Method for operating a plant of hydrocarbons containing organo-sulfur compounds by means of a thermo-cinetic model and a compositional tank simulation

Abstract

A method for determining an amount of hydrogen sulfide produced by a phenomenon of aquathermolysis induced by a thermal process, such as steam injection.On the basis of a compositional representation of the hydrocarbons, an elementary reaction scheme is defined that is representative of a material balance for the element sulfur, as well as a system of reactions representative of the aquathermolysis reaction. Then a kinetic model is constructed taking into account the reaction scheme, the system of reactions, atomic balances relating to each of the reactions and relating at least to the sulfur, carbon and hydrogen atoms. Then a thermodynamic model is constructed and the resultant thermokinetic model is calibrated on the basis of experimental measurements. Finally, an amount of hydrogen sulfide is determined by performing a compositional reservoir simulation taking into account the resultant calibrated thermokinetic model.Application notably to the exploration and exploitation of oil deposits, for example.

Description

[0001]The invention relates to the field of oil exploration, and more particularly the field of exploitation of a deposit of hydrocarbons containing organosulfur compounds, by a thermal process such as a steam injection process.[0002]During the exploitation of reservoirs of heavy crudes by a steam injection process, a phenomenon of aquathermolysis occurs, which may generate hydrogen sulfide (H2S). In fact, this type of reservoir may often have high sulfur contents. The thermal processes make it possible, by supplying calories and raising the temperature, to reduce the viscosity of the heavy crudes and thus make them producible.[0003]Aquathermolysis is defined in the present description as a set of physicochemical reactions between rock impregnated with crude oil (or with bitumen) and steam, at temperatures between 200° C. and 300° C.[0004]Hydrogen sulfide is a gas that is both extremely corrosive and highly toxic, or even lethal above a certain concentration. Thus, predicting the co...

AI Technical Summary

Benefits of technology

This patent text relates to a process for extracting heavy crude oil from reservoirs using steam injection. The process can produce hydrogen sulfide, which is a corrosive and toxic gas. By predicting the concentration of hydrogen sulfide in the gas produced, the process can be optimized and the risk of dangerous emissions can be minimized. The text also suggests that the process can be used to predict the variations in the composition of the oil in the reservoir, which can help to improve the quality of the oil produced. This information can be useful for adapting the production equipment and optimizing the operating conditions.

Problems solved by technology

However, this scheme cannot be used in a reservoir simulation.

However, this model has a number of drawbacks.

In fact, application of this method shows that the stoichiometric coefficients derived on the basis of the reaction scheme for sulfur are unable to reproduce the results observed in the laboratory, notably the variations in mass of the SARA fractions and H2S over time.

Moreover, the kinetic model developed in this application, based solely on the element sulfur, cannot respect the average atomic balances of the atomic elements, other than sulfur, making up the pseudo-molecules representing the various SARA fractions, namely carbon (C), hydrogen (H) and oxygen (O).

These limitations have the result that the reaction scheme described in application FR 3002969 (U.S. Ser. No. 14 / 200,682) does not allow experimental data to be incorporated, such as the results of elemental analyses performed in the laboratory, which might, however, act as constraints to be respected by linking the number of atoms of the constituent elements of each of the pseudo-constituents to its number of carbon atoms.

Moreover, the kinetic model of application FR 3002969 (U.S. Ser. No. 14 / 200,682) does not allow the element oxygen to be taken into account, which prevents prediction of the evolution of water (H2O) and carbon dioxide (CO2) during the aquathermolysis reactions.

However, H2O is an essential reactant of the aquathermolysis reactions, without which the reactions cannot take place.

Now, as water is not incorporated in the compositional reaction scheme, like numerous chemical species, a simple mass balance for the reactions of the model cannot allow a stoichiometric coefficient suitable for the saturates to be determined.

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