Application of Aromatic and Industrial Solvents for Enhancing Heavy Oil Recovery from the Ashalcha Field

Abstract

Nowadays, there is a significant increase in the share of unconventional oil reserves such as heavy and extra-heavy oils as well as natural bitumen among the total balance of extracted petroleum feedstock. In this regard, one of the most important problems is to ensure their rational production and processing and satisfaction of the increasing consumption of energy resources. This paper investigates the effect of various solvents on the upgrading of heavy oil from the Ashalcha field under thermal steam injection by means of aromatic and industrial solvents. The results suggest that the largest amount of gases is released when benzene is added to the oil from aromatic solvents (500 g/t of oil). The results of viscosity dependence on temperature and component composition showed that oil has the lowest viscosity with the addition of toluene compared to the viscosity of the original oil and the control experiment samples, whose viscosities decrease by 4 and 3.5 times, respectively, at 10 °C. The changes in the chemical group composition, especially the significant decrease of resin content in the presence of all solvents (toluene, benzene, their mixture 1:1, as well as Solvesso-150), are explained by the destruction of associated complexes of resin molecules, thereby affecting a decrease in oil viscosity. The calculation of the indices of colloidal instability showed that the control experiment oil has the lowest stability due to the high value of CII. IR spectral data have established that a significant difference between spectra of all oils is the absence of absorption bands at 1710 cm −1 , which corresponds to the vibrations of CO carbonyl groups. The use of solvents for thermal steam exposure helps to ensure a high level of energy efficiency during the application of thermal steam exposure to heavy oil and natural bitumen deposits.

Influence of Naphthenic Hydrocarbons and Polar Solvents on the Composition and Structure of Heavy-Oil Aquathermolysis Products

“…Usually, the CO carbonyl group is uncharacteristic for Ashalcha reservoir crude oil and its aquathermolysis products. 19 Therefore, the absorption band at 1710 cm −1 even in the presence of both aromatic and naphthenic solvents was not detected. The aliphaticity index rises in case of cyclohexane− tetralin−decalin due to the destruction of the carbon− hetroatom bonds in aliphatic substitutions of resins and asphaltenes.…”

“…Usually, the CO carbonyl group is uncharacteristic for Ashalcha reservoir crude oil and its aquathermolysis products . Therefore, the absorption band at 1710 cm –1 even in the presence of both aromatic and naphthenic solvents was not detected.…”

“…However, there is still no systematic approach to track the hydrogen-donating capacity of solvents, as well as the conversion processes occurring in reservoir formations. Therefore, there is a noticeable effort by scholars to discover more efficient, environmentally friendly, and cost-effective ways of in situ hydrogenation of heavy hydrocarbons that allow improvement of the quality of hydrocarbons before their extraction. − The possible alternative ways for generating hydrogen in place are introduction of naphthene aromatic compounds, carbon monoxide for implementation of the water–gas shift reaction, and injection of formic acid and formiates. Only naphthene aromatic compounds are able to directly transfer hydrogen by reduction of the corresponding compounds in a hydrothermal process.…”

A Critical Review of Reservoir Simulation Applications in Key Thermal Recovery Processes: Lessons, Opportunities, and Challenges

“…It was observed in their simulation that DME SAGD led to a higher chamber edge temperature and higher solvent recovery compared with C 4 -based SAGD . New solvents such as cracked naphtha, aromatic and industry solvents such as toluene, and benzene have been tested in the laboratory, showing positive results on improving oil production. New generation solvents such as biodiesel, switchable-hydrophilicity tertiary amines, and nanofluids were coinjected with steam to improve favorability of rock wettability and reduce interfacial tension, which may benefit oil recovery .…”

A Thermal Study on Peat Oxidation Behavior in the Presence of an Iron-Based Catalyst

“…EOR consists of a set of methods that could be applied for recovering hydrocarbons from unconventional resources [18]. EOR is classified into chemical [19,20], physical [21,22], and thermal methods [23,24] depending on the applied technique. Among these methods, thermal enhanced oil recovery methods are attracting great interest in terms of recovery and economy.…”