Study of Asphaltene Adsorption on Kaolinite by X-ray Photoelectron Spectroscopy and Time-of-Flight Secondary Ion Mass Spectroscopy

Abstract

The interaction between asphaltenes and clay is crucial in understanding wettability changes in petroleum reservoirs and in oilsands production. In this study, we report the changes in surface properties and composition of kaolin clay as a result of exposure to solutions of asphaltenes. Adsorption experiments were conducted at 25 °C with solutions of asphaltenes in toluene at concentrations ranging from 0.05 to 5 mg/mL. The wettability of the modified kaolinite surface was characterized by contact angle measurement. Chemical composition changes of the surface because of asphaltene adsorption were assessed using time-of-flight secondary ion mass spectroscopy (ToF-SIMS), X-ray photoelectron spectroscopy (XPS), and elemental analysis. The contact angle data indicated that, upon asphaltene adsorption, the clay particles changed from water-wet to bi-wet. Both ToF-SIMS and XPS measurements indicated that the kaolinite surface was never completely covered by asphaltenes based on the concentration of Al and Si on asphaltene-treated kaolinite surfaces. ToF-SIMS analysis indicated that, with more asphaltenes covered on the kaolinite surface, the relative intensities of C 3 H 5 + /Al + and C 3 H 5 + /Si + increased and an inverse linear correlation between the contact angle and surface Si + concentration was observed. The maximum thickness of adsorbed asphaltenes, assuming complete surface coverage, was estimated to be 11 nm based on XPS depth profile results on a model silica surface, with a mean value of 3 nm. The XPS depth profile also indicated no preferential adsorption of nitrogen-or sulfur-rich species at the interface between asphaltenes and kaolinite.

A molecular dynamics investigation into the adsorption behavior inside {001} kaolinite and {1014} calcite nano-scale channels: the case with confined hydrocarbon liquid, acid gases, and water

“…The findings also conclude the wettability and dynamical properties, to be affected by confinement size of pores of reservoir rocks (Al-Quraishi and Khairy 2005;Cui et al 2003;Standnes and Austad 2000;Yuan et al 2015). A few investigations were also directed towards analysis of adsorption of organic molecules over clay (Hu et al 2014;Pernyeszi et al 1998;Wang et al 2013) (mainly kaolinite), as well as non-clay (Cooke et al 2010;de Leeuw and Parker 1998;Freeman et al 2009;Guiwu et al 2009;Keller et al 2015;Sakuma et al 2014) (mainly calcite) surfaces. In this regards, the main focus has been devoted to the {001} kaolinite or {1014} calcite structures, on the premise of holding the primary cleavage planes (Miller et al 2007;Sekkal and Zaoui 2013;Titiloye et al 1993;Zielke et al 2015).…”

Sorption equilibrium and kinetics for cyclohexane, toluene, and water on Athabasca oil sands solids

“…The increased organic solvent uptake on FS is likely due to the partitioned organic materials on FS. The morphology of the organic material on FS has been proposed to be patchy structures a few nanometers thick, so it would be readily accessible to the solvent vapour.…”

Polycardanol and Poly(cardanol‐co‐styrene): Synthesis, Characterization, and Performance as Asphaltene Flocculant

“…In terms of solubility, asphaltenes are defined as the fraction of crude oil that is insoluble in light paraffinic solvents such as n‐pentane and n‐heptane, and soluble in aromatic solvents such as toluene . Due to this amphiphilic nature, asphaltenes are considered active on the surface and are able to adsorb at the oil‐water interface and on mineral surfaces, changing the wettability and consequently decreasing oil production …”

“…[1][2] Due to this amphiphilic nature, asphaltenes are considered active on the surface and are able to adsorb at the oil-water interface and on mineral surfaces, changing the wettability and consequently decreasing oil production. [3][4][5] The characterization of asphaltenes in the solid state provides important information on their chemical structure. For asphaltenes in solution, two properties are generally established: 1) the tendency of aggregate formation in solvents, which is related to the self-association of their molecular structure and 2) interfacial activity, by the adsorption of molecules at the oil-water interface, which is related to the amphiphilic nature of these macromolecules.…”