A method and system for sonic logging of a cased well

Abstract

This invention relates to the field of acoustic logging technology, specifically disclosing an acoustic logging method and system for cased wells. The method includes: acquiring the position signal of an acoustic transmitter within the cased well and the reflected acoustic signal; determining whether the reflected acoustic signal includes formation wave signals that are not distorted by the well media; converting the undesirable wave signal into a first electrical control signal, calculating the position of the undesirable wave signal based on the acoustic transmitter position signal and the reflected acoustic signal, and controlling the acoustic transmitter to rotate closer to the undesirable wave signal position until a good wave signal is generated; or converting the good wave signal into a second electrical control signal, controlling the acoustic transmitter to rotate back to its original position based on the acoustic transmitter position signal, and continuing logging until the undesirable wave signal is acquired again, repeating the above control steps. This method can autonomously adjust the position of the acoustic transmitter even when the signal data is interfered with, improving the accuracy of detection.

Description

Technical Field

[0001] This invention relates to the field of acoustic logging technology, specifically to an acoustic logging method and system for casing wells. Background Technology

[0002] Sonic logging involves placing a controlled acoustic source into the well. The sound waves emitted by the source cause vibrations in surrounding particles, generating body waves (P-waves and S-waves) in the formation and induced interface waves (pseudo-Rayleigh waves and Stoneley waves) at the wellbore-drilling fluid interface. These waves, acting as carriers of formation information, are received by a downhole receiver and transmitted to the surface for recording. An acoustic logging tool is a device that performs these functions, comprising a transmitting circuit, a sound source device, a receiving array, and receiving circuitry. Acoustic logging tools used in cased wells primarily rely on the acoustic amplitude information in the logging data to study cementing quality and observe information such as rock wall conditions, fractures, and casing damage. Given the increasing complexity and miniaturization of oil and gas reservoirs in terms of morphology and scale, research into related acoustic logging tools is urgently needed.

[0003] Existing acoustic transducer transmitters and receivers are fixed on the outside of the acoustic logging tool. The immovable nature of the ultrasonic transmitter head increases the requirements for the position of the logging tool. This often leads to problems where the received signal data is greatly affected by direct waves and mud in the well due to poor positioning of the logging tool, which in turn increases the difficulty of processing the received acoustic signal and limits its accuracy. Summary of the Invention

[0004] The purpose of this invention is to provide a sonic logging method for casing wells, which can autonomously adjust the position of the sonic transmitter when the signal data is interfered with, thereby improving the accuracy of detection.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A sonic logging method for casing wells includes:

[0007] Acquire the position signal of the acoustic wave transmitter inside the casing well and the reflected acoustic wave signal;

[0008] Determine whether the reflected acoustic signal includes formation wave signals that are not distorted by the well medium;

[0009] If the reflected acoustic signal does not include the formation wave signal that is not distorted by the medium inside the well, it is judged as a bad wave signal; if the reflected acoustic signal includes the formation wave signal that is not distorted by the medium inside the well, it is judged as a good wave signal.

[0010] The process involves converting the undesirable wave signal into a first electrical control signal, calculating the position of the undesirable wave signal based on the position signal of the acoustic wave transmitter and the reflected acoustic wave signal, and controlling the acoustic wave transmitter to rotate closer to the undesirable wave signal position until a good wave signal is generated; or converting the good wave signal into a second electrical control signal, controlling the acoustic wave transmitter to rotate back to its original position based on the position signal of the acoustic wave transmitter, and continuing logging until the undesirable wave signal is collected again, at which point the above control steps are repeated.

[0011] In a further embodiment, the defective wave signal includes a non-stratum wave signal or a stratum wave distortion signal.

[0012] In a further embodiment, the acquisition of the position signal of the acoustic wave transmitter inside the casing well and the reflected acoustic wave signal includes:

[0013] Sound waves are emitted horizontally by a sound wave transmitter, and the sound waves reflected by the well medium and the formation in the well section are received by a sound wave receiver. The emission position is determined by a positioner.

[0014] In a further embodiment, the method of converting the defective wave signal into a first electrical control signal, calculating the position of the defective wave signal based on the position signal of the acoustic wave transmitter and the reflected acoustic wave signal, and controlling the acoustic wave transmitter to rotate closer to the position of the defective wave signal includes:

[0015] When the reflected sound wave is determined to be a defective signal, the position of the defective signal relative to the sound wave transmitter is calculated based on the position signal of the sound wave transmitter and the reflected sound wave signal. The defective signal is then converted into a first electrical control signal and sent to the rotating motor and the telescopic cylinder. The rotating motor is controlled to rotate and the telescopic cylinder is controlled to extend, thereby moving the sound wave transmitter closer to the position of the defective signal.

[0016] In a further embodiment, the method of converting the acoustic wave signal into a second electrical control signal and controlling the acoustic wave transmitter to rotate back to its original position based on the position signal of the acoustic wave transmitter includes:

[0017] When the reflected sound wave is determined to be a good wave signal, the good wave signal is converted into a second electrical control signal and sent to the rotating motor and the telescopic cylinder to control the rotating motor and the telescopic cylinder to return to their original positions. Then, based on the position signal of the sound wave transmitter, it is determined whether the position of the sound wave transmitter has returned to its original position.

[0018] Based on the same concept, this invention proposes a sonic logging system for casing wells, used to perform any of the sonic logging methods for casing wells described above, comprising:

[0019] The acquisition module is used to acquire the position signal of the acoustic wave transmitter inside the casing well and the reflected acoustic wave signal;

[0020] The judgment module is used to determine whether the reflected acoustic signal includes formation wave signals that are not distorted by the well medium; if the reflected acoustic signal does not include formation wave signals that are not distorted by the well medium, it is judged as a bad wave signal; if the reflected acoustic signal includes formation wave signals that are not distorted by the well medium, it is judged as a good wave signal.

[0021] The conversion module is used to convert the undesirable wave signal into a first electrical control signal, calculate the position of the undesirable wave signal based on the position signal of the acoustic wave transmitter and the reflected acoustic wave signal, and control the acoustic wave transmitter to rotate closer to the position of the undesirable wave signal until a good wave signal is generated; or convert the good wave signal into a second electrical control signal, control the acoustic wave transmitter to rotate back to its original position based on the position signal of the acoustic wave transmitter, and continue logging until the undesirable wave signal is collected again, at which point the above control steps are repeated.

[0022] In a further embodiment, the acquisition module includes a sound wave transmitter and receiver, a connecting rod, a rotary motor, a telescopic cylinder, a position sensor, and a signal transmission line. The sound wave transmitter and receiver is fitted onto one end of the position sensor, the other end of the position sensor is connected to one end of the connecting rod, the other end of the connecting rod is connected to the piston end of the telescopic cylinder, the cylinder seat end of the telescopic cylinder is connected to the shaft end of the rotary motor, and the housing end of the rotary motor is connected to the drill pipe of the casing well. Both the sound wave transmitter and receiver and the position sensor are connected to the judgment module via the signal transmission line, which is used to send the reflected sound wave signal acquired by the sound wave transmitter and receiver and the position signal measured by the position sensor to the judgment module.

[0023] In a further embodiment, the acoustic wave transmitter and receiver includes an acoustic wave transmitter head, a helical spring, and a spring fixing seat. The acoustic wave transmitter head is slidably connected to the end of the connecting rod away from the telescopic cylinder. The spring fixing seat is connected to the middle of the connecting rod. The helical spring is connected between the acoustic wave transmitter head and the spring fixing seat.

[0024] In a further embodiment, an anti-collision sensor is installed between the acoustic wave transmitter and the positioner.

[0025] In a further embodiment, the positioner is a GPS wireless positioner.

[0026] The beneficial effects of this invention are:

[0027] This invention dynamically adjusts the position of the acoustic wave transmitter by collecting the position signal of the acoustic wave transmitter and the reflected acoustic wave signal. This effectively avoids the influence of some interfering media, emits excellent waveforms, and can change the logging strategy according to the reflection wave effect. It obtains data while filtering out interference waves such as interference reflection waves from mud in the well, so as to achieve clearer and faster logging. This acoustic logging method and system for cased wells can change the transmission position and the transmission direction of the direct wave when the observation point position remains unchanged. This greatly reduces the influence of the direct wave on the received signal wave, thereby reducing the difficulty of processing the received acoustic wave signal data and improving the accuracy of logging results. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a block diagram illustrating the principle of an acoustic logging method for a casing well according to an embodiment of the present invention.

[0030] Figure 2 This is a schematic diagram of the connection of the acquisition module in an acoustic logging system for a casing well according to an embodiment of the present invention.

[0031] In the diagram: 1. Acoustic wave transmitter and receiver; 101. Acoustic wave transmitter head; 1011. Material layer; 1012. Connector; 1013. Piezoelectric device; 1014. Metal sleeve; 1015. Sound-absorbing pad; 102. Helical spring; 103. Spring fixing seat; 2. Connecting rod; 3. Rotary motor; 4. Telescopic cylinder; 5. Positioner. Detailed Implementation

[0032] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] like Figure 1 As shown, a sonic logging method for a cased well includes the following steps:

[0034] Step S1: Acquire the position signal of the acoustic wave transmitter 101 inside the casing well and the reflected acoustic wave signal through the acquisition module;

[0035] Step S2: Determine whether the reflected acoustic signal includes formation wave signals that are not distorted by the well medium through the judgment module;

[0036] If the reflected acoustic signal does not include formation wave signals that are not distorted by the well medium, it is judged as a bad signal; if the reflected acoustic signal includes formation wave signals that are not distorted by the well medium, it is judged as a good signal.

[0037] Step S3: The conversion module converts the undesirable wave signal into a first electrical control signal, calculates the position of the undesirable wave signal based on the position signal of the acoustic wave transmitter 101 and the reflected acoustic wave signal, and controls the acoustic wave transmitter 101 to rotate closer to the position of the undesirable wave signal until a good wave signal is generated; or the good wave signal is converted into a second electrical control signal, and the acoustic wave transmitter is controlled to rotate back to its original position based on the position signal of the acoustic wave transmitter, and logging continues until the undesirable wave signal is collected again, at which point the above control steps are repeated.

[0038] The specific implementation method can be as follows: First, the acquisition module is assembled on the ground and forms an acoustic logging system with the acoustic wave tester receiver, computer, and other components. The acquisition module is lowered into the test well section along with the drill pipe. The positioner 5 can test the position of the acoustic wave transmitter 101. An electrical signal is input on the ground to excite the acoustic wave transmitter 101 to emit acoustic waves. The acoustic waves propagate to the casing, cement stone, mud, and formation, and are reflected in the corresponding medium and finally received by the acoustic wave receiver. The acoustic wave receiver can be integrated with the acoustic wave transmitter 101 or connected to other locations on the acquisition module that can effectively receive reflected waves. When it receives the reflected waves, The data is transmitted to a ground computer for defective wave identification. If the test can effectively identify the cement stone bonding quality and formation information of the test section, it is considered a good wave, and other sections are tested. If the test results in a defective wave, the computer is notified to mark the location of the defective wave. The acoustic wave transmitter 101 is then rotated to move closer to the location of the defective wave signal until a good wave signal is generated. The position of the acoustic wave transmitter 101 is recorded by the position sensor 5 and fed back to the computer. The computer calculates the direction and location of the measured data based on the position of the acoustic wave transmitter 101, such as the direction and location of formation defects, making the well logging data more complete and clear, which is convenient for the next drilling research.

[0039] Based on the principles of the above method, some implementation methods or structures are provided. Adverse wave signals include signals without formation waves or distorted formation waves. When analyzing acoustic wave types, distorted signals also include formation wave signals that cannot be resolved. This method allows for faster and more comprehensive identification of adverse wave signals, without needing to consider the influence of reflected wave signals from intermediate waves such as well casing and wellbore rocks. This is because, generally, if formation wave signals are present, these reflected waves should also be present, and these reflected waves are of little significance for formation research, only for well condition research.

[0040] The acquisition of the position signal of the acoustic wave transmitter inside the casing well and the reflected acoustic wave signal includes:

[0041] Sound waves are emitted horizontally by the acoustic transmitter 101, and the acoustic receiver receives the sound waves reflected by the well medium and the formation in the well section. The emission position is determined by the position sensor 5. Compared with oblique emission of sound waves, this method makes it easier to calculate formation location information and analyze the wave propagation distance by lateral positioning.

[0042] A method for converting a defective wave signal into a first electrical control signal and controlling the acoustic wave transmitter head to rotate closer to the position of the defective wave signal includes:

[0043] When the reflected sound wave is determined to be an undesirable signal, the position of the undesirable signal relative to the sound wave transmitter is calculated based on the position signal of the sound wave transmitter and the reflected sound wave signal. The undesirable signal is then converted into a first electrical control signal and sent to the rotary motor 3 and the telescopic cylinder 4. The first electrical control signal controls the rotation of the rotary motor 3 and the extension of the telescopic cylinder 4 to move closer to the position of the undesirable signal. The rotary motor 3 facilitates the adjustment of the rotation of the sound wave transmitter 101, thereby enabling the emission of sound waves at different positions within the well. This avoids the sound wave transmitter 101 being affected by undesirable positions such as well mud or other interference waves. Similarly, the extension of the telescopic cylinder 4 allows the sound wave transmitter 101 to further pass through these affected areas, such as directly reaching wellbore defects, directly detecting relevant formation information, and determining the relevant well failure situation or further development value.

[0044] The method of converting the good wave signal into a second electrical control signal, and controlling the sound wave transmitter to rotate back to its original position based on the position signal of the sound wave transmitter:

[0045] When the reflected sound wave is a good signal, a second electrical control signal is sent to the rotary motor 3 and the telescopic cylinder 4 to control them to return to their original positions. Then, based on the position signal of the sound wave transmitter 101, it is determined whether the position of the sound wave transmitter 101 has returned to its original position. If the position signal of the sound wave transmitter 101 coincides with or is similar to that when it is not moving, it is determined that it has returned to its original position. This ensures that the sound wave transmitter 101 can be better positioned in the designed protection position when it continues to probe in the well along with the drill pipe, and also prevents the calculation from becoming too complex due to the introduction of too many positions.

[0046] Based on the above method principle, a sonic logging system for casing wells can be designed, including:

[0047] The acquisition module is used to acquire the position signal of the acoustic wave transmitter inside the casing well and the reflected acoustic wave signal;

[0048] The judgment module is used to determine whether the reflected acoustic signal includes formation wave signals that are not distorted by the well medium; if the reflected acoustic signal does not include formation wave signals that are not distorted by the well medium, it is judged as a bad wave signal; if the reflected acoustic signal includes formation wave signals that are not distorted by the well medium, it is judged as a good wave signal.

[0049] The conversion module is used to convert the undesirable wave signal into a first electrical control signal, calculate the position of the undesirable wave signal based on the position signal of the acoustic wave transmitter and the reflected acoustic wave signal, and control the acoustic wave transmitter to rotate closer to the position of the undesirable wave signal until a good wave signal is generated; or convert the good wave signal into a second electrical control signal, control the acoustic wave transmitter to rotate back to its original position based on the position signal of the acoustic wave transmitter, and continue logging until the undesirable wave signal is collected again, at which point the above control steps are repeated.

[0050] like Figure 2 As shown, the acquisition module structure may include a sound wave transmitter and receiver 1, a connecting rod 2, a rotary motor 3, a telescopic cylinder 4, a position sensor 5, and a signal transmission line. The sound wave transmitter and receiver 1 is fitted onto one end of the position sensor 5, the other end of the position sensor 5 is connected to one end of the connecting rod 2, the other end of the connecting rod 2 is connected to the piston end of the telescopic cylinder 4, the cylinder seat end of the telescopic cylinder 4 is connected to the shaft end of the rotary motor 3, and the housing end of the rotary motor 3 is connected to the drill pipe of the casing well. The sound wave transmitter and receiver 1 and the position sensor 5 are both connected to the judgment module through the signal transmission line, which is used to send the reflected sound wave signal acquired by the sound wave transmitter and receiver 1 and the position signal measured by the position sensor 5 to the judgment module. The judgment module uses the logic judgment circuit of an existing computer processor or a microcontroller. The conversion module uses an existing converter to convert the position signal and sound wave signal judged by the judgment module into control signals. The specific circuit connection method can be adjusted according to existing technology and requirements. In this way, the position of the acquisition module can be measured in real time by the position sensor 5 and the received reflected sound wave can be sent directly to the judgment module for faster data transmission and faster feedback on the execution of the relevant rotation or extension actions of the judgment and acquisition module 1.

[0051] The acoustic wave transmitter and receiver 1 includes an acoustic wave transmitter 101, a helical spring 102, and a spring fixing seat 103. The acoustic wave transmitter 101 is slidably connected to the end of the connecting rod 2 away from the telescopic cylinder 4. The spring fixing seat 103 is connected to the middle of the connecting rod 2. The helical spring 102 is connected between the acoustic wave transmitter 101 and the spring fixing seat 103. When the acoustic wave transmitter 101 comes into contact with a solid object, it will compress the helical spring 102 to prevent damage from contact. When the well wall is irregular with protrusions or depressions, its local imbalance will be transmitted to the helical spring 102 through the acoustic wave transmitter 101. The helical spring 102 will be subjected to further pressure if the well wall is protruding or under tension, or if the well wall is concave. This allows the entire structure to remain stable through fine adjustment of the helical spring 102, and ensures that the transmitter head can make close contact with the well wall.

[0052] An anti-collision sensor is installed between the acoustic wave transmitter 101 and the positioner 5. When the acoustic wave transmitter 101 comes into contact with a collision object, the spiral spring 102 is compressed to its full position, which triggers the anti-collision sensor to generate a signal, controlling the telescopic cylinder 4 to retract, preventing the acoustic wave transmitter 101 from being damaged due to excessive pressure, thus ensuring its safety during use.

[0053] Positioner 5 is a GPS wireless positioner. The GPS wireless positioner includes a wireless communication system and a positioning system. The positioning system mainly includes a GPS chip, which is used to detect the specific location of the acoustic transmitter 101 in real time; the wireless communication module is mainly used to send the positioning information back to the computer.

[0054] The acoustic transmitter 101 generally adopts an ultrasonic emission structure, including a material layer 1011, which is preferably disc-shaped. The material is a PVDT electric film ultrasonic emission material with a density of less than 80 kg / m3, an outer diameter of 60 mm, and a thickness of 5 mm. The material layer 1011 is mainly oriented towards the direction of acoustic logging or in contact with the measuring body.

[0055] The acoustic transmitter 101 also includes a frustum-shaped connector 1012, preferably made of aluminum, which can provide ultrasonic signals that emit vertical beams and 360-degree omnidirectional beams toward the material layer 1011.

[0056] The acoustic emitting head 101 also includes piezoelectric devices 1013, typically two to four in number, with an outer diameter preferably of 35 mm and a thickness of 7 mm. The piezoelectric devices 1013 are slidably connected to the connecting rod 2, allowing them to move freely relative to each other and contacting the connecting head 1012. The piezoelectric devices 1013 transmit voltage-controlled vibrational ultrasound to the connecting head 1012; that is, the piezoelectric devices 1013 convert electrical energy into mechanical energy vibration, and the resulting acoustic signal is transmitted to the connecting head 1012, thus achieving the ultrasonic emission function. The connecting head 1012, made of aluminum alloy, vibrates due to the minute mechanical deformation of the piezoelectric devices 1013. These vibrations propagate to the surrounding medium, generating sound waves. This process is a crucial step in converting electrical signals into mechanical energy through the piezoelectric effect and propagating them through the acoustic emitting head.

[0057] The acoustic wave transmitter 101 can also be connected to a metal sleeve 1014 and a sound-absorbing pad 1015. The sound-absorbing pad 1015 is made of porous foam plastic material, which is filled with tiny pores. When sound waves enter these pores, the energy of the sound waves is converted into heat energy, thereby achieving the effect of sound absorption. Furthermore, since longitudinal waves propagate through the compression and expansion of the medium, the porous structure of the porous material can effectively capture and absorb this type of wave, thus playing a role in absorbing the longitudinal wave train sound wave signal. The radial micro-gap between the metal sleeve 1014 and the rigid connecting rod 2 allows for axial relative movement between the two while preventing excessive oscillation of the metal sleeve 1014. Due to the strong acoustic wave transmission of the metal sleeve 1014, its high conductivity allows sound waves to be transmitted to the sound-absorbing pad 1015 to the maximum extent through the metal sleeve 1014, thereby filtering out noise from non-surface longitudinal waves and further preventing interference from unwanted longitudinal waves.

[0058] In addition, other components included in the acoustic wave transmitter and receiver 1, such as the acoustic wave receiver, are consistent with those in conventional logging tools.

[0059] It should be noted that the terms "first," "second," etc., used in this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein.

[0060] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, 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.

[0061] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A sonic logging method for casing wells, characterized in that, include: Acquire the position signal of the acoustic transmitter inside the casing well and the reflected acoustic signal; Determine whether the reflected acoustic signal includes formation wave signals that are not distorted by the well medium; If the reflected acoustic signal does not include the formation wave signal that is not distorted by the medium inside the well, it is judged as a bad wave signal; if the reflected acoustic signal includes the formation wave signal that is not distorted by the medium inside the well, it is judged as a good wave signal. The process involves converting the undesirable wave signal into a first electrical control signal, calculating the position of the undesirable wave signal based on the position signal of the acoustic wave transmitter and the reflected acoustic wave signal, and controlling the acoustic wave transmitter to rotate closer to the undesirable wave signal position until a good wave signal is generated; or converting the good wave signal into a second electrical control signal, controlling the acoustic wave transmitter to rotate back to its original position based on the position signal of the acoustic wave transmitter, and continuing logging until the undesirable wave signal is collected again, at which point the above control steps are repeated.

2. The acoustic logging method for a casing well according to claim 1, characterized in that, The undesirable wave signals include those without formation waves or those with distorted formation waves.

3. The acoustic logging method for a casing well according to claim 2, characterized in that, The acquisition of the position signal of the acoustic wave transmitter inside the casing well and the reflected acoustic wave signal includes: Sound waves are emitted horizontally by a sound wave transmitter, and the sound waves reflected by the well medium and the formation in the well section are received by a sound wave receiver. The emission position is determined by a positioner.

4. The acoustic logging method for a casing well according to claim 1, characterized in that, The method of converting the defective wave signal into a first electrical control signal, calculating the position of the defective wave signal based on the position signal of the acoustic wave transmitter and the reflected acoustic wave signal, and controlling the acoustic wave transmitter to rotate closer to the position of the defective wave signal includes: When the reflected sound wave is determined to be a defective signal, the position of the defective signal relative to the sound wave transmitter is calculated based on the position signal of the sound wave transmitter and the reflected sound wave signal. The defective signal is then converted into a first electrical control signal and sent to the rotating motor and the telescopic cylinder. The rotating motor is controlled to rotate and the telescopic cylinder is controlled to extend, thereby moving the sound wave transmitter closer to the position of the defective signal.

5. The sonic logging method for a casing well according to claim 1, characterized in that, The method of converting the good wave signal into a second electrical control signal and controlling the sound wave transmitter to rotate back to its original position based on the position signal of the sound wave transmitter includes: When the reflected sound wave is determined to be a good wave signal, the good wave signal is converted into a second electrical control signal and sent to the rotating motor and the telescopic cylinder to control the rotating motor and the telescopic cylinder to return to their original positions. Then, based on the position signal of the sound wave transmitter, it is determined whether the position of the sound wave transmitter has returned to its original position.

6. A sonic logging system for a casing well, used to perform the sonic logging method for a casing well as described in any one of claims 1-5, characterized in that, include: The acquisition module is used to acquire the position signal of the acoustic wave transmitter (101) inside the casing well and the reflected acoustic wave signal; The judgment module is used to determine whether the reflected acoustic signal includes formation wave signals that are not distorted by the well medium; if the reflected acoustic signal does not include formation wave signals that are not distorted by the well medium, it is judged as a bad wave signal; if the reflected acoustic signal includes formation wave signals that are not distorted by the well medium, it is judged as a good wave signal. The conversion module is used to convert the undesirable wave signal into a first electrical control signal, calculate the position of the undesirable wave signal based on the position signal of the acoustic wave transmitter and the reflected acoustic wave signal, and control the acoustic wave transmitter to rotate closer to the position of the undesirable wave signal until a good wave signal is generated; or convert the good wave signal into a second electrical control signal, control the acoustic wave transmitter (101) to rotate back to its original position based on the position signal of the acoustic wave transmitter, and continue logging until the undesirable wave signal is collected again, and repeat the above control steps.

7. The acoustic logging system for a casing well according to claim 6, characterized in that, The acquisition module includes a sound wave transmitter and receiver (1), a connecting rod (2), a rotating motor (3), a telescopic cylinder (4), a positioner (5), and a signal transmission line. The sound wave transmitter and receiver (1) is fitted onto one end of the positioner (5). The other end of the positioner (5) is connected to one end of the connecting rod (2). The other end of the connecting rod (2) is connected to the piston end of the telescopic cylinder (4). The cylinder seat end of the telescopic cylinder (4) is connected to the shaft end of the rotating motor (3). The housing end of the rotating motor (3) is connected to the drill pipe of the casing well. The sound wave transmitter and receiver (1) and the positioner (5) are both connected to the judgment module through the signal transmission line, which is used to send the reflected sound wave signal acquired by the sound wave transmitter and receiver (1) and the position signal measured by the positioner (5) to the judgment module.

8. The acoustic logging system for a casing well according to claim 7, characterized in that, The acoustic wave transmitter and receiver (1) includes an acoustic wave transmitter (101), a helical spring (102), and a spring fixing seat (103). The acoustic wave transmitter (101) is slidably connected to the end of the connecting rod (2) away from the telescopic cylinder (4). The spring fixing seat (103) is connected to the middle of the connecting rod (2). The helical spring (102) is connected between the acoustic wave transmitter (101) and the spring fixing seat (103).

9. The acoustic logging system for a casing well according to claim 8, characterized in that, An anti-collision sensor is provided between the acoustic wave transmitter (101) and the positioner (5).

10. The acoustic logging system for a casing well according to claim 7, characterized in that, The positioner (5) is a GPS wireless positioner.

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