An ultrasonic well logging method, device and apparatus

Abstract

The application relates to the technical field of oil exploration, in particular to an ultrasonic logging method, device and equipment. The ultrasonic logging method comprises the following steps: obtaining the standard thickness of a casing in a well; determining the main frequency of a transmission signal of an ultrasonic transducer according to the standard thickness; controlling the ultrasonic transducer to move in the casing and emit a first ultrasonic signal to the casing at the main frequency of the transmission signal; obtaining a resonance wave signal, which is a second ultrasonic signal reflected back to the ultrasonic transducer after being reflected back and forth between the inner wall and the outer wall of the casing; determining the actual thickness of the casing according to the resonance wave signal; and adjusting the main frequency of the transmission signal according to the actual thickness. Through the above method, the energy of the resonance wave reflected back in the logging process can be ensured, and the detection precision is improved.

Description

Technical Field

[0001] This application relates to the field of petroleum exploration technology, specifically to an ultrasonic logging method, apparatus, and equipment. Background Technology

[0002] During oil extraction, downhole casing is subjected to high temperature and high pressure for a long time, which makes it prone to deformation and corrosion, thereby increasing the risk of oil and gas production operations. Ultrasonic logging technology is an important means of detecting casing integrity problems.

[0003] In ultrasonic transducers, the ultrasonic waves emitted are reflected back and forth by the inner and outer walls of the casing, and the sound waves that are finally reflected back to the transducer are resonant waves. During ultrasonic logging, the resonant wave energy is often weak, which affects the detection accuracy. Summary of the Invention

[0004] In view of the above problems, this application provides an ultrasonic logging method, apparatus and equipment that can ensure the energy of the resonant waves reflected back during the logging process, thereby improving the detection accuracy.

[0005] According to one aspect of this application, an ultrasonic logging method is provided, comprising: obtaining the standard thickness of the casing inside the well; determining the dominant frequency of the transmission signal of an ultrasonic transducer based on the standard thickness; controlling the ultrasonic transducer to move inside the casing and transmitting a first ultrasonic signal to the casing at the dominant frequency of the transmission signal; obtaining a resonance wave signal, wherein the resonance wave signal is a second ultrasonic signal reflected back and forth by the inner and outer walls of the casing and finally reflected back to the ultrasonic transducer; determining the actual thickness of the casing based on the resonance wave signal; and adjusting the dominant frequency of the transmission signal based on the actual thickness.

[0006] In the ultrasonic logging method provided in this application, the main frequency of the ultrasonic transducer's transmission signal is first determined according to the standard thickness of the casing. The ultrasonic transducer is then controlled to transmit ultrasonic waves to the casing at this main frequency and the resonant wave signal reflected back from the casing is obtained. The actual thickness of the casing is determined based on the reflected resonant wave signal. Finally, the main frequency of the ultrasonic transducer's transmission signal is adjusted according to the determined actual thickness to ensure that the adjusted main frequency of the transmission signal is closer to the inherent resonant wave frequency of the casing, thereby enhancing the energy of the received resonant wave and improving the detection accuracy and precision.

[0007] In one optional approach, the dominant frequency of the ultrasonic transducer's transmission signal is determined based on the standard thickness. This includes: acquiring a preset thickness-frequency relationship table, which is a table showing the correspondence between thickness ranges and dominant frequency values; and determining the dominant frequency value corresponding to the thickness range containing the standard thickness in the thickness-frequency relationship table as the dominant frequency of the transmission signal. By determining the dominant frequency of the transmission signal corresponding to the standard thickness based on the preset thickness-frequency relationship table, the amplitude and energy of the resonant wave received by the subsequent ultrasonic transducer can be increased, thereby improving the accuracy of sleeve inspection.

[0008] In one optional approach, the dominant frequency of the transmitted signal is adjusted based on the actual thickness. This includes determining the dominant frequency value corresponding to the thickness range of the actual thickness in the thickness-dominant frequency relationship table as the new dominant frequency of the transmitted signal. By determining the dominant frequency value corresponding to the thickness range of the actual thickness in the thickness-dominant frequency relationship table as the new dominant frequency of the transmitted signal, rapid adjustment of the dominant frequency of the transmitted signal is achieved. Furthermore, for portions of the sleeve where the thickness changes, the amplitude and energy of the resonant wave signal reflected back to the ultrasonic transducer from that portion are improved, thereby facilitating a more accurate analysis of the sleeve's integrity.

[0009] In one optional approach, the thickness-frequency relationship table is determined as follows: Acquiring measurement conditions: acquiring a set of dominant frequencies and a set of standard thicknesses. The set of dominant frequencies includes multiple different transmission signal frequencies, and the set of standard thicknesses includes multiple different standard thicknesses. Transmitting ultrasonic waves: controlling the ultrasonic transducer to transmit a first ultrasonic signal at least once to all casings of standard thicknesses in the standard thickness set at each transmission signal frequency in the set of dominant frequencies. Acquiring results: acquiring a set of resonance wave signals, which includes multiple resonance wave signals. Resonance wave signals are second ultrasonic signals reflected back and forth by the inner and outer walls of the casing during ultrasonic wave transmission and ultimately reflected back to the ultrasonic transducer. One resonance wave signal in the set of resonance wave signals corresponds to one transmission signal frequency in the set of dominant frequencies and one standard thickness in the set of standard thicknesses. Determining the relationship table: determining the thickness-frequency relationship table based on the set of resonance wave signals. Through this method, based on the measured amplitude of the resonance waves, the transmission signal frequency of the ultrasonic transducer can be automatically determined and adjusted according to the standard thickness and actual thickness of the casing during actual well logging operations, thereby ensuring that the received resonance wave amplitude is large, facilitating imaging analysis.

[0010] In one optional approach, determining the relationship table includes: acquiring a set of reflected wave signals, which comprises multiple reflected wave signals. These reflected wave signals are third ultrasonic signals reflected back to the ultrasonic transducer from the inner wall of the sleeve during ultrasonic wave emission. Each reflected wave signal in the set corresponds to a resonant wave signal in the set of resonant wave signals, a dominant frequency of the emitted signal in the set of dominant frequencies, and a standard thickness in the set of standard thicknesses. Based on the resonant wave signals in the set of resonant wave signals and the corresponding reflected wave signals in the set of reflected wave signals, the resonance efficiency is determined. The resonance efficiency is the ratio of the root mean square amplitude of the resonant wave signal to the amplitude of the reflected wave signal. Based on the resonance efficiency, a thickness-dominant frequency relationship table is determined. In this approach, calculating the resonance efficiency allows for a simpler and clearer analysis of the energy magnitude of the resonant wave signals, facilitating the establishment of the thickness-dominant frequency relationship table and subsequent imaging analysis of the sleeve, thereby improving the accuracy of sleeve integrity analysis.

[0011] In one alternative approach, after controlling the ultrasonic transducer to move within the sheath and transmitting a first ultrasonic signal to the sheath at the dominant frequency of the transmission signal, the method further includes: controlling the ultrasonic transducer to discharge rapidly. In this step, after the ultrasonic transducer generates a high-voltage pulse transmission signal, the ultrasonic transducer is controlled to discharge rapidly by a computing device, quickly reducing the voltage on the ultrasonic transducer to 0, thereby suppressing transmission oscillations and reducing the waveform period before the resonant wave signal in the received signal waveform of the ultrasonic transducer.

[0012] According to another aspect of this application, an ultrasonic logging device is provided, comprising: a first acquisition unit for acquiring the standard thickness of the casing inside the well; a first determination unit for determining the main frequency of the transmission signal of an ultrasonic transducer based on the standard thickness; a control unit for controlling the movement of the ultrasonic transducer inside the casing and transmitting a first ultrasonic signal to the casing at the main frequency of the transmission signal; a second acquisition unit for acquiring a resonance wave signal, wherein the resonance wave signal is a second ultrasonic signal reflected back and forth by the inner and outer walls of the casing and finally reflected back to the ultrasonic transducer; a second determination unit for determining the actual thickness of the casing based on the resonance wave signal; and an adjustment unit for adjusting the main frequency of the transmission signal based on the actual thickness.

[0013] According to another aspect of this application, an ultrasonic logging device is provided, comprising: a processor, a memory, a communication interface, and a communication bus, wherein the processor, the memory, and the communication interface communicate with each other through the communication bus; the memory is used to store at least one executable instruction, which causes the processor to execute the ultrasonic logging method as described in any of the above claims.

[0014] In one alternative embodiment, the ultrasonic logging equipment further includes an ultrasonic scanning measurement structure, on which an ultrasonic transducer is mounted. The processor includes a transmission drive circuit connected to the ultrasonic scanning measurement structure. The transmission drive circuit is used to send a control signal to the ultrasonic scanning measurement structure to control the ultrasonic transducer to transmit a first ultrasonic signal to the casing at the main frequency of the transmission signal. The transmission drive circuit is also used to adjust the pulse width of the control signal and to adjust the main frequency of the transmission signal by sending the adjusted control signal to the ultrasonic scanning measurement structure. The transmission drive circuit includes a discharge circuit, which is used to quickly reduce the voltage on the ultrasonic transducer to zero after the transmission drive circuit sends the control signal to the ultrasonic scanning measurement structure.

[0015] In one alternative embodiment, the ultrasonic scanning measurement structure has a mounting portion with multiple mounting positions, such that the distance between the ultrasonic transducer and the axis of the ultrasonic scanning measurement structure is not equal when the ultrasonic transducer is fixed in different mounting positions.

[0016] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0018] Figure 1 A flowchart of the ultrasonic logging method provided in the embodiments of this application;

[0019] Figure 2 A waveform diagram of the transmitted signal of the ultrasonic transducer provided in the embodiments of this application;

[0020] Figure 3 for Figure 1 Flowchart of the sub-steps in step 120;

[0021] Figure 4 for Figure 3 Flowchart of the sub-steps in step 121;

[0022] Figure 5 for Figure 4 Flowchart of the sub-steps in step 1214;

[0023] Figure 6This is a schematic diagram of the ultrasonic logging device provided in the embodiments of this application;

[0024] Figure 7 This is a schematic diagram of the structure of the ultrasonic logging equipment provided in the embodiments of this application;

[0025] Figure 8 A schematic diagram of the transmission drive circuit and ultrasonic scanning measurement structure in the ultrasonic logging equipment provided in this application embodiment;

[0026] Figure 9 This is a cross-sectional schematic diagram of the ultrasonic scanning measurement structure in the ultrasonic logging equipment provided in this application embodiment;

[0027] Figure 10 This is a cross-sectional schematic diagram of the ultrasonic scanning measurement structure with an ultrasonic transducer installed in the ultrasonic logging equipment provided in this application embodiment. Detailed Implementation

[0028] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0029] During oil extraction, downhole tubing and its accessories are subjected to high temperature and pressure for extended periods, making them prone to deformation, corrosion, and sheath spalling, thus increasing safety risks in oil and gas production. Downhole tubing permeation, casing corrosion, and sheath spalling are all significant factors affecting wellbore integrity, and ultrasonic logging is one of the primary methods for detecting wellbore integrity.

[0030] The working method of ultrasonic logging for casing integrity detection is as follows: an ultrasonic transducer is installed on a rotating scanning body. When the rotating scanning body is driven by a drive structure to rotate and move along the depth direction of the casing, the ultrasonic transducer emits ultrasonic signals towards the casing wall. The ultrasonic signals propagate in the well fluid, are reflected back after reaching the casing wall, and are received by the ultrasonic transducer. By analyzing the reflected ultrasonic signals, the integrity of the casing can be detected.

[0031] Specifically, the reflected ultrasonic signal can be divided into two parts. The first part is the reflected wave signal directly reflected from the inner wall of the sheath. This reflected wave signal reflects information about the inner wall of the sheath; for example, the ultrasonic signal amplitude and transmission time can be extracted, and this information can be used to perform characteristic imaging of the inner wall of the sheath and imaging of the inner diameter of the sheath. The second part is the resonant wave signal reflected back and forth from the inner and outer walls of the sheath and finally reflected back to the ultrasonic transducer. This resonant wave signal can be used to calculate the thickness of the sheath. By combining the reflected wave signal and the resonant wave signal, the damage, deformation, and breakage of the sheath can be comprehensively judged.

[0032] Ultrasonic transducers have a certain dominant frequency bandwidth range, and casing has an inherent resonant wave dominant frequency. The inventors of this application have discovered that the resonant wave dominant frequency is different for casings of different thicknesses. When the dominant frequency of the ultrasonic wave emitted by the ultrasonic transducer is closer to the inherent resonant wave dominant frequency of the casing, the energy of the received resonant wave is stronger. However, when the inherent resonant wave dominant frequency of the casing is at the edge or outside the dominant frequency bandwidth range of the ultrasonic wave emitted by the ultrasonic transducer, the resonant wave is weak or even non-existent, which will affect the accuracy and precision of well logging. In particular, when the casing undergoes corrosion, wear, or other changes in thickness, the quality of the resonant wave will be severely affected, thereby affecting the accuracy and precision of the detection.

[0033] To address the aforementioned issues, this application proposes an ultrasonic logging method. First, the dominant frequency of the ultrasonic transducer's transmission signal is determined based on the standard thickness of the casing. The ultrasonic transducer is then controlled to transmit ultrasonic waves to the casing at this dominant frequency and the reflected resonance wave signal is acquired. The actual thickness of the casing is determined based on the reflected resonance wave signal. Finally, the dominant frequency of the ultrasonic transducer's transmission signal is adjusted according to the determined actual thickness to ensure that the adjusted transmission signal frequency is closer to the inherent resonance wave frequency of the casing, thereby enhancing the energy of the received resonance wave and improving detection accuracy and precision.

[0034] Please see Figure 1 The figure illustrates a flowchart of an ultrasonic logging method according to an embodiment of this application. This method is executed by a computing device, such as a computer or server, that performs ultrasonic logging. As shown in the figure, the method includes:

[0035] S110: Obtain the standard thickness of the casing inside the well.

[0036] Since downhole casing comes in various thicknesses and sizes, the standard thickness of the casing in this step can be determined by obtaining the casing model number and then looking up a table showing the correspondence between casing models and standard thicknesses. The casing model number can be input by the user into the calculation device or obtained by retrieving design documents stored in a database.

[0037] S120: Determine the main frequency of the ultrasonic transducer's transmission signal based on the standard thickness.

[0038] Specifically, please refer to Figure 2 The figure shows the waveform of the transmitted signal from the ultrasonic transducer. As shown in the figure, the transmitted signal is a positive and negative pulse signal. If the total duration of the transmitted signal is defined as T, then the dominant frequency f of the transmitted signal is:

[0039]

[0040] In this step, ultrasonic signals can be transmitted to each casing of a standard thickness at least once using different transmission signal frequencies, and the reflected resonance waves can be collected. After testing ultrasonic signals transmitted to the same standard thickness casing at different transmission signal frequencies, the transmission signal frequency corresponding to the resonance wave with the largest amplitude is determined as the transmission signal frequency corresponding to that standard thickness. Then, after pre-setting each standard thickness and its corresponding transmission signal on the computing device, the computing device can determine the transmission signal frequency of the ultrasonic transducer based on the standard thickness of the casing inside the well.

[0041] S130: Control the ultrasonic transducer to move inside the sleeve and transmit the first ultrasonic signal to the sleeve at the main frequency of the above-mentioned transmission signal.

[0042] In this step, the ultrasonic transducer can be controlled to move along the depth direction and rotate circumferentially inside the sleeve, so as to realize the detection of the entire sleeve.

[0043] S140: Acquire the resonance wave signal, which is the second ultrasonic signal reflected back and forth by the inner and outer walls of the sleeve and finally reflected back to the ultrasonic transducer.

[0044] S150: Determine the actual thickness of the sleeve based on the resonance wave signal.

[0045] In this step, THK represents the actual thickness of the sleeve, v represents the speed of sound of the ultrasound in the sleeve, and f represents the dominant frequency of the resonant wave signal. Therefore:

[0046]

[0047] S160: Adjust the main frequency of the transmission signal according to the actual thickness.

[0048] In this step, after the computing device obtains the actual thickness, it can first determine whether the actual thickness is equal to a certain standard thickness in step S120. If so, the main frequency of the transmission signal is adjusted to the main frequency corresponding to the standard thickness that is equal to the actual thickness. If not, the main frequency of the transmission signal corresponding to the standard thickness that is closest to the actual thickness is determined as the new main frequency of the transmission signal after adjustment.

[0049] In the ultrasonic logging method provided in this application, the main frequency of the ultrasonic transducer's transmission signal is first determined according to the standard thickness of the casing. The ultrasonic transducer is then controlled to transmit ultrasonic waves to the casing at this main frequency and the resonant wave signal reflected back from the casing is obtained. The actual thickness of the casing is determined based on the reflected resonant wave signal. Finally, the main frequency of the ultrasonic transducer's transmission signal is adjusted according to the determined actual thickness to ensure that the adjusted main frequency of the transmission signal is closer to the inherent resonant wave frequency of the casing, thereby enhancing the energy of the received resonant wave and improving the detection accuracy and precision.

[0050] Regarding step 120 above, this application further proposes an implementation method, please refer to [link / reference needed]. Figure 3 The diagram illustrates the flow of sub-step 120. As shown in the diagram, step 120 includes:

[0051] S121: Obtain the preset thickness-frequency relationship table, which is a table showing the correspondence between thickness range and frequency value.

[0052] In this step, an ultrasonic signal can be transmitted to each standard thickness sleeve at least once using a different transmission signal frequency, and the reflected resonance wave can be collected. After testing each standard thickness sleeve by transmitting an ultrasonic signal at least once at different transmission signal frequencies, all standard thicknesses are arranged in ascending order, and the average value between two adjacent standard thicknesses is taken. The range between the average values ​​on both sides of each standard thickness is defined as a thickness range. For example, if the standard thicknesses are 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, and 15mm, then the thickness range X includes 7mm≤X1<7.5mm, 7.5mm≤X2<8.5mm, 8.5mm≤X3<9.5mm, 9.5mm≤X4<10.5mm, 10.5mm≤X5<11.5mm, 11.5mm≤X6<12.5mm, 12.5mm≤X7<13.5mm, 13.5mm≤X8<14.5mm, and 14.5mm≤X9≤15mm. After transmitting ultrasonic waves to a sleeve of a certain standard thickness at different transmission signal frequencies and receiving the resonant waves, the transmission signal frequency corresponding to the resonant wave with the largest amplitude is determined as the transmission signal frequency corresponding to the thickness range of the standard thickness, thus forming a thickness frequency relationship table.

[0053] S122: Determine the main frequency value of the standard thickness range in the thickness main frequency relationship table as the main frequency of the transmission signal.

[0054] In this step, by first setting the thickness-frequency relationship table formed in step S121 in the calculation device, the calculation device can determine the main frequency value corresponding to the thickness range of the standard thickness in the thickness-frequency relationship table as the main frequency of the ultrasonic transducer's transmission signal after obtaining the standard thickness.

[0055] By determining the transmission signal frequency corresponding to the standard thickness based on a preset thickness-frequency relationship table, the amplitude and energy of the resonant wave received by the subsequent ultrasonic transducer can be increased, thereby improving the accuracy of sleeve inspection.

[0056] Furthermore, regarding step 160 above, this application proposes an implementation method in which step 160 includes: determining the main frequency value corresponding to the thickness range where the actual thickness is located in the thickness main frequency relationship table as the new transmission signal main frequency.

[0057] By determining the main frequency value corresponding to the thickness range of the actual thickness in the thickness main frequency relationship table as the new transmission signal main frequency, the transmission signal main frequency can be quickly adjusted. Furthermore, for the part where the sleeve thickness changes, the amplitude and energy of the resonant wave signal reflected back to the ultrasonic transducer can be improved, thus facilitating a more accurate analysis of the sleeve integrity in the future.

[0058] Regarding the determination of the thickness-frequency relationship table in step S121 above, this application further proposes an implementation method, please refer to [link to implementation details]. Figure 4 The figure illustrates the method for determining the thickness dominant frequency relationship table in step S121. As shown in the figure, the method for determining the thickness dominant frequency relationship table includes:

[0059] S1211: Obtain measurement conditions: Obtain the set of main frequencies and the set of standard thicknesses. The set of main frequencies includes multiple different transmission signal main frequencies, and the set of standard thicknesses includes multiple different standard thicknesses.

[0060] S1212: Emit ultrasonic waves: Control the ultrasonic transducer to emit a first ultrasonic signal at least once to all sleeves of standard thickness in the standard thickness set at the main frequency of each transmission signal in the main frequency set.

[0061] In steps S1211 and S1212, for example, if the set of main frequencies includes the main frequencies of the transmitted signal f1, f2 and f3, and the set of standard thicknesses includes the standard thicknesses a1, a2 and a3, then the combination of the main frequencies of the transmitted signal and the standard thicknesses (i.e., transmitting the first ultrasonic signal to the sleeve of the standard thickness at the main frequency of the transmitted signal) includes f1a1, f2a1, f3a1, f1a2, f2a2, f3a2, f1a3, f2a3 and f3a3.

[0062] S1213: Obtain the result: Obtain the set of resonant wave signals. The set of resonant wave signals includes multiple resonant wave signals. The resonant wave signals are the second ultrasonic signals that are reflected back and forth by the inner and outer walls of the sleeve and finally reflected back to the ultrasonic transducer during the above step S1212. One resonant wave signal in the set of resonant wave signals corresponds to one transmission signal main frequency in the set of main frequencies and one standard thickness in the set of standard thicknesses.

[0063] In this step, for example, the combination of the main frequency of the transmitted signal and the standard thickness is as described above, including f1a1, f2a1, f3a1, f1a2, f2a2, f3a2, f1a3, f2a3 and f3a3. Each combination will receive a resonant wave signal. These resonant wave signals together form a resonant wave signal set, which is represented by Q. The resonant wave signal set includes Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8 and Q9, which correspond to the above combinations in sequence.

[0064] S1214: Determine the relationship table: Based on the set of resonant waves, determine the thickness-dominant frequency relationship table.

[0065] In this step, taking the combination of the aforementioned transmission signal frequency and standard thickness, along with the set of resonant wave signals, as an example, the resonant wave signals corresponding to standard thickness a1 are Q1, Q2, and Q3; those corresponding to standard thickness a2 are Q4, Q5, and Q6; and those corresponding to standard thickness a3 are Q7, Q8, and Q9. The transmission signal frequency for the sleeve with standard thickness a1 can be determined by comparing the amplitudes of Q1, Q2, and Q3. For example, when the amplitude of Q2 is the largest, the transmission signal frequency f2 is determined as the transmission signal frequency for detecting the sleeve with standard thickness a1. The same logic applies to sleeves with standard thicknesses a2 and a3.

[0066] Considering that the actual thickness value in subsequent step S160 may differ from the standard thickness value of the sleeve when wear or corrosion occurs, to ensure the accuracy of sleeve detection, the standard thicknesses are arranged in ascending order. Using the example above, assuming a1 < a2 < a3, the average of adjacent standard thicknesses is taken, with a1 < a2 < a3. 12 This represents the average of a1 and a2, where a 23 If X represents the average of a2 and a3, then the thickness range X can be a1 ≤ X1 < a 12 a 12 ≤X2<a 23 and a 23 ≤X3≤a3, but it can also be a1≤X1≤a 12 a 12 <X2<a23 and a 23 ≤X3≤a3. As mentioned above, for example, if Q2 has the largest amplitude, then the main frequency f2 is determined as the main frequency of the transmission signal for detecting sleeves of all thicknesses within the thickness range X1. The same applies to thickness ranges X2 and X3.

[0067] By using the above method, based on the measured amplitude of the resonance wave, the main frequency of the ultrasonic transducer's transmission signal can be automatically determined and adjusted according to the standard thickness and actual thickness of the casing during actual well logging operations, thereby ensuring that the received resonance wave has a large amplitude, which is convenient for imaging analysis.

[0068] Regarding step S1214 above, this application further proposes an implementation method, please refer to [link / reference needed]. Figure 5 The diagram illustrates the flow of sub-step S1214. As shown in the diagram, step S1214 includes:

[0069] S12141: Obtain a set of reflected wave signals. The set of reflected wave signals includes multiple reflected wave signals. The reflected wave signals are the third ultrasonic signals reflected back to the ultrasonic transducer from the inner wall of the sleeve during the above step S1212. One reflected wave signal in the set of reflected wave signals corresponds to one resonant wave signal in the set of resonant wave signals, one main frequency of the transmission signal in the set of main frequencies, and one standard thickness in the set of standard thicknesses.

[0070] In this step, after an ultrasonic wave is emitted once to the sleeve at a main frequency of a transmission signal, the ultrasonic transducer will receive a reflected wave and a resonant wave. By emitting a first ultrasonic signal at least once to all sleeves of standard thickness in the standard thickness set at each main frequency of the transmission signal set in step S1212, multiple reflected wave signals can be obtained, and the multiple reflected wave signals form the set of reflected wave signals.

[0071] S12142: Determine the resonance efficiency based on the resonance wave signal in the set of resonance wave signals and the reflected wave signal in the set of reflected wave signals corresponding to it. The resonance efficiency is the ratio of the root mean square amplitude of the resonance wave signal to the amplitude of the reflected wave signal.

[0072] Resonance efficiency is used to represent the relative magnitude of the energy of the resonant wave. For example, a resonance efficiency of 0.05 means that if the energy of the first ultrasonic signal reflected back from the inner wall of the cannula is 100, then the energy converted into a resonant wave is 5.

[0073] S12143: Determine the thickness-frequency relationship table based on the resonance efficiency.

[0074] In one specific embodiment, the resonance efficiency results of the ultrasonic transducer with a center frequency of 250kHz, measured at the main frequencies of the transmitted signals of 200kHz, 250kHz, and 400kHz, through the above steps S1211, S1212, S1213, S12141, and S12142, are shown in Table 1 below:

[0075] Table 1

[0076]

[0077] As shown in Table 1, when the sleeve thickness is 13mm, 14mm, and 15mm, the resonant efficiency is highest at a transmitting signal frequency of 200kHz, with values ​​of 0.067, 0.062, and 0.064, respectively. When the sleeve thickness is 10mm, 11mm, and 12mm, the resonant efficiency is highest at a transmitting signal frequency of 250kHz, with values ​​of 0.063, 0.063, and 0.069, respectively. When the sleeve thickness is 7mm, 8mm, and 9mm, the resonant efficiency is highest at a transmitting signal frequency of 400kHz, with values ​​of 0.042, 0.054, and 0.061, respectively.

[0078] Based on the above results, the thickness-frequency relationship table can be determined as shown in Table 2 below:

[0079] Table 2

[0080] Thickness range X (mm) Transmitted signal frequency (kHz) 7≤X＜10.5 400 10.5≤X＜12.5 250 12.5≤X≤15 200

[0081] It should be noted that the above thickness-frequency relationship table is only provided for the convenience of explanation as one possible method, and does not limit the specific content of the thickness-frequency relationship table. The specific thickness range and the relationship between the transmission signal frequency can be adjusted according to the number of sleeves of standard thickness tested in other embodiments, the center frequency of the tested ultrasonic transducer, and the transmission signal frequency data of the tested ultrasonic transducer. It will not be elaborated here.

[0082] In the above method, by calculating the resonance efficiency, the energy magnitude of the resonance wave signal can be analyzed more simply and clearly, which facilitates the establishment of the thickness-frequency relationship table and subsequent imaging analysis of the sleeve, and helps to improve the accuracy of the sleeve integrity analysis.

[0083] In some embodiments, after step S130, the method further includes: controlling the ultrasonic transducer to discharge rapidly.

[0084] Because ultrasonic transducers exhibit capacitive or inductive load characteristics during operation, it takes a certain amount of time for the ultrasonic transducer to change from a high-voltage state to a zero-level state, and subsequent oscillations will occur, thereby affecting the bandwidth of the ultrasonic transmitted signal and the waveform period of the reflected wave signal.

[0085] In this step, after the ultrasonic transducer generates a high-voltage pulse transmission signal, the computing device controls the ultrasonic transducer to discharge rapidly, quickly reducing the voltage on the ultrasonic transducer to 0, thereby suppressing transmission oscillation and reducing the waveform period before the resonant wave signal in the received signal waveform of the ultrasonic transducer.

[0086] The acoustic impedance of the casing material can be calculated based on the resonance wave amplitude information, which can then be used to determine the cement bonding condition and identify the cement return point. In high-density oil-based drilling mud, the ultrasonic signal is very weak; therefore, the ultrasonic transducer uses high sensitivity and high voltage to transmit the signal to improve its strength. However, in low-density well fluids, this can cause clipping distortion of the reflected wave signal, affecting the detection results of the casing inner wall and the acoustic impedance measurement of the casing material. When the transmission signal duty cycle is not 100%, during the "empty" period of the transmission signal, the duty cycle of the transmitted pulse signal can be adjusted by controlling the voltage drop of the ultrasonic transducer to 0, thereby avoiding distortion caused by excessively strong reflected wave signals.

[0087] According to another aspect of the embodiments of this application, an ultrasonic logging device is provided, please refer to [the specific details]. Figure 6 The figure shows the structure of an ultrasonic logging device provided in one embodiment. As shown, the ultrasonic logging device 200 includes: a first acquisition unit 210, a first determination unit 220, a control unit 230, a second acquisition unit 240, a second determination unit 250, and an adjustment unit 260. The first acquisition unit 210 is used to acquire the standard thickness of the casing inside the well. The first determination unit 220 is used to determine the dominant frequency of the ultrasonic transducer's transmission signal based on the standard thickness. The control unit 230 is used to control the movement of the ultrasonic transducer inside the casing and to transmit a first ultrasonic signal to the casing at the aforementioned dominant transmission signal frequency. The second acquisition unit 240 is used to acquire a resonance wave signal, which is a second ultrasonic signal reflected back to the ultrasonic transducer by the inner and outer walls of the casing. The second determination unit 250 is used to determine the actual thickness of the casing based on the resonance wave signal. The adjustment unit 260 is used to adjust the dominant frequency of the transmission signal based on the actual thickness.

[0088] In one optional approach, the first determining unit 220 is used to obtain a preset thickness-frequency relationship table, which is a correspondence table between thickness range and frequency value, and is used to determine the frequency value corresponding to the thickness range where the standard thickness is located in the thickness-frequency relationship table as the main frequency of the transmission signal.

[0089] In one alternative approach, the second determining unit 250 is used to determine the main frequency value corresponding to the thickness range where the actual thickness is located in the thickness main frequency relationship table as the new transmission signal main frequency.

[0090] In one alternative approach, the first determining unit 220 is used to acquire measurement conditions: acquire a set of dominant frequencies and a set of standard thicknesses, the set of dominant frequencies including multiple different transmission signal frequencies, and the set of standard thicknesses including multiple different standard thicknesses, for transmitting ultrasonic waves: control the ultrasonic transducer to transmit a first ultrasonic signal at least once to all sleeves of standard thicknesses in the set of standard thicknesses at each transmission signal frequency in the set of dominant frequencies, for acquiring results: acquire a set of resonant wave signals, the set of resonant wave signals including multiple resonant wave signals, the resonant wave signals being second ultrasonic signals reflected back and forth by the inner and outer walls of the sleeve and finally reflected back to the ultrasonic transducer during the above ultrasonic wave transmission steps, one resonant wave signal in the set of resonant wave signals corresponding to one transmission signal frequency in the set of dominant frequencies and one standard thickness in the set of standard thicknesses, for determining a relationship table: determine a thickness-dominant frequency relationship table based on the set of resonant waves.

[0091] In one optional embodiment, the first determining unit 220 is used to acquire a set of reflected wave signals, which includes multiple reflected wave signals. The reflected wave signals are the third ultrasonic signals reflected back to the ultrasonic transducer from the inner wall of the sleeve during the above step S1212. Each reflected wave signal in the set of reflected wave signals corresponds to a resonant wave signal in the set of resonant wave signals, a main frequency of the transmitted signal in the set of main frequencies, and a standard thickness in the set of standard thicknesses. The unit is used to determine the resonance efficiency based on the resonant wave signals in the set of resonant wave signals and the reflected wave signals in the set of reflected wave signals corresponding to them. The resonance efficiency is the ratio of the root mean square amplitude of the resonant wave signal to the amplitude of the reflected wave signal. The unit is used to determine the thickness-main frequency relationship table based on the resonance efficiency.

[0092] Please refer to it again. Figure 6 As shown in the figure, in one optional embodiment, the ultrasonic logging device 200 further includes a rapid discharge unit 270. After the control unit 230 controls the ultrasonic transducer to move inside the casing and emits a first ultrasonic signal to the casing, the rapid discharge unit 270 is used to control the ultrasonic transducer to discharge rapidly.

[0093] According to another aspect of the embodiments of this application, an ultrasonic logging device is also provided, please refer to [link / reference needed]. Figure 7 The figure shows the structure of an ultrasonic logging device provided in one embodiment. The specific embodiments of this application do not limit the specific implementation of the ultrasonic logging device.

[0094] like Figure 7 As shown, the ultrasonic logging equipment may include: a processor 302, a communications interface 304, a memory 306, and a communications bus 308.

[0095] The processor 302, communication interface 304, and memory 306 communicate with each other via communication bus 308. Communication interface 304 is used to communicate with other network elements, such as clients or other servers. The processor 302 executes program 310, specifically performing the relevant steps described in the ultrasonic logging method embodiment.

[0096] Specifically, program 310 may include program code, which includes computer-executable instructions.

[0097] Processor 302 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention. The ultrasonic logging equipment includes one or more processors, which may be of the same type, such as one or more CPUs; or they may be of different types, such as one or more CPUs and one or more ASICs.

[0098] Memory 306 is used to store program 310. Memory 306 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0099] Specifically, program 310 can be called by processor 302 to cause the ultrasonic logging equipment to perform the following operations:

[0100] Obtain the standard thickness of the casing inside the well;

[0101] Determine the main frequency of the ultrasonic transducer's transmission signal based on the standard thickness;

[0102] Control the movement of the ultrasonic transducer inside the sheath and transmit the first ultrasonic signal to the sheath at the main frequency of the aforementioned transmission signal.

[0103] Acquire the resonance wave signal, which is the second ultrasonic signal reflected back and forth by the inner and outer walls of the sleeve and finally reflected back to the ultrasonic transducer;

[0104] The actual thickness of the sleeve is determined based on the resonance wave signal;

[0105] Adjust the main frequency of the transmitted signal according to the actual thickness.

[0106] Please see Figure 8The figure shows a partial circuit structure of an ultrasonic logging device provided in one embodiment. As shown in the figure, in some embodiments, the processor 302 includes a transmit drive circuit 311, and the ultrasonic logging device also includes an ultrasonic scanning measurement structure 312, on which an ultrasonic transducer is disposed. The transmit drive circuit 311 is connected to the ultrasonic scanning measurement structure 312. The transmit drive circuit 311 is used to send a control signal to the ultrasonic scanning measurement structure 312 to control the ultrasonic transducer to transmit an ultrasonic signal to the casing at the main frequency of the aforementioned transmit signal. The transmit drive circuit 311 is also used to adjust the pulse width of the control signal and adjust the main frequency of the ultrasonic transducer's transmit signal by sending the adjusted control signal to the ultrasonic scanning measurement structure 312. The transmit drive circuit 311 includes a discharge circuit 3111, which is used to quickly reduce the voltage on the ultrasonic transducer to zero after the transmit drive circuit 311 sends the control signal to the ultrasonic scanning measurement structure 312.

[0107] like Figure 8 As shown, the control signals can be generated by the DSP chip TMS320F28335. There are three control signals: EPWM1A, EPWM1B, and EPWM2A. The EPWM1 ​​module of the TMS320F28335 chip's EPWM (Enhanced Pulse Width Modulator) module outputs EPWM1A, which is the positive pulse control signal for the transmitting circuit, used to control the duration of the positive pulse of the transmitted signal. EPWM2 is the negative pulse control signal, used to control the duration of the negative pulse of the transmitted signal. EPWM2A is the return-to-zero control signal, used to control the rapid discharge after the transmitted signal and the low-level time during duty cycle adjustment of the transmitted signal.

[0108] By setting the time base counting period (TPPRD), counting comparator A (CMPA), technical comparator B (CMPB), and counting mode of the EPWM module, the timing and level width of EPWM1A and EPWM1B can be controlled, thereby controlling and adjusting the positive and negative pulse widths of the control signal, and realizing the control and adjustment of the main frequency of the ultrasonic transducer's transmission signal.

[0109] Figure 8 Q1 and Q2 are N-type MOSFETs. Q1 generates a positive high-voltage pulse, and Q2 generates a negative high-voltage pulse to control the ultrasonic transducer. Because the ultrasonic transducer exhibits capacitive or inductive load characteristics during operation, there is a time delay between the high-voltage state and the zero-level state, and subsequent oscillations occur, affecting the bandwidth of the control signal and the waveform period of the reflected wave signal. Therefore, as... Figure 8As shown, the isolation drive module 3112 is connected to a discharge circuit 3111. In the discharge circuit 3111, Q is a P-type MOSFET and Q4 is an N-type MOSFET. After generating a high-voltage pulse transmission signal, the ultrasonic transducer can be rapidly discharged through Q3 and Q4 to quickly reduce the voltage on the ultrasonic transducer to 0, thereby suppressing transmission oscillation and reducing the waveform period before the resonance wave in the received waveform of the ultrasonic transducer. Furthermore, when the duty cycle of the transmission signal is not 100%, when the transmission signal is in the "empty" period, the zero-reset control signal (EPWM2A) can quickly adjust the voltage of the transducer to 0, thereby adjusting the duty cycle of the transmission signal and avoiding distortion caused by excessively strong reflected wave signals.

[0110] Please see Figure 9 and Figure 10 The figures show cross-sectional views of an ultrasonic scanning measurement structure provided in one embodiment of this application and a cross-sectional view of an ultrasonic scanning measurement structure with an ultrasonic transducer mounted thereon. In some embodiments, the ultrasonic scanning measurement structure 312 has a mounting portion 3121, which has multiple mounting positions 3121a, such that when the ultrasonic transducer 313 is fixed at different mounting positions 3121a, the distance between the ultrasonic transducer 313 and the axis 312a of the ultrasonic scanning measurement structure 312 is not equal.

[0111] During ultrasonic logging, the ultrasonic transducer 313 needs to maintain a certain distance from the wellbore. If the distance is too small, the secondary reflections of the ultrasonic waves on the wellbore will cause aliasing between the secondary and primary reflection waveforms. If the distance is too large, the ultrasonic waves will attenuate more in the well fluid, resulting in a weaker signal. Therefore, a suitable distance needs to be maintained between the ultrasonic transducer 313 and the wellbore. Different types of well fluids have different ultrasonic wave transmission speeds and attenuation characteristics; therefore, the optimal distance between the ultrasonic transducer 313 and the wellbore will also differ depending on the type of well fluid.

[0112] This application provides multiple mounting positions 3121a on the mounting part 3121 of the ultrasonic scanning measurement structure 312, so that when the ultrasonic transducer 313 is fixed in different mounting positions, the distance between the ultrasonic transducer 313 and the axis 312a of the ultrasonic scanning measurement structure 312 is not equal. That is, the distance between the ultrasonic transducer 313 and the well wall is adjusted, so that the ultrasonic transducer 313 can be installed in a suitable mounting position 3121a for different casings and well fluids, ensuring signal quality and improving measurement accuracy.

[0113] The algorithms or displays provided herein are not inherently related to any particular computer, virtual system, or other device. Various general-purpose systems can also be used in conjunction with the teachings herein. The required structure for constructing such systems is apparent from the above description. Furthermore, the embodiments of the present invention are not directed to any particular programming language. It should be understood that the content of the invention described herein can be implemented using various programming languages, and the above description of specific languages ​​is for the purpose of disclosing the best mode of implementation of the invention.

[0114] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0115] Similarly, it should be understood that, in order to streamline the invention and aid in understanding one or more of the various aspects of the invention, features of the embodiments of the invention are sometimes grouped together in a single embodiment, figure, or description thereof in the above description of exemplary embodiments of the invention. However, this disclosure should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim.

[0116] Those skilled in the art will understand that modules in the device of the embodiments can be adaptively changed and placed in one or more devices different from that embodiment. Modules, units, or components in the embodiments can be combined into a single module, unit, or component, and can be divided into multiple sub-modules, sub-units, or sub-components. Except where at least some of such features and / or processes or units are mutually exclusive, any combination can be used to combine all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or device so disclosed. Unless expressly stated otherwise, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0117] It should be noted that the above embodiments are illustrative of the invention and not restrictive, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names. The steps in the above embodiments, unless otherwise specified, should not be construed as limiting the order of execution.

Claims

1. An ultrasonic logging method, characterized in that, include: Obtain the standard thickness of the casing inside the well; The dominant frequency of the ultrasonic transducer's transmission signal is determined based on the standard thickness. The ultrasonic transducer is controlled to move inside the sleeve and transmits a first ultrasonic signal to the sleeve at the main frequency of the transmission signal. Acquire a resonance wave signal, wherein the resonance wave signal is a second ultrasonic signal that is reflected back and forth by the inner and outer walls of the sleeve and finally reflected back to the ultrasonic transducer; The actual thickness of the sleeve is determined based on the resonant wave signal. The actual thickness of the sleeve is equal to the speed of sound of the ultrasonic wave in the sleeve divided by twice the dominant frequency of the resonant wave signal. Adjust the main frequency of the transmitted signal according to the actual thickness; Determining the dominant frequency of the ultrasonic transducer's transmission signal based on the standard thickness includes: Obtain a preset thickness-frequency relationship table, which is a table showing the correspondence between thickness range and frequency value; The main frequency value corresponding to the thickness range containing the standard thickness in the thickness main frequency relationship table is determined as the main frequency of the transmitted signal; The step of adjusting the main frequency of the transmitted signal based on the actual thickness includes: The thickness range containing the actual thickness is determined as the corresponding frequency value in the thickness frequency relationship table, which is then used as the new transmission signal frequency.

2. The ultrasonic logging method according to claim 1, characterized in that, The thickness-frequency relationship table is determined in the following ways: Measurement conditions: Obtain a set of main frequencies and a set of standard thicknesses, wherein the set of main frequencies includes multiple different main frequencies of the transmitted signals, and the set of standard thicknesses includes multiple different standard thicknesses; Emitting ultrasonic waves: Controlling the ultrasonic transducer to emit the first ultrasonic signal at least once to each of the standard thicknesses in the standard thickness set at the main frequency of each of the main transmission signals in the main frequency set; Results obtained: A set of resonant wave signals is obtained, which includes multiple resonant wave signals. The resonant wave signals are the second ultrasonic signals that are reflected back and forth by the inner and outer walls of the sleeve and finally reflected back to the ultrasonic transducer when the ultrasonic waves are emitted. One of the resonant wave signals in the set of resonant wave signals corresponds to one of the main frequencies of the emitted signal in the set of main frequencies and one of the standard thicknesses in the set of standard thicknesses. Determine the relationship table: Based on the set of resonant wave signals, determine the thickness main frequency relationship table.

3. The ultrasonic logging method according to claim 2, characterized in that, The defined relationship table includes: A set of reflected wave signals is obtained, the set of reflected wave signals includes multiple reflected wave signals, the reflected wave signals are the third ultrasonic signals reflected back to the ultrasonic transducer by the inner wall of the sleeve when the ultrasonic wave is emitted, and one of the reflected wave signals in the set of reflected wave signals corresponds to one of the resonant wave signals in the set of resonant wave signals, one of the main frequencies of the emitted signal in the set of main frequencies, and one of the standard thicknesses in the set of standard thicknesses; The resonance efficiency is determined based on the resonant wave signal in the resonant wave signal set and the reflected wave signal in the corresponding reflected wave signal set. The resonance efficiency is the ratio of the root mean square amplitude of the resonant wave signal to the amplitude of the reflected wave signal. Based on the resonance efficiency, determine the thickness-frequency relationship table.

4. The ultrasonic logging method according to claim 1, characterized in that, After controlling the ultrasonic transducer to move within the sheath and transmitting a first ultrasonic signal to the sheath at the main frequency of the transmission signal, the method further includes: Control the ultrasonic transducer to discharge rapidly.

5. An ultrasonic logging device, characterized in that, include: The first acquisition unit is used to acquire the standard thickness of the casing inside the well. The first determining unit is used to determine the main frequency of the ultrasonic transducer's transmission signal based on the standard thickness. A control unit is used to control the movement of the ultrasonic transducer inside the sleeve and to transmit a first ultrasonic signal to the sleeve at the main frequency of the transmission signal. The second acquisition unit acquires a resonance wave signal, which is a second ultrasonic signal that is reflected back and forth by the inner and outer walls of the sleeve and finally reflected back to the ultrasonic transducer. The second determining unit is used to determine the actual thickness of the sleeve based on the resonant wave signal. The actual thickness of the sleeve is equal to the speed of sound of the ultrasonic wave in the sleeve divided by twice the dominant frequency of the resonant wave signal. The adjustment unit adjusts the main frequency of the transmitted signal according to the actual thickness. The first determining unit determines the dominant frequency of the ultrasonic transducer's transmission signal based on the standard thickness, including: Obtain a preset thickness-frequency relationship table, which is a table showing the correspondence between thickness range and frequency value; The main frequency value corresponding to the thickness range containing the standard thickness in the thickness main frequency relationship table is determined as the main frequency of the transmitted signal; The adjustment unit adjusts the main frequency of the transmitted signal according to the actual thickness, including: The thickness range containing the actual thickness is determined as the corresponding frequency value in the thickness frequency relationship table, which is then used as the new transmission signal frequency.

6. An ultrasonic logging device, characterized in that, include: The processor, memory, communication interface, and communication bus are provided, wherein the processor, memory, and communication interface communicate with each other via the communication bus. The memory is used to store at least one executable instruction that causes the processor to execute the ultrasonic logging method as described in any one of claims 1-4.

7. The ultrasonic logging equipment according to claim 6, characterized in that, The ultrasonic logging equipment also includes an ultrasonic scanning measurement structure, on which the ultrasonic transducer is installed, and the processor includes a transmission drive circuit, which is connected to the ultrasonic scanning measurement structure. The transmission drive circuit is used to send a control signal to the ultrasonic scanning measurement structure to control the ultrasonic transducer to transmit the first ultrasonic signal to the sheath at the main frequency of the transmission signal. The transmission drive circuit is also used to adjust the pulse width of the control signal and adjust the main frequency of the transmission signal by sending the adjusted control signal to the ultrasonic scanning measurement structure. The transmission drive circuit includes a discharge circuit, which is used to quickly reduce the voltage on the ultrasonic transducer to zero after the transmission drive circuit sends the control signal to the ultrasonic scanning measurement structure.

8. The ultrasonic logging equipment according to claim 7, characterized in that, The ultrasonic scanning measurement structure has a mounting part with multiple mounting positions, such that when the ultrasonic transducer is fixed in different mounting positions, the distance between the ultrasonic transducer and the axis of the ultrasonic scanning measurement structure is not equal.

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