Calibration method and device for sector cement bond logging instrument based on theoretical research

Abstract

The application discloses a sector cementing logging instrument calibration method and device based on theoretical research, which comprises numerical simulation based on wellbore wave theory, indoor calibration method and calibration steps. Through numerical simulation and waveform comparison, the influence of instrument eccentricity on the amplitude of casing wave is analyzed, the influence law of instrument eccentricity on the amplitude of sector signal is found, and an 8-point rotation method is proposed to calibrate the sector instrument indoors. The waveform amplitude curve received by the 2ft eight-sector waveform receiving source on the calibration instrument is collected and recorded, and after the calibration instrument rotates for one round, whether the maximum and minimum values of the sector waveform amplitude received by the 2ft eight-sector waveform receiving source meet the set threshold value is judged. The application solves the problem that the inconsistent amplitudes of sector first wave signals affect the accurate evaluation of cementing quality during the logging process of the sector cementing logging instrument, and ensures that the sector logging engineering information which can truly reflect the cementing quality is obtained.

Description

Technical Field

[0001] This invention belongs to the field of geophysical engineering logging and relates to a calibration method and device for sector cement bonded logging tools based on theoretical research. Background Technology

[0002] The quality of oil well cementing is crucial for the full utilization of oil wells, while cementing quality evaluation is key to the correct use of oil wells and the implementation of protective measures. Cement bond logging technology, represented by CBL / VDL, has been a fundamental method and means for detecting and evaluating cementing quality for many years, playing a vital role in the production of casing well cement bond quality testing. However, some situations still exist that cannot be well evaluated and interpreted, affecting oilfield production. In addition to standard 3-foot acoustic amplitude and 5-foot full-wavelength variable density displays, sector cement bond logging tools record the acoustic amplitude of eight sectors at a 2-foot source distance. Each probe has a 45-degree detection range. Based on the acoustic amplitude of the eight sectors, a cross-sectional diagram of the cement distribution outside the casing can be created, providing a visual image of the cement bond condition outside the casing. This allows for the identification of radial and longitudinal local deficiencies, voids, and cement inhomogeneity in the cement sheath, better meeting the needs of cementing quality evaluation. Currently, when the sector logging instrument is calibrated, it is placed at an angle into the calibrator, which can easily cause instrument eccentricity. This results in large amplitude differences in the first wave signals of the eight channels in the free casing section, poor consistency of sector signals, and affects the evaluation of logging results. Summary of the Invention

[0003] The purpose of this invention is to solve the problem in the prior art that when sector logging instruments are calibrated, the instrument is tilted when placed in the calibrator, which easily causes instrument eccentricity, large amplitude differences in the first wave signals of the eight channels in the free casing section, poor consistency of sector signals, and affects the evaluation of logging results. The invention provides a sector cement bonded logging instrument calibration method and device based on theoretical research.

[0004] To achieve the above objectives, the present invention employs the following technical solution:

[0005] The calibration method for sector cement bonded logging tools based on theoretical research includes:

[0006] Step 1: Rotate the scale instrument clockwise by the same angle in sequence until the scale instrument has rotated one full circle;

[0007] Step 2: Acquire the waveform amplitude curve received by the 2ft eight-sector waveform receiver after each rotation;

[0008] Step 3: Based on the waveform amplitude curves received by the 2ft eight-sector waveform receiver from several acquisitions, record the maximum and minimum values ​​of the waveform amplitude curves received by the 2ft eight-sector waveform receiver.

[0009] Step 4: Determine whether the difference between the maximum and minimum values ​​of the waveform amplitude curve of the 2ft eight-sector waveform receiver is less than the set threshold. If yes, the calibration is complete. If not, adjust the position of the calibration instrument on the calibration device and repeat steps 1 to 3 until the requirements are met.

[0010] A further improvement of the present invention is that:

[0011] Furthermore, each time a rotation is performed, each sector of the 2ft eight-sector waveform receiver receives a waveform amplitude curve.

[0012] Furthermore, the average value of the waveform curves received by the 2ft eight-sector waveform receiver is as follows: each sector of the 2ft eight-sector waveform receiver receives a waveform curve, and the waveform curve of each sector is the average value of the waveform curves received by its respective sector, which together constitute the average value of the waveform curves received by the 2ft eight-sector waveform receiver.

[0013] Furthermore, the sector cement bond logging tool calibration method based on theoretical research is realized through a sector cement bond logging tool calibration device; the sector cement bond logging tool calibration device includes: a calibration device, a pressurized water pump, a calibration instrument, an angle adjustment device, and a sealing ring;

[0014] An angle adjustment device is located at the lower end of the scale device to adjust the tilt of the scale device; the scale instrument is fitted inside the scale device, and a stabilizer is provided inside the scale device; the scale instrument passes through the stabilizer to keep the scale instrument in the center of the scale device.

[0015] A pressurized water pump is connected to the calibration device to supply water and pressurize it; a sealing ring is located between the calibration device and the calibration instrument to ensure the airtightness of the calibration device.

[0016] Furthermore, the stabilizers are positioned near the opening and tail of the scale device, respectively.

[0017] Furthermore, a pressurized water pump supplies water to the graduated device via a hose and a valve, the valve being located at the open end of the graduated device.

[0018] Furthermore, the calibration instrument includes a waveform transmitter, a 3ft waveform receiver, and a 5ft waveform receiver. The waveform transmitter is a monopole transmitter, and an eight-sector waveform receiver is set at a distance of 2ft from the waveform transmitter. The waveform transmitter is located at one end of the calibration instrument, and the 3ft waveform receiver, the 5ft waveform receiver, and the 2ft eight-sector waveform receiver receive the waveform transmitted by the waveform transmitter.

[0019] Furthermore, the booster pump is a manual pressure pump.

[0020] Furthermore, rotate the scale instrument clockwise by the same angle sequentially until the scale instrument has rotated one full circle, specifically as follows:

[0021] Step 9.1: Place the graduated instrument in the stabilizer of the graduated device, cover it with the sealing ring, then open the valve and pressurize the water pump to fill the graduated device with water until the entire graduated device is filled, then stop the water pump.

[0022] Step 9.2: Rotate the scale instrument 90 degrees and record the waveform amplitude curve received by the 2ft eight-sector waveform receiver from the waveform transmitter after each rotation;

[0023] Step 9.3: Repeat step 9.2, rotating the scale instrument 90 degrees clockwise until it returns to its original position;

[0024] Step 9.4: Rotate the scale instrument 45 degrees and record the waveform amplitude curve received by the 2ft eight-sector waveform receiver from the waveform transmitter.

[0025] Step 9.5: Repeat step 9.2, rotating the scale instrument 90 degrees clockwise until it returns to the position in step 9.4; obtain the maximum and minimum values ​​of the waveform amplitude curve received by the 2ft eight-sector waveform receiver.

[0026] Furthermore, a pressurized water pump fills the graduated device with water, reaching a pressure of 500 psi when the device is full.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] This invention collects waveform curves received by a 3ft waveform receiver, a 5ft waveform receiver, and a 2ft eight-sector waveform receiver on a calibration instrument. After the calibration instrument rotates one revolution, the waveform curves received by each receiver are superimposed and the average value is calculated to determine whether the average value of the waveforms from each receiver meets the set threshold. This invention solves the problem of inconsistent amplitude of the first wave signal in the sector cement bonding logging tool affecting the accurate evaluation of cementing quality during the logging process, ensuring the acquisition of sector logging engineering information that truly reflects the cementing quality.

[0029] Furthermore, by placing the calibration instrument within the calibration device and having it pass through the calibrator, the present invention keeps the calibration instrument in the exact center of the calibration device, thus solving the problem of varying degrees of eccentricity of the calibration instrument within the calibration device and improving the accuracy of the measurement. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a structural diagram of the calibration device for the sector cement bond logging tool based on theoretical research of the present invention;

[0032] Figure 2 This is a flowchart illustrating the usage method of the sector cement bond logging tool calibration device based on theoretical research of the present invention.

[0033] Figure 3 The following are examples of the effects of using conventional methods in the field.

[0034] Figure 4 The waveform of the 2ft eight-sector receiver is shown when the instrument's eccentricity is 5mm.

[0035] Figure 5 The waveform of the 2ft eight-sector receiver is shown when the instrument's eccentricity is 10mm.

[0036] Figure 6 The graph shows the variation of the amplitude of the first wave of the casing wave with the eccentricity.

[0037] Figure 7 The graph shows the change in eccentricity as the first wave of the casing wave arrives.

[0038] Figure 8 This is a diagram showing the indoor experimental results of the calibration method of this invention;

[0039] Figure 9 This is a diagram illustrating the effect of a field application example of the calibration method of the present invention.

[0040] Among them, 1-scale device; 2-scale instrument; 3-angle adjustment device; 4-valve; 5-centering device; 6-pressurized water pump; 7-sealing ring. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0042] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0043] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0044] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0045] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0046] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0047] The present invention will now be described in further detail with reference to the accompanying drawings:

[0048] See Figure 1 This invention discloses a sector cement bond logging tool calibration device based on theoretical research, comprising: calibration device 1, pressurized water pump 6, calibration instrument 2, angle adjustment device 3 and sealing ring 7;

[0049] Angle adjustment device 3 is located at the lower end of scale device 1 to adjust the tilt of scale device 1; scale instrument 2 is fitted inside scale device 1, and a stabilizer 5 is installed inside scale device 1; scale instrument 2 passes through stabilizer 5 to keep scale instrument 2 in the center of scale device 1; pressurized water pump 6 is connected to scale device 1 to supply water and pressurize scale device 1; sealing ring 7 is located between scale device 1 and scale instrument 2 to ensure the airtightness of scale device 1.

[0050] The stabilizers 5 are respectively positioned near the opening and tail of the scale device 1. The pressurized water pump 6 supplies water to the scale device via a hose and valve 4, with valve 4 located at the opening end of the scale device 1. The scale instrument 2 includes a waveform transmitter, a 3ft waveform receiver, and a 5ft waveform receiver. The waveform transmitter is a monopole transmitter, and an eight-sector waveform receiver is positioned 2ft away from the transmitter. The waveform transmitter is located at one end of the scale instrument, and the 3ft, 5ft, and 2ft eight-sector waveform receivers receive the waveforms transmitted by the transmitter. The pressurized water pump 6 is a manual pressure pump.

[0051] See Figure 2 This invention discloses a calibration method for sector cement-bonded logging tools based on theoretical research, comprising:

[0052] S101: Rotate the scale instrument 2 clockwise by the same angle until the scale instrument 2 has rotated one full circle.

[0053] S102: Acquire the waveform amplitude curve received by the 2ft eight-sector waveform receiver after each rotation; each rotation, each sector of the 2ft eight-sector waveform receiver receives a waveform amplitude curve.

[0054] S103: Based on the waveform amplitude curves received by the 2ft eight-sector waveform receiver from several acquisitions, obtain the maximum and minimum values ​​of the waveform amplitude curves received by the 2ft eight-sector waveform receiver.

[0055] Each sector in the 2ft eight-sector waveform receiver receives a waveform amplitude curve. The waveform curve of each sector is the average value of the waveform curves received by its respective sector, which together constitute the average value of the waveform curves received by the 2ft eight-sector waveform receiver.

[0056] S104: Determine whether the difference between the maximum and minimum values ​​of the waveform curves received by each of the 2ft eight-sector waveform receivers is less than the set threshold. If yes, the calibration is complete. If no, adjust the position of the calibration instrument on the calibration device and repeat steps S101 to S103 until the requirements are met.

[0057] Rotate the scale instrument clockwise by the same angle sequentially until the scale instrument has rotated one full circle, specifically:

[0058] Step 1: Place the calibrator 2 in the stabilizer 5 of the calibrator device 1, cover it with the sealing ring 7, then open the valve 4, and the pressurized water pump 6 injects water into the calibrator device 1 until the entire calibrator device 1 is filled. Then the pressurized water pump 6 stops supplying water. The water pressure when the pressurized water pump 6 injects water into the calibrator device 1 and fills the entire calibrator device is 500 psi.

[0059] Step 2: Rotate the scale instrument 2 by 90 degrees and record the waveform amplitude curve received by the waveform transmitter from the waveform transmitter after each rotation;

[0060] Step 3: Repeat step 2, rotating the scale instrument 2 90 degrees clockwise until it returns to its original position;

[0061] Step 4: Rotate the scale instrument 2 by 45 degrees and record the waveform curve received by the 2ft eight-sector waveform receiver from the waveform transmitter.

[0062] Step 5: Repeat step 2, rotating the scale instrument 2 90 degrees clockwise until it returns to the position in step 7.4; obtain the maximum and minimum values ​​of the waveform amplitude received by the 2ft eight-sector waveform receiver.

[0063] Conventional calibration methods for sector cement bond logging tools, including

[0064] a) Tilt the graduated cylinder at a 30° angle.

[0065] b) Place the instrument probe into the graduated cylinder, fill it with water, and tighten the connecting cap.

[0066] c) Use a hand pump to pump clean water into the graduated cylinder. When pressure is applied, slowly open the vent valve to release the gas. Repeat this step until no more air bubbles are released.

[0067] d) After closing the vent valve, continue pumping clean water until the pressure inside the graduated cylinder reaches 3.5 MPa.

[0068] e) Connect the instrument to the test system using a flexible cable.

[0069] f) Start the test system, power the downhole instrument, and calibrate the downhole instrument. Refer to Table 1 for the nominal values ​​of the instrument calibration data.

[0070] g) After completing the calibration, vent and depressurize the calibration cylinder, then remove the instrument from the calibration cylinder.

[0071] h) The nominal values ​​of the instrument scale are shown in Table 1.

[0072] Table 1 Instrument Scale Data Table Nominal Values

[0073] 2.5±0.5％ CBL raw values 2.5±0.5％ VDL raw values 2±0.5％ Sector raw value average CBL scale value (72mV) Sector scale value (100mV)

[0074] The above devices and methods are often used for indoor calibration of sector instruments. However, this method has a problem: the instrument has varying degrees of eccentricity in the calibration cylinder, which causes differences in the first wave amplitude of the instrument sector and affects the accurate evaluation of cementing quality.

[0075] Figure 3 The first column shows the maximum, minimum, and average curves of the signal amplitude of the 8 sectors. Due to imperfections in the calibration method, the amplitude of the first wave in the sector varies greatly in the free casing section, resulting in curve separation.

[0076] Based on the wellbore wave theory, this paper analyzes the influence of sector cement cement logging tool eccentricity on casing wave amplitude through numerical simulation and waveform comparison. It finds the influence law of instrument eccentricity on sector signal amplitude and proposes an indoor calibration method for sector cement cement logging tools based on theoretical numerical simulation. This method achieves accurate indoor calibration and standardization of sector logging tools, thereby improving the accuracy evaluation of cement cementing quality sector logging.

[0077] Analysis of the influence of different eccentric distances on the indoor calibration of cement-bonded logging instruments in sectors, including:

[0078] Step 1: Numerical simulation of the influence of different eccentric distances on the magnitude and arrival time of the first wave in the sector, such as... Figure 4 and Figure 5 As shown.

[0079] Step 2: Analyze the relationship between the eccentricity distance and the magnitude of the first wave amplitude in the sector based on the numerical simulation results.

[0080] Step 3: Based on the results of Steps 1 and 2, plot the receiver amplitude at different source distances in the free sleeve. Figure 6 ) and at that time ( Figure 7 The curve showing the change in instrument eccentricity.

[0081] Step 4: Summarize the above calculation and analysis results.

[0082] Numerical simulation results

[0083] Figure 4 and Figure 5 The waveforms received by the instrument at 2ft circumferentially in an eight-sector configuration are presented under different instrument eccentricity distances in a free casing well with the instrument centered. Figure 4 The instrument eccentricity distance (dr in the figure) is 5mm. Figure 5The instrument eccentricity distance (dr in the figure) is 10 mm. Since the entire structure is planar symmetrical when the acoustic system is eccentric in a free-casing well, only the waveforms of receivers in sectors 1-5 are shown; receivers 6, 7, and 8 are symmetrical to receivers 4, 3, and 2, respectively. The open-hole radius is 100 mm, and the inner and outer radii of the casing are 62 mm and 70 mm, respectively.

[0084] As the eccentricity increases, the arrival time and amplitude of the first wave (first positive peak) from the casing become distorted, with significant differences observed in each receiver's arrival time. When the instrument is eccentric towards receiver 1, receiver 5 exhibits a much larger amplitude and a shorter arrival time compared to receiver 1. The later arrival time of receiver 5's first wave is due to its greater distance from the casing's inner wall, requiring the casing wave to travel an additional distance in the fluid. The larger amplitude of receiver 5's first wave is due to its closer proximity to the casing's center. As the eccentricity increases, the difference in arrival times between receivers 1 and 5 also increases. Subsequent casing wave arrivals are also affected by the eccentricity, but without a clear pattern, and their amplitude is not significantly affected.

[0085] Free casing well simulation waveform amplitude and arrival time analysis

[0086] The simulated waveform was processed and analyzed to extract the arrival time and amplitude of the casing wave. Based on actual field conditions, the casing wave amplitude was defined as the amplitude of the first positive peak, and the arrival time as the arrival time of the first positive peak. The extraction method was as follows: considering the variation in arrival time caused by eccentricity, a fixed time window of period (50μs) was selected, and the amplitude and arrival time of the first positive peak within this time window were read. Figure 6 , Figure 7 It is the normalized average acoustic amplitude of the instrument at different source distances in the free sleeve. Figure 6 ) and at that time ( Figure 7 The curves show the variation of instrument eccentricity with the distance between the source and receiver. The horizontal axis represents the instrument eccentricity (Eccentricity), in mm. The three curves correspond to the receivers at source distances of 2ft, 3ft, and 5ft, respectively.

[0087] Figure 6 and Figure 7 This indicates that the average waveform at 2ft is a composite waveform obtained by directly adding the waveforms of the eight sector receivers, while the average sound pressure waveform is directly recorded by the 3ft and 5ft receivers. It can be seen that as the eccentricity increases, the sound amplitude of each receiver gradually decreases, with a linear relationship at 3ft and 5ft, and a slower decrease at 2ft. When the instrument is eccentric, the changes in sound pressure at each receiver are very small.

[0088] Based on the above theoretical calculations and analysis, the following conclusions can be drawn: even a small eccentricity has a significant impact on the amplitude of the sector. Therefore, the influence of eccentricity must be eliminated during sector instrument calibration and measurement to ensure the accuracy of the instrument's sector amplitude. During the calibration process of the original calibration device, the influence of eccentricity on the amplitude of the eight sectors is different at different positions. The single-point calibration method cannot guarantee the consistency of the amplitude calibration of the eight sectors.

[0089] Based on the above calculations and analysis, this invention proposes an 8-point rotational calibration method to ensure the consistency of the amplitude of the first wave in the sector, and proposes an indoor calibration method for sector cement-bonded logging instruments based on theoretical research.

[0090] Combination Figure 1 The scale device and Figure 9 The field logging curves further illustrate the present invention:

[0091] Step 1: Place the graduated instrument 2 in the stabilizer 5 of the graduated device 1, cover it with the sealing ring 7, then open the valve 4, and the pressurized water pump 6 fills the graduated device 1 with water until the entire graduated device 1 is filled. Then the pressurized water pump 6 stops supplying water. The water pressure when the pressurized water pump 6 fills the graduated device 1 with water is 500 psi.

[0092] Step 2: Set the voltage of the 3-foot and 5-foot waveform receivers to 2.5V and ensure correct timing; the timing of the 5.5-inch bushing is 236µs. Set the voltage of all sectors of the 2ft eight-sector waveform receiver to 2.0V.

[0093] Step 3: Rotate the scale instrument 2 by 90 degrees and record the voltage of the 2ft eight-sector waveform receiver after each rotation;

[0094] Step 4: Repeat step 3, rotating the scale instrument 2 90 degrees clockwise until it returns to its original position;

[0095] Step 5: Rotate the scale instrument 2 by 45 degrees and record the voltage magnitude of the 2ft eight-sector waveform receiver;

[0096] Step 6: Repeat step 3, rotating the scale instrument 2 90 degrees clockwise until it returns to the position in step 7.4; obtain the maximum and minimum voltage values ​​of the 2ft eight-sector waveform receiver.

[0097] The difference between the maximum and minimum values ​​between sectors should not exceed 0.20V. If it exceeds 0.20V, this step should be repeated from different locations. If there is no improvement, the instrument may require repair. By following these steps, the instrument calibration is complete.

[0098] The change in the waveform curve is represented by the change in the amplitude of the signal voltage.

[0099] Figure 9 This is a field application example of an instrument calibrated using the calibration method of this invention. The first column of the graph shows the sector amplitude curves measured by the instrument in the free casing section of the well. The amplitude of the first wave in each sector is consistent, and the curves basically overlap. This indicates that the calibration method is correct and the logging curves are accurate and reliable.

[0100] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A calibration method for sector cement-bonded logging tools based on theoretical research, characterized in that, include: Step 1: Rotate the scale instrument clockwise by the same angle in sequence until the scale instrument has rotated one full circle; Step 2: Acquire the waveform amplitude curve received by the 2ft eight-sector waveform receiver after each rotation; Step 3: Based on the waveform amplitude curves received by the 2ft eight-sector waveform receiver from several acquisitions, record the maximum and minimum values ​​of the waveform amplitude curves received by the 2ft eight-sector waveform receiver. Step 4: Determine whether the difference between the maximum and minimum values ​​of the waveform amplitude curve of the 2ft eight-sector waveform receiver is less than the set threshold. The difference between the maximum and minimum values ​​is the difference between the maximum and minimum voltage values ​​between sectors. If yes, the calibration is complete. If no, adjust the position of the calibration instrument on the calibration device and repeat steps 1 to 3 until the requirements are met. The theoretical research includes: Based on wellbore wave theory, the influence of sector cement bond logging tool eccentricity on casing wave amplitude is analyzed through numerical simulation and waveform comparison. The influence law of tool eccentricity on sector signal amplitude is found, specifically: S1. Numerical simulation of the influence of different eccentric distances on the magnitude and arrival time of the first wave in the sector; S2. Analyze the relationship between the eccentricity distance and the magnitude of the first wave amplitude in the sector based on the numerical simulation results; S3. Based on the results of steps S1 and S2, draw the curves showing the changes in receiver amplitude and arrival time with the instrument eccentricity distance at different source distances in the free sleeve. S4. Based on the above calculations and analysis, the conclusion is that even a small eccentricity has a significant impact on the amplitude of the sector. Therefore, the influence of eccentricity must be eliminated when calibrating the sector instrument to ensure the accuracy of the instrument's sector amplitude. When the instrument is eccentric, the changes in arrival times of each receiver are very small.

2. The calibration method for sector cement-bonded logging tools based on theoretical research according to claim 1, characterized in that, Each time the rotation occurs, each sector of the 2ft eight-sector waveform receiver receives a waveform amplitude curve.

3. The calibration method for sector cement-bonded logging tools based on theoretical research according to claim 1, characterized in that, The theoretical research-based sector cement bond logging tool calibration method is implemented through a sector cement bond logging tool calibration device; the sector cement bond logging tool calibration device includes: a calibration device (1), a pressurized water pump (6), a calibration instrument (2), an angle adjustment device (3), and a sealing ring (7). The angle adjustment device (3) is located at the lower end of the scale device (1) to adjust the tilt of the scale device (1); the scale instrument (2) is fitted inside the scale device (1), and a stabilizer (5) is provided inside the scale device (1); the scale instrument (2) passes through the stabilizer (5) to keep the scale instrument (2) in the center of the scale device (1); The pressurized water pump (6) is connected to the scale device (1) to supply water and pressurize the scale device (1); the sealing ring (7) is located between the scale device (1) and the scale instrument (2) to ensure the airtightness of the scale device (1).

4. The sector cement bond logging tool calibration method based on theoretical research according to claim 3, characterized in that, The straightener (5) is positioned near the opening and tail of the scale device (1).

5. The sector cement bond logging tool calibration method based on theoretical research according to claim 4, characterized in that, The pressurized water pump (6) supplies water and pressurizes the scale device through a hose and a valve (4), with the valve (4) located at the open end of the scale device (1).

6. The calibration method for sector cement-bonded logging tools based on theoretical research according to claim 5, characterized in that, The calibration instrument (2) includes a waveform transmitter, a 3ft waveform receiver and a 5ft waveform receiver. The waveform transmitter is a monopole transmitter and an eight-sector waveform receiver is set at a distance of 2ft from the waveform transmitter. The waveform transmitter is located at one end of the calibration instrument. The 3ft waveform receiver, the 5ft waveform receiver and the 2ft eight-sector waveform receiver receive the waveforms sent by the waveform transmitter.

7. The calibration method for sector cement-bonded logging tools based on theoretical research according to claim 6, characterized in that, The pressurized water pump (6) is a manual pressure pump.

8. The calibration method for sector cement-bonded logging tools based on theoretical research according to claim 7, characterized in that, The process of rotating the scale instrument clockwise by the same angle sequentially until the scale instrument has rotated one full circle is specifically as follows: Step 9.1: Place the calibration instrument (2) in the stabilizer (5) of the calibration device (1), cover it with the sealing ring (7), then open the valve (4), and the pressurized water pump (6) fills the calibration device (1) with water until the entire calibration device (1) is filled, and then the pressurized water pump (6) stops supplying water; Step 9.2: Rotate the calibration instrument (2) by 90 degrees and record the waveform amplitude curve received by the 2ft eight-sector waveform receiver from the waveform transmitter after each rotation; Step 9.3: Repeat step 9.2, rotating the scale instrument (2) 90 degrees clockwise until it returns to its original position; Step 9.4: Rotate the calibration instrument (2) by 45 degrees and record the waveform amplitude curve of the waveform transmitter received by the 2ft eight-sector waveform receiver; Step 9.5: Repeat step 9.2, and rotate the scale instrument (2) 90 degrees clockwise until it returns to the position of step 9.4; obtain the maximum and minimum values ​​of the waveform amplitude curve received by the 2ft eight-sector waveform receiver.

9. The sector cement bond logging tool calibration method based on theoretical research according to claim 8, characterized in that, The pressurized water pump (6) fills the scale device (1) with water, and the water pressure when the entire scale device is filled is 500 psi.

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