Fluid identification method and system, terminal device, and machine-readable storage medium

Abstract

Provided are a fluid identification method and system, a terminal device, and a machine-readable storage medium, belonging to the field of petroleum exploration. The method comprises: determining a study sample logging curve, a gas logging curve and drilling detection parameters; on the basis of the study sample logging curve, establishing a shallow resistivity and deep resistivity cross plot, and identifying water from among unknown fluids; using the gas logging curve to establish a derived parameter cross plot; using the study sample logging curve and the drilling detection parameters to establish a semi-quantitative evaluation chart of CO2 content based on density porosity and neutron porosity, and a semi-quantitative evaluation chart of CO2 content based on density porosity and porosity difference; on the basis of the derived parameter cross plot, the semi-quantitative evaluation chart of CO2 content based on density porosity and neutron porosity, and the semi-quantitative evaluation chart of CO2 content based on density porosity and porosity difference, identifying CO2, condensate gas and oil in the unknown fluids. By means of the provided method, unknown fluids can be accurately identified, and logging interpretation evaluation accuracy is improved.

Description

Fluid identification methods, systems, terminal devices, and machine-readable storage media

[0001] Cross-reference to related applications

[0002] This application claims the benefit of Chinese Patent Application No. 202411416344.0, filed on October 11, 2024, the contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to the field of petroleum exploration technology, specifically to a fluid identification method, a fluid identification system, a terminal device, and a machine-readable storage medium. Background Technology

[0004] During oil and gas exploration in the Santos Basin of Brazil, the western South China Sea oilfields, and the Songliao and Bohai Seas, non-hydrocarbon gases, primarily CO2, are frequently encountered, with some oilfields or gas reservoirs containing extremely high concentrations. To identify CO2 in oil and gas reservoirs, fluid samples are typically obtained through formation testing for analysis; however, this process is time-consuming and costly. Therefore, to reduce exploration costs, using logging-while-drilling (WWD) and wireline logging data combined with well logging data obtained during drilling is a crucial method for identifying complex fluid properties. Well logging fluid identification has always been a key issue in reservoir logging evaluation and is fundamental to reservoir assessment.

[0005] Currently, conventional fluid property identification methods are widely used both domestically and internationally. However, identifying fluids such as non-hydrocarbon gas layers, condensate gas layers, and volatile oil layers dominated by supercritical CO2 remains challenging. Since the beginning of the 21st century, with the discovery of high-CO2 gas fields in the western South China Sea, the Changde gas field in the Songliao Basin, and the Qinnan Depression in the Bohai Sea, domestic scholars have gradually deepened their research on the identification of CO2-containing fluid properties. Early research primarily focused on identifying CO2 gas from hydrocarbon gases dominated by methane and condensate gas. Conventional identification methods involved qualitatively identifying fluid properties using cross-plots constructed from conventional well logging data, such as quantitatively identifying CO2 based on component analysis models. With the emergence of increasingly complex fluid properties, scholars are continuously utilizing other well logging and testing data for fluid property identification. This includes calculating the gas-oil ratio using well logging data, using gas logging values ​​from well logging information, and comparing total hydrocarbon background values ​​and total hydrocarbon tailing values ​​to identify fluid properties.

[0006] After decades of development, fluid identification methods for CO2, condensate, and hydrocarbon gases have been applied and promoted in domestic basins. However, these methods are generally applied to sandstone reservoirs with shallow burial depths (below 2000m) and high reservoir porosity (15-30%). When reservoirs are buried deeper and have strong heterogeneity in lithology and physical properties, complex pore-throat structures, and irregular distribution of oil, gas, and water, although the fluid properties are different, they are extremely similar in logging performance, resulting in weak logging response characteristics. This makes it difficult to distinguish and identify them using conventional methods, greatly increasing the difficulty and economic benefits of exploration, development, and evaluation. Summary of the Invention

[0007] To address the problem that existing technologies often have weak logging response characteristics, which hinder the identification of unknown fluids, this invention provides a fluid identification method, a fluid identification system, a terminal device, and a machine-readable storage medium. This method can accurately identify unknown fluids, improve the accuracy of logging interpretation and evaluation, and effectively conduct research on reservoir logging evaluation, sedimentary reservoirs, and reservoir classification. In particular, it reduces exploration difficulty and improves economic efficiency in deep-water carbonate oil and gas exploration.

[0008] To achieve the above objectives, the first aspect of the present invention provides a fluid identification method, comprising the following steps: determining a well logging curve of a research sample, a gas logging curve of a research sample, and drilling detection parameters; establishing a cross-plot of shallow resistivity and deep resistivity based on the well logging curve of the research sample; identifying water from an unknown fluid based on the cross-plot of shallow resistivity and deep resistivity; establishing a cross-plot of derived parameters using the gas logging curve of the research sample; establishing a semi-quantitative CO2 content evaluation chart of density porosity and neutron porosity and a semi-quantitative CO2 content evaluation chart of density porosity and porosity difference using the well logging curve of the research sample and the drilling detection parameters; and identifying CO2, condensate gas, and oil in an unknown fluid based on the cross-plot of derived parameters, the semi-quantitative CO2 content evaluation chart of density porosity and neutron porosity, and the semi-quantitative CO2 content evaluation chart of density porosity and porosity difference.

[0009] Furthermore, the well logging curves and gas logging curves of the research sample are determined by the following method: obtaining initial well logging curves and initial gas logging curves; extracting initial well logging curves and initial gas logging curves corresponding to the detection depth of drilling detection from the initial well logging curves and initial gas logging curves; and screening the initial well logging curves and initial gas logging curves corresponding to the detection depth of drilling detection to obtain the well logging curves and gas logging curves of the research sample.

[0010] Furthermore, the initial logging curves include: initial caliper curve, initial natural gamma logging curve, initial neutron logging curve, initial density logging curve, initial sonic logging curve, initial NMR total porosity, and initial NMR total porosity while drilling curve; the initial gas logging curves include: initial methane curve, initial ethane curve, initial propane curve, initial butane curve, initial pentane curve, and total hydrocarbon curve; the research sample logging curves include: deep resistivity curve, shallow resistivity curve, neutron logging curve, density logging curve, and NMR total porosity while drilling curve; the research sample gas logging curves include: methane curve, ethane curve, propane curve, butane curve, pentane curve, and total hydrocarbon curve.

[0011] Furthermore, the step of establishing a cross-plot of shallow resistivity and deep resistivity based on the well logging curves of the research sample includes: constructing the cross-plot of shallow resistivity and deep resistivity based on the deep resistivity curve and the shallow resistivity curve.

[0012] Further, the step of establishing a cross-plot of derived parameters using the gas logging curves of the research sample includes: obtaining derived parameters based on the gas logging curves of the research sample; wherein, the derived parameters include: hydrocarbon moisture ratio, hydrocarbon balance ratio, dryness coefficient, and methane ratio; establishing a cross-plot of methane ratio versus dryness coefficient based on the methane ratio and the dryness coefficient; establishing a cross-plot of methane ratio versus hydrocarbon moisture balance ratio based on the methane ratio and the hydrocarbon moisture balance ratio; wherein, the hydrocarbon moisture balance ratio is the ratio of the hydrocarbon moisture ratio to the hydrocarbon balance ratio.

[0013] Furthermore, the hydrocarbon moisture ratio is obtained by the following method: W h =100×(C2+C3+C4+C5) / (C1+C2+C3+C4+C5);

[0014] Among them, W h The hydrocarbon moisture ratio is given, where C1 is the methane content, C2 is the ethane content, C3 is the propane content, C4 is the butane content, and C5 is the pentane content.

[0015] The hydrocarbon balance ratio is obtained through the following method: B h = (C1+C2) / (C3+C4+C5);

[0016] Among them, B h The hydrocarbon balance ratio is mentioned above;

[0017] The drying coefficient is C1 / TG; where TG = C1 + C2 + C3 + C4 + C5;

[0018] The methane ratio is C1 / (C2+C3+C4+C5).

[0019] Furthermore, the step of establishing a semi-quantitative evaluation chart of CO2 content based on density porosity and neutron porosity, and a semi-quantitative evaluation chart of CO2 content based on density porosity and porosity difference, using the well logging curves of the research samples and the drilling detection parameters, includes: determining the density porosity curve and the porosity difference curve; establishing the semi-quantitative evaluation chart of CO2 content based on density porosity and neutron porosity using the neutron logging curves, the density porosity curves, and the drilling detection parameters; and establishing the semi-quantitative evaluation chart of CO2 content based on density porosity and porosity difference using the porosity difference curves, the density porosity curves, and the drilling detection parameters.

[0020] Furthermore, the step of establishing a semi-quantitative evaluation chart of CO2 content using density porosity and neutron porosity based on the neutron logging curve, the density porosity curve, and the drilling detection parameters includes: establishing a cross-plot of density porosity and neutron porosity based on the neutron logging curve and the density logging curve; and marking intervals in the cross-plot of density porosity and neutron porosity based on the drilling detection parameters to obtain the semi-quantitative evaluation chart of CO2 content using density porosity and neutron porosity.

[0021] Furthermore, the step of establishing a semi-quantitative evaluation chart of CO2 content based on density porosity and porosity difference using the porosity difference curve, the density porosity curve, and the drilling detection parameters includes: establishing a cross-plot of density porosity and porosity difference based on the porosity difference curve and the density logging curve; and marking intervals in the cross-plot of density porosity and porosity difference based on the drilling detection parameters to obtain the semi-quantitative evaluation chart of CO2 content based on density porosity and porosity difference.

[0022] A second aspect of the present invention provides a fluid identification system, the fluid identification system comprising: a parameter determination module for determining well logging curves of a research sample, gas logging curves of a research sample, and drilling detection parameters; establishing a cross-plot of shallow resistivity and deep resistivity based on the well logging curves of the research sample; identifying water from an unknown fluid based on the cross-plot of shallow resistivity and deep resistivity; establishing a derived parameter cross-plot using the gas logging curves of the research sample; establishing a semi-quantitative CO2 content evaluation chart of density porosity and neutron porosity and a semi-quantitative CO2 content evaluation chart of density porosity and porosity difference using the well logging curves of the research sample and the drilling detection parameters; and an unknown fluid identification module for identifying CO2, condensate gas, and oil in an unknown fluid based on the derived parameter cross-plot, the semi-quantitative CO2 content evaluation chart of density porosity and neutron porosity and the semi-quantitative CO2 content evaluation chart of density porosity and porosity difference.

[0023] Furthermore, the well logging curves and gas logging curves of the research sample are determined by the following method: obtaining initial well logging curves and initial gas logging curves; extracting initial well logging curves and initial gas logging curves corresponding to the detection depth of drilling detection from the initial well logging curves and initial gas logging curves; and screening the initial well logging curves and initial gas logging curves corresponding to the detection depth of drilling detection to obtain the well logging curves and gas logging curves of the research sample.

[0024] Furthermore, the initial logging curves include: initial caliper curve, initial natural gamma logging curve, initial neutron logging curve, initial density logging curve, initial sonic logging curve, initial NMR total porosity, and initial NMR total porosity while drilling curve; the initial gas logging curves include: initial methane curve, initial ethane curve, initial propane curve, initial butane curve, initial pentane curve, and total hydrocarbon curve; the research sample logging curves include: deep resistivity curve, shallow resistivity curve, neutron logging curve, density logging curve, and NMR total porosity while drilling curve; the research sample gas logging curves include: methane curve, ethane curve, propane curve, butane curve, pentane curve, and total hydrocarbon curve.

[0025] Furthermore, the step of establishing a cross-plot of shallow resistivity and deep resistivity based on the well logging curves of the research sample includes: constructing the cross-plot of shallow resistivity and deep resistivity based on the deep resistivity curve and the shallow resistivity curve.

[0026] Further, the step of establishing a cross-plot of derived parameters using the gas logging curves of the research sample includes: obtaining derived parameters based on the gas logging curves of the research sample; wherein, the derived parameters include: hydrocarbon moisture ratio, hydrocarbon balance ratio, dryness coefficient, and methane ratio; establishing a cross-plot of methane ratio versus dryness coefficient based on the methane ratio and the dryness coefficient; establishing a cross-plot of methane ratio versus hydrocarbon moisture balance ratio based on the methane ratio and the hydrocarbon moisture balance ratio; wherein, the hydrocarbon moisture balance ratio is the ratio of the hydrocarbon moisture ratio to the hydrocarbon balance ratio.

[0027] Furthermore, the hydrocarbon moisture ratio is obtained by the following method: W h =100×(C2+C3+C4+C5) / (C1+C2+C3+C4+C5);

[0028] Among them, W h The hydrocarbon moisture ratio is given, where C1 is the methane content, C2 is the ethane content, C3 is the propane content, C4 is the butane content, and C5 is the pentane content.

[0029] The hydrocarbon balance ratio is obtained through the following method: B h = (C1+C2) / (C3+C4+C5);

[0030] Among them, B h The hydrocarbon balance ratio is mentioned above;

[0031] The drying coefficient is C1 / TG; where TG = C1 + C2 + C3 + C4 + C5;

[0032] The methane ratio is C1 / (C2+C3+C4+C5).

[0033] Furthermore, the step of establishing a semi-quantitative evaluation chart of CO2 content based on density porosity and neutron porosity, and a semi-quantitative evaluation chart of CO2 content based on density porosity and porosity difference, using the well logging curves of the research samples and the drilling detection parameters, includes: determining the density porosity curve and the porosity difference curve; establishing the semi-quantitative evaluation chart of CO2 content based on density porosity and neutron porosity using the neutron logging curves, the density porosity curves, and the drilling detection parameters; and establishing the semi-quantitative evaluation chart of CO2 content based on density porosity and porosity difference using the porosity difference curves, the density porosity curves, and the drilling detection parameters.

[0034] Furthermore, the step of establishing a semi-quantitative evaluation chart of CO2 content using density porosity and neutron porosity based on the neutron logging curve, the density porosity curve, and the drilling detection parameters includes: establishing a cross-plot of density porosity and neutron porosity based on the neutron logging curve and the density logging curve; and marking intervals in the cross-plot of density porosity and neutron porosity based on the drilling detection parameters to obtain the semi-quantitative evaluation chart of CO2 content using density porosity and neutron porosity.

[0035] Furthermore, the step of establishing a semi-quantitative evaluation chart of CO2 content based on density porosity and porosity difference using the porosity difference curve, the density porosity curve, and the drilling detection parameters includes: establishing a cross-plot of density porosity and porosity difference based on the porosity difference curve and the density logging curve; and marking intervals in the cross-plot of density porosity and porosity difference based on the drilling detection parameters to obtain the semi-quantitative evaluation chart of CO2 content based on density porosity and porosity difference.

[0036] A third aspect of the present invention provides a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the fluid recognition method described above.

[0037] A fourth aspect of the present invention provides a machine-readable storage medium storing instructions that, when executed by a processor, configure the processor to perform the fluid identification method described above.

[0038] The present invention has at least the following technical effects through the technical solution provided by the present invention:

[0039] The invented fluid volume identification method first determines the well logging curves, gas logging curves, and drilling detection parameters of the research sample. Then, based on the well logging curves of the research sample, a cross-plot of shallow resistivity and deep resistivity is established, and water is identified from the unknown fluid based on this cross-plot. Next, a derived parameter cross-plot is established using the gas logging curves of the research sample. Furthermore, semi-quantitative CO2 content evaluation charts based on density porosity and neutron porosity, and semi-quantitative CO2 content evaluation charts based on density porosity and porosity difference are established using the well logging curves and drilling detection parameters. Based on the derived parameter cross-plot, the semi-quantitative CO2 content evaluation charts based on density porosity and neutron porosity, and the semi-quantitative CO2 content evaluation charts based on density porosity and porosity difference, CO2, condensate gas, and oil in the unknown fluid are identified. The method provided by this invention can accurately identify unknown fluids, improve the accuracy of well logging interpretation and evaluation, and effectively carry out research on reservoir well logging evaluation, sedimentary reservoirs, and reservoir classification. In particular, it can reduce exploration difficulty and improve economic benefits in deep-sea carbonate oil and gas exploration.

[0040] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0041] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0042] Figure 1 is a flowchart of the fluid identification method provided in an embodiment of the present invention;

[0043] Figure 2 is a flowchart of a fluid identification method provided in another embodiment of the present invention;

[0044] Figure 3 is a logging columnar section in the fluid identification method provided in an embodiment of the present invention;

[0045] Figure 4 is a cross-plot of shallow resistivity and deep resistivity in the fluid identification method provided in the embodiment of the present invention;

[0046] Figure 5 is a cross-plot of methane ratio and dryness coefficient in the fluid identification method provided in the embodiment of the present invention;

[0047] Figure 6 is a cross-plot of the methane ratio and hydrocarbon humidity balance ratio in the fluid identification method provided in the embodiment of the present invention;

[0048] Figure 7 is a graph showing the semi-quantitative evaluation of CO2 content using density porosity and neutron porosity in the fluid identification method provided in the embodiment of the present invention.

[0049] Figure 8 is a graph showing the semi-quantitative evaluation of CO2 content using density porosity and porosity difference in the fluid identification method provided in this embodiment of the invention. Detailed Implementation

[0050] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0051] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0052] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used to describe the relative positions of components in relation to the directions shown in the accompanying drawings or in relation to the vertical, perpendicular, or gravitational directions.

[0053] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0054] Please refer to Figure 1. This embodiment of the invention provides a fluid identification method, which includes the following steps: S101: Determine the well logging curve of the research sample, the gas logging curve of the research sample, and the drilling detection parameters; S102: Establish a cross-plot of shallow resistivity and deep resistivity based on the well logging curve of the research sample; S103: Identify water from the unknown fluid based on the cross-plot of shallow resistivity and deep resistivity; S104: Establish a cross-plot of derived parameters using the gas logging curve of the research sample; S105: Establish a semi-quantitative CO2 content evaluation chart based on density porosity and neutron porosity, and a semi-quantitative CO2 content evaluation chart based on density porosity and porosity difference, using the well logging curve of the research sample and the drilling detection parameters; S106: Identify CO2, condensate gas, and oil in the unknown fluid based on the cross-plot of derived parameters, the semi-quantitative CO2 content evaluation chart based on density porosity and neutron porosity, and the semi-quantitative CO2 content evaluation chart based on density porosity and porosity difference.

[0055] Specifically, the first step is to perform step S101: determine the well logging curve of the study sample, the gas logging curve of the study sample, and the drilling detection parameters for drilling detection.

[0056] Furthermore, the well logging curves and gas logging curves of the research sample are determined by the following method: obtaining initial well logging curves and initial gas logging curves; extracting initial well logging curves and initial gas logging curves corresponding to the detection depth of drilling detection from the initial well logging curves and initial gas logging curves; and screening the initial well logging curves and initial gas logging curves corresponding to the detection depth of drilling detection to obtain the well logging curves and gas logging curves of the research sample.

[0057] Furthermore, the initial logging curves include: initial caliper curve, initial natural gamma logging curve, initial neutron logging curve, initial density logging curve, initial sonic logging curve, initial NMR total porosity, and initial NMR total porosity while drilling curve; the initial gas logging curves include: initial methane curve, initial ethane curve, initial propane curve, initial butane curve, initial pentane curve, and total hydrocarbon curve; the research sample logging curves include: deep resistivity curve, shallow resistivity curve, neutron logging curve, density logging curve, and NMR total porosity while drilling curve; the research sample gas logging curves include: methane curve, ethane curve, propane curve, butane curve, pentane curve, and total hydrocarbon curve.

[0058] Specifically, in this embodiment of the invention, initial logging curves and initial gas logging curves of the target layer in the study area are obtained. The initial logging curves include: initial caliper curve (CAL), initial natural gamma ray logging curve (GR), initial neutron logging curve (NPHI), initial density logging curve (RHOB), initial acoustic logging curve (AC), initial total nuclear magnetic resonance porosity (MPHS), initial nuclear magnetic resonance-while-drilling (MPHS-LWD) total nuclear magnetic resonance porosity curve, initial deep resistivity curve, and initial shallow resistivity curve, etc. The initial logging curves and initial gas logging curves are preprocessed, quality analyzed, and standardized to remove the influence of wellbore enlargement, outliers, and systematic deviations caused by measurements from different logging instruments.

[0059] Obtain drilling inspection parameters, including formation testing (MDT), flash separation experiments, and well testing (DST) conclusions. Determine the inspection depth for drilling inspection, including depth points or depth segments. Extract initial logging curves and initial gas logging curves corresponding to the inspection depth from the initial logging curves and initial gas logging curves, using them as typical research samples. Screen the initial logging curves and initial gas logging curves corresponding to the inspection depth to obtain the research sample logging curves and research sample gas logging curves. Preferably, the well logging curves of the research samples include: deep resistivity curves (AT90, RD, or RT90, etc.), shallow resistivity curves (AT20, RS, or RT20, etc.), neutron logging curves (NPHI), density logging curves (RHOB), and total porosity curves (MPHS-LWD) obtained while drilling; the initial gas logging curves include: initial methane curve, initial ethane curve, initial propane curve, initial butane curve, initial pentane curve, and total hydrocarbon curve; the gas logging curves of the research samples include: methane curve C1, ethane curve C2, propane curve C3, butane curve C4, pentane curve C5, and total hydrocarbon curve TG. Among them, the methane curve C1 represents methane (CH4), the simplest hydrocarbon and one of the main components of natural gas; the ethane curve C2 represents ethane (C2H6), a light hydrocarbon and also an important component of natural gas; the propane curve C3 represents propane (C3H8), another common component of natural gas; the butane curve C4 includes iC4 and nC4. iC4 is the isomer C4, referring to isomer hydrocarbons with four carbon atoms, such as isobutane (i-C4H8), and nC4 is the normal-form C4, referring to normal-form hydrocarbons with four carbon atoms, such as n-butane (n-C4H8). 10 C5 includes: nC5, where nC5 is the normal C5, referring to a normal hydrocarbon with five carbon atoms, such as n-pentane (n-C5H). 12 TG usually refers to the total composition of gaseous hydrocarbons, that is, the total amount of all gaseous hydrocarbons.

[0060] Next, step S102 is executed: a cross-plot of shallow resistivity and deep resistivity is established based on the well logging curves of the research sample.

[0061] Next, step S103 is performed: water is identified from the unknown fluid based on the cross-plot of shallow and deep resistivity.

[0062] Furthermore, the step of establishing a cross-plot of shallow resistivity and deep resistivity based on the well logging curves of the research sample includes: constructing the cross-plot of shallow resistivity and deep resistivity based on the deep resistivity curve and the shallow resistivity curve.

[0063] Specifically, in this embodiment of the invention, deep resistivity curves and shallow resistivity curves are extracted from the well logging curves of the research sample, and a cross-plot of shallow resistivity and deep resistivity is constructed based on the deep resistivity curves and shallow resistivity curves. Water is identified from unknown fluids based on the cross-plot of shallow resistivity and deep resistivity.

[0064] Next, proceed to step S104: Use the gas logging curves of the research sample to establish a cross-plot of derived parameters.

[0065] Further, the step of establishing a cross-plot of derived parameters using the gas logging curves of the research sample includes: obtaining derived parameters based on the gas logging curves of the research sample; wherein, the derived parameters include: hydrocarbon moisture ratio, hydrocarbon balance ratio, dryness coefficient, and methane ratio; establishing a cross-plot of methane ratio versus dryness coefficient based on the methane ratio and the dryness coefficient; establishing a cross-plot of methane ratio versus hydrocarbon moisture balance ratio based on the methane ratio and the hydrocarbon moisture balance ratio; wherein, the hydrocarbon moisture balance ratio is the ratio of the hydrocarbon moisture ratio to the hydrocarbon balance ratio.

[0066] Furthermore, the hydrocarbon moisture ratio is obtained by the following method: W h =100×(C2+C3+C4+C5) / (C1+C2+C3+C4+C5);

[0067] Among them, W h The hydrocarbon moisture ratio is given, where C1 is the methane content, C2 is the ethane content, C3 is the propane content, C4 is the butane content, and C5 is the pentane content.

[0068] The hydrocarbon balance ratio is obtained through the following method: B h = (C1+C2) / (C3+C4+C5);

[0069] Among them, B h The hydrocarbon balance ratio is mentioned above;

[0070] The drying coefficient is C1 / TG; where TG = C1 + C2 + C3 + C4 + C5;

[0071] The methane ratio is C1 / (C2+C3+C4+C5).

[0072] Specifically, in this embodiment of the invention, gas logging curves of research samples are selected. Based on gas logging methods for identifying fluid properties, such as the hydrocarbon component triangle diagram method, the 3H ratio method, and the correlation between 3H parameters and derived parameters, derived parameters are determined from the gas logging curves of the research samples. These derived parameters include: hydrocarbon moisture ratio W. h Hydrocarbon balance ratio B h The methane ratio C1 / (C2+C3+C4+C5) and the dryness coefficient C1 / TG, where TG = C1+C2+C3+C4+C5. Hydrocarbon moisture ratio W.h = 100 × (C2 + C3 + C4 + C5) / (C1 + C2 + C3 + C4 + C5), where C1 is the methane content, C2 is the ethane content, C3 is the propane content, C4 is the butane content, and C5 is the pentane content. Hydrocarbon balance ratio B h = (C1+C2) / (C3+C4+C5). The hydrocarbon moisture balance ratio is W. h / B h .

[0073] Based on the hydrocarbon humidity balance ratio W h / B h To amplify the relationship between oil and gas, and simultaneously utilize the methane ratio C1 / (C2+C3+C4+C5) to pinpoint complex oil and gas characteristics, cross-plots are created. These include cross-plots based on the methane ratio and aridity coefficient, and cross-plots based on the methane ratio and hydrocarbon moisture balance ratio, namely, the C1 / (C2+C3+C4+C5)-C1 / TG cross-plot and the C1 / (C2+C3+C4+C5)-W cross-plot. h / B h Cross plot. Establish interpretation criteria and preliminarily identify oil or condensate gas and CO2 gas based on the cross plot with derived parameters.

[0074] Next, proceed to step S105: using the well logging curves of the research sample and the drilling detection parameters, establish a semi-quantitative evaluation chart of CO2 content based on density porosity and neutron porosity, and a semi-quantitative evaluation chart of CO2 content based on the difference between density porosity and porosity.

[0075] Furthermore, the step of establishing a semi-quantitative evaluation chart of CO2 content based on density porosity and neutron porosity, and a semi-quantitative evaluation chart of CO2 content based on density porosity and porosity difference, using the well logging curves of the research samples and the drilling detection parameters, includes: determining the density porosity curve and the porosity difference curve; establishing the semi-quantitative evaluation chart of CO2 content based on density porosity and neutron porosity using the neutron logging curves, the density porosity curves, and the drilling detection parameters; and establishing the semi-quantitative evaluation chart of CO2 content based on density porosity and porosity difference using the porosity difference curves, the density porosity curves, and the drilling detection parameters.

[0076] Furthermore, the step of establishing a semi-quantitative evaluation chart of CO2 content using density porosity and neutron porosity based on the neutron logging curve, the density porosity curve, and the drilling detection parameters includes: establishing a cross-plot of density porosity and neutron porosity based on the neutron logging curve and the density logging curve; and marking intervals in the cross-plot of density porosity and neutron porosity based on the drilling detection parameters to obtain the semi-quantitative evaluation chart of CO2 content using density porosity and neutron porosity.

[0077] Furthermore, the step of establishing a semi-quantitative evaluation chart of CO2 content based on density porosity and porosity difference using the porosity difference curve, the density porosity curve, and the drilling detection parameters includes: establishing a cross-plot of density porosity and porosity difference based on the porosity difference curve and the density logging curve; and marking intervals in the cross-plot of density porosity and porosity difference based on the drilling detection parameters to obtain the semi-quantitative evaluation chart of CO2 content based on density porosity and porosity difference.

[0078] Finally, step S106 is executed: based on the derived parameter cross plot, the semi-quantitative evaluation chart of CO2 content by density porosity and neutron porosity, and the semi-quantitative evaluation chart of CO2 content by density porosity and porosity difference, CO2, condensate gas, and oil in the unknown fluid are identified.

[0079] Specifically, in this embodiment of the invention, the density porosity curve and the porosity difference curve are determined: PHIE D =(DEN-D ma ) / (D f -D ma ), of which PHIE D Density porosity, DEN is the density logging value (g / cm³). 3 ), D ma Density value of the rock skeleton (g / cm³) 3 ), D f Fluid density value (g / cm³) 3 Porosity difference The relation is: Among them PHIE D The value is density porosity, and MPHS-LWD is total porosity measured by NMR during drilling. The unit is V / V.

[0080] Neutron porosity (NPHI) and density porosity (RHOB) logging curves were selected from the well logging curves of the research samples to establish a cross plot of density porosity and neutron porosity. Then, drilling detection parameters such as formation testing (MDT), flash separation experiment, and deep testing (DST) were used to mark the intervals in the cross plot of density porosity and neutron porosity to obtain a semi-quantitative evaluation chart of CO2 content based on density porosity and neutron porosity, and to conduct a semi-quantitative evaluation of CO2 in the target layer of the study area.

[0081] Based on the porosity difference curve and density logging curve, a cross plot of density porosity and porosity difference is established. Then, drilling detection parameters such as formation testing (MDT), flash separation test, and well testing (DST) are used to mark the intervals in the cross plot of density porosity and porosity difference, resulting in a semi-quantitative evaluation chart of CO2 content based on density porosity and porosity difference.

[0082] The logging response characteristics of supercritical CO2 gas and oil are similar. The density of CO2 gas is between 0.85-0.9 g / cm³. 3 The density of CO2 is similar to that of oil, therefore density logging responds weakly to supercritical CO2. The most significant difference in response characteristics lies in the hydrogen content index. CO2 does not contain hydrogen atoms, and its hydrogen content index H... CO2 The value is 0; the density of crude oil is 0.85 g / cm³. 3 Generally, the hydrogen content index H is considered to be oil The hydrogen index H of methane gas is 1.05. CH4 The value is 0.55. Both neutron logging and nuclear magnetic resonance (NMR) logging measure the hydrogen content index in the fluid. The higher the CO2 content, the lower the hydrogen content index, the greater the difference between neutron porosity and density porosity, and the more pronounced the "envelope" characteristic of the neutron-density curve. Therefore, a semi-quantitative evaluation of CO2 can be performed based on the cross-plot of density porosity and neutron porosity. NMR logging not only measures the hydrogen content index in the fluid but is also only sensitive to hydrogen in the pore fluid. While drilling NMR reflects the true fluid properties of the formation, density porosity reflects the formation porosity after mud intrusion, soaking, etc. The difference in porosity between the two has a good positive correlation with CO2 content. In the case of drilling NMR logging, a semi-quantitative evaluation of CO2 can be performed using the cross-plot of density porosity and the porosity difference.

[0083] While the cross-plot of density porosity versus neutron porosity has low interval discrimination, this method is universally applicable. The cross-plot of density porosity versus porosity difference compensates for the shortcomings of the density porosity versus neutron porosity cross-plot and the influence of mud intrusion, improving the accuracy of semi-quantitative CO2 content identification. If the reservoir is deep and has low porosity (porosity less than 6%), the identification effect is poor. Better porosity and physical properties result in better discrimination.

[0084] Finally, CO2, condensate gas, and oil were identified from the unknown fluid by combining the positions of the points in the cross plot of derived parameters, the semi-quantitative evaluation chart of CO2 content by density porosity and neutron porosity, and the semi-quantitative evaluation chart of CO2 content by density porosity and porosity difference.

[0085] This invention makes full use of gas logging data and innovatively integrates a method for identifying complex fluids in logging, including semi-quantitative evaluation of supercritical CO2 fluids and complex fluid identification technology. It can effectively identify complex fluids containing supercritical CO2, with high discrimination accuracy and good applicability. It is effective for reservoir logging evaluation, sedimentary reservoirs, reservoir classification and other studies, especially in deep-water carbonate oil and gas exploration in the ocean, reducing exploration difficulty and improving economic benefits.

[0086] Example

[0087] This embodiment utilizes well logging curves, gas logging curves, and drilling detection parameters to identify fluids in the subsalt lacustrine carbonate reservoirs of the Santos Basin in the Brazilian sea area. The identification steps are as follows:

[0088] Initial logging curves and initial gas logging curves for the target formation in the study area were obtained. The initial logging curves included: initial caliper log (CAL), initial natural gamma ray log (GR), initial neutron log (NPHI), initial density log (RHOB), initial acoustic log (AC), initial total nuclear magnetic resonance porosity (MPHS), initial MPHS-LWD, initial deep resistivity curve, and initial shallow resistivity curve. The initial logging curves and initial gas logging curves underwent preprocessing, quality analysis, and standardization to remove the effects of wellbore enlargement, outliers, and systematic biases caused by different logging instruments.

[0089] Drilling detection parameters were obtained, including formation testing (MDT), flash separation experiments, and well testing (DST) conclusions. The detection depth for drilling was determined, including 238 depth points or depth segments in the target drilled formation within the region. Initial logging curves and initial gas logging curves corresponding to the detection depth were extracted from the initial logging curves and initial gas logging curves, serving as typical research samples. The initial logging curves and initial gas logging curves corresponding to the detection depth were then screened to obtain the research sample logging curves and research sample gas logging curves. Preferably, the well logging curves of the research samples include: deep resistivity curves (AT90, RD or RT90, etc.), shallow resistivity curves (AT20, RS or RT20, etc.), neutron logging curves (NPHI), density logging curves (RHOB), and total porosity curves (MPHS-LWD) obtained by drilling; the gas logging curves of the research samples include: methane curve C1, ethane curve C2, propane curve C3, butane curve C4, pentane curve C5, and total hydrocarbon curve TG.

[0090] Please refer to Figure 3. Figure 3 is the logging column of well L-1 in the Santos Basin, Brazil, from X600 to X850m. Formation testing in the X600-X690m section showed the fluid to be oil containing 44% CO2. MDT fluid sampling in the X750-X770m section confirmed the fluid to be water. The first track is the total gas (TG) logging curve; the second is the methane (C1) curve; the third is the gamma ray logging curve (GR); the fourth is the density porosity (RHOB) and neutron logging curves (NPHI); the fifth is the deep resistivity (AT90) and shallow resistivity (AT20) curves; and the sixth is the total porosity (MPHS-LWD) and density porosity (PHIE) curves from the drilling nuclear magnetic resonance (NMR) data. DThe seventh step is the conclusion of the DST oil test.

[0091] Deep resistivity curves (AT90) and shallow resistivity curves (AT20) were extracted from the well logging curves of the research samples. Based on these curves, a cross-plot of shallow resistivity AT20 and deep resistivity AT90, as shown in Figure 4, was constructed. In the figure, the X650-X680m segment falls within the oil, condensate gas, and CO2 region, while the X750-X780m segment falls within the water layer. Both the deep and shallow resistivity are less than 20 ohms. Therefore, the fluid property in the X750-X780m segment can be determined to be water. Based on the cross-plot, a water layer interpretation standard was established: when AT90 < 22 ohms and AT20 < 29 ohms, the fluid property is water; when AT90 ≥ 22 ohms and AT20 ≥ 29 ohms, the fluid property is oil, condensate gas, or supercritical CO2 gas.

[0092] By selecting gas logging curves from the research samples, and using gas logging methods for identifying fluid properties, such as the hydrocarbon component triangle diagram method, the 3H ratio method, and the correlation between 3H parameters and derived parameters, derived parameters were determined from the gas logging curves of the research samples. These derived parameters include the hydrocarbon moisture ratio (W). h Hydrocarbon balance ratio B h The methane ratio C1 / (C2+C3+C4+C5) and the dryness coefficient C1 / TG, where TG = C1+C2+C3+C4+C5. Hydrocarbon moisture ratio W. h = 100 × (C2 + C3 + C4 + C5) / (C1 + C2 + C3 + C4 + C5), where C1 is the methane content, C2 is the ethane content, C3 is the propane content, C4 is the butane content, and C5 is the pentane content. Hydrocarbon balance ratio B h = (C1+C2) / (C3+C4+C5). The hydrocarbon moisture balance ratio is W. h / B h .

[0093] Based on the hydrocarbon humidity balance ratio W h / B h To amplify the relationship between oil and gas, and simultaneously utilize the methane ratio C1 / (C2+C3+C4+C5) to pinpoint complex oil and gas characteristics, cross-plots are generated. These include Figure 5, which shows a cross-plot between methane ratio and aridity coefficient, and Figure 6, which shows a cross-plot between methane ratio and hydrocarbon moisture balance ratio, i.e., the C1 / (C2+C3+C4+C5)-C1 / TG cross-plot and the C1 / (C2+C3+C4+C5)-W cross-plot. h / B h Intersection diagram.

[0094] A total of 5 CO2 gas points, 15 oil layer points, and 3 condensate gas points (some not shown) were collected from 15 wells in 3 pre-salt oil and gas fields. An interpretation model suitable for identifying complex pre-salt fluids in the Santos Basin, Brazil, was developed, and interpretation criteria were established: when C1 / (C2+C3+C4+C5)>7.5, the fluid property is oil or condensate gas; when C1 / (C2+C3+C4+C5)≤7.5, the interpretation layer gas measurement data were plotted on Figures 5 and 6, and CO2 gas was preliminarily and quickly identified based on the location of the plotted points.

[0095] Figure 5 shows the cross-plot of C1 / (C2+C3+C4+C5)-C1 / TG in the X650-X680m segment of well X-1, and Figure 6 shows the cross-plot of C1 / (C2+C3+C4+C5)-W. h / B h The cross plot shows the point falling within the oil or condensate gas region on the chart. Therefore, the fluid in the X650-X680m section can be identified as oil or condensate gas.

[0096] Determine the density-porosity curve and the porosity difference curve: PHIE D =(DEN-D ma ) / (D f -D ma ), among which, PHIE D Density porosity, DEN is the density logging value (g / cm³). 3 ), D ma Density value of the rock skeleton (g / cm³) 3 ), D f Fluid density value (g / cm³) 3 Porosity difference The relation is: Among them PHIE D The value is density porosity, and MPHS-LWD is total porosity measured by NMR during drilling. The unit is V / V.

[0097] Neutron porosity (NPHI) and density porosity (RHOB) logging curves were selected from the well logging curves of the research samples to establish a cross plot of density porosity and neutron porosity. Then, drilling detection parameters such as formation testing (MDT), flash separation experiment, and oil testing (DST) were used to mark the intervals in the cross plot of density porosity and neutron porosity, resulting in the CO2 content semi-quantitative evaluation chart of density porosity and neutron porosity shown in Figure 7. The CO2 semi-quantitative evaluation of the target interval in the study area was carried out.

[0098] Based on the porosity difference curve and density logging curve, a cross-plot of density porosity and porosity difference was established. Then, drilling detection parameters such as formation testing (MDT), flash separation experiment, and deep testing (DST) were used to mark the intervals in the cross-plot of density porosity and porosity difference, resulting in the semi-quantitative evaluation chart of CO2 content based on density porosity and porosity difference shown in Figure 8. The fluid nature was preliminarily determined to be oil based on the location of the droplet.

[0099] The logging response characteristics of supercritical CO2 gas and oil are similar. The density of CO2 gas is between 0.85-0.9 g / cm³. 3 The density of CO2 is similar to that of oil, therefore density logging responds weakly to supercritical CO2. The most significant difference in response characteristics lies in the hydrogen content index. CO2 does not contain hydrogen atoms, and its hydrogen content index H... CO2 The value is 0; the density of crude oil is 0.85 g / cm³. 3 Generally, the hydrogen content index H is considered to be oil The hydrogen index H of methane gas is 1.05. CH4 The value is 0.55. Both neutron logging and nuclear magnetic resonance (NMR) logging measure the hydrogen content index in the fluid. The higher the CO2 content, the lower the hydrogen content index, the greater the difference between neutron porosity and density porosity, and the more pronounced the "envelope" characteristic of the neutron-density curve. Therefore, a semi-quantitative evaluation of CO2 can be performed based on the cross-plot of density porosity and neutron porosity. NMR logging not only measures the hydrogen content index in the fluid but is also only sensitive to hydrogen in the pore fluid. While drilling NMR reflects the true fluid properties of the formation, density porosity reflects the formation porosity after mud intrusion, soaking, etc. The difference in porosity between the two has a good positive correlation with CO2 content. In the case of drilling NMR logging, a semi-quantitative evaluation of CO2 can be performed using the cross-plot of density porosity and the porosity difference.

[0100] While the cross-plot of density porosity versus neutron porosity has low interval discrimination, this method is universally applicable. The cross-plot of density porosity versus porosity difference compensates for the shortcomings of the density porosity versus neutron porosity cross-plot and the influence of mud intrusion, improving the accuracy of semi-quantitative CO2 content identification. If the reservoir is deep and has low porosity (porosity less than 6%), the identification effect is poor. Better porosity and physical properties result in better discrimination.

[0101] Finally, using the derived parameter cross-plot and the CO2 content determined in the above steps, the fluid type is identified, and CO2, condensate gas, and oil are identified from the unknown fluid. In this embodiment, Figures 5 and 6 are the C1 / (C2+C3+C4+C5)-C1 / TG cross-plot and C1 / (C2+C3+C4+C5)-W cross-plots for the X650-X680m segment of well X-1, respectively. h / B hThe cross-plot shows that the drop point falls within the oil or condensate gas region on the chart. Therefore, the fluid properties in the X650-X680m section can be determined to be either oil or condensate gas. Figure 7 shows a semi-quantitative evaluation chart of CO2 content based on density porosity and neutron porosity in the X650-X680m section of well L-1. Based on the drop point's location, the fluid properties are initially determined to be oil. Figure 8 shows a semi-quantitative evaluation chart of CO2 content based on density porosity and porosity difference in the X650-X680m section of well L-1. Based on the drop point's location, the fluid properties are initially determined to be oil.

[0102] A second aspect of the present invention provides a fluid identification system, the fluid identification system comprising: a parameter determination module for determining well logging curves of a research sample, gas logging curves of a research sample, and drilling detection parameters; establishing a cross-plot of shallow resistivity and deep resistivity based on the well logging curves of the research sample; identifying water from an unknown fluid based on the cross-plot of shallow resistivity and deep resistivity; establishing a derived parameter cross-plot using the gas logging curves of the research sample; establishing a semi-quantitative CO2 content evaluation chart of density porosity and neutron porosity and a semi-quantitative CO2 content evaluation chart of density porosity and porosity difference using the well logging curves of the research sample and the drilling detection parameters; and an unknown fluid identification module for identifying CO2, condensate gas, and oil in an unknown fluid based on the derived parameter cross-plot, the semi-quantitative CO2 content evaluation chart of density porosity and neutron porosity and the semi-quantitative CO2 content evaluation chart of density porosity and porosity difference.

[0103] Furthermore, the well logging curves and gas logging curves of the research sample are determined by the following method: obtaining initial well logging curves and initial gas logging curves; extracting initial well logging curves and initial gas logging curves corresponding to the detection depth of drilling detection from the initial well logging curves and initial gas logging curves; and screening the initial well logging curves and initial gas logging curves corresponding to the detection depth of drilling detection to obtain the well logging curves and gas logging curves of the research sample.

[0104] Furthermore, the initial logging curves include: initial caliper curve, initial natural gamma logging curve, initial neutron logging curve, initial density logging curve, initial sonic logging curve, initial NMR total porosity, and initial NMR total porosity while drilling curve; the initial gas logging curves include: initial methane curve, initial ethane curve, initial propane curve, initial butane curve, initial pentane curve, and total hydrocarbon curve; the research sample logging curves include: deep resistivity curve, shallow resistivity curve, neutron logging curve, density logging curve, and NMR total porosity while drilling curve; the research sample gas logging curves include: methane curve, ethane curve, propane curve, butane curve, pentane curve, and total hydrocarbon curve.

[0105] Furthermore, the step of establishing a cross-plot of shallow resistivity and deep resistivity based on the well logging curves of the research sample includes: constructing the cross-plot of shallow resistivity and deep resistivity based on the deep resistivity curve and the shallow resistivity curve.

[0106] Further, the step of establishing a cross-plot of derived parameters using the gas logging curves of the research sample includes: obtaining derived parameters based on the gas logging curves of the research sample; wherein, the derived parameters include: hydrocarbon moisture ratio, hydrocarbon balance ratio, dryness coefficient, and methane ratio; establishing a cross-plot of methane ratio versus dryness coefficient based on the methane ratio and the dryness coefficient; establishing a cross-plot of methane ratio versus hydrocarbon moisture balance ratio based on the methane ratio and the hydrocarbon moisture balance ratio; wherein, the hydrocarbon moisture balance ratio is the ratio of the hydrocarbon moisture ratio to the hydrocarbon balance ratio.

[0107] Furthermore, the hydrocarbon moisture ratio is obtained by the following method: W h =100×(C2+C3+C4+C5) / (C1+C2+C3+C4+C5);

[0108] Among them, W h The hydrocarbon moisture ratio is given, where C1 is the methane content, C2 is the ethane content, C3 is the propane content, C4 is the butane content, and C5 is the pentane content.

[0109] The hydrocarbon balance ratio is obtained through the following method: B h = (C1+C2) / (C3+C4+C5);

[0110] Among them, B h The hydrocarbon balance ratio is mentioned above;

[0111] The drying coefficient is C1 / TG; where TG = C1 + C2 + C3 + C4 + C5;

[0112] The methane ratio is C1 / (C2+C3+C4+C5).

[0113] Furthermore, the step of establishing a semi-quantitative evaluation chart of CO2 content based on density porosity and neutron porosity, and a semi-quantitative evaluation chart of CO2 content based on density porosity and porosity difference, using the well logging curves of the research samples and the drilling detection parameters, includes: determining the density porosity curve and the porosity difference curve; establishing the semi-quantitative evaluation chart of CO2 content based on density porosity and neutron porosity using the neutron logging curves, the density porosity curves, and the drilling detection parameters; and establishing the semi-quantitative evaluation chart of CO2 content based on density porosity and porosity difference using the porosity difference curves, the density porosity curves, and the drilling detection parameters.

[0114] Furthermore, the step of establishing a semi-quantitative evaluation chart of CO2 content using density porosity and neutron porosity based on the neutron logging curve, the density porosity curve, and the drilling detection parameters includes: establishing a cross-plot of density porosity and neutron porosity based on the neutron logging curve and the density logging curve; and marking intervals in the cross-plot of density porosity and neutron porosity based on the drilling detection parameters to obtain the semi-quantitative evaluation chart of CO2 content using density porosity and neutron porosity.

[0115] Furthermore, the step of establishing a semi-quantitative evaluation chart of CO2 content based on density porosity and porosity difference using the porosity difference curve, the density porosity curve, and the drilling detection parameters includes: establishing a cross-plot of density porosity and porosity difference based on the porosity difference curve and the density logging curve; and marking intervals in the cross-plot of density porosity and porosity difference based on the drilling detection parameters to obtain the semi-quantitative evaluation chart of CO2 content based on density porosity and porosity difference.

[0116] A third aspect of the present invention provides a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the fluid recognition method described above.

[0117] A fourth aspect of the present invention provides a machine-readable storage medium storing instructions that, when executed by a processor, configure the processor to perform the fluid identification method described above.

[0118] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0119] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately. Furthermore, various different embodiments of the present invention can also be arbitrarily combined, as long as they do not violate the spirit of the present invention, and should also be regarded as the content disclosed by the present invention.

Claims

A fluid identification method, characterized in that, The fluid identification method includes: Determine the well logging curves, gas logging curves, and drilling detection parameters for the research samples; Based on the well logging curves of the research samples, a cross-plot of shallow resistivity and deep resistivity was established; Based on the cross plot of shallow and deep resistivity, water is identified from unknown fluids; A cross-plot of derived parameters was constructed using the gas logging curves of the research sample. Using the well logging curves of the research samples and the drilling detection parameters, semi-quantitative evaluation charts of CO2 content based on density porosity and neutron porosity and semi-quantitative evaluation charts of CO2 content based on the difference between density porosity and porosity were established. Based on the cross plot of the derived parameters, the semi-quantitative evaluation chart of CO2 content using density porosity and neutron porosity, and the semi-quantitative evaluation chart of CO2 content using density porosity and porosity difference, CO2, condensate gas, and oil in unknown fluids can be identified. The fluid identification method according to claim 1 is characterized in that, The well logging curves and gas logging curves of the research samples were determined in the following way: Obtain the initial logging curves and initial gas logging curves; Extract the initial logging curve and initial gas logging curve corresponding to the detection depth of the drilling detection from the initial logging curve and initial gas logging curve; The initial logging curves and initial gas logging curves corresponding to the detection depth of the drilling detection are screened to obtain the research sample logging curves and the research sample gas logging curves. The fluid identification method according to claim 2 is characterized in that, The initial logging curves include: initial caliper curve, initial natural gamma logging curve, initial neutron logging curve, initial density logging curve, initial sonic logging curve, initial nuclear magnetic resonance total porosity, and initial drilling nuclear magnetic resonance total porosity curve; The initial gas logging curves include: initial methane curve, initial ethane curve, initial propane curve, initial butane curve, initial pentane curve, and total hydrocarbon curve; The well logging curves of the research samples include: deep resistivity curves, shallow resistivity curves, neutron logging curves, density logging curves, and total porosity curves obtained by nuclear magnetic resonance during drilling. The gas logging curves of the research samples include: methane curves, ethane curves, propane curves, butane curves, pentane curves, and total hydrocarbon curves. The fluid identification method according to claim 3 is characterized in that, The establishment of a cross-plot of shallow and deep resistivity based on the well logging curves of the research sample includes: Based on the deep resistivity curve and the shallow resistivity curve, construct the intersection diagram of shallow resistivity and deep resistivity. The fluid identification method according to claim 3 is characterized in that, The process of establishing a derived parameter cross-plot using the gas logging curves of the research sample includes: Derivative parameters were obtained based on the gas logging curves of the research samples; wherein, the derived parameters include: hydrocarbon moisture ratio, hydrocarbon balance ratio, dryness coefficient, and methane ratio; A cross plot of methane ratio versus dryness coefficient is established based on the methane ratio and the dryness coefficient. A cross plot of methane ratio and hydrocarbon humidity balance ratio is established based on the methane ratio and hydrocarbon humidity balance ratio; wherein the hydrocarbon humidity balance ratio is the ratio of the hydrocarbon humidity ratio to the hydrocarbon balance ratio. The fluid identification method according to claim 5 is characterized in that, The hydrocarbon moisture ratio is obtained through the following method: W h =100×(C2+C3+C4+C5) / (C1+C2+C3+C4+C5); Among them, W h The hydrocarbon moisture ratio is given, where C1 is the methane content, C2 is the ethane content, C3 is the propane content, C4 is the butane content, and C5 is the pentane content. The hydrocarbon balance ratio is obtained through the following method: B h =(C1+C2) / (C3+C4+C5); Among them, B h The hydrocarbon balance ratio is mentioned above; The drying coefficient is C1 / TG; where TG = C1 + C2 + C3 + C4 + C5; The methane ratio is C1 / (C2+C3+C4+C5). The fluid identification method according to claim 3 is characterized in that, The method of establishing semi-quantitative CO2 content evaluation charts based on density porosity and neutron porosity, and semi-quantitative CO2 content evaluation charts based on the difference between density porosity and porosity, using well logging curves of the research samples and drilling detection parameters, includes: Determine the density-porosity curve and the porosity difference curve; A semi-quantitative evaluation chart of CO2 content based on density porosity and neutron porosity is established using the neutron logging curve, the density porosity curve, and the drilling detection parameters. A semi-quantitative evaluation chart of CO2 content based on the porosity difference curve, the density porosity curve, and the drilling detection parameters is established using the density porosity and porosity difference. The fluid identification method according to claim 7 is characterized in that, The method of establishing a semi-quantitative evaluation chart of CO2 content using density porosity and neutron porosity based on the neutron logging curve, the density porosity curve, and the drilling detection parameters includes: A cross-plot of density porosity versus neutron porosity is established based on the neutron logging curve and the density logging curve. Based on the drilling detection parameters, the intervals are marked in the intersection diagram of density porosity and neutron porosity to obtain a semi-quantitative evaluation chart of CO2 content using density porosity and neutron porosity. The fluid identification method according to claim 7 is characterized in that, The method of establishing a semi-quantitative evaluation chart of CO2 content based on the density porosity and porosity difference using the porosity difference curve, the density porosity curve, and the drilling detection parameters includes: A cross-plot of density porosity and porosity difference is established based on the porosity difference curve and the density logging curve; Based on the drilling detection parameters, the intervals are marked in the intersection diagram of density porosity and porosity difference to obtain a semi-quantitative evaluation chart of CO2 content using density porosity and porosity difference. A fluid identification system, characterized in that, The fluid identification system includes: The parameter determination module is used to determine the well logging curves of the research samples, the gas logging curves of the research samples, and the drilling detection parameters of the drilling detection. Based on the well logging curves of the research samples, a cross-plot of shallow resistivity and deep resistivity was established; Based on the cross plot of shallow and deep resistivity, water is identified from unknown fluids; A cross-plot of derived parameters was constructed using the gas logging curves of the research sample. Using the well logging curves of the research samples and the drilling detection parameters, semi-quantitative evaluation charts of CO2 content based on density porosity and neutron porosity and semi-quantitative evaluation charts of CO2 content based on the difference between density porosity and porosity were established. The unknown fluid identification module is used to identify CO2, condensate gas, and oil in unknown fluids based on the derived parameter cross plot, the CO2 content evaluation chart of density porosity and neutron porosity, and the CO2 content evaluation chart of density porosity and porosity difference. The fluid identification system according to claim 10 is characterized in that, The well logging curves and gas logging curves of the research samples were determined in the following way: Obtain the initial logging curves and initial gas logging curves; Extract the initial logging curve and initial gas logging curve corresponding to the detection depth of the drilling detection from the initial logging curve and initial gas logging curve; The initial logging curves and initial gas logging curves corresponding to the detection depth of the drilling detection are screened to obtain the research sample logging curves and the research sample gas logging curves. The fluid identification system according to claim 11 is characterized in that, The initial logging curves include: initial caliper curve, initial natural gamma logging curve, initial neutron logging curve, initial density logging curve, initial sonic logging curve, initial nuclear magnetic resonance total porosity, and initial drilling nuclear magnetic resonance total porosity curve; The initial gas logging curves include: initial methane curve, initial ethane curve, initial propane curve, initial butane curve, initial pentane curve, and total hydrocarbon curve; The well logging curves of the research samples include: deep resistivity curves, shallow resistivity curves, neutron logging curves, density logging curves, and total porosity curves obtained by nuclear magnetic resonance during drilling. The gas logging curves of the research samples include: methane curves, ethane curves, propane curves, butane curves, pentane curves, and total hydrocarbon curves. The fluid identification system according to claim 12 is characterized in that, The establishment of a cross-plot of shallow and deep resistivity based on the well logging curves of the research sample includes: Based on the deep resistivity curve and the shallow resistivity curve, construct the intersection diagram of shallow resistivity and deep resistivity. The fluid identification system according to claim 12 is characterized in that, The process of establishing a derived parameter cross-plot using the gas logging curves of the research sample includes: Derivative parameters were obtained based on the gas logging curves of the research samples; wherein, the derived parameters include: hydrocarbon moisture ratio, hydrocarbon balance ratio, dryness coefficient, and methane ratio; A cross plot of methane ratio versus dryness coefficient is established based on the methane ratio and the dryness coefficient. A cross plot of methane ratio and hydrocarbon humidity balance ratio is established based on the methane ratio and hydrocarbon humidity balance ratio; wherein the hydrocarbon humidity balance ratio is the ratio of the hydrocarbon humidity ratio to the hydrocarbon balance ratio. The fluid identification system according to claim 14 is characterized in that, The hydrocarbon moisture ratio is obtained through the following method: W h =100×(C2+C3+C4+C5) / (C1+C2+C3+C4+C5); Among them, W h The hydrocarbon moisture ratio is given, where C1 is the methane content, C2 is the ethane content, C3 is the propane content, C4 is the butane content, and C5 is the pentane content. The hydrocarbon balance ratio is obtained through the following method: B h =(C1+C2) / (C3+C4+C5); Among them, B h The hydrocarbon balance ratio is mentioned above; The drying coefficient is C1 / TG; where TG = C1 + C2 + C3 + C4 + C5; The methane ratio is C1 / (C2+C3+C4+C5). The fluid identification system according to claim 12 is characterized in that, The method of establishing semi-quantitative CO2 content evaluation charts based on density porosity and neutron porosity, and semi-quantitative CO2 content evaluation charts based on the difference between density porosity and porosity, using well logging curves of the research samples and drilling detection parameters, includes: Determine the density-porosity curve and the porosity difference curve; A semi-quantitative evaluation chart of CO2 content based on density porosity and neutron porosity is established using the neutron logging curve, the density porosity curve, and the drilling detection parameters. A semi-quantitative evaluation chart of CO2 content based on the porosity difference curve, the density porosity curve, and the drilling detection parameters is established using the density porosity and porosity difference. The fluid identification system according to claim 16 is characterized in that, The method of establishing a semi-quantitative evaluation chart of CO2 content using density porosity and neutron porosity based on the neutron logging curve, the density porosity curve, and the drilling detection parameters includes: A cross-plot of density porosity versus neutron porosity is established based on the neutron logging curve and the density logging curve. Based on the drilling detection parameters, the intervals are marked in the intersection diagram of density porosity and neutron porosity to obtain a semi-quantitative evaluation chart of CO2 content using density porosity and neutron porosity. The fluid identification system according to claim 16 is characterized in that, The method of establishing a semi-quantitative evaluation chart of CO2 content based on the density porosity and porosity difference using the porosity difference curve, the density porosity curve, and the drilling detection parameters includes: A cross-plot of density porosity and porosity difference is established based on the porosity difference curve and the density logging curve; Based on the drilling detection parameters, the intervals are marked in the intersection diagram of density porosity and porosity difference to obtain a semi-quantitative evaluation chart of CO2 content using density porosity and porosity difference. A terminal device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, it implements the fluid identification method according to any one of claims 1-9. A machine-readable storage medium storing instructions, characterized in that, When executed by a processor, this instruction causes the processor to be configured to perform the fluid identification method according to any one of claims 1-9.

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