Method and device for comprehensive evaluation of tight gas reservoir and favorable area optimization

Abstract

The invention discloses a tight gas reservoir comprehensive evaluation and favorable area optimization method and device, and relates to the technical field of natural gas development, and the tight gas reservoir comprehensive evaluation and favorable area optimization method comprises the following steps: S1, optimizing a reservoir evaluation index parameter system, and determining an index parameter set; s2, determining a research area well set, and constructing an index parameter evaluation matrix; s3, normalizing an index parameter evaluation matrix; s4, determining the weights of the index parameters, and obtaining the entropy weight of each index parameter; s5, solving a reservoir evaluation comprehensive index, and calculating a gas well comprehensive score; s6, performing quantitative division on the comprehensive score of the gas well, and determining a reservoir quantitative evaluation standard; and S7, according to a reservoir quantitative evaluation standard, drawing a reservoir type plane distribution diagram of the research area, and preferably selecting a favorable development area. According to the method, the reservoir can be rapidly and comprehensively evaluated, the reservoir type plane distribution characteristics of different layers of the research area are drawn, the favorable area is preferably selected, and a scientific basis is provided for gas well deployment and efficient development of a gas field.

Description

Technical Field

[0001] The present invention relates to the technical field of natural gas development, and in particular to a method and device for comprehensive evaluation of tight gas reservoirs and optimization of favorable areas. Background Art

[0002] Tight sandstone reservoirs are characterized by low porosity, low permeability, low gas saturation, and poor gas continuity. Different reservoir types contribute significantly to gas production. Rapid and accurate evaluation and classification of tight sandstone reservoirs is crucial for optimizing enrichment zones and ensuring gas field productivity.

[0003] Currently, the main method for comprehensive evaluation of tight sandstone reservoirs is to perform correlation analysis on parameters such as porosity, permeability, gas saturation, and gas layer thickness with production characteristic parameters of gas wells, such as open-flow rate and first-year daily production, and select parameters with good correlation to evaluate the reservoir. However, selecting parameters one by one for correlation analysis greatly increases the workload and is not fully applicable to different blocks, resulting in low efficiency. In addition, the poor correlation of a single reservoir parameter ignores the impact of other factors on the reservoir, resulting in large deviations in reservoir evaluation, failing to fully reflect the reservoir characteristics, and easily leading to erroneous conclusions. Therefore, there is an urgent need for a method and device that can comprehensively and efficiently evaluate tight gas reservoirs and select favorable areas. Summary of the Invention

[0004] The present invention aims to provide a method and apparatus for comprehensive evaluation of tight gas reservoirs and optimization of favorable zones. This approach addresses the problems of tight sandstone reservoirs, which are characterized by low porosity, low permeability, low gas saturation, and poor gas continuity, as well as the significant differences in gas production contributions between different reservoir types. The present invention's rapid and accurate evaluation and classification of tight sandstone reservoirs is of great significance for optimizing enrichment zones and ensuring stable gas field production. To achieve the above objectives, the present invention provides the following technical solutions:

[0005] The present invention provides a method for comprehensive evaluation of tight gas reservoirs and optimization of favorable areas, the method comprising:

[0006] Step S1, optimizing a reservoir evaluation index parameter system and determining a set of index parameters;

[0007] Step S2: determine the well set in the study area and construct an indicator parameter evaluation matrix;

[0008] Step S3, normalizing the index parameter evaluation matrix;

[0009] Step S4: Determine the weight of the indicator parameters using the entropy weight method to obtain the entropy weight of each indicator parameter;

[0010] Step S5: obtaining a comprehensive reservoir evaluation index based on the entropy weight of the index parameters and the normalized matrix, and calculating a comprehensive score of the gas well;

[0011] Step S6: quantitatively classify the comprehensive scores of the gas wells and determine the quantitative evaluation standard of the reservoir;

[0012] Step S7: Draw a planar distribution map of reservoir types in the study area based on the reservoir quantitative evaluation criteria, and select favorable areas for development.

[0013] Furthermore, the index parameters include: porosity, permeability, gas saturation, gas layer thickness, formation coefficient, reservoir coefficient, permeability variation coefficient and breakthrough coefficient.

[0014] Furthermore, the step S2, determining the well set in the study area and constructing the index parameter evaluation matrix, includes:

[0015] Based on the principle of covering the entire study area, the exploration wells, appraisal wells and development wells in the study area are screened, and wells that can obtain logging data and gas production data are selected;

[0016] For n wells and l reservoirs in the selected study area, the reservoir set to be evaluated is determined, which is denoted as: R = (R1, R2, ..., R l );

[0017] Combined with the set of index parameters F=(F1,F2,…,F m ), construct the index evaluation matrix A of m parameters in the study area:

[0018]

[0019] Furthermore, the step S3, normalizing the index parameter evaluation matrix, includes:

[0020] Step S31: unifying the dimensions of index parameters in different units; including:

[0021] 1) For positive index parameters, including porosity, permeability, gas saturation, gas layer thickness, formation coefficient and reservoir coefficient, the following formula is used for normalization:

[0022]

[0023] 2) For negative indicator parameters, including permeability variation coefficient and breakthrough coefficient, the following formula is used for normalization:

[0024]

[0025] Step S32: The matrix after normalization processing is:

[0026]

[0027] Furthermore, the step S4, determining the weight of the indicator parameters using the entropy weight method to obtain the entropy weight of each indicator parameter, includes:

[0028] Step S41: Calculate the entropy value of each indicator parameter and use the entropy value to determine the weight of each indicator parameter in the evaluation process; including:

[0029] 1) The calculation formula of the entropy value of the jth indicator parameter is:

[0030]

[0031] in:

[0032] k=1 / ln l;

[0033]

[0034] When f ij = 0, let f ij ln f ij =0.

[0035] 2) Calculate the weight of the j-th indicator parameter based on the entropy value of the j-th indicator parameter:

[0036]

[0037] in:

[0038] w j ∈[0,1];

[0039]

[0040] Step S42: Use this method to obtain the weight of each indicator parameter to obtain the entropy weight corresponding to each indicator parameter:

[0041] W=w1,w2,…,w m .

[0042] Furthermore, the step S5, obtaining a comprehensive reservoir evaluation index based on the entropy weight of the indicator parameters and the normalized matrix, and calculating a comprehensive score of the gas well, includes:

[0043] Entropy weight w based on indicator parameters j and the normalized matrix B to calculate the comprehensive evaluation index of each reservoir in the study area;

[0044] The evaluation comprehensive index of different reservoir index parameters is summed to obtain the evaluation index of each reservoir:

[0045] For multiple reservoirs in the same well, the evaluation indexes of the multiple reservoirs are weighted averaged according to the thickness of the gas layers to obtain the comprehensive score of the gas well.

[0046] Furthermore, the step S6 of quantitatively classifying the comprehensive scores of the gas wells and determining the quantitative evaluation criteria for the reservoirs includes:

[0047] Draw a cumulative frequency curve of the gas well comprehensive score;

[0048] The comprehensive scores of gas wells in the same type of reservoir have similar slopes on the cumulative frequency curve. The boundaries of reservoir quantitative evaluation are determined based on the comprehensive scores of gas wells corresponding to the intersection points a, b, and c of different slopes.

[0049] The comprehensive score of gas wells in Class I reservoirs is ≥ c;

[0050] Comprehensive scores of gas wells in Class II reservoirs are b to c;

[0051] Comprehensive scores of gas wells in Class III reservoirs are a to b;

[0052] Comprehensive score of gas wells in Class IV reservoirs <a。

[0053] Furthermore, the step S7, drawing a planar distribution map of reservoir types in the study area according to the reservoir quantitative evaluation standard and selecting favorable areas for development, includes:

[0054] Draw contour maps of the comprehensive scores of gas wells, divide the reservoirs on the plane according to the quantitative evaluation standards of reservoirs, and delineate the range of each type of reservoir. Select Class I + II reservoirs as favorable areas, and guide the deployment of development wells based on the current status of the well network and the utilization of reserves.

[0055] The present invention also provides a device for comprehensive evaluation of tight gas reservoirs and optimization of favorable areas, the device comprising:

[0056] A determination module is used to optimize the reservoir evaluation index parameter system and determine the set of index parameters;

[0057] Construction module, used to determine the well set in the study area and construct the indicator parameter evaluation matrix;

[0058] Normalization module, used for normalization of indicator parameter evaluation matrix;

[0059] The acquisition module is used to determine the weight of the indicator parameters using the entropy weight method to obtain the entropy weight of each indicator parameter;

[0060] The calculation module is used to obtain the comprehensive index of reservoir evaluation based on the entropy weight of the indicator parameters and the normalized matrix, and calculate the comprehensive score of the gas well;

[0061] Quantitative classification module, used to quantitatively classify the comprehensive scores of gas wells and determine the quantitative evaluation standards of reservoirs;

[0062] The optimization module is used to draw a planar distribution map of reservoir types in the study area based on the quantitative reservoir evaluation standards and to select favorable development areas.

[0063] Technical effects and advantages of the present invention:

[0064] 1. The present invention processes and analyzes existing gas well logging, production and other data, selects multiple main parameters that can reflect reservoir characteristics, and uses the entropy weight method to obtain a comprehensive evaluation index of the reservoir in the study area and a comprehensive score of the gas wells. It quickly and comprehensively evaluates the reservoir, plots the planar distribution characteristics of reservoir types in different layers of the study area, selects favorable areas, and provides a scientific basis for gas well deployment and ensuring efficient development of gas fields.

[0065] 2. Based on scientific research theories, the present invention is a relatively fast and comprehensive method and device for comprehensive evaluation of tight gas reservoirs and optimization of favorable areas. It provides technical support for the reserve classification evaluation and sustainable and profitable development of gas fields. The analysis conclusions are relatively accurate and the overall implementation effect is obvious.

[0066] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0068] Figure 1 This is a flow chart of a method for comprehensive evaluation of tight gas reservoirs and optimization of favorable areas according to the present invention;

[0069] Figure 2 This is a cumulative frequency curve of the comprehensive scores of gas wells in a certain block of the ancient gas reservoir in the Jingbian gas field according to an embodiment of the present invention;

[0070] Figure 3 This is a planar distribution diagram of reservoir types in a block of the ancient gas reservoir in the Jingbian gas field according to an embodiment of the present invention;

[0071] Figure 4 This is a schematic diagram of a device for comprehensive evaluation of tight gas reservoirs and optimization of favorable areas according to the present invention. DETAILED DESCRIPTION

[0072] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0073] In order to solve the deficiencies of the prior art, the present invention discloses a method for comprehensive evaluation of tight gas reservoirs and optimization of favorable areas. Figure 1 The flowchart of the method for comprehensive evaluation of tight gas reservoirs and optimization of favorable areas of the present invention is as follows: Figure 1 As shown, the method includes:

[0074] Step S1: Optimize the reservoir evaluation index parameter system and determine the set of index parameters.

[0075] Eight parameters, including porosity, permeability, gas saturation, gas layer thickness, formation coefficient, reservoir coefficient, permeability variation coefficient and breakthrough coefficient, are selected as the main parameters for reservoir evaluation to conduct a comprehensive evaluation of the reservoir.

[0076] Preferably, the gas layer thickness (H), porosity Permeability (K), gas saturation (S gi ) The four parameters are obtained through the logging data of the target gas well.

[0077] Preferably, the formation coefficient (F i ) is obtained by the following method:

[0078] F i =K i ×H i ;

[0079] Where, F i is the formation coefficient of the i-th reservoir, mD·m; K i is the permeability of the i-th reservoir, mD; H i is the gas layer thickness of the i-th reservoir, m.

[0080] Preferably, the reservoir coefficient (R i ) is obtained by the following method:

[0081]

[0082] Where R i is the reservoir coefficient of the i-th reservoir; H i is the gas layer thickness of the i-th reservoir, m; is the porosity of the i-th reservoir layer, %; Sgi is the gas saturation of the i-th reservoir, %.

[0083] Preferably, the permeability variation coefficient (K v ) is obtained by the following method:

[0084]

[0085] Where K v is the permeability variation coefficient, dimensionless; K i is the permeability of the i-th reservoir, mD; is the average permeability of the reservoir, mD; n is the number of samples in the layer.

[0086] Preferably, the thrust coefficient (T k ) is obtained by the following method:

[0087]

[0088] Where, T k is the thrust coefficient, dimensionless; K max is the maximum value of reservoir permeability, mD; K is the permeability of the reservoir, mD.

[0089] The set of various index parameters is recorded as: F=(F1, F2,…, F m ).

[0090] Step S2: Determine the well set in the study area and construct an indicator parameter evaluation matrix.

[0091] Based on the principle of covering the entire study area as much as possible, the exploration wells, evaluation wells, and development wells in the study area are screened, and wells that can obtain logging data and gas production data are selected to ensure a full understanding of the geology of the study area. For n wells and l reservoirs in the selected study area, the reservoir set to be evaluated is determined, which is recorded as: R = (R1, R2, ..., R l ). Combined with the set of indicator parameters F=(F1,F2,…,F m ), construct the index evaluation matrix A of m parameters in the study area:

[0092]

[0093] Step S3: Normalize the index parameter evaluation matrix.

[0094] Unify the dimensions of the indicator parameters of different units to obtain the normalized evaluation matrix B. This is processed in the following way:

[0095] 1) For positive index parameters (the higher the parameter value, the better the reservoir quality) such as porosity, permeability, gas saturation, gas layer thickness, formation coefficient and reservoir coefficient, the following formula is used for normalization.

[0096]

[0097] 2) For negative indicator parameters (the higher the parameter value, the worse the reservoir quality), such as permeability variation coefficient and surge coefficient, the following formula is used for normalization.

[0098]

[0099] The matrix after normalization is:

[0100]

[0101] Step S4: Determine the weights of the indicator parameters using the entropy weight method to obtain the entropy weight corresponding to each indicator parameter.

[0102] Calculate the entropy value of each indicator parameter and use the entropy value to determine the weight of each indicator in the evaluation process.

[0103] 1) The calculation formula of the entropy value of the jth indicator parameter is:

[0104]

[0105] in:

[0106] C = 1 / ln l;

[0107]

[0108] Where, E j is the entropy value of the jth indicator parameter, k is a constant, f ij is the numerical weight of the jth indicator of the i-th project, l is the number of rows in the matrix, b ij is the value of the jth indicator of the i-th item in the matrix B after normalization (i=1, 2, ..., l; j=1, 2, ..., m).

[0109] When f ij = 0, let f ij ln f ij =0.

[0110] 2) According to the entropy value of the j-th indicator parameter, calculate the entropy weight of the j-th indicator parameter:

[0111]

[0112] in:

[0113] wj ∈[0,1];

[0114]

[0115] Where w j is the entropy weight of the jth indicator parameter, E j is the entropy value of the jth indicator parameter, and m is the number of columns in the matrix.

[0116] This method is used to obtain the weight of each indicator parameter and obtain the entropy weight corresponding to each indicator parameter:

[0117] W=w1,w2,…,w m .

[0118] Step S5: Obtain a comprehensive reservoir evaluation index and calculate a comprehensive score for the gas well.

[0119] Entropy weight w based on indicator parameters j The evaluation comprehensive index of each reservoir in the study area is calculated by using the normalized matrix B, and the quality of each reservoir is analyzed. ij Obtained by the following formula:

[0120] I ij =W B ;

[0121] The evaluation comprehensive index of the eight types of index parameters of different reservoirs is summed up to obtain the evaluation index of each reservoir. The evaluation index G of the i-th reservoir is si Obtained by the following formula:

[0122]

[0123] in:

[0124] I ij ∈(0,1);

[0125]

[0126] For multiple reservoirs in the same well, the evaluation index G of multiple reservoirs is calculated based on the thickness of the gas layer. si Perform weighted averaging to obtain the comprehensive score of the gas well, and the comprehensive score of the qth reservoir is G tq Obtained by the following formula:

[0127]

[0128] in:

[0129] k∈[1,l];

[0130] q∈[1,n];

[0131] Where H i is the gas layer thickness of the i-th reservoir, m, l are the number of rows in the matrix, k is the k-th row in the matrix, n is the number of reservoir sets, and q is the q-th reservoir set.

[0132] Step S6: quantitatively classify the comprehensive scores of the gas wells to determine the quantitative evaluation criteria for the reservoir.

[0133] Draw a cumulative frequency curve of the comprehensive score of the gas wells. The comprehensive scores of gas wells in the same type of reservoir have similar slopes on the cumulative frequency curve. According to the comprehensive scores of gas wells corresponding to the intersection points a, b, and c of different slopes, the boundaries of reservoir quantitative evaluation are determined. The comprehensive score of gas wells in type I reservoirs is ≥ c, the comprehensive score of gas wells in type II reservoirs is b~c, the comprehensive score of gas wells in type III reservoirs is a~b, and the comprehensive score of gas wells in type IV reservoirs is <a。

[0134] Similarly, using the reservoir evaluation index G of each reservoir s By dividing the quantitative evaluation criteria by the cumulative frequency curve method, the reservoir type can be divided for a single reservoir. For the reservoir characteristics of multi-layer superposition of tight gas reservoirs, the comprehensive score G of gas wells is used. t The classification of multi-layer superimposed reservoirs is more instructive for the well location deployment and production capacity construction of the entire tight gas reservoir.

[0135] Step S7: Draw a planar distribution map of reservoir types in the study area based on the reservoir quantitative evaluation criteria, and select favorable areas for development.

[0136] Draw contour maps of the comprehensive scores of gas wells, divide the reservoirs on the plane according to the quantitative evaluation standards of reservoirs, and delineate the range of each type of reservoir. Select Class I + II reservoirs as favorable areas, and guide the deployment of development wells based on the current status of the well network and the utilization of reserves.

[0137] Example:

[0138] A block in the ancient Jingbian gas field is a typical tight sandstone gas field characterized by low porosity and permeability. Through long-term development, a wealth of geological and production data has been accumulated. To ensure sustained and stable production, a comprehensive reservoir evaluation and favorable area selection are urgently needed to provide a scientific basis for gas well deployment and ensure efficient development of the field.

[0139] Step S1: According to the implementation steps, 8 index parameters of 184 wells in the block were selected to construct a parameter evaluation matrix. The data are shown in Table 1.

[0140] Table 1 Index parameters of some gas wells in a block of the ancient gas reservoir in Jingbian gas field

[0141]

[0142]

[0143] Step S2: normalize the data in the original parameter index evaluation table. The data processing results are shown in Table 2.

[0144] Table 2 Normalization results of some gas well index parameters in a block of the ancient gas reservoir in Jingbian gas field

[0145]

[0146]

[0147] Step S3: Calculate the entropy value E of each indicator for the normalized data. j , and use the entropy value to determine the entropy weight w of each indicator in the evaluation process j , see Table 3. It can be seen that the weight values ​​of formation coefficient, energy storage coefficient and gas layer thickness are relatively large, and they are the main factors for reservoir evaluation.

[0148] Table 3 Entropy values ​​and weights of various parameters of ancient gas reservoirs in Jingbian gas field

[0149]

[0150] Step S4: Calculate the comprehensive score G of each reservoir layer according to the reservoir evaluation score formula s For multiple reservoirs of the same well, the evaluation scores of the multiple reservoirs are weighted averaged according to the reservoir thickness. The comprehensive score of the gas well G is obtained based on the comprehensive score of a single reservoir and the comprehensive score after weighted processing. t , the results are shown in Table 4.

[0151] Table 4 Calculation results of comprehensive scores of some gas wells in a block of the ancient gas reservoir in Jingbian Gas Field

[0152]

[0153]

[0154] Step S5: Draw a comprehensive score cumulative frequency curve based on the comprehensive score of the gas wells in the block ( Figure 2 ), as can be seen from the figure, the cumulative frequency curve of the comprehensive score presents a four-segment distribution, and the comprehensive scores at the intersection points are 0.7, 1.0 and 1.7 respectively. Based on this, the reservoirs are divided into four categories: Class I reservoir gas wells have a comprehensive score ≥1.7, Class II reservoir gas wells have a comprehensive score of 1.0-1.5, Class III reservoir gas wells have a comprehensive score of 0.7-1.0, and Class IV reservoir gas wells have a comprehensive score <0.7.

[0155] Step S6: Draw contour maps based on the comprehensive scores of gas wells and divide reservoir classification characteristics on the plane according to reservoir classification standards, and prioritize well placement in Class I+II reservoirs as favorable areas. Figure 3 )

[0156] Based on the same concept, the present invention also discloses a device for comprehensive evaluation of tight gas reservoirs and optimization of favorable areas. Figure 4 Schematic diagram of a device for comprehensive evaluation of tight gas reservoirs and optimization of favorable areas according to the present invention. Figure 4 As shown, the device includes: a determination module 201, which is used to optimize the reservoir evaluation index parameter system and determine the set of index parameters; a construction module 202, which is used to determine the well set in the study area and construct an index parameter evaluation matrix; a normalization module 203, which is used to normalize the index parameter evaluation matrix; an acquisition module 204, which is used to determine the index parameter weights using the entropy weight method and obtain the entropy weight of each index parameter; a calculation module 206, which is used to obtain the reservoir evaluation comprehensive index based on the entropy weight of the index parameter and the normalized matrix, and calculate the comprehensive score of the gas well; a quantitative division module 206, which is used to quantitatively divide the comprehensive score of the gas well and determine the quantitative evaluation standard of the reservoir; and a selection module 207, which is used to draw a planar distribution map of the reservoir type in the study area according to the quantitative evaluation standard of the reservoir and select favorable development areas.

[0157] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for comprehensive evaluation of tight gas reservoirs and optimization of favorable areas, characterized in that: The method comprises: Step S1, optimizing a reservoir evaluation index parameter system and determining a set of index parameters; Step S2: determine the well set in the study area and construct an indicator parameter evaluation matrix; Step S3, normalizing the index parameter evaluation matrix; Step S4: Determine the weight of the indicator parameters using the entropy weight method to obtain the entropy weight of each indicator parameter; Step S5: obtaining a comprehensive reservoir evaluation index based on the entropy weight of the index parameters and the normalized matrix, and calculating a comprehensive score of the gas well; Step S6: quantitatively classify the comprehensive scores of the gas wells and determine the quantitative evaluation standard of the reservoir; Step S7: Draw a planar distribution map of reservoir types in the study area based on the reservoir quantitative evaluation criteria, and select favorable areas for development.

2. The method for comprehensive evaluation of tight gas reservoirs and optimization of favorable areas according to claim 1, characterized in that: The index parameters include: porosity, permeability, gas saturation, gas layer thickness, formation coefficient, reservoir coefficient, permeability variation coefficient and breakthrough coefficient.

3. A method for comprehensive evaluation of tight gas reservoirs and optimization of favorable areas according to claim 1 or 2, characterized in that: The step S2, determining the well set in the study area and constructing an index parameter evaluation matrix, includes: Based on the principle of covering the entire study area, the exploration wells, appraisal wells and development wells in the study area are screened, and wells that can obtain logging data and gas production data are selected; For n wells and l reservoirs in the selected study area, the reservoir set to be evaluated is determined, which is denoted as: R = (R1, R2, ..., R l ); Combined with the set of index parameters F=(F1,F2,…,F m ), construct the index evaluation matrix A of m parameters in the study area:

4. The method for comprehensive evaluation of tight gas reservoirs and optimization of favorable areas according to claim 2, characterized in that: The step S3, normalizing the index parameter evaluation matrix, includes: Step S31: unifying the dimensions of index parameters in different units; including: 1) For positive index parameters, including porosity, permeability, gas saturation, gas layer thickness, formation coefficient and reservoir coefficient, the following formula is used for normalization: 2) For negative indicator parameters, including permeability variation coefficient and breakthrough coefficient, the following formula is used for normalization: Step S32: The matrix after normalization processing is:

5. The method for comprehensive evaluation of tight gas reservoirs and selection of favorable areas according to claim 1, characterized in that: The step S4, determining the weight of the indicator parameters using the entropy weight method to obtain the entropy weight of each indicator parameter, includes: Step S41: Calculate the entropy value of each indicator parameter and use the entropy value to determine the weight of each indicator parameter in the evaluation process; including: 1) The calculation formula of the entropy value of the jth indicator parameter is: in: k=1 / ln l; When f ij = 0, let f ij ln f ij =0. 2) Calculate the weight of the j-th indicator parameter based on the entropy value of the j-th indicator parameter: in: w j ∈[0,1]； Step S42: Use this method to obtain the weight of each indicator parameter to obtain the entropy weight corresponding to each indicator parameter: W=w1,w2,…,w m 。 6. The method for comprehensive evaluation of tight gas reservoirs and selection of favorable areas according to claim 1, characterized in that: The step S5, obtaining a comprehensive reservoir evaluation index based on the entropy weight of the indicator parameters and the normalized matrix, and calculating a comprehensive score of the gas well, includes: Entropy weight w based on indicator parameters j and the normalized matrix B to calculate the comprehensive evaluation index of each reservoir in the study area; The evaluation comprehensive index of different reservoir index parameters is summed to obtain the evaluation index of each reservoir: For multiple reservoirs in the same well, the evaluation indexes of the multiple reservoirs are weighted averaged according to the thickness of the gas layers to obtain the comprehensive score of the gas well.

7. A method for comprehensive evaluation of tight gas reservoirs and selection of favorable areas according to claim 1, 5 or 6, characterized in that: The step S6, quantitatively classifying the comprehensive scores of the gas wells and determining the quantitative evaluation criteria for the reservoir, includes: Draw a cumulative frequency graph of the gas well comprehensive score; The comprehensive scores of gas wells in the same type of reservoir have similar slopes on the cumulative frequency curve. The boundaries of reservoir quantitative evaluation are determined based on the comprehensive scores of gas wells corresponding to the intersection points a, b, and c of different slopes. The comprehensive score of gas wells in Class I reservoirs is ≥ c; Comprehensive scores of gas wells in Class II reservoirs are b to c; Comprehensive scores of gas wells in Class III reservoirs are a to b; Comprehensive score of gas wells in Class IV reservoirs <a。 8. The method for comprehensive evaluation of tight gas reservoirs and selection of favorable areas according to claim 1, characterized in that: The step S7, drawing a planar distribution map of reservoir types in the study area according to the reservoir quantitative evaluation standard and selecting favorable areas for development, includes: Draw contour maps of the comprehensive scores of gas wells, divide the reservoirs on the plane according to the quantitative evaluation standards of reservoirs, and delineate the range of each type of reservoir. Select Class I + II reservoirs as favorable areas, and guide the deployment of development wells based on the current status of the well network and the utilization of reserves.

9. A device for comprehensive evaluation of tight gas reservoirs and optimization of favorable areas, characterized in that: The device comprises: A determination module is used to optimize the reservoir evaluation index parameter system and determine the set of index parameters; Construction module, used to determine the well set in the study area and construct the indicator parameter evaluation matrix; Normalization module, used for normalization of indicator parameter evaluation matrix; The acquisition module is used to determine the weight of the indicator parameters using the entropy weight method to obtain the entropy weight of each indicator parameter; The calculation module is used to obtain the comprehensive index of reservoir evaluation based on the entropy weight of the indicator parameters and the normalized matrix, and calculate the comprehensive score of the gas well; Quantitative classification module, used to quantitatively classify the comprehensive scores of gas wells and determine the quantitative evaluation standards of reservoirs; The optimization module is used to draw a planar distribution map of reservoir types in the study area based on the quantitative reservoir evaluation standards and to select favorable development areas.

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