Reservoir productivity assessment method and device and related equipment

Abstract

The invention provides a reservoir productivity assessment method and device and related equipment, and the method comprises the steps: obtaining the logging data of a to-be-assessed reservoir target region, and the logging data comprise density logging data and interval transit time logging data; determining a fracturing index according to the logging data; determining a productivity index according to the fracturing index; and evaluating the productivity of the target region of the reservoir to be evaluated according to the productivity index. According to the method and the device, on the basis of a composite index, namely a fracturing index, factors such as inherent attributes of rock mechanics, diagenesis and influence of a crustal stress field on the complexity degree and the transformation volume of a reservoir fracturing fracture network can be comprehensively considered, the reservoir fracturing performance is continuously evaluated, the matching rate of a reservoir fracturing performance evaluation result and an actual condition is increased, and the evaluation accuracy of the reservoir fracturing performance is improved. And the selection precision of the fracturable interval is improved, and the multi-stage fracturing design precision is improved, so that the reservoir productivity evaluation precision is improved.

Description

Technical Field

[0001] The present invention relates to the field of well logging and exploration technology, and in particular to a reservoir productivity evaluation method, device and related equipment. Background Art

[0002] At present, most existing reservoir capacity assessment processes use a single index to evaluate reservoir fracturing ability, referring only to the inherent properties of rock mechanics, without taking into account the influencing factors of diagenesis and the influence of the geostress field on the complexity of the reservoir fracture network and the reformed volume. This can easily lead to large deviations between the reservoir fracturing ability evaluation results and the actual situation, resulting in large errors in the selection of fracturable layers, low precision in multi-stage fracturing design, and poor reservoir capacity assessment results. Summary of the Invention

[0003] The embodiments of the present application provide a reservoir productivity assessment method, apparatus, and related equipment, which can evaluate the reservoir fracability based on a composite index, namely the fracability index, by comprehensively considering factors such as the inherent properties of the rock, diagenesis, and the influence of the geostress field on the complexity of the reservoir fracture network and the reformed volume, thereby improving the matching rate between the reservoir fracability evaluation results and the actual situation, improving the accuracy of the selection of fracable layers, and improving the accuracy of multi-stage fracturing design, thereby improving the accuracy of reservoir productivity assessment.

[0004] In a first aspect, the present application proposes a reservoir productivity assessment method, comprising: obtaining well logging data of a target area of ​​the reservoir to be assessed, wherein the well logging data includes density logging data and acoustic time difference logging data; determining a fracturing index based on the well logging data; determining a productivity index based on the fracturing index; and assessing the productivity of the target area of ​​the reservoir to be assessed based on the productivity index.

[0005] In some feasible embodiments, the above method further includes: determining a brittleness index, a fracture toughness index, and a horizontal principal stress difference parameter based on well logging data, wherein the horizontal principal stress difference parameter is the difference between the maximum horizontal principal stress and the minimum horizontal principal stress in the target area of ​​the reservoir to be evaluated; and determining a fracturing index based on the brittleness index, the fracture toughness index, and the horizontal principal stress difference parameter.

[0006] In some feasible embodiments, the above method also includes: obtaining a first empirical parameter; determining a dynamic Young's modulus parameter and a mud content parameter based on logging data; determining a rock tensile strength parameter based on the first empirical parameter, the dynamic Young's modulus parameter and the mud content parameter; and determining a fracture toughness index based on the rock tensile strength parameter.

[0007] In some feasible embodiments, the method further comprises: determining a dynamic Young's modulus parameter and a Poisson's ratio parameter based on well logging data; and determining a brittleness index based on the dynamic Young's modulus parameter and the Poisson's ratio parameter. In some feasible embodiments, the method further comprises: obtaining a Biot coefficient; determining a Poisson's ratio parameter, a vertical geostress parameter, a formation pore pressure parameter, a Young's modulus parameter, a maximum horizontal principal strain parameter, and a minimum horizontal principal strain parameter based on the well logging data; and determining the maximum horizontal principal stress and the minimum horizontal principal stress based on the Biot coefficient, the Poisson's ratio parameter, the vertical geostress parameter, the formation pore pressure parameter, the Young's modulus parameter, the maximum horizontal principal strain parameter, and the minimum horizontal principal strain parameter.

[0008] In some feasible embodiments, the above method also includes: determining the maximum dynamic Young's modulus parameter, minimum dynamic Young's modulus parameter, maximum Poisson's ratio parameter, minimum Poisson's ratio parameter of the target area of ​​the reservoir to be evaluated, and the actual dynamic Young's modulus parameter and actual Poisson's ratio parameter corresponding to the target depth in the target area of ​​the reservoir to be evaluated based on the logging data; determining the normalized Young's modulus parameter based on the maximum dynamic Young's modulus parameter, minimum dynamic Young's modulus parameter and actual dynamic Young's modulus parameter; determining the normalized Poisson's ratio parameter based on the maximum Poisson's ratio parameter, minimum Poisson's ratio parameter and actual Poisson's ratio parameter; determining the maximum brittleness index parameter, minimum brittleness index parameter of the target area of ​​the reservoir to be evaluated, and the actual brittleness index parameter corresponding to the target depth in the target area of ​​the reservoir to be evaluated based on the normalized Young's modulus parameter and the normalized Poisson's ratio parameter; determining the normalized brittleness index based on the maximum brittleness index parameter, minimum brittleness index parameter and actual brittleness index parameter.

[0009] In some feasible embodiments, determining the fracture toughness index based on the rock tensile strength parameter also includes: determining the maximum fracture toughness index, the minimum fracture toughness index and the actual fracture toughness index corresponding to the target depth in the target area of ​​the reservoir to be evaluated based on the rock tensile strength parameter; determining the normalized fracture toughness index based on the maximum fracture toughness index, the minimum fracture toughness index and the actual fracture toughness index; determining the fracturing index based on the normalized brittleness index and the normalized fracture toughness index; when the normalized brittleness index is a positive normalized brittleness index and the normalized fracture toughness index is a negative normalized fracture toughness index, the fracturing index is the sum of the product of the positive normalized brittleness index and the negative normalized fracture toughness index and the inverse of the horizontal principal stress difference parameter.

[0010] In some feasible embodiments, the productivity index is positively correlated with the fracability index. The above method further includes: when the fracability index is greater than a preset fracability index threshold, determining that the productivity index is greater than the preset productivity index threshold, and selecting the target area of ​​the reservoir to be evaluated as a sweet spot for the fracturing project.

[0011] In a second aspect, the present application proposes a reservoir productivity evaluation device, comprising: an acquisition unit for acquiring logging data of a target area of ​​a reservoir to be evaluated, wherein the logging data includes density logging data and acoustic time difference logging data; a first determination unit for determining a fracturing index based on the logging data; a second determination unit for determining a productivity index based on the fracturing index; and an evaluation unit for evaluating the productivity of the target area of ​​the reservoir to be evaluated based on the productivity index.

[0012] In a third aspect, the present application proposes an electronic device comprising a processor and a memory, wherein the memory stores computer program instructions, and the computer program instructions are used by the processor to execute the reservoir productivity assessment method as described in any one of the above items when the processor is running.

[0013] The reservoir productivity assessment method proposed in this application includes: obtaining well logging data for the target area of ​​the reservoir to be assessed, wherein the well logging data includes density logging data and acoustic time difference logging data; determining a fracability index based on the well logging data; determining a productivity index based on the fracability index; and assessing the productivity of the target area of ​​the reservoir to be assessed based on the productivity index. This application can achieve continuous assessment of reservoir fracability based on a composite index, namely the fracability index, by comprehensively considering factors such as the inherent properties of rock mechanics, diagenesis, and the influence of the geostress field on the complexity of the reservoir fracture network and the volume of the stimulated fracture. This improves the matching rate between the reservoir fracability evaluation results and the actual situation, improves the accuracy of the selection of fracable layers, and improves the accuracy of multi-stage fracturing design, thereby improving the accuracy of reservoir productivity assessment.

[0014] The present application proposes that other advantages, objectives and features of the present application will be reflected in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the exemplary embodiments below. The accompanying drawings are for illustration purposes only and are not to be considered limiting of the present application. Throughout the drawings, like reference symbols denote like parts. In the drawings:

[0016] Figure 1 A schematic diagram of a process for evaluating reservoir productivity provided in an embodiment of the present application;

[0017] Figure 2 A schematic diagram of the effect of a reservoir productivity assessment provided in an embodiment of the present application;

[0018] Figure 3 A schematic structural diagram of a reservoir productivity assessment device provided in an embodiment of the present application;

[0019] Figure 4 A structural diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0020] In order to better understand the technical solutions provided by the embodiments of this specification, the technical solutions of the embodiments of this specification are described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of this specification and the specific features in the embodiments are detailed descriptions of the technical solutions of the embodiments of this specification, rather than limitations on the technical solutions of this specification. In the absence of conflict, the embodiments of this specification and the technical features in the embodiments can be combined with each other.

[0021] In this article, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also include elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the statement "comprising a ..." do not exclude the presence of other identical elements in the process, method, article or equipment comprising the elements. The term "two or more" includes two or more than two cases.

[0022] At present, most existing reservoir capacity assessment processes use a single index to evaluate reservoir fracturing ability, referring only to the inherent properties of rock mechanics, without taking into account the influencing factors of diagenesis and the influence of the geostress field on the complexity of the reservoir fracture network and the reformed volume. This can easily lead to problems such as large deviations between the reservoir fracturing ability evaluation results and the actual situation, large errors in the selection of fracturable layers, low accuracy in multi-stage fracturing design, and poor reservoir capacity assessment results.

[0023] The embodiments of the present application provide a reservoir productivity assessment method, apparatus, and related equipment, which can evaluate the reservoir fracability based on a composite index, namely the fracability index, by comprehensively considering factors such as the inherent properties of rock mechanics, diagenesis, and the influence of the geostress field on the complexity of the reservoir fracture network and the reformed volume, thereby improving the matching rate between the reservoir fracability evaluation results and the actual situation, improving the accuracy of fracability layer selection, and improving the accuracy of multi-stage fracturing design, thereby improving the accuracy of reservoir productivity assessment.

[0024] According to a first aspect of the present application, the present application proposes a reservoir productivity assessment method. Figure 1This is a schematic diagram of a process of a reservoir productivity assessment method 100 provided in an embodiment of the present application. Figure 1 As shown, the above method 100 may include the following steps:

[0025] Step S110 , obtaining well logging data of the target area of ​​the reservoir to be evaluated, wherein the well logging data includes density logging data and sonic time difference logging data.

[0026] For example, the target reservoir area to be evaluated can be determined based on the company's actual research area and is not specifically limited here. The logging data can also include resistivity logging data, neutron logging data, and the like, particularly density logging data and sonic transit time logging data.

[0027] Specifically, logging data of different well areas, different oil wells or different depth sections of the same oil well can be obtained.

[0028] It should be noted that a continuous logging response curve can be generated based on the logging data fitting to perform subsequent steps to obtain a continuous fracturing index and a productivity index, thereby continuously evaluating the productivity of the target area of ​​the reservoir to be evaluated.

[0029] Step S120: determining the fracturability index based on the well logging data.

[0030] For example, the brittleness index, fracture toughness index and horizontal principal stress difference parameter can be determined based on the logging data, and then the fracturing index is constructed based on the brittleness index, fracture toughness index and horizontal principal stress difference parameter to determine the productivity index.

[0031] Step S130: determining a productivity index according to the fracturability index.

[0032] For example, a relationship comparison table between the fracturability index and the productivity index can be generated by fitting based on a limited number of calculated fracturability indices and the actual productivity index of the target reservoir area to be evaluated corresponding to the above-mentioned fracturability indices, so as to determine the productivity index based on the fracturability index.

[0033] Step S140: Evaluate the productivity of the target area of ​​the reservoir to be evaluated based on the productivity index.

[0034] It should be noted that the productivity of the target area of ​​the reservoir to be evaluated is positively correlated with the above productivity index, that is, the greater the productivity index, the greater the productivity of the target area of ​​the reservoir to be evaluated.

[0035] The reservoir productivity evaluation method proposed in this application is applicable to carbonate reservoirs. This method includes: obtaining well logging data of the target area of ​​the reservoir to be evaluated, wherein the well logging data includes: density logging data and acoustic time difference logging data; determining the fracturing index based on the well logging data; determining the productivity index based on the fracturing index; and evaluating the productivity of the target area of ​​the reservoir to be evaluated based on the productivity index. This application can realize continuous evaluation of reservoir fracturing based on a composite index, i.e., a fracturing index, by comprehensively considering factors such as the inherent properties of rock mechanics, diagenesis, and the influence of the geostress field on the complexity of the reservoir fracture network and the transformation volume, thereby improving the matching rate between the reservoir fracturing evaluation results and the actual situation, improving the accuracy of the selection of fracturable layers, and improving the accuracy of multi-stage fracturing design, thereby improving the accuracy of reservoir productivity evaluation.

[0036] In some feasible embodiments, the above method further includes: determining a brittleness index, a fracture toughness index, and a horizontal principal stress difference parameter based on well logging data, wherein the horizontal principal stress difference parameter is the difference between the maximum horizontal principal stress and the minimum horizontal principal stress in the target area of ​​the reservoir to be evaluated; and determining a fracturing index based on the brittleness index, the fracture toughness index, and the horizontal principal stress difference parameter.

[0037] For example, the brittleness index can be expressed as BI, which is dimensionless. The fracture toughness index can be expressed as K IC The unit is MPa·m 1 / 2 The above maximum horizontal principal stress can be expressed as H The unit is MPa. The above minimum horizontal principal stress σ h The unit is MPa. The above horizontal principal stress difference parameter can be expressed as Δσ.

[0038] In a feasible implementation, the horizontal principal stress difference parameter can be determined based on the following formula:

[0039] Δσ=σ H ―σ h (1)

[0040] It should be noted that the aforementioned brittleness index is related to factors such as the reservoir's chemical composition, ambient temperature, stress state, and structure. The aforementioned fracture toughness index is related to the reservoir's inherent properties, such as its composition, crystal structure, ambient temperature, and stress state. The aforementioned horizontal principal stress difference parameter is used to assess the deformation and failure characteristics of the reservoir.

[0041] Therefore, the above method can determine the brittleness index, fracture toughness index and horizontal principal stress difference parameter based on logging data, and then construct a fracturing index based on multiple composite indices of the brittleness index, fracture toughness index and horizontal principal stress difference parameter, so as to evaluate the reservoir fracturing ability based on the composite index, that is, the fracturing ability index, and comprehensively consider factors such as the inherent properties of rock mechanics, diagenesis, and the influence of the ground stress field on the complexity of the reservoir fracture network and the transformation volume, thereby improving the matching rate between the reservoir fracturing evaluation results and the actual situation, improving the accuracy of the fracturing section selection, and improving the accuracy of the multi-stage fracturing design, thereby improving the accuracy of the reservoir production capacity assessment.

[0042] In some feasible embodiments, the above method also includes: obtaining a first empirical parameter; determining a dynamic Young's modulus parameter and a mud content parameter based on logging data; determining a rock tensile strength parameter based on the first empirical parameter, the dynamic Young's modulus parameter and the mud content parameter; and determining a fracture toughness index based on the rock tensile strength parameter.

[0043] For example, the first empirical parameter can be determined based on actual logging experience, specifically represented by K, and its value can be 12.26. The rock tensile strength parameter can be represented by S t The unit is MPa. The above dynamic Young's modulus parameter can be expressed as E, with the unit of GPa. The above mud content parameter can be expressed as V cl Represents dimensionless.

[0044] In a feasible implementation, the rock tensile strength parameter can be determined based on the following formula:

[0045] S t =(0.0045×E×(1―V cl )+0.008×V cl ) / K (2)

[0046] In a feasible embodiment, the fracture toughness index can be determined using the following formula:

[0047] K IC =0.271+0.107S t (3)

[0048] It should be noted that the above-mentioned dynamic Young's modulus parameter can be used to determine the deformation of the reservoir under dynamic load, the above-mentioned mud content parameter can be used to determine the proportion of mud particles in the reservoir, and the above-mentioned rock tensile strength parameter can be used to determine the ability of the reservoir to resist fracture under tension.

[0049] Therefore, the above method can accurately determine the rock tensile strength parameter based on the first empirical parameter, the dynamic Young's modulus parameter and the mud content parameter, and then accurately determine the fracture toughness index based on the rock tensile strength parameter, thereby improving the accuracy of determining the reservoir's ability to resist crack propagation, thereby accurately determining the composite index, that is, the fracturing index, and then comprehensively considering factors such as the inherent properties of rock mechanics, diagenesis, and the influence of the ground stress field on the complexity of the reservoir fracture network and the transformation volume, to continuously evaluate the reservoir fracturing ability, improve the matching rate between the reservoir fracturing ability evaluation results and the actual situation, improve the accuracy of fracturing layer selection, improve the accuracy of multi-stage fracturing design, and improve the accuracy of reservoir production capacity evaluation.

[0050] In some feasible implementations, the above method further includes: determining a dynamic Young's modulus parameter and a Poisson's ratio parameter based on well logging data; and determining a brittleness index based on the dynamic Young's modulus parameter and the Poisson's ratio parameter.

[0051] Exemplarily, the above-mentioned Poisson's ratio parameter can be represented by v, which is dimensionless.

[0052] In a feasible embodiment, the brittleness index can be determined based on the following formula:

[0053]

[0054] It should be noted that the Poisson's ratio parameter, which is the ratio of the lateral strain to the longitudinal strain of a reservoir under stress, is used to determine the deformation characteristics of the reservoir. This Poisson's ratio is related to factors such as the reservoir composition, pore pressure, ambient temperature, and stress state.

[0055] Therefore, the above method can accurately determine the dynamic Young's modulus parameters and Poisson's ratio parameters based on logging data, and then accurately determine the brittleness index based on the dynamic Young's modulus parameters and Poisson's ratio parameters, and then accurately determine the composite index, namely the fracturing index, and comprehensively consider factors such as the inherent properties of rock mechanics, diagenesis, and the influence of the ground stress field on the complexity of the reservoir fracture network and the transformation volume, to continuously evaluate the reservoir fracturing ability, improve the matching rate between the reservoir fracturing ability evaluation results and the actual situation, improve the accuracy of fracturing layer selection, improve the accuracy of multi-stage fracturing design, and improve the accuracy of reservoir production capacity evaluation.

[0056] In some feasible implementations, the above-mentioned dynamic Young's modulus parameter, the above-mentioned Poisson's ratio parameter and the above-mentioned brittleness index may also be normalized, which may be specifically achieved in the following manner: based on the logging data, determining the maximum dynamic Young's modulus parameter, the minimum dynamic Young's modulus parameter, the maximum Poisson's ratio parameter, the minimum Poisson's ratio parameter of the target area of ​​the reservoir to be evaluated, and the actual dynamic Young's modulus parameter and the actual Poisson's ratio parameter corresponding to the target depth in the target area of ​​the reservoir to be evaluated; determining the normalized Young's modulus parameter based on the maximum dynamic Young's modulus parameter, the minimum dynamic Young's modulus parameter and the actual dynamic Young's modulus parameter; determining the normalized Poisson's ratio parameter based on the maximum Poisson's ratio parameter, the minimum Poisson's ratio parameter and the actual Poisson's ratio parameter; determining the maximum brittleness index parameter, the minimum brittleness index parameter of the target area of ​​the reservoir to be evaluated, and the actual brittleness index parameter corresponding to the target depth in the target area of ​​the reservoir to be evaluated based on the normalized Young's modulus parameter and the normalized Poisson's ratio parameter; determining the normalized brittleness index based on the maximum brittleness index parameter, the minimum brittleness index parameter and the actual brittleness index parameter.

[0057] For example, the maximum dynamic Young's modulus parameter can be expressed as E max The minimum dynamic Young's modulus parameter can be expressed in GPa. min The above actual dynamic Young's modulus parameter can be expressed as E, with the unit being GPa. The above normalized Young's modulus parameter can be expressed as E n Represents dimensionless.

[0058] In a feasible embodiment, the normalized Young's modulus parameter can be determined based on the following formula:

[0059]

[0060] For example, the maximum Poisson's ratio parameter can be expressed as v max It is dimensionless. The minimum Poisson's ratio parameter can be expressed as v min The above actual Poisson's ratio parameter can be expressed as v, which is dimensionless. The above normalized Poisson's ratio parameter can be expressed as v n Represents dimensionless.

[0061] In a feasible implementation, the normalized Poisson's ratio parameter may be determined based on the following formula:

[0062]

[0063] It should be noted that after completing the normalization processing of the dynamic Young's modulus parameter and the Poisson's ratio parameter, the brittleness index can be determined based on the following formula:

[0064]

[0065] For example, the maximum brittleness index parameter can be expressed as BI max The above minimum brittleness index parameter can be expressed as BI min The above normalized brittleness index can be expressed as BI. n Represents dimensionless.

[0066] In a feasible embodiment, the normalized brittleness index can be determined based on the following formula:

[0067]

[0068] Therefore, the above method can eliminate the influence of bad data such as noise data, outlier data and missing data on the fracturing index by normalizing the dynamic Young's modulus parameter, Poisson's ratio parameter and brittleness index, thereby improving the adaptability and robustness of the method, thereby improving the matching rate between the reservoir fracturing evaluation results and the actual situation, improving the accuracy of fracturing layer selection, improving the accuracy of multi-stage fracturing design, and thus improving the accuracy of reservoir productivity assessment.

[0069] In some feasible embodiments, the above method also includes: obtaining the Biot coefficient; determining the Poisson's ratio parameter, vertical geostress parameter, formation pore pressure parameter, Young's modulus parameter, maximum horizontal principal strain parameter and minimum horizontal principal strain parameter based on the logging data; determining the maximum horizontal principal stress and the minimum horizontal principal stress based on the Biot coefficient, Poisson's ratio parameter, vertical geostress parameter, formation pore pressure parameter, Young's modulus parameter, maximum horizontal principal strain parameter and minimum horizontal principal strain parameter.

[0070] For example, the Biot coefficient can be represented by α′, and its specific value can be 1. The vertical stress parameter can be represented by σ v The above formation pore pressure parameters can be expressed in MPa. p The unit is MPa. The maximum horizontal principal strain parameter can be represented by εH, and the specific value can be 0.00097. The minimum horizontal principal strain parameter can be represented by εh, and the specific value can be 0.00005.

[0071] In a feasible implementation, the maximum horizontal principal stress can be determined based on the following formula:

[0072]

[0073] In a feasible implementation, the minimum horizontal principal stress can be determined based on the following formula:

[0074]

[0075] Therefore, the above method can accurately determine the maximum horizontal principal stress and the minimum horizontal principal stress based on the Biot coefficient, Poisson's ratio parameter, vertical geostress parameter, formation pore pressure parameter, Young's modulus parameter, maximum horizontal principal strain parameter and minimum horizontal principal strain parameter, thereby improving the determination accuracy of the horizontal principal stress difference parameter, and then improving the determination accuracy of the fracturing index, improving the assessment accuracy of the reservoir fracturing ability, improving the matching rate between the reservoir fracturing ability evaluation results and the actual situation, improving the selection accuracy of the fracturable layer section, and improving the multi-stage fracturing design accuracy, thereby improving the reservoir production capacity assessment accuracy.

[0076] In some feasible embodiments, determining the fracture toughness index based on the rock tensile strength parameter also includes: determining the maximum fracture toughness index, the minimum fracture toughness index and the actual fracture toughness index corresponding to the target depth in the target area of ​​the reservoir to be evaluated based on the rock tensile strength parameter; determining the normalized fracture toughness index based on the maximum fracture toughness index, the minimum fracture toughness index and the actual fracture toughness index; determining the fracturing index based on the normalized brittleness index and the normalized fracture toughness index; when the normalized brittleness index is a positive normalized brittleness index and the normalized fracture toughness index is a negative normalized fracture toughness index, the fracturing index is the sum of the product of the positive normalized brittleness index and the negative normalized fracture toughness index and the inverse of the horizontal principal stress difference parameter.

[0077] For example, the maximum fracture toughness index can be expressed as K IC―max The unit is MPa·m 1 / 2 The minimum fracture toughness index can be expressed as K IC―min The unit is MPa·m 1 / 2 The above actual fracture toughness index can be expressed as K IC The unit is MPa·m 1 / 2 The above normalized fracture toughness index can be expressed as K ICn Represents dimensionless.

[0078] In one possible embodiment, the inverse normalized fracture toughness index may be determined based on the following formula:

[0079]

[0080] For example, the above-mentioned fracturability index can be expressed as F rac express.

[0081] In one possible embodiment, the fracability index may be determined based on the following formula:

[0082]

[0083] In a feasible embodiment, the positive normalized fracture toughness index may also be determined based on the following formula:

[0084]

[0085] For example, when the normalized brittleness index is a positive normalized brittleness index and the normalized fracture toughness index is a positive normalized fracture toughness index, the fracturing index is the sum of the ratio of the positive normalized brittleness index to the positive normalized fracture toughness index and the inverse of the horizontal principal stress difference parameter, and can be specifically determined based on the following formula:

[0086]

[0087] It should be noted that Figure 2 This is a schematic diagram of the effect of reservoir productivity assessment provided in the embodiment of the present application, wherein the horizontal axis is the brittleness index BI n , the vertical axis is the fracturing index The orange sample points in Zone I are areas with higher production capacity, and the blue sample points in Zone II are areas with lower production capacity.

[0088] In the existing technology, most of the reservoir fracturing properties are evaluated only by the brittleness index, and then the reservoir productivity is determined. This has the problem of low accuracy and large error in judging the reservoir productivity. For example, in the brittleness index BI n If the brittleness index BI is greater than the preset threshold, for example, 0.49, the reservoir productivity is considered to be high. n If the value is less than or equal to a preset threshold, such as 0.49, the reservoir productivity is considered to be low. Figure 2 It can be seen that there is a deviation in judging reservoir productivity by relying solely on the brittleness index, and it cannot be applied to the circled blue sample points. That is, when relying solely on the brittleness index to evaluate reservoir productivity, the circled blue sample points will be judged as areas with higher productivity, which is inconsistent with the actual situation.

[0089] On the contrary, when the reservoir productivity is evaluated by the fracturing index, the evaluation result is consistent with the actual situation, with high judgment accuracy and small error. For example, when the fracturing index is greater than 0.27, the reservoir productivity is judged to be high, and when the fracturing index is less than or equal to 0.27, the reservoir productivity is judged to be low. Figure 2As shown in the figure, orange points represent areas with high productivity, and their corresponding fracability index is greater than 0.27. Blue points represent areas with low productivity, and their corresponding fracability index is less than or equal to 0.27. Therefore, using the fracability index to assess reservoir productivity can improve the accuracy of reservoir fracability assessment, increase the matching rate between reservoir fracability evaluation results and actual conditions, improve the accuracy of fracable layer selection, and enhance the accuracy of multi-stage fracturing design, thereby improving the accuracy of reservoir productivity assessment.

[0090] It should be noted that in order to improve the accuracy of productivity assessment, reservoir productivity can be evaluated based on both the brittleness index and the fracturing index.

[0091] In some feasible embodiments, the productivity index is positively correlated with the fracability index. The above method further includes: when the fracability index is greater than a preset fracability index threshold, determining that the productivity index is greater than the preset productivity index threshold, and selecting the target area of ​​the reservoir to be evaluated as a sweet spot for the fracturing project.

[0092] For example, as shown in Table 1, Table 1 is a comparison table of fracturing index and productivity index. The productivity index is the daily oil, gas and water production per meter interval, in units of m 3 / (m·d). In one feasible embodiment, the preset fracability index threshold may be 0.27, and the preset productivity index threshold may be 0.8. The productivity index is positively correlated with the fracability index. When the fracability index is greater than 0.27, it can be determined that the reservoir productivity index is greater than 0.8, and the reservoir is a Class I high-yield reservoir. When the fracability index is less than or equal to 0.27, it can be determined that the reservoir productivity index is less than or equal to 0.8, and the reservoir is a Class II low-yield reservoir.

[0093] category <![CDATA[F rac ]]> <![CDATA[Production capacity index (m 3 / (m·d))]]> I >0.27 >0.8 II ≤0.27 0-0.8

[0094] Table 1

[0095] Therefore, the above method determines that the productivity index is greater than the preset productivity index threshold when the fracturability index is greater than the preset fracturability index threshold, and selects the target area of ​​the reservoir to be evaluated as the fracturing engineering sweet spot, which can improve the efficiency and accuracy of determining the fracturing engineering sweet spot and reduce the cost of determining the fracturing engineering sweet spot.

[0096] According to a second aspect of the present application, the present application proposes a reservoir productivity assessment device. Figure 3 This is a structural diagram of a reservoir productivity assessment device 200 provided in an embodiment of the present application. Figure 3 As shown, the reservoir productivity evaluation device 200 may include:

[0097] The acquisition unit 210 is used to acquire well logging data of the target area of ​​the reservoir to be evaluated, wherein the well logging data includes density logging data and sonic time difference logging data.

[0098] The first determining unit 220 is configured to determine a fracturability index according to the well logging data.

[0099] The second determining unit 230 is configured to determine a productivity index according to the fracturability index.

[0100] The evaluation unit 240 is configured to evaluate the productivity of the target area of ​​the reservoir to be evaluated based on the productivity index.

[0101] According to a third aspect of the present application, the present application also proposes an electronic device. Figure 4 This is a structural diagram of an electronic device 300 provided in an embodiment of the present application. Figure 4 As shown, the electronic device 300 may include a processor 310 and a memory 320, wherein the memory 320 stores computer program instructions, and the computer program instructions are used by the processor to execute any of the above reservoir productivity assessment methods when executed.

[0102] A person skilled in the art can understand the specific details and beneficial effects of the reservoir productivity assessment device and electronic equipment by reading the above description of the reservoir productivity assessment method, which will not be repeated here for the sake of brevity.

[0103] It should be noted that, in the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0104] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these 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 application.

[0105] Although the preferred embodiments of this specification have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of this specification.

[0106] Obviously, those skilled in the art may make various changes and modifications to this specification without departing from the spirit and scope of this specification. Thus, if such changes and modifications fall within the scope of the claims of this specification and their equivalents, this specification is intended to include such changes and modifications.

Claims

1. A reservoir productivity assessment method, characterized in that: include: Acquire well logging data of the target area of ​​the reservoir to be evaluated, wherein the well logging data includes density logging data and acoustic time difference logging data; determining a fracturability index based on the well logging data; determining a productivity index according to the fracturability index; The productivity of the target area of ​​the reservoir to be evaluated is evaluated according to the productivity index.

2. The reservoir productivity assessment method according to claim 1, characterized in that: Also includes: Determining a brittleness index, a fracture toughness index, and a horizontal principal stress difference parameter based on the well logging data, wherein the horizontal principal stress difference parameter is the difference between the maximum horizontal principal stress and the minimum horizontal principal stress in the target area of ​​the reservoir to be evaluated; The fracturability index is determined according to the brittleness index, the fracture toughness index, and the horizontal principal stress difference parameter.

3. The reservoir productivity assessment method according to claim 2, characterized in that: Also includes: Obtaining the first empirical parameter; Determining a dynamic Young's modulus parameter and a shale content parameter based on the well logging data; Determining a rock tensile strength parameter based on the first empirical parameter, the dynamic Young's modulus parameter, and the shale content parameter; The fracture toughness index is determined according to the rock tensile strength parameter.

4. The reservoir productivity assessment method according to claim 3, characterized in that: Also includes: Determining a dynamic Young's modulus parameter and a Poisson's ratio parameter based on the well logging data; The brittleness index is determined according to the dynamic Young's modulus parameter and the Poisson's ratio parameter.

5. The reservoir productivity assessment method according to claim 4, characterized in that: Also includes: Get Biot coefficient; Determining a Poisson's ratio parameter, a vertical in-situ stress parameter, a formation pore pressure parameter, a Young's modulus parameter, a maximum horizontal principal strain parameter, and a minimum horizontal principal strain parameter based on the well logging data; The maximum horizontal principal stress and the minimum horizontal principal stress are determined according to the Biot coefficient, the Poisson's ratio parameter, the vertical ground stress parameter, the formation pore pressure parameter, the Young's modulus parameter, the maximum horizontal principal strain parameter, and the minimum horizontal principal strain parameter.

6. The reservoir productivity assessment method according to claim 5, characterized in that: Also includes: Determining, based on the well logging data, a maximum dynamic Young's modulus parameter, a minimum dynamic Young's modulus parameter, a maximum Poisson's ratio parameter, a minimum Poisson's ratio parameter of a target area of ​​the reservoir to be evaluated, and actual dynamic Young's modulus parameters and actual Poisson's ratio parameters corresponding to a target depth within the target area of ​​the reservoir to be evaluated; Determining a normalized Young's modulus parameter according to the maximum dynamic Young's modulus parameter, the minimum dynamic Young's modulus parameter, and the actual dynamic Young's modulus parameter; Determining a normalized Poisson's ratio parameter according to the maximum Poisson's ratio parameter, the minimum Poisson's ratio parameter, and the actual Poisson's ratio parameter; Determining a maximum brittleness index parameter, a minimum brittleness index parameter, and an actual brittleness index parameter corresponding to a target depth in the target area of ​​the reservoir to be evaluated based on the normalized Young's modulus parameter and the normalized Poisson's ratio parameter; A normalized brittleness index is determined according to the maximum brittleness index parameter, the minimum brittleness index parameter and the actual brittleness index parameter.

7. The reservoir productivity assessment method according to claim 6, characterized in that: Determining the fracture toughness index according to the rock tensile strength parameter further includes: Determining the maximum fracture toughness index, the minimum fracture toughness index, and the actual fracture toughness index corresponding to the target depth within the target reservoir region to be evaluated based on the rock tensile strength parameter; Determining a normalized fracture toughness index according to the maximum fracture toughness index, the minimum fracture toughness index, and the actual fracture toughness index; determining the fracturability index according to the normalized brittleness index and the normalized fracture toughness index; When the normalized brittleness index is a positive normalized brittleness index and the normalized fracture toughness index is a negative normalized fracture toughness index, the fracturing index is the sum of the product of the positive normalized brittleness index and the negative normalized fracture toughness index and the inverse of the horizontal principal stress difference parameter.

8. The reservoir productivity assessment method according to any one of claims 1 to 7, characterized in that: The productivity index is positively correlated with the fracturability index, and the method further includes: When the fracturability index is greater than a preset fracturability index threshold, it is determined that the productivity index is greater than the preset productivity index threshold, and the target area of ​​the reservoir to be evaluated is selected as a fracturing engineering sweet spot.

9. A reservoir productivity assessment device, characterized in that: include: An acquisition unit, configured to acquire well logging data of a target area of ​​a reservoir to be evaluated, wherein the well logging data includes density logging data and acoustic time difference logging data; a first determining unit, configured to determine a fracturability index based on the well logging data; a second determining unit, configured to determine a productivity index according to the fracturability index; An evaluation unit is used to evaluate the productivity of the target area of ​​the reservoir to be evaluated based on the productivity index.

10. An electronic device, characterized in that: The system comprises a processor and a memory, wherein the memory stores computer program instructions, and the computer program instructions are used by the processor to execute the reservoir productivity assessment method according to any one of claims 1 to 8 when the processor is running the computer program instructions.

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