Investigating the Effect of Salinity on the Behavior of Asphaltene Precipitation in the Presence of Emulsified Water

Abstract

Asphaltenes precipitation and deposition is one of the main problems in the petroleum industries which has attracted the attention of many scholars. Precipitation and deposition of asphaltenes can lead to many problems in oil reservoirs such as plugging the pores of the reservoir rocks and changing the wettability of the rocks from water-wet to oil-wet. This ultimately causes a reduction or puts an end to production from reservoirs. Therefore, understanding the factors affecting the formation of asphaltenes precipitation can help us to avoid these drawbacks. Several factors including pressure, temperature, and composition changes have been studied in the literature. The effects of these parameters on the stability of asphaltenes are almost clear. However, the effects of water emulsions, which are formed during the water-based enhanced oil recovery (EOR) methods such as smart water and low salinity water flooding, on the instability of asphaltenes are still unknown and blurred. In this study, the effects of several synthetic brines which were prepared by different salts in a wide range of concentrations were investigated to understand the mechanism of ions on the instability of asphaltenes. It was found that the divalent cations have more effects on the instability of asphaltenes compared to monovalent cations due to the chelate formation. Furthermore, the presence of divalent anions in the system can hinder the effect of cations on the instability of asphaltenes.

Experimental investigation into Fe3O4/SiO2 nanoparticle performance and comparison with other nanofluids in enhanced oil recovery

“…Also, higher interactions among asphaltene molecules occurred with an increase in the number of free ions and anions in which the stability increased because the asphaltene molecules have multiple active electronegative sites such as -OH, =C=O and =N (Lashkarbolooki et al 2016). These chemical bonds strongly tend to absorb protons, and it is possible for negatively charged asphaltene molecules to be absorbed onto H + ions and become positive loads (Lashkarbolooki et al 2016;Shojaati et al 2017). As a result of low and high pH values, functional groups of asphaltene are charged and result in higher polarity and hydrophilicity that increase the stability.…”

Impact of Low Salinity Water Injection on CO2 Storage and Oil Recovery for Improved CO2 Utilization

“…Another important development in effective utilization of injected water is the addition of salts in low concentrations, in the process called low saline water (LSW) injection. Several studies observed that the injection of low salinity brine helps to achieve higher incremental oil recovery (Al Harrasi et al, 2012;Brady and Krumhansl, 2012;Nasralla and Nasr-El-Din, 2014;Shaddel et al, 2014;Shojaati et al, 2017;Yang et al, 2016). Sharma and Filoco (2000) suggested that the use of low-salinity brine, as connate fluid, alters the wettability of the rock from a water-wet to a mixed-wet surface and contributes to an increase in oil recovery.…”

Chemical study of asphaltene inhibitors effects on asphaltene precipitation of an Iranian oil field

“…In some cases, gas injections, including injection of CO 2, can disturb the chemical and thermodynamic balance of crude oil and cause precipitation of asphaltene. Of course, some key factors such as solvent type sample/ precipitant ratio and contact time cannot be ignored in the analysis of the process (David Ting et al, 2013;Ebrahimi et al, 2016;Hammami et al, 2000;Hu and Guo, 2001;Shojaati et al, 2017). Keeping the operational conditions at the level similar to the initial condition is practically impossible and is very difficult and costly work, thus effectual ways should be chosen to solve the problem.…”

“…Most of the costs are related to the production of raw materials for inhibitors. Therefore, asphaltene inhibitor should be selected with the optimum concentration (Imanbayev et al, 2017;Mao et al, 2017;Permanyer et al, 2002;Shojaati et al, 2017;Simakov et al, 2015;Smith et al, 2008). Recently researchers have shown that asphaltene acts as a weakly hydrous binder and also as a strong receiver of hydrous bands, which shows that asphaltene is a Lewis base.…”