RU2742651C1 - Method for determining hydrocarbon fluid composition - Google Patents

Abstract

FIELD: oil industry.

SUBSTANCE: invention relates to a method for analyzing complex hydrocarbon fluids and can be used for analyzing oil and gas condensate. The invention relates to a method for determining the composition of hydrocarbon fluid, which comprises determining the density of hydrocarbon fluid and determining the composition of hydrocarbon fluid by gas chromatography combined with time-span mass-analyzer for hydrocarbon fluid densities of 0.85 g/ml or less combined with a flame ionization detector or with a quadrupole mass-analyzer for hydrocarbon fluid densities greater than 0.85 g/ml but not more than 0.96 g/ml. The invention also relates to a variant of a method for determining the composition of hydrocarbon fluid and to variants of systems for selecting a hydrocarbon fluid composition method.

EFFECT: technical result is increase in accuracy of determining the composition and producing a hydrocarbon fluid fingerprint, which in turn leads to an increase in the degree to which hydrocarbon fluids differ relative to each other.

36 cl, 12 dwg, 5 tbl, 4 ex

Description

The invention relates to a method for analyzing complex hydrocarbon fluids and can be used for the analysis of oil and gas condensate.

The data on the composition of hydrocarbon fluids are used, in particular, to monitor the development of hydrocarbon deposits, to link to the development target (oil and gas bearing formation) of the field, to assess the dynamics of changes in fluid properties during the development of reserves and in the process of stimulating the formation by means of enhanced oil recovery methods. High accuracy in determining the composition of the hydrocarbon fluid is especially important when building models for the miscibility of hydrocarbon fluids from different reservoirs, when determining the contribution of the fluid of each reservoir to the composition of the well product, if production from them occurs together. At the same time, it is necessary to ensure high accuracy in determining the composition of the fluid or a set of data that reflects the composition of the fluid (the so-called "fingerprint" is a set of parameters that uniquely characterize a hydrocarbon fluid sampled from a particular oil and gas reservoir, i.e., individualizing parameters of the fluid composition) for its recognition in a mixture of two or more different hydrocarbon fluids.

The main method for determining the composition of hydrocarbon fluids currently used is gas chromatography combined with a flame ionization detector (FID / FID). Gas chromatography combined with a quadrupole mass analyzer (GC-MS) or with other types of mass analyzers (detectors), for example, a time-of-flight mass analyzer (GC-TOF), is also widely used.

The principles of detecting compounds that make up a hydrocarbon fluid are different for different analyzers, and therefore their resolution also differs.

The principle of operation of the PID is based on measuring the dependence of the electrical conductivity of an ionized gas on its composition. The quadrupole mass analyzer uses focusing of ionized particles in direction and velocity by applying an electromagnetic field. The principle of operation of the time-of-flight mass analyzer is the difference in the velocities of ion movement depending on their masses in a field-free space. It is known from the prior art that using a time-of-flight detector can measure a wide range of masses, tens and hundreds of thousands of atomic units [N.A. Klyuev, E.S. Brodsky. Modern methods of mass spectrometric analysis of organic compounds. Grew up. chem. g. (Zh. Ros. Chem. Society named after DI Mendeleev), 2002, vol. XLVI, No. 4, pp. 57-63], it is noted that the measurement of the masses of large molecules is an advantage of the method [M. Tokarev. What is mass spectrometry and why is it needed. https://chromatec.ru/upload/iblock/761/7615ae44b53a73f5cd42369482c680f1.pdf]. Therefore, the time-of-flight analyzer is mainly used for the determination of heavy molecules. The high accuracy of determining the composition in a wide range of masses using this analyzer is associated with a high scanning speed, regardless of the mass range [J. Binkley, M. Libarondi. Comparing the Capabilities of Time-of-Flight and Quadrupole Mass Spectrometers. LC GC. Solution for separation scientists. 2010. Vol. 8, Iss. 3, p. 28-33]. The same source also notes that for a quadrupole mass analyzer, the wider the scanning range (mass range), the lower the signal registration / detection rate. Those. for a quadrupole mass analyzer, increasing the mass range should decrease the number of detected signals and, accordingly, the accuracy of determining the composition.

There is a known method for analyzing samples (patent RU 2707621, publ. 28.11.2019, IPC: E21B 49/10), which includes the choice of an analytical method, analysis of a set of calibration oils, analysis of samples of calibration oils for a chemical composition using a sensor system, when This data spectrum contains a set of responses from each sensor element, with each element responding to a set of specific types of components. This method makes it possible to determine the viscosity of bitumen and heavy oil or other bulk properties of oil or bitumen in reservoirs, to conduct geochemical analysis of key oil components. In this case, the choice of the analytical method is based on the assessment of at least one type of chemical compound or molecular weight difference based on the composition of the oil or on the identification and control of geochemical processes or properties that control the viscosity of the oil. A common feature with the claimed invention is the ability to analyze a sample by gas chromatography or gas chromatography-mass spectroscopy to determine the chemical composition.

However, the known method is aimed at determining the viscosity, in particular, on the basis of data on the chemical composition, and does not allow determining the composition of hydrocarbon fluids with high accuracy, for example, for constructing miscibility models.

There is a known method for analyzing a complex mixture containing hydrocarbons (patent RU 2341792, publ. 20.12.2008, IPC: G01N 27/62, G01N 30/72), according to which, by means of gas chromatography-mass spectrometric analysis of hydrocarbon samples from oil wells, a fingerprint of the investigated fluid and use the resulting fingerprints of various mixtures to predict the origin and properties of one of the hydrocarbon mixtures. In this case, various methods of ionization of a hydrocarbon fluid are used to improve the accuracy of determining the composition of the fluid and obtaining its fingerprint. A common feature with the claimed method is the determination of the composition of the hydrocarbon fluid by gas chromatography.

However, the known technical solution does not take into account the principle of operation of the detector itself, the properties of the analyzed fluids (in particular, the density characteristics, the fractional composition of the hydrocarbon fluid) and the effect of these parameters on the resolution of the detector. This leads to a decrease in the detection accuracy when using only one type of detector to determine the composition and obtain a fingerprint of a hydrocarbon fluid when analyzing oils of various compositions.

There is a known method of using oil fingerprints to determine the quantitative contribution of each fluid while simultaneously producing from several reservoirs (MA McCaffrey, DK Baskin. Unconventional Resources Technology Conference, 2016, URTeC: 2460348), in which to obtain a fingerprint, the composition of oil is determined by gas chromatography using PID. A common feature with the claimed method is the use of the gas chromatography method combined with an ionized particle detector (namely, FID) to determine the composition and obtain a fingerprint of a hydrocarbon fluid.

However, it is known that the resolution of the FID depends on the conductivity of the gas, which in turn depends on the concentration of ions in it. In this case, the concentration of ions in the flames of higher hydrocarbons can be higher compared to light hydrocarbons. Accordingly, the higher the concentration of ions, the higher the sensitivity and accuracy of detecting ionized particles, and, accordingly, determining the fingerprints of each fluid. The known method does not take into account the properties of hydrocarbon fluids, the dependence of the properties and composition of hydrocarbon fluids, which directly affects the accuracy of obtaining a fingerprint of a hydrocarbon fluid sample under comparable conditions for gas chromatography. In this connection, the known method does not ensure the accuracy of determining the composition and obtaining fingerprints of hydrocarbon fluids of various compositions and densities.

A known method for determining the composition and properties of the formation fluid based on the geological characteristics of the formation (patent RU 2720430, publ. 04/29/2020, IPC: E21B 49/08, G06F 17/18, G01N 33/26), in which the composition and properties of the fluids are determined by the methods of physicochemical analysis, which are designed to determine the list of parameters of the composition and / or properties of formation fluids, which ensure the distinguishability of the fluids of the studied pair of formations, using the database and the geological characteristics of the formations.

However, the known method makes it possible to ensure the distinguishability of fluids when determining the composition and / or properties of fluids using data on the geological characteristics of the formation, but does not take into account the properties of the fluids themselves when determining the composition and does not allow improving the accuracy of determining the composition of hydrocarbon fluids.

Also known from RU 2720430 is a computer-readable medium for use in the known method. However, the program code of the computer program, which is stored on a known computer-readable medium, does not make it possible to determine a specific method of gas chromatography combined with an ionized particle detector and to provide an increase in the accuracy of determining the composition of this fluid.

The closest analogue (prototype) is a method for determining the fractional composition by gas chromatography (GOST R 56720-2015, "Petroleum products and stable gas condensate"). According to the specified method, the oil product sample is analyzed on a gas chromatograph with a flame ionization detector in the mode of programming the temperature of the column thermostat. A common feature of the known method with the claimed one is the use of a gas chromatograph equipped with a flame ionization detector to determine the composition of a hydrocarbon fluid (gas condensate).

However, as mentioned above, the resolution (in particular, the number of recorded signals) of the FID depends on the gas conductivity, which directly depends on the composition of the hydrocarbon fluid under comparable gas chromatography conditions and, accordingly, the properties of the analyzed hydrocarbon fluids, which is not taken into account in the known method. Due to the fact that the known method does not take into account the relationship between the properties of the hydrocarbon fluid and the principle of operation of the detector, this does not allow for high accuracy in determining the composition and obtaining a fingerprint of the hydrocarbon fluid.

The technical result of the invention is to improve the accuracy of determining the composition and obtaining a fingerprint of a hydrocarbon fluid, which in turn leads to an increase in the degree of difference between hydrocarbon fluids relative to each other.

The technical result is achieved by implementing a method for determining the composition of a hydrocarbon fluid, including determining the density of a hydrocarbon fluid, determining the composition of a hydrocarbon fluid by gas chromatography, combined with a time-of-flight mass analyzer in the case of a hydrocarbon fluid density of 0.85 g / ml or less, combined with a flame ionization detector or with a quadrupole mass analyzer in the case of values of the density of the hydrocarbon fluid above 0.85 g / ml, but not more than 0.96 g / ml.

The technical result is achieved by preliminary determination of the density of the hydrocarbon fluid. The density of oil as a mixed hydrocarbon fluid makes it possible to preliminarily estimate its fractional composition: the more hydrocarbons of light distillate fractions (which contain hydrocarbons with a lower molecular weight and, accordingly, with a smaller amount of isomers) are included in the hydrocarbon fluid, the lower, respectively, the density of this fluid. Thus, the oil density of 0.85 g / ml corresponds to the content of light fractions of hydrocarbons of the order of 40%. Within the framework of the claimed invention, when using the method, it was found that when using the gas chromatography method, the accuracy of determining the composition of a hydrocarbon fluid with a content of light fractions of hydrocarbons of 40% or more (i.e., at a density of a hydrocarbon fluid) of 0.85 g / ml or less) increases, namely when combined with a time-of-flight mass analyzer. At a density above 0.85 g / ml, but not more than 0.96 g / ml, the content of heavy hydrocarbon fractions increases, and the content of isomers with the same molecular weight also increases. Instead, when using the claimed method, it was also found that when using the gas chromatography method, the accuracy of determining the composition of the hydrocarbon fluid increases when the density of the hydrocarbon fluid exceeds 0.85 g / ml, but not more than 0.96 g / ml (i.e., when the content light fractions less than 40% and an increase in the mass range of hydrocarbons) precisely when it is combined with a quadrupole mass analyzer or with an FID. An increase in the accuracy of determining the composition and obtaining a fingerprint of a hydrocarbon fluid is due to the fact that, as mentioned above, detectors of ionized particles differ in their principle of operation. Differences in the principle of operation depending on the composition of the analyzed liquids, namely, on the amount of light and heavy fractions of hydrocarbons in the composition of the fluid, lead to the detection (receipt) of a different number of signals. The greater the number of signals received when determining the composition of a fluid by gas chromatography combined with an ionized particle detector, the higher the accuracy of determining the composition of this fluid, under the same or comparable conditions of gas chromatography and ionization.

The time-of-flight detector is used, as indicated above, to determine the composition over a wide range of masses, mainly for the detection of heavy molecules. Within the framework of the claimed invention, it is shown that the specified detector does not provide high accuracy in determining the composition of a complex hydrocarbon fluid (oil) due to the presence of a large number of individual isomers, the mass of which is the same. With an increase in the number of carbon atoms in the composition of hydrocarbons (i.e., with an increase in their molecular weight and, accordingly, the density of fluids that include such hydrocarbons), the number of isomers whose ion masses are the same also increases. Hydrocarbon fluids with a density higher than 0.85 g / ml are characterized by a low content of hydrocarbons with a low molecular weight (light hydrocarbon fractions) - less than 40%, and an increase in the content of hydrocarbons with a higher molecular weight. Determination of isomers will be provided only due to the production of fragment ions during ionization, i.e. there will be only one possible mechanism for the detection of hydrocarbon isomers (the detection of fragments (fragment ions) contributes to the identification of compounds that are part of the hydrocarbon fluid, since the composition of each fragment is unique). Thus, with an increase in the molecular weight of hydrocarbons in the composition of the fluid (respectively, with an increase in the density of the fluid), the number of signals received at the detector will decrease, and accordingly, the accuracy of determining the composition of hydrocarbon fluids with such a density for this detector decreases.

In this case, ions of isomers, having the same molecular weight, can have significant differences in structure, for example, in the absence of symmetry of the geometric configuration of molecules, and, accordingly, have different dipole moments. This leads to differences in their behavior in the electric field, which is created in a quadrupole mass spectrometer. With an increase in the molecular weight of hydrocarbons (respectively, with an increase in the density of fluids, which include such hydrocarbons), the effect of a change in the structural configuration of a compound on its dipole moment increases. A decrease in the symmetry of molecules leads to an increase in vibrations, which are associated with changes in the dipole moments of molecules, which makes it possible to detect ions of hydrocarbon isomers with an increase in molecular weight.

For hydrocarbon fluids with a density above 0.85 g / ml, an increase in the molecular weight of hydrocarbons that are part of their composition is characteristic. As a result, for fluids of the specified density, more peaks in the chromatogram (signals) are obtained, i.e. leads to an increase in the accuracy of determining the composition of a hydrocarbon fluid by gas chromatography combined with a quadrupole mass analyzer. With a decrease in the molecular weight of hydrocarbons, i.e. a decrease in the density of hydrocarbon fluids, in which they are included, there will not be such significant changes in the symmetry of molecules, which leads to a decrease in the number of received signals and a decrease in the accuracy of determining the composition for this method.

It was considered above that the resolution of the FID can also increase with increasing ion concentration, which is higher in higher hydrocarbon flames. Those. The resolution (number of received signals) of this detector is lower for light hydrocarbons than for heavy hydrocarbons. Due to the fact that the resolution of the FID depends on the conductivity of the flame, a larger dipole moment of the molecules with a decrease in their symmetry (respectively, the ions of these molecules) can also affect an increase in the accuracy of determining the composition of hydrocarbon fluids with a density higher than 0.85 g / ml, in the composition of which includes hydrocarbons with high molecular weight, by gas chromatography, combined with FID.

Thus, when determining the composition of hydrocarbon fluids with a density of more than 0.85 g / ml (which is characterized by an increase in the molecular weight of hydrocarbons that are part of their composition), a larger number of signals are obtained and, accordingly, an increase in the accuracy of determining the composition is provided when using the gas chromatography method combined with a quadrupole mass analyzer or with a flame ionization detector. While for hydrocarbon fluids with a density of 0.85 g / ml or less, which are characterized by a significant content of low molecular weight hydrocarbons, a greater number of signals and, accordingly, an increase in the accuracy of determining the composition is provided when using the gas chromatography method, combined with a time-of-flight detector.

The upper value of the density in the claimed method is due to the density of hydrocarbon fluids, the compositions of which were determined in practice by gas chromatography. For oils with a density above 0.96 g / ml, a high content of resinous-asphaltene components is characteristic, which, when heated, pass into a plastic state, and at temperatures above 300 ° C decompose with the formation of gaseous and liquid substances and a solid residue - coke, i.e. ... determination of the composition of such oils (hydrocarbon fluids) by gas chromatography is difficult.

The lower density value is determined by the minimum density of the hydrocarbon fluid (i.e., liquid hydrocarbon mixture). For oil, the minimum density is 0.73 g / ml. For gas condensate - 0.7 g / ml. Hydrocarbon fluids with a density below 0.73 g / ml contain a large amount of low molecular weight hydrocarbons, the evaporation of which can lead to an incorrect determination of both the density of the fluid itself and its composition due to losses due to the evaporation of hydrocarbon compounds. Determination of the density and composition of lower density hydrocarbon fluids according to the claimed method is possible with the exclusion of evaporation losses of low molecular weight hydrocarbons. In this case, they are limited only by the physical state of the fluid (liquid), as well as by the limitations of the gas chromatography method itself.

Determination of the density of the hydrocarbon fluid may include determining the number of hydrocarbon fluid samples for sampling based on the established and recorded relationship between the number of hydrocarbon fluid samples for sampling, which is sufficient to determine the composition and properties of this fluid, and the permeability of the hydrocarbon reservoir, sampling the hydrocarbon fluid from the well, that opened the hydrocarbon deposit, determination of the density of the hydrocarbon fluid of each sample, determination of the average density of the hydrocarbon fluid.

Determination of the number of samples depending on the permeability of the formation allows to increase the accuracy of determining the range of values of the density of the hydrocarbon fluid of the given formation and its average density. A more accurate value of the density of the hydrocarbon fluid will make it possible to determine its composition by the method, according to the claimed method, which will ensure the achievement of the technical result.

The achievement of the technical result is also ensured by the implementation of the method for determining the composition of the hydrocarbon fluid, including the determination of the fractional composition of the hydrocarbon fluid, the determination of the composition of the hydrocarbon fluid by gas chromatography, combined in the case of the content of light hydrocarbon fractions in the hydrocarbon fluid of 40% or more with a time-of-flight mass analyzer , and if the content of light fractions of hydrocarbons in the composition of the hydrocarbon fluid is less than 40% with a flame ionization detector or with a quadrupole mass analyzer.

Preliminary determination of the quantitative content of light and, accordingly, heavy hydrocarbon fractions in the composition of the hydrocarbon fluid makes it possible to determine the composition of the fluid by gas chromatography, combined with an ionized particle detector, which will ensure the achievement of the technical result.

Hydrocarbon fractions differ from each other in density (which depends on the nature of the hydrocarbons that make up the fluid) and boiling range, i.e. boiling points of hydrocarbons that are part of them. Light distillate fractions of petroleum (gasoline and naphtha), for example, are a mixture of light hydrocarbons up to C ₁₁ H ₂₄ and C ₁₄ H _30, respectively. The boiling point at atmospheric pressure of light fractions is up to 180 ° C-200 ° C. Within the framework of this invention, hydrocarbon fractions with a boiling point up to and including 180 ° C are referred to as light fractions.

The relationship between the principle of operation and the composition of the hydrocarbon fluid, in particular the fractional composition, as well as the effect on improving the accuracy of determining the composition of the hydrocarbon fluid by gas chromatography, combined with various types of detectors, is described above.

An increase in the accuracy of determining the composition by gas chromatography, combined with a time-of-flight detector, with a content of light hydrocarbon fractions of 40% or more, is believed to be related to the following. First, the light hydrocarbon fractions contain significant amounts of monocyclic hydrocarbons. With an increase in the molecular weight of hydrocarbons, the composition contains bicyclic and polycyclic hydrocarbons. The number of isomers of cyclic hydrocarbons is less than the number of isomers of n-alkanes of the same molecular weight. Second, during ionization, heavy hydrocarbons also form smaller fragmented ions with a lower molecular weight; accordingly, with a decrease in the molecular weight of ions, the effect of the structure on the dipole moment will decrease and an increase in the symmetry of ions will lead to a decrease in vibrations that are associated with changes in the dipole moments , which will reduce the accuracy of their detection when using, for example, a quadrupole mass analyzer, i.e. for a quadrupole mass analyzer, the number of received signals will be less, respectively, the accuracy of determining the composition will also be lower.

Determination of the fractional composition of the hydrocarbon fluid may include determining the number of hydrocarbon fluid samples for sampling according to the established and recorded relationship between the number of hydrocarbon fluid samples for sampling, which is sufficient to determine the composition and properties of this fluid, and the permeability of the hydrocarbon reservoir formation, sampling of hydrocarbon fluid from the well , which uncovered a hydrocarbon deposit, determination of the content of hydrocarbon fractions in each sample, determination of average values of the content of hydrocarbon fractions in a hydrocarbon fluid. Determination of the number of samples depending on the formation permeability improves the accuracy of determining the range of values and, accordingly, the average values of the content of hydrocarbon fractions. A more accurate determination of the content of fractions will make it possible to determine the composition of the fluid by the method, according to the claimed method, which will ensure the achievement of the technical result.

Determination of the fractional composition of the hydrocarbon fluid may also include determining the density of the hydrocarbon fluid, determining the values of the content of hydrocarbon fractions according to the relationship between the densities and the fractional composition of the hydrocarbon fluid established and recorded in the database. Density determination in this case may include determining the number of hydrocarbon fluid samples for sampling according to the established and recorded in the database relationship between the number of hydrocarbon fluid samples for sampling, sufficient to determine the composition and properties of this fluid, and the permeability of the hydrocarbon reservoir formation, sampling of hydrocarbon fluid from the well, that opened the hydrocarbon deposit, determination of the density of the hydrocarbon fluid of each sample, determination of the average density of the hydrocarbon fluid.

The database of the relationship between the permeability of the reservoir of hydrocarbon deposits and the number of samples of hydrocarbon fluid can be formed using the following stages: sampling of hydrocarbon fluid is carried out from one of the reservoirs with a known permeability coefficient; conduct research on the composition of the selected fluid samples under the same conditions; determine the range of values of the parameters of the composition of the hydrocarbon fluid; determine the number of samples of hydrocarbon fluid, in which the range of values of the parameters of the composition of the hydrocarbon fluid does not change; all the above steps are repeated for formations with different values of the permeability coefficient; establish and record the relationship between the number of hydrocarbon fluid samples, in which the range of values of the parameters of the hydrocarbon fluid composition does not change, for each value of the reservoir permeability coefficient.

The lower the permeability of an oil and gas bearing formation, the more difficult it is to move the fluid within the formation, therefore the miscibility of the hydrocarbon fluid is difficult and, accordingly, the greater the differences in the composition of hydrocarbon fluid samples when sampling from different parts of the oil and gas bearing formation. An increase in the number of samples in this case allows for a more accurate determination of the range of values of the parameters of the composition and properties of the hydrocarbon fluid. With a low permeability coefficient (for example, below 0.05 μm ² ) of an oil and gas reservoir, it is necessary to increase the number of samples taken to improve the accuracy of determining the composition of the hydrocarbon fluid of the reservoir and to reliably determine the fingerprint of the reservoir.

The database of the relationship between the densities and the fractional composition of the hydrocarbon fluid can be formed during the implementation of the following stages: sampling of the hydrocarbon fluid is carried out from several productive formations; determine and record the density of hydrocarbon fluids of the selected samples; distillation of samples of hydrocarbon fluid at atmospheric pressure; determine the volumes of condensates of hydrocarbon fractions obtained as a result of distillation of each sample; the fractional composition of the hydrocarbon fluid of each sample is recorded; establish and fix the relationship of densities and fractional composition of hydrocarbon fluids.

Determining the density and fractional composition of the hydrocarbon fluid may further include centrifuging the hydrocarbon fluid samples at an elevated temperature and separating the hydrocarbon fluid samples from the solid sediment and / or water.

Determining the content of hydrocarbon fractions in each sample may include distilling the hydrocarbon fluid samples at atmospheric pressure and determining the volumes of condensates of hydrocarbon fractions obtained as a result of the distillation.

By separating different hydrocarbon fractions in this way, each fraction can be analyzed separately using a gas chromatography technique combined with a dedicated detector for each fraction. Combining the obtained data will also allow determining the composition of the hydrocarbon fluid with high accuracy.

The density of the hydrocarbon fluid can be determined with a vibrating density meter.

The length of the chromatographic column during gas chromatography can be from 60 to 90 meters, the heating rate of the column oven is from 1.5 ° C per minute to 5 ° C per minute. This is due to the fact that an increase in the column length provides a greater resolving power of the gas chromatography method due to a longer residence of the hydrocarbon fluid vapors in the column, respectively, a better separation of the fluid into individual components that can be identified in the hydrocarbon fluid sample and constitute its fingerprint. Increasing the column length over 90 meters does not significantly increase the resolution of the gas chromatography method. The specified heating rate allows for better separation of the hydrocarbon fluid into individual components.

When conducting gas chromatography, the result is usually a chromatogram that characterizes the composition of the hydrocarbon fluid. The method may additionally include obtaining a fingerprint of the hydrocarbon fluid based on the values of the relative heights of the alkane peaks of the obtained chromatogram characterizing its composition. Those. The formation of a set of characteristic compounds used to compose a fingerprint of a fluid can be performed by processing the chromatographic data by any known method (in particular, by the method of main components), which can then be used to compare with fingerprints of other hydrocarbon fluids and to determine the fingerprint of a specific hydrocarbon fluid in a mixture.

The technical result is also achieved when using a system for selecting a method for determining the composition of a hydrocarbon fluid, which includes a block for inputting values of the density of a hydrocarbon fluid connected to a block for selecting a gas chromatography method to determine the composition of a hydrocarbon fluid based on the density of a fluid, which is configured to determine a gas chromatography method depending on fluid density, in this case, a gas chromatography method combined with a time-of-flight mass analyzer is selected, in the case of a hydrocarbon fluid density of 0.85 g / ml or less, a gas chromatography method combined with a flame ionization detector or with a quadrupole mass analyzer , in the case of values of the density of the hydrocarbon fluid above 0.85 g / ml, but not more than 0.96 g / ml, while the gas chromatography method selection unit is connected to the data output unit on the selected method for determining the hydrocarbon fluid composition.

The technical result is also when using a system for selecting a method for determining the composition of a hydrocarbon fluid, including a block for inputting data on the fractional composition of a hydrocarbon fluid, connected to a block for selecting a gas chromatography method to determine the composition of a hydrocarbon fluid based on the fractional composition of a fluid, which is configured to determine the method of gas chromatography depending on on the fractional composition of the fluid, while choosing the method of gas chromatography, combined with a time-of-flight mass analyzer, in the case of the content of light fractions of hydrocarbons of 40% or more, the method of gas chromatography, combined with a flame ionization detector or with a quadrupole mass analyzer, in if the content of light fractions of hydrocarbon fluid is less than 40%, while the block for selecting the gas chromatography method is connected to the block for outputting data on the selected method for determining the composition of the hydrocarbon fluid.

The technical result is achieved by choosing the method of gas chromatography, combined with an ionized particle detector, which will provide a larger number of signals at the detector and, accordingly, increase the accuracy of determining the composition of the hydrocarbon fluid depending on the density of the fluid, which provides preliminary information on the fractional composition of the fluid, or from the content of light fractions of hydrocarbons. Above, the relationship between the density of a hydrocarbon fluid and its fractional composition is indicated, as well as what is the reason for the increased accuracy in determining the composition of a hydrocarbon fluid with a density of 0.85 g / ml or less and a content of light hydrocarbon fractions of 40% or more by gas chromatography combined with time a flyby mass analyzer with a density from 0.85 g / ml to 0.96 g / ml and a content of light hydrocarbon fractions less than 40% - by gas chromatography combined with a FID or a quadrupole mass analyzer.

The system for selecting a method for determining the composition of a hydrocarbon fluid, containing a block for selecting a gas chromatography method based on the density of a hydrocarbon fluid, may additionally include a database that records the relationship between the number of hydrocarbon fluid samples for sampling sufficient to determine the composition and properties of this fluid and the permeability of the hydrocarbon reservoir connected to a block for determining the number of hydrocarbon fluid samples for sampling, configured to determine the number of hydrocarbon fluid samples for sampling, sufficient to determine the composition and properties of this fluid, based on the density of the hydrocarbon fluid, while the unit determines the number of hydrocarbon fluid samples for sampling by established and recorded in the database of the relationship between the number of hydrocarbon fluid samples for sampling, sufficient to determine the properties of this fluid, and the permeability of the formation of the hydrocarbon accumulation, connected to the block for entering the density of the hydrocarbon fluid.

A system for selecting a method for determining the composition of a hydrocarbon fluid, containing a block for selecting a gas chromatography method based on the fractional composition of a hydrocarbon fluid, may additionally include a database in which the relationship between the number of hydrocarbon fluid samples for sampling sufficient to determine the properties of this fluid and the permeability of the hydrocarbon reservoir is recorded connected to a block for determining the number of hydrocarbon fluid samples for sampling, configured to determine the number of hydrocarbon fluid samples for sampling, sufficient to determine the composition and properties of this fluid, based on the fractional composition of the hydrocarbon fluid, while determining the number of hydrocarbon fluid samples for sampling according to the established and recorded in the database the relationship between the number of hydrocarbon fluid samples for sampling, sufficient to determine the properties of this fluid, and the permeability of the hydrocarbon reservoir formation connected to the block input of data on the fractional composition of the hydrocarbon fluid.

The specified database can be formed using the following stages: sampling hydrocarbon fluid from one of the reservoirs with a known permeability coefficient, determining the composition and properties of the selected fluid samples under the same conditions, determining the range of values of the parameters of the composition and properties of the hydrocarbon fluid, determining the number of hydrocarbon samples fluid, in which the range of values of the parameters of the composition and properties of the hydrocarbon fluid does not change, all the above steps are repeated for formations with different values of the permeability coefficient, the relationship between the number of hydrocarbon fluid samples is established and recorded, in which the range of values of the parameters of the composition and properties of the hydrocarbon fluid does not change, for each value of the reservoir permeability coefficient.

A system for selecting a method for determining the composition of a hydrocarbon fluid, containing a block for selecting a gas chromatography method based on the fractional composition of a hydrocarbon fluid, can additionally have a database of the relationship between densities and fractional composition of a hydrocarbon fluid, connected to a block for determining the fractional composition of a hydrocarbon fluid by its density, while the block performs determination of the fractional composition of the fluid according to the relationship between the densities and the fractional composition of the hydrocarbon fluid established and recorded in the database, connected to the data input unit for the fractional composition of the hydrocarbon fluid. In this case, the database can be formed using the following stages; sampling of hydrocarbon fluid from several productive formations is carried out, the densities of hydrocarbon fluids of the selected samples are determined and recorded, the hydrocarbon fluid samples are distilled at atmospheric pressure, the volumes of condensates of hydrocarbon fractions obtained as a result of the distillation of each samples, fix the fractional composition of the hydrocarbon fluid of each sample, establish and record the relationship between the densities and fractional composition of hydrocarbon fluids.

The block for outputting data on the composition of the hydrocarbon fluid of any of the declared systems for selecting a method for determining the composition of a hydrocarbon fluid can be additionally connected by a block for analyzing data on the composition of a hydrocarbon fluid connected to a block for outputting data on the selected method for determining the composition of a hydrocarbon fluid, while in the block for analyzing composition data In addition, a chromatogram is constructed that characterizes the composition of the hydrocarbon fluid.

In the block for analyzing data on the composition of a hydrocarbon fluid, a fingerprint of a hydrocarbon fluid can be additionally performed according to the values of the relative heights of the inter-alkane peaks of the obtained chromatogram characterizing its composition.

The invention is illustrated by the following figures.

Figure 1 shows a graph of the dependence of the content of light fractions of hydrocarbons in the composition of a hydrocarbon fluid on its density.

Figure 2 shows a graph of the dependence of the content of the diesel fraction in the composition of the hydrocarbon fluid from its density.

Figure 3 shows a chromatogram characterizing the composition of a hydrocarbon fluid with a density of 0.801 g / ml and obtained by gas chromatography combined with a time-of-flight detector.

Figure 4 shows an enlarged part of the chromatogram for hydrocarbons of the region from ₉ to C ₁₀ , characterizing the composition of a hydrocarbon fluid with a density of 0.801 g / ml and obtained by gas chromatography combined with a time-of-flight detector (obtained using specialized software).

Figure 5 shows an enlarged part of the chromatogram for hydrocarbons of the region from ₉ to C ₁₀ , characterizing the composition of the hydrocarbon fluid with a density of 0.801 g / ml and obtained by gas chromatography combined with FID (obtained using specialized software).

Figure 6 shows a chromatogram characterizing the composition of a hydrocarbon fluid with a density of 0.848 g / ml and obtained by gas chromatography combined with a time-of-flight mass analyzer.

Figure 7 shows a chromatogram characterizing the composition of a hydrocarbon fluid with a density of 0.923 g / ml and obtained by gas chromatography combined with a quadrupole mass analyzer.

Figure 8 shows graphs of the dependences of the average number of received (detected) signals when determining the composition of a hydrocarbon fluid from its density for a time-of-flight analyzer, FID and quadrupole mass analyzer.

Figure 9 shows graphs of the dependences of the average number of received (detected) signals when determining the composition of a hydrocarbon fluid on the content of light hydrocarbon fractions for a time-of-flight analyzer, FID and quadrupole mass analyzer.

Figure 10 presents a graph of estimates obtained by analyzing the relative heights of inter-alkane peaks of chromatograms of hydrocarbon fluids of different densities by the method of principal components (reflected in four separate groups of points).

Figure 11 presents a graph of estimates obtained by analyzing the relative heights of the peaks of aromatic hydrocarbons of chromatograms of hydrocarbon fluids of different densities by the method of the main components (reflected in four separate groups of points).

Figure 12 is a graph of estimates obtained by analyzing the relative peak areas of aromatic hydrocarbons of chromatograms of hydrocarbon fluids of different densities by the method of principal components (represented by four separate groups of points).

In this case, in Figures 10-12, "PC1" is the axis of the first main component, "PC2" is the axis of the second main component.

A method for determining the composition of a hydrocarbon fluid, in which the density of the hydrocarbon fluid is determined. If the density of the hydrocarbon fluid is 0.85 g / ml or less, the composition of the hydrocarbon fluid is determined by gas chromatography combined with a time-of-flight mass analyzer. If the density of the hydrocarbon fluid exceeds 0.85 g / ml to 0.96 g / ml, the composition of the hydrocarbon fluid is determined by gas chromatography combined with a flame ionization detector or a quadrupole mass analyzer.

Below are examples of implementation according to the claimed method.

Example 1. 5 samples of hydrocarbon fluid (oil) of a reservoir are taken from a productive well that has exposed one of the reservoirs of hydrocarbon deposits (reservoir permeability 0.371 μm ² ). The number of samples was determined from the previously established dependence of the number of samples required for sampling on the formation permeability values, using the database as indicated above.

Prepare hydrocarbon fluid samples and obtain hydrocarbon fluid samples. The samples are centrifuged at an elevated temperature and the aqueous phase is separated, as well as a solid precipitate, which includes mechanical impurities.

Determine the density of the hydrocarbon fluid with a vibrating densitometer. The average density for the samples was 0.806 g / ml, which is typical for ultra-light oils, which mainly include the gasoline fraction.

The obtained data are compared with the database, in which the relationship between the densities and the fractional composition of hydrocarbon fluids is recorded, examples for light and diesel fractions are shown, respectively, in Fig. 1 and 2. The database is formed as described in the description above.

As can be seen from figure 1, oils of this density are characterized by a predominance in the composition of light fractions, the content of which is about 60%, while the content of the diesel fraction, for example, is only about 23%.

Also, samples of hydrocarbon fluid samples are distilled at atmospheric pressure to obtain accurate data on the content of hydrocarbon fractions in the composition of the fluid. It was found that the composition includes 59% of light fractions of the total volume of the obtained condensate (boiling point up to 180 ° C), i.e. above 40%, 18% of kerosene fraction (boiling point from 180 ° C to 240 ° C), 23% of diesel fraction (boiling point from 240 ° C to 300 ° C).

The composition of hydrocarbon fluid samples is determined by gas chromatography combined with a time-of-flight mass analyzer. The length of the chromatographic column was 60 m, the heating rate was 1.5 ° C.

Chromatograms are obtained (an example of one of the chromatograms is shown in Fig. 3), which reflect the composition of the investigated hydrocarbon fluid. In this case, the obtained chromatograms are analyzed by the relative heights of the alkane peaks. The values of the average number of received signals, which reflect the accuracy of determining the composition, are shown in Table 1. The obtained chromatograms of all five samples of the hydrocarbon fluid are compared, and the standard deviation of the chromatogram peaks is determined. When analyzing the obtained values of the relative heights of inter-alkane peaks using the method of principal components, a fingerprint of the investigated hydrocarbon fluid is obtained.

To illustrate and confirm the achievement of the claimed technical result, the composition of the specified hydrocarbon fluid is determined by gas chromatography combined with other types of detectors (FID and quadrupole mass analyzer). Table 1 shows the obtained values of the number of received signals, as well as the mean square deviation (RMS) for the received signals.

Table 1 Detector type Number of received signals RMS Time-of-flight mass analyzer 356 5.7 Quadrupole Mass Analyzer 311 9.8 PID 326 6.5

It can be seen from the table that for a time-of-flight analyzer the number of received signals is much larger than with other types of detectors, which corresponds to the higher accuracy of this type of detector for analyzing a hydrocarbon fluid when the content of light hydrocarbon fractions in the distillate fractions is more than 40% and the fluid density is less than 0 , 85 g / ml.

When comparing Figures 4 and 5, which show enlarged parts of the chromatograms obtained for different types of detectors (time-of-flight mass analyzer and FID), a change in the shape of the chromatograms and a better separation of hydrocarbon peaks when using a time-of-flight mass analyzer are seen, which also indicates on increasing the accuracy in determining the composition of a hydrocarbon fluid with a density of 0.806 g / ml (less than 0.85 g / ml) when using the claimed method.

Example 2. 16 samples of hydrocarbon fluid (oil) are taken from a productive well that has opened one of the layers of a hydrocarbon deposit (formation permeability 0.00173 μm ² ). Prepare samples and obtain samples of hydrocarbon fluid in the same way as in example 1.

Determine the density of the hydrocarbon fluid with a vibrating densitometer. The average density was 0.848 g / ml, which is typical for light oils.

Also in this case, the fractional composition of the hydrocarbon fluid was determined. The content of light fractions was 41%, kerosene fraction - 27%, diesel fraction - 32%.

The composition of the hydrocarbon fluid is determined by gas chromatography combined with a time-of-flight mass analyzer. The length of the chromatographic column was 60 m, the heating rate was 1.5 ° C.

Chromatograms are obtained (an example chromatogram is shown in Fig. 6), which reflect the composition of the analyzed hydrocarbon fluid. In this case, the obtained chromatograms are analyzed by the relative heights of the alkane peaks. The values of the average number of received signals and the root-mean-square deviations of the values of the chromatogram peaks are given in Table 2.

When analyzing the obtained values of the relative heights of inter-alkane peaks using the principal component method, a fingerprint of the analyzed hydrocarbon fluid is obtained.

To illustrate and confirm the achievement of the claimed technical result, the composition of the specified hydrocarbon fluid is determined by gas chromatography combined with other types of detectors (FID and quadrupole mass analyzers). Table 2 shows the obtained values of the number of received signals and RMS.

table 2 Detector type Number of received signals RMS Time-of-flight mass analyzer 350 7.8 Quadrupole Mass Analyzer 329 7.5 PID 341 7,7

The table shows that the maximum number of signals was obtained when determining the composition of oil by gas chromatography, combined with a time-of-flight mass analyzer, which indicates the achievement of the technical result when implementing the claimed method. For other detectors, the number of received signals is less.

Example 3. 5 samples of hydrocarbon fluid (oil) of a reservoir are taken from a productive well that has exposed one of the reservoirs of hydrocarbon deposits (reservoir permeability 0.0209 μm ² ). Prepare samples and obtain samples of hydrocarbon fluid in the same way as in example 1.

Determine the density of the hydrocarbon fluid with a vibrating densitometer. The average density was 0.923 g / ml, which is typical for medium-density oils, which mainly include the diesel fraction. The fractional composition of the hydrocarbon fluid is also determined. For this, samples of hydrocarbon fluid are distilled at atmospheric pressure. The distribution by fractions was: 4.1% of light fractions of hydrocarbons (of the total volume of condensates obtained), 16.9% of the kerosene fraction and 79% of the diesel fraction.

The composition of the hydrocarbon fluid is determined by gas chromatography combined with a quadrupole mass analyzer. The length of the chromatographic column was 60 m, the heating rate was 1.5 ° C. Achievement of the technical result in this case is also possible when using PID.

Chromatograms are obtained (an example chromatogram is shown in Fig. 7), which reflect the composition of the analyzed hydrocarbon fluid. In this case, the obtained chromatograms are analyzed by the relative heights of the alkane peaks. The values of the average number of received signals and the root-mean-square deviations of the values of the chromatogram peaks are shown in Table 3.

When analyzing the obtained values, the relative heights of inter-alkane peaks using the method of principal components, a fingerprint of the analyzed hydrocarbon fluid is obtained.

To illustrate and confirm the achievement of the claimed technical result, the composition of the specified hydrocarbon fluid is determined by gas chromatography combined with other types of detectors (time-of-flight and FID). Table 3 shows the values of the number of received signals and RMS.

Table 3 Detector type Number of received signals RMS Time-of-flight mass analyzer 310 12.5 Quadrupole Mass Analyzer 355 5.8 PID 356 5.6

The table shows that the maximum number of signals received for the PID, which indicates the achievement of the technical result when implementing the claimed method. The number of signals obtained using a quadrupole mass analyzer is also close to the number obtained using a FID. For a time-of-flight analyzer, the number of received signals is significantly reduced, while a large increase in RMS is observed, which indicates a decrease in the accuracy of this detector for analyzing a hydrocarbon fluid when the content of light fractions of hydrocarbons is less than 40% and a fluid density of more than 0.85 g / ml.

Example 4. 8 samples of hydrocarbon fluid (oil) of a reservoir are taken from a productive well that has exposed one of the reservoirs of hydrocarbon deposits (reservoir permeability is 0.0154 μm ² ). Prepare samples and obtain samples of hydrocarbon fluid in the same way as in example 1.

The density of the hydrocarbon fluid is determined with a vibrating densitometer. The average density was 0.888 g / ml, which is typical for medium density oils.

The obtained data are compared with the data base, in which the relationship of densities and fractional composition of hydrocarbon fluids is recorded, examples for gasoline and diesel fractions are shown, respectively, in Fig. 1 and 2, indicated in example 1. As can be seen from figure 1, for oils of this density, a predominance in the composition of the diesel fraction (the content of which is about 50%) is characteristic, while the content of the gasoline fraction is about 20% (i.e. less than 40%).

The composition of the hydrocarbon fluid is determined by gas chromatography combined with a flame ionization detector. The length of the chromatographic column was 60 m, the heating rate was 1.5 ° C. Achievement of the technical result in this case is also possible when using a quadrupole mass spectrometer as a detector.

As a result, chromatograms are obtained that characterize the composition of the hydrocarbon fluid. In this case, the obtained chromatograms are analyzed by the relative heights of the alkane peaks. The values of the average number of received signals, which characterize the accuracy of the detector for a hydrocarbon fluid of the indicated density, and the root-mean-square deviations of the chromatogram peaks are shown in Table 4.

When analyzing the obtained values of the relative heights of inter-alkane peaks using the principal component method, a fingerprint of the analyzed hydrocarbon fluid is obtained.

To illustrate and confirm the achievement of the claimed technical result, the composition of the specified hydrocarbon fluid is determined by gas chromatography combined with other detectors (time-of-flight and quadrupole mass analyzers). Table 4 shows the average values of the number of signals obtained on the chromatograms and RMS.

Table 4 Detector type Number of received signals RMS Time-of-flight mass analyzer 311 7.4 Quadrupole Mass Analyzer 342 6,7 PID 358 4,3

The table shows that the maximum number of signals received for the PID, which indicates the achievement of the technical result when implementing the claimed method. The number of signals obtained using a quadrupole mass analyzer is also close to the number obtained for the FID. For a time-of-flight analyzer, the number of received signals is significantly reduced, which indicates a decrease in the accuracy of determining the composition of a hydrocarbon fluid containing light hydrocarbon fractions less than 40% and with a density of more than 0.85 g / ml using a time-of-flight mass analyzer.

The composition of hydrocarbon fluids of different densities was determined in a similar way. Table 5 shows the average values of the number of received signals when determining the composition of hydrocarbon fluids of different densities and different contents of light hydrocarbon fractions by gas chromatography, combined with either a time-of-flight mass analyzer, or a quadrupole mass analyzer, or an FID.

Table 5 Density, g / ml Content of light fractions of hydrocarbons,% Average values of the number of signals obtained on a time-of-flight mass analyzer Average values of the number of signals obtained on a quadrupole mass analyzer Average values of the number of signals obtained on the flame ionization detector 0.806 59 358 311 325 0.821 54 362 317 330 0.832 47.5 355 315 338 0.848 41 350 326 341 0.858 36 337 329 343 0.871 29 320 338 355 0.888 17 311 342 358 0.910 15.3 307 349 354 0.923 4.1 310 355 356

Figures 8 and 9 show graphs of changes in the average value of the number of received signals for three detectors of ionized particles with changes in the density of the hydrocarbon fluid, the composition of which was determined, and the content of light fractions of hydrocarbons. As can be seen from figure 8, with an increase in the density of a hydrocarbon fluid, a sharp decrease in the number of signals is observed with an increase in density of more than 0.85 g / ml for a time-of-flight mass analyzer, while for a FID and a quadrupole mass analyzer, the number of signals increases with increasing density and at a density greater than 0.85 g / ml exceeds the number of signals obtained for the time-of-flight mass analyzer. This confirms the achievement of the technical result when implementing the claimed invention.

A similar dependence is observed in the graphs presented in Figure 9. With a decrease in the content of light fractions of hydrocarbons in the composition of a hydrocarbon fluid from 40% or more, a sharp increase in the number of signals is observed when determining the composition of the fluid by gas chromatography, combined with a time-of-flight mass analyzer, which provides improving the accuracy of determining the composition of the fluid. In this case, for the method of gas chromatography, combined with a quadrupole mass analyzer or with a flame ionization detector, an increase in the number of received signals (an increase in the accuracy of determining the composition) is observed when the content of light fractions of hydrocarbons is less than 40%.

The presented data show that for a time-of-flight mass analyzer, high accuracy is not characteristic of the entire mass range, while with an increase in the mass of hydrocarbons included in the hydrocarbon fluid, the accuracy of determining the composition, on the contrary, decreases. At the same time, for a quadrupole mass analyzer, with an increase in the range of masses that are part of a hydrocarbon fluid, an increase in the accuracy of determining the composition of the fluid is observed.

Determination of a gas chromatography method combined with a time-of-flight mass analyzer or a quadrupole mass analyzer or FID can also be carried out using a system for selecting a method for determining the composition of a hydrocarbon fluid. This happens when you enter data on either the density of the hydrocarbon fluid or the content of light fractions in the fluid (the fractional composition of the hydrocarbon fluid).

Figure 10 presents a graph obtained by analyzing the values of the relative heights of alkane peaks by the method of principal components for all hydrocarbon fluids from examples 1 to 4 (reflected by four separate groups of points). Comparison of the ranges of values for the given hydrocarbon fluids shows that the degree of intersection of the regions is 30%. In this case, the intersection of the ranges of values for these fluids, obtained when analyzing the values of the relative heights of peaks of sterane hydrocarbons by the method of main components, is, for example, 60%, alkane - 63%, aromatic - 47% (Figure 11). At the same time, the analysis of the values of the relative peak area, for example, aromatic hydrocarbons, shows the intersection of the ranges of values by 64% (figure 12). The data obtained confirm that the use of the claimed method allows for a higher accuracy in determining the composition and a decrease in the intersection of the ranges of values of fingerprints of hydrocarbon fluids.

Thus, the above examples confirm that the claimed methods for determining the composition of the fluid, as well as the system for selecting the method for determining the composition of the fluid, allow for an increase in the accuracy of determining the composition and obtaining a fingerprint of the hydrocarbon fluid, which provides an increase in the distinguishability of hydrocarbon fluids relative to each other. The achievement of the technical result is ensured by preliminary determination of the density of the hydrocarbon fluid or the content of light fractions of hydrocarbons in the composition of the fluid.

Claims (108)

1. A method for determining the composition of a hydrocarbon fluid, including: determination of the density of the hydrocarbon fluid, determination of hydrocarbon fluid composition by gas chromatography method: - combined with a time-of-flight mass analyzer in the case of a hydrocarbon fluid density of 0.85 g / ml or less; - combined with a flame ionization detector or with a quadrupole mass analyzer in the case of values of the density of the hydrocarbon fluid above 0.85 g / ml, but not more than 0.96 g / ml. 2. The method for determining the composition of a hydrocarbon fluid according to claim 1, wherein determining the density of the hydrocarbon fluid comprises: - determination of the number of hydrocarbon fluid samples for sampling according to the established and recorded in the database the relationship between the number of hydrocarbon fluid samples for sampling and the permeability of the hydrocarbon reservoir formation; - sampling of hydrocarbon fluid from a well that has exposed a hydrocarbon deposit; - determination of the density of the hydrocarbon fluid of each sample; - determination of the average density of the hydrocarbon fluid. 3. A method for determining the composition of a hydrocarbon fluid according to claim 2, in which the database is formed using the following steps: - take samples of hydrocarbon fluid from one of the reservoirs with a known permeability coefficient; - determine the composition and properties of the selected fluid samples under the same conditions; - determine the range of values of the parameters of the composition and properties of the hydrocarbon fluid; - determine the number of samples of hydrocarbon fluid, in which the range of values of the parameters of the composition and properties of the hydrocarbon fluid does not change; - all the above steps are repeated for formations with different values of the permeability coefficient; - establish and fix the relationship of the number of hydrocarbon fluid samples, in which the range of values of the parameters of the composition and properties of the hydrocarbon fluid does not change, for each value of the reservoir permeability coefficient. 4. A method for determining the composition of a hydrocarbon fluid according to claim 2, which further comprises centrifuging the hydrocarbon fluid samples at an elevated temperature and separating the hydrocarbon fluid samples from the solid sediment and / or water before determining the density of the hydrocarbon fluid. 5. The method for determining the composition of a hydrocarbon fluid according to claim 2, which further comprises centrifuging the hydrocarbon fluid samples at an elevated temperature and separating the hydrocarbon fluid of the samples from the solid sediment and / or water before determining the density of the hydrocarbon fluid. 6. The method for determining the composition of a hydrocarbon fluid according to claim 2, wherein the determination of the density of the hydrocarbon fluid is carried out by a vibrating densitometer. 7. A method for determining the composition of a hydrocarbon fluid according to claim 1, wherein during gas chromatography the length of the chromatographic column is 60 to 90 meters, the heating rate of the column thermostat is from 1.5 ° C per minute to 5 ° C per minute. 8. A method for determining the composition of a hydrocarbon fluid according to claim 1, wherein determining the composition of a hydrocarbon fluid includes obtaining a chromatogram characterizing its composition. 9. The method for determining the composition of a hydrocarbon fluid according to claim 8, which further comprises obtaining a fingerprint of the hydrocarbon fluid from the values of the relative heights of the alkane peaks of the obtained chromatogram characterizing its composition. 10. A method for determining the composition of a hydrocarbon fluid, including: determination of the fractional composition of the hydrocarbon fluid, determination of hydrocarbon fluid composition by gas chromatography method: - combined with a time-of-flight mass analyzer in the case of 40% or more of light hydrocarbon fractions in the hydrocarbon fluid; - combined with a flame ionization detector or with a quadrupole mass analyzer if the content of light hydrocarbon fractions in the hydrocarbon fluid is less than 40%. 11. A method for determining the composition of a hydrocarbon fluid according to claim 10, wherein determining the fractional composition of a hydrocarbon fluid comprises: - determination of the number of hydrocarbon fluid samples for sampling according to the established and recorded in the database the relationship between the number of hydrocarbon fluid samples for sampling and the permeability of the hydrocarbon reservoir formation; - sampling of hydrocarbon fluid from a well that has exposed a hydrocarbon deposit; - determination of the content of hydrocarbon fractions in each sample; - determination of the average values of the content of hydrocarbon fractions in the hydrocarbon fluid. 12. The method for determining the composition of a hydrocarbon fluid according to claim 11, in which the database is generated using the following steps: - take samples of hydrocarbon fluid from one of the reservoirs with a known permeability coefficient; - determine the composition and properties of the selected fluid samples under the same conditions; - determine the range of values of the parameters of the composition and properties of the hydrocarbon fluid; - determine the number of samples of hydrocarbon fluid, in which the range of values of the parameters of the composition and properties of the hydrocarbon fluid does not change; - all the above steps are repeated for formations with different values of the permeability coefficient; - establish and fix the relationship of the number of hydrocarbon fluid samples, in which the range of values of the parameters of the composition and properties of the hydrocarbon fluid does not change, for each value of the reservoir permeability coefficient. 13. A method for determining the composition of a hydrocarbon fluid according to claim 10, wherein determining the fractional composition of a hydrocarbon fluid comprises: - determination of the density of the hydrocarbon fluid; - determination of the values of the content of hydrocarbon fractions according to the relationship between the densities and the fractional composition of the hydrocarbon fluid established and recorded in the database. 14. The method for determining the composition of a hydrocarbon fluid according to claim 13, wherein determining the density of the hydrocarbon fluid comprises: - determination of the number of hydrocarbon fluid samples for sampling according to the established and recorded in the database the relationship between the number of hydrocarbon fluid samples for sampling and the permeability of the hydrocarbon reservoir formation; - sampling of hydrocarbon fluid from a well that has exposed a hydrocarbon deposit; - determination of the density of the hydrocarbon fluid of each sample; - determination of the average density of the hydrocarbon fluid. 15. The method for determining the composition of a hydrocarbon fluid according to claim 14, in which the database is generated using the following steps: - take samples of hydrocarbon fluid from one of the reservoirs with a known permeability coefficient; - carry out studies of the composition of the selected fluid samples under the same conditions; - determine the range of values of the parameters of the composition and properties of the hydrocarbon fluid; - determine the number of samples of hydrocarbon fluid, in which the range of values of the parameters of the composition and properties of the hydrocarbon fluid does not change; - all the above steps are repeated for formations with different values of the permeability coefficient; - establish and record the relationship of the number of hydrocarbon fluid samples, in which the range of values of the parameters of the hydrocarbon fluid composition does not change, for each value of the reservoir permeability coefficient. 16. The method for determining the composition of a hydrocarbon fluid according to claim 13, in which the database is generated using the following steps: - carry out sampling of hydrocarbon fluid from productive formations; - determine and record the density of hydrocarbon fluids of the selected samples; - carry out the distillation of samples of hydrocarbon fluid at atmospheric pressure; - determine the volumes of condensates of hydrocarbon fractions obtained as a result of distillation of each sample; - fix the fractional composition of the hydrocarbon fluid of each sample; - establish and record the relationship of densities and fractional composition of hydrocarbon fluids. 17. The method for determining the composition of a hydrocarbon fluid according to claim 13, further comprising centrifuging the hydrocarbon fluid samples at an elevated temperature and separating the hydrocarbon fluid samples from the solid sediment and / or water prior to determining the density of the hydrocarbon fluid. 18. The method for determining the composition of a hydrocarbon fluid according to claim 11, which further comprises centrifuging the hydrocarbon fluid samples at an elevated temperature and separating the hydrocarbon fluid of the samples from the solid sediment and / or water before determining the content of hydrocarbon fractions. 19. The method for determining the composition of a hydrocarbon fluid according to claim 11, in which determining the content of hydrocarbon fractions in each sample includes: - distillation of samples of hydrocarbon fluid at atmospheric pressure; - determination of volumes of condensates of hydrocarbon fractions obtained as a result of distillation. 20. A method for determining the composition of a hydrocarbon fluid according to claim 10, in which light hydrocarbon fractions correspond to hydrocarbon fractions boiling away at temperatures up to 180 ° C. 21. The method for determining the composition of a hydrocarbon fluid according to claim 13, wherein the determination of the density of the hydrocarbon fluid is carried out with a vibrating density meter. 22. The method for determining the composition of a hydrocarbon fluid according to 10, in which, when carrying out gas chromatography, the length of the chromatographic column is from 60 to 90 meters, the heating rate of the column thermostat is from 1.5 ° C per minute to 5 ° C per minute. 23. The method for determining the composition of a hydrocarbon fluid according to claim 10, wherein determining the composition of the hydrocarbon fluid includes obtaining a chromatogram characterizing its composition. 24. The method for determining the composition of a hydrocarbon fluid according to claim 23, which further comprises obtaining a fingerprint of the hydrocarbon fluid from the values of the relative heights of the alkane peaks of the obtained chromatogram characterizing its composition. 25. A system for selecting a method for determining the composition of a hydrocarbon fluid, including a block for entering values of the density of a hydrocarbon fluid connected to a block for selecting a gas chromatography method to determine the composition of a hydrocarbon fluid based on the density of a fluid, which is configured to determine a gas chromatography method depending on the density of a fluid, when this chooses: - the method of gas chromatography, combined with a time-of-flight mass analyzer, in the case of values of the density of the hydrocarbon fluid 0.85 g / ml or less; - the method of gas chromatography, combined with a flame ionization detector or with a quadrupole mass analyzer, in the case of values of the density of the hydrocarbon fluid over 0.85 g / ml, but not more than 0.96 g / ml; the block for selecting the gas chromatography method is connected to the block for outputting data on the selected method for determining the composition of the hydrocarbon fluid. 26. The system for selecting a method for determining the composition of a hydrocarbon fluid according to claim 25, additionally including a database in which the relationship between the number of hydrocarbon fluid samples for sampling and the permeability of a hydrocarbon reservoir formation is recorded, connected to a block for determining the number of hydrocarbon fluid samples for sampling, configured to determine the number of hydrocarbon fluid samples for sampling based on the density of the hydrocarbon fluid, while the block determines the number of hydrocarbon fluid samples for sampling according to the established and recorded relationship between the number of hydrocarbon fluid samples for sampling and the permeability of the hydrocarbon reservoir, connected to the block for entering the hydrocarbon density values fluid. 27. The system for selecting a method for determining the composition of a hydrocarbon fluid according to claim 26, in which the database is formed using the following stages: - take samples of hydrocarbon fluid from one of the reservoirs with a known permeability coefficient; - determine the composition and properties of the selected fluid samples under the same conditions; - determine the range of values of the parameters of the composition and properties of the hydrocarbon fluid; - determine the number of samples of hydrocarbon fluid, in which the range of values of the parameters of the composition and properties of the hydrocarbon fluid does not change; - all the above steps are repeated for formations with different values of the permeability coefficient; - establish and fix the relationship of the number of hydrocarbon fluid samples, in which the range of values of the parameters of the composition and properties of the hydrocarbon fluid does not change, for each value of the reservoir permeability coefficient. 28. The system for selecting a method for determining the composition of a hydrocarbon fluid according to claim 25, in which the block for outputting data on the composition of a hydrocarbon fluid is additionally connected to a block for analyzing data on the composition of a hydrocarbon fluid connected to a block for outputting data on the selected method for determining the composition of a hydrocarbon fluid, while in the block for analyzing data on the composition of the hydrocarbon fluid is additionally constructed a chromatogram characterizing the composition of the hydrocarbon fluid. 29. The system for selecting a method for determining the composition of a hydrocarbon fluid according to claim 28, in which a fingerprint of a hydrocarbon fluid is additionally obtained in the block for analyzing data on the composition of a hydrocarbon fluid according to the values of the relative heights of the inter-alkane peaks of the obtained chromatogram characterizing its composition. 30. A system for selecting a method for determining the composition of a hydrocarbon fluid, including a data input unit for the fractional composition of a hydrocarbon fluid, connected to a unit for selecting a gas chromatography method to determine the composition of a hydrocarbon fluid based on the fractional composition of a fluid, which is configured to determine a gas chromatography method depending on the fractional composition fluid, while choosing: - the method of gas chromatography, combined with a time-of-flight mass analyzer, in the case of the content of light fractions of hydrocarbons of 40% or more; - the method of gas chromatography, combined with a flame ionization detector or with a quadrupole mass analyzer, if the content of light fractions of a hydrocarbon fluid is less than 40%; the block for selecting the gas chromatography method is connected to the block for outputting data on the selected method for determining the composition of the hydrocarbon fluid. 31. The system for selecting a method for determining the composition of a hydrocarbon fluid according to claim 30, additionally including a database in which the relationship between the number of hydrocarbon fluid samples for sampling and the permeability of a hydrocarbon reservoir formation is recorded, connected to a unit for determining the number of hydrocarbon fluid samples for sampling, configured to determine the number of hydrocarbon fluid samples for sampling based on the fractional composition of the hydrocarbon fluid, while the block determines the number of hydrocarbon fluid samples for sampling based on the relationship between the number of hydrocarbon fluid samples for sampling and the permeability of the hydrocarbon reservoir, which is connected to the fractional composition of the hydrocarbon fluid. 32. The system for selecting a method for determining the composition of a hydrocarbon fluid according to claim 31, in which the database is formed using the following stages: - take samples of hydrocarbon fluid from one of the reservoirs with a known permeability coefficient; - determine the composition and properties of the selected fluid samples under the same conditions; - determine the range of values of the parameters of the composition and properties of the hydrocarbon fluid; - determine the number of samples of hydrocarbon fluid, in which the range of values of the parameters of the composition and properties of the hydrocarbon fluid does not change; - all the above steps are repeated for formations with different values of the permeability coefficient; - establish and fix the relationship of the number of hydrocarbon fluid samples, in which the range of values of the parameters of the composition and properties of the hydrocarbon fluid does not change, for each value of the reservoir permeability coefficient. 33. A system for selecting a method for determining the composition of a hydrocarbon fluid according to claim 30, additionally including a database of the relationship between densities and fractional composition of a hydrocarbon fluid, connected to a block for determining the fractional composition of a hydrocarbon fluid by its density, while the block is used to determine the fractional composition of the fluid according to the established and fixed in the database of the relationship between the densities and the fractional composition of the hydrocarbon fluid, connected to the data input unit for the fractional composition of the hydrocarbon fluid. 34. The system for selecting a method for determining the composition of a hydrocarbon fluid according to claim 33, in which the database is formed using the following stages: - sampling of hydrocarbon fluid is carried out from several productive formations; - determine and record the density of hydrocarbon fluids of the selected samples; - carry out the distillation of samples of hydrocarbon fluid at atmospheric pressure; - determine the volumes of condensates of hydrocarbon fractions obtained as a result of distillation of each sample; - fix the fractional composition of the hydrocarbon fluid of each sample; - establish and record the relationship of densities and fractional composition of hydrocarbon fluids. 35. A system for selecting a method for determining the composition of a hydrocarbon fluid according to claim 30, in which the block for outputting data on the composition of a hydrocarbon fluid is additionally connected to a block for analyzing data on the composition of a hydrocarbon fluid connected to a block for outputting data on the selected method for determining the composition of a hydrocarbon fluid, while in the block for analyzing data on the composition of the hydrocarbon fluid is additionally constructed a chromatogram characterizing the composition of the hydrocarbon fluid. 36. The system for selecting a method for determining the composition of a hydrocarbon fluid according to claim 35, in which a fingerprint of a hydrocarbon fluid is additionally obtained in the block for analyzing data on the composition of a hydrocarbon fluid according to the values of the relative heights of inter-alkane peaks of the obtained chromatogram characterizing its composition.

Images