A Comprehensive Rheological Characterization of HPAM-Based Polymers for the Potential EOR Implementation

Polymer flooding is well-established and effective independent technique for improving oil recovery. However, this method is not considered viable due to the limitations such as retention at the unfavorable conditions, weak stability in the presence of divalent ions, high cost and its inability to work under high temperature-high salinity conditions. For that reason, this paper will evaluate the proper conditions and criteria for the successful implementation of polymer flooding. Four different partially hydrolyzed polyacrylamide (HPAM) based polymers were prepared using standard API procedure for polymer preparation. The effect of concentration and temperature and concentration was evaluated through different rheological measurements. The experimental studies on evaluating the performance and stability of polymers were investigated by performing long-term thermal stability and mechanical degradation tests. Thus, comprehensive rheological studies with partially hydrolyzed polyacrylamide (HPAM) based polymer solutions were designed for defining suitable polymer solution. The preliminary experimental work was carried out at 25-80 °C temperature range and at different concentrations (1000-3000ppm). All four HPAM based polymer solutions showed a typical non-Newtonian rheological characteristic with shear thinning behavior. The obtained results also showed the dependence of the polymer viscosity on the concentration and temperature. As a result, Flopaam 5115 retained and showed the maximum viscosity comparing to other polymer solutions under these conditions. Then, the performance and stability of polymers was tested through different sets of rheological experiments such as long-term thermal stability and mechanical stability tests. In this case, Flopaam 5115 also showed good thermal and mechanical resistance at 80 °C for more than one hundred days and at 23900rpm, respectively. Through the series of different rheological experiments, we identified the most suitable polymer and the conditions that would not disturb the performance and effectiveness of the particular solution. A comprehensive study on the screening different HPAM solutions showed promising results for a future investigation in this direction. The research based on different screening parameters such as concentration, temperature, time, and mechanical exposure was found to be vital for the successful implementation of polymer flooding on a field.