Long-hole hydraulic fracturing hole water pressure monitoring device and fracturing effect evaluation method

Abstract

The application discloses a long borehole hydraulic fracturing in-hole water pressure monitoring device and a fracturing effect evaluation method. The long borehole hydraulic fracturing in-hole water pressure monitoring device comprises a rod body, a base and a detection component, the middle part of the rod body is provided with a flow channel; the base is arranged in the flow channel and connected with the inner wall of the rod body, the outer side of the base and the inner wall of the rod body are provided with a flow gap, the base is provided with a detection cavity, the sidewall of the rod body is provided with a communication hole, the communication hole is communicated with the detection cavity so that the fluid outside the rod body can flow into the detection cavity; the detection component is arranged in the flow channel and connected with the base, and the detection end of the detection component extends into the detection cavity to detect the water pressure in the detection cavity. The embodiment can accurately measure the water pressure of the annular area outside the pipe string of the hydraulic fracturing section, the measurement data can be obtained in real time and has high precision, the fracture expansion condition can be accurately evaluated and judged, the practicability is good, and the fluid conveying in the pipe string is not affected.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic fracturing technology, specifically relating to a device for monitoring water pressure inside a long borehole in hydraulic fracturing and a method for evaluating fracturing effect. Background Technology

[0002] Long-bore hydraulic fracturing technology has been widely applied in coal mines for underground gas extraction, rockburst prevention, and hard roof weakening. By creating a large-scale, interconnected network of fractures in the coal seam / rock strata, hydraulic fracturing improves gas desorption efficiency or reduces stress concentration. Long-bore hydraulic fracturing can replace traditional dense short-bore drilling (which is inefficient and costly), achieving "one borehole with multiple fractures and long-distance pressure relief."

[0003] In related technologies, the built-in sensors can only monitor the fluid pressure inside the fracturing tubing string. Surface fracturing wells are casing wells with sealable wellheads, allowing for the installation of annular pressure gauges at the wellhead. However, the difference between long boreholes in tunnels and surface fracturing wells is that in-hole casing cannot be installed, and the borehole opening of long boreholes is an open opening, making it impossible to install an annular pressure gauge. Therefore, monitoring of annular pressure inside the borehole cannot be achieved. Summary of the Invention

[0004] This invention is based on the inventor's discoveries and understanding of the following facts and problems:

[0005] The inventors recognized that the built-in sensors in the related technologies can only monitor the fluid pressure inside the fracturing string and cannot obtain the true formation pressure in the annulus outside the string. The pressure difference between the fluid pressure inside the fracturing string and the true annulus pressure outside the string can reach 5-15 MPa, which can easily lead to distortion in the judgment of fracture propagation and make it difficult to effectively evaluate the fracturing effect.

[0006] The present invention aims to at least partially solve one of the technical problems in the related art.

[0007] Therefore, embodiments of the present invention propose a long borehole hydraulic fracturing borehole water pressure monitoring device that can measure the annular pressure outside the tubing string in real time and accurately.

[0008] The embodiments of the present invention also propose a method for evaluating fracturing effect.

[0009] The water pressure monitoring device for long-bore hydraulic fracturing boreholes according to an embodiment of the present invention includes:

[0010] A rod body, wherein the middle part of the rod body has a flow channel;

[0011] A base is disposed within the flow channel and connected to the inner wall of the rod body. A flow gap exists between the outer side of the base and the inner wall of the rod body. The base has a detection cavity. A connecting hole is provided on the side wall of the rod body, and the connecting hole communicates with the detection cavity so that fluid from the outer side of the rod body can flow into the detection cavity.

[0012] A detection component is disposed within the flow channel and connected to the base. The detection end of the detection component extends into the detection cavity to detect the water pressure within the detection cavity.

[0013] The water pressure monitoring device for long borehole hydraulic fracturing according to this invention can be connected between adjacent drill pipes and accurately placed in the hydraulic fracturing section. During the hydraulic fracturing process, water in the annulus outside the tubing can enter the detection chamber, thereby accurately measuring the water pressure in the annulus outside the tubing in the hydraulic fracturing section. The measurement data can be acquired in real time with high accuracy, which helps to accurately evaluate and judge the fracture propagation. It has good practicality and does not affect the transport of fluid inside the tubing.

[0014] In some embodiments, a filter element is further included, the filter element being disposed at the end of the communicating hole away from the detection cavity.

[0015] In some embodiments, the rod body has a groove circumferentially arranged in the communicating hole, the filter element is disposed in the groove, and the filter element is fixedly connected to the rod body.

[0016] The filter element is recessed into the outer wall surface of the rod body, or the outer end of the filter element is flush with the outer wall surface of the rod body.

[0017] In some embodiments, the first end of the rod body has a first connecting portion, the second end of the rod body has a second connecting portion, and the rod body is connected to an adjacent drill rod through the first connecting portion and the second connecting portion;

[0018] And / or, there are multiple connecting holes, and all of the multiple connecting holes are connected to the detection cavity.

[0019] In some embodiments, the detection component includes a water pressure sensor and a battery connected together.

[0020] In some embodiments, the base is provided with a connection port, and the water pressure sensor is connected to the connection port so that the detection end of the water pressure sensor is located in the detection cavity, and the detection cavity is isolated from the flow channel of the rod body.

[0021] This invention provides a method for evaluating fracturing effectiveness, including:

[0022] The water pressure monitoring device for hydraulic fracturing in long boreholes as described in any of the above embodiments is connected between two adjacent drill rods and placed at the hydraulic fracturing section of the borehole.

[0023] Obtain the pressure data of the annular water pressure in the hydraulic fracturing section, and perform noise reduction processing on the pressure data;

[0024] The time-domain and frequency-domain characteristics of the pressure data are obtained, and the peak characteristics of energy in the time-domain and frequency-domain are recorded as crack events;

[0025] Energy peaks were monitored, and the number of fracture events and total energy of each hydraulic fracturing stage were obtained.

[0026] Determine the complexity of fractures in different hydraulic fracturing stages.

[0027] In some embodiments, the step of obtaining the time-domain and frequency-domain characteristics of the pressure data includes:

[0028] Based on formula The pressure data is subjected to S-transform processing;

[0029] In the formula, P(t) represents the pressure data, τ represents the event location parameter, and f represents the frequency parameter. It is a frequency-dependent Gaussian window function, S(τ,f) is the S-transform function, and e -i2πft This is a complex exponential oscillation term used for local frequency analysis, where dt is the integral over time t.

[0030] The time-domain and frequency-domain characteristics of the pressure data are obtained based on the S-transform.

[0031] In some embodiments, the step of monitoring energy peaks and obtaining the number of fracture events and the total energy of each hydraulic fracturing stage includes:

[0032] Based on formula E th =μ(E)+3σ(E) to obtain the energy threshold of the fracture event;

[0033] In the formula, E represents energy, and E = ∑|S(τ,f)| 2 E th The energy threshold, μ(E) represents dynamic homogeneity, and σ(E) represents dynamic standard deviation; μ(E) is obtained by the arithmetic mean of the energy sequence within the sliding window, and σ(E) is obtained by the standard deviation of the energy sequence within the sliding window;

[0034] Criteria for determining the energy peak point:

[0035] Fracture events are identified by energy peak values, and the number n of fracture events in each hydraulic fracturing stage is recorded. iTotal energy of the event E i E i Let be the total energy value of the i-th event.

[0036] In some embodiments, the step of determining the fracture complexity of different hydraulic fracturing stages includes:

[0037] Based on formula and formula The number of crack events n i Total energy of the event E i Normalization process, where: N f N is the number factor for crack events. f E is the energy factor for crack events. min E represents the minimum energy of the event. max This represents the maximum value of the event energy.

[0038] Based on the formula FCI=αN f +βE f The fracture complexity index FCI is obtained, where α and β are weighting coefficients, and the FCI value range is [0, 1].

[0039] The complexity of fractures in different hydraulic fracturing stages is evaluated based on the FCI of different hydraulic fracturing stages. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of a long borehole hydraulic fracturing borehole water pressure monitoring device according to an embodiment of the present invention.

[0041] Figure 2 This is a schematic diagram from another perspective of the water pressure monitoring device inside the long borehole hydraulic fracturing hole according to an embodiment of the present invention.

[0042] Figure 3 This is a side view of the water pressure monitoring device inside the long borehole hydraulic fracturing hole according to an embodiment of the present invention.

[0043] Figure 4 yes Figure 3 A schematic diagram of the AA direction.

[0044] Figure 5 yes Figure 3 A schematic diagram of the BB direction.

[0045] Figure 6 This is a schematic diagram of the fracturing effect evaluation method according to an embodiment of the present invention.

[0046] Figure 7 It is pressure data obtained by a hydraulic fracturing borehole pressure monitoring device for long boreholes.

[0047] Figure label:

[0048] 100. Water pressure monitoring device inside long-bore hydraulic fracturing holes;

[0049] 1. Rod body; 11. Flow channel; 12. Connecting hole; 13. First connecting part; 14. Second connecting part; 15. Flow gap; 16. Settling groove;

[0050] 2. Base; 21. Detection chamber;

[0051] 3. Detection components; 31. Hydraulic sensor; 311. Detection end; 32. Battery;

[0052] 4. Filter components. Detailed Implementation

[0053] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0054] See Figures 1 to 5 The water pressure monitoring device 100 for hydraulic fracturing in long boreholes according to an embodiment of the present invention includes a rod body 1, a base 2 and a detection component 3.

[0055] In this embodiment, the rod body 1 can be connected between two adjacent drill pipes in a hydraulic fracturing string, and the rod body 1 has a flow channel 11 in the middle. Thus, the fluid in the hydraulic fracturing string can pass through the flow channel 11 without affecting the fluid injection during hydraulic fracturing.

[0056] In this embodiment, the base 2 is disposed in the flow channel 11 and is connected to the inner wall of the rod body 1. There is a flow gap 15 between the outer side of the base 2 and the inner wall of the rod body 1. The base 2 has a detection cavity 21. A connecting hole 12 is provided on the side wall of the rod body 1. The connecting hole 12 is connected to the detection cavity 21 so that the fluid on the outer side of the rod body 1 can flow into the detection cavity 21.

[0057] The flow gap 15 ensures the normal and stable flow of fluid in the hydraulic fracturing string. The base 2 can be integrally formed with the rod body 1, or it can be connected by detachable connection methods such as bolts, threads, and clips.

[0058] The base 2 can be generally cylindrical, with its outer diameter smaller than the inner diameter of the flow channel 11. This allows a flow gap 15 to be defined between the outer wall of the base 2 and the inner wall of the flow channel 11. The connecting hole 12 connects the external space of the rod body 1 and the detection chamber 21, allowing water from the annular region of the hydraulic fracturing section to enter the detection chamber 21 during hydraulic fracturing.

[0059] The detection component 3 is located in the flow channel 11 and is connected to the base 2. The detection end 311 of the detection component 3 extends into the detection chamber 21 to detect the water pressure in the detection chamber 21.

[0060] In this embodiment, the detection chamber 21 and the flow channel 11 within the rod body 1 are independent of each other and do not affect each other, thereby ensuring that the detection data acquired by the detection component 3 is more reliable and accurate. The detection component 3 can be embedded in the base 2 or detachably connected to the base 2 via threads. It is understood that although the detection component 3 is located within the flow channel 11, it does not block the flow channel 11, and the fluid at the inlet end of the rod body 1 can flow to the outlet end of the rod body 1 through the outer peripheral space of the detection component 3.

[0061] The long borehole hydraulic fracturing in-hole water pressure monitoring device 100 of this invention can be connected between adjacent drill rods and accurately placed in the hydraulic fracturing section. During the hydraulic fracturing process, water in the annulus region outside the tubing can enter the detection chamber 21, thereby accurately measuring the water pressure in the annulus region outside the tubing in the hydraulic fracturing section. The measurement data can be acquired in real time with high accuracy, which helps to accurately evaluate and judge the fracture propagation. It has good practicality and does not affect the transport of fluid inside the tubing.

[0062] In some embodiments, the water pressure monitoring device 100 for long-bore hydraulic fracturing holes further includes a filter element 4, which is disposed at the end of the connecting hole 12 away from the detection chamber 21. The filter element 4 can be a perforated plate. The filter element 4 does not obstruct the flow of water into the connecting hole 12, and at the same time prevents small particles of impurities from entering the connecting hole 12, thereby avoiding impurities from clogging the connecting hole 12 or entering the detection chamber 21 and contacting the detection component 3, which could lead to errors in the detection data of the detection component 3 or damage to the detection component 3. In this embodiment, the filter element 4 can improve the stability of the equipment and ensure that the equipment can stably monitor the water pressure in the annulus area of ​​the hydraulic fracturing section for a long period of time.

[0063] Furthermore, the rod body 1 has a groove 16 around the connecting hole 12, the filter element 4 is disposed in the groove 16, the filter element 4 is fixedly connected to the rod body 1, the filter element 4 is recessed in the outer wall surface of the rod body 1, or the outer end of the filter element 4 is flush with the outer wall surface of the rod body 1.

[0064] This avoids the filter element 4 protruding beyond the outer wall of the rod body 1, and prevents the filter element 4 from directly contacting the rock wall, which could lead to the mesh being blocked or the filter element 4 being squeezed and deformed. This embodiment can realize the installation of the filter element 4 and ensure the normal and stable operation of the filter element 4.

[0065] Optionally, the settling tank 16 is a circular settling tank 16, and the filter element 4 is a circular plate-shaped perforated plate. After the filter element 4 is placed in the settling tank 16, it can be fixed to the rod body 1 with screws. This facilitates disassembly, replacement, and maintenance, and improves practicality. It also avoids the need to replace the entire rod body 1 after the filter element 4 is damaged, reducing maintenance costs.

[0066] In some embodiments, there are multiple connecting holes 12, all of which are connected to the detection chamber 21. For example, two, three, four or more connecting holes 12 are provided on the rod body 1. The multiple connecting holes 12 are used to ensure that the fluid outside the rod body 1 can smoothly enter the detection chamber 21, and to avoid inaccurate detection data caused by gas residue in the detection chamber 21.

[0067] In this embodiment, the base 2 and the rod body 1 are connected together by two symmetrically arranged connecting plates, so the connecting hole 12 can be set on the corresponding connecting plate.

[0068] The detection end 311 of the detection component 3 in this embodiment can fill most or all of the detection cavity 21. The connecting hole 12 corresponds to the detection end 311, thereby enabling more effective acquisition of the water pressure on the outside of the rod body 1.

[0069] In some embodiments, the first end of the rod body 1 has a first connecting portion 13, and the second end of the rod body 1 has a second connecting portion 14. The rod body 1 is connected to an adjacent drill pipe through the first connecting portion 13 and the second connecting portion 14. The first connecting portion 13 can be a male thread, and the second connecting portion 14 can be a female thread. The male and female threads are the same as the male and female threads at both ends of the drill pipe, thereby allowing it to match the drill pipe. The rod body 1 is connected using the connection method of adjacent drill pipes, which provides strong versatility and better practicality.

[0070] In some embodiments, the detection component 3 includes a water pressure sensor and a battery 32 connected together. The battery 32 powers the water pressure sensor. The base 2, water pressure sensor, and battery 32 can be arranged and connected sequentially along the axial direction of the rod body 1, thereby ensuring sufficient space between the outer wall surface of the base 2, water pressure sensor, and battery 32 and the inner wall surface of the flow channel 11 to facilitate the passage of fluid in the fracturing string through the rod body 1. The water pressure sensor and battery 32 can be fixed together by a housing, ensuring the sealing of the battery 32.

[0071] Furthermore, the base 2 is provided with a connection port, and the water pressure sensor is connected to the connection port so that the detection end 311 of the water pressure sensor is located inside the detection cavity 21, and the detection cavity 21 is isolated from the flow channel 11 of the rod body 1. The base 2 is provided with a connection port facing one end of the rod body 1 along the axial direction, and the connection port communicates with the detection cavity 21. The water pressure sensor is connected to the connection port, and the detection end 311 can be located inside the detection cavity 21. The connection port can be provided with an internal thread, and the water pressure sensor is connected to the connection port by the thread, which is convenient for disassembly and subsequent maintenance and replacement, and improves practicality.

[0072] This invention, through the long borehole hydraulic fracturing borehole water pressure monitoring device 100, for the first time directly monitors the real water pressure in the annulus outside the tubing string in an open long borehole in a roadway. This solves the problem that the built-in sensors in related technologies can only measure the internal pressure of the tubing string (with an error of 5-15 MPa), avoids misjudgment of fracture propagation due to pressure data distortion, and provides more reliable data support for the fracturing process.

[0073] See Figure 6 This invention provides a method for evaluating fracturing effectiveness, comprising:

[0074] S101. Connect the long borehole hydraulic fracturing in-hole water pressure monitoring device as described in any of the above embodiments between two adjacent drill pipes and place it at the hydraulic fracturing section of the borehole. After fracturing one hydraulic fracturing section, by dragging the fracturing string, the long borehole hydraulic fracturing in-hole water pressure monitoring device can be simultaneously moved to the next hydraulic fracturing section to collect pressure data for the next hydraulic fracturing section, until all fracturing sections are completed.

[0075] S102. Obtain the corresponding annular water pressure data of the hydraulic fracturing section and perform noise reduction processing on the pressure data. This embodiment can accurately obtain the annular water pressure data outside the fracturing string of the hydraulic fracturing section. The data can reliably reflect the pressure borne by the formation during fracturing, and more information such as the fracture propagation time can be obtained based on the changes in the pressure data.

[0076] This embodiment filters and reduces noise in the pressure data, eliminating the influence of other operating conditions on the borehole water pressure during hydraulic fracturing and improving data reliability. This removes noise and makes it easier to extract specific data.

[0077] S103. Obtain the time-domain and frequency-domain characteristics of the pressure data, and record the peak characteristics of energy in the time and frequency domains as crack events. This allows us to obtain information on crack propagation.

[0078] S104. Monitor energy peaks and obtain the number of fracture events and total energy of each hydraulic fracturing segment.

[0079] S105. Determine the fracture complexity of different hydraulic fracturing sections. This allows for quantitative assessment of the fracture network, accurate analysis of the fracture complexity of different fracturing sections, and evaluation of the fracturing effect of each section. This provides better guidance for hydraulic fracturing and enables a more reliable evaluation of the post-fracturing rockburst control and hard roof weakening effects, thereby improving construction safety.

[0080] The following describes some specific embodiments of the present invention.

[0081] See Figure 6 and Figure 7 A method for evaluating fracturing effectiveness, comprising:

[0082] S101. Connect the long borehole hydraulic fracturing in-hole water pressure monitoring device as described in any of the above embodiments between two adjacent drill pipes and place it at the hydraulic fracturing section of the borehole. After fracturing one hydraulic fracturing section, by dragging the fracturing string, the long borehole hydraulic fracturing in-hole water pressure monitoring device can be simultaneously moved to the next hydraulic fracturing section to collect pressure data for the next hydraulic fracturing section, until all fracturing sections are completed.

[0083] S102. Obtain the corresponding annular water pressure data of the hydraulic fracturing section and perform noise reduction processing on the pressure data. This embodiment can accurately obtain the annular water pressure data outside the fracturing string of the hydraulic fracturing section. The data can reliably reflect the pressure borne by the formation during fracturing, and more information such as the fracture propagation time can be obtained based on the changes in the pressure data.

[0084] This embodiment filters and reduces noise in the pressure data, eliminating the influence of other operating conditions on the borehole water pressure during hydraulic fracturing and improving data reliability. This removes noise and makes it easier to extract specific data.

[0085] S103. Obtain the time-domain and frequency-domain characteristics of the pressure data, and record the peak characteristics of energy in the time and frequency domains as crack events. This allows us to obtain information on crack propagation.

[0086] Specifically, based on the formula Perform S-transform processing on the pressure data;

[0087] In the formula, P(t) represents the pressure data, τ represents the event location parameter, and f represents the frequency parameter. It is a frequency-dependent Gaussian window function, S(τ,f) is the S-transform function, and e -i2πft This is a complex exponential oscillation term used for local frequency analysis, where dt is the integral over time t.

[0088] The time-domain and frequency-domain characteristics of the pressure data are obtained based on the S-transform.

[0089] S104. Monitor energy peaks and obtain the number of fracture events and total energy of each hydraulic fracturing segment.

[0090] Specifically, based on formula E th =μ(E)+3σ(E) to obtain the energy threshold of the fracture event;

[0091] In the formula, E represents energy, and E = ∑|S(τ, f)| 2 E th The energy threshold, μ(E) represents dynamic homogeneity, and σ(E) represents dynamic standard deviation. μ(E) is obtained by the arithmetic mean of the energy sequence within the sliding window, and σ(E) is obtained by the standard deviation of the energy sequence within the sliding window.

[0092] Criteria for determining the energy peak point:

[0093] In the above formula, The first derivative of energy E with respect to time t is zero. For energy E to have a second derivative with respect to time t that is less than zero, E > E th The energy must be greater than the energy threshold. Based on these criteria, it can be determined whether an event is a fracture event.

[0094] After identifying fracture events based on energy peak values, record the number n of fracture events in each hydraulic fracturing stage. i Total energy of the event E i E i Let be the total energy value of the i-th event.

[0095] S105. Determine the fracture complexity of different hydraulic fracturing sections. This allows for quantitative assessment of the fracture network, accurate analysis of the fracture complexity of different fracturing sections, and evaluation of the fracturing effect of each section. This provides better guidance for hydraulic fracturing and enables a more reliable evaluation of the post-fracturing rockburst control and hard roof weakening effects, thereby improving construction safety.

[0096] Specifically, based on the formula and formula The number of crack events n i Total energy of the event E i Normalization process, where: N f E is the number of crack events. f E is the energy factor for crack events. min E represents the minimum energy of the event. max This represents the maximum value of the event energy.

[0097] Based on the formula FCI=αN f +βE f The fracture complexity index FCI is obtained, where α and β are weighting coefficients, and the FCI value range is [0, 1].

[0098] The complexity of fractures in different hydraulic fracturing stages is evaluated based on the FCI (Fracturing Intensity Index) of each stage. This embodiment uses the FCI calculated for different stages to evaluate the fracture complexity; a higher relative FCI value between different stages indicates greater fracture complexity.

[0099] This invention proposes a fracture complexity index (FCI), which, based on annular water pressure data, achieves quantitative evaluation of fracture networks through noise reduction processing, S-transform time-frequency analysis, dynamic threshold event identification, and normalization calculation (event number factor + energy factor).

[0100] The embodiments of the present invention determine crack events by transforming pressure data into the time-frequency domain to obtain energy results, which is more accurate and reliable than simply judging the pressure slope value.

[0101] Example 1:

[0102] During hydraulic fracturing of long boreholes in a roadway, the hydraulic pressure monitoring device for long boreholes in this embodiment is connected to the tubing string at the top and bottom and inserted into the borehole together. This allows for the measurement of the annular pressure at the hydraulic fracturing point. The pressure monitoring results are as follows: Figure 7 As shown.

[0103] The above data were denoised, and the crack events and crack energies were calculated, as shown in Table 1:

[0104] Table 1. Calculation results of fracture events and fracture energy.

[0105]

[0106] Based on the above parameters, the calculated crack event quantity factor and energy factor are as follows:

[0107]

[0108] If α and β are both 0.5, then FCI = 0.497.

[0109] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0110] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0111] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0112] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0113] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0114] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for evaluating fracturing effect, characterized in that, A method for evaluating fracturing effectiveness using a long-bore hydraulic fracturing in-hole water pressure monitoring device, wherein the long-bore hydraulic fracturing in-hole water pressure monitoring device includes: A rod body, wherein the middle part of the rod body has a flow channel; A base is disposed within the flow channel and connected to the inner wall of the rod body. A flow gap exists between the outer side of the base and the inner wall of the rod body. The base has a detection cavity. A connecting hole is provided on the side wall of the rod body, and the connecting hole communicates with the detection cavity so that fluid from the outer side of the rod body can flow into the detection cavity. A detection component is disposed within the flow channel and connected to the base. The detection end of the detection component extends into the detection chamber to detect the water pressure within the detection chamber. The fracturing effect evaluation method includes: The water pressure monitoring device for the long borehole hydraulic fracturing is connected between two adjacent drill rods and placed at the hydraulic fracturing section of the borehole. Obtain the pressure data of the annular water pressure in the hydraulic fracturing section, and perform noise reduction processing on the pressure data; The time-domain and frequency-domain characteristics of the pressure data are obtained, and the peak characteristics of energy in the time-domain and frequency-domain are recorded as fracture events. Energy peaks were monitored, and the number of fracture events and total energy of each hydraulic fracturing stage were obtained. Determine the complexity of fractures in different hydraulic fracturing stages; The steps to obtain the time-domain and frequency-domain features of the pressure data include: Based on formula The pressure data is subjected to S-transform processing; In the formula, For stress data, Indicates the event location parameters, Indicates frequency parameters, It is a frequency-dependent Gaussian window function. The S-transform function, This is a complex exponential oscillation term, used for local frequency analysis. This is the integral over time t; The time-domain and frequency-domain characteristics of the pressure data are obtained based on the S-transform. The steps involve monitoring energy peaks and obtaining the number of fracture events and total energy of each hydraulic fracturing stage, including: Based on formula Obtain the energy threshold of the fracture event; In the formula, For energy, , Energy threshold It is a dynamic mean. For dynamic standard deviation; It is obtained by the arithmetic mean of the energy sequences within the sliding window. It is obtained by the standard deviation of the energy sequence within the sliding window; Criteria for determining the energy peak point: ; Fracture events are identified by energy peak values, and the number of fracture events in each hydraulic fracturing stage is recorded. Total energy of events , For the first The total energy value of each event; The steps for determining the fracture complexity of different hydraulic fracturing stages include: Based on formula and formula The number of fracture events Total energy of the event Normalization treatment, where: The number of fracture events is a factor. Energy factor for fracture events. This represents the minimum energy of the event. This represents the maximum value of the event energy. Based on formula Obtaining the fracture complexity index In the formula, , These are the weighting coefficients. The value range is [0, 1]; Based on different hydraulic fracturing stages To evaluate the fracture complexity of different fracturing sections.

2. The fracturing effect evaluation method according to claim 1, characterized in that, It also includes a filter element, which is disposed at the end of the communicating hole away from the detection cavity.

3. The fracturing effect evaluation method according to claim 2, characterized in that, The rod body has a groove around the circumference of the connecting hole, the filter element is disposed in the groove, and the filter element is fixedly connected to the rod body. The filter element is recessed into the outer wall surface of the rod body, or the outer end of the filter element is flush with the outer wall surface of the rod body.

4. The fracturing effect evaluation method according to claim 1, characterized in that, The first end of the rod body has a first connecting part, and the second end of the rod body has a second connecting part. The rod body is connected to the adjacent drill rod through the first connecting part and the second connecting part. And / or, there are multiple connecting holes, and all of the multiple connecting holes are connected to the detection cavity.

5. The fracturing effect evaluation method according to claim 1, characterized in that, The detection component includes a water pressure sensor and a battery connected together.

6. The fracturing effect evaluation method according to claim 5, characterized in that, The base is provided with a connection port, and the water pressure sensor is connected to the connection port so that the detection end of the water pressure sensor is located in the detection cavity, and the detection cavity is isolated from the flow channel of the rod body.

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