1.39. There was no appreciable increase in RRF even after injection of around 100 PV of polymer solution. These results indicate that injection of large pore volumes within the near wellbore region do not have significant impact on water injectivities at least for the studied system.