Static Adsorption Evaluation for Anionic-Nonionic Surfactant Mixture on Sandstone in the Presence of Crude Oil at High Reservoir Temperature Condition

Abstract

Summary The application of surfactants in enhanced oil recovery (EOR) has revealed over the years various challenges that impose limitations on the successful implementation of surfactant flooding. Surfactant adsorption is one of the most important aspects that strongly dictates the feasibility of surfactant-based EOR. The effect of the presence of crude oil on surfactant adsorption and the influence of surfactant partitioning on the adsorption quantification are presented in this paper. Static adsorption experiments were conducted in this study for a surfactant mixture [alkyl ether carboxylate (AEC):alkylpolyglucoside (APG)] on sandstone rock samples in the absence and presence of crude oil. Partitioning experiments were carried out to evaluate the surfactant partitioning between the aqueous surfactant solution and the crude oil to determine the partitioning influence on the adsorption results in the presence of crude oil. The mixture’s adsorption and partitioning behaviors were studied at a fixed salinity of 32 k ppm and temperatures of 80 and 106°C. High-performance liquid chromatography (HPLC) was used in measuring the surfactant concentration throughout adsorption and partitioning tests. Rock characterization was also performed in this study using X-ray diffraction (XRD) as well as X-ray photoelectron spectroscopy (XPS) before and after adsorption with and without crude oil being present. Static adsorption outcomes displayed the adsorption of APG, AEC, and the overall mixture with and without crude oil being present, because all are having a similar increasing trend when concentration increases. However, the adsorption values were much higher when crude oil was present as compared with the adsorption values when crude oil was absent; this is because of not considering the impact of surfactant partitioning. The adsorption values (i.e., at 0.2 wt%) for both temperatures were below 2.5 mg/g in the absence of crude oil and rose to around 3.5 mg/g in the presence of crude oil. A significant amount of what was adsorbed belongs to AEC because of its increased chain-chain interactions with APG, which was evidenced experimentally in our previous work; hence, AEC is the greatest contributor to the overall surfactant mixture’s adsorption. Also, temperature had an impact on the adsorption capacity of the AEC:APG mixture, showing that APG has a greater sensitivity to temperature in comparison to AEC. The adsorption behavior of APG was found to be the opposite of AEC, where the adsorption capacity at 106°C was lower for AEC than its adsorption capacity at 80°C and vice versa for APG. The surfactant partitioning results were used to validate the surfactant adsorption outcomes in the presence of crude oil. After eliminating the partitioning effect, the surfactant adsorption isotherms in both cases of the presence and the absence of crude oil were almost identical. The results highlighted the importance of measuring surfactant partitioning, and the impact that partitioning has on the total surfactant losses during the surfactant flooding process. XRD and XPS results indicated that the change of the rock structure after adsorption when crude oil was present was attributed to the rock dissolution phenomena. It was concluded that adsorption and partitioning take place in the water/oil/rock system simultaneously and taking that into account allows for the improved and proper designing of the surfactant flooding.

Enhanced Oil Recovery in Carbonate Reservoirs Using Single Component Synthesized Surfactants under Harsh Reservoir Conditions

“…The concentrations of the surfactants in collection vials were determined from the calibration curves, which were constructed for each surfactant solution by plotting the chromatographic integral area and the surfactant concentration. 68 It should be noted that experiments involving a polymer flood were not analyzed. The dynamic retention of surfactants was then calculated using eq 8, which is based on simple material balance: 52 (8) where Γ dynamic is the surfactant dynamic retention (mg/g-rock), C 0 (ppm) is the concentration of the injected surfactant, V (L) is the total volume of the injected surfactant solution, C i (ppm) is the concentration of the surfactant solution collected at time period i, V i (L) is the volume of the collected effluent at time i, N is the number of collection vials, and m r (g) is the mass of the dry core sample.…”

Rock–Fluid Interactions of Alkyl Ether Carboxylate Surfactants with Carbonates: Wettability Alteration, ζ-Potential, and Adsorption

“…Sand rock (mainly quartz) was used as the adsorbent, the operation temperature was 106 °C, and brine salinity was 32k ppm. The highest adsorption value was about 2 mg/g-rock at 1 wt % of the surfactant but extensively increased in the presence of crude oil due to surfactant partitioning in the hydrocarbon phase. , …”

“…The highest adsorption value was about 2 mg/g-rock at 1 wt % of the surfactant but extensively increased in the presence of crude oil due to surfactant partitioning in the hydrocarbon phase. 49,50 An increased interest in anionic−nonionic surfactants during the last 10 years resulted in many publications that describe their performance under various conditions. A brief summary of published data is given in Table 1.…”

Synthesis and characterization of a novel active polymer for enhanced oil recovery

“…20 Surfactant flooding suffers from high adsorption losses in practical applications. [21][22][23] In polymer-surfactant binary systems, chromatographic separation can occur during application due to the difference in the polymer and surfactant, leading to poor application effort. 24 The substances injected in the alkaliflooding technology can inflict different degrees of damage to the formation and confer difficulty in dehydrating emulsified crude oil, indicating that the future development direction of oil flooding should focus on the alkali-free direction.…”

“…Currently, the commonly used polymer for enhanced oil recovery (EOR) is partially hydrolyzed polyacrylamide (HPAM), 18,19 which has a high viscosity loss under harsh reservoir conditions (e.g., high temperature, high salt, and strong heterogeneity), so achieving desirable development results is difficult 20 . Surfactant flooding suffers from high adsorption losses in practical applications 21–23 . In polymer–surfactant binary systems, chromatographic separation can occur during application due to the difference in the polymer and surfactant, leading to poor application effort 24 .…”