A method and apparatus for evaluating the gas content of shale.

Abstract

This invention discloses a method and apparatus for evaluating the gas-bearing capacity of shale. The method includes: establishing the relationship between the shale thickness and the gas-bearing layer thickness in the target stratum of the study area, and then establishing a scoring standard for gas-bearing layer thickness development; determining the gas-bearing thickness score of the well based on the shale thickness or gas-bearing layer thickness; establishing a gas-bearing capacity scoring standard based on the total gas content obtained from core testing data and the lower limit standard for industrial gas flow of shale gas, and determining the gas-bearing capacity score based on the total gas content; obtaining compressibility parameters from elastic wave velocity logging curves, establishing the relationship between compressibility parameters and reservoir stimulation volume, and then establishing an engineering parameter scoring standard; determining the engineering score of the well based on the compressibility parameters; and determining a comprehensive geological and engineering score based on the gas-bearing capacity score, gas-bearing capacity score, and engineering score. This method comprehensively considers geological and engineering factors to provide a reasonable and quantitative evaluation of shale gas-bearing capacity, providing reference data for predicting favorable shale gas areas.

Description

Technical Field

[0001] This invention relates to the field of shale gas exploration and development technology, and in particular to a method and apparatus for evaluating the gas content of shale. Background Technology

[0002] The success of shale gas exploration and development in North America has sparked a global boom in unconventional oil and gas exploration and development. Unconventional oil and gas, as a replacement energy source for conventional oil and gas, plays a crucial role. Currently, my country's dependence on imported oil and gas has exceeded the warning line, and the domestic oil and gas exploration and development situation is severe and the tasks are arduous. In recent years, with the continuous increase in shale gas exploration efforts and the improvement of large-scale fracturing technology, shale gas has achieved commercial exploitation in some areas. However, there is still a lack of standardized methods for predicting favorable shale gas areas. Conducting geological and engineering "sweet spots" predictions for shale gas and identifying favorable shale gas areas are fundamental to achieving commercial shale gas exploitation. Summary of the Invention

[0003] The inventors discovered that most current methods for predicting shale gas "sweet spots" only consider single factors such as geological or engineering factors. Furthermore, when considering geological factors, they only consider the single parameter of gas content, while ignoring macroscopic factors such as the thickness of gas-bearing layers that affect the total gas content. This results in a discrepancy between the predicted favorable shale gas areas and the actual development situation, leading to a double waste of resources and the economy.

[0004] In order to at least partially solve the technical problems existing in the prior art, the inventors made this invention, which, through specific implementation methods, provides a method and apparatus for evaluating the gas content of shale, which can comprehensively consider multiple geological and engineering factors, reasonably evaluate the gas content of shale, and realize reasonable prediction of favorable shale gas areas.

[0005] In a first aspect, embodiments of the present invention provide a method for evaluating the gas content of shale, comprising:

[0006] Determine the shale thickness and gas-bearing layer thickness of wells in the target stratum within the study area, establish a first relationship between shale thickness and gas-bearing layer thickness, establish a gas-bearing layer thickness development scoring standard based on the first relationship, and determine the gas-bearing thickness score of the well based on the gas-bearing layer thickness development scoring standard and the shale thickness or gas-bearing layer thickness of the well.

[0007] A gas content scoring standard is established based on the total gas content obtained from the core test data of the well in the target stratum and the lower limit standard of industrial gas flow of shale gas. The gas content score of the well is determined based on the gas content scoring standard and the total gas content of the corresponding core of the well.

[0008] By using elastic wave velocity logging curves, the compressibility parameters of the well in the target formation are obtained. The compressibility parameters are determined based on the brittleness index and the difference between the maximum and minimum horizontal principal stresses. A second relationship between the compressibility parameters and the reservoir stimulation volume is established. An engineering parameter scoring standard is established based on the second relationship. The engineering score of the well is determined based on the engineering parameter scoring standard and the compressibility parameters of the well.

[0009] The comprehensive geological engineering score is determined based on the well's gas-bearing thickness score, gas content score, and engineering score.

[0010] Secondly, embodiments of the present invention provide a shale gas content evaluation device, comprising:

[0011] The gas-bearing thickness score determination module is used to determine the shale thickness and gas-bearing layer thickness of wells in the target stratum within the study area, establish a first relationship between shale thickness and gas-bearing layer thickness, establish a gas-bearing layer thickness development scoring standard based on the first relationship, and determine the gas-bearing thickness score of the well based on the gas-bearing layer thickness development scoring standard and the shale thickness or gas-bearing layer thickness of the well.

[0012] The gas content score determination module is used to establish a gas content scoring standard by using the total gas content obtained from the core test data of the well in the target layer and the lower limit standard of shale gas industrial gas flow. Based on the gas content scoring standard and the total gas content of the corresponding core of the well, the gas content score of the well is determined.

[0013] The engineering score determination module is used to obtain the compressibility parameters of the well in the target formation through the elastic wave velocity logging curve. The compressibility parameters are determined based on the brittleness index and the difference between the maximum and minimum horizontal principal stresses. A second relationship between the compressibility parameters and the reservoir stimulation volume is established. An engineering parameter scoring standard is established based on the second relationship. The engineering score of the well is determined based on the engineering parameter scoring standard and the compressibility parameters of the well.

[0014] The Geological Engineering Comprehensive Score Determination Module is used to determine the comprehensive score of geological engineering based on the well's gas-bearing thickness score, gas content score, and engineering score.

[0015] Thirdly, embodiments of the present invention provide a computer program product, including a computer program / instruction, wherein the computer program / instruction, when executed by a processor, implements the above-mentioned shale gas content evaluation method.

[0016] Fourthly, embodiments of the present invention provide a server, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the above-described shale gas content evaluation method.

[0017] The beneficial effects of the above-described technical solutions provided in the embodiments of the present invention include at least the following:

[0018] (1) The shale gas content evaluation method provided in this embodiment of the invention comprehensively considers geological factors (gas layer thickness and gas content) and engineering factors to make a reasonable quantitative evaluation of shale gas content and provide reference data for the prediction of favorable shale gas areas.

[0019] (2) The shale gas content evaluation method provided in this embodiment of the invention comprehensively considers the geological factors that affect shale gas enrichment and the engineering parameters that are conducive to shale gas development. The predicted shale gas favorable areas not only meet the requirements for shale gas enrichment but also meet the conditions for shale gas development and construction. It is highly operable and feasible.

[0020] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0023] Figure 1 This is a flowchart of the shale gas content evaluation method in Embodiment 1 of the present invention;

[0024] Figure 2 This is a flowchart illustrating the specific implementation of determining the compressibility parameters in Embodiment 1 of the present invention.

[0025] Figure 3 This is a schematic diagram of the superimposed method for evaluating the gas content of shale considering multiple factors in Embodiment 1 of the present invention;

[0026] Figure 4 This is a flowchart illustrating the specific implementation of the shale gas content evaluation method in Embodiment 2 of the present invention;

[0027] Figure 5 This is a graph showing the relationship between shale thickness and gas-bearing layer thickness in Embodiment 2 of the present invention;

[0028] Figure 6 This is a planar distribution diagram of the shale gas-bearing thickness evaluation results in Embodiment 2 of the present invention;

[0029] Figure 7 This is a planar distribution diagram of the shale gas content evaluation results in Embodiment 2 of the present invention;

[0030] Figure 8This is a planar distribution diagram of the evaluation results of engineering factors for shale gas-bearing in Embodiment 2 of the present invention;

[0031] Figure 9 This is a planar distribution map of the comprehensive evaluation results of shale gas-bearing geological engineering in Embodiment 2 of the present invention;

[0032] Figure 10 This is a schematic diagram of the shale gas content evaluation device in an embodiment of the present invention. Detailed Implementation

[0033] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0034] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0035] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0036] To address the problem that existing technologies for predicting shale gas "sweet spots" cannot comprehensively consider multiple factors, this invention provides a method and apparatus for evaluating shale gas content, which comprehensively considers geological and engineering factors to provide a reasonable quantitative evaluation of shale gas content.

[0037] Example 1

[0038] Embodiment 1 of the present invention provides a method for evaluating the gas content of shale, the process of which is as follows: Figure 1 As shown, it includes the following steps:

[0039] Step S11: Determine the shale thickness and gas-bearing layer thickness of the well in the target stratum within the study area, establish the first relationship between shale thickness and gas-bearing layer thickness, establish a gas-bearing layer thickness development scoring standard based on the first relationship, and determine the gas-bearing thickness score of the well based on the gas-bearing layer thickness development scoring standard and the shale thickness or gas-bearing layer thickness of the well.

[0040] Identify the logging curve characteristics of the gas-bearing sections (i.e., gas-bearing sections);

[0041] All wells in the shale gas research area were re-examined, and the thickness of the gas-bearing layer in the target section of each well was determined by the characteristics of the logging curves of the gas-bearing layer and the gas logging data.

[0042] Similarly, determine the shale (including mudstone and shale) thickness in the target stratum for each well;

[0043] Establish the relationship between shale thickness and gas-bearing layer thickness, determine the macroscopic controlling factors of gas-bearing layer thickness, and establish a scoring standard for gas-bearing layer thickness development.

[0044] It could be to establish a scoring standard for the development of gas-bearing layer thickness based on shale thickness, or it could be to establish a scoring standard for the development of gas-bearing layer thickness based on gas-bearing layer thickness.

[0045] The gas-bearing thickness score of the well is determined based on the gas-bearing layer thickness development scoring standard and the shale thickness of the well; or, the gas-bearing thickness score of the well is determined based on the gas-bearing layer thickness development scoring standard and the gas-bearing layer thickness of the well.

[0046] Step S12: Establish a gas content scoring standard by using the total gas content obtained from the core test data of the well in the target layer and the lower limit standard of industrial gas flow of shale gas. Determine the gas content score of the well based on the gas content scoring standard and the total gas content of the corresponding core.

[0047] Determining the total gas content of the core may include: determining multiple different temperatures based on the shale gas extraction pattern from the core and the formation temperature change pattern during the core lifting process; conducting in-situ analysis experiments at different temperatures using a multi-stage heating method to obtain the in-situ extracted gas content of the core; selecting methods for recovering lost gas based on the different extraction temperature curves of the core to determine the lost gas content of the core; and adding the extracted gas content and the lost gas content of the core to obtain the total gas content under in-situ conditions.

[0048] Specifically, the screening of methods for recovering lost gas volume can include selecting any method suitable for the characteristics of different analytical temperature curves of the core from linear back extrapolation, formula fitting, and process analysis methods for recovering lost gas volume.

[0049] Step S13: Obtain the compressibility parameters of the well in the target formation through the elastic wave velocity logging curve, establish a second relationship between the compressibility parameters and the reservoir stimulation volume, establish an engineering parameter scoring standard based on the second relationship, and determine the engineering score of the well based on the engineering parameter scoring standard and the compressibility parameters of the well.

[0050] The compressibility parameters are determined based on the brittleness index and the difference between the maximum and minimum horizontal principal stresses. (Refer to...) Figure 2 As shown, the compressibility parameters of the well in the target formation can be determined through the following steps:

[0051] Step S21: Obtain the brittleness index and the distribution data of the maximum and minimum principal stress difference in the target layer of the well through the elastic wave velocity logging curve.

[0052] The elastic modulus and Poisson's ratio distribution data of the well in the target layer are calculated using the elastic wave velocity logging curve; based on the normalized elastic modulus distribution data and the normalized Poisson's ratio distribution data, the brittleness index distribution data is determined by weighted averaging.

[0053] The brittleness index characterizes the mechanical properties of rocks in in-situ underground environments.

[0054] By using the elastic wave velocity logging curves, the distribution data of the maximum and minimum horizontal principal stresses in the target layer are calculated using the Huang's model method, and then the distribution data of the difference between the maximum and minimum horizontal principal stresses are determined.

[0055] Step S22: Based on the normalized brittleness index distribution data, determine the brittleness index of the well in the target layer; based on the normalized distribution data of the maximum and minimum horizontal principal stress difference, determine the maximum and minimum horizontal principal stress difference of the well in the target layer.

[0056] The brittleness index is a positive indicator of gas-bearing favorable areas, and its distribution data can be normalized using the following formula:

[0057]

[0058] Among them, B and B n B represents the brittleness index value and the normalized post-brittleness index of a data point in the brittleness index distribution data, respectively. max and B min These represent the maximum and minimum brittleness index values ​​in the brittleness index distribution data, respectively.

[0059] The difference between the maximum and minimum horizontal principal stresses is an inverse indicator of the favorable gas-bearing area. The normalization of its distribution data can be achieved using the following formula:

[0060]

[0061] Where σ and σn These represent the maximum and minimum horizontal principal stress differences at a given data point in the distribution data of the maximum and minimum horizontal principal stress differences, respectively, and the normalized maximum and minimum horizontal principal stress differences, σ. max and σ min These represent the maximum and minimum values ​​in the distribution data of the maximum and minimum principal stress differences at the horizontal level.

[0062] The brittleness index of the target layer can be determined by the average of the normalized brittleness index of each data point in the target layer; the difference between the maximum and minimum horizontal principal stresses of the target layer can be determined by the average of the normalized difference between the maximum and minimum horizontal principal stresses of each data point in the target layer.

[0063] Step S23: Based on the brittleness index and the difference between the maximum and minimum principal stresses at the horizontal level in the target formation, determine the compressibility parameters of the well in the target formation using a weighted average method.

[0064] For example, the compressibility parameter F can be determined using the following formula. n :

[0065]

[0066] Step S14: Determine the comprehensive geological engineering score based on the well's gas-bearing thickness score, gas content score, and engineering score.

[0067] The overall score for geological engineering can be determined using the following formula:

[0068] ω=ω1α+ω2β+ω3γ

[0069] Where ω represents the comprehensive score for geological engineering, ω1, ω2, and ω3 represent the scores for gas-bearing thickness, gas content, and engineering, respectively, and α, β, and γ represent the weighting coefficients for these scores. The strength of the correlation between each parameter and gas production is determined based on their linear relationship, and then the weighting coefficients are determined accordingly.

[0070] The shale gas-bearing evaluation method provided in Embodiment 1 of this invention is a comprehensive evaluation method for assessing shale gas-bearing capacity by considering factors affecting shale gas exploration and development, such as shale gas enrichment geological conditions and engineering parameters. It utilizes a comprehensive application of methods based on experimental measurements, model establishment, and well logging to clarify the optimal criteria for key shale gas exploration and development parameters, including gas-bearing layer thickness (or shale thickness), gas content, and engineering parameters (compressibility). The gas-bearing capacity is then evaluated by comprehensively considering these parameters. The underlying approach is described in [reference needed]. Figure 3 As shown, this allows for a comprehensive and quantitative evaluation of shale gas content, taking into account both geological factors (gas-bearing layer thickness and gas content) and engineering factors, thus providing reference data for predicting favorable shale gas areas.

[0071] In some embodiments, the method may further include obtaining the distribution data of the comprehensive geological engineering scores of the target strata in the study area by setting an interpolation method based on the comprehensive geological engineering scores of the wells in the study area.

[0072] In some embodiments, it may also include predicting shale gas favorable zones within the target stratigraphic segment of the study area based on geological engineering comprehensive score distribution data.

[0073] Establish shale gas evaluation standards, which may include intervals of comprehensive scores from various geological engineering projects and corresponding gas-bearing levels. Using these standards, and based on the distribution data of the comprehensive geological engineering scores, classify and evaluate the gas-bearing capacity of shale, and create a grading map of favorable shale gas zones.

[0074] Taking into account both the geological factors affecting shale gas enrichment and the engineering parameters favorable to shale gas development, the predicted favorable shale gas areas not only meet the requirements for shale gas enrichment but also satisfy the conditions for shale gas development and construction. The results are highly operable and feasible.

[0075] Example 2

[0076] Embodiment 2 of the present invention provides a specific implementation flow of a method for evaluating the gas content of shale. Taking the evaluation of the gas content of marine shale in southern my country as an example, the flow is as follows: Figure 4 As shown, it includes the following steps:

[0077] Step S41: Establish a scoring standard for gas-bearing layer thickness development and determine the gas-bearing thickness score of the well.

[0078] The specific implementation method is described in Example 1, and the established relationship between shale thickness and gas-bearing layer thickness is as follows: Figure 5 As shown. Based on the successful exploration and development experience of marine shale gas blocks in southern my country, and considering both the effectiveness and economic feasibility of horizontal well fracturing technology, a shale layer thickness greater than 30m is determined as the lower limit of effective thickness for shale gas development. Given the limited gas logging data, which makes it impossible to obtain the gas layer thickness of each well, a gas-bearing layer thickness development scoring standard is established based on the relationship between shale thickness and gas-bearing layer thickness as follows:

[0079] Category I: Shale layer thickness > 110m, 3 points;

[0080] Category II: 70m < shale layer thickness ≤ 110m, 2 points;

[0081] Class III: 30m < shale layer thickness ≤ 70m, 1 point.

[0082] The planar distribution map of the obtained shale gas-bearing thickness evaluation results is as follows: Figure 6 As shown.

[0083] Step S42: Establish a gas content scoring standard and determine the gas content score of the well.

[0084] The specific implementation method is described in Example 1, and the established gas content scoring standard is as follows:

[0085] Category I: Gas content > 2m 3 / t, 3 points;

[0086] Class II: 1m 3 / t < gas content ≤ 2m 3 / t, 2 points;

[0087] Class III: 0.5m 3 / t<Gas content≤1m 3 / t, 1 point.

[0088] See Figure 7 The figure shows the planar distribution of the obtained shale gas content evaluation results.

[0089] Step S43: Establish engineering parameter scoring criteria and determine the engineering score of the well.

[0090] The specific implementation method is described in Example 1. Based on the principle that higher rock elastic modulus, lower Poisson's ratio, and smaller horizontal stress difference are more conducive to the generation, extension, and expansion of fracture networks, which is beneficial to reservoir fracturing, and combined with practical experience, the following engineering parameter scoring criteria were established:

[0091] Category I: Compressibility index ≥ 0.6, 3 points;

[0092] Category II: 0.3 < compressibility index ≤ 0.6, score 2 points;

[0093] Category III: Compressibility index ≤ 0.3, 1 point.

[0094] See Figure 8 The figure shows the planar distribution of the evaluation results of engineering factors for shale gas-bearing formations.

[0095] Step S44: Determine the comprehensive geological engineering score based on the well's gas-bearing thickness score, gas content score, and engineering score.

[0096] By using the formula ω=ω1α+ω2β+ω3γ, the strength of the correlation between each parameter and the gas production is determined based on the linear relationship between them, and then the weight coefficients are determined to determine the comprehensive score of the geological engineering.

[0097] Step S45: Obtain the geological engineering comprehensive score distribution data of the target stratum in the study area by setting the interpolation method.

[0098] Step S46: Establish evaluation criteria for marine shale gas selection areas and predict favorable shale gas areas within the target stratigraphic interval of the study area.

[0099] The following evaluation criteria are established for marine shale gas selection areas:

[0100] 2.5≤ω≤3 indicates a favorable area for shale gas exploration (Class I).

[0101] 1.5≤ω<2.5, which is a favorable area for shale gas exploration (Class II).

[0102] 1≤ω<1.5, a favorable area for shale gas exploration (Class III).

[0103] See Figure 9 The image shows a planar distribution map of the comprehensive evaluation results of shale gas-bearing geological engineering.

[0104] Based on the inventive concept of this invention, embodiments of this invention also provide a shale gas content evaluation device, the structure of which is as follows: Figure 10 As shown, it includes:

[0105] The gas-bearing thickness score determination module 101 is used to determine the shale thickness and gas-bearing layer thickness of wells in the target stratum within the study area, establish a first relationship between shale thickness and gas-bearing layer thickness, establish a gas-bearing layer thickness development scoring standard based on the first relationship, and determine the gas-bearing thickness score of the well based on the gas-bearing layer thickness development scoring standard and the shale thickness or gas-bearing layer thickness of the well.

[0106] The gas content score determination module 102 is used to establish a gas content scoring standard by using the total gas content obtained from the core test data of the well in the target layer and the lower limit standard of shale gas industrial gas flow, and to determine the gas content score of the well based on the gas content scoring standard and the total gas content of the core corresponding to the well.

[0107] The engineering score determination module 103 is used to obtain the compressibility parameters of the well in the target formation through the elastic wave velocity logging curve. The compressibility parameters are determined based on the brittleness index and the difference between the maximum and minimum horizontal principal stresses. A second relationship between the compressibility parameters and the reservoir stimulation volume is established. An engineering parameter scoring standard is established based on the second relationship. The engineering score of the well is determined based on the engineering parameter scoring standard and the compressibility parameters of the well.

[0108] The geological engineering comprehensive score determination module 104 is used to determine the geological engineering comprehensive score based on the well's gas-bearing thickness score, gas content score, and engineering score.

[0109] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0110] Based on the inventive concept of the present invention, embodiments of the present invention also provide a computer program product, including a computer program / instruction, wherein the computer program / instruction, when executed by a processor, implements the above-mentioned shale gas content evaluation method.

[0111] Based on the inventive concept of the present invention, an embodiment of the present invention also provides a server, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the above-mentioned shale gas content evaluation method.

[0112] Unless otherwise specifically stated, terms such as processing, calculation, operation, determination, display, etc., may refer to the actions and / or processes of one or more processing or computing systems, or similar devices, which represent the manipulation and conversion of data representing physical (e.g., electronic) quantities within the registers or memory of the processing system into other data similarly representing physical quantities within the memory, registers, or other such information storage, transmission, or display devices of the processing system. Information and signals can be represented using any of a variety of different techniques and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips mentioned throughout the above description can be represented by voltage, current, electromagnetic waves, magnetic fields or particles, light fields or particles, or any combination thereof.

[0113] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process may be rearranged without departing from the scope of this disclosure. The appended method claims provide elements of various steps in an exemplary order and are not intended to limit the scope to the specific order or hierarchy described.

[0114] In the detailed description above, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, the invention is presented with fewer features than all of the features in a single disclosed embodiment. Therefore, the appended claims are hereby explicitly incorporated into the detailed description, wherein each claim stands alone as a preferred embodiment of the invention.

[0115] Those skilled in the art will also understand that the various illustrative logic blocks, modules, circuits, and algorithm steps described in conjunction with the embodiments herein can be implemented as electronic hardware, computer software, or a combination thereof. To clearly illustrate the interchangeability between hardware and software, the various illustrative components, blocks, modules, circuits, and steps described above are generally described in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. Those skilled in the art can implement the described functionality in alternative ways for each specific application; however, such implementation decisions should not be construed as departing from the scope of this disclosure.

[0116] The steps of the methods or algorithms described in conjunction with the embodiments herein can be directly embodied in hardware, software modules executed by a processor, or a combination thereof. The software modules can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium well known in the art. An exemplary storage medium is connected to the processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. The ASIC can reside in a user terminal. Alternatively, the processor and storage medium can exist as discrete components in the user terminal.

[0117] For software implementation, the techniques described in this application can be implemented using modules (e.g., procedures, functions, etc.) that perform the functions described in this application. This software code can be stored in memory units and executed by a processor. The memory units can be implemented within the processor or outside the processor; in the latter case, they are communicatively coupled to the processor via various means, as is well known in the art.

[0118] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, the term “comprising” as used in the specification or claims is interpreted in a manner similar to the term “including,” as it is understood when used as a conjunction in the claims. Additionally, the use of any term “or” in the specification of the claims is intended to mean “non-exclusive or.” The terms “first” and “second” are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

Claims

1. A method for evaluating the gas content of shale, characterized in that, include: Determine the shale thickness and gas-bearing layer thickness of wells in the target stratum within the study area, establish a first relationship between shale thickness and gas-bearing layer thickness, establish a gas-bearing layer thickness development scoring standard based on the first relationship, and determine the gas-bearing thickness score of the well based on the gas-bearing layer thickness development scoring standard and the shale thickness or gas-bearing layer thickness of the well. For the core samples from the target formation, based on the analytical characteristics of shale gas extraction from the core and the formation temperature variation during core lifting, multiple different temperatures were determined. Multi-stage temperature-based in-situ analytical experiments were conducted on the core samples at different temperatures, and the gas content was obtained using the drainage method. Based on the different analytical temperature curves of the core samples, methods for recovering lost gas were selected, and the lost gas content of the core samples was determined. The total gas content under in-situ conditions was obtained by adding the extracted gas content to the lost gas content. By obtaining the total gas content and the lower limit standard of industrial gas flow of shale gas, a gas content scoring standard is established. Based on the gas content scoring standard and the total gas content of the core corresponding to the well, the gas content score of the well is determined. The elastic modulus and Poisson's ratio distribution data of the well in the target formation are obtained through elastic wave velocity logging curves. Based on the normalized elastic modulus and Poisson's ratio distribution data, the brittleness index distribution data is determined using a weighted average method. Using the elastic wave velocity logging curves, the maximum and minimum horizontal principal stress distribution data of the well in the target formation are calculated using the Huang's model method, thereby determining the distribution data of the difference between the maximum and minimum horizontal principal stresses. Based on the normalized brittleness index distribution data, the brittleness index of the well in the target formation is determined. Based on the normalized distribution data of the difference between the maximum and minimum horizontal principal stresses, the difference between the maximum and minimum horizontal principal stresses of the well in the target formation is determined. Based on the brittleness index and the difference between the maximum and minimum principal stresses of the well in the target formation, the compressibility parameters of the well in the target formation are determined by a weighted average method; a second relationship between the compressibility parameters and the reservoir stimulation volume is established; an engineering parameter scoring standard is established based on the second relationship; and the engineering score of the well is determined based on the engineering parameter scoring standard and the compressibility parameters of the well. The comprehensive geological engineering score is determined based on the well's gas-bearing thickness score, gas content score, and engineering score.

2. The method as described in claim 1, characterized in that, The method for recovering lost gas volume specifically includes: Choose any method from linear backpropagation, formula fitting, and process analysis loss gas recovery methods.

3. The method as described in claim 1 or 2, characterized in that, Also includes: Based on the comprehensive geological engineering scores of wells in the study area, the distribution data of the comprehensive geological engineering scores of the target strata in the study area are obtained by setting an interpolation method.

4. The method as described in claim 3, characterized in that, Also includes: Based on the comprehensive geological engineering score distribution data, the favorable shale gas zones within the target strata of the study area are predicted.

5. A device for evaluating the gas content of shale, characterized in that, The apparatus is used to perform the shale gas content evaluation method according to claim 1, and the apparatus comprises: The gas-bearing thickness score determination module is used to determine the shale thickness and gas-bearing layer thickness of wells in the target stratum within the study area, establish a first relationship between shale thickness and gas-bearing layer thickness, establish a gas-bearing layer thickness development scoring standard based on the first relationship, and determine the gas-bearing thickness score of the well based on the gas-bearing layer thickness development scoring standard and the shale thickness or gas-bearing layer thickness of the well. The gas content score determination module is used to establish a gas content scoring standard by using the total gas content obtained from the core test data of the well in the target layer and the lower limit standard of shale gas industrial gas flow. Based on the gas content scoring standard and the total gas content of the corresponding core of the well, the gas content score of the well is determined. The engineering score determination module is used to obtain the compressibility parameters of the well in the target formation through the elastic wave velocity logging curve. The compressibility parameters are determined based on the brittleness index and the difference between the maximum and minimum horizontal principal stresses. A second relationship between the compressibility parameters and the reservoir stimulation volume is established. An engineering parameter scoring standard is established based on the second relationship. The engineering score of the well is determined based on the engineering parameter scoring standard and the compressibility parameters of the well. The Geological Engineering Comprehensive Score Determination Module is used to determine the comprehensive score of geological engineering based on the well's gas-bearing thickness score, gas content score, and engineering score.

6. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instruction is executed by the processor, it implements the shale gas content evaluation method according to any one of claims 1 to 4.

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