Effect of Asphaltene Characteristics on Its Solubility and Overall Stability

Abstract

Complex molecular structure, high impurity content, and self-association tendency of asphaltenes make the determination of their phase behavior very difficult. Because asphaltene phase behavior is indicative of asphaltene stability within the bulk oil, it is very important to understand its stability. Various production and flow assurance challenges related to precipitation of unstable asphaltenes can be prevented by proper comprehension of asphaltene stability. This study provides a data set on 11 different asphaltenes, which helps us to understand the complicated nature of the components of asphaltenes and crude oils that play an important role in maintaining the stability of asphaltenes. In addition to the physical and chemical characterizations, elemental analysis and ΔPS parameter, which is the indication of the solubility of asphaltenes in different solvents of the bulk oil samples, were measured and evaluated. The results of this study show that the presence of paraffinic wax and water within the crude oil samples along with impurities in the form of reservoir fines can greatly affect the stability of asphaltenes. The organometallic content of crude oil destabilizes asphaltenes, whereas a high fine content increases the stability of asphaltenes.

Performance of asphaltene stability predicting models in field environment and development of new stability predicting model (ANJIS)

“…The SARA value determined from different techniques could show significant difference in values for the same oil, therefore, may result in inaccurate stability predictions from these models (Pereira et al 2017;Kharrat et al 2007;Fan et al 2002). Furthermore, these predicting models do not take into account the factors like operational parameters such as pressure and temperature, solubility parameter of crude oil and asphaltene, polarities of resins and asphaltenes and compositional and structural characteristics of asphaltene molecule which according to previous studies play a major role in deciding the asphaltenes stability in crude oil (Gharbi et al 2017;Guzmán et al 2017;Ali et al 2021b;Punase et al 2016;Prakoso et al 2015Prakoso et al , 2018Goual and Firoozabadi 2002;Hascakir 2017;Asomaning 2003). Finally, the collection point for the testing of crude oil is also important because these SARA values may differ with respect to location due to the compositional changes occurring in crude oil during production.…”

Determination of Asphaltene Stability in Crude Oils Using a Deposit Level Test Coupled with a Spot Test: A Simple and Qualitative Approach

“… 1 The fourth way to judge asphaltene stability in crude oil is through asphaltene compositional and structural characteristics. Previous studies reported that the H/C ratio of asphaltene, 1 asphaltene solubility profile distribution, 51 , 53 asphaltene aromaticity and density, 52 polarity of asphaltene, 54 , 57 , 58 and electrical charges on asphaltenes 59 can provide information regarding the chance for asphaltene stability in crude oils. However, this method required the extracted asphaltene sample, which may lead to uncertainties in results due to asphaltene extraction methodology applied and the absence of the effect of other crude oil components such as resins, aromatics, and saturates.…”

Intermolecular Interaction between Heavy Crude Oils and Surfactants during Surfactant-Steam Flooding Process

“… 11 , 22 , 23 However, because of the molecular imbalance and the impurity content of saturate and aromatic fractions, it has recently been found that they may have also polarity. 24 Resins are known as polar fraction of the crude oil, which is soluble in lower molecular weight n -alkanes and contains less amount of metals as compared to asphaltenes. 25 , 26 Asphaltenes are the most polar and the heaviest fraction of crude oil and are insoluble in lower molecular weight n -alkanes and soluble in aromatic solvents; they contain NSO and heavy metals in their molecular structure.…”

“…1 , 11 However, for the heavy oil reservoirs, not only reservoir rocks but also asphaltenes are charged because of interactions of asphaltenes with reservoir rock. 24 , 30 , 31 Thus, in heavy oil reservoirs, the reservoir rock particles may physically be attached to asphaltene clusters and make the asphaltene surfaces charged. 20 , 32 Although this interaction is physical and not chemical, since this interaction is in micro- and nanoscales, it is irreversible.…”