Changes of Asphaltenes’ Structural Phase Characteristics in the Process of Conversion of Heavy Oil in the Hydrothermal Catalytic System

Abstract

The composition of heavy crude oil from the Ashal’cha field (Volga-Ural Basin, Republic of Tatarstan) and the peculiarities of the changes of its asphaltenes’ structural phase characteristics in the model hydrothermal–catalytic system have been studied very thoroughly. It has been established that in the water vapor media the process of destruction of the heavy crude oil high-molecular-weight components with the new light fraction formation in the presence of a natural catalyst, namely, hematite, containing iron oxide and at the temperatures of 210, 250, and 300 °C respectively, takes place which has an effect on the changes in its component hydrocarbon, fractional, and structural group composition as well as in the structural parameters of its asphaltenes. As the experiments temperature increases and the water content in the reaction system decreases, the general tendency of growth the asphaltene associates aromaticity factor revealed that in turn it is accompanied by the extension (increase) of the distance between the aromatic layers and polymethylene chain fragments under the reduction of the size of associates and the number of their aromatic layers; this results from the destructive processes course, taking place along/on the most stable asphaltene heteroatomic bonds with/accompanied by further peripheral alkyl fragments breaking off, which has been confirmed by the molecular mass of the fragments above as well as destruction of vanadyl–porphyrin complexes and increase of free radicals concentration. A significant ability of asphaltene associates to immobilize their maltenes has been revealed. Within the process of oxidation cracking at the temperature of 300 °C and under the low water content in the reaction system, the increase in aromaticity and in the degree of association asphaltenes transform to carben–carboids and then to coke and are precipitated out of the oil in the solid form.

The Oil-Bearing Strata of Permian Deposits of the Ashal’cha Oil Field Depending on the Content, Composition, and Thermal Effects of Organic Matter Oxidation in the Rocks

“…However, many issues still remain unresolved. Works on finding optimal technologies aimed at increasing the efficiency of developing deposits of heavy oils and natural bitumens using thermal methods are carried out in many research centers and oil-producing companies [15][16][17][18][19][20][21][22][23][24][25][26][27]. Difficulties arising from the development of heavy oil fields are associated with two problems: first, unfavorable reservoir properties-low thermal conductivity, low permeability, and lack of reservoir energy; second, the hydrocarbon component of the bituminous reservoirs is in an inactive state [4,7,10,12,13,15,19].…”

In-Situ Heavy Oil Aquathermolysis in the Presence of Nanodispersed Catalysts Based on Transition Metals

“…An increasing number of studies have found that steam flooding of heavy oil and oil-saturated rocks results in the destruction of the weakest carbon-heteroatom bonds with detachment of peripheral fragments from resins and asphaltenes and formation of lighter hydrocarbons [1][2][3][4][5][6][7][8][9][10][11]. The destruction of asphaltenes under the steam treatment occurs primarily through the weak aliphatic sulfide bonds ( Figure 1) that are destabilized by electron-withdrawing functional groups.…”

“…Such a process initiates already at 120 • C [13]. The destruction products of resins and asphaltenes joins other fractions, which determines reduction in heavy oil viscosity and increase in heavy oil recovery [3,4,7]. The schematics of the main chemical reactions that describe the catalytic aquathermolysis process are illustrated in Figure 1.…”

“…The authors proposed the catalytic role of metal ions in the aquathermolysis process. Since then, substantial advances in catalysis have made the catalytic aquathermolysis a distinct process, and catalytic steam-based heavy oil recovery techniques has been investigated as a promising technology to recover heavy oil resources [3][4][5][6][7][8][9][10][11][12][13][14][15][16]. More importantly, this process occurs in the cheapest high-pressure reactor of all, petroleum formations [3][4][5][6].…”

Conversion of Organic Matter of Carbonate Deposits in the Hydrothermal Fluid

“…Innovative technologies for the development of hard-to-recover hydrocarbon resources represents a highly relevant topic nowadays [27][28][29]. Alternative hydrocarbon resources, such as carbonate deposits containing organic matter, are widespread in Russia, China, Jordan, Brazil, Morocco, Australia, Estonia, USA, Canada, Zaire, Italy, France, etc.…”