Study of Asphaltene Solutions by Electrical Conductivity Measurements

Abstract

Les interactions des asphalt•nes avec leur environnement molŽculaire dans des solutions mod•les ont ŽtŽ ŽtudiŽes par la mesure de la conductivitŽ Žlectrique de ces solutions. Les interactions avec le n-heptane, des rŽsines, des tensioactifs, l'eau, le phŽnol et le chlorure de sodium ont ŽtŽ explorŽes. Les conclusions tirŽes de cette Žtude ont confirmŽ certaines hypoth•ses faites sur les mŽcanismes d'agrŽgation des asphalt•nes en solution, en particulier dans le cadre de la thŽorie des solutions collo•dales. STUDY OF ASPHALTENE SOLUTIONS BY ELECTRICAL CONDUCTIVITY MEASUREMENTSThe asphaltene interactions in model solutions were studied using a technique based on the electrical conductivity measurement. Interactions with n-heptane, resins, surfactants, water, phenol and NaCl were investigated. The conclusions drawn from this study confirmed previous opinions on aggregation mechanism of asphaltenes in solutions. They confirmed also the interpretation of asphaltene behaviour in terms of colloidal solution theories. CONDUCTIBILIDAD ELƒCTRICA DE LAS SOLUCIONES DE ASFALTENOSSe ha procedido al estudio de las interacciones de los asfaltenos con su entorno molecular en soluciones modelo, por la medici-n de la conductibilidad elŽctrica de Žstas. TambiŽn se han explorado las interacciones con el n-heptano, las resinas, los tensioactivos, el agua, el fenol y el cloruro de sodio. Las conclusiones que se derivan de este estudio han venido a confirmar ciertas hip-tesis establecidas acerca de los mecanismos de agregaci-n de los asfaltenos en soluci-n, y b ‡sicamente, situ ‡ndose en el marco de la teor'a de las soluciones coloidales.

A review on methods of determining onset of asphaltene precipitation

“…They used electrical and optical methods to determine the onset of asphaltene precipitation and concluded that combining these two techniques improves the interpretation of experimental results. Behar et al (1998) studied the effect of asphaltene concentration in solutions of asphaltenes in nitrotoluene and THF by conductivity measurements. They repeated their experiments on solutions of asphaltenes in nitrotoluene in the presence of resins.…”

Dynamic asphaltene deposition control in pipe flow through the application of DC potential

“…It is observed that destabilization of colloidal asphaltene in oil production systems may occur if the surface charge and the resulting attraction forces between adsorbed resins and asphaltenes are disturbed (Leontaritis 1989;Alkafeef 2001). Later works of Fotland and Anfindsen (1996) and Behar et al (1998) on electrical conductivity of asphaltene helped in understanding their molecular association phenomena in solution phase, while works of Igor and Aleksander (2010) on electrical conductivity of solid asphaltenes showed that asphaltenes in solid state behave like semiconductors, conductivity increasing at higher temperature, possibly due to structural phase transition.…”

Review of Asphaltenes in an Electric Field

“…59 Electrical conductivity studies showed that resins can neutralize part of the asphaltene charges by adsorbing on their surface. 65 The stability of asphaltenes in petroleum fluids can also be disrupted by several other stimuli, including pressure, temperature, concentration, and composition of the injected solvents, e.g., steam, CO 2 , nitrogen, methane, etc. However, the process of asphaltene aggregation and precipitation is more sensitive to pressure than other thermodynamic and process parameters.…”

“…87,95 However, in nitrotoluene, resins were shown to decrease the DC conductivities of asphaltene clusters. 65 In a heptane/toluene mixture, resins have a propensity to aggregate with asphaltene, decrease the conductivity, and enhance their stability in the mixture. 59 3.4.…”

“…The extent by which resins affect asphaltenes stability depends on their dielectric properties . Electrical conductivity studies showed that resins can neutralize part of the asphaltene charges by adsorbing on their surface …”