Design and Application of a New Acid-Alkali-Surfactant Flooding Formulation for Malaysian Reservoirs

Abstract

A new Acid-Alkali-Polymeric Surfactant (AAPS) flooding formulation has been developed to overcome the precipitation problems caused by the divalent metal cations prevalent with conventional ASP flooding. The acid was evaluated in an acidalkali-surfactant formulation using sodium carbonate and introducing a new polymeric surfactant derived from Jatropha oil. The effect of the new formula on IFT, viscosity, and oil recovery was studied using natural seawater having a large quantity of divalent metal cations. The tolerance of the AAPS towards natural untreated sea water was monitored for 90 days at 90 o C. No precipitations were formed with the acid additive, while precipitations were always generated without the acid. A combination of the new system was found to significantly reduce the IFT between Angsi crude oil and AAPS solution. The most outstanding feature of the AAPS formulation lies in its viscosity insensivity towards an increasing alkali concentration up to 1.2%. Core flood tests with alkali and acid concentrations of 0.6% and 1% respectively confirmed an optimum surfactant concentration of 0.6%. Using the optimum AAPS concentrations, another series of core flood were conducted by changing the injection volume. Only a small incremental recovery was obtained with AAPS slugs higher than 0.5 PV. Injection of 0.5 PV of the formulated AAPS slug followed by chase water produced an additional 18.8% OOIP over water flooding. The benefit of the new system is the use of seawater rather than softened water while maintaining the desired slug properties.

A Perspective on the Prospect of Pickering Emulsion in Reservoir Conformance Control with Insight into the Influential Parameters and Characterization Techniques

“…Figure 2 presents a trend regarding the publications coming from different regions on emulsion development for conformance control for heavy oil recovery, oil sands using steam-assisted gravity drainage and CO2 injection. Emulsions have been applied vastly in enhanced oil recovery [16][17][18] and well stimulation operations [19][20][21][22][23][24][25][26][27][28][29] successfully and have shown desirable traits needed for conformance control; for instance, emulsified acids in well stimulation have successfully acted as good diverters as well by providing plugging effect in high permeable zones while moving fluid towards low permeable zones thus delivering satisfactory permeability enhancement as needed for both carbonate and noncarbonate rocks [21,28,[30][31][32]. Figure 2 presents a trend regarding the publications coming from different regions on emulsion development for conformance control for heavy oil recovery, oil sands using steam-assisted gravity drainage and CO 2 injection.…”

“…Microemulsions utilize large amounts of surfactant concentration, making them expansive. Although microemulsions are thermally stable but are sensitive to changes in fluid content and salinity, this can alter the fluid behavior and emulsion type on the basis of dispersion medium [18,35]; this is due to having a high interfacial area. This can affect their plugging efficiency.…”

Rapid evaluation model for EOR techniques applicability of gas flooding, foam flooding and surfactant flooding based on modified fractional flow theory

“…Resemble as Eq. ( 9), virial expansion method was applied to describe the viscosity of surfactant solvent (Elraies and Tan 2010;Vargo et al 2000) and the influence of pressure on density was not considered as well. Here, the concentration of surfactant used the effective surfactant concentration.…”

Fast Evaluation Model of Surfactant Flooding Based on Modification Fractional Flow Theory

“…The basic assumptions of the fractional flow theory model are as follows: three phases are considered, namely, oil, gas, and water; flow of each phase follows Darcy's Law; displacement is an isothermal process; viscous fingering is described with Koval coefficient; when injecting by alternate displacement, the injectants are injected simultaneously at a fixed proportion; no free gas exists; no large cracks in oil reservoir or leakage of injected gas occurs; adsorption follows mass adsorption law, and the process is irreversible; and diffusion and dispersion are considered [4][5][6].…”