Injection Order: A Determinant for the Performance of Alkaline-Surfactant and Polymer Flooding Scheme

Abstract The combined approach of alkali, surfactant, and polymer (ASP) injection is considered the most promising and enhances oil recovery by reducing residual oil saturation and improving sweep efficiency. However, the performance of ASP flooding is highly sensitive to various factors. Among these factors, the injection order of the chemical components significantly impacts the effectiveness of the process. To optimize ASP flooding, it is essential to understand the chemical interactions and mechanisms involved in each injection order. Hence, this work will evaluate the impact of injection order on the performance of ASP flooding. Computer Modelling Group (CMG) pre-processor, Builder was used for the creation of ASP input file (dataset) and STARS module for the validation of the dataset and for prediction. Six (6) order, ASP, APS, PSA, PAS, SPA, SAP were created and each evaluated for 12years, comprising of 4 years interval for each chemical components. The cumulative oil produced, oil production rate and field oil recovery factor were determined for each order. The APS order gave the highest cumulative oil production with the SPA order having the least. Similarly, APS order gave the highest field oil recover factor with the least from SPA order. The result shows that alkali must be injected first to generate soap for interfacial tension (IFT) reduction, followed by the polymer injection to change the mobility ratio and lastly, surfactant to produce an optimal surfactant concentration to further reduce the IFT between oil and formation water to an ultra-low level.