A sand plug risk early warning method and device for shale gas fracturing construction

Abstract

The application discloses a sand plugging risk early warning method and device for shale gas fracturing construction, and the method comprises the following steps: acquiring real-time oil pressure data, establishing a wellbore pressure time sequence according to the real-time oil pressure data; calculating oil pressure characteristic data according to the wellbore pressure time sequence; determining a sand plugging early warning index according to the oil pressure characteristic data; judging whether the sand plugging early warning index exceeds a preset sand plugging threshold range; if the sand plugging early warning index exceeds the preset sand plugging threshold range, an early warning signal is sent; if the sand plugging early warning index does not exceed the preset sand plugging threshold range, it is judged whether the fracturing construction is completed, and if the fracturing construction is completed, the early warning is stopped. The information results obtained by mining various fracturing oil pressure curve data are given a sand plugging early warning index by using a weight method, which is convenient for field construction personnel to make a judgment, enhances the visual effect, and gives a sand plugging early warning index judgment range in combination with specific analysis of big data, so that the accuracy of the early warning is ensured and guidance is provided for shale gas fracturing construction.

Description

Technical Field

[0001] This invention relates to the field of sand plugging risk early warning technology in fracturing operations, specifically to a sand plugging risk early warning method and device for shale gas fracturing operations. Background Technology

[0002] With the large-scale investment and promising results of shale gas fracturing development in my country, shale gas, as an unconventional oil and gas resource, has increasingly become a major force in solving my country's "gas shortage" problem. Monitoring horizontal well fracturing operations is an indispensable part of the process. Experienced operators can make judgments about the formation conditions and adjust the fracturing procedures in a timely manner by observing the fluctuations in oil pressure, displacement, and sand ratio curves on the fracturing operation curve. Special situations often arise during fracturing operations, such as insufficient sand-carrying capacity of the fracturing fluid, causing quartz sand or ceramsite to settle near the wellbore and form sand plugs; or excessive sand injection leading to severe sand accumulation near the wellbore and sand plugging. These special situations are reflected in the fracturing operation curve as an abnormal increase in oil pressure within a short period. If not addressed promptly, this can lead to unimaginable consequences.

[0003] Sand plugging during fracturing often forms rapidly within about 20 seconds during the fracturing operation. Its main characteristics are speed and unpredictability. Currently, the conventional methods for early warning of sand plugging in fracturing include the double logarithmic slope method of oil pressure time and the double logarithmic slope method of net pressure time. Although these methods react quickly, the actual fracturing operation curve often fluctuates greatly. Even during the stable period, there are sharp rises and falls in pressure, although they are not very obvious. Therefore, in actual early warning, these methods have the problems of unstable early warning results and large differences in early warning results.

[0004] Therefore, there is a need to propose a sand plugging early warning method and device for shale gas fracturing operations, which can filter out the situation of sharp rises and falls during the stable period without affecting the accuracy and sensitivity of sand plugging early warning, and accurately warn of sand plugging risks in fracturing operations, so as to ensure the safe conduct of fracturing operations. Summary of the Invention

[0005] This invention provides a method and device for early warning of sand plugging risk in shale gas fracturing operations, which overcomes the technical problem that existing fracturing sand plugging early warning methods have unstable early warning results and large differences in early warning results due to the large fluctuations in the fracturing operation curve and the sharp rise and fall of pressure during the stable period.

[0006] To address the aforementioned problems, this invention provides a method for early warning of sand plugging risk in shale gas fracturing operations, comprising:

[0007] Acquire real-time oil pressure data, and establish a wellbore pressure time series based on the real-time oil pressure data;

[0008] Calculate oil pressure characteristic data based on the wellbore pressure time series;

[0009] The sand blockage early warning index is determined based on the oil pressure characteristic data;

[0010] Determine whether the sand blockage warning index exceeds the preset sand blockage threshold range; if the sand blockage warning index exceeds the preset sand blockage threshold range, issue a warning signal; if the sand blockage warning index does not exceed the preset sand blockage threshold range, determine whether the fracturing operation has ended; if the fracturing operation has ended, stop issuing warnings.

[0011] Furthermore, the hydraulic pressure characteristic data includes at least the hydraulic pressure time slope, the rate of change of the hydraulic pressure time slope, the real-time hydraulic pressure increment, and the fitted hydraulic pressure intercept.

[0012] Furthermore, the method for calculating the hydraulic pressure time slope includes:

[0013] Based on the oil pressure at each moment in the oil pressure time series, the oil pressure change and time change are determined, and the oil pressure slope is obtained; the calculation formula is:

[0014]

[0015] Where k′ is the hydraulic time slope; P i P represents the current oil pressure. i-1 The oil pressure at time i-1; t i For time i; t i-1 This is the (i-1)th time.

[0016] Furthermore, the method for calculating the real-time oil pressure increment includes:

[0017] The oil pressure increment is obtained based on the maximum and minimum oil pressure data within a preset time period; the calculation formula is:

[0018] P Z =Max(P) - Min(P)

[0019] Among them, P Z For the oil pressure increment, Max(P) is the maximum oil pressure within a preset time period, and Min(P) is the minimum oil pressure within a preset time period.

[0020] Furthermore, the method for calculating the fitted oil pressure intercept includes:

[0021] The least squares method was used to perform univariate linear regression analysis on the oil pressure and time of a continuous preset number of sampling points to obtain the fitted regression curve;

[0022] The fitted oil pressure is obtained based on the fitted regression curve;

[0023] By using the intercept of the fitted oil pressure according to the linear equation, the variation of the fitted oil pressure under different fitted curves is determined.

[0024] Furthermore, the method for calculating the sand blockage early warning index includes:

[0025] The weighted method is used to calculate the sand blockage early warning index based on the oil pressure time slope, the rate of change of oil pressure time slope, the real-time oil pressure increment, and the fitted oil pressure intercept; the specific method is as follows:

[0026] Assuming the standardized value of the oil pressure time slope is index B1, the standardized value of the oil pressure time slope change rate is index B2, the standardized value of the oil pressure increment is index B3, and the standardized value of the fitted oil pressure intercept is index B4, then the sand blockage warning index WI is:

[0027] WI = w1B1 + w2B2 + w3B3 + w4B4

[0028] Among them, w i (i = 1, 2, 3, 4) represent the importance of each indicator.

[0029] Furthermore, the method for determining whether the fracturing operation has ended includes:

[0030] Obtain fracturing construction design parameters and fracturing construction status parameters;

[0031] Determine whether the fracturing operation status parameters have reached the standard of the fracturing operation design parameters; if the standard of the design parameters has been reached, then determine that the fracturing operation has ended.

[0032] Furthermore, the fracturing construction design parameters include fracturing construction parameters such as section length, design sand addition amount, design fluid volume, and wellbore diameter.

[0033] This invention also provides a sand plugging risk early warning device for shale gas fracturing operations, comprising:

[0034] The data acquisition module is used to acquire real-time oil pressure data and establish a wellbore pressure time series based on the real-time oil pressure data;

[0035] The analysis module is used to calculate oil pressure characteristic data based on the wellbore pressure time series;

[0036] The calculation module is used to determine the sand blockage early warning index based on the oil pressure characteristic data;

[0037] The judgment module is used to determine whether the sand blockage warning index exceeds the preset sand blockage threshold range; if the sand blockage warning index exceeds the preset sand blockage threshold range, a warning signal is issued; if the sand blockage warning index does not exceed the preset sand blockage threshold range, it is determined whether the fracturing operation has ended; if the fracturing operation has ended, the warning is stopped.

[0038] The present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements a sand plugging risk warning method for shale gas fracturing construction as described in any of the above technical solutions.

[0039] Compared with the prior art, the beneficial effects of the present invention include: First, the method provided by the present invention, by constructing a real-time oil pressure time series, can analyze and characterize real-time construction oil pressure data, realizing real-time data information mining of oil pressure curves and more significantly exploring the deeper information of oil pressure curves; second, by using a weighted method, the analysis results of oil pressure curve data information are summarized into a sand blockage early warning index, which facilitates visualization processing and subsequent automatic judgment; finally, by using the sand blockage early warning judgment criteria obtained from big data, a real-time judgment can be made on the sand blockage early warning index.

[0040] This invention innovatively combines four calculation methods—oil pressure time slope, oil pressure time slope change rate, real-time oil pressure increment, and fitted oil pressure intercept—to characterize the fluctuation of the oil pressure curve in real time. This allows for multi-dimensional information mining of the real-time oil pressure curve characteristics, avoiding inaccurate warning signals and false alarms caused by an overemphasis on a single factor. Furthermore, this invention uses a weighted method to provide a sand blockage warning index based on the information obtained from mining various fracturing oil pressure curve data, facilitating judgment by on-site construction personnel and enhancing visualization. Combined with specific big data analysis, it provides a judgment range for the sand blockage warning index, enabling automated machine judgment. This provides a new approach to judging sand blockage during multi-stage fracturing operations in shale gas reservoirs, reducing false alarm rates without affecting the accuracy of sand blockage warnings. It offers guidance for shale gas fracturing operations and has strong practicality. Attached Figure Description

[0041] Figure 1 A flowchart illustrating a sand plugging risk warning method for shale gas fracturing operations provided in this embodiment of the invention;

[0042] Figure 2 A flowchart illustrating the sand plugging risk warning method for fracturing operations in well A1 provided in this embodiment of the invention;

[0043] Figure 3(a) is a schematic diagram of the oil pressure time slope results provided in the embodiment of the present invention;

[0044] Figure 3(b) is a schematic diagram of the result of the oil pressure time slope change rate provided in the embodiment of the present invention;

[0045] Figure 3(c) is a schematic diagram of the real-time oil pressure increment results provided by the embodiment of the present invention;

[0046] Figure 3(d) is a schematic diagram of the fitting oil pressure intercept provided in the embodiment of the present invention;

[0047] Figure 3(e) is a schematic diagram of the results of the sand blockage early warning index provided by the embodiment of the present invention;

[0048] Figure 4 This is a schematic diagram of a sand plugging risk warning device for shale gas fracturing construction provided in an embodiment of the present invention. Detailed Implementation

[0049] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0050] This invention proposes a method for early warning of sand plugging risk in shale gas fracturing operations. Figure 1 This is a flowchart illustrating the sand plugging risk early warning method for shale gas fracturing operations, the method comprising:

[0051] Step S101: Obtain real-time oil pressure data and establish a wellbore pressure time series based on the real-time oil pressure data;

[0052] Step S102: Calculate oil pressure characteristic data based on the wellbore pressure time series;

[0053] Step S103: Determine the sand blockage early warning index based on the oil pressure characteristic data;

[0054] Step S104: Determine whether the sand blockage warning index exceeds the preset sand blockage threshold range; if the sand blockage warning index exceeds the preset sand blockage threshold range, issue a warning signal; if the sand blockage warning index does not exceed the preset sand blockage threshold range, determine whether the fracturing operation has ended; if the fracturing operation has ended, stop issuing warnings.

[0055] The method provided in this embodiment firstly constructs a real-time oil pressure time series, enabling analysis and characterization of real-time construction oil pressure data. This achieves real-time data information mining of the oil pressure curve, significantly exploring deeper information within the curve. Secondly, a weighted method is used to summarize the oil pressure curve data analysis results into a sand blockage early warning index, facilitating visualization and subsequent automatic judgment. Finally, a sand blockage early warning judgment criterion obtained from big data allows for real-time judgment of the sand blockage early warning index. This embodiment innovatively characterizes oil pressure curve fluctuations, enabling multi-dimensional information mining of real-time oil pressure curve characteristics. This avoids inaccurate early warning signals and false alarms caused by overly strong single factors. The method uses a weighted method to provide a sand blockage early warning index based on the information mined from various fracturing oil pressure curve data, facilitating judgment by on-site construction personnel and enhancing visualization. Combined with specific big data analysis, a judgment range for the sand blockage early warning index is provided, enabling automatic machine judgment. This provides a new approach for judging sand blockage during multi-stage fracturing operations in shale gas reservoirs. It can not only reduce the false alarm rate of early warning, but also does not affect the accuracy of sand blockage early warning. It can provide guidance for shale gas fracturing construction and has strong practicality.

[0056] Specifically, in step S101, oil pressure data is obtained in real time through the data serial port of the on-site fracturing equipment, and an oil pressure time series is constructed. The specific steps for constructing the real-time oil pressure time series are as follows:

[0057] Extract real-time oil pressure data at the previous n time points: P1, P2, P3, ..., P n According to the corresponding times t1, t2, t3, ..., t n Establish a hydraulic pressure time series.

[0058] In some embodiments, the oil pressure characteristic data in step S102 includes at least the oil pressure time slope, the rate of change of the oil pressure time slope, the real-time oil pressure increment, and the fitted oil pressure intercept.

[0059] The fracturing operation curve is the most important curve in field operations, often directly reflecting the downhole and fracture extension. However, fracturing operations are constantly changing, and the oil pressure curve often fluctuates significantly. Therefore, relying solely on the traditional single-slope method to judge sand blockage often results in inconsistent and abnormal warning indicators. Furthermore, common curve noise reduction methods, such as moving averages and mean methods, excessively reduce the sensitivity of the double logarithmic slope. Therefore, by calculating oil pressure characteristic values ​​such as the oil pressure time slope, the rate of change of the oil pressure time slope, the real-time oil pressure increment, and the fitted oil pressure intercept, information can be mined from multiple dimensions of the real-time oil pressure curve characteristics, avoiding inaccurate warning signals and false alarms caused by an overemphasis on a single factor.

[0060] In some embodiments, the method for calculating the hydraulic time slope includes:

[0061] Based on the oil pressure at each moment in the oil pressure time series, the oil pressure change and time change are determined, and the oil pressure slope is obtained; the calculation formula is:

[0062]

[0063] Where k′ is the hydraulic time slope; P i P represents the current oil pressure. i-1 The oil pressure at time i-1; t i For time i; t i-1 This is the (i-1)th time.

[0064] In some embodiments, the method for calculating the real-time oil pressure increment includes:

[0065] The oil pressure increment is obtained based on the maximum and minimum oil pressure data within a preset time period; the calculation formula is:

[0066] P Z =Max(P) - Min(P)

[0067] Among them, P Z For the oil pressure increment, Max(P) is the maximum oil pressure within a preset time period, and Min(P) is the minimum oil pressure within a preset time period.

[0068] Specifically, in practical applications, a preset time period of 5 seconds is set, containing 5 oil pressure data sampling points. For the oil pressure data within the latest 5 time points, the difference between the maximum and minimum oil pressure is taken as the oil pressure increment, and its expression remains the same:

[0069] P Z =Max(P) - Min(P)

[0070] Among them, P Z For the oil pressure increment, Max(P) is the maximum oil pressure within 5 seconds, and Min(P) is the minimum oil pressure within 5 seconds.

[0071] In some embodiments, the method for calculating the fitted oil pressure intercept includes:

[0072] The least squares method was used to perform univariate linear regression analysis on the oil pressure and time of a predetermined number of consecutive sampling points to obtain the fitted regression curve;

[0073] The fitted oil pressure is obtained based on the fitted regression curve;

[0074] By using the intercept of the fitted oil pressure according to the linear equation, the variation of the fitted oil pressure under different fitted curves is determined.

[0075] Specifically, if the preset number is still 5, then: the least squares method is first used to perform univariate linear regression analysis on the pressure and time of 5 consecutive oil pressure seconds to fit the regression curve; then the intercept of the fitted oil pressure is obtained by using the linear equation to see the change of fitted oil pressure under different fitted curve conditions.

[0076] It should be noted that the specific steps of the least squares method are as follows:

[0077] Let y be m variables x1, x2, ..., xn. m The function has m+1 parameters a0, a1, a2, ..., a m That is: y = f(a0, a1, a2, ..., a m x1, x2, ..., x m );

[0078] There are n sets (n>m) of data (x1, x2, ..., xm) m y i ), i = 1, 2, ..., n. The data (x1, x2, ..., xn) m Substituting into the above formula, we obtain the calculated value. Generally, calculated values With data y i They are not equal, but rather there is a deviation ε. i :

[0079]

[0080] The least squares method aims to minimize the sum of squared deviations, i.e.:

[0081]

[0082] It can be deduced that Q is the parameter a0, a1, a2, ..., a m The function, therefore, should have:

[0083]

[0084] Solve the above equation to find a0, a1, a2, ..., a n Substitute this into the functional expression. Therefore, the curve it represents corresponds to the data (x1, x2, ..., x...). n y i The best fit is found for i = 1, 2, ..., n; after obtaining the fitting equation, the intercept can be obtained to get the fitting oil pressure intercept.

[0085] In some embodiments, the method for calculating the sand blockage early warning index in step S103 includes:

[0086] The weighted method is used to calculate the sand blockage early warning index based on the oil pressure time slope, the rate of change of oil pressure time slope, the real-time oil pressure increment, and the fitted oil pressure intercept; the specific method is as follows:

[0087] Assuming the standardized value of the oil pressure time slope is index B1, the standardized value of the oil pressure time slope change rate is index B2, the standardized value of the oil pressure increment is index B3, and the standardized value of the fitted oil pressure intercept is index B4, then the sand blockage warning index WI is:

[0088] WI = w1B1 + w2B2 + w3B3 + w4B4

[0089] Among them, w i (i = 1, 2, 3, 4) represent the importance of each indicator.

[0090] Specifically, to correlate the above real-time oil pressure analysis results with the sand blockage signal, a weighted method is used to calculate the sand blockage early warning index. It is assumed that the four indicators—oil pressure time slope, oil pressure time slope change rate, real-time oil pressure increment, and fitted oil pressure intercept—are equally important; then:

[0091] WI = 0.25B i (i = 1, 2, 3, 4)

[0092] Of the four indicators, B1, B2, and B3 are positive indicators, and their standardization is as follows:

[0093]

[0094] B4 is a negative indicator, and its standardization process is as follows:

[0095]

[0096] It should be noted that, in practical applications, the comprehensive judgment index based on the calculated sand blockage early warning index is as follows: when the early warning index is 0-0.5, it is considered normal formation fracturing; when it is 0.5-0.62, it is considered low-risk fracturing; and when it is 0.62-1, it is considered sand blockage.

[0097] In some embodiments, the method for determining whether the fracturing operation has ended in step S104 includes:

[0098] Obtain fracturing construction design parameters and fracturing construction status parameters;

[0099] Determine whether the fracturing operation status parameters have reached the standard of the fracturing operation design parameters; if the standard of the design parameters has been reached, then determine that the fracturing operation has ended.

[0100] Specifically, in practical applications, before obtaining real-time oil pressure data, the fracturing construction design parameters are first imported. The construction progress is judged by the fracturing construction design parameters. The algorithm compares the obtained fracturing construction status parameters with the design parameters and can automatically determine whether to stop the warning.

[0101] In some embodiments, the fracturing construction design parameters include fracturing construction parameters such as section length, designed sand injection rate, designed fluid volume, and wellbore diameter. These parameters can be obtained through a fracturing construction design scheme.

[0102] To verify the practical effect of the method provided by this invention, the method of this embodiment was applied to the fourth section of Fuling A1 well for practical effect verification. The construction details of Fuling A1 well are as follows:

[0103] (1) Acid replacement phase

[0104] Well A1 initially drilled to a depth of 9.79m. 3 After adding the isolation fluid, add hydrochloric acid and inject 10.00 ml. 3 The hydrochloric acid pump pressure during application is 32.37-33.75 MPa, and the discharge capacity is 1.8-1.9 m³ / s. 3 / min. After the hydrochloric acid is pumped out, drag-reducing water is injected to wait for acid degradation. After acid degradation, the pumping rate is increased rapidly to break through the formation. The fracturing pressure is 55.43 MPa, and the acid degradation pressure drops from 41.51 MPa to 37.21 MPa.

[0105] (2) Sand plugging stage

[0106] After the pressure stabilizes, add 70 / 140 mesh quartz sand in stages at sand ratios of 3%, 5%, and 7%, and drive the mixture to a depth of 9.84m. 3 The pressure subsequently increased from 61.99 MPa to 74.47 MPa. Sanding was stopped, and after the pressure stabilized, fine sand was injected for grinding. The sand was added sequentially in the following order: 3% sand ratio with drag-reducing water, alternately injected into the wellbore. Then, sand ratios of 3%, 5%, 7%, and 9% were added in stages. The oil pressure decreased from 79.52 MPa to 54.42 MPa, showing a continuous downward trend. Sanding was stopped, and isolation fluid was injected, followed by the addition of 40 / 70 mesh coated quartz sand. After injecting 3% sand ratio with drag-reducing water into the wellbore, the sand ratios of 3%, 5%, 7%, and 9% were added, resulting in a depth of 8.89 m. 3 After stopping sand production and injecting water-blocking and isolating fluid, observe the pressure changes. If there is no significant pressure change, inject medium sand at sand ratios of 10%, 12%, and 14%, for a total depth of 26.44m. 3 After a significant increase in pressure, once the pressure stabilized, medium sand was added at a ratio of 13%, 10%, and 12%, along with drag-reducing water injected into the wellbore. 10.10m of medium sand was then injected. 3 After the pressure surged, sand was stopped. Following the sand stoppage, the pressure increased and the discharge rate decreased, replacing 46.15m of drag-reducing water. 3 The pressure then surged to 95.99 MPa, causing the pump to shut down due to overpressure.

[0107] (3) Unblocking phase

[0108] After sand plugging, on-site venting and spraying were carried out for rectification. 0.2m was observed after venting and spraying. 3 The pump was started at a displacement of / min for trial extrusion. The initial pressure of the venting was 25.32MPa, which dropped to 2.71MPa after a period of time. After the venting outlet was closed, the oil pressure rose to 12.50MPa, and the venting ended.

[0109] After the blowout was completed, test extrusion began. During the process, pressure changes were observed and the displacement was increased. 191.27m of drag-reducing water was injected. 3 The reagent was successfully applied, reducing emissions by 3.08 mg / L of potassium chloride. 3 To reduce surface tension and promote reverse discharge, 60.29m of drag-reducing water-based barrier fluid was then injected. 3 The pump was then stopped to complete the fracturing operation.

[0110] Judging from the construction process, the sand blockage started about 155 minutes after the start of construction and the pump was stopped 160 minutes later, lasting 5 minutes. It can be seen that the sand blockage occurred very suddenly and required an experienced on-site engineer to diagnose and direct the operation. Otherwise, the consequences would be unimaginable.

[0111] like Figure 2 As shown, Figure 2 This is a schematic diagram of the specific sand blockage risk early warning process for this application. Taking the sand blockage in well A1 within 8 minutes as an example according to the method of this invention, it should be noted that the calculation assumes that the four indicators—oil pressure time slope, oil pressure time slope change rate, real-time oil pressure increment, and fitted oil pressure intercept—are equally important; that is: WI = 0.25B i (i = 1, 2, 3, 4).

[0112] First, the oil pressure time slope relationship is obtained as shown in Figure 3(a); the oil pressure time slope change rate is shown in Figure 3(b); the oil pressure increment is shown in Figure 3(c); and the fitted oil pressure intercept is shown in Figure 3(d). After standardizing the four indicators, they are substituted into the sand blockage early warning index formula, and the calculation results are shown in Figure 3(e). Among them, the oil pressure increment and the fitted oil pressure intercept can effectively reduce noise in the double logarithmic slope curve of oil pressure time, and do not affect its sensitivity in the sand blockage section. The slope change rate can enhance the sensitivity of sand blockage during the sand blockage process. Combining the four indicators yields a sand blockage early warning index that both amplifies the sensitivity of the sand blockage section and reduces the abnormal warning. From Figures 3(a)-3(e) It can be clearly seen that within eight minutes of sand blockage, the judgment time for manual identification of sand blockage on site is about 10-15 seconds, while the method of this application can reduce this time to 24-48 seconds.

[0113] This embodiment also provides a sand plugging risk early warning device for shale gas fracturing operations, such as... Figure 4As shown, the sand plugging risk early warning device 400 for shale gas fracturing includes:

[0114] Data acquisition module 401 is used to acquire real-time oil pressure data and establish a wellbore pressure time series based on the real-time oil pressure data;

[0115] Analysis module 402 is used to calculate oil pressure characteristic data based on the wellbore pressure time series;

[0116] Calculation module 403 is used to determine the sand blockage early warning index based on the oil pressure characteristic data;

[0117] The judgment module 404 is used to determine whether the sand blockage warning index exceeds the preset sand blockage threshold range; if the sand blockage warning index exceeds the preset sand blockage threshold range, a warning signal is issued; if the sand blockage warning index does not exceed the preset sand blockage threshold range, it is determined whether the fracturing operation has ended; if the fracturing operation has ended, the warning is stopped.

[0118] This embodiment also provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements a deep learning-based method for predicting urban traffic carbon emissions as described in any of the above technical solutions.

[0119] The computer-readable storage medium and computing device provided in the above embodiments of the present invention can be implemented with reference to the content specifically described in the present invention for implementing the deep learning-based urban traffic carbon emission prediction method, and have similar beneficial effects to the deep learning-based urban traffic carbon emission prediction method described above, which will not be repeated here.

[0120] The present invention provides a method and device for sand plugging risk early warning in shale gas fracturing operations. First, by constructing a real-time oil pressure time series, the real-time construction oil pressure data can be analyzed and characterized, realizing real-time data information mining of the oil pressure curve and more significantly exploring the deeper information of the oil pressure curve. Second, the analysis results of the oil pressure curve data information are summarized into a sand plugging early warning index through a weighted method, which facilitates visualization processing and subsequent automatic judgment. Finally, based on the sand plugging early warning index and corresponding judgment indicators, a judgment can be made on whether an alarm has occurred.

[0121] This invention innovatively combines four calculation methods—oil pressure time slope, oil pressure time slope change rate, real-time oil pressure increment, and fitted oil pressure intercept—to characterize the fluctuation of the oil pressure curve in real time. This allows for multi-dimensional information mining of real-time oil pressure curve characteristics, avoiding inaccurate warning signals and false alarms caused by an overemphasis on a single factor. Furthermore, this invention uses a weighted method to provide a sand blockage warning index based on the information mined from various fracturing oil pressure curve data, facilitating judgment by on-site construction personnel and enhancing visualization. Combined with specific big data analysis, it provides a judgment range for the sand blockage warning index, enabling automated machine judgment. This provides a new approach to judging sand blockage during multi-stage fracturing operations in shale gas reservoirs, reducing false alarm rates without compromising the accuracy of sand blockage warnings. It offers guidance for shale gas fracturing operations and has strong practicality.

[0122] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for early warning of sand plugging risk in shale gas fracturing operations, characterized in that, The method includes: Acquire real-time oil pressure data and establish a wellbore pressure time series based on the real-time oil pressure data; Oil pressure characteristic data are calculated based on the wellbore pressure time series; the oil pressure characteristic data includes at least the oil pressure time slope, the rate of change of the oil pressure time slope, the real-time oil pressure increment, and the fitted oil pressure intercept; The sand blockage early warning index is determined based on the oil pressure characteristic data; the calculation method for the sand blockage early warning index includes: The weighted method is used to calculate the sand blockage early warning index based on the oil pressure time slope, the rate of change of oil pressure time slope, the real-time oil pressure increment, and the fitted oil pressure intercept; the specific method is as follows: Assuming the standardized value of the hydraulic pressure time slope is the index The standardized value of the rate of change of the hydraulic pressure time slope is an indicator. Standardized value of oil pressure increment is the indicator The standardized value of the fitted oil pressure intercept is the index. The sand blockage warning index for: in, These represent the relative importance of each indicator; Determine whether the sand blockage warning index exceeds the preset sand blockage threshold range; if the sand blockage warning index exceeds the preset sand blockage threshold range, issue a warning signal; if the sand blockage warning index does not exceed the preset sand blockage threshold range, determine whether the fracturing operation has ended; if the fracturing operation has ended, stop issuing warnings.

2. The method for early warning of sand plugging risk in shale gas fracturing construction according to claim 1, characterized in that, The method for calculating the hydraulic time slope includes: The oil pressure change and time change are determined based on the oil pressure at each moment in the oil pressure time series, and the oil pressure slope is obtained; the calculation formula is: in, The slope of the hydraulic pressure time; Current oil pressure; for Oil pressure at any given time; For the first time; For the first time.

3. The method for early warning of sand plugging risk in shale gas fracturing construction according to claim 1, characterized in that, The method for calculating the real-time oil pressure increment includes: The oil pressure increment is obtained based on the maximum and minimum oil pressure data within a preset time period; the calculation formula is: in, For oil pressure increment, The maximum oil pressure within a preset time period. This refers to the minimum oil pressure within a preset time period.

4. The method for early warning of sand plugging risk in shale gas fracturing construction according to claim 1, characterized in that, The method for calculating the fitted oil pressure intercept includes: The least squares method was used to perform univariate linear regression analysis on the oil pressure and time of a continuous preset number of sampling points to obtain the fitted regression curve; The fitted oil pressure is obtained based on the fitted regression curve; By using the intercept of the fitted oil pressure according to the linear equation, the variation of the fitted oil pressure under different fitted curves is determined.

5. The method for early warning of sand plugging risk in shale gas fracturing construction according to claim 1, characterized in that, The methods for determining whether fracturing operations have ended include: Obtain fracturing construction design parameters and fracturing construction status parameters; Determine whether the fracturing operation status parameters have reached the standard of the fracturing operation design parameters; if the standard of the fracturing operation design parameters has been reached, then determine that the fracturing operation has ended.

6. The method for early warning of sand plugging risk in shale gas fracturing construction according to claim 5, characterized in that, The fracturing construction design parameters include: section length, design sand addition amount, design fluid volume, and wellbore diameter.

7. A sand plugging risk early warning device for shale gas fracturing operations, characterized in that, include: The data acquisition module is used to acquire real-time oil pressure data and establish a wellbore pressure time series based on the real-time oil pressure data; The analysis module is used to calculate oil pressure characteristic data based on the wellbore pressure time series; the oil pressure characteristic data includes at least the oil pressure time slope, the rate of change of the oil pressure time slope, the real-time oil pressure increment, and the fitted oil pressure intercept. The calculation module is used to determine the sand blockage early warning index based on the oil pressure characteristic data; The method for calculating the sand blockage early warning index includes: The weighted method is used to calculate the sand blockage early warning index based on the oil pressure time slope, the rate of change of oil pressure time slope, the real-time oil pressure increment, and the fitted oil pressure intercept; the specific method is as follows: Assuming the standardized value of the hydraulic pressure time slope is the index The standardized value of the rate of change of the hydraulic pressure time slope is an indicator. Standardized value of oil pressure increment is the indicator The standardized value of the fitted oil pressure intercept is the index. The sand blockage warning index for: in, These represent the relative importance of each indicator; The judgment module is used to determine whether the sand blockage warning index exceeds the preset sand blockage threshold range; if the sand blockage warning index exceeds the preset sand blockage threshold range, a warning signal is issued; if the sand blockage warning index does not exceed the preset sand blockage threshold range, it is determined whether the fracturing operation has ended; if the fracturing operation has ended, the warning is stopped.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which, when executed by a processor, implements a sand plugging risk warning method for shale gas fracturing construction as described in any one of claims 1-6.

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