Reservoir stratum type identification method and system based on thermal evaporation hydrocarbon

Abstract

The invention discloses a reservoir stratum type identification method and system based on thermal evaporation hydrocarbon, and the method comprises the steps: heating a rock sample from a to-be-identified reservoir stratum, and collecting a hydrocarbon mixture generated in the heating process; separating the hydrocarbon mixture into a plurality of monomer hydrocarbons, and then identifying n-alkanes in the monomer hydrocarbons; the method comprises the following steps: acquiring a chromatographic peak of each monomer hydrocarbon, then integrating all the chromatographic peaks into a total structure peak representing the content of a hydrocarbon mixture in a to-be-identified reservoir oil-gas component, and integrating n-alkane chromatographic peaks with a specified carbon number range into a first chromatographic peak representing the content of n-alkane, so as to identify the content of the n-alkane in the to-be-identified reservoir oil-gas component, and on the basis, determining the content of the n-alkane in the to-be-identified reservoir oil-gas component. Obtaining a second chromatographic peak representing the content of the unrecognizable substance; and determining the type of the reservoir stratum according to the percentage of the second chromatographic peak area in the total structure peak area and the ratio of the second chromatographic peak area to the first chromatographic peak area. According to the invention, the oil-water identification precision is effectively improved, and the rapid and accurate identification of the type of the reservoir stratum is realized.

Description

Technical Field

[0001] The present invention belongs to the field of reservoir type identification, and particularly relates to a method and system for identifying reservoir types based on thermally evaporated hydrocarbons. Background Art

[0002] Currently, how to quickly and accurately determine the properties of reservoir fluids and effectively improve the coincidence rate of comprehensive mud logging interpretation, especially to determine whether the reservoir contains water, has always been a difficult problem in mud logging. Therefore, there is an urgent need for various new methods and means to solve the current problems.

[0003] The gas chromatography analysis technology of thermally evaporated hydrocarbons is a technology widely used in the field of petroleum geology. In previous research, the characteristics of the reservoir were mainly determined by analyzing parameters such as the peak shape, carbon number range, main peak carbon, and longitudinal changes of the reservoir of n-alkanes, and the application of the carbon number distribution characteristics of the unidentifiable substances accompanying them has not been carried out. In this technology, the complex hydrocarbon mixture generated by rock pyrolysis is separated into monomeric hydrocarbons, and then, based on the changes of monomeric n-alkanes, the crude oil properties and oil-bearing characteristics of the reservoir are evaluated, so as to quickly distinguish the fluid properties. All along, this technology has not involved the application of data on unidentifiable substances other than n-alkanes. The main reasons are as follows: (1) There are certain difficulties in naming and reading the values of unidentifiable substances that appear irregularly; (2) There are no available research results on the role of unidentifiable substances.

[0004] In the process of implementing the present invention, based on continuous observation and experiments, the inventor found that there is a certain correlation between the unidentifiable substances and the water content in the oil layer. Considering the total hydrocarbon content in the thermally evaporated hydrocarbons as the basis for determining the crude oil content in the reservoir can obtain more realistic reservoir crude oil characteristics. Therefore, there is an urgent need for a method to obtain reservoir crude oil characteristics based on all thermally evaporated hydrocarbons. Summary of the Invention

[0005] To solve the above problems, an embodiment of the present invention provides a method for identifying reservoir types based on thermally evaporated hydrocarbons, including: heating a rock sample taken from a reservoir to be identified, and collecting the hydrocarbon mixture generated during the heating process; separating the hydrocarbon mixture into multiple monomeric hydrocarbons, and then identifying the n-alkanes therein; obtaining the chromatographic peak of each monomeric hydrocarbon, and then integrating all the chromatographic peaks into a total peak representing the content of the hydrocarbon mixture in the oil and gas components of the reservoir to be identified, and integrating the chromatographic peaks of n-alkanes with a specified carbon number range into a first chromatographic peak representing the content of n-alkanes. Based on this, a second chromatographic peak representing the content of unidentifiable substances is obtained; the type of the reservoir is determined according to the percentage of the area of the second chromatographic peak in the area of the total peak and the ratio between the area of the second chromatographic peak and the area of the first chromatographic peak.

[0006] Preferably, the remaining monomeric hydrocarbons that are not identified as normal alkanes are regarded as unidentified substances, and the unidentified substances include, but are not limited to, isoparaffins, naphthenes, and aromatic hydrocarbons.

[0007] Preferably, capillary column chromatography technology is used to analyze the composition of the hydrocarbon mixture, so as to separate the hydrocarbon mixture into multiple monomeric hydrocarbons.

[0008] Preferably, the specified carbon number range is C12 - C40.

[0009] Preferably, in the process of determining the reservoir type, it includes: if the percentage of the second chromatographic peak area in the total peak area satisfies the first ratio range, and the ratio between the second chromatographic peak area and the first chromatographic peak area satisfies the second ratio range, then it is determined that the reservoir type is an oil layer, where the first ratio range is 5% - 40%, and the second ratio range is 0.06 - 0.67; if the percentage of the second chromatographic peak area in the total peak area satisfies the third ratio range, and the ratio between the second chromatographic peak area and the first chromatographic peak area satisfies the fourth ratio range, then it is determined that the reservoir type is an oil-bearing water layer, where the third ratio range is 50% - 95%, and the fourth ratio range is 0.93 - 18.45.

[0010] Preferably, after determining the reservoir type, the reservoir type identification method further includes: collecting the percentage data of the second chromatographic peak area in the total peak area corresponding to multiple identified different types of reservoirs, and analyzing the actual oil content and actual water content of each reservoir based on the corresponding second chromatographic peak area to obtain the first correlation relationship between the percentage data of the second chromatographic peak area and the oil content or water content, where the percentage data of the second chromatographic peak area is inversely proportional to the oil content and directly proportional to the water content.

[0011] Preferably, the reservoir type identification method further includes: according to the first correlation relationship, obtaining the second correlation relationship between the content of unidentified substances and the oil content or water content, where the content of unidentified substances is inversely proportional to the oil content and directly proportional to the water content.

[0012] Preferably, in the step of heating the rock sample taken from the reservoir to be identified and collecting the hydrocarbon mixture generated during the heating process, it includes: placing the rock sample into a pyrolysis furnace for heating, and starting to collect the hydrocarbon mixture when the temperature in the pyrolysis furnace reaches a constant temperature of 300°C.

[0013] On the other hand, the present invention also provides a reservoir type identification system based on thermally evaporated hydrocarbons, characterized in that the reservoir type identification system comprises the following modules: a product collection module for heating a rock sample taken from a reservoir to be identified and collecting the hydrocarbon mixture generated during the heating process; a hydrocarbon type identification module for separating the hydrocarbon mixture into a plurality of individual hydrocarbons and then identifying the n-alkanes therein; a chromatographic peak acquisition module for acquiring the chromatographic peaks of each individual hydrocarbon and then integrating all the chromatographic peaks into a total chromatographic peak characterizing the content of the hydrocarbon mixture in the oil and gas components of the reservoir to be identified, and integrating the chromatographic peaks of the n-alkanes within a specified carbon number range into a first chromatographic peak characterizing the content of the n-alkanes, and based on this, obtaining a second chromatographic peak characterizing the content of the unidentifiable substances; a reservoir type determination module for determining the reservoir type according to the percentage of the area of the second chromatographic peak in the area of the total chromatographic peak and the ratio between the area of the second chromatographic peak and the area of the first chromatographic peak.

[0014] Preferably, the reservoir type identification system further comprises: a data processing module for, after determining the reservoir type, collecting the percentage data of the area of the second chromatographic peak in the area of the total chromatographic peak corresponding to a plurality of identified different types of reservoirs, and analyzing the actual oil content and actual water content of each reservoir according to the corresponding area of the second chromatographic peak to obtain a first correlation relationship between the percentage data of the area of the second chromatographic peak and the oil content or water content, wherein the percentage data of the area of the second chromatographic peak is inversely proportional to the oil content and directly proportional to the water content.

[0015] Compared with the prior art, one or more embodiments of the above solutions may have the following advantages or beneficial effects:

[0016] The present invention proposes a method and system for identifying reservoir types based on thermally evaporated hydrocarbons. The method first obtains the hydrocarbon mixture contained in a rock sample taken from a reservoir to be identified, and separately identifies the n-alkanes and the unidentifiable substances other than the identified n-alkanes in the hydrocarbon mixture; then, separately obtains the total chromatographic peak of the hydrocarbon mixture, the first chromatographic peak of the n-alkanes, and the second chromatographic peak of the unidentifiable substances; finally, determines the reservoir type according to the percentage of the area of the second chromatographic peak in the area of the total chromatographic peak and the ratio between the area of the second chromatographic peak and the area of the first chromatographic peak. The present invention effectively improves the accuracy of oil-water identification and realizes the rapid and accurate identification of reservoir types. At the same time, the present invention enriches the judgment means for comprehensively interpreting oil, gas and water layers in logging, can be widely applied to the judgment link of reservoir water flooding status in the field of oil and gas exploration and development, assists in comprehensive interpretation and evaluation, and as a scientific and efficient oil-water identification means, effectively improves the logging interpretation accuracy.

[0017] Other features and advantages of the present invention will be set forth in the following description, and in part will be obvious from the description, or may be learned by practice of the present invention. The objectives and other advantages of the present invention can be realized and attained by the structure particularly pointed out in the specification, claims, and drawings. Brief Description of the Drawings

[0018] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. They are used in conjunction with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the drawings:

[0019] Figure 1 It is a step diagram of the method for identifying reservoir types based on thermally evaporated hydrocarbons according to an embodiment of the present application.

[0020] Figure 2 It is a block diagram of the modules of the system for identifying reservoir types based on thermally evaporated hydrocarbons according to an embodiment of the present application. Detailed Embodiments

[0021] The following will describe in detail the embodiments of the present invention in conjunction with the drawings and embodiments, so as to fully understand how the present invention uses technical means to solve technical problems and achieve the realization process of technical effects and implement accordingly. It should be noted that as long as there is no conflict, the various embodiments in the present invention and the various features in each embodiment can be combined with each other, and the formed technical solutions are all within the protection scope of the present invention.

[0022] In addition, the steps shown in the flowchart of the drawings can be executed in a computer system such as a set of computer-executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0023] Currently, how to quickly and accurately determine the properties of reservoir fluids and effectively improve the coincidence rate of comprehensive mud logging interpretation, especially determining whether the reservoir contains water, has always been a difficult problem in mud logging. Therefore, there is an urgent need for various new methods and means to solve the current problems.

[0024] The thermal evaporation hydrocarbon gas chromatography analysis technology is a technology widely used in the field of petroleum geology. In previous research, the characteristics of the reservoir were mainly determined by analyzing and studying parameters such as the peak shape of n-alkanes, carbon number range, main peak carbon, and vertical changes in the reservoir. However, the carbon number distribution characteristics of the unidentifiable substances accompanying them have not been applied. In this technology, the complex hydrocarbon mixture generated by rock pyrolysis is separated into monomeric hydrocarbons, and then, based on the changes in monomeric n-alkanes, the properties of the crude oil in the reservoir, oil-bearing characteristics, etc. are evaluated to quickly distinguish the fluid properties. All along, this technology has not involved the application of data on unidentifiable substances other than n-alkanes. The main reasons are as follows: (1) There are certain difficulties in naming and reading the values of unidentifiable substances that appear irregularly; (2) There are no available research results on the role of unidentifiable substances.

[0025] In the process of implementing the present invention, based on continuous observation and experimentation, the inventors found that there is a certain correlation between unidentifiable substances and the water content in the oil layer. Considering the total hydrocarbon content in the thermal evaporation hydrocarbon as the basis for determining the crude oil content in the reservoir can obtain more accurate reservoir crude oil characteristics. Therefore, there is an urgent need for a method to obtain reservoir crude oil characteristics based on all thermal evaporation hydrocarbons.

[0026] Therefore, to solve the above problems, an embodiment of the present invention proposes a method and system for identifying reservoir types based on thermal evaporation hydrocarbons. The method first obtains the hydrocarbon mixture contained in the rock sample taken from the reservoir to be identified, and respectively identifies the n-alkanes and unidentifiable substances other than the identified n-alkanes in the hydrocarbon mixture; then, respectively obtains the total structure peak of the hydrocarbon mixture, the first chromatographic peak of the n-alkanes, and the second chromatographic peak of the unidentifiable substances; finally, determines the reservoir type according to the percentage of the second chromatographic peak area in the total structure peak area and the ratio between the second chromatographic peak area and the first chromatographic peak area. The present invention effectively improves the accuracy of oil-water identification and realizes the rapid and accurate identification of reservoir types. At the same time, the present invention enriches the judgment means for comprehensively interpreting oil, gas, and water layers in logging, can be widely applied to the judgment link of reservoir water flooding status in the field of oil and gas exploration and development, assists in comprehensive interpretation and evaluation, and as a scientific and efficient oil-water identification means, effectively improves the logging interpretation accuracy.

[0027] Example 1

[0028] Figure 1 This is the step diagram of the method for identifying reservoir types based on thermal evaporation hydrocarbons according to the embodiments of the present application. The following refers to Figure 1 to illustrate each step of this method.

[0029] As Figure 1As shown, in step S110, a rock sample taken from the reservoir to be identified is heated, and the hydrocarbon mixture generated during the heating process is collected. In the embodiment of the present application, based on the thermal evaporation hydrocarbon chromatography analysis technology that combines rock pyrolysis and gas chromatography, a rock sample is first collected from the reservoir to be identified, and then the collected rock sample is heated to collect the hydrocarbon mixture generated during the heating process, so as to obtain thermal evaporation hydrocarbons.

[0030] In the step of heating a rock sample taken from the reservoir to be identified and collecting the hydrocarbon mixture generated during the heating process, the rock sample is placed in a pyrolysis furnace for heating, and when the temperature in the pyrolysis furnace reaches a constant temperature of 300 °C, the collection of the hydrocarbon mixture begins. Specifically, in this embodiment, the rock sample taken from the reservoir to be identified is first placed in a pyrolysis furnace, and then the heating temperature of the pyrolysis furnace is gradually increased until the temperature in the pyrolysis furnace reaches 300 °C and remains at a constant temperature of 300 °C, and the collection process of the hydrocarbon mixture is started.

[0031] Further, in step S120, the hydrocarbon mixture is separated into multiple monomeric hydrocarbons, and then the n-alkanes therein are identified. In practical applications, the hydrocarbon mixture is composed of various types of monomeric hydrocarbons. Therefore, in this embodiment, the hydrocarbon mixture is separated into multiple monomeric hydrocarbons, and the saturated hydrocarbons in the current multiple monomeric hydrocarbons are determined to identify the n-alkanes in the multiple monomeric hydrocarbons, so as to use the identified n-alkanes to determine the reservoir type.

[0032] In a specific embodiment of the present application, capillary gas chromatography column technology is used to analyze the composition of the hydrocarbon mixture, so as to separate the hydrocarbon mixture into multiple monomeric hydrocarbons. In this embodiment, the collected hydrocarbon mixture is analyzed for its composition through a capillary gas chromatography column to achieve efficient separation of multiple monomeric hydrocarbons. Accordingly, after separating the hydrocarbon mixture with complex composition into individual monomeric hydrocarbons and then identifying them, the n-alkanes can be efficiently identified.

[0033] In a specific embodiment of the present application, the remaining monomeric hydrocarbons that are not identified as n-alkanes are used as non-identifiable substances, where the non-identifiable substances include, but are not limited to: isoparaffins, naphthenes, and aromatic hydrocarbons.

[0034] Further, in step S130, the chromatographic peaks of each monomeric hydrocarbon are obtained, and then all the chromatographic peaks are integrated into a total peak representing the content of hydrocarbon mixtures in the oil and gas components of the reservoir to be identified, and the chromatographic peaks of n-alkanes with a specified carbon number range are integrated into a first chromatographic peak representing the content of n-alkanes. Based on this, a second chromatographic peak representing the content of unidentifiable substances is obtained. After separating the hydrocarbon mixture into multiple monomeric hydrocarbons, in this embodiment, the chromatographic peaks of each monomeric hydrocarbon are obtained, and all the chromatographic peaks are integrated to obtain a total peak, so as to represent the content of hydrocarbon mixtures in the oil and gas components of the reservoir to be identified with the total peak. Among them, by using the general peak area integration algorithm in the chromatographic field, the content of hydrocarbon mixtures in the oil and gas components of the reservoir to be identified can be obtained from the total peak area. After identifying the n-alkanes, in this embodiment, the chromatographic peaks of n-alkanes with a specified carbon number range are obtained and integrated to obtain a first chromatographic peak, so as to represent the content of n-alkanes in the oil and gas components of the reservoir to be identified with the first chromatographic peak. Among them, by using the general peak area integration algorithm in the chromatographic field, the content of n-alkanes in the oil and gas components of the reservoir to be identified can be obtained from the first chromatographic peak area. Accordingly, the first chromatographic peak representing the content of n-alkanes is removed from the total peak representing the content of hydrocarbon mixtures, and the remaining chromatographic peak is the second chromatographic peak representing the content of unidentifiable substances. In this way, by using the general peak area integration algorithm in the chromatographic field, the content of unidentifiable substances in the oil and gas components of the reservoir to be identified can be obtained from the second chromatographic peak area.

[0035] In the embodiment of the present application, the unidentifiable substances are named by region, that is: the sum of unidentifiable substances between every two n-alkanes is named to obtain a partial second chromatographic peak between every two n-alkanes. For example: the unidentifiable substances between n-alkane C13 and C14 are named "C13-C14" to obtain a partial second chromatographic peak located between n-alkane C13 and C14. Further, by superimposing the peak areas of each partial second chromatographic peak and analyzing and comparing the superimposed result with the second chromatographic peak area obtained by removing the first chromatographic peak from the total peak, the second chromatographic peak area is corrected, so as to effectively improve the comprehensive interpretation accuracy by using the corrected second chromatographic peak area.

[0036] In the embodiment of the present application, the chromatographic peaks of n-alkanes with a specified carbon number range are obtained by a gas chromatograph. Among them, the specified carbon number range is C12~C40.

[0037] Further, in step S140, the reservoir type is determined based on the percentage of the second chromatographic peak area in the total peak area and the ratio between the second chromatographic peak area and the first chromatographic peak area. In this embodiment, after obtaining the total peak, the first chromatographic peak, and the second chromatographic peak respectively, the percentage of the second chromatographic peak area in the total peak area and the ratio between the second chromatographic peak area and the first chromatographic peak area are calculated, so as to assist in the comprehensive interpretation and evaluation of the oil-gas-water layer of the reservoir according to the percentage of the second chromatographic peak area in the total peak area and the ratio between the second chromatographic peak area and the first chromatographic peak area, so as to realize the determination of the current reservoir type.

[0038] In a specific embodiment of the present application, for a reservoir with a known reservoir type of oil layer, taking the percentage of the second chromatographic peak area in the total peak area and the ratio between the second chromatographic peak area and the first chromatographic peak area as the ordinate and the serial number related to the generation order of the thermal evaporation hydrocarbon data as the abscissa, a corresponding data distribution cluster diagram is established. According to the established data distribution cluster diagram, when the reservoir type is determined to be an oil layer, the percentage of the second chromatographic peak area in the total peak area mostly distributes below 40%, while the ratio between the second chromatographic peak area and the first chromatographic peak area is between 0.06 and 0.67. By analyzing one by one the percentage of the abnormal second chromatographic peak area in the total peak area that distributes above 40%, it is determined that the cause of the abnormal data is the misalignment of the chromatographic peak spectrum and the heavy oil in the oil layer, which is not representative. Therefore, in this embodiment, the current abnormal data is removed, and the remaining percentage of the second chromatographic peak area in the total peak area (that is, the percentage data of the second chromatographic peak area in the total peak area that distributes below 40%) is used as normal data to identify the reservoir type of the oil layer, ensuring the accuracy of the basic data for identifying the oil layer and laying a foundation for obtaining an accurate oil layer identification result.

[0039] In a specific embodiment of the present application, for a reservoir with a known reservoir type of oil-bearing water layer, taking the percentage of the second chromatographic peak area in the total peak area and the ratio between the second chromatographic peak area and the first chromatographic peak area as the ordinate, and the serial number related to the generation sequence of the thermal evaporation hydrocarbon data as the abscissa, a corresponding data distribution cluster diagram is established. According to the established data distribution cluster diagram, when the reservoir type is determined to be an oil-bearing water layer, the percentage of the second chromatographic peak area in the total peak area mostly distributes above 50%, while the ratio between the second chromatographic peak area and the first chromatographic peak area is between 0.93 and 18.45. By analyzing one by one the percentage of the abnormal second chromatographic peak area that distributes below 50% in the total peak area, it is determined that the cause of the abnormal data is the misalignment of the chromatographic peak spectrum, which is not representative. Therefore, the current abnormal data is removed, and the remaining percentage of the second chromatographic peak area in the total peak area (that is, the percentage data of the second chromatographic peak area in the total peak area that distributes above 50%) is used as normal data to identify the reservoir type of the oil-bearing water layer, ensuring the accuracy of the basic data for identifying the oil-bearing water layer and laying a foundation for obtaining an accurate identification result of the oil-bearing water layer.

[0040] Further, during the process of determining the reservoir type, if the percentage of the second chromatographic peak area in the total peak area satisfies the first ratio range and the ratio between the second chromatographic peak area and the first chromatographic peak area satisfies the second ratio range, then the reservoir type is determined to be an oil layer, where the first ratio range is 5% - 40% and the second ratio range is 0.06 - 0.67; if the percentage of the second chromatographic peak area in the total peak area satisfies the third ratio range and the ratio between the second chromatographic peak area and the first chromatographic peak area satisfies the fourth ratio range, then the reservoir type is determined to be an oil-bearing water layer, where the third ratio range is 50% - 95% and the fourth ratio range is 0.93 - 18.45.

[0041] Specifically, in this embodiment, when the percentage of the second chromatographic peak area in the total peak area is in the range of 5% - 40% and the ratio between the second chromatographic peak area and the first chromatographic peak area is in the range of 0.06 - 0.67, the reservoir type is determined to be an oil layer. Or, when the percentage of the second chromatographic peak area in the total peak area is in the range of 50% - 95% and the ratio between the second chromatographic peak area and the first chromatographic peak area is in the range of 0.93 - 18.45, the reservoir type is determined to be an oil-bearing water layer.

[0042] After determining the reservoir type, the reservoir type identification method of the present invention also collects the percentage data of the second chromatographic peak area corresponding to multiple identified different types of reservoirs in the total peak area, and analyzes the actual oil content and actual water content of each reservoir according to the corresponding second chromatographic peak area, so as to obtain the first correlation between the percentage data of the second chromatographic peak area and the oil content or water content. After completing the type identification of multiple different types of reservoirs, this embodiment collects the percentage data of the second chromatographic peak area corresponding to multiple identified different types of reservoirs in the total peak area, and analyzes the actual oil content and actual water content of each reservoir according to the corresponding second chromatographic peak area. Through analysis, it is obtained that the more oil the reservoir contains, the smaller the percentage of the second chromatographic peak area in the total peak area, and the more water the reservoir contains, the larger the percentage of the second chromatographic peak area in the total peak area. Thus, the first correlation between the percentage data of the second chromatographic peak area and the oil content or water content is obtained, that is: the percentage data of the second chromatographic peak area is inversely proportional to the oil content and directly proportional to the water content.

[0043] Furthermore, the reservoir type identification method of the present invention also obtains the second correlation between the unidentifiable substance content and the oil content or water content according to the first correlation. According to the first correlation, it is obtained that the more oil the reservoir contains, the smaller the percentage of the second chromatographic peak area in the total peak area, and the more water the reservoir contains, the larger the percentage of the second chromatographic peak area in the total peak area. Further inference shows the second correlation between the unidentifiable substance content and the oil content or water content, that is: the unidentifiable substance content is inversely proportional to the oil content and directly proportional to the water content.

[0044] In a specific embodiment of the present application, both the well logging interpretation and the oil testing results of Well A1 show that the current reservoir is an oil reservoir. Well A1 is a reservoir with a well depth of 3446.00 m and a lithology of brownish-gray oil-stained fine conglomerate. In this reservoir, the crude oil is unevenly distributed, the oil-bearing area accounts for 35%, and the fluorescence drop illumination is bright yellow. Among them, the percentage of the second chromatographic peak area in the total peak area is 29.60% (meeting the first ratio range), and it is determined that the current reservoir is an oil reservoir. Thus, it can be seen that the first ratio range established by the present invention is reasonable and achieves the expected goal.

[0045] In another specific embodiment of the present application, both the logging interpretation and the oil testing results of Well A2 indicate that the current reservoir is an oil-bearing and water-bearing layer. Well A2 has a reservoir with a well depth of 1486.00 m and a lithology of brownish-grey oil-stained fine conglomerate. In this reservoir, the crude oil is unevenly distributed in patches, and the oil-bearing area accounts for 10%. Among them, the percentage of the area of the second chromatographic peak in the total peak area is 83.70% (meeting the third ratio range), and it is determined that the current reservoir is an oil-bearing and water-bearing layer. Thus, it can be seen that the third ratio range established by the present invention is reasonable and achieves the expected goal.

[0046] Example 2

[0047] Based on the reservoir type identification method based on thermal evaporation hydrocarbons described in the above-mentioned Embodiment 1, the embodiment of the present invention further provides a reservoir type identification system based on thermal evaporation hydrocarbons. Figure 2 It is a module block diagram of the reservoir type identification system based on thermal evaporation hydrocarbons according to the embodiment of the present application.

[0048] As Figure 2 shown, the reservoir type identification system based on thermal evaporation hydrocarbons in the embodiment of the present invention includes: a product collection module 21, a hydrocarbon type identification module 22, a chromatographic peak acquisition module 23, and a reservoir type determination module 24. The product collection module 21 is implemented according to the method described in the above step S110, and is configured to heat the rock sample taken from the reservoir to be identified and collect the hydrocarbon mixture generated during the heating process; the hydrocarbon type identification module 22 is implemented according to the method described in the above step S120, and is configured to separate the hydrocarbon mixture into multiple monomeric hydrocarbons and then identify the n-alkanes among them; the chromatographic peak acquisition module 23 is implemented according to the method described in the above step S130, and is configured to obtain the chromatographic peak of each monomeric hydrocarbon, and then integrate all the chromatographic peaks into a total peak characterizing the content of the hydrocarbon mixture in the oil and gas components of the reservoir to be identified, and integrate the chromatographic peaks of the n-alkanes with a specified carbon number range into a first chromatographic peak characterizing the content of the n-alkanes. Based on this, a second chromatographic peak characterizing the content of the unidentifiable substances is obtained; the reservoir type determination module 24 is implemented according to the method described in the above step S140, and is configured to determine the reservoir type according to the percentage of the area of the second chromatographic peak in the total peak area and the ratio between the area of the second chromatographic peak and the area of the first chromatographic peak.

[0049] Further, the reservoir type identification system in the embodiments of the present invention further includes a data processing module. The data processing module is configured to, after determining the reservoir type, collect the percentage data of the second chromatographic peak areas corresponding to multiple identified different types of reservoirs in the total peak area, and analyze the actual oil content and actual water content of each reservoir according to the corresponding second chromatographic peak areas, so as to obtain the first correlation relationship between the percentage data of the second chromatographic peak areas and the oil content or water content, wherein the percentage data of the second chromatographic peak areas is inversely proportional to the oil content and directly proportional to the water content.

[0050] The present invention discloses a method and system for identifying reservoir types based on thermally evaporated hydrocarbons. The method first obtains the hydrocarbon mixture contained in the rock sample taken from the reservoir to be identified, and respectively identifies the n-alkanes and the unidentifiable substances other than the identified n-alkanes in the hydrocarbon mixture; then, respectively obtains the total peak of the hydrocarbon mixture, the first chromatographic peak of the n-alkanes, and the second chromatographic peak of the unidentifiable substances; finally, determines the reservoir type according to the percentage of the second chromatographic peak area in the total peak area and the ratio between the second chromatographic peak area and the first chromatographic peak area. The present invention effectively improves the accuracy of oil-water identification and realizes the rapid and accurate identification of reservoir types. At the same time, the present invention enriches the judgment means for comprehensively interpreting oil and gas water layers in mud logging, can be widely applied to the judgment link of reservoir water flooding status in the field of oil and gas exploration and development, assists in comprehensive interpretation and evaluation, and as a scientific and efficient oil-water identification means, effectively improves the logging interpretation accuracy.

[0051] As described above, only the specific preferred embodiments of the present invention are provided, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

[0052] Certainly, the present invention may also have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention, but these corresponding changes and deformations should all belong to the protection scope of the claims of the present invention.

[0053] Those skilled in the art should understand that the various modules or steps of the present invention described above can be implemented by a general-purpose computing device. They can be concentrated on a single computing device or distributed over a network composed of multiple computing devices. Optionally, they can be implemented with program code executable by the computing device, so that they can be stored in a storage device and executed by the computing device, or they can be separately fabricated into individual integrated circuit modules, or multiple modules or steps among them can be fabricated into a single integrated circuit module for implementation. Thus, the present invention is not limited to any specific combination of hardware and software.

[0054] Although the embodiments disclosed in the present invention are as described above, the above content is only an embodiment adopted for the convenience of understanding the present invention and is not intended to limit the present invention. Any person skilled in the art within the technical field to which the present invention pertains can make any modifications and changes in the form of implementation and details without departing from the spirit and scope disclosed by the present invention. However, the scope of patent protection of the present invention shall still be subject to the scope defined by the appended claims.

Claims

1. A reservoir type identification method based on thermal evaporation of hydrocarbons, characterized in that: include: Heating a rock sample taken from a reservoir to be identified and collecting a hydrocarbon mixture produced during the heating process; Separating the hydrocarbon mixture into a plurality of monomeric hydrocarbons, and then identifying normal alkanes therein; Obtaining the chromatographic peak of each monomer hydrocarbon, and then integrating all the chromatographic peaks into a total peak characterizing the content of hydrocarbon mixtures in the oil and gas components of the reservoir to be identified, and integrating the chromatographic peak of normal alkanes with a specified carbon number range into a first chromatographic peak characterizing the content of normal alkanes, based on which, obtaining a second chromatographic peak characterizing the content of unidentifiable substances; The reservoir type is determined according to the percentage of the second chromatographic peak area in the total chromatographic peak area and the ratio of the second chromatographic peak area to the first chromatographic peak area.

2. The reservoir type identification method according to claim 1, characterized in that: The remaining monomer hydrocarbons that are not identified as normal alkanes are regarded as unidentifiable substances, and the unidentifiable substances include but are not limited to isoalkanes, cycloalkanes and aromatic hydrocarbons.

3. The reservoir type identification method according to claim 1 or 2, characterized in that: The components of the hydrocarbon mixture are analyzed by using a capillary chromatography column technique, so as to separate the hydrocarbon mixture into a plurality of monomer hydrocarbons.

4. The reservoir type identification method according to any one of claims 1 to 3, characterized in that: The specified carbon number range is C12 to C40.

5. The reservoir type identification method according to any one of claims 1 to 4, characterized in that: The process of determining the reservoir type includes: If the percentage of the second chromatographic peak area in the total peak area satisfies a first ratio range, and the ratio of the second chromatographic peak area to the first chromatographic peak area satisfies a second ratio range, then the reservoir type is determined to be an oil layer, wherein the first ratio range is 5% to 40%, and the second ratio range is 0.06 to 0.67; If the percentage of the second chromatographic peak area in the total peak area satisfies the third ratio range, and the ratio of the second chromatographic peak area to the first chromatographic peak area satisfies the fourth ratio range, then the reservoir type is determined to be an oil-bearing water layer, wherein the third ratio range is 50% to 95%, and the fourth ratio range is 0.93 to 18.

45.

6. The reservoir type identification method according to any one of claims 1 to 5, characterized in that: After determining the reservoir type, the reservoir type identification method further includes: The percentage data of the second chromatographic peak area corresponding to a plurality of identified different types of reservoirs in the total peak area are collected, and the actual oil content and the actual water content of each reservoir are analyzed according to the corresponding second chromatographic peak area to obtain a first correlation between the second chromatographic peak area percentage data and the oil content or the water content, wherein: The second chromatographic peak area ratio data is inversely proportional to the oil content and directly proportional to the water content.

7. The reservoir type identification method according to claim 6, characterized in that: The reservoir type identification method further includes: According to the first correlation, a second correlation between the unrecognizable matter content and the oil content or the water content is obtained, wherein: The content of the unrecognizable matter is inversely proportional to the oil content and directly proportional to the water content.

8. The reservoir type identification method according to any one of claims 1 to 7, characterized in that: The step of heating a rock sample taken from a reservoir to be identified and collecting a hydrocarbon mixture produced during the heating process includes: The rock sample is placed in a pyrolysis furnace for heating, and when the temperature in the pyrolysis furnace reaches a constant temperature of 300° C., the hydrocarbon mixture is collected.

9. A reservoir type identification system based on thermal evaporation hydrocarbons, characterized in that: The reservoir type identification system includes the following modules: A product collection module, which is used to heat the rock sample taken from the reservoir to be identified and collect the hydrocarbon mixture produced during the heating process; A hydrocarbon type identification module, which is used to separate the hydrocarbon mixture into a plurality of monomer hydrocarbons and then identify normal alkanes therein; A chromatographic peak acquisition module, which is used to acquire the chromatographic peak of each monomer hydrocarbon, and then integrate all the chromatographic peaks into a total peak characterizing the content of hydrocarbon mixtures in the oil and gas components of the reservoir to be identified, and integrate the chromatographic peaks of normal alkanes with a specified carbon number range into a first chromatographic peak characterizing the content of normal alkanes, based on which, a second chromatographic peak characterizing the content of unidentifiable substances is obtained; The reservoir type determination module is used to determine the reservoir type according to the percentage of the second chromatographic peak area in the total chromatographic peak area and the ratio between the second chromatographic peak area and the first chromatographic peak area.

10. The reservoir type identification system according to claim 9, characterized in that: The reservoir type identification system further includes: A data processing module is used to collect the percentage data of the second chromatographic peak area corresponding to multiple identified different types of reservoirs in the total peak area after determining the reservoir type, and analyze the actual oil content and actual water content of each reservoir according to the corresponding second chromatographic peak area to obtain a first correlation between the second chromatographic peak area percentage data and the oil content or the water content, wherein the second chromatographic peak area percentage data is inversely proportional to the oil content and is directly proportional to the water content.

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