Evolution of pH and Retention of Different Alkali Species for ASP Flooding Field Applications Available to Purchase

The era of easy oil recovery is over. One of the ways to economically improve oil production is through Enhanced Oil Recovery (EOR) implementation especially in mature field development. Alkaline-Surfactant-Polymer (ASP) flooding is considered to be the most promising EOR choice between the chemical flooding options due to its great effectiveness as result of synergy between Alkaline, Surfactant and Polymer. The main objective of this work is to analyse the pH evolution of different alkali species (NaOH, Na₂CO₃ and NH₃) that should be used in ASP flooding application by using PHREEQC thermodynamic database software.

The work will divide the simulation into static and dynamic test. The static test will give result of pH evolution in terms of increasing alkali concentration in the brine to measure initial performance of each alkali species. The dynamic test will be used to simulate each alkali species performance in field application and involve of building a 1D reactive model that describe flow path of communication between injector and producer well in a reservoir and measures the pH evolution at the production well. This work will also use different reservoir brine and injection water composition for each test that will represent the onshore and offshore environment due to different amount of Total Dissolved Solids (TDS) of each case.

Through the result of this work it is found out that in onshore NaOH will be preferred based on its performance and cost, and as for the offshore environment case, NH₃ will be more preferred based on its performance and storage size. One issue to be notice for the implementation of ASP flooding in offshore that it requires the injection water to be in low salinity and that the water treatment approach is more preferred compared to pipeline construction to provide the required injection water as it is more economical.