Optimizing Surfactant Polymer Flooding: Integrated Study from Molecular Dynamics Simulation to Chemical Cost per Incremental Oil

Abstract

The effectiveness of surfactant formulation to extract the trapped oil in the mature oil field has been studied for many years, especially in Indonesia where the majority of oil fields are on declining stage. The main objective of this research was to demonstrate how to develop excellent surfactant formulation along with polymer to maximize the production of oil. Surfactant formulation that in charge for lowering the interfacial tension (IFT) of oil and water, decrease the capillary forces and generating mobile oil consists of local biosurfactant derived from palm oil and commercially available co-surfactant to obtain synergistic mechanism of oil and water, whereas polymer is added to reduce the mobility ratio between displacing fluid and displaced fluid for improving sweep efficiency The study starting with molecular dynamics simulation to screen the potential biosurfactant and synthesizing the selected one. Synthesized biosurfactant was tested including IFT measurements, and phase behavior investigation at several formulations with various ratio and concentration of biosurfactant and co-surfactant to obtain the best surfactant formulation. Polymer was then added to evaluate the surfactant performances in representative standard core. The cost effective of surfactant polymer formulation to increase the oil production was also calculated. It was found that surfactant formulation which exhibiting the lowest IFT and the highest microemulsion consist of biosurfactant and co-surfactant with the ratio 1:1 (OFTD11) at a given salinity. A series of flooding experiment utilizing varies surfactant polymer formulation which performed on sandstone standard core showed that OFTD11 was able to obtain maximum oil recovery with injection of 0.3 PV surfactant polymer followed by 0.6 PV polymer resulting in recovery factor as high as 45.19 %IOIP (initial oil in place). It showed that the volume of microemulsion formation is directly proportional to the recovery factor of chemical flood, indicate the importance of microemulsion for optimum oil recovery. This high performance of chemical injection described from chemical injection cost as low as 1.42 USD/bbl chemicals injected or 4.52 USD/barrel incremental oil with the price of biosurfactant 4.17 USD/kg, co-surfactant 4.25 USD/kg and polymer 3.3 USD/kg. Systematic methods begin with molecular dynamics simulation to the economical chemical cost are required on developing the suitable chemical formulation that is specific for certain
reservoir in order to achieve the cost effective chemical EOR application.