B. P. Tumanyan

Conversion Processes for High-Viscosity Heavy Crude Oil in Catalytic and Noncatalytic Aquathermolysis

We have conducted experiments on noncatalytic and catalytic aquathermolysis of high-viscosity heavy crude oil from the Ashal’cha field (Tatarstan) in the presence of a crude oil-soluble nickel- and cobalt-containing catalyst, a proton donor, and a rock-forming mineral. We have identified the characteristic features of the change in the constituent composition, the hydrocarbon composition, and the fractional composition, the rheological properties of the crude oils, the average molecular weight of the asphaltenes for catalytic and noncatalytic conversion processes. For catalytic aquathermolysis, we established significant de novo formation of light 70°C-250°C fractions (by 23 wt.%), n-alkylbenzenes, an increase in the oil content by a factor of 1.3, a decrease in the resin content by a factor of 1.7, and a decrease in the viscosity by 98 rel.%. The major difference between the conversion of crude oil in the presence of the catalyst and the proton donor involves activation of degradation reactions at C–C, C–N, C–O, C–S bonds and blocking of polymerization reactions and accordingly less coke formation. We observed sorption of the catalyst components on rock.

Promising Aspects of Heavy Oil and Native Asphalt Conversion Under Field Conditions

Heavy oils and native asphalt commercial field development is concerned with research on different issues, refer to production, transportation and processing. Investigation on the possibility of heavy oils and native asphalt conversion under field conditions, including downhole treatment, in order to decrease crude oil viscosity is one of the promising research trends in this field. The stated conversion is feasible under thermolysis and aquathermolysis processes, among others. Overwhelmingly important and relevant objective is determination of common factors and development of scientific basis of the mentioned processes.

Thermodynamic parameters of conversion reactions of some heavy oil components under the action of steam and heat

The mechanism of the reactions of conversion of heavy oil components, viz., heteroatomic compounds and polycyclic aromatic hydrocarbons, under conditions of steam and thermal action on the oil reservoir is studied. Based on the calculation of the thermodynamic parameters of the reactions, conclusions are drawn regarding the feasibility of the reactions and the primary directions of conversion of heavy oil components at the steam and thermal action temperature. The possibility, in principle, of occurrence of hydrogenolysis, hydrogenation, and hydrocracking in the presence of such hydrogen donors as polycyclic naphthenic-aromatic hydrocarbons and formic acid in the reaction system is demonstrated.

Stability of Petroleum Asphaltene Fractions in Model Hydrocarbon Systems

The effect of synthetic and natural surfactants on the stability of solutions of asphaltenes of Ashal’cha crude oil (Tatarstan) in toluene is studied. The mechanism of interaction of the surfactant having various molecular structures with asphaltene aggregates is proposed and the effect of the surfactant structure on the behavior of the surfactant as a flocculation inhibitor or initiator is studied. It is shown that the effectiveness of the inhibitors differ when they are added to solutions of wide asphaltene fraction and solutions of A1 and A2 asphaltenes. The effect of the structure of the alkyl part of the bioadditive molecule on its effectiveness as a flocculation inhibitor is described. It is found that the stability of A1 asphaltene solutions increases markedly (threefold) upon addition of crude oil wax and that this effect is absent in solutions of A2 asphaltenes and wide fraction. It is proved that the sensitivity of A2 asphaltenes to addition of wax is determined by the excess of petroleum ether used for separation of wide asphaltene fraction: presence of immobilized resins in A1 asphaltenes produces a significant effect on the change in stability of A1 asphaltene solutionsupon addition of wax.

Change in the Hydrocarbon and Component Compositions of Heavy Crude Ashalchinsk Oil Upon Catalytic Aquathermolysis

A physical model has been developed for the aquathermolysis of heavy crude oil from the Ashalchinsk oil field at 250°, 300°, and 350°C. Nickel and cobalt carboxylates were used as oil-soluble catalyst precursors. In the presence of a hydrogen proton donor at 300°C, the oil content was found to rise considerably and the resin content was found to decrease by a factor of 1.8, which leads to a decrease in crude oil viscosity by 91% and a decrease in density from 960 to 933 kg/m3. The hydrocarbon composition of the liquid aquathermolysis products was studied by chromate-mass spectrometry. The average molecular weight of the asphaltenes was determined by matrix-assisted laser desorption/ionization (MALDI) spectrometry. The maximum disproportionation of the hydrocarbons into n-alkanes, alkylcyclohexanes, and alkylbenzenes occurs at 300° and 350°C. The composition of the hydrogen proton donor (tetralin) conversion products at these aquathermolysis temperatures was determined.

Effect of Vegetable Oils on Tar Coking

Tar coking in the presence of vegetable oils is studied. Use of vegetable oils as tar additives during coking is shown to have no significant effect on the total yield of vacuum distillates from the liquid coking products. However, their use could change the quantitative ratio of the obtained distillates.

Synthesis of Hydrocarbon Resins by Thermal Polymerization of Unsaturated Compounds of Pyrolysis Fractions

Hydrocarbon resins were synthesized by thermal polymerization of the olefinic compounds of liquid pyrolysis products (the C9+ fraction, heavy tar). The hydrocarbon resins were characterized by 1H NMR spectroscopy, MALDI spectroscopy, and gel permeation chromatography. The effect of temperature, reaction time, feed composition, and solvent content on the yield, molecular weight, color, and molecular structure of the hydrocarbon resins was investigated. It was shown that addition of the C9+ fraction to heavy tar increases the polymer yield while reducing the content of aromatic fragments in its structure.

Applied Aspects of the Study of Thermodynamic Parameters of Oil Disperse Systems

For intensification of oil refining without using secondary processes, thermodynamic parameters of gas condensate and residual fuel oil blends were calculated from experimental investigations involving inverse gas chromatography. Apparently, from thermodynamic parameters of gas condensate and residual fuel oil blend, it is possible to determine the optimal ratio of the components for increasing the yield of light fractions. It is likely that the new colloidal structure of the blend of the disperse system (residual fuel oil) with the homogeneous system (gas condensates) forms via formation of a semicolloidal system followed by restructurization due to intermolecular interaction and dissolution processes.

Stability of Real Asphaltene-Containing Systems in Presence of Bioadditives

The influence of synthetic surfactants and vegetable oils and their derivatives on the stability of Ashal’cha (Tatarstan) crude oil asphaltenes against precipitation is studied by methods of titration with n-heptane and determination of the quantity of the precipitate separated by reducing the dissolving power of the dispersion fluid. It is found that bioadditives containing –COOH and –OH groups in the molecule enhance crude oil stability most effectively. It is proved that loss of crude oil stability occurs upon injection of certain additives containing several polar groups in the molecule, which facilitates formation of bonds between asphaltene aggregates. In experiments simulating compounding of heavy and light paraffinous crude oils it is shown that addition of surfactants to crude oil blends, rather than to heavy crude, is most effective.