Method and system for calculating early warning degree of hydraulic fracturing casing deformation

Abstract

The invention discloses a method and system for calculating the early warning degree of hydraulic fracturing casing deformation. The method comprises the steps that basic parameter indexes of a to-be-evaluated well section of a reservoir are collected; according to the basic parameter indexes of the current well section, calculating a redundancy coefficient representing the fusion characteristics of the casing strength and the natural fracture development state, and energy intensity representing the energy state of the artificial fracture; and quantitatively evaluating the casing deformation risk factor representing the casing deformation degree according to the redundancy coefficient and the energy intensity. According to the invention, casing deformation early warning can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of unconventional oil and gas fracturing, and particularly to a method and system for calculating the warning degree of casing deformation in hydraulic fracturing. Background Art

[0002] Horizontal well volume fracturing is a key means for unconventional oil and gas development. With the large-scale development of unconventional reservoirs such as shale gas gradually moving towards deep formations, the importance of wellbore integrity has further increased, especially the casing deformation warning for complex formations is particularly important.

[0003] Horizontal well volume fracturing uses a construction process of large displacement + large liquid volume to break the formation, but after the formation rocks are broken, stress extrusion often occurs, resulting in casing deformation, that is, the phenomenon of casing damage, deformation, and even extrusion, which brings great challenges to unconventional oil and gas development.

[0004] At present, many technologies have been formed for the back-end treatment of casing deformation, including technologies such as small bridge plug pumping staged fracturing, multiple temporary plugging fracturing, and wellbore remodeling. However, there are relatively few front-end predictions for casing deformation. Wu Dakui et al. proposed to extract the amplitude difference from geophysical exploration data to calculate the micro-fold amount to predict the casing deformation point (a method for predicting casing deformation points from seismic data, CN110485993B); Lu Qianli et al. analyzed the stress conditions of the casing system and judged the casing deformation risk by comparing the calculated shear stress with the wellbore parameters (a method for judging the casing deformation risk of horizontal wells in hydraulic fracturing of natural fracture shale formations, CN112127879B). The two provide new ideas at the theoretical end of casing deformation prevention. Although the risk division and casing deformation point prediction are carried out under the condition of no construction, there are also problems such as difficulty in real-time warning and guiding the next step during the on-site implementation process.

[0005] Therefore, in view of the problem of casing deformation warning during the on-site implementation process, the existing technology needs to provide a casing deformation warning scheme based on real-time monitoring. Summary of the Invention

[0006] The purpose of the present invention is to provide a casing deformation warning scheme based on real-time monitoring of artificial fractures, so as to provide technical support for real-time casing deformation warning in the transformation of unconventional reservoirs.

[0007] To solve the above technical problems, an embodiment of the present invention provides a method for calculating the warning degree of casing deformation in hydraulic fracturing, including: collecting the basic parameter indicators of the reservoir well section to be evaluated; calculating a redundancy coefficient characterizing the fusion characteristics of casing strength and natural fracture development state, and an energy intensity characterizing the energy state of artificial fractures according to the basic parameter indicators of the current well section; quantitatively evaluating a casing deformation risk factor characterizing the degree of casing deformation according to the redundancy coefficient and the energy intensity.

[0008] Preferably, the casing deformation risk factor is calculated using the following expression:

[0009]

[0010] where D c represents the casing deformation risk factor, μ represents the redundancy coefficient, and E ω represents the energy intensity.

[0011] Preferably, in the process of calculating the redundancy coefficient according to the basic parameter indexes of the reservoir layer position, it includes: calculating the natural fracture coefficient according to the natural fracture dip index, natural fracture density index and horizontal section length of the current well section; calculating the casing strength coefficient according to the horizontal minimum principal stress index, horizontal maximum principal stress index and casing external collapse strength of the current well section; obtaining the redundancy coefficient according to the natural fracture coefficient and the casing strength coefficient.

[0012] Preferably, the natural fracture coefficient, the casing strength coefficient and the redundancy coefficient are calculated using the following expressions respectively:

[0013] f F = 2.415×10 -3 ×c β ×c θ ×L

[0014]

[0015] μ = 2.63×f F ×λ σ

[0016] where f F represents the natural fracture coefficient, c θ represents the natural fracture dip index, c β represents the natural fracture density index, L represents the horizontal section length, λ σ represents the casing strength coefficient, σ T represents the casing external collapse strength, σ H represents the horizontal maximum principal stress index, σ h represents the horizontal minimum principal stress index, and μ represents the redundancy coefficient.

[0017] Preferably, in the process of calculating the energy intensity according to the basic parameter indexes of the reservoir layer position, it includes: calculating the average moment energy level and average distance of the current well section according to the number of event points, moment energy level of each event point and distance between each event point and the wellbore in the real-time monitoring data of artificial fractures; calculating the energy intensity according to the average moment energy level and average distance of the current well section.

[0018] Preferably, the energy intensity is calculated using the following expression:

[0019]

[0020] Among them, E ω represents the energy intensity, and E M represents the average moment energy level, and E L represents the average distance.

[0021] Preferably, the average moment energy level and the average distance are calculated by using the following expressions:

[0022]

[0023] Among them, E M represents the average moment energy level, E L represents the average distance, n represents the total number of event points, i represents the serial number of the event point, and E Mi represents the moment energy level of the i-th event point, and E Li represents the distance between the i-th event point and the wellbore.

[0024] Preferably, the magnitude of the casing deformation risk factor is positively correlated with the degree of casing deformation risk.

[0025] On the other hand, an embodiment of the present invention provides a computer-readable storage medium, which includes a series of instructions for executing the method steps as described above.

[0026] In addition, an embodiment of the present invention further provides a system for calculating the warning degree of hydraulic fracturing casing deformation, including: a data collection module configured to collect basic parameter indexes of the well section to be evaluated in the reservoir; an evaluation index calculation module configured to calculate a redundancy coefficient characterizing the fusion characteristics of the casing strength and the natural fracture development state and an energy intensity characterizing the energy state of the artificial fracture according to the basic parameter indexes of the current well section; a casing deformation risk evaluation module configured to quantitatively evaluate a casing deformation risk factor characterizing the degree of casing deformation according to the redundancy coefficient and the energy intensity.

[0027] Compared with the prior art, one or more of the above embodiments may have the following advantages or beneficial effects:

[0028] The present invention proposes a method and a system for calculating the warning degree of hydraulic fracturing casing deformation. The method and the system clarify the initial redundancy coefficient through statistical analysis of single-well natural geomechanical parameters and casing strength parameters, and then calculate the energy magnitude, quantity of stress response event points and the distance between the event points and the wellbore through real-time monitoring data of artificial fractures, and then analyze the energy intensity, and finally calculate the casing deformation risk factor according to the redundancy coefficient and the energy intensity. The present invention considers the application of artificial fracture monitoring means, effectively solves the problem of on-site construction warning, and provides technical support for ensuring wellbore integrity.

[0029] Other features and advantages of the present invention will be set forth in the following description, and in part will be obvious from the description, or may be learned by practice of the present invention. The objectives and other advantages of the present invention may be realized and attained by the structure particularly pointed out in the specification, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings are provided to further understand the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention. In the drawings:

[0031] Figure 1 It is a schematic diagram of the steps of the method for calculating the casing deformation warning level in the embodiment of the present application.

[0032] Figure 2 It is a block diagram of the modules of the system for calculating the casing deformation warning level in the embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The following will describe in detail the embodiments of the present invention in conjunction with the drawings and embodiments, so as to fully understand how the present invention uses technical means to solve technical problems and achieve the realization process of technical effects and implement accordingly. It should be noted that as long as there is no conflict, the various embodiments in the present invention and the various features in each embodiment can be combined with each other, and the formed technical solutions are all within the protection scope of the present invention.

[0034] In addition, the steps shown in the flowchart of the drawings can be executed in a computer system such as a set of computer-executable instructions. And although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0035] The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms "a" and "an" used herein are also intended to include the plural. It should also be understood that the terms "comprises" and / or "comprising" used herein specify the presence of the stated features, integers, steps, operations, units and / or components, and do not preclude the presence or addition of one or more other features, integers, steps, operations, units, components and / or combinations thereof.

[0036] Horizontal well volume fracturing is a key means for unconventional oil and gas development. With the large-scale development of unconventional reservoirs such as shale gas gradually moving towards deep formations, the importance of wellbore integrity has further increased, especially the casing deformation warning for complex formations is particularly important.

[0037] Horizontal well volume fracturing uses a construction process of large displacement + large liquid volume to break the formation, but after the formation rock is broken, stress extrusion often occurs, resulting in casing deformation. In view of the phenomenon of casing damage, deformation, and even extrusion, it has brought huge challenges to the development of unconventional oil and gas.

[0038] At present, many technologies have been formed for the back-end treatment of casing deformation, including technologies such as small bridge plug pumping sectional fracturing, multiple temporary plugging fracturing, and wellbore reshaping. However, relatively few studies have been conducted on the front-end prediction of casing deformation. Wu Dakui et al. proposed to extract the amplitude difference from geophysical data to calculate the micro-fold amount to predict the casing deformation point (a method for predicting casing deformation points from seismic data, CN110485993B); Lu Qianli et al. analyzed the stress condition of the casing system and judged the casing deformation risk by comparing the calculated shear stress with the wellbore parameters (a method for judging the casing deformation risk of horizontal wells in natural fracture shale formations during hydraulic fracturing, CN112127879B). The two provide new ideas at the theoretical end of casing deformation prevention. Although risk division and casing deformation point prediction have been carried out under unconstructed conditions, there are also problems such as difficulty in real-time warning and guiding in the next step during on-site implementation.

[0039] To solve the above technical problems, the embodiments of the present application propose a method and system for calculating the casing deformation warning degree of hydraulic fracturing. The method and system first count the basic geological engineering parameters of a single well to calculate the redundancy coefficient, then calculate the energy size, quantity of stress response event points, and the distance between the event points and the wellbore through real-time monitoring data of artificial fractures, and then analyze the energy intensity. Finally, the casing deformation risk factor is calculated according to the redundancy coefficient and the energy intensity to achieve casing deformation warning.

[0040] Example 1

[0041] Figure 1 It is a schematic diagram of the steps of the method for calculating the casing deformation warning degree of hydraulic fracturing in the embodiments of the present application. The following describes the specific step flow of the method for calculating the casing deformation warning degree of hydraulic fracturing (also referred to as the "casing deformation warning method") described in the embodiments of the present invention.

[0042] As Figure 1 shown, step S110 is the basic parameter index of the target layer reservoir in the well section to be evaluated. In step S110, in the step of collecting the basic parameter indexes of the well section to be evaluated of the reservoir, the embodiments of the present invention calculate each basic parameter index of the well section to be evaluated according to the actual data of each basic parameter of the well section to be evaluated collected.

[0043] Among them, in the embodiments of the present invention, the basic parameters include: the dip angle c of natural fractures θ , the density c of natural fractures β , the horizontal section length L, the horizontal minimum principal stress σ h , the horizontal maximum principal stress σH 、The external collapse strength σ of the casing T 、and the real-time monitoring data of artificial fractures. The real-time monitoring data of artificial fractures includes but is not limited to: the total number n of event points, the moment magnitude E of a single event point Mi and the distance E between a single event point and the wellbore Li .

[0044] In one embodiment, the dip angle (index) c of natural fractures in the current well section θ is the geometric mean of the dip angles of all natural fractures in the target interval, and the natural fracture density (index) c β is the geometric mean of the densities of all natural fractures in the target interval. In addition, the dip angle index and natural fracture density index of the well section to be evaluated can also be obtained through acoustic far detection or core observation or downhole imaging logging data.

[0045] In one embodiment, all minimum horizontal principal stress data and all maximum horizontal principal stress data sets of the reservoir section to be evaluated can be calculated first based on the stress model and through in-situ stress tests or logging data in the laboratory, so as to obtain the minimum horizontal principal stress (index) σ of the well section to be evaluated by calculating the average value of the minimum horizontal principal stress data h , and the maximum horizontal principal stress (index) σ of the well section to be evaluated can be obtained by calculating the average value of the maximum horizontal principal stress data H . In addition, the external collapse strength σ of the casing T depends on the casing material and wall thickness, and this parameter can be obtained by querying the casing steel nameplate.

[0046] In one embodiment, the real-time monitoring data of artificial fractures is obtained in real time by the microseismic monitoring method.

[0047] Thus, after collecting the actual data and calculating each index, it enters step S120.

[0048] Reference Figure 1 , in step S120, according to the basic parameter indexes of the current well section collected in step S110, the redundancy coefficient characterizing the fusion characteristics of the casing strength and the development state of natural fractures and the energy intensity characterizing the energy state of artificial fractures are calculated respectively.

[0049] In step S120, in the process of calculating the redundancy coefficient according to the basic parameter indexes of the reservoir layer position, it includes: first, calculating the natural fracture coefficient according to the dip angle index, natural fracture density index and horizontal section length of the current well section; then, calculating the casing strength coefficient according to the horizontal minimum principal stress index, horizontal maximum principal stress index and external collapse strength of the casing of the current well section; finally, obtaining the redundancy coefficient according to the natural fracture coefficient and casing strength coefficient of the current well section.

[0050] In one embodiment, the natural fracture coefficient characterizing the development state of natural fractures is calculated by calculating the product of a first preset coefficient, the natural fracture dip angle index, the natural fracture density index, and the horizontal section length. Among them, the natural fracture coefficient of the current well section is expressed by the following expression:

[0051] f F = 2.415×10 -3 ×c β ×c θ ×L (1)

[0052] Among them, f F represents the natural fracture coefficient, dimensionless; c θ represents the natural fracture dip angle index, with the unit of °; c β represents the natural fracture density index, with the unit of number of fractures per meter; L represents the horizontal section length, with the unit of m. In the embodiment of the present invention, the first preset coefficient is 2.415.

[0053] In one embodiment, first calculate the difference between the horizontal maximum principal stress index and the horizontal maximum principal stress index of the current well section, then perform a division operation on the external collapse strength of the casing and the current principal stress difference, and finally multiply the result of the current division operation by a second preset coefficient to calculate the casing strength coefficient characterizing the artificial casing strength state. Among them, the casing strength coefficient of the current well section is expressed by the following expression:

[0054]

[0055] Among them, λ σ represents the casing strength coefficient, dimensionless; σ T represents the external collapse strength of the casing, with the unit of MPa; σ H represents the horizontal maximum principal stress index, with the unit of MPa; σ h represents the horizontal minimum principal stress index, with the unit of MPa. In the embodiment of the present invention, the second preset coefficient is 0.8.

[0056] In one embodiment, the redundancy coefficient is calculated by calculating the product of a third preset coefficient, the natural fracture coefficient, and the casing strength coefficient. Among them, the redundancy coefficient of the current well section is expressed by the following expression:

[0057] μ = 2.63×f F ×λ σ (3)

[0058] Among them, μ represents the redundancy coefficient. In the embodiment of the present invention, the third preset coefficient is 2.63.

[0059] Next, in step S120, in the process of calculating the energy intensity according to the basic parameter indexes of the reservoir layer position, it includes: First, according to the number of event points in the current well section, the moment energy level of each event point, and the distance between each event point and the wellbore in the real-time monitoring data of artificial fractures, calculate the average moment energy level and the average distance of the current well section; then, calculate the energy intensity according to the average moment energy level and the average distance of the current well section.

[0060] Specifically, according to the number of event points in the current well section and the moment energy level of each event point, use the weighted average algorithm to calculate the average moment energy level (index) of the current well section. At the same time, according to the number of event points in the current well section and the distance between each event point and the wellbore, use the weighted average algorithm to calculate the average distance (index) of the current well section.

[0061] The average moment energy level and the average distance of the current well section are calculated using the following expressions:

[0062]

[0063] Among them, E M represents the average moment energy level, dimensionless; E L represents the average distance, with the unit of m; n represents the total number of event points; i represents the event point serial number; E Mi represents the moment energy level of the i-th event point, dimensionless; E Li represents the distance between the i-th event point and the wellbore, with the unit of m;.

[0064] In one embodiment, calculate the energy intensity according to the average moment energy level and the average distance of the current well section. Among them, the energy intensity is calculated using the following expression:

[0065]

[0066] Among them, E ω represents the energy intensity.

[0067] In this way, through the above expressions (1) to (5), the redundancy coefficient representing the fusion characteristics of the casing strength and the fracture development state corresponding to the current well section, and the energy intensity representing the energy state of the fracture are calculated, and then enter step S130.

[0068] Step S130 quantitatively evaluates the casing deformation risk factor representing the degree of casing deformation according to the redundancy coefficient and the energy intensity.

[0069] In step S130, first calculate the absolute value of the difference between the redundancy coefficient and the energy intensity, and then calculate the ratio of the current absolute value of the difference to the redundancy coefficient, so as to obtain the casing deformation risk factor representing the degree of casing deformation of the current well section. Among them, the casing deformation risk factor is calculated using the following expression:

[0070]

[0071] Among them, D c represents the casing deformation risk factor.

[0072] In the embodiment of the present invention, the magnitude of the casing deformation risk factor is positively correlated with the degree of casing deformation risk. That is to say, the larger the value of the casing deformation risk factor, the greater the casing deformation risk of the current well section; on the contrary, the smaller the value of the casing deformation risk factor, the smaller the casing deformation risk of the current well section, and the safer it is.

[0073] Example 2

[0074] Based on the casing deformation warning method described in Embodiment 1, the casing deformation warning degree of Well X in the Sichuan Basin in the embodiment of the present invention is calculated as an example.

[0075] Step A: Collect the basic geological engineering parameters of Well X, the horizontal minimum principal stress σ h is 76.82 MPa, the horizontal maximum principal stress σ H is 86.26 MPa, the horizontal section length L is 1500 m, the natural fracture dip angle c θ is 22°, the natural fracture density c β is 0.08 fractures / m, the external collapse strength of the casing σ T is 172 MPa, the single event point moment energy level E Mi provided by microseismic monitoring, the number of event points n, and the distance E Li from a single event point to the wellbore are shown in Table 1.

[0076] Table 1 Data table of the moment energy level and the distance to the wellbore of each event point

[0077] i 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 <![CDATA[E Mi > 2.1 1.2 0.8 1.6 0.2 0.7 1.4 1.1 2.0 2.9 2.7 1.3 2.7 0.5 1.2 1.1 2.9 0.5 0.6 2.9 <![CDATA[E Li > 164.5 58.2 117.3 119.3 39.2 66.4 174.2 38.4 0.2 48.0 125.2 3.8 31.7 67.2 14.9 75.4 181.3 32.1 138.9 157.8 i 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 <![CDATA[E Mi > 0.9 1.1 1.9 0.5 2.2 1.2 0.9 1.7 2.4 2.6 1.3 2.9 1.9 0.8 0.4 1.1 2.2 2.7 2.7 0.8 <![CDATA[E Li > 192.4 204.2 48.7 208.4 157.1 31.4 70.1 63.1 10.3 84.2 183.7 248.6 115.3 140.0 228.3 5.3 131.9 122.6 38.6 172.4 i 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 <![CDATA[E Mi > 2.8 1.7 1.0 1.7 2.4 1.8 1.3 0.7 2.6 0.4 2.2 2.6 1.3 2.1 0.4 1.3 0.9 1.7 2.7 2.5 <![CDATA[E Li > 36.8 30.5 75.4 59.5 64.8 50.9 28.3 64.6 14.9 47.4 61.4 25.1 80.8 91.2 85.9 89.2 23.3 11.4 55.5 15.6 i 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 <![CDATA[E Mi > 2.9 1.4 2.4 0.3 0.4 0.4 1.3 1.3 0.7 2.8 2.5 0.8 1.4 1.9 0.3 0.1 1.3 0.2 2.4 0.4 <![CDATA[E Li > 84.2 62.5 6.0 165.1 78.2 36.7 19.7 92.3 43.5 18.9 70.7 46.8 8.2 157.5 104.5 106.2 166.5 217.5 104.2 198.2 i 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 <![CDATA[E Mi > 0.6 2.1 2.7 0.6 2.7 2.7 0.2 0.8 0.2 0.8 2.8 0.4 1.2 2.2 2.8 1.8 1.4 2.3 1.5 2.2 <![CDATA[E Li > 57.6 37.8 152.0 191.6 146.2 129.6 14.9 93.0 11.3 1.0 14.5 55.6 7.1 30.6 239.1 139.3 158.1 213.2 153.7 70.4 i 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 <![CDATA[E Mi > 0.9 1.7 0.3 1.3 0.8 0.1 1.1 0.7 1.1 0.6 2.1 1.1 2.3 0.2 2.1 1.2 <![CDATA[E Li > 52.3 91.2 84.0 61.2 141.5 97.7 99.2 150.1 85.0 185.8 0.9 114.8 191.6 39.7 20.5 45.3

[0078] Step B: According to the natural fracture dip angle c θ and the natural fracture density c β obtained in Step A and the horizontal section length L, calculate the natural fracture coefficient f F as 6.3756 according to Expression (1).

[0079] Step C: According to the horizontal minimum principal stress σ h and the horizontal maximum principal stress σ H and the external collapse strength of the casing σ T obtained in Step A, calculate the strength coefficient λ σ as 14.5763 according to Expression (2).

[0080] Step D: According to the natural fracture coefficient f Fis 6.3756, and the strength coefficient λ obtained according to step C σ is 14.5763. Calculate the redundancy coefficient μ according to expression (3) to be 244.4129.

[0081] Step E: According to the single-event point moment energy level E obtained in step A Mi , the number of event points n, and the distance between the single-event point and the wellbore E Li , calculate the average moment energy level E according to expression (4) M is 1.4784, and the average distance E L is 88.6888 m.

[0082] Step F: According to the average moment energy level E obtained in step E M is 1.4784, and the average distance E L is 88.6888 m, calculate the energy intensity E according to expression (5) ω is 22.8270.

[0083] Step G: According to the redundancy coefficient μ obtained in step D, which is 244.4129, and the energy intensity E obtained in step F ω is 22.8270, calculate the casing deformation risk factor D according to expression (6) c is 0.9066.

[0084] Currently, this casing deformation warning method has been applied to more than 40 well sections in a shale gas field in the Sichuan Basin, and the warning effective rate reaches 84.1%, with an increase of 29.8% compared with the previous period, and the application effect is remarkable.

[0085] Example 3

[0086] Based on the above casing deformation warning method, an embodiment of the present invention also provides a computer-readable storage medium, on which a computer program is stored, and the computer program is executed to run a casing deformation warning method. The computer program can run computer instructions, and the computer instructions include computer program code, and the computer program code can be in the form of source code, object code, executable file or some intermediate form, etc.

[0087] The computer-readable storage medium can include: any entity or device capable of carrying computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disc, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electrical carrier signal, telecommunication signal, and software distribution medium, etc.

[0088] It should be noted that the content included in the computer-readable storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice within the jurisdiction. For example, in some jurisdictions, it can be appropriately increased or decreased according to the requirements of legislation and patent practice. For example, in some jurisdictions, it can be appropriately increased or decreased according to the requirements of legislation and patent practice. For example, in some jurisdictions, according to patent practice, the computer-readable storage medium does not include electrical carrier signals and telecommunication signals.

[0089] Example 4

[0090] Based on the casing deformation warning method described in the above Embodiment 1 or Embodiment 2, the present invention further provides a system for calculating the casing deformation warning degree of hydraulic fracturing (also referred to as the "casing deformation warning system").

[0091] Figure 2 It is a block diagram of the modules of the system for calculating the casing deformation warning degree of hydraulic fracturing according to the embodiments of the present application. As Figure 2 shown, the casing deformation warning system described in the embodiments of the present invention includes: a data collection module 21, an evaluation index calculation module 22, and a casing deformation risk evaluation module 23.

[0092] Specifically, the data collection module 21 is implemented according to the method described in the above step S110, and is configured to collect the basic parameter indexes of the well section to be evaluated in the reservoir; the evaluation index calculation module 22 is implemented according to the method described in the above step S120, and is configured to calculate the redundancy coefficient characterizing the fusion characteristics of the casing strength and the natural fracture development state, and the energy intensity characterizing the energy state of the artificial fracture according to the basic parameter indexes of the current well section; the casing deformation risk evaluation module 23 is implemented according to the method described in the above step S130, and is configured to quantitatively evaluate the casing deformation risk factor characterizing the casing deformation degree according to the redundancy coefficient and the energy intensity.

[0093] The present invention discloses a method and a system for calculating the casing deformation warning degree of hydraulic fracturing. The method and the system clarify the initial redundancy coefficient through statistical analysis of the single-well natural geomechanical parameters and the casing strength parameters, and then calculate the energy size, quantity and the distance between the event point and the wellbore of the stress response event points through the real-time monitoring data of the artificial fracture, and then analyze the energy intensity. Finally, the casing deformation risk factor is calculated according to the redundancy coefficient and the energy intensity. The present invention takes into account the application of the artificial fracture monitoring means, effectively solves the problem of on-site construction implementation warning, and provides technical support for ensuring the wellbore integrity.

[0094] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

[0095] In the description of the present invention, unless otherwise specified, "a plurality of" means two or more; the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, terms such as "first", "second", "third", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0096] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0097] It should be understood that the embodiments disclosed in the present invention are not limited to the specific structures, processing steps or materials disclosed herein, but should extend to equivalent alternatives of these features understood by those of ordinary skill in the relevant art. It should also be understood that the terms used herein are only for the purpose of describing specific embodiments and do not imply limitation.

[0098] The "one embodiment" or "embodiment" mentioned in the specification means that the specific features, structures or characteristics described in connection with the embodiment are included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment" or "embodiment" that appear throughout the specification do not necessarily all refer to the same embodiment.

[0099] Although the embodiments disclosed in the present invention are as above, the content described is only an embodiment adopted for the convenience of understanding the present invention and is not intended to limit the present invention. Any person skilled in the art within the technical field to which the present invention pertains may make any modifications and changes in the form of implementation and details without departing from the spirit and scope disclosed by the present invention. However, the scope of patent protection of the present invention shall still be subject to the scope defined by the appended claims.

Claims

1. A method for calculating the warning level of casing deformation in hydraulic fracturing, characterized in that, it includes: Collect the basic parameter indicators of the reservoir well section to be evaluated; According to the basic parameter indicators of the current well section, calculate the redundancy coefficient characterizing the fusion characteristics of casing strength and natural fracture development state, and the energy intensity characterizing the energy state of artificial fractures; According to the redundancy coefficient and the energy intensity, quantitatively evaluate the casing deformation risk factor characterizing the degree of casing deformation.

2. The method according to claim 1, characterized in that, the following expression is used to calculate the casing deformation risk factor: Among them, D c represents the casing change risk factor, μ represents the redundancy coefficient, and E ω represents the energy intensity.

3. The method according to claim 1 or 2, characterized in that, in the process of calculating the redundancy coefficient according to the basic parameter indicators of the reservoir layer, it includes: Calculate the natural fracture coefficient according to the natural fracture dip angle index, natural fracture density index and horizontal section length of the current well section; Calculate the casing strength coefficient according to the horizontal minimum principal stress index, horizontal maximum principal stress index and casing external extrusion resistance strength of the current well section; Obtain the redundancy coefficient according to the natural fracture coefficient and the casing strength coefficient.

4. The method according to claim 3, characterized in that, the following expressions are respectively used to calculate the natural fracture coefficient, the casing strength coefficient and the redundancy coefficient: f F = 2.415×10 -3 ×c β ×c θ ×L μ = 2.63×f F ×λ σ Among them, f F represents the natural fracture coefficient, c θ represents the natural fracture dip angle index, c β represents the natural fracture density index, L represents the horizontal section length, λ σ represents the casing strength coefficient, σ T represents the external collapse strength of the casing, σ H represents the horizontal maximum principal stress index, σ h represents the horizontal minimum principal stress index, and μ represents the redundancy coefficient.

5. The method according to any one of claims 1 to 4, characterized in that, in the process of calculating the energy intensity according to the basic parameter indicators of the reservoir layer, it includes: Calculate the average moment energy level and average distance of the current well section according to the number of event points, the moment energy level of each event point and the distance between each event point and the wellbore in the real-time monitoring data of artificial fractures; Calculate the energy intensity according to the average moment energy level and average distance of the current well section.

6. The method according to claim 5, characterized in that, the following expression is used to calculate the energy intensity: Among them, E ω represents the energy intensity, E M represents the average moment energy level, E L represents the average distance.

7. The method according to claim 5 or 6, characterized in that, the following expression is used to calculate the average moment energy level and the average distance: Among them, E M represents the average moment energy level, E L represents the average distance, n represents the total number of event points, i represents the event point serial number, E Mi represents the moment energy level of the i-th event point, E Li represents the distance between the i-th event point and the wellbore.

8. The method according to any one of claims 1 to 7, characterized in that, the magnitude of the casing deformation risk factor is positively correlated with the degree of casing deformation risk.

9. A computer-readable storage medium, characterized in that, it contains a series of instructions for executing the method steps according to any one of claims 1 to 8.

10. A system for calculating the warning level of casing deformation in hydraulic fracturing, characterized in that, it includes: A data collection module configured to collect the basic parameter indicators of the reservoir well section to be evaluated; An evaluation index calculation module configured to calculate the redundancy coefficient characterizing the fusion characteristics of casing strength and natural fracture development state, and the energy intensity characterizing the energy state of artificial fractures according to the basic parameter indicators of the current well section; A casing deformation risk evaluation module configured to quantitatively evaluate the casing deformation risk factor characterizing the degree of casing deformation according to the redundancy coefficient and the energy intensity.

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