Evaluation method for tight sandstone condensate gas layer and related device

Abstract

The invention discloses an evaluation method and a related device for a tight sandstone condensate gas layer. The evaluation method comprises the following steps: acquiring a logging aftereffect gas logging C1 peak value, a drilling gas logging C1 peak value, a drilling broken gas coefficient and a gas logging form characteristic value; the aftereffect index is constructed according to the relation between the logging aftereffect gas logging C1 peak value and the gas logging C1 peak value during drilling; constructing a gas-bearing index according to a broken gas coefficient in drilling and a gas logging form characteristic value; and the aftereffect index and the gas-bearing index intersect to establish a two-dimensional condensate gas layer evaluation layout for fluid property identification. According to the method, the correlation is analyzed, the corresponding relation between the aftereffect C1 peak value and the oil testing result is fully excavated, the idea of establishing an evaluation index by using the relation between the aftereffect gas logging C1 peak value characteristics and the gas logging C1 form during drilling and the relation between the C1 base value characteristics before and after reservoir uncovering is innovatively put forward, and the condensate gas layer evaluation model is constructed. A good effect is achieved in practical drilling application, and the fluid property identification accuracy is remarkably improved.

Description

Technical Field

[0001] The invention belongs to the field of oil and gas exploration, and particularly relates to an evaluation method and related devices for tight sandstone condensate gas layers. Background Art

[0002] In the field of oil exploration, accurate evaluation of reservoir fluids during exploration logging is extremely important for completion testing and layer selection. For the Jurassic tight sandstone condensate gas reservoir in northern Kuche, the application of traditional logging evaluation technology is not effective due to the influence of engineering factors such as drilling technology. Before the development of this patent, the commonly used condensate gas layer evaluation technologies include: (1) using seven gas logging parameters and their derived parameters during drilling to establish an evaluation chart, such as the light-heavy hydrocarbon ratio method, trigonometric method, and Pixler method; (2) using the changes in parameters such as the post-effect gas logging value, drilling fluid viscosity, chloride ion content, and the phenomenon of slot surface observation to assist in identifying gas layers.

[0003] Traditional logging evaluation methods such as the light-heavy hydrocarbon ratio method, triangle method, and Pixler method use the gas logging component parameters and their derived parameters obtained during drilling to establish evaluation charts. They use a single parameter and have poor applicability to logging evaluation of the Jurassic tight sandstone condensate gas reservoir in northern Kuche, and the interpretation conformity rate is low. The existing after-effect evaluation methods mainly use logging after-effect total hydrocarbon values, drilling fluid density, viscosity, chloride ion content and other parameters to assist in oil and gas layer evaluation, and the evaluation effect is poor. Therefore, the existing reservoir gas logging evaluation technology has poor applicability to the Jurassic tight sandstone condensate gas reservoir in northern Kuche. Summary of the invention

[0004] The object of the present invention is to provide an evaluation method and related device for tight sandstone condensate gas layers to solve the above problems.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides an evaluation method for a tight sandstone condensate gas layer, comprising:

[0007] Obtain the C1 peak value of the after-effect gas logging and the C1 peak value of the gas logging during drilling, as well as the broken gas coefficient and gas logging morphological characteristic values ​​during drilling;

[0008] The after-effect index is constructed based on the relationship between the C1 peak value of the after-effect gas logging and the C1 peak value of the gas logging during drilling;

[0009] The gas content index is constructed based on the broken gas coefficient during drilling and the gas measurement morphological characteristic value;

[0010] The after-effect index and gas content index are then combined to establish a two-dimensional condensate gas layer evaluation map for fluid property identification.

[0011] Optional, acquisition of the post-effect gas test C1 peak value and the gas test C1 peak value during drilling:

[0012] The after-effect gas measurement C1 value is obtained by real-time collection and analysis by the chromatographic analysis acquisition analyzer in the logging equipment during the after-effect detection, and the maximum value of the after-effect gas measurement C1 value is taken as the after-effect gas measurement C1 peak value; the gas measurement C1 value during drilling is obtained by real-time collection and analysis by the chromatographic analysis analyzer in the logging equipment during the drilling process, and the maximum value of the gas measurement C1 value in the oil and gas display section is taken as the gas measurement C1 peak value during drilling.

[0013] Optional, the crushing gas coefficient and gas measurement morphological characteristic values ​​during drilling:

[0014] The gas logging C1 value of the surrounding rock before drilling into the reservoir is taken as the base value before gas logging C1, the gas logging C1 value of the bottom plate after drilling through the reservoir is taken as the base value after gas logging C1, and the ratio of the base value before gas logging C1 to the base value after gas logging C1 is taken as the reservoir fragmentation gas coefficient, and its value range is >0 and ≦1. The larger the value, the more obvious the reservoir fragmentation gas characteristics are. The gas logging morphological characteristic value is described by the mean value of gas logging C1 of the reservoir, that is, the average value of the gas logging C1 value of the reservoir section is taken, combined with the change of the base value before and after gas logging C1 of the reservoir, which reflects the morphological characteristics of the reservoir gas logging C1.

[0015] Optionally, the after-effect index is constructed based on the relationship between the after-effect gas logging C1 peak value and the gas logging C1 peak value during drilling:

[0016] By counting and analyzing the after-effect gas logging C1 peak value and the gas logging C1 peak value during drilling of the condensate gas layer, low gas production layer, gas-water layer, gas-bearing water layer and water layer in the condensate gas layer block, the relationship between the after-effect gas logging C1 peak value and the gas logging C1 peak value during drilling and the empirical value of the boundary of the after-effect gas logging C1 peak value of the condensate gas layer, gas-water layer, low gas production layer, gas-bearing water layer and water layer are obtained. These relationships are quantified and calculated to obtain the after-effect index HXf, and the calculation formula is Hxf=(HXC1 / ZJC1)*(HXC1 / 20%); when there is no obvious change in the drilling fluid density during drilling and after-effect measurement, the larger the after-effect index is, the higher the probability of obtaining a valuable layer.

[0017] Optionally, the gas content index is constructed based on the crushing gas coefficient during drilling and the gas measurement morphological characteristic value:

[0018] The reservoir gas testing C1 pre-base value QJC1, gas testing C1 post-base value HJC1, and gas testing C1 average value JZC1 are quantified and calculated to obtain the reservoir gas content index HQf. The calculation formula is HQf=JZC1*(QJC1 / HJC1). The larger the reservoir gas content index, the higher the probability of obtaining a valuable layer.

[0019] Optionally, the aftereffect index and gas content index are combined to establish a two-dimensional condensate gas layer evaluation map:

[0020] With the after-effect index as the horizontal axis and the gas content index as the vertical axis, the two are intersected, and the valuable layer area and non-valuable area are divided according to the mathematical statistics of the sample points to form a condensate gas layer evaluation map.

[0021] In a second aspect, the present invention provides an evaluation system for a tight sandstone condensate gas layer, comprising:

[0022] The data acquisition module is used to obtain the C1 peak value of the after-effect gas logging and the C1 peak value of the gas logging during drilling, as well as the broken gas coefficient and gas logging morphological characteristic value during drilling;

[0023] The after-effect index construction module is used to construct the after-effect index based on the relationship between the C1 peak value of the after-effect gas logging and the C1 peak value of the gas logging during drilling;

[0024] Gas index construction module, used to construct the gas index based on the broken gas coefficient and gas measurement morphological characteristic values ​​during drilling;

[0025] The evaluation map construction module is used to intersect the after-effect index and the gas content index to establish a two-dimensional condensate gas layer evaluation map for fluid property identification.

[0026] Optional, acquisition of the post-effect gas test C1 peak value and the gas test C1 peak value during drilling:

[0027] The after-effect gas test C1 value is obtained by real-time collection and analysis by the chromatographic analysis acquisition analyzer in the logging equipment during the after-effect detection, and the maximum value of the after-effect gas test C1 value is taken as the after-effect gas test C1 peak value; the gas test C1 value during drilling is obtained by real-time collection and analysis by the chromatographic analyzer in the logging equipment during the drilling process, and the maximum value of the gas test C1 value in the oil and gas display section is taken as the gas test C1 peak value during drilling;

[0028] The after-effect index is constructed based on the relationship between the C1 peak value of the after-effect gas logging and the C1 peak value of the gas logging during drilling:

[0029] By counting and analyzing the C1 peak values ​​of the after-effect gas logging of the condensate gas layer, low gas production layer, gas-water layer, gas-bearing water layer, and water layer in the condensate gas layer block, and the C1 peak values ​​of the gas logging during drilling, the relationship between the C1 peak values ​​of the after-effect gas logging of the condensate gas layer, gas-water layer, low gas production layer, gas-bearing water layer, and water layer and the C1 peak values ​​of the gas logging during drilling, and the empirical value of the boundary of the C1 peak values ​​of the after-effect gas logging, these relationships are quantitatively calculated to obtain the after-effect index HXf, and the calculation formula is Hxf = (HXC1 / ZJC1) * (HXC1 / 20%); when there is no obvious change in the density of the drilling fluid during drilling and after-effect measurement, the larger the after-effect index, the higher the probability of obtaining a valuable layer;

[0030] The gas content index constructed based on the broken gas coefficient during drilling and the gas measurement morphological characteristic value:

[0031] The reservoir gas testing C1 pre-base value QJC1, gas testing C1 post-base value HJC1, and gas testing C1 average value JZC1 are quantified and calculated to obtain the reservoir gas content index HQf. The calculation formula is HQf=JZC1*(QJC1 / HJC1). The larger the reservoir gas content index, the higher the probability of obtaining a valuable layer.

[0032] In a third aspect, the present invention provides a computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the processor implements the steps of an evaluation method for tight sandstone condensate gas layers.

[0033] In a fourth aspect, the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of an evaluation method for tight sandstone condensate gas layers.

[0034] Compared with the prior art, the present invention has the following technical effects:

[0035] The present invention conducts a comprehensive study on the reservoir characteristics, logging gas logging display characteristics, after-effect gas logging display characteristics and other data in the area, analyzes their correlation, fully explores the corresponding relationship between the after-effect C1 peak value and the oil test result, and innovatively proposes the concept of establishing an evaluation index using the relationship between the after-effect gas logging C1 peak characteristics and the gas logging C1 morphology during drilling and the C1 base value characteristics before and after reservoir uncovering, and constructs a condensate gas layer evaluation model. The model has strong applicability in logging field, has achieved good results in actual drilling applications, and has significantly improved the accuracy of fluid property identification. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 DB5 well aftereffect index (HXf)-gas content index (HQf) condensate gas layer evaluation map.

[0037] Figure 2 TG6 well aftereffect index (HXf)-gas content index (HQf) condensate gas layer evaluation map.

[0038] Figure 3 It is a flow chart of the present invention.

[0039] Figure 4 This is a system structure diagram of the present invention. DETAILED DESCRIPTION

[0040] The present invention is further described below in conjunction with the accompanying drawings:

[0041] See also Figures 1 to 4 , an evaluation method for tight sandstone condensate gas layers, comprising:

[0042] Obtain the C1 peak value of the after-effect gas logging and the C1 peak value of the gas logging during drilling, as well as the broken gas coefficient and gas logging morphological characteristic values ​​during drilling;

[0043] The after-effect index is constructed based on the relationship between the C1 peak value of the after-effect gas logging and the C1 peak value of the gas logging during drilling;

[0044] The gas content index is constructed based on the broken gas coefficient during drilling and the gas measurement morphological characteristic value;

[0045] The after-effect index and gas content index are then combined to establish a two-dimensional condensate gas layer evaluation map for fluid property identification.

[0046] Through comprehensive research on reservoir characteristics, logging gas logging display characteristics, after-effect gas logging display characteristics and other data in this area, their correlation was analyzed, and the corresponding relationship between the after-effect C1 peak value and the oil test results was fully explored. The innovative idea of ​​using the relationship between the after-effect gas logging C1 peak characteristics and the gas logging C1 morphology during drilling and the C1 base value characteristics before and after reservoir uncovering to establish an evaluation index concept was proposed, and a condensate gas layer evaluation model was constructed. The model has strong applicability in logging field, has achieved good results in actual drilling applications, and has significantly improved the accuracy of fluid property identification.

[0047] Specific:

[0048] The present invention is an evaluation method for tight sandstone condensate gas layers, comprising an after-effect index constructed based on the relationship between the after-effect gas logging C1 peak value of logging and the gas logging C1 peak value during drilling, and a gas content index constructed using the broken gas coefficient during drilling and the gas logging morphological characteristic value, and an evaluation model established by the intersection.

[0049] The model consists of two parts: one is the calculation formula of the aftereffect index (HXf) and gas index (HQf) used to establish the model, and the other is the intuitive expression of the evaluation model - the two-dimensional chart. The calculation formula of the aftereffect index and gas index is obtained by summarizing and arranging multiple logging gas measurement parameters, combining the results of well completion and oil testing, and through mathematical statistics, sensitivity screening, and combined calculation. The selection and calculation formula of sensitive parameters reflect the core method of data processing. It is obtained using the calculation formula.

[0050] The calculation formula of the aftereffect index and gas content index is obtained by summarizing and arranging multiple logging gas measurement parameters, combining the results of well completion and oil testing, and through mathematical statistics, sensitivity screening, and combined calculation. The specific process is:

[0051] By statistically analyzing the gas logging total hydrocarbons, component parameters, and drilling fluid density of the condensate gas layer, low gas production layer, gas-water layer, gas-bearing water layer, and water layer during drilling and after-effect measurement in the condensate gas layer block, six parameters with good correlation with the evaluation of the condensate gas layer, namely, the after-effect gas logging C1 peak value, the gas logging C1 peak value during drilling, the gas logging C1 pre-base value, the gas logging C1 post-base value, and the gas logging C1 mean value, were selected. Based on the analysis and summary of the relationship between each parameter and its mutual relationship and the valuable layer (condensate gas layer, gas-water layer), and the non-valuable layer (low gas production layer, gas-bearing water layer, and water layer), the after-effect index and gas-bearing index were obtained through combined calculation. The calculation formula is as follows:

[0052] Aftereffect index Hxf = (HXC1 / ZJC1)*(HXC1 / 20%)

[0053] Gas content index HQf = JZC1*(QJC1 / HJC1)

[0054] The gas test C1 detected by the chromatograph analyzer in the logging equipment mainly comes from methane gas. Due to its low solubility in water-based drilling fluid and low adsorption rate in oil-based drilling fluid, the use of gas test C1 to evaluate oil and gas display is less affected and has a high accuracy rate.

[0055] The aftereffect index (HXf) is calculated by taking the maximum value of the aftereffect gas logging C1 peak of the reservoir section logging (HXC1) and the maximum value of the gas logging C1 peak during drilling of the reservoir section (ZJC1) as parameters.

[0056] HXC1: The maximum value of the C1 peak of the after-effect gas logging in the reservoir section; reflects the strength of the after-effect oil and gas signal; the unit is percentage.

[0057] ZJC1: The highest value of the C1 peak in gas logging during drilling in the reservoir section; reflects the strength of the oil and gas signal in the reservoir; the unit is percentage.

[0058] The gas content index (HQf) is calculated by taking the average value of the C1 peak of the gas test during the reservoir section drilling (JZC1), the average value of the C1 peak of the gas test before the reservoir is drilled (ZJC1), and the average value of the C1 peak of the gas test after the reservoir is drilled through (HJC1). Among them:

[0059] JZC1: The average value of C1 peak measured during drilling in the reservoir section; reflects the oil and gas filling degree and homogeneity of the reservoir; unit: percentage.

[0060] QJC1: The average value of C1 peak in gas logging before drilling the reservoir, i.e. the base value before C1 in gas logging; unit: percentage.

[0061] HJC1: The average value of the C1 peak in gas logging after the reservoir is penetrated, that is, the post-base value of C1 in gas logging; the ratio of the pre-base value and post-base value of C1 in gas logging can reflect the characteristics of reservoir broken gas; the unit is percentage.

[0062] On this basis, a condensate gas layer evaluation model is established, with the after-effect index (HXf) as the horizontal coordinate and the gas content index (HQf) as the vertical coordinate. The two are intersected, and the valuable layer area and the non-valuable area are divided according to the mathematical statistics of the sample points, thus forming a condensate gas layer evaluation model (see Figure 1 ). This plate can identify condensate gas layers and gas-water layers as valuable layers, and gas-water layers, low-yield gas layers, and water layers as non-valuable layers.

[0063] The calculation formula of after-effect index and gas content index is obtained through mathematical statistics, parameter extraction, sensitivity screening and combined calculation based on the data of after-effect gas logging C1 peak value, gas logging C1 peak value during drilling, gas logging C1 base value, gas logging C1 morphological characteristic value and completion test results. Therefore, the after-effect index and gas content index obtained by the calculation formula can evaluate the condensate gas layer. The selection of sensitive parameters and the calculation formula reflect the core method of data processing. The after-effect index and gas content index obtained by the calculation formula are used to establish a two-dimensional condensate gas layer evaluation model at the intersection, and the distribution areas of different fluid properties are intuitively displayed through graphics.

[0064] The patent of this invention is a condensate gas layer evaluation model based on logging after-effect parameters for the tight sandstone reservoir of the Jurassic system in northern Kuche. It is a logging-assisted evaluation technology. This set of technologies includes an implementable evaluation model, that is, an implementable evaluation plate, in which the after-effect index (HXf) and the gas content index (HQf) correspond to an interpretation plate.

[0065] After the model is implemented, the final fluid evaluation result is based on the evaluation results of the implementation chart to identify the condensate layer. The fluid evaluation result is determined by the area of ​​the model where the test point falls. Figure 1 and Figure 2 As shown in the figure, by calculating the aftereffect index and gas content index of the two wells, the fluid properties can be intuitively judged at the landing point of the logging evaluation model, and the logging interpretation is consistent with the oil testing results.

[0066] In another embodiment of the present invention, an evaluation system for tight sandstone condensate gas layers is provided, which can be used to implement the above-mentioned evaluation method for tight sandstone condensate gas layers. Specifically, the system includes:

[0067] The data acquisition module is used to obtain the C1 peak value of the after-effect gas logging and the C1 peak value of the gas logging during drilling, as well as the broken gas coefficient and gas logging morphological characteristic value during drilling;

[0068] The after-effect index construction module is used to construct the after-effect index based on the relationship between the C1 peak value of the after-effect gas logging and the C1 peak value of the gas logging during drilling;

[0069] Gas index construction module, used to construct the gas index based on the broken gas coefficient and gas measurement morphological characteristic values ​​during drilling;

[0070] The evaluation map construction module is used to intersect the after-effect index and the gas content index to establish a two-dimensional condensate gas layer evaluation map for fluid property identification.

[0071] The division of modules in the embodiments of the present invention is schematic and is only a logical function division. There may be other division methods in actual implementation. In addition, each functional module in each embodiment of the present invention may be integrated into one processor, or may exist physically separately, or two or more modules may be integrated into one module. The above-mentioned integrated modules may be implemented in the form of hardware or in the form of software functional modules.

[0072] In another embodiment of the present invention, a computer device is provided, the computer device comprising a processor and a memory, the memory being used to store a computer program, the computer program comprising program instructions, and the processor being used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function; the processor described in the embodiment of the present invention can be used for the operation of an evaluation method for tight sandstone condensate gas layers.

[0073] In another embodiment of the present invention, the present invention further provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device for storing programs and data. It is understandable that the computer-readable storage medium here can include both built-in storage media in the computer device and, of course, extended storage media supported by the computer device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the above-mentioned embodiment in a method for evaluating a tight sandstone condensate gas layer.

[0074] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0075] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0076] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0077] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for evaluating tight sandstone condensate gas layers, characterized in that: include: Obtain the C1 peak value of the after-effect gas logging and the C1 peak value of the gas logging during drilling, as well as the broken gas coefficient and gas logging morphological characteristic values ​​during drilling; The after-effect index is constructed based on the relationship between the C1 peak value of the after-effect gas logging and the C1 peak value of the gas logging during drilling; The gas content index is constructed based on the broken gas coefficient during drilling and the gas measurement morphological characteristic value; The after-effect index and gas content index are then combined to establish a two-dimensional condensate gas layer evaluation map for fluid property identification.

2. The evaluation method for tight sandstone condensate gas layer according to claim 1, characterized in that: Acquisition of the post-effect gas test C1 peak value and the gas test C1 peak value during drilling: The after-effect gas measurement C1 value is obtained by real-time collection and analysis by the chromatographic analysis acquisition analyzer in the logging equipment during the after-effect detection, and the maximum value of the after-effect gas measurement C1 value is taken as the after-effect gas measurement C1 peak value; the gas measurement C1 value during drilling is obtained by real-time collection and analysis by the chromatographic analysis analyzer in the logging equipment during the drilling process, and the maximum value of the gas measurement C1 value in the oil and gas display section is taken as the gas measurement C1 peak value during drilling.

3. The evaluation method for tight sandstone condensate gas layer according to claim 1, characterized in that: The crushing gas coefficient and gas measurement morphological characteristic values ​​during drilling: The gas logging C1 value of the surrounding rock before drilling into the reservoir is taken as the base value before gas logging C1, the gas logging C1 value of the bottom plate after drilling through the reservoir is taken as the base value after gas logging C1, and the ratio of the base value before gas logging C1 to the base value after gas logging C1 is taken as the reservoir fragmentation gas coefficient, and its value range is >0 and ≦1. The larger the value, the more obvious the reservoir fragmentation gas characteristics are. The gas logging morphological characteristic value is described by the mean value of gas logging C1 of the reservoir, that is, the average value of the gas logging C1 value of the reservoir section is taken, combined with the change of the base value before and after gas logging C1 of the reservoir, which reflects the morphological characteristics of the reservoir gas logging C1.

4. The evaluation method for tight sandstone condensate gas layer according to claim 1, characterized in that: The after-effect index is constructed based on the relationship between the C1 peak value of the after-effect gas logging and the C1 peak value of the gas logging during drilling: By counting and analyzing the after-effect gas logging C1 peak value and the gas logging C1 peak value during drilling of the condensate gas layer, low gas production layer, gas-water layer, gas-bearing water layer and water layer in the condensate gas layer block, the relationship between the after-effect gas logging C1 peak value and the gas logging C1 peak value during drilling and the empirical value of the boundary of the after-effect gas logging C1 peak value of the condensate gas layer, gas-water layer, low gas production layer, gas-bearing water layer and water layer are obtained. These relationships are quantified and calculated to obtain the after-effect index HXf, and the calculation formula is Hxf=(HXC1 / ZJC1)*(HXC1 / 20%); when there is no obvious change in the drilling fluid density during drilling and after-effect measurement, the larger the after-effect index is, the higher the probability of obtaining a valuable layer.

5. The evaluation method for tight sandstone condensate gas layer according to claim 1, characterized in that: The gas content index constructed based on the broken gas coefficient during drilling and the gas measurement morphological characteristic value: The reservoir gas testing C1 pre-base value QJC1, gas testing C1 post-base value HJC1, and gas testing C1 average value JZC1 are quantified and calculated to obtain the reservoir gas content index HQf. The calculation formula is HQf=JZC1*(QJC1 / HJC1). The larger the reservoir gas content index, the higher the probability of obtaining a valuable layer.

6. The evaluation method for tight sandstone condensate gas layer according to claim 1, characterized in that: The after-effect index and gas content index are combined to establish a two-dimensional condensate gas layer evaluation map: With the after-effect index as the horizontal axis and the gas content index as the vertical axis, the two are intersected, and the valuable layer area and non-valuable area are divided according to the mathematical statistics of the sample points to form a condensate gas layer evaluation map.

7. An evaluation system for tight sandstone condensate gas layers, characterized in that: include: The data acquisition module is used to obtain the C1 peak value of the after-effect gas logging and the C1 peak value of the gas logging during drilling, as well as the broken gas coefficient and gas logging morphological characteristic value during drilling; The after-effect index construction module is used to construct the after-effect index based on the relationship between the C1 peak value of the after-effect gas logging and the C1 peak value of the gas logging during drilling; Gas index construction module, used to construct the gas index based on the broken gas coefficient and gas measurement morphological characteristic values ​​during drilling; The evaluation map construction module is used to intersect the after-effect index and the gas content index to establish a two-dimensional condensate gas layer evaluation map for fluid property identification.

8. The evaluation system for tight sandstone condensate gas layers according to claim 8, characterized in that: Acquisition of the post-effect gas test C1 peak value and the gas test C1 peak value during drilling: The after-effect gas test C1 value is obtained by real-time collection and analysis by the chromatographic analysis acquisition analyzer in the logging equipment during the after-effect detection, and the maximum value of the after-effect gas test C1 value is taken as the after-effect gas test C1 peak value; the gas test C1 value during drilling is obtained by real-time collection and analysis by the chromatographic analyzer in the logging equipment during the drilling process, and the maximum value of the gas test C1 value in the oil and gas display section is taken as the gas test C1 peak value during drilling; The after-effect index is constructed based on the relationship between the C1 peak value of the after-effect gas logging and the C1 peak value of the gas logging during drilling: By counting and analyzing the C1 peak values ​​of the after-effect gas logging of the condensate gas layer, low gas production layer, gas-water layer, gas-bearing water layer, and water layer in the condensate gas layer block, and the C1 peak values ​​of the gas logging during drilling, the relationship between the C1 peak values ​​of the after-effect gas logging of the condensate gas layer, gas-water layer, low gas production layer, gas-bearing water layer, and water layer and the C1 peak values ​​of the gas logging during drilling, and the empirical value of the boundary of the C1 peak values ​​of the after-effect gas logging, these relationships are quantitatively calculated to obtain the after-effect index HXf, and the calculation formula is Hxf = (HXC1 / ZJC1) * (HXC1 / 20%); when there is no obvious change in the density of the drilling fluid during drilling and after-effect measurement, the larger the after-effect index, the higher the probability of obtaining a valuable layer; The gas content index constructed based on the broken gas coefficient during drilling and the gas measurement morphological characteristic value: The reservoir gas testing C1 pre-base value QJC1, gas testing C1 post-base value HJC1, and gas testing C1 average value JZC1 are quantified and calculated to obtain the reservoir gas content index HQf. The calculation formula is HQf=JZC1*(QJC1 / HJC1). The larger the reservoir gas content index, the higher the probability of obtaining a valuable layer.

9. A computer device comprising 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, the steps of the evaluation method for tight sandstone condensate gas layers as described in any one of claims 1 to 6 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the evaluation method for tight sandstone condensate gas layers as claimed in any one of claims 1 to 6 are implemented.

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