A literature review of asphaltene entity, precipitation, and deposition, introducing recently models of deposition in the well column

Abstract

Organic precipitations are highly sticky and hard if some asphaltenes are present. This causes a deposition problem to occur when thermodynamic conditions are suitable for sedimentation in a wide range of production processes. This range may start from the porous media around the oil well and continue to the production pipes. Asphaltene exists in many light and heavy oil reservoirs, which often causes problems in the process of crude oil production. Asphaltenes have up to hundreds of carbon molecules in its structure which will be precipitated as a result of natural pressure drop, temperature changes and oil composition changes.In natural depletion, the main cause of asphaltene precipitation is the reduction of pressure. Due to the process of oil production from the well, which is accompanied by simultaneous reduction of pressure and temperature, this molecule is deposited to the tube wall during three stages of precipitation, growth and deposition, and causes flow obstruction.The precipitated asphaltene generated in the process of oil production from the reservoir closes the well and transmission lines. In the process of exploitation, the chock valves, separators, and other equipment in the way are blocked and broken. In refineries and petrochemicals, the presence of even small amounts of asphaltene results in a significant drop in the efficiency of catalysts and other additives. Therefore, before the reactions are performed, attempts are made to remove as much of these materials as possible from oil.In this paper, scientific literature related to the chemical structure and thermodynamic behavior of the asphaltene molecule has been investigated in order to provide clear overviews of the asphaltene precipitation and deposition, and the processes that lead to its occurrence in the well. Then, the precipitation and deposition of asphaltene in the well column and its effective factors are investigated.

Analysis of the Modern State of Researches on Deposition of Asphalt-Resin Substances, Paraffin and Modeling Methods Review Part I: Precipitation of Asphaltenes

“…The recent increase in the number of scientific publications [61][62][63][64][65][66][67][68][69] devoted to a detailed analysis of various approaches to modeling RAC by world scientists proves the importance and prospects of developing improved mathematical models for predicting RAC.…”

Evaluation of Asphaltene Stability of a Wide Range of Mexican Crude Oils

“…Finally, in downstream where crude oil is refined, since instability of asphaltenes may lead to coking, fouling, and deactivation of the catalysts used in the different refining processes. 8,16 Despite the fact that crude oils own a complex composition, compounds in crude oils can be grouped into four main fractions designated as SARA: saturated, aromatic, resin, and asphaltenes. Regarding their capacity to keep asphaltene in a solubilized state, saturated compounds are considered nonsolvent, while resins and aromatics are solvents.…”

“…An important concern when processing heavy crude oils by catalytic hydrotreating/hydrocracking is sediment formation. It has been reported that during hydrotreating, the most important factors responsible for the generation of sediments are aromaticity and polycondensation of aromatics, as well as the solubility of asphaltenes in resins. − …”

Análisis comparativo de la eficiencia estabilizadora de asfaltenos del aceite de cáscara de Anacardium occidentale y productos comerciales

“…Los asfaltenos son considerados como compuestos polares, lo que es causado por los electrones de átomos como el azufre, el oxígeno y el nitrógeno (Hasanvand et al, 2018). Se ha determinado que, incluso en bajas concentraciones, la molécula de asfaltenos presenta tendencia a agregarse y precipitarse, lo que causa grandes daños en las diferentes etapas del procesamiento del petróleo, como consecuencia de obstrucciones ocasionadas por los depósitos orgánicos que producen (Guzmán et al, 2017;Hasanvand et al, 2018).…”

“…Los asfaltenos son considerados como compuestos polares, lo que es causado por los electrones de átomos como el azufre, el oxígeno y el nitrógeno (Hasanvand et al, 2018). Se ha determinado que, incluso en bajas concentraciones, la molécula de asfaltenos presenta tendencia a agregarse y precipitarse, lo que causa grandes daños en las diferentes etapas del procesamiento del petróleo, como consecuencia de obstrucciones ocasionadas por los depósitos orgánicos que producen (Guzmán et al, 2017;Hasanvand et al, 2018). La formación de depósitos de asfaltenos es un problema de importancia en la producción de petróleo, porque el depósito de asfaltenos perjudica la recuperación y la producción, al producir reducción de la permeabilidad de la roca del yacimiento y disminución del diámetro efectivo de los punzonados en la tubería de producción, lo que restringe el flujo de petróleo (Martins, Martins y Santos, 2018).…”