Method for evaluating reservoir quality of volcanic rock gas storage

Abstract

The invention discloses a volcanic rock gas storage reservoir quality evaluation method, which comprises the following steps: obtaining reservoir dynamic characteristics and reservoir static characteristics for reservoir evaluation, and constructing a hierarchical structure model based on an analytic hierarchy process by using the reservoir dynamic characteristics and the reservoir static characteristics; according to the hierarchical structure model, constructing a judgment matrix, and obtaining a weight value omega i of each evaluation index for reservoir evaluation; performing comprehensive evaluation on each evaluation index to obtain a quantitative score mi of the evaluation index; calculating a volcanic rock gas storage evaluation index comprehensive value M according to the quantitative score mi in combination with the weight value omega i; the problem that at present, research on volcanic rock gas storage reservoir evaluation mainly pays attention to static characteristics and does not involve dynamic characteristics is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of natural gas underground storage and gas reservoir engineering, and in particular to a method for dynamically evaluating reservoir quality of a volcanic gas storage reservoir based on a hierarchical analysis method. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0003] As the main tool for natural gas storage, peak load regulation and supply guarantee, underground natural gas storage is an important means to ensure the national gas supply security. As a gas storage geological body with reservoir and gas storage structure as the core, the most important factor for its construction success is whether the reservoir can be injected, extracted and stored.

[0004] In recent years, a large number of volcanic gas reservoirs have been discovered in the Songliao Basin and Junggar Basin in my country. The development and construction of volcanic gas storage facilities requires accurate evaluation of the reservoir quality under the dynamic injection and production operation of the gas storage facilities. However, there is currently no precedent for the reconstruction of volcanic gas reservoirs into gas storage facilities.

[0005] The complexity of volcanic geological characteristics and the uniqueness of dynamic operation and injection and production of gas storage make it difficult to understand the dynamic and static characteristics of reservoirs in the construction of volcanic gas storage. Among them, the reservoir characteristics of volcanic gas reservoirs are very different from those of ordinary sandstone and carbonate gas reservoirs. Its reservoir storage space types are diverse, heterogeneity is serious, seepage characteristics are complex, fractures are widely and unevenly developed, and reservoir rocks are highly sensitive to stress. At the same time, in the dynamic production process of gas storage, large flow, high speed, and high intensity injection and production are required in a short period of time, which brings huge uncertainty to the reservoir evaluation of volcanic gas reservoirs for gas storage.

[0006] At present, the research on reservoir evaluation of volcanic gas storage mainly focuses on static characteristics, such as gas reservoir geological characteristics, lithology and lithofacies, reservoir space characteristics and pore and fracture development characteristics, but does not pay attention to the dynamic restrictive relationship between the reservoir and the alternating injection-production environment of the formation. It is difficult to determine the negative impact of various factors such as water invasion, stress sensitivity, rock and bound water deformation on the reservoir quality of volcanic gas storage under the dynamic environment of the formation.

[0007] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may contain information that does not constitute prior art. Summary of the invention

[0008] In view of this, the present disclosure provides a method for evaluating the reservoir quality of a volcanic gas storage reservoir, which solves the problem that current research on volcanic gas storage reservoir evaluation mainly focuses on static characteristics but does not involve dynamic characteristics.

[0009] To achieve the above-mentioned purpose of the invention, the method for evaluating the reservoir quality of a volcanic gas storage reservoir comprises:

[0010] Acquire reservoir dynamic characteristics and reservoir static characteristics as reservoir evaluation, and construct a hierarchical structure model based on hierarchical analysis method using the reservoir dynamic characteristics and the reservoir static characteristics;

[0011] According to the hierarchical model, a judgment matrix is ​​constructed to obtain the weight value ω of each evaluation index used in the reservoir evaluation. i ;

[0012] Comprehensively evaluate each evaluation index to obtain its quantitative score m i ;

[0013] According to the quantitative score m i , combined with the weight value ω i , and the comprehensive value M of the evaluation index of volcanic gas storage is calculated.

[0014] In the present disclosure and possible embodiments, the reservoir static characteristics include reservoir macroscopic static characteristics and reservoir microscopic static characteristics;

[0015] The macroscopic static characteristics of the reservoir include water body characteristics, heterogeneity, effective thickness and storage-permeability pattern; the microscopic static characteristics of the reservoir include porosity, permeability and fracture development characteristics.

[0016] In the present disclosure and possible embodiments, the reservoir dynamic characteristics include fluid component characteristics, seepage characteristics and reservoir mechanical characteristics;

[0017] The fluid component characteristics include initial gas saturation, carbon dioxide content and natural gas relative density; the seepage characteristics include irreducible water saturation and pore space utilization efficiency; the reservoir mechanical characteristics include rock stress sensitivity and rock alternating fatigue characteristics.

[0018] In the present disclosure and possible embodiments, the method for constructing the judgment matrix includes:

[0019] According to the hierarchical model, through literature research, expert scoring and numerical simulation sensitivity analysis, each evaluation index is judged and compared in pairs to obtain the relative importance of each evaluation index, and the judgment matrix is ​​constructed using the 1-9 scaling method.

[0020] In the present disclosure and possible embodiments, the maximum eigenvalue and eigenvector of each judgment matrix are calculated using the sum-product method, and a consistency check is performed;

[0021] Determine the weight value ω of each evaluation index based on the maximum eigenvalue and eigenvector of each judgment matrix i .

[0022] In the present disclosure and possible embodiments, a classification evaluation standard for volcanic reservoir quality is obtained, and the comprehensive evaluation is performed on each evaluation index according to the classification evaluation standard to obtain the quantitative score m i .

[0023] In the present disclosure and possible embodiments, the formula for performing the calculation is:

[0024]

[0025] Where: m i is the quantitative score of each evaluation index; i is the weight value of each evaluation index; i=1, 2,...n.

[0026] The present disclosure has the following beneficial effects:

[0027] The volcanic rock gas storage reservoir quality evaluation method based on the analytic hierarchy process proposed in the present invention establishes evaluation standards by combining the reservoir characteristics of the volcanic rock gas storage reservoir and various dynamic and static parameters of the volcanic rock gas storage reservoirs built at home and abroad, constructs a reservoir evaluation model for the volcanic rock gas storage reservoir by using five levels: static macroscopic characteristics of the volcanic rock reservoir, static microscopic characteristics of the reservoir, fluid component characteristics, fluid seepage characteristics, and reservoir mechanical characteristics, determines the quantitative scores and weights of dynamic and static evaluation indicators related to the reservoir quality, obtains the comprehensive value of the evaluation indicators of the volcanic rock gas storage reservoir, and realizes the quantitative evaluation of the reservoir quality of the volcanic rock gas storage reservoir; the method of the present invention realizes the intuitive quantification of the static and dynamic evaluation standards of the reservoir, has reliable results, strong applicability, meets the reservoir evaluation requirements in the complex geological environment of the gas storage reservoir, and provides a reference for the subsequent injection and production operation and design optimization of the gas storage reservoir. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0029] Figure 1 is a flow chart of a method for evaluating reservoir quality of a volcanic gas storage facility according to an embodiment of the present disclosure;

[0030] Figure 2 It is a hierarchical framework diagram of reservoir quality evaluation of a volcanic gas storage reservoir according to an embodiment of the present disclosure;

[0031] Figure 3 is a bar chart of the weight ratios of reservoir evaluation indicators of a volcanic gas storage reservoir according to an embodiment of the present disclosure;

[0032] Figure 4 It is a curve showing the change of water invasion replacement coefficient of the gas reservoir in the Shengping volcanic rock gas storage reservoir according to the embodiment of the present disclosure. DETAILED DESCRIPTION

[0033] The present disclosure is described below based on embodiments, but it is worth noting that the present disclosure is not limited to these embodiments. In the detailed description of the present disclosure below, some specific details are described in detail. However, for the parts that are not described in detail, those skilled in the art can also fully understand the present disclosure.

[0034] In addition, those skilled in the art should understand that the drawings are only provided to illustrate the purpose, features and advantages of the present disclosure, and the drawings are not actually drawn to scale.

[0035] At the same time, unless the context clearly requires otherwise, the words "include", "comprises" and similar words throughout the specification and claims should be interpreted as inclusive rather than exclusive or exhaustive; that is, the meaning is "including but not limited to".

[0036] The method of the present invention investigates a large number of volcanic gas reservoir parameters and reservoir characteristics of domestic gas storages, focuses on the dynamic changes of reservoirs under the multi-cycle injection and production environment of gas storages, considers the static characteristics of reservoirs, rock mechanical characteristics, fluid seepage characteristics, formation water bodies and injection and production operation parameters of gas storages, adopts a dynamic and static combined analysis method, analyzes the reservoir characteristics of gas storages in a more comprehensive manner, and establishes a comprehensive evaluation method for the reservoir quality of volcanic gas storages, specifically adopts a qualitative and quantitative combined hierarchical analysis method, uses a 1-9 scaling method to comprehensively score the preferred evaluation indicators, obtains the relative importance ratios between the same-level influencing factors, constructs a judgment matrix, and obtains the maximum eigenvalue and its corresponding eigenvector, which is the weight value ω of the evaluation indicator. i At the same time, a classification evaluation standard suitable for volcanic rock reservoir quality is established, and the evaluation standard is numerically quantified. With reference to the evaluation standard, a comprehensive evaluation is conducted on each evaluation index of the reservoir to obtain the quantitative score m of each evaluation index. i ; Finally, according to the quantitative score m of each evaluation index i and weight value ω i The comprehensive value M of the evaluation index of the volcanic gas storage reservoir is obtained, and the quantitative evaluation of the reservoir quality of the volcanic gas storage reservoir is realized.

[0037] Figure 1 is a flow chart of a method for evaluating reservoir quality of a volcanic gas storage reservoir according to an embodiment of the present disclosure; Figure 1 As shown, the steps of the method for evaluating reservoir quality of volcanic gas storage are as follows:

[0038] Step S01: Establish a reservoir evaluation model for volcanic gas storage based on the analytic hierarchy process:

[0039] A hierarchical system for evaluating the reservoir quality of volcanic gas storage is constructed by using reservoir dynamic characteristics and reservoir static characteristics. According to the characteristics of the dynamic operation process of the volcanic gas storage, the embodiment of the present disclosure specifically selects two reservoir static characteristics, namely, macroscopic static characteristics and microscopic static characteristics of the reservoir, and three reservoir dynamic characteristics, namely, fluid component characteristics, fluid seepage characteristics, and reservoir rock mechanics characteristics. That is, the hierarchical system is constructed from these five levels, wherein:

[0040] (1) Reservoir macroscopic static characteristics and reservoir microscopic static characteristics. The basic understanding of the reservoir static characteristics of volcanic gas reservoirs converted into gas storage facilities is mainly formed through the early geological and well logging data of volcanic gas reservoirs and indoor test data. Among them, the reservoir macroscopic static characteristics include effective thickness, volcanic rock storage and permeability mode, heterogeneity, and edge and bottom water characteristics; the reservoir microscopic static characteristics include porosity, permeability, and fracture development characteristics;

[0041] (2) Fluid component characteristics and fluid seepage characteristics. Fluid component characteristics are mainly obtained by chemical analysis of fluids, including natural gas composition analysis (C1-C8, O2, N2, etc.), CO2 content analysis, natural gas relative density and other parameter analysis, specifically including initial gas saturation, carbon dioxide content and natural gas relative density; fluid seepage characteristics are mainly obtained by analyzing complex injection and production mechanisms such as gas-water multiphase seepage characteristics, reservoir production efficiency and gas-water migration during injection and production through indoor microscopic storage and permeability and spatial production tests, specifically including irreducible water saturation and pore space utilization efficiency;

[0042] (3) For the mechanical characteristics of reservoir rocks, the basic understanding of the mechanical characteristics of reservoir rocks is mainly obtained through the rock multi-cycle stress sensitivity test and the alternating mechanical fatigue test. The specific implementation standard is "Method for Determination of Rock Porosity and Permeability under Overburden Pressure"

[0043] (SY / T6385-1999), the stress sensitivity evaluation standard refers to SY / T5358-2010; for the reservoir rock mechanical characteristics, the rock stress sensitivity and rock alternating fatigue characteristics are specifically selected.

[0044] Based on the analytic hierarchy process, the above 14 characteristics are used as evaluation indicators to construct a hierarchical structure model for evaluating the reservoir quality of the volcanic gas storage reservoir in the embodiment of the present disclosure. Figure 2 As shown, A is the target layer, B1-B5 are the criterion layer, C1-C14 are the solution layer; B1-B5 are the first-level indicators, and C1-C14 are the second-level indicators.

[0045] It should be noted that the evaluation index selection in step S01 can construct different reservoir evaluation models for different research objectives due to the different specific geological characteristics of the volcanic gas storage reservoir, but the method and concept of establishing the hierarchical analysis method framework model are the same.

[0046] Step S02: Construct a judgment matrix:

[0047] First, the relative importance of each factor is obtained by investigating existing research results at home and abroad, expert scoring, and numerical simulation sensitivity analysis. Specifically, the 1-9 scale method is used to determine the appropriate scale, as shown in Table 1: the equally important scale value is 1, the slightly important scale value is 3, the relatively important scale value is 5, the strongly important scale value is 7, and the absolutely important scale value is 9. 2, 4, 6, and 8 represent the compromise values ​​between the above two judgment levels;

[0048] Table 2 Classification criteria for relative importance of factors

[0049] value illustrate 1 <![CDATA[A i With A j Compared, both contribute equally to the goal]]> 3 <![CDATA[A i With A j Comparison, the former is slightly more advantageous than the latter]]> 5 <![CDATA[A i With A j Comparison shows that the former is more advantageous than the latter]]> 7 <![CDATA[A i With A j Comparison shows that the former is more advantageous than the latter, and has obvious advantages]]> 9 <![CDATA[A i With A j Comparison, the former is definitely more advantageous than the latter]]> 2,4,6,8 The importance is between two adjacent values.

[0050] Second, construct the corresponding judgment matrix based on the determined scale value; element values: a ij ·a jk =a ik , i,j,k=1,2,…n, a ii = 1. According to the hierarchical model, the factors are judged and compared in pairs to construct a judgment matrix, which is expressed as follows.

[0051]

[0052] Step S03: Calculate eigenvalues ​​and eigenvectors, and perform consistency check:

[0053] (1) Calculate eigenvalues ​​and eigenvectors;

[0054] Use the sum-product method to calculate the maximum eigenvalue and eigenvector of the judgment matrix; normalize the judgment matrix by column, b ij =a ij / ∑a ij , sum the normalized matrix row by row, c i =∑b ij ; After normalizing the column vector, we get the eigenvector, and find the maximum eigenvalue corresponding to the eigenvector. The eigenvector is the weight of each evaluation index.

[0055] (2)Consistency test

[0056] In order to check whether the weight coefficients are reasonably distributed, the random consistency index is used. When the CR value is less than 0.1, the matrix is ​​judged to meet the consistency test, otherwise the matrix needs to be re-evaluated until satisfactory consistency is achieved.

[0057] Step S04: Determine the weight coefficient of each indicator:

[0058] The evaluation index levels of volcanic gas storage reservoirs are ranked in total to obtain the weight value of each analysis item; specifically, after obtaining the relative importance of each element at the same level, the overall comprehensive importance of each level of elements is calculated. Among them, the weight of each secondary evaluation index relative to the target layer of the volcanic gas storage reservoir is the product of the weight of the secondary index relative to the primary index and the weight of the primary index relative to the target layer.

[0059] Step S05: Establishment of evaluation criteria and classification and quantification of target reservoir evaluation indicators:

[0060] By investigating the reservoir parameters of volcanic gas reservoirs at home and abroad and the reservoir characteristics of domestic gas storages, combined with the reservoir characteristics of volcanic gas reservoirs in my country and the technical requirements for the development and design of gas storages, a classification evaluation standard suitable for the quality of volcanic reservoirs is established. The disclosed embodiment quantifies the excellent, good, medium and poor of the classification evaluation standard into 10 points, 8 points, 6 points and 4 points respectively.

[0061] Referring to the classification evaluation standard, combined with the previous geological data, well logging data, indoor test data, and numerical simulation results of the target volcanic gas storage reservoir, a comprehensive evaluation was conducted on each evaluation index to obtain the quantitative score m of each evaluation index. i .

[0062] Among them, some classification evaluation criteria are shown in Tables 3 and 4 below:

[0063] Table 3 Classification and evaluation criteria for Shengping volcanic rock gas storage (static)

[0064]

[0065]

[0066] Table 4 Classification and evaluation criteria for Shengping volcanic rock gas storage (dynamic)

[0067]

[0068] The inventors of the present application have investigated a large number of volcanic gas storage reservoir-related parameters and reservoir evaluation standards, indoor test results, etc., and can basically refer to these standards to evaluate the good, medium and poor quality of domestic volcanic gas storage reservoir-related parameters.

[0069] Step S06: Calculate the comprehensive value M of the target gas storage reservoir quality index:

[0070] According to the quantitative score m of each evaluation index in step S05 i , combined with the relative weight value of each evaluation index obtained by the hierarchical analysis method i , the comprehensive value M of the evaluation index of volcanic gas storage is calculated, and the quantitative evaluation of volcanic gas storage is realized by comparing with Table 5.

[0071] In the evaluation model, the calculation process of the comprehensive index value M is as follows:

[0072]

[0073] Where: m i is the quantitative score of each evaluation index; i is the weight value of each evaluation index relative to the volcanic rock reservoir; i = 1, 2, ..., 13, 14.

[0074] Table 5 Evaluation and classification standards of volcanic gas storage indicators

[0075] Comprehensive scoring of reservoir quality of volcanic gas storage Index comprehensive value M Countermeasures and suggestions optimal 9～10 Can be used as a good reservoir with good gas storage capacity and operation ability suitable 8～9 Suitable for gas storage, relatively poor operating capacity Basic suitability 6～8 The capacity to reach full capacity is poor, and the reservoir needs to be transformed Unsuitable ＜6 Not suitable for gas storage operation, difficult to reach full capacity and production

[0076] Example

[0077] This example evaluates the reservoir quality of the gas storage facility rebuilt from the Shengping volcanic gas reservoir in the Songliao Basin.

[0078] Among them, the constructed hierarchical model for reservoir dynamic evaluation of Shengping volcanic rock gas storage is as follows: Figure 2 shown.

[0079] Referring to the classification evaluation standards in Table 3 and Table 4, a comprehensive evaluation is conducted on the reservoir quality evaluation indicators of Shengping volcanic rock gas storage. The specific ratings are as follows:

[0080] 1. Macroscopic static characteristics of reservoir

[0081] 1.1 Storage and seepage mode:

[0082] The Shengping volcanic rock gas storage has a complex and diverse reservoir space type and complex structure, as shown in Table 6 below:

[0083] Table 6 Storage and permeability model of Shengping volcanic rock gas storage

[0084]

[0085] Combined with Table 6 above, the reservoir of Shengping Gas Storage is evaluated from the perspective of storage and permeability mode. The reservoir space types are complex and diverse, with two main types of reservoir space developed: pore type and fracture-pore type. The overall evaluation is "good".

[0086] 1.2 Effective thickness:

[0087] The effective thickness of volcanic rocks ranges from 50 to 130 m, with an average effective thickness of 50.1 m. If the effective thickness is greater than 30 m, the overall evaluation is “excellent”.

[0088] 1.3 Heterogeneity:

[0089] There are different types of reservoirs developed in volcanic rock gas storage, with great differences in seepage capacity and distribution in plane. Vertically, the development depths of high-permeability reservoirs in different regions are scattered, locally concentrated, and highly heterogeneous. From the perspective of non-qualitative evaluation, the comprehensive evaluation of the Shengping Gas Storage Reservoir reservoir is "poor".

[0090] 1.4 Water characteristics:

[0091] According to the material balance model, the water invasion replacement coefficient of Shengshen 2-1 gas reservoir is currently 0.44, and the water invasion replacement coefficient of Shengping gas storage is currently 0.44. Figure 4 The movable edge bottom water body is large. In the early stage of exploitation, gas wells are prone to large amounts of water discharge or flooding. During the stable production period of the gas reservoir, the water invasion characteristic curve rises linearly.

[0092] Combined with the classification and evaluation criteria in Table 3, the comprehensive evaluation of the reservoir of Shengping Gas Storage is "poor" based on water body characteristics.

[0093] 2. Microscopic static characteristics of reservoir

[0094] 2.1 Porosity:

[0095] The reservoir porosity ranges from 4.0% to 27.5%, with an average of 8.4%;

[0096] 2.2 Permeability:

[0097] The permeability ranged from 0.006 to 319 mD, with an average of 1.19 mD;

[0098] 2.3 Degree of crack development:

[0099] According to the statistics of fracture parameters from imaging logging (Daqing Shengping Gas Storage Feasibility Study Report, Evaluation of Reservoir Fracture Development Degree of Deep Volcanic Gas Reservoirs), the average density of fractures is 4.72 / m.

[0100] Combined with Table 3, the reservoir of Shengping Gas Storage is evaluated from the perspective of reservoir micro-static characteristics. The porosity is comprehensively evaluated as "medium", the permeability is comprehensively evaluated as "good", and the fracture development degree is comprehensively evaluated as "medium".

[0101] 3. Fluid component characteristics

[0102] The characteristics of the fluid components in Shengping Gas Storage are shown in Table 7:

[0103] Table 7 Characteristics of fluid components in Shengping gas storage

[0104]

[0105]

[0106] As shown in Table 7, the original gas saturation of the Shengping gas storage reservoir is 0.6, the original bound water saturation of the gas reservoir is 0.4, the methane content of the Yingcheng Formation is between 91.43% and 96.22%, the carbon dioxide content is between 1.18% and 3.60%, and the relative density of natural gas is between 0.58 and 0.61 (including the feasibility of converting the volcanic gas reservoir with edge and bottom water into an underground gas storage). The natural gas in the Shengping area is mainly dry gas, but there is a certain amount of non-hydrocarbon gas, especially the high carbon dioxide content.

[0107] As shown in Table 4, based on the evaluation of fluid component characteristics, the initial gas saturation of the Shengping gas storage is comprehensively evaluated as "excellent"; the carbon dioxide content is comprehensively evaluated as "medium"; and the relative density of natural gas is comprehensively evaluated as "excellent".

[0108] 4. Seepage characteristics

[0109] 4.1 Irreducible water saturation

[0110] In the early core test analysis, 26 samples in the area were analyzed, and their irreducible water saturation levels were 27.1% to 47.62%, with an average of 38.9%. After multiple rounds of gas-water inter-drive permeability characteristics analysis, the irreducible water saturation of the rock samples after gas-water inter-drive was in the range of 40% to 80%.

[0111] 4.2 Pore space utilization efficiency

[0112] The results of the multi-cycle injection and production pore space utilization test showed that after 6 cycles of injection and production, the space utilization efficiency of the pure gas zone before reservoir construction was 87.2%, the gas-driven pure gas zone was 58.0%, and the gas-water transition zone was 37.6%.

[0113] As shown in Table 4, the reservoir of Shengping Gas Storage is evaluated from the perspective of seepage characteristics, and the comprehensive evaluation of irreducible water saturation is "poor", and the comprehensive evaluation of pore space utilization efficiency is "poor".

[0114] 5. Reservoir mechanical characteristics

[0115] 5.5 Stress sensitivity

[0116] Through the reservoir rock stress sensitivity test, the results show that different types of rocks have different stress sensitivities, but the permeability damage rate of fractured cores is generally in the range of >70%. For dense rock samples, the stress sensitivity is relatively light and the damage is low. For safety reasons, the stress sensitivity of fractured rock samples is mainly used.

[0117] 5.2 Characteristics of rock alternating fatigue

[0118] Through the reservoir alternating mechanical fatigue test, the results showed that the stability of the reservoir rock under the alternating injection and production conditions was good, no damage occurred, and it was rated as "excellent".

[0119] As shown in Table 4, the reservoir of Shengping Gas Storage is evaluated from the perspective of reservoir mechanics characteristics. The stress sensitivity is strong, the damage rate is greater than 70%, and the comprehensive evaluation is "poor". Since no damage has occurred and the stability is good, the comprehensive evaluation of rock alternating mechanics is "excellent".

[0120] Based on literature research, expert scoring, and numerical simulation methods, the relative importance of each evaluation index is determined and a judgment matrix is ​​constructed. The eigenvalue is calculated and a consistency test is performed. Table 8 shows the calculation results of the eigenvectors and weights of each reservoir evaluation index. The consistency test has been passed. The weight of each evaluation index is determined. Figure 3 shown.

[0121] Table 8 Calculation results of eigenvectors and weights of each evaluation index in the hierarchical analysis

[0122]

[0123] Based on the geological and logging data of the target gas storage, indoor physical simulation experiments and numerical simulation results, we have formed an understanding of the various evaluation indicators of volcanic gas storage. According to the classification evaluation standards in Table 3 and Table 4, we have obtained the quantitative scores of the 14 evaluation indicators selected in the hierarchical framework. i , which are 6, 10, 4, 4, 6, 8, 4, 10, 6, 10, 6, 8, 4, 10 respectively.

[0124] According to the quantitative scores m of each evaluation index obtained above i , combined with the weight value of each evaluation index relative to the volcanic reservoir ω i According to the following formula, the comprehensive index value M of the target volcanic gas storage reservoir is 7.62.

[0125]

[0126] From Table 5, we can see that the comprehensive reservoir quality value of the volcanic rock gas storage in the Songliao Basin is within the range of 6 to 8, which is basically suitable for reconstruction of gas storage, but the capacity to reach capacity and production is poor, and the reservoir needs to be transformed.

[0127] The evaluation results are consistent with the results of the previous geological survey and demonstration, and the results are reliable and applicable to actual projects.

[0128] The above-described embodiments are only embodiments of the present disclosure, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the present disclosure. It should be noted that, for a person of ordinary skill in the art, without departing from the concept of the present disclosure, several variations, equivalent substitutions, improvements, etc. may be made, all of which fall within the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure shall be subject to the attached claims.

Claims

1. A method for evaluating reservoir quality of a volcanic gas storage reservoir, characterized in that: include: Acquire reservoir dynamic characteristics and reservoir static characteristics as reservoir evaluation, and construct a hierarchical structure model based on hierarchical analysis method using the reservoir dynamic characteristics and the reservoir static characteristics; According to the hierarchical model, a judgment matrix is ​​constructed to obtain the weight values ​​of each evaluation index used in the reservoir evaluation. ωi ; Comprehensively evaluate each evaluation index to obtain its quantitative score mi ; According to the quantitative score mi , combined with the weight value ωi , and the comprehensive value M of the evaluation index of volcanic gas storage is calculated.

2. The method for evaluating reservoir quality of a volcanic gas storage according to claim 1, characterized in that: The reservoir static characteristics include reservoir macroscopic static characteristics and reservoir microscopic static characteristics; The macroscopic static characteristics of the reservoir include water body characteristics, heterogeneity, effective thickness and storage-permeability pattern; the microscopic static characteristics of the reservoir include porosity, permeability and fracture development characteristics.

3. The method for evaluating reservoir quality of a volcanic gas storage according to claim 2, characterized in that: The reservoir dynamic characteristics include fluid component characteristics, seepage characteristics and reservoir mechanical characteristics; The fluid component characteristics include initial gas saturation, carbon dioxide content and natural gas relative density; the seepage characteristics include irreducible water saturation and pore space utilization efficiency; the reservoir mechanical characteristics include rock stress sensitivity and rock alternating fatigue characteristics.

4. The method for evaluating reservoir quality of a volcanic gas storage according to claim 3, characterized in that: The construction method of the judgment matrix includes: According to the hierarchical model, through literature research, expert scoring and numerical simulation sensitivity analysis, each evaluation index is judged and compared in pairs to obtain the relative importance of each evaluation index, and the judgment matrix is ​​constructed using the 1-9 scaling method.

5. The method for evaluating reservoir quality of a volcanic gas storage according to claim 4, characterized in that: The maximum eigenvalue and eigenvector of each judgment matrix are calculated by sum-product method, and consistency check is performed; Determine the weight value of each evaluation index based on the maximum eigenvalue and eigenvector of each judgment matrix ωi .

6. The method for evaluating reservoir quality of a volcanic gas storage according to claim 5, characterized in that: Obtain the classification evaluation standard of volcanic rock reservoir quality, and perform the comprehensive evaluation on each evaluation index according to the classification evaluation standard to obtain the quantitative score mi .

7. The method for evaluating reservoir quality of a volcanic gas storage according to any one of claims 1 to 6, characterized in that: The formula for performing the calculation is: Where: m i is the quantitative score of each evaluation index; ωi is the weight value of each evaluation index; i=1, 2,...n.

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