Experimental Investigation of the Brine Effect on Asphaltene Precipitation and Deposition during Water Injection in Porous Media Using Static and Dynamic Systems

Abstract

Asphaltene precipitation and deposition in porous media damages formation by reducing permeability and altering wettability, resulting in a significant reduction in reservoir oil production. Although the effects of some factors such as temperature, pressure, and composition have been studied over time, the effects of others, such as emulsified brine, remain uncertain and the available data in this area is limited. Most importantly, the effect of brine injection on deposition has never been studied in previous research. In this study, a number of systematic experiments were designed and conducted to investigate the effect of the aqueous phase. Several variables, including the water content, salt type, and salt concentration were studied in both the static and dynamic systems, and the evidence of consistent changes in asphaltene precipitation and deposition has been obtained. The results revealed that when the water amount reaches 50 wt %, asphaltene precipitation increases close to 10 wt %. However, as the amount of water increased, the intensity of asphaltene precipitation decreased. Furthermore, various salts have shown different behaviors in the static system and dual effects have been observed with increasing concentration. The optimum concentration of different salts was found to be between 25 000 and 40 000 ppm, MgCl2 producing the most asphaltene precipitation and KCl producing the least. MgCl2 at a concentration of about 40 000 ppm resulted in the precipitation of 7.8 wt % asphaltene and while this was 6.4 wt % for KCl 25 000 ppm. Also, for these salt concentrations, the interfacial tension reached 20.5 and 22.5 mN/m, respectively. Although the presence of water in the flooding system reduced the permeability up to 60% by depositing the asphaltene, unlike the static test, the presence of salt had no significant effect on the permeability reduction.

Ionic Liquid Application To Prevent Asphaltene Precipitation and Deposition during Water-Based EOR Techniques

“…Doryani et al indicated that divalent cations intensify the asphaltene precipitation more than monovalent cations. An identical result is reported by Shahsavani et al However, Alizadeh and Soltani Soulgani concluded that asphaltene precipitation does not necessarily intensify in the presence of divalent cations since Ca 2+ and Na + showed a similar effect on asphaltene instability.…”

“…However, with a further increase in salinity to 45,000 ppm, asphaltene precipitation reduced. In 2021, Alizadeh and Soltani Soulgani observed that the asphaltene precipitation increases with an increase in water content, as has been reported by Asaadian et al . Furthermore, their studies on salt concentration revealed that the amount of asphaltene precipitation increases with an increase in salinity to the range of 25,000 to 40,000 ppm and then decreases.…”

“…Although Shojaati et al 30 and Alizadeh and Soltani Soulgani 31 observed that the maximum asphaltene precipitation takes place at the salinity of 15,000 and 20,000− 45,000 ppm, respectively, the observed trend in this study is consistent with the results reported by them. 30,31 Furthermore, the results indicated that the asphaltene absorption at the water−oil interface is less than that observed for deionized water at high water salinity of 80,000 ppm. In other words, high water salinity leads to more asphaltene stabilization in the presence of water.…”

“…Additionally, the IFT measurement was conducted to confirm the results of the indirect method. 31 The results of emulsion formation, aging time, and centrifugation process illustrated that the emulsion phase volume increases with an increase in water salinity to the range of 20,000 ppm, while with a further increase in salinity, the emulsion phase volume decreases so that the emulsion volumes at the salinity of 80,000 ppm are less than those in the presence of deionized water (see Figure 11).…”

Critical Review of Underlying Mechanisms of Interactions of Asphaltenes with Oil and Aqueous Phases in the Presence of Ions

“…The interactions between fluids as a function of fluids composition, strongly affect the recovery factor of low salinity water flooding. Alizadeh and Soulgani investigated the effect of low salinity water injection on asphaltene precipitation in an oil (23.51 °API) at 25 °C. The asphaltene content was 6.5 wt %.…”