Method and device for determining favorable areas for storage conditions of black rock series unconventional natural gas

Abstract

The present invention provides a method and device for determining a favorable area for the preservation of black rock type unconventional natural gas. The method comprises: obtaining evaluation parameters of the target black rock type unconventional natural gas in the area to be evaluated; wherein the evaluation parameters include reservoir parameters, top and bottom plate parameters, cap rock parameters, formation parameters and fault parameters; constructing corresponding sealing indicators according to the evaluation parameters; determining the parameter weights of each sealing indicator according to each sealing indicator, and determining a comprehensive preservation indicator according to each sealing indicator and its corresponding parameter weight; determining the favorable area for the preservation of the target black rock type unconventional natural gas according to the comprehensive preservation indicator. The present invention can improve the scientific effectiveness of determining the favorable area for the preservation of black rock type unconventional natural gas.

Description

Technical Field

[0001] The present invention relates to the technical field of natural gas exploration, and in particular to a method and device for determining a favorable area for the preservation of black rock series unconventional natural gas. Background Art

[0002] Black rock formations are rich in organic matter and extremely dense. The gases formed and stored in them belong to unconventional natural gas resources. This type of natural gas reservoir has the characteristics of self-generation and self-storage, integrated source and reservoir, continuous distribution and no obvious gas-water interface. Black rock type unconventional natural gas includes shale gas, coalbed methane, tight carbonate gas, etc. Shale gas and coalbed methane usually appear simultaneously in coal-bearing formations, thus forming widely distributed coal-bearing gas. Unconventional natural gas preservation conditions are one of the prerequisites for its enrichment and accumulation. The reservoir itself, top and bottom plates, caprocks, formations, faults and other factors can all play a controlling role in the preservation of unconventional natural gas. Poor preservation conditions will lead to the escape of natural gas, which will in turn destroy the gas reservoir. Therefore, scientifically and rationally evaluating the preservation conditions of black rock type unconventional natural gas to determine the favorable areas for the preservation conditions of black rock type unconventional natural gas is of great significance for improving the theoretical understanding of unconventional geology and improving the practical effects of exploration and development.

[0003] At present, the determination of favorable areas for the preservation of black rock type unconventional natural gas mainly involves methods and technologies such as geological analysis, geophysical data analysis, fuzzy evaluation of qualitative parameters, and numerical analysis and evaluation of quantitative parameters. There are also cross-combinations and comprehensive applications of different methods. The existing methods used to determine favorable areas for the preservation of black rock type unconventional natural gas mainly have the following problems: the existing methods do not adequately consider the role of the self-generation and self-storage characteristics of black rock type unconventional natural gas in the preservation conditions, and the contribution of the closure of the reservoir itself to the preservation of natural gas is insufficient. In addition, the existing methods mainly rely on subjective judgment to determine the weights of evaluation parameters, which will lead to low accuracy in the evaluation of the preservation conditions of black rock type unconventional natural gas for the actual situation of the evaluation area, so there are certain limitations in guiding the exploration and development of this type of natural gas. Summary of the invention

[0004] The embodiment of the present invention provides a method and device for determining favorable areas for the preservation of black rock type unconventional natural gas, so as to solve the problems of insufficient understanding of the contribution of the sealing property of the reservoir itself to the preservation of natural gas and low evaluation accuracy in the current determination of favorable areas for the preservation of black rock type unconventional natural gas.

[0005] In a first aspect, an embodiment of the present invention provides a method for determining a favorable area for preservation of unconventional natural gas of black rock series type, comprising:

[0006] Obtaining evaluation parameters of the target black rock series unconventional natural gas in the area to be evaluated; wherein the evaluation parameters include reservoir parameters, top and bottom plate parameters, cap rock parameters, formation parameters and fault parameters;

[0007] Construct corresponding closure indicators according to the evaluation parameters;

[0008] Determine the parameter weight of each closure indicator according to each closure indicator, and determine the comprehensive preservation indicator according to each closure indicator and its corresponding parameter weight;

[0009] Based on comprehensive preservation indicators, determine the target black rock series type unconventional natural gas preservation favorable areas.

[0010] In one possible implementation method, based on comprehensive preservation indicators, the target black rock series type unconventional natural gas preservation favorable area is determined, including:

[0011] The statistical analysis method of comprehensive conservation index of standard area is used to determine the boundary values ​​of comprehensive conservation index corresponding to favorable and relatively favorable areas, and the comprehensive conservation index interval corresponding to favorable area is determined according to the boundary values ​​of comprehensive conservation index corresponding to favorable and relatively favorable areas;

[0012] Calculate the comprehensive preservation index value on any plane within the area to be evaluated;

[0013] If the comprehensive preservation index value on the plane is within the comprehensive preservation index interval corresponding to the favorable zone, it is determined that the preservation conditions of the target black rock series unconventional natural gas on the plane are in the favorable zone.

[0014] In a possible implementation, the method further includes:

[0015] Adopt the statistical analysis method of comprehensive preservation index of standard area to determine the limit values ​​of comprehensive preservation index corresponding to the less favorable and unfavorable areas, and determine the comprehensive preservation index interval corresponding to the more favorable area and the comprehensive preservation index interval corresponding to the less favorable and unfavorable areas according to the limit values ​​of comprehensive preservation index corresponding to the favorable and more favorable areas and the limit values ​​of comprehensive preservation index corresponding to the unfavorable areas;

[0016] If the comprehensive preservation index value on the plane is within the comprehensive preservation index interval corresponding to the more favorable area, it is determined that the target black rock series type unconventional natural gas preservation conditions on the plane are in the more favorable area;

[0017] If the comprehensive preservation index value on the plane is within the comprehensive preservation index interval corresponding to the unfavorable zone, it is determined that the preservation conditions of the target black rock series unconventional natural gas on the plane are in the unfavorable zone.

[0018] In a possible implementation, determining the parameter weight of each closure indicator according to each closure indicator includes:

[0019] Calculate the maximum and minimum values ​​corresponding to each closure index in the area to be evaluated;

[0020] Normalize the closure index values ​​of each evaluation point in the area to be evaluated and their corresponding maximum and minimum values;

[0021] According to the normalized closing index values ​​of each evaluation point, the average value of each closing index value after normalization is calculated;

[0022] For any evaluation point in the area to be evaluated, the variance of each normalized closure index value is calculated according to each normalized closure index value of the evaluation point and the normalized average value corresponding to each normalized closure index value;

[0023] According to the variance of each closure index value of the evaluation point, the subjective weight calculation method and the objective weight calculation method are respectively used to calculate the subjective weight and the objective weight of each closure index value of the evaluation point;

[0024] The parameter weight of each closure index value of the evaluation point is determined according to the subjective weight and the objective weight of each closure index value of the evaluation point.

[0025] In a possible implementation, the comprehensive preservation index, each closure index and their corresponding parameter weights satisfy the following relationship:

[0026] CPI x =w Self SAI Self (x)+w Cap SAI Cap (x)+w Roof-floor SAI Roof-floor (x)+w Fault SAI Fault (x)+w Stratum SAI Stratum (x)

[0027] w Self +w cap +w Roof-floor +w Fault +w Stratum =1

[0028] Among them, CPI x is a comprehensive preservation index; Self is the parameter weight of the reservoir self-sealing index; SAI Self (x) is the reservoir self-sealing index; w Cap is the parameter weight of the caprock sealing index; SAI Cap (x) is the caprock sealing index; wRoof-floor is the parameter weight of the top and bottom plate closure parameter index; SAI Roof-floor (x) is the top and bottom plate sealing parameter index; w Fault is the parameter weight of the fault sealing index; SAI Fault (x) is the fault sealing index; w Stratum is the parameter weight of the formation sealing index; SAI Stratum (x) is the formation sealing index.

[0029] In a possible implementation, corresponding closure indicators are constructed according to the evaluation parameters, including:

[0030] A reservoir self-sealing index is constructed according to reservoir parameters; wherein the reservoir parameters include reservoir water contact angle, reservoir oil contact angle, reservoir pressure, Langmuir pressure under reservoir conditions and reservoir thickness.

[0031] The top and bottom plate sealing index is constructed according to the top and bottom plate parameters; wherein the top and bottom plate parameters include top and bottom thickness, bottom plate thickness, top and bottom porosity, bottom plate porosity, top plate water contact angle, top plate oil contact angle, bottom plate water contact angle and bottom plate oil contact angle;

[0032] Constructing cap rock sealing indexes according to cap rock parameters; wherein the cap rock parameters include cap rock lithology factors, single layer thickness and distance from the reservoir midpoint of each layer in the cap rock statistical section;

[0033] Constructing a formation sealing index based on formation parameters; wherein the formation parameters include the distance between the reservoir and the denudation zone and the formation dip;

[0034] The fault closure index is constructed based on the fault parameters, wherein the fault parameters include the vertical fault distance, fault mud thickness, distance from the fault and fault density.

[0035] In a possible implementation, the reservoir self-sealing index is:

[0036]

[0037] Among them, RW o-Res is the relative wettability of reservoir oil, dimensionless; DFI Res is the reservoir thickness favorableness index, dimensionless; S Res Theoretical gas saturation of the reservoir, in percentage form; α o-Res is the reservoir oil contact angle, in degrees; α w-Res is the reservoir water contact angle, in degrees; P Res is the reservoir pressure, in MPa; P L is the Langmuir pressure under reservoir conditions, in MPa; D Res is the reservoir thickness, in m;

[0038] The top and bottom plate sealing index is:

[0039]

[0040] Among them, I D-Roof-floor is the closure index of the top and bottom plate thickness; RW is the porosity closure index of the roof and floor, dimensionless; W-Roof-floor D is the porosity closure index of the top and bottom plates, dimensionless; Roof is the top and bottom thickness; D Floof is the base plate thickness; is the top and bottom porosity, in percentage form; is the porosity of the bottom plate, in percentage form; α W-Roof is the water contact angle of the top plate; α o-Roof is the top plate oil contact angle; α W-Floof is the water contact angle of the bottom plate; α O-Floof is the contact angle of the bottom plate oil;

[0041] The caprock sealing index is:

[0042]

[0043] Among them, M is the statistical layer segment; k Cap-i is the cap rock lithology factor of the i-th layer in the cap rock statistical interval, dimensionless; ΔH cap-i is the single layer thickness of the i-th layer in the statistical layer section of the caprock, in m; R Cap-i is the distance from the i-th layer in the caprock statistical interval to the midpoint of the reservoir, in meters;

[0044] The formation sealing index is:

[0045]

[0046] Among them, L Stratum is the distance between the reservoir and the denudation zone, in meters; θ is the formation dip, in radians;

[0047] The fault sealing index is:

[0048]

[0049] Among them, γ Fault is the fault distance impact index; SGP Fault is the fault mud ratio; RM Fault is the fault number impact index; N is the number of disconnected mudstone layers; ΔH Mud-i is the vertical thickness of the disconnected mudstone layer i, in m; H Fault is the vertical distance of the fault; S Faultis the distance from the fault, in meters; G is the main fault level in the area to be evaluated; M Fault is the fault density, in units of bars / km 2 .

[0050] In a second aspect, an embodiment of the present invention provides a device for determining a favorable area for preservation of unconventional natural gas of black rock series type, comprising:

[0051] An acquisition module is used to acquire evaluation parameters of the target black rock series unconventional natural gas in the area to be evaluated; wherein the evaluation parameters include reservoir parameters, top and bottom plate parameters, cap rock parameters, formation parameters and fault parameters;

[0052] A construction module, used to construct corresponding closure indicators according to the evaluation parameters;

[0053] A calculation module, used to determine the parameter weight of each closure indicator according to each closure indicator, and determine the comprehensive preservation indicator according to each closure indicator and its corresponding parameter weight;

[0054] The determination module is used to determine the favorable areas for the preservation of target black rock series unconventional natural gas based on comprehensive preservation indicators.

[0055] In a third aspect, an embodiment of the present invention provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the processor implements the steps of the method described in the first aspect or any possible implementation manner of the first aspect.

[0056] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method described in the first aspect or any possible implementation method of the first aspect are implemented.

[0057] The embodiment of the present invention provides a method and device for determining favorable areas for preservation conditions of unconventional natural gas of black rock series. Compared with the traditional method, the embodiment of the present invention analyzes the preservation condition evaluation parameters composed of the reservoir itself and other common factors, thereby improving the pertinence, accuracy and scientific rationality of the evaluation of the preservation conditions of such natural gas; secondly, the corresponding closure indexes are determined according to these evaluation parameters, and the comprehensive preservation index is further determined. These new indexes are constructed by relevant basic geological parameters and other targeted basic parameters, which can achieve the pertinence and comprehensiveness of the determination of favorable areas for preservation conditions of unconventional natural gas of black rock series; and, considering the different influences of different closure indexes, the comprehensive preservation index also includes the parameter weights of each closure index, so that the differences and particularities of the geological conditions related to the preservation of unconventional natural gas of black rock series in different evaluation areas can be fully considered, thereby ensuring the objectivity and rationality of the final results, so as to improve the evaluation accuracy. Finally, the method provided by the embodiment of the present invention can realize the software, automation and intelligence of the entire evaluation process, thereby greatly reducing the labor and human errors. In summary, the embodiments of the present invention can improve the accuracy and efficiency of determining favorable areas for black rock series unconventional natural gas preservation conditions, and make the obtained results more reasonable and objective. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0059] Figure 1 It is a flow chart for realizing a method for determining a favorable area for preservation conditions of black rock series unconventional natural gas provided by an embodiment of the present invention;

[0060] Figure 2 : is a schematic diagram of the structure of a device for determining a favorable area for storage conditions of black rock series unconventional natural gas provided by an embodiment of the present invention;

[0061] Figure 3 is a schematic diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0062] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0063] In order to make the purpose, technical solutions and advantages of the present invention more clear, specific embodiments will be described below in conjunction with the accompanying drawings.

[0064] Figure 1 : is a flowchart of the method for determining favorable areas for preservation conditions of black rock series unconventional natural gas provided by an embodiment of the present invention; Figure 1 As shown, the method includes:

[0065] Step 110: Obtain evaluation parameters of the target black rock series unconventional natural gas in the area to be evaluated; wherein the evaluation parameters include reservoir parameters, top and bottom plate parameters, cap rock parameters, formation parameters and fault parameters.

[0066] In this embodiment, in order to better evaluate the preservation conditions of black rock type unconventional natural gas in the evaluation area, it is necessary to obtain the evaluation parameters of the reservoir itself, top and bottom plates, cap rock, strata and faults of the target black rock type unconventional natural gas at the typical evaluation points in the evaluation area. The selection of evaluation points should fully consider factors such as stratum distribution, sedimentary environment, structural geological units, hydrogeological conditions, magmatic activity, stratum erosion and exposure, landforms and artificial buildings. At the same time, the selection of data should consider the plane distribution and try to achieve uniform distribution. Among them, the evaluation parameters can be obtained by the following acquisition method:

[0067] Reservoir parameters mainly include reservoir water contact angle, reservoir oil contact angle, reservoir pressure, Langmuir pressure under reservoir conditions (i.e., Langmuir pressure, a parameter of the reservoir Langmuir adsorption model), and reservoir thickness. Reservoir thickness can be obtained through analysis of drilling logging data or geological outcrop data; Langmuir pressure, a parameter of the reservoir Langmuir adsorption model, can be obtained through isothermal adsorption tests under reservoir conditions; reservoir pressure can be obtained through well test data; and reservoir water contact angle and oil contact angle can be obtained through contact angle tests of rock samples.

[0068] The top and bottom plate parameters can mainly include top and bottom thickness, bottom plate thickness, top and bottom porosity, bottom plate porosity, top plate water contact angle, top plate oil contact angle, bottom plate water contact angle and bottom plate oil contact angle. The top and bottom thickness and bottom plate thickness can be obtained through the analysis of drilling logging data or geological outcrop data; the top and bottom porosity and bottom plate porosity can be obtained through rock porosity analysis experiments; the top plate water contact angle, top plate oil contact angle, bottom plate water contact angle and bottom plate oil contact angle can be obtained through rock sample contact angle tests.

[0069] The caprock parameters mainly include the caprock lithology factor, single layer thickness and distance from the midpoint of the reservoir of each layer in the caprock statistical interval. The lithology and corresponding thickness of the caprock are mainly obtained through drilling, logging and mud logging data. Therefore, in order to meet the needs of subsequent analysis, the lithology and single layer thickness data within 100m of the caprock thickness at a single evaluation point should be mastered.

[0070] The formation parameters mainly include the distance between the reservoir and the outcrop / erosion area and the formation dip. The distance between the reservoir and the outcrop / erosion area and the formation dip can be determined through geological survey results and drilling data.

[0071] Fault parameters mainly include vertical fault throw, fault mud thickness, distance from the fault and fault density. These parameters can be determined comprehensively through geological survey results, earthquake-related geophysical data and drilling data.

[0072] Step 120: Construct corresponding closure indicators according to the evaluation parameters.

[0073] In this embodiment, since the current stage mainly evaluates the preservation conditions based on basic index parameters, and rarely involves comprehensive evaluation parameters, this will lead to too many parameters involved in the evaluation of unconventional natural gas preservation conditions, and it is difficult to determine the relative importance of the parameters. In addition, since the current methods do not adequately consider the role of the self-generation and self-storage characteristics of black rock type unconventional natural gas in the preservation conditions, and the contribution of the reservoir's own sealing to natural gas preservation is insufficiently understood, this embodiment constructs a reservoir self-sealing index based on reservoir parameters; constructs a top and bottom plate sealing index based on top and bottom plate parameters; constructs a cap rock sealing index based on cap rock parameters; constructs a formation sealing index based on formation parameters; and constructs a fault sealing index based on fault parameters.

[0074] Specifically, in order to evaluate the self-sealing ability of the reservoir, the present invention calculates the relative wettability of the reservoir oil through the water contact angle and the oil contact angle of the reservoir, calculates the theoretical gas saturation of the reservoir through the Langmuir adsorption model parameters of the reservoir, the Langmuir pressure and the reservoir pressure, and calculates the reservoir thickness favorable index through the reservoir thickness. Higher relative wettability of the reservoir oil, higher theoretical gas saturation of the reservoir, and higher favorable index of reservoir thickness correspond to better self-sealing ability. Further, a reservoir self-sealing index is constructed through three index parameters, namely, the relative wettability of the reservoir oil, the theoretical gas saturation of the reservoir, and the favorable index of reservoir thickness. The larger the value of the reservoir self-sealing index, the stronger the reservoir self-sealing ability.

[0075] Accordingly, the reservoir self-sealing index can be:

[0076]

[0077] Among them, SAI Self RW is the reservoir self-sealing index; O-Res is the relative wettability of reservoir oil, dimensionless; DFI Res is the reservoir thickness favorableness index, dimensionless; S Res Theoretical gas saturation of the reservoir, in percentage form; α O-Res is the reservoir oil contact angle, in degrees; α W-Res is the reservoir water contact angle, in degrees; P Res is the reservoir pressure, in MPa; P L is the Langmuir pressure under reservoir conditions, in MPa; D Res is the reservoir thickness, in m.

[0078] In order to evaluate the sealing ability of the top and bottom plates, the present embodiment calculates the top and bottom plate thickness sealing index by the top and bottom thickness and the bottom plate thickness, calculates the top and bottom plate porosity sealing index by the top and bottom porosity and the bottom plate porosity, and calculates the top and bottom plate porosity sealing index by the top plate water contact angle, the top plate oil contact angle, the bottom plate water contact angle and the bottom plate oil contact angle. Higher top and bottom plate thickness sealing index, top and bottom plate porosity sealing index and top and bottom plate porosity sealing index correspond to better self-sealing ability. Further, the top and bottom plate sealing index is constructed by three index parameters: top and bottom plate thickness sealing index, top and bottom plate porosity sealing index and top and bottom plate porosity sealing index. The larger the top and bottom plate sealing index value, the stronger the top and bottom plate sealing ability.

[0079] Accordingly, the top and bottom plate sealing index can be:

[0080]

[0081] Among them, SAI Roof-floor It is the index of the sealing performance of the top and bottom plates; I D-Roof-flooris the closure index of the top and bottom plate thickness; RW is the porosity closure index of the roof and floor, dimensionless; w-Roof-floor D is the porosity closure index of the top and bottom plates, dimensionless; Roof is the top and bottom thickness; D Floof is the base plate thickness; is the top and bottom porosity, in percentage form; is the porosity of the bottom plate, in percentage form; α w-Roof is the water contact angle of the top plate; α O-Roof is the top plate oil contact angle; α w-Floof is the water contact angle of the bottom plate; α O-Floof is the contact angle of the bottom plate oil.

[0082] In order to evaluate the sealing capacity of the caprock, this embodiment can construct a caprock sealing index by the lithology and corresponding thickness of the rock formation within 100 m above the reservoir. The larger the caprock sealing index value, the stronger the caprock sealing capacity.

[0083] Accordingly, the caprock sealing index can be:

[0084]

[0085] Among them, M is the statistical layer segment; k Cap-i is the cap rock lithology factor of the i-th layer in the cap rock statistical interval, dimensionless; ΔH cap-i is the single layer thickness of the i-th layer in the statistical layer section of the caprock, in m; R Cap-i It is the distance from the i-th layer in the caprock statistical interval to the midpoint of the reservoir, in meters.

[0086] Among them, the cap rock lithology factor k Cap-i The assignment criteria for are shown in Table 1.

[0087] Table 1 Caprock lithology factor k Cap-i Assignment criteria

[0088]

[0089] In Table 1, if the cap rock is gypsum salt rock or mudstone, then the corresponding cap rock lithology factor k Cap-i is 1; if the cap rock is silty mudstone or sandy mudstone, then the corresponding cap rock lithology factor k Cap-i is 0.6; if the cap rock is muddy siltstone or dense carbonate rock, then the corresponding cap rock lithology factor k Cap-i is 0.2.

[0090] In order to evaluate the sealing capacity of the formation, this embodiment constructs a formation sealing index by the distance between the reservoir and the outcrop / erosion zone and the formation dip angle. The larger the formation sealing index value, the stronger the fault sealing capacity.

[0091] Accordingly, the formation sealing index can be:

[0092]

[0093] Among them, SAI Stratum L is the formation sealing index; Stratum is the distance between the reservoir and the denudation zone, in meters; θ is the formation dip, in radians.

[0094] In order to evaluate the fault sealing capacity, this embodiment calculates the fault mud ratio by the vertical fault distance and the fault mud thickness, calculates the fault distance influence index by the distance from the fault and the fault level G, and calculates the fault number influence index by the fault density. Higher fault mud ratios, fault distance influence indexes, and fault number influence indexes correspond to better self-sealing capacity. Further, the fault sealing index is constructed by the three index parameters of the fault mud ratio, fault distance influence index, and fault number influence index. The larger the fault sealing index value, the stronger the fault sealing capacity.

[0095] Accordingly, the fault sealing index can be:

[0096]

[0097] Among them, SAI Fault is the fault sealing index; γ Fault is the fault distance impact index; SGP Fault is the fault mud ratio; RM Fault is the fault number impact index; N is the number of disconnected mudstone layers; ΔH Mud-i is the vertical thickness of the disconnected mudstone layer i, in m; H Fault is the vertical distance of the fault; S Fault is the distance from the fault, in meters; G is the level of the main fault in the area to be evaluated, generally divided into 1 to 4 levels; M Fault is the fault density, in units of bars / km 2 .

[0098] Step 130: Determine the parameter weight of each closure indicator according to each closure indicator, and determine the comprehensive preservation indicator according to each closure indicator and its corresponding parameter weight.

[0099] In this embodiment, since the determination of parameter weights at this stage mainly relies on subjective judgment, the quantitative actual data of the area to be evaluated are not used to determine the parameter weights, which will lead to a lack of objective evaluation of the actual conditions of the area to be evaluated for the preservation conditions of black rock series unconventional natural gas, so there are certain limitations in guiding the exploration and development of this type of natural gas; in addition, the current evaluation method for the preservation conditions of unconventional natural gas contains a certain number of qualitative parameters, which makes it difficult to make a completely quantitative objective evaluation, and may even make it impossible to quantitatively present the evaluation results.

[0100] In order to solve the problem of lack of objectivity in determining parameter weights, in an optional embodiment, determining the parameter weights of each closure index according to each closure index may include:

[0101] Calculate the maximum and minimum values ​​corresponding to each closure index in the area to be evaluated.

[0102] The closure index values ​​of each evaluation point in the area to be evaluated and their corresponding maximum and minimum values ​​are normalized.

[0103] According to the normalized closure index values ​​of each evaluation point, the average value of each closure index value after normalization is calculated.

[0104] For any evaluation point in the area to be evaluated, the variance of each normalized closure index value is calculated according to each normalized closure index value of the evaluation point and the normalized average value corresponding to each normalized closure index value.

[0105] According to the variance of each closure index value of the evaluation point, the subjective weight calculation method and the objective weight calculation method are respectively used to calculate the subjective weight and the objective weight of each closure index value of the evaluation point.

[0106] The parameter weight of each closure index value of the evaluation point is determined according to the subjective weight and the objective weight of each closure index value of the evaluation point.

[0107] In this embodiment, the five closure indices corresponding to each evaluation point in the area to be evaluated are calculated using the calculation formulas for the closure indicators given in the above-mentioned related embodiments. For each closure indicator, the maximum value calculated in the area to be evaluated is used as the maximum value corresponding to the closure indicator value, and the minimum value calculated in the area to be evaluated is used as the minimum value corresponding to the closure indicator value.

[0108] Then, the closure index values ​​of each evaluation point in the area to be evaluated and their corresponding maximum and minimum values ​​are normalized. Taking any evaluation point as an example, the normalization can be performed using the following formula:

[0109]

[0110] Among them, SAI Self (x) is the normalized reservoir self-sealing index value of the evaluation point; SAI Self-x SAI is the reservoir self-sealing index value of the evaluation point; Self-max and SAI Self-min Respectively represent the maximum and minimum values ​​of the reservoir self-sealing index in the area to be evaluated, dimensionless; SAI Cap (x) is the caprock sealing index value after normalization at the evaluation point; SAI Cap-x SAI is the caprock sealing index value of the evaluation point; Cap-max and SAI Cap-min Respectively represent the maximum and minimum values ​​of the caprock sealing index in the area to be evaluated, dimensionless; SAI Roof-floor (x) is the normalized top and bottom plate sealing index value of the evaluation point; SAI Roof-flo0r-x SAI is the sealing index value of the roof and floor of the evaluation point; Roof-floor-max and SAI Roof-floor-min Respectively represent the maximum and minimum values ​​of the roof and floor sealing index in the area to be evaluated, dimensionless; SAI Fault (x) is the normalized fault sealing index value of the evaluation point; SAI Fault-x is the fault sealing index value of the evaluation point; v Fault-max and SAI Fault-min Respectively represent the maximum and minimum values ​​of the fault sealing index in the area to be evaluated, dimensionless; SAI Stratum (x) is the normalized formation sealing index value of the evaluation point; SAI Stratum-x SAI is the formation sealing index value of the evaluation point; Stratum-max and SAI Stratum-min They respectively represent the maximum and minimum values ​​of the formation sealing index in the area to be evaluated, and are dimensionless.

[0111] After obtaining the normalized closure index values ​​corresponding to the evaluation points in the area to be evaluated, the average value is calculated to obtain the average value of the normalized closure index values.

[0112] Then, let

[0113]

[0114] in,

[0115] In the formula, is the variance of the reservoir self-sealing index value; is the variance of the caprock sealing index value; is the variance of the top and bottom plate closure index value; is the variance of the fault sealing index value; is the variance of the formation sealing index value; is the average value of the reservoir self-sealing index after normalization; is the average value of the caprock sealing index after normalization; is the average value of the top and bottom plate sealing index after normalization; is the average value of the fault sealing index after normalization; is the average value of the formation sealing index after normalization, and n represents the number of evaluation points in the area to be evaluated.

[0116] Using variance contribution rate as the objective weight of different indicators:

[0117]

[0118] Among them, w Self-1 is the objective weight of the reservoir self-sealing index; w Cap-1 is the objective weight of the caprock sealing index; w Roof-floor-1 is the objective weight of the top and bottom plate closure index; w Fault-1 is the objective weight of the fault sealing index; w Stratum-1 It is the objective weight of the formation sealing index.

[0119] Subjective weights can be determined through methods such as Analytic Hierarchy Process (AHP) and expert surveys. Specifically:

[0120] ∑w1w2=w Self-1 w self-2 +w cap-1 w cap-2 +w Roof-floor-1 w Roof-floor-2 +w Fault-1 w Fault-2 +w Strarum- 1w Stratum-2

[0121] Among them, ∑w1w2 represents the intermediate parameter; w Self-2 is the subjective weight of the reservoir self-sealing index; w Cap-2 is the subjective weight of the caprock sealing index; w Roof-floor-2 is the subjective weight of the top and bottom plate closure index; w Fault-2 is the subjective weight of the fault closure index; w Stratum-2 is the subjective weight of the formation sealing index. Each subjective weight value can be set according to actual needs.

[0122] The subjective weight and objective weight of each closure index value obtained are used to determine the final parameter weight of each closure index value of the evaluation point by using the subjective and objective comprehensive method or the combined weighting method. That is:

[0123]

[0124] Among them, w Self is the parameter weight of the reservoir self-sealing index; w Cap is the parameter weight of the caprock sealing index; w Roof-floor is the parameter weight of the top and bottom plate closure index; w Fault is the parameter weight of the fault sealing index; w Stratum is the parameter weight of the formation sealing index.

[0125] In order to solve the problem that the current evaluation method for the preservation conditions of unconventional natural gas contains a certain number of qualitative parameters, which makes it difficult to conduct a completely quantitative and objective evaluation, and may even cause the evaluation results to be unable to be presented quantitatively, the sealing indexes and their corresponding parameter weights in the embodiment of the present invention construct a new comprehensive preservation index. Specifically, the comprehensive preservation index can be characterized as:

[0126] CPI x =w Self SAI Self (x)+w Cap SAI Cap (x)+w Roof-floor SAI Roof-floor (x)+w Fault SAI Fault (x)+w Stratum SAI Stratum (x)

[0127] w Self +w Cap +w Roof-floor +w Fault +w Stratum =1

[0128] Among them, CPI x is a comprehensive preservation index; Self is the parameter weight of the reservoir self-sealing index; SAI Self (x) is the reservoir self-sealing index; w Cap is the parameter weight of the caprock sealing index; SAI Cap (x) is the caprock sealing index; w Roof-floor is the parameter weight of the top and bottom plate closure parameter index; SAI Roof-floor (x) is the top and bottom plate sealing parameter index; w Fault is the parameter weight of the fault sealing index; SAIFault (x) is the fault sealing index; w Stratum is the parameter weight of the formation sealing index; SAI Stratum (x) is the formation sealing index.

[0129] Therefore, CPI x The value range is [0, 1].

[0130] In particular, when the weights of the closure indicators are close, we have:

[0131]

[0132] Step 140: Determine the target black rock series type unconventional natural gas preservation favorable area based on the comprehensive preservation index.

[0133] In this embodiment, in order to grade and evaluate the preservation conditions of black rock series unconventional natural gas, it is necessary to determine the comprehensive preservation index limit values ​​of favorable and relatively favorable preservation conditions, and the comprehensive preservation index limit values ​​of relatively favorable and unfavorable preservation conditions. And according to the calculated comprehensive preservation index of the evaluation point, it is determined whether the preservation conditions of the evaluation point are favorable areas.

[0134] Accordingly, based on the comprehensive preservation indicators, the favorable areas for the preservation of target black rock series unconventional natural gas can be determined, which may include:

[0135] The statistical analysis method of comprehensive preservation indicators in standard areas is used to determine the limit values ​​of comprehensive preservation indicators corresponding to favorable and relatively favorable areas, and the comprehensive preservation indicator interval corresponding to favorable areas is determined based on the limit values ​​of comprehensive preservation indicators corresponding to relatively unfavorable and unfavorable areas.

[0136] Calculate the comprehensive preservation index value on any plane in the area to be evaluated.

[0137] If the comprehensive preservation index value on the plane is within the comprehensive preservation index interval corresponding to the favorable zone, it is determined that the preservation conditions of the target black rock series unconventional natural gas on the plane are in the favorable zone.

[0138] In some optional embodiments, the method may further include:

[0139] The statistical analysis method of comprehensive preservation indicators in standard areas is used to determine the limit values ​​of comprehensive preservation indicators corresponding to the less favorable and unfavorable areas. Based on the limit values ​​of comprehensive preservation indicators corresponding to the less favorable and unfavorable areas and the limit values ​​of comprehensive preservation indicators corresponding to the less favorable and unfavorable areas, the comprehensive preservation indicator interval corresponding to the more favorable area and the comprehensive preservation indicator interval corresponding to the unfavorable area are determined.

[0140] If the comprehensive preservation index value on the plane is within the comprehensive preservation index interval corresponding to the more favorable area, it is determined that the preservation conditions of the target black rock series unconventional natural gas on the plane are in the more favorable area.

[0141] If the comprehensive preservation index value on the plane is within the comprehensive preservation index interval corresponding to the unfavorable zone, it is determined that the preservation conditions of the target black rock series unconventional natural gas on the plane are in the unfavorable zone.

[0142] In this embodiment, the comprehensive conservation index limit value CPI corresponding to the favorable and relatively favorable areas is RF-F The CPI threshold value of the comprehensive preservation index corresponding to the relatively unfavorable and unfavorable areas DF-RF This can be determined through statistical analysis of standard areas / calibration areas. The geological data related to the preservation conditions in the standard areas / calibration areas of black rock type unconventional natural gas preservation conditions are rich, the previous preservation conditions research and understanding are high, and the favorableness of the black rock type unconventional natural gas preservation conditions in these standard areas / calibration areas (favorable, relatively favorable or unfavorable) has been clearly concluded. By analyzing the comprehensive preservation index CPI of different data points in such standard areas / calibration areas x The favorable, relatively favorable and unfavorable categories are classified and counted, and then the CPI threshold values ​​corresponding to the favorable and relatively favorable areas can be determined through probability statistical analysis. RF-F The CPI threshold value of the comprehensive preservation index corresponding to the relatively unfavorable and unfavorable areas DF-RF .

[0143] In determining the CPI RF-F and CPI DF-RF Afterwards, the contour line method was used to determine the comprehensive preservation index interval corresponding to the favorable area, the comprehensive preservation index interval corresponding to the relatively favorable area, and the comprehensive preservation index interval corresponding to the unfavorable area. Among them, the comprehensive preservation index interval corresponding to the area with favorable preservation conditions is [CPI RF-F , 1], the comprehensive preservation index range corresponding to the area with favorable preservation conditions is [CPI RF-F , CPI DF-RF ), the comprehensive preservation index range corresponding to the unfavorable preservation condition area is [0, CPI DF-RF ), that is, when CPI x ∈[CPI RF-F , 1], the preservation condition on the plane is in the favorable zone, when CPI x ∈[CPI RF-F , CPI DF-RF ), the preservation conditions on the plane are in a more favorable area. When CPI x ∈[0, CPI DF-RF ), the preservation conditions on this plane are in the unfavorable zone.

[0144] In particular, when the distribution of the values ​​of the comprehensive preservation indexes of favorable, relatively favorable and unfavorable preservation conditions is similar, the favorable preservation conditions area of ​​the target black rock series type unconventional natural gas can be determined based on the comprehensive preservation index, which may include:

[0145] Calculate the maximum and minimum comprehensive conservation index values ​​in the area to be evaluated.

[0146] Based on the maximum and minimum comprehensive preservation indices, the favorable areas for the preservation of target black rock type unconventional natural gas are determined.

[0147] In this embodiment, according to the comprehensive preservation index calculation formula given in step 130, the comprehensive preservation index value of each evaluation point in the area to be evaluated is calculated, and the maximum comprehensive preservation index value and the minimum comprehensive preservation index value in the area to be evaluated are determined based on the comprehensive preservation index value of each evaluation point.

[0148] Accordingly, in an optional embodiment, determining the target black rock series type unconventional natural gas preservation condition favorable area according to the maximum comprehensive preservation index value and the minimum comprehensive preservation index value may include:

[0149] According to the maximum comprehensive preservation index value and the minimum comprehensive preservation index value, the comprehensive preservation index limit values ​​corresponding to the favorable and relatively favorable areas, and the comprehensive preservation index limit values ​​corresponding to the relatively unfavorable and unfavorable areas are determined; and according to the comprehensive preservation index limit values ​​corresponding to the favorable areas and the comprehensive preservation index limit values ​​corresponding to the unfavorable areas, the comprehensive preservation index interval corresponding to the favorable areas, the comprehensive preservation index interval corresponding to the relatively favorable areas, and the comprehensive preservation index interval corresponding to the unfavorable areas are determined.

[0150] Calculate the comprehensive preservation index value of any evaluation point in the area to be evaluated.

[0151] If the comprehensive preservation index value of the evaluation point is within the comprehensive preservation index interval corresponding to the favorable zone, it is determined that the target black rock series unconventional natural gas preservation conditions of the evaluation point are in the favorable zone.

[0152] If the comprehensive preservation index value of the evaluation point is within the comprehensive preservation index interval corresponding to the more favorable area, it is determined that the target black rock series unconventional natural gas preservation conditions of the evaluation point are in the more favorable area.

[0153] If the comprehensive preservation index value of the evaluation point is within the comprehensive preservation index interval corresponding to the unfavorable zone, it is determined that the target black rock series unconventional natural gas preservation conditions of the evaluation point are in the unfavorable zone.

[0154] The limit values ​​of comprehensive preservation indicators corresponding to favorable and relatively favorable areas can be expressed as:

[0155] CPI RF-F =CPI x-min +(CPIx-max -CPI x-min ) / 3

[0156] The limit values ​​of comprehensive preservation indicators corresponding to the relatively unfavorable and unfavorable areas can be expressed as:

[0157] CPI DF-RF =CPI x-min +2(CPI x-max -CPI x-min ) / 3

[0158] Accordingly, for the evaluation of the preservation conditions of black rock series unconventional natural gas at a certain evaluation point in the evaluation area, the comprehensive preservation index range corresponding to the favorable preservation condition area is [CPI RF-F , 1], the comprehensive preservation index range corresponding to the area with favorable preservation conditions is [CPI RF-F , CPI DF-RF ), the comprehensive preservation index range corresponding to the unfavorable preservation condition area is [0, CPI DF-RF ), that is, when CPI x ∈[CPI RF-F , 1], the preservation condition of the evaluation point is in the favorable area, when CPI x ∈[CPI RF-F , CPI DF-RF ), the preservation condition of the evaluation point is in a more favorable area, when CPI x ∈[0, CPI DF-RF ), the preservation condition of the evaluation point is in the unfavorable zone.

[0159] In summary, compared with the traditional method, the embodiment of the present invention has the following advantages:

[0160] (1) The embodiment of the present invention is an evaluation method for the preservation conditions of black rock type unconventional natural gas. In the process of proposing the method and technology, the characteristics of self-generation and self-storage of this type of natural gas resources and the integration of source and reservoir are fully considered. Different from other types of natural gas formed by secondary migration outside the source, the method and technology proposes a preservation condition evaluation parameter composed of the reservoir itself and other common factors based on the particularity of the accumulation of black rock type unconventional natural gas, thereby improving the pertinence, accuracy and scientific rationality of the evaluation of the preservation conditions of this type of natural gas.

[0161] (2) The embodiment of the present invention innovatively proposes a reservoir self-sealing index SAI self , Caprock Sealing Index SAI Cap , Top and bottom plate closure index SAI Roof-floor , Fault Sealing Index SAI Fault and formation sealing index SAI StratumFive new comprehensive evaluation parameters are proposed, and the comprehensive preservation index CPIx of the x-th evaluation point is further constructed. These newly proposed index parameters are constructed by relevant basic geological parameters and other targeted basic parameters, which can achieve the targeted and comprehensive evaluation of the preservation conditions of unconventional natural gas in black rock series.

[0162] (3) The method for evaluating the preservation conditions of black rock type unconventional natural gas proposed in the embodiment of the present invention takes into account the differential effects of different indicator parameters, and the determination of the weights thereof is derived from the actual data of these indicators. In this way, the differences and particularities of the geological conditions related to the preservation of black rock type unconventional natural gas in different evaluation areas can be fully considered, thereby ensuring the objectivity and rationality of the preservation condition evaluation results.

[0163] (4) The black rock type unconventional natural gas preservation condition evaluation index parameters and evaluation results involved in the embodiments of the present invention can be quantified, which is not only conducive to providing quantitative index parameters and criteria for determining helium favorable areas, but also can realize the software, automation and intelligence of the entire evaluation process, thereby greatly reducing the labor and human errors.

[0164] (5) The technical method proposed in the embodiment of the present invention can not only directly evaluate the preservation conditions of black rock type unconventional natural gas, but also lay a good foundation for the optimization of favorable areas for such unconventional natural gas. The preservation condition evaluation results obtained based on the embodiment of the present invention can help to form a more scientific and reasonable understanding of the determination of favorable areas, thereby providing a scientific basis for subsequent exploration and development deployment.

[0165] (6) The method for evaluating the preservation conditions of black rock type unconventional natural gas proposed in the embodiment of the present invention is also inspiring and instructive for the evaluation of the preservation conditions of other types of unconventional natural gas (such as tight sandstone gas). It is also helpful for the systematic research, overall understanding and simultaneous exploration and development of different types of natural gas (including coalbed methane, shale gas, tight carbonate gas, etc.), and can also provide a certain basis for the formulation of relevant unconventional natural gas strategies and strategic planning.

[0166] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0167] The following is an embodiment of the device of the present invention. For details not described in detail therein, reference may be made to the corresponding method embodiment described above.

[0168] Figure 2The schematic diagram of the structure of the device for determining favorable areas of black rock type unconventional natural gas preservation conditions provided by an embodiment of the present invention is shown. For the sake of convenience, only the parts related to the embodiment of the present invention are shown, which are described in detail as follows:

[0169] like Figure 2 As shown, the device 2 for determining favorable areas for storage conditions of black rock series unconventional natural gas includes:

[0170] The acquisition module 21 is used to acquire the evaluation parameters of the target black rock series unconventional natural gas in the area to be evaluated; wherein the evaluation parameters include reservoir parameters, top and bottom plate parameters, cap rock parameters, formation parameters and fault parameters;

[0171] A construction module 22, used to construct corresponding closure indicators according to the evaluation parameters;

[0172] A calculation module 23, for determining a parameter weight of each closure indicator according to each closure indicator, and determining a comprehensive preservation indicator according to each closure indicator and its corresponding parameter weight;

[0173] The determination module 24 is used to determine the favorable area for the preservation of target black rock series unconventional natural gas based on the comprehensive preservation index.

[0174] In a possible implementation, the determination module 24 is specifically configured to:

[0175] The statistical analysis method of standard area is used to determine the boundary values ​​of comprehensive preservation indexes corresponding to favorable and relatively favorable areas, and the comprehensive preservation index interval corresponding to the favorable area is determined based on the boundary values ​​of comprehensive preservation indexes corresponding to the favorable area;

[0176] Calculate the comprehensive preservation index value on any plane within the area to be evaluated;

[0177] If the comprehensive preservation index value on the plane is within the comprehensive preservation index interval corresponding to the favorable zone, it is determined that the preservation conditions of the target black rock series unconventional natural gas on the plane are in the favorable zone.

[0178] In a possible implementation, the determination module 24 is further configured to:

[0179] Adopt the statistical analysis method of standard area to determine the limit values ​​of comprehensive preservation index corresponding to the less favorable and unfavorable areas, and determine the comprehensive preservation index interval corresponding to the more favorable area and the comprehensive preservation index interval corresponding to the unfavorable area based on the limit values ​​of comprehensive preservation index corresponding to the favorable area and the limit values ​​of comprehensive preservation index corresponding to the unfavorable area;

[0180] If the comprehensive preservation index value on the plane is within the comprehensive preservation index interval corresponding to the more favorable area, it is determined that the target black rock series type unconventional natural gas preservation conditions on the plane are in the more favorable area;

[0181] If the comprehensive preservation index value on the plane is within the comprehensive preservation index interval corresponding to the unfavorable zone, it is determined that the preservation conditions of the target black rock series unconventional natural gas on the plane are in the unfavorable zone.

[0182] In a possible implementation, the calculation module 23 is specifically configured to:

[0183] Calculate the maximum and minimum values ​​corresponding to each closure index in the area to be evaluated;

[0184] Normalize the closure index values ​​of each evaluation point in the area to be evaluated and their corresponding maximum and minimum values;

[0185] According to the normalized closing index values ​​of each evaluation point, the average value of each closing index value after normalization is calculated;

[0186] For any evaluation point in the area to be evaluated, the variance of each normalized closure index value is calculated according to each normalized closure index value of the evaluation node and the normalized average value corresponding to each normalized closure index value;

[0187] According to the variance of each closure index value of the price node, the subjective weight calculation method and the objective weight calculation method are used to calculate the subjective weight and the objective weight of each closure index value of the evaluation point respectively;

[0188] The parameter weight of each closure index value of the evaluation point is determined according to the subjective weight and the objective weight of each closure index value of the evaluation point.

[0189] In a possible implementation, the construction module 22 is specifically used to:

[0190] A reservoir self-sealing index is constructed according to reservoir parameters; wherein the reservoir parameters include reservoir water contact angle, reservoir oil contact angle, reservoir pressure, Langmuir pressure under reservoir conditions and reservoir thickness.

[0191] The top and bottom plate sealing index is constructed according to the top and bottom plate parameters; wherein the top and bottom plate parameters include top and bottom thickness, bottom plate thickness, top and bottom porosity, bottom plate porosity, top plate water contact angle, top plate oil contact angle, bottom plate water contact angle and bottom plate oil contact angle;

[0192] Constructing cap rock sealing indexes according to cap rock parameters; wherein the cap rock parameters include cap rock lithology factors, single layer thickness and distance from the reservoir midpoint of each layer in the cap rock statistical section;

[0193] Constructing a formation sealing index based on formation parameters; wherein the formation parameters include the distance between the reservoir and the denudation zone and the formation dip;

[0194] The fault closure index is constructed based on the fault parameters, wherein the fault parameters include the vertical fault distance, fault mud thickness, distance from the fault and fault density.

[0195] Figure 3 Schematic diagram of an electronic device provided by an embodiment of the present invention. Figure 3 As shown, the electronic device 3 of this embodiment includes: a processor 30, a memory 31, and a computer program 32 stored in the memory 31 and executable on the processor 30. When the processor 30 executes the computer program 32, the steps in the above-mentioned method for determining favorable areas for preservation conditions of unconventional natural gas of black rock series are implemented, such as Figure 1 Alternatively, when the processor 30 executes the computer program 32, the functions of each module / unit in the above-mentioned device embodiments are realized, for example Figure 2 Functions of each module / are shown.

[0196] Exemplarily, the computer program 32 may be divided into one or more modules / units, which are stored in the memory 31 and executed by the processor 30 to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of implementing specific functions, which are used to describe the execution process of the computer program 32 in the electronic device 3. For example, the computer program 32 may be divided into Figure 2 The modules / units shown.

[0197] The electronic device 3 may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The electronic device 3 may include, but is not limited to, a processor 30 and a memory 31. Those skilled in the art will appreciate that Figure 3 It is only an example of the electronic device 3 and does not constitute a limitation of the electronic device 3. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the electronic device may also include input and output devices, network access devices, buses, etc.

[0198] The processor 30 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0199] The memory 31 may be an internal storage unit of the electronic device 3, such as a hard disk or memory of the electronic device 3. The memory 31 may also be an external storage device of the electronic device 3, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the electronic device 3. Further, the memory 31 may also include both an internal storage unit and an external storage device of the electronic device 3. The memory 31 is used to store the computer program and other programs and data required by the electronic device. The memory 31 may also be used to temporarily store data that has been output or is to be output.

[0200] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0201] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0202] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0203] In the embodiments provided by the present invention, it should be understood that the disclosed devices / electronic devices and methods can be implemented in other ways. For example, the device / electronic device embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0204] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0205] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0206] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of the above-mentioned black rock system type unconventional natural gas preservation condition favorable area determination method embodiment can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device that can carry the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium.

[0207] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A method for determining favorable areas for the preservation of unconventional natural gas of black rock series, characterized in that: include: Obtaining evaluation parameters of the target black rock series unconventional natural gas in the area to be evaluated; wherein the evaluation parameters include reservoir parameters, top and bottom plate parameters, cap rock parameters, formation parameters and fault parameters; Constructing corresponding closure indicators according to the evaluation parameters; Determining parameter weights of each closure indicator according to each closure indicator, and determining a comprehensive preservation indicator according to each closure indicator and its corresponding parameter weight; According to the comprehensive preservation index, determine the target black rock series type unconventional natural gas preservation condition favorable area; The corresponding closure indicators are constructed according to the evaluation parameters, including: Constructing a reservoir self-sealing index according to the reservoir parameters; wherein the reservoir parameters include a reservoir water contact angle, a reservoir oil contact angle, a reservoir pressure, a Langmuir pressure under reservoir conditions, and a reservoir thickness; Constructing the top and bottom plate sealing index according to the top and bottom plate parameters; wherein the top and bottom plate parameters include top and bottom thickness, bottom plate thickness, top and bottom porosity, bottom plate porosity, top plate water contact angle, top plate oil contact angle, bottom plate water contact angle and bottom plate oil contact angle; Constructing a cap rock sealing index according to the cap rock parameters; wherein the cap rock parameters include cap rock lithology factors, single layer thickness and distance from the midpoint of the reservoir for each layer in the cap rock statistical layer section; Constructing a formation sealing index according to the formation parameters; wherein the formation parameters include the distance between the reservoir and the denudation zone and the formation dip angle; Constructing a fault sealing index according to the fault parameters; wherein the fault parameters include a vertical fault distance, a fault mud thickness, a distance from the fault, and a fault density; The reservoir self-sealing index is: in, is the relative wettability of the reservoir oil, dimensionless; is the reservoir thickness favorableness index, dimensionless; is the theoretical gas saturation of the reservoir, in percentage form; is the reservoir oil contact angle, in degrees; is the reservoir water contact angle, in degrees; is the reservoir pressure, in MPa; is the Langmuir pressure under reservoir conditions, in MPa; is the reservoir thickness, in m; The top and bottom plate sealing index is: in, is the closure index of the top and bottom plate thickness; is the porosity closure index of the roof and floor plates, dimensionless; is the porosity closure index of the roof and floor plates, dimensionless; is the top and bottom thickness; is the base plate thickness; is the top and bottom porosity, in percentage form; is the porosity of the base plate, in percentage form; is the water contact angle of the top plate; is the top plate oil contact angle; is the water contact angle of the bottom plate; is the contact angle of the bottom plate oil; The capping layer sealing index is: in, M The total number of layers in the cover layer section is counted; The first i The cap rock lithology factor of the layer, dimensionless; The first i The single layer thickness of the layer, in m; The first i The distance of the layer from the midpoint of the reservoir, in m; The formation sealing index is: in, is the distance between the reservoir and the denudation zone, in m; is the formation dip angle, in radians; The fault sealing index is: in, is the fault distance impact index; is the fault gouge ratio; is the fault quantity impact index; N is the number of disconnected mudstone layers; For the disconnected i The vertical thickness of the mudstone layer, in m; is the vertical throw of the fault; is the distance from the fault, in m; is the level of the main faults in the area to be evaluated; is the fault density, in units of bars / km 2 ; Determining the target black rock type unconventional natural gas preservation favorable area based on the comprehensive preservation index includes: Using the statistical analysis method of comprehensive conservation indexes of standard areas, determine the boundary values ​​of comprehensive conservation indexes corresponding to favorable and relatively favorable areas, and determine the comprehensive conservation index interval corresponding to the favorable area based on the boundary values ​​of comprehensive conservation indexes corresponding to the favorable and relatively favorable areas; Calculating a comprehensive preservation index value on any plane within the area to be evaluated; If the comprehensive preservation index value on the plane is within the comprehensive preservation index interval corresponding to the favorable zone, it is determined that the preservation conditions of the target black rock series unconventional natural gas on the plane are in the favorable zone.

2. The method for determining favorable areas for the preservation of black rock-type unconventional natural gas according to claim 1, characterized in that: The method further comprises: Using the statistical analysis method of comprehensive conservation indexes of standard areas, determine the limit values ​​of comprehensive conservation indexes corresponding to the less favorable and unfavorable areas, and determine the comprehensive conservation index interval corresponding to the more favorable area and the comprehensive conservation index interval corresponding to the unfavorable area based on the limit values ​​of comprehensive conservation indexes corresponding to the favorable and more favorable areas and the limit values ​​of comprehensive conservation indexes corresponding to the less favorable and unfavorable areas; If the comprehensive preservation index value on the plane is within the comprehensive preservation index interval corresponding to the more favorable area, it is determined that the target black rock series type unconventional natural gas preservation conditions on the plane are in the more favorable area; If the comprehensive preservation index value on the plane is within the comprehensive preservation index interval corresponding to the unfavorable zone, it is determined that the preservation conditions of the target black rock series unconventional natural gas on the plane are in the unfavorable zone.

3. The method for determining favorable areas for the preservation of black rock-type unconventional natural gas according to claim 1, characterized in that: Determining the parameter weight of each closure indicator according to each closure indicator includes: Calculate the maximum and minimum values ​​corresponding to each of the closure indicators in the area to be evaluated; Normalizing each closure index value of each evaluation point in the area to be evaluated and its corresponding maximum and minimum values; According to the normalized closing index values ​​of each evaluation point, the average value of each closing index value after normalization is calculated; For any evaluation point in the area to be evaluated, according to the normalized closure index values ​​of the evaluation point and the normalized average values ​​corresponding to the normalized closure index values, the variance of the normalized closure index values ​​is calculated; According to the variance of each closure index value of the evaluation point, the subjective weight calculation method and the objective weight calculation method are respectively used to calculate the subjective weight and the objective weight of each closure index value of the evaluation point; The parameter weight of each closure index value of the evaluation point is determined according to the subjective weight and the objective weight of each closure index value of the evaluation point.

4. The method for determining favorable areas for the preservation of black rock-type unconventional natural gas according to claim 1, characterized in that: The comprehensive preservation index, the closure indexes and their corresponding parameter weights satisfy the following relationship: in, for said comprehensive preservation index; is the parameter weight of the reservoir self-sealing index; is the reservoir self-sealing index; is the parameter weight of the caprock sealing index; is the sealing index of the cap layer; is the parameter weight of the top and bottom plate closure parameter index; is the top and bottom plate sealing parameter index; is the parameter weight of the fault sealing index; is the fault sealing index; is the parameter weight of the formation sealing index; It is an indicator of the sealing property of the formation.

5. A device for determining favorable areas for the preservation of unconventional natural gas of black rock series, characterized in that: include: An acquisition module is used to acquire evaluation parameters of the target black rock series unconventional natural gas in the area to be evaluated; wherein the evaluation parameters include reservoir parameters, top and bottom plate parameters, cap rock parameters, formation parameters and fault parameters; A construction module, used to construct corresponding closure indicators according to the evaluation parameters; A calculation module, used to determine the parameter weights of the respective closure indicators according to the respective closure indicators, and determine the comprehensive preservation indicator according to the respective closure indicators and their corresponding parameter weights; A determination module, for determining the target black rock series type unconventional natural gas preservation condition favorable area according to the comprehensive preservation index; Wherein, the building blocks are specifically used for: Constructing a reservoir self-sealing index according to the reservoir parameters; wherein the reservoir parameters include a reservoir water contact angle, a reservoir oil contact angle, a reservoir pressure, a Langmuir pressure under reservoir conditions, and a reservoir thickness; Constructing the top and bottom plate sealing index according to the top and bottom plate parameters; wherein the top and bottom plate parameters include top and bottom thickness, bottom plate thickness, top and bottom porosity, bottom plate porosity, top plate water contact angle, top plate oil contact angle, bottom plate water contact angle and bottom plate oil contact angle; Constructing a cap rock sealing index according to the cap rock parameters; wherein the cap rock parameters include cap rock lithology factors, single layer thickness and distance from the midpoint of the reservoir for each layer in the cap rock statistical layer section; Constructing a formation sealing index according to the formation parameters; wherein the formation parameters include the distance between the reservoir and the denudation zone and the formation dip angle; Constructing a fault sealing index according to the fault parameters; wherein the fault parameters include a vertical fault distance, a fault mud thickness, a distance from the fault, and a fault density; The reservoir self-sealing index is: in, is the relative wettability of the reservoir oil, dimensionless; is the reservoir thickness favorableness index, dimensionless; is the theoretical gas saturation of the reservoir, in percentage form; is the reservoir oil contact angle, in degrees; is the reservoir water contact angle, in degrees; is the reservoir pressure, in MPa; is the Langmuir pressure under reservoir conditions, in MPa; is the reservoir thickness, in m; The top and bottom plate sealing index is: in, is the closure index of the top and bottom plate thickness; is the porosity closure index of the roof and floor plates, dimensionless; is the porosity closure index of the roof and floor plates, dimensionless; is the top and bottom thickness; is the base plate thickness; is the top and bottom porosity, in percentage form; is the porosity of the base plate, in percentage form; is the water contact angle of the top plate; is the top plate oil contact angle; is the water contact angle of the bottom plate; is the contact angle of the bottom plate oil; The capping layer sealing index is: in, M The total number of layers in the cover layer section is counted; The first i The cap rock lithology factor of the layer, dimensionless; The first i The single layer thickness of the layer, in m; The first i The distance of the layer from the midpoint of the reservoir, in m; The formation sealing index is: in, is the distance between the reservoir and the denudation zone, in m; is the formation dip angle, in radians; The fault sealing index is: in, is the fault distance impact index; is the fault gouge ratio; is the fault quantity impact index; N is the number of disconnected mudstone layers; For the disconnected i The vertical thickness of the mudstone layer, in m; is the vertical throw of the fault; is the distance from the fault, in m; is the level of the main faults in the area to be evaluated; is the fault density, in units of bars / km 2 ; The determination module is specifically used for: Using the statistical analysis method of comprehensive conservation indexes of standard areas, determine the boundary values ​​of comprehensive conservation indexes corresponding to favorable and relatively favorable areas, and determine the comprehensive conservation index interval corresponding to the favorable area based on the boundary values ​​of comprehensive conservation indexes corresponding to the favorable and relatively favorable areas; Calculating a comprehensive preservation index value on any plane within the area to be evaluated; If the comprehensive preservation index value on the plane is within the comprehensive preservation index interval corresponding to the favorable zone, it is determined that the preservation conditions of the target black rock series unconventional natural gas on the plane are in the favorable zone.

6. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 4 are implemented.

7. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 4 are implemented.

Images