Rotary scanning well logging acoustic system for underground multi-mode ultrasonic guided wave signal measurement

Abstract

The invention provides a rotary scanning well logging acoustic system for underground multi-mode ultrasonic guided wave signal measurement, and relates to the technical field of oil-gas exploration and development, and the rotary scanning well logging acoustic system comprises a bearing skeleton which is used for dynamically adjusting the gravity center of the acoustic system; the circuit module is arranged on the bearing framework; the ultrasonic transducer group is arranged on the bearing framework and is connected with the circuit module; and the transmission bus is used for supporting the circuit modules to carry out interconnection communication. The method is applied to development of ultrasonic scanning imaging logging instruments and has remarkable advantages in the aspects of uniform high-speed rotation measurement, close-range electrical connection, interference noise weakening and the like, and the signal-to-noise ratio of underground multimode ultrasonic guided wave signal measurement data and the logging success rate are increased.

Description

Technical Field

[0001] This invention relates to the field of oil and gas exploration and development technology, and is applied to casing well imaging logging technology. Specifically, it relates to a rotating scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement. Background Technology

[0002] In the field of oil and gas exploration and development, the quality of cement cementing and the condition of casing damage directly affect the safe production and life cycle of oil and gas wells. Measuring the amplitude or attenuation changes of ultrasonic guided waves in the casing is an important logging method for detecting and evaluating the quality of cement bonding and the condition of casing damage. The casing-cement sheath-formation constitute a radially layered fluid-filled wellbore acoustic waveguide. The guided waves in the casing include zero-order symmetric Lamb wave S0 guided wave, zero-order antisymmetric Lamb wave A0 guided wave, first-order symmetric Lamb wave S1 guided wave, and higher-order symmetric Lamb waves S2 and S3 guided waves.

[0003] In recent years, several domestic and international oilfield service companies have combined the attenuation of A0 guided waves with the amplitude or attenuation and spectrum of S1 guided waves to develop cement sheath-sealed imaging logging instruments. Examples include Schlumberger's IBC (Imaging BehindCasing) and CNOOC's UCCS (Ultrasonic Corrosion and Cement Bonding Scanner). The key to these instruments is a rotating scanning logging acoustic system equipped with multiple ultrasonic transducers. This system can evaluate cement bond quality and casing damage, as well as invert the gas-liquid-solid phase state of the external casing medium. Furthermore, the measurement results are unaffected by cement density, effectively improving the evaluation of low-density cement bond quality.

[0004] However, in existing technologies, rotating scanning logging acoustic systems include four ultrasonic transducers. One self-transmitting and self-receiving ultrasonic transducer is placed vertically on one side of the instrument, while the other three ultrasonic transducers (one transmitter and two receivers) are arranged at a certain tilt angle on the other side of the instrument, forming a one-transmitter, two-receiver logging acoustic system with a source-to-source distance of 25 cm and a spacing of 10 cm. Due to the uneven distribution of the ultrasonic transducers on both sides and the requirement for a specific source-to-source distance, the center of gravity of the rotating scanning logging acoustic system deviates from the rotation axis. During high-speed scanning logging, this easily leads to lateral vibration and non-uniform eccentric rotation, severely affecting the quality of logging data and the success rate of logging. Therefore, in the structural design of rotating scanning logging acoustic systems, counterweights or pressure balancing structures are often used to address the problem of center of gravity deviation. However, this design of adding counterweights or pressure balancing structures not only occupies space in the rotating scanning logging acoustic system but also makes it difficult to lay long-distance through-wires.

[0005] In existing technologies, cement sheath-sealed imaging logging instruments separate the electronic compartment sub and the rotary scanning acoustic system into two independent subsections, separated by a roller stabilizer and a rotary actuator. This necessitates the use of long-distance (greater than 2.5m) and numerous through-wires for the electrical connection between the excitation acquisition circuit and the rotary scanning logging acoustic system. This inevitably introduces strong noise interference into the measurement of ultrasonic mode wave signals in the frequency range of 200–700kHz, as well as crosstalk between multi-channel analog signal transmissions, thus significantly reducing the signal-to-noise ratio of the logging data.

[0006] Therefore, how to realize a rotating scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement that can rotate at a constant speed and high speed downhole while also being electrically connected to the excitation acquisition circuit at close range is an urgent technical problem to be solved.

[0007] To address the problems of existing technologies, this invention provides a rotating scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement. Summary of the Invention

[0008] To overcome the shortcomings of existing technologies, a rotary scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement is provided. This system overcomes the deficiencies of existing technologies, such as the counterweight occupying wiring space, the center of gravity deviation causing non-uniform rotation, and the introduction of strong noise interference by a large number of long-distance wiring. It also solves the problems of uniform high-speed rotation of the rotary scanning logging acoustic system in the high temperature, high pressure, and confined space of downhole wells, as well as close electrical connection with the excitation acquisition circuit, thereby improving the signal-to-noise ratio and logging success rate of downhole multimode ultrasonic guided wave signal measurement data.

[0009] This invention provides a rotating scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement, the acoustic system comprising:

[0010] A supporting frame, which is used to dynamically adjust the center of gravity of the acoustic system;

[0011] The circuit module is disposed on the supporting frame;

[0012] An ultrasonic transducer assembly is mounted on the supporting frame and connected to the circuit module;

[0013] A transmission bus is used to support interconnection and communication between the circuit modules.

[0014] According to one embodiment of the present invention, the load-bearing frame comprises:

[0015] The supporting prism is used to house the circuit module and the ultrasonic transducer assembly, and also to dynamically adjust the center of gravity of the acoustic system.

[0016] An upper electrical connector is located at one end of the supporting prism and is used to achieve electrical connection;

[0017] The lower end protective joint is located at the other end of the load-bearing prism and is used to protect the load-bearing frame.

[0018] According to one embodiment of the present invention, the supporting prism includes slots for arranging the ultrasonic transducer assembly and cavities for arranging the circuit module, wherein the circuit module is connected to the ultrasonic transducer assembly via high-temperature wires.

[0019] According to one embodiment of the present invention, the internal cavity of the supporting prism is filled with hydraulic oil, and a balance piston is respectively provided at the inlet end and the outlet end of the internal cavity to dynamically adjust the center of gravity of the acoustic system. An oil injection plug is also provided at the inlet end of the internal cavity.

[0020] According to one embodiment of the present invention, each ultrasonic transducer in the ultrasonic transducer group has a sealing ring nested on its outer surface and directly inserted into the corresponding slot. Each ultrasonic transducer is fitted with an elastic retaining ring on its outer side to restrict its movement to the external drilling fluid. Each ultrasonic transducer is connected to the multi-core connector of the circuit module through the high-temperature wire.

[0021] According to one embodiment of the present invention, the ultrasonic transducer group comprises: a transceiver ultrasonic transducer, a transmitting ultrasonic transducer, and at least two receiving ultrasonic transducers, wherein:

[0022] The transceiver ultrasonic transducer is used for self-transmitting and receiving ultrasonic pulse reflection echoes and S1 guided wave signals in a vertical manner.

[0023] One of the transmitting ultrasonic transducers and at least two of the receiving ultrasonic transducers constitute a one-to-many logging mode for inclined transmission and reception of ultrasonic pulse A0 guided wave signals and subsequent reflected waves.

[0024] According to one embodiment of the present invention, the circuit module includes:

[0025] An excitation circuit is used to generate high-voltage pulses to synchronously excite the transceiver ultrasonic transducer and the transmitting ultrasonic transducer.

[0026] The acquisition circuit includes at least two independent, fully parallel acquisition channels for digitally acquiring ultrasonic guided wave signals received by at least two of the receiving ultrasonic transducers in parallel.

[0027] A data buffer circuit is used to store the digitized ultrasonic guided wave signal output by the acquisition circuit;

[0028] A power conversion circuit is used to supply power to the circuit module;

[0029] A control circuit is used to control the excitation circuit, the acquisition circuit, the data buffer circuit, and the power conversion circuit.

[0030] According to one embodiment of the present invention, the circuit module is interconnected with the main control electronic compartment via the transmission bus, and the main control electronic compartment also transmits electrical energy to the circuit module via a multi-core wire.

[0031] According to another aspect of the present invention, a rotating scanning logging method for measuring downhole multimode ultrasonic guided wave signals is also provided, executed by an acoustic system as described in any of the preceding claims, the method comprising:

[0032] The ultrasonic signal is emitted, wherein the ultrasonic signal includes a vertical ultrasonic signal and an inclined ultrasonic signal, the emission direction of the vertical ultrasonic signal is perpendicular to the axis of the acoustic system, and the emission direction of the inclined ultrasonic signal has a preset tilt angle with the axis of the acoustic system.

[0033] Receive feedback signals, wherein the feedback signals include A0 guided wave signals and S1 guided wave signals.

[0034] According to another aspect of the invention, a storage medium is also provided, which includes instructions for performing the methods described above.

[0035] This invention provides a rotary scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement. Compared with the prior art, it has the following advantages: Addressing the shortcomings of existing rotary scanning logging acoustic systems for casing well logging, such as non-uniform rotation due to center-of-gravity deviation, limited wiring space, and strong noise interference introduced by long-distance wiring, this invention provides a rotary scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement. When applied to the development of ultrasonic scanning imaging logging instruments, it exhibits significant advantages in uniform high-speed rotation measurement, close-range electrical connections, and noise reduction, thereby improving the signal-to-noise ratio and logging success rate of downhole multimode ultrasonic guided wave signal measurement data.

[0036] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0037] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0038] Figure 1A schematic diagram of a rotating scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement according to an embodiment of the present invention is shown.

[0039] Figure 2 A schematic diagram of the composition of a rotating scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement according to an embodiment of the present invention is shown.

[0040] Figure 3 A schematic diagram of a circuit module according to an embodiment of the present invention is shown;

[0041] Figure 4 A flowchart illustrating the steps of a rotary scanning logging method for measuring downhole multimode ultrasonic guided wave signals according to an embodiment of the present invention is shown.

[0042] In the accompanying drawings, the same parts use the same reference numerals. Also, the drawings are not drawn to scale.

[0043] The meanings of the reference numerals in the attached figures are as follows: 1-Bearing frame; 11-Bearing prism; 111-Slot; 112-Cavity; 113-Oil plug; 114-Balance piston; 12-Upper electrical connector; 121-Multi-core pressure-bearing connector; 13-Lower protective connector; 131-Elastic rubber; 2-Circuit module; 21-Control circuit; 22-Excitation circuit; 23-Acquisition circuit; 24-Data buffer circuit; 25-Power conversion circuit; 26-Pressure-bearing sealed electrical interface; 27-Multi-core connector; 28-Metal housing; 29-Organic silicone; 3-Ultrasonic transducer assembly; 31-Transmitter / receiver ultrasonic transducer; 32-Transmitting ultrasonic transducer; 33-First receiving ultrasonic transducer; 34-Second receiving ultrasonic transducer; 35-Third receiving ultrasonic transducer; 36-Sealing ring; 37-Elastic retaining ring; 4-High-temperature wire; 5-Transmission bus; 6-Multi-core wire. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0045] Prior art (US6474439B1) provides a logging tool having a tool body that can be positioned in a fluid-filled borehole, including a receiver section and a dipole transmitter; wherein the dipole transmitter includes a transducer with a housing having a reaction mass and an electric motor located therein, the electric motor being operatively connected to the housing and the reaction mass such that only the outer surface of the housing contacts the fluid in the borehole. However, in the above-mentioned prior art, the transmitter section 110, the receiver section 130, and the power electronics 111 are separate short sections, which requires the use of long-distance (greater than 2.5m) through-wires for electrical connections. This inevitably introduces strong noise interference into the measurement of ultrasonic mode wave signals in the frequency range of 200-700kHz and crosstalk between multi-channel analog signal transmissions, thereby significantly reducing the signal-to-noise ratio of the logging data.

[0046] Prior art (US20220365240A1) provides a method for identifying material behind a tubing string. This method may include deploying an acoustic logging tool into the wellbore, using the acoustic logging tool to perform acoustic processing on the tubing string within the wellbore, and recording acoustic or ultrasonic data. The method may also include inputting the acoustic or ultrasonic data into a trained machine learning model and using the trained machine learning model to identify the material behind the tubing string. However, in the aforementioned prior art, the tool 100 includes four ultrasonic transducers, of which one self-transmitting and self-receiving ultrasonic transducer 304 is vertically placed on one side of the instrument, and the other three ultrasonic transducers (one transmitter 102, and two receivers 300, 302) are arranged at a certain tilt angle on the other side of the instrument, forming a one-transmitter, two-receiver logging acoustic system. Due to the uneven distribution of the ultrasonic transducers on both sides and the requirement for a certain source distance, the center of gravity of the rotating scanning logging acoustic system deviates from the rotation axis. During high-speed scanning logging, lateral vibration easily occurs, resulting in non-uniform eccentric rotation, which seriously affects the quality of logging data and the logging success rate.

[0047] The prior art (CN216110689U) relates to an imaging logging tool, comprising: an acoustic sub and a motor sub; the output shaft of the motor sub is fixedly connected to the acoustic sub; the acoustic sub is provided with a self-generating and self-receiving transducer, an inclined transmitting transducer, and an inclined receiving transducer; the self-generating and self-receiving transducer is vertically mounted on the acoustic sub, and the inclined transmitting transducer and the inclined receiving transducer are both inclinedly mounted on the acoustic sub; the inclined receiving transducer and the inclined transmitting transducer are located on the same side of the acoustic sub.

[0048] However, in the existing technology (CN216110689U), the acoustic section 100 and the circuit section 500 are two independent sections, separated by a centralizer 9 (first centralizer 300, second centralizer 400) and a rotary actuator (motor 200). This requires the use of long-distance (greater than 2.5m) through-wires for the electrical connection between the circuit section 500 and the acoustic section 100. This inevitably introduces strong noise interference into the measurement of ultrasonic mode wave signals in the frequency range of 200-700kHz and crosstalk between multi-channel analog signal transmissions, thus significantly reducing the signal-to-noise ratio of the logging data.

[0049] Furthermore, in the existing technology (CN216110689U), the acoustic system subsection 100 includes four ultrasonic transducers. One self-transmitting and self-receiving ultrasonic transducer 110 is placed vertically on one side of the instrument, while the other three ultrasonic transducers (one transmitter 120 and two receivers 130) are arranged at a certain tilt angle on the other side of the instrument, forming a one-transmitter, two-receiver logging acoustic system. Due to the uneven distribution of the ultrasonic transducers on both sides and the requirement for a certain source distance, the center of gravity of the rotary scanning logging acoustic system deviates from the rotation axis. During high-speed scanning logging, lateral vibration easily occurs, resulting in non-uniform eccentric rotation, which seriously affects the quality of logging data and the logging success rate.

[0050] Therefore, in the design of rotary scanning logging acoustic systems, the problem of center of gravity deviation is often solved by adding counterweights or pressure balancing structures (either inside the transducer or outside the acoustic system). However, this design of adding counterweights or pressure balancing structures not only occupies space in the rotary scanning logging acoustic system but also makes it difficult to lay long-distance through-wires.

[0051] The prior art (CN109281652A) relates to a wellbore imaging system based on a cylindrical ultrasonic phased array, comprising: a ground controller, a power supply section, an acoustic section, and a circuit section; the power supply section is used to power the system; the acoustic section includes a cylindrical ultrasonic phased array probe, which consists of several transducer elements arranged circumferentially in a cylindrical shape; the circuit section is used to control each transducer element in the cylindrical ultrasonic phased array probe to focus and transmit ultrasonic signals and receive echo signals circumferentially according to the control signal sent by the ground controller, and to send the acquired echo data to the ground controller; the ground controller is used to perform imaging based on the received echo data. However, in the above-mentioned prior art, the acoustic section 4 and the circuit section 3 are two independent sections, and a pressure balancing mechanism 12 is set inside the acoustic section 4. This design not only occupies the space of the rotary scanning logging acoustic system, but also makes it difficult to lay long-distance through-wires.

[0052] To address the aforementioned deficiencies of existing technologies, this invention overcomes the shortcomings of existing rotary scanning logging acoustic systems in casing well logging, such as non-uniform rotation caused by the deviation of the center of gravity, limited wiring space, and strong noise interference introduced by a large number of long-distance wiring. It provides a rotary scanning logging acoustic system for measuring multimode ultrasonic guided wave signals in downhole wells, enabling high-speed uniform rotation in a confined space under high temperature and pressure while simultaneously stimulating multiple transmitters synchronously and acquiring data from multiple receivers in parallel at close range. This also enables the measurement of various ultrasonic guided wave signals, such as S1 guided wave and A0 guided wave, in downhole casing.

[0053] Figure 1 A schematic diagram of a rotating scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement according to an embodiment of the present invention is shown.

[0054] The rotating scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement includes: a support frame 1, a circuit module 2, an ultrasonic transducer assembly 3, and a transmission bus 5. The support frame 1 is used to dynamically adjust the center of gravity of the acoustic system; the circuit module 2 is mounted on the support frame 1; the ultrasonic transducer assembly 3 is mounted on the support frame 1 and connected to the circuit module 2; the transmission bus 5 supports interconnection and communication between the circuit modules 2.

[0055] like Figure 1 As shown, the supporting frame 1 includes: a supporting prism 11, an upper electrical connector 12, and a lower protective connector 13. The supporting prism 11 is used to house the circuit module 2 and the ultrasonic transducer assembly 3, and also for dynamically adjusting the center of gravity of the acoustic system; the upper electrical connector 12 is located at one end of the supporting prism 11 for electrical connection; the lower protective connector 13 is located at the other end of the supporting prism 11 for protecting the supporting frame 1.

[0056] In one embodiment, such as Figure 1 As shown, the supporting prism 11 includes slots 111 for mounting the ultrasonic transducer assembly 3 and cavities 112 for mounting the circuit module 2. The circuit module 2 and the ultrasonic transducer assembly 3 are connected by high-temperature wires 4. Specifically, the rotary scanning logging acoustic system of the present invention uses the supporting frame 1 as a carrier, and integrates the circuit module (excitation acquisition circuit assembly) 2 and two or more ultrasonic transducers (e.g., 31-35) inside. The circuit module 2 and the two or more ultrasonic transducers (e.g., 31-35) are electrically connected nearby by close-range high-temperature wires 4.

[0057] In one embodiment, such as Figure 1 As shown, the internal cavity of the supporting prism 11 is filled with hydraulic oil. A balance piston 114 is provided at the inlet and outlet ends of the internal cavity to dynamically adjust the center of gravity of the sound system. An oil plug 113 is also provided at the inlet end of the internal cavity.

[0058] In summary, the support frame 1 consists of a support prism 11, an upper (quick-turn) electrical connector 12, and a lower protective connector 13. The support prism 11 has multiple interconnected slots 111 and cavities 112 for embedding and installing circuit modules 2 and two or more ultrasonic transducers (e.g., 31-35). The internal cavities of the support prism 11 are filled with hydraulic oil to achieve hydraulic dynamic balance and counteract the pressure of the external drilling fluid. The multiple interconnected slots 111 and cavities 112 are also isolated from the external drilling fluid by oil plugs 113 and two balance pistons 114. The embedding depth of the two balance pistons 114 can be adjusted to increase or decrease the hydraulic oil volume, dynamically adjusting the center of gravity of the rotary scanning logging acoustic system. The upper (quick-turn) electrical connector 12 integrates a multi-core pressure-bearing connector 121 for quick helical engagement with the rotary actuator and for electrical connection between the two. The lower protective connector 13 is coated with elastic rubber 131 on the outside to protect the load-bearing frame 1 from contact with the bottom of the well and damage to the circuit module 2 and two or more ultrasonic transducers (e.g., 31-35).

[0059] In one embodiment, such as Figure 1 As shown, the ultrasonic transducer group 3 includes: a transceiver ultrasonic transducer 31, a transmitting ultrasonic transducer 32, and at least two receiving ultrasonic transducers (e.g., 33, 34, 35), wherein: the transceiver ultrasonic transducer 31 is used for self-transmitting and receiving ultrasonic pulse reflected echoes and S1 guided wave signals vertically; the transmitting ultrasonic transducer 32 and at least two receiving ultrasonic transducers (e.g., 33, 34, 35) form a one-transmitter-multiple-receiver logging mode, used for inclined transmission and reception of ultrasonic pulse A0 guided wave signals and subsequent reflected waves.

[0060] In one embodiment, each ultrasonic transducer in the ultrasonic transducer group 3 has a sealing ring 36 nested on its outer surface and directly inserted into the corresponding slot 111. Each ultrasonic transducer is fitted with an elastic retaining ring 37 on its outer side to restrict its movement to the external drilling fluid. Each ultrasonic transducer is connected to the multi-core connector 27 of the circuit module 2 via a high-temperature wire 4.

[0061] In summary, in one embodiment, the ultrasonic transducer 3 consists of one transceiver ultrasonic transducer 31, one ultrasonic transmitter 32, and three ultrasonic receivers 33, 34, and 35. The transceiver ultrasonic transducer 31 is used for self-transmitting and receiving ultrasonic pulse reflected echoes and S1 guided wave signals vertically. The ultrasonic transmitter 32 and the three ultrasonic receivers 33, 34, and 35 form a one-transmitter-three-receiver logging acoustic system, used for transmitting and receiving ultrasonic pulse A0 guided wave signals and subsequent reflected waves at a certain tilt angle. All ultrasonic transducers 31-35 have sealing rings 36 nested on their outer surfaces, directly inserted into slots 111 inside the supporting prism body, and elastic retaining rings 37 on the outside to restrict their movement to the external drilling fluid. A multi-core connector 27 is used for close-range connection with the circuit module 2.

[0062] like Figure 1 As shown, circuit module 2 is interconnected with the main control electronic compartment via transmission bus 5. Simultaneously, the main control electronic compartment also transmits electrical energy to circuit module 2 via multi-core wire 6. Specifically, the rotary scanning logging acoustic system is interconnected with the main control electronic compartment via high-speed serial data transmission bus 5. Furthermore, the main control electronic compartment also transmits electrical energy to the rotary scanning logging acoustic system via multi-core wire 6 to power circuit module 2.

[0063] like Figure 1 As shown, this invention provides a rotating scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement, specifically including a support frame 1, a circuit module 2, and an ultrasonic transducer group 3 composed of multiple ultrasonic transducers. The circuit module 2 and the ultrasonic transducer group 3 are integrated inside the support frame 1, and they are electrically connected at close range via high-temperature wires 4. They are also interconnected with the main control electronic compartment via a high-speed serial data transmission bus 5 and a power transmission line 6. The rotating scanning logging acoustic system of this invention also employs hydraulic dynamic balancing and adjustments to the hydraulic oil volume to adjust the center of gravity of the acoustic system, enabling it to achieve high-speed, uniform rotation downhole. This invention is applied to the development of ultrasonic guided wave imaging logging instruments, breaking through key technologies such as high-speed uniform rotation with close-range synchronous excitation and parallel acquisition, and long-distance serial data transmission. It overcomes the defects of non-uniform rotation due to center of gravity deviation and the simulation of signal transmission with numerous long-distance through-wires, improving the signal-to-noise ratio of ultrasonic guided wave imaging logging data acquisition and the quality of imaging processing.

[0064] Figure 2 A schematic diagram of the composition of a rotating scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement according to an embodiment of the present invention is shown.

[0065] like Figure 2As shown, the rotary scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement consists of a support frame 1, circuit modules 2, ultrasonic transducer assembly 3, high-temperature conductors 4, data transmission bus 5, and multi-core conductors 6. The circuit modules 2 and ultrasonic transducer assembly 3 are installed and fixed inside the support frame 1, and they are electrically connected nearby using the high-temperature conductors 4. The rotary scanning logging acoustic system communicates with the main control electronics unit via the high-speed serial data transmission bus 5. Simultaneously, the main control electronics unit also supplies power to the rotary scanning logging acoustic system to power the excitation acquisition circuit assembly 2 via the multi-core conductors 6.

[0066] In one embodiment, such as Figure 2 As shown, the excitation and acquisition circuit for downhole multimode ultrasonic guided wave signal measurement of the present invention is encapsulated in circuit module 2, specifically including: control circuit 21, excitation circuit 22, acquisition circuit 23, data buffer circuit 24, power conversion circuit 25, and pressure-bearing sealed electrical interface 26.

[0067] The control circuit 21 controls the excitation circuit 21, the acquisition circuit 23, the data buffer circuit 24, and the power conversion circuit 25. Specifically, the control circuit 21 uses an FPGA (Field-programmable Gate Array) device as its control core. It receives operating commands, decodes and generates operating timing sequences, sets excitation parameters, programmable gain, and acquisition parameters, and controls the storage and transmission of ultrasonic guided wave signal data (S0, A0). It also communicates with the main control electronic compartment via the high-speed serial data transmission bus 5. Furthermore, the control circuit 21 receives operating commands from the main control electronic compartment, sends acquisition data to the main control electronic compartment, and decodes and sets the operating parameters and operating timing sequences of the excitation circuit 22 and the acquisition circuit 23.

[0068] The excitation circuit 22 is used to generate high-voltage pulses to synchronously excite the transceiver ultrasonic transducer 31 and the transmitting ultrasonic transducer 32. Specifically, the excitation circuit 22 is used to generate high-voltage pulses to synchronously excite at least two transmitters to radiate ultrasonic signals in opposite directions.

[0069] The acquisition circuit 23 includes at least two independent, fully parallel acquisition channels for digitally and in parallel acquiring ultrasonic guided wave signals received by at least two receiving ultrasonic transducers (e.g., 33, 34, 35). Specifically, the acquisition circuit 23 is used for digitally and in parallel acquiring ultrasonic guided wave signals received by multiple receivers. Further, the acquisition circuit 23 is used for amplifying, filtering, and digitally and in parallel acquiring ultrasonic guided wave signals received by at least three receivers (e.g., 33, 34, 35).

[0070] The data buffer circuit 24 is used to store the digitized ultrasonic guided wave signals output by the acquisition circuit 23. Specifically, the data buffer circuit 24 is used to store the digitized ultrasonic guided wave signals recorded by the acquisition channels. Furthermore, the data buffer circuit 24 is used to store ultrasonic guided wave signals digitized from at least three channels, with a storage capacity of 256MB.

[0071] The power conversion circuit 25 is used to supply power to the circuit module 2. Specifically, the power conversion circuit 25 is used to output the power supply operating voltage to supply power to the circuit module 2. Further, the power conversion circuit 25 is used to output various power supply operating voltages such as high voltage (400V) and low voltage (3.3V, 1.2V, 1.8V, ±5V) to supply power to the various devices in the circuit module 2.

[0072] The pressure-sealed electrical interface 26 is used to connect the circuit module 2 and the main control electronic compartment, enabling synchronous excitation and parallel acquisition of ultrasonic guided wave signals, serial data transmission bus communication, and DC voltage power supply. The multi-core connector 27 is used to connect the circuit module 2 and the ultrasonic transducer assembly 3. Specifically, the pressure-sealed electrical interface 26 is used to seal the circuit module 2 and connect to the main control electronic compartment to achieve serial data transmission bus communication and DC voltage power delivery.

[0073] Combination Figure 1 As shown, the circuit module 2 for downhole multimode ultrasonic guided wave signal measurement of the present invention is integrated on the supporting frame 1 of the rotating scanning logging acoustic system, and is closely connected to the ultrasonic transducer group 3, and is interconnected with the main control system of the main control electronic compartment through the high-speed serial data transmission bus 5.

[0074] The rotary scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement of this invention is used to connect the ultrasonic imaging logging system in casing wells with the main control electronic compartment, realizing the synchronous excitation and parallel acquisition, data storage, and high-speed transmission of multiple ultrasonic guided wave signals. The rotary scanning logging acoustic system uses hydraulic dynamic balancing to offset external drilling fluid pressure and adjusts the system's center of gravity by increasing or decreasing the hydraulic oil volume. Directly exposed in the downhole drilling fluid medium, it can perform ultrasonic guided wave scanning measurements while rotating at high speed and uniformly under high temperature (175℃), high pressure (140MPa), and confined space (casing size 5.0–8.5in). The rotary scanning logging acoustic system has an outer diameter of 85–92 mm, a length of 500–600 mm, a source distance of 20–25 mm for one transmitter and three receivers, and a spacing of 50–100 mm. The frequency of the ultrasonic guided wave signal measured by the rotary scanning logging acoustic system is 200–350 kHz.

[0075] The rotary scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement of this invention has the circuit module 2 pre-installed and fixed inside the rotary scanning logging acoustic system and electrically connected nearby to the ultrasonic transducer group 3, shortening the length of the ultrasonic guided wave signal transmission, reception, and acquisition transmission line and reducing noise interference in guided wave signal measurement. Simultaneously, the rotary scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement of this invention also dynamically adjusts the center of gravity of the rotary scanning logging acoustic system by increasing or decreasing the amount of hydraulic oil, ensuring that its center of gravity remains on the rotation axis during high-speed rotation, achieving high-speed uniform rotation under downhole high-temperature and high-pressure conditions. Therefore, the rotary scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement of this invention can simultaneously excite multiple transmitters synchronously and acquire data in parallel from multiple receivers at close range while rotating at high speed and uniformly in the confined space under high-temperature and high-pressure conditions, realizing the measurement of various ultrasonic guided wave signals such as S1 guided wave and A0 guided wave in the downhole casing. Furthermore, long-distance, high-speed, efficient, and reliable data communication is achieved with the main control electronic compartment through the high-speed serial data transmission bus 5.

[0076] Figure 3 A schematic diagram of a circuit module according to an embodiment of the present invention is shown.

[0077] like Figure 3 As shown, circuit module 2 is rectangular in shape, surrounded by a metal shell 28, and completely filled with silicone 29 to enhance vibration resistance (circuit module 2 is encapsulated in silicone 29 to form a rectangular structure, which is embedded and fixed in the cavity 112 inside the supporting prism 11). At least two multi-core connectors 27 are provided at both ends of circuit module 2. Circuit module 2 is embedded and fixed in the cavity 112 of the supporting frame 1, and uses multiple single-core pressure-sealed pins to form a pressure-sealed electrical interface 26. The pressure-sealed electrical interface 26 is fixed and sealed to the end of the cavity 112 of the supporting frame 1 by positioning pins and sealing rings, and is used for serial data transmission bus interface and power supply voltage transmission. Its inner side connects to circuit module 2, and its outer side connects to the main control electronic compartment.

[0078] Circuit module 2 includes at least two excitation circuits 22, each consisting of a high-voltage energy storage circuit, a low-voltage drive circuit, and a high-power switching circuit. The excitation circuits 22 operate under the excitation control signal triggered by the control circuit 21, generating high-voltage pulses to synchronously excite at least two transmitters to radiate ultrasonic signals in opposite directions. The technical specifications of the excitation circuits are: high-voltage pulse amplitude 400V, pulse width adjustable from 1 to 4μs, and transmission cycle 5ms.

[0079] Circuit module 2 contains at least three independent, fully parallel acquisition channels, and all three channels are simultaneously activated via broadcast. Each channel's acquisition circuit 23 consists of a multi-channel selection circuit, a preamplifier circuit, an active bandpass filter, an automatic gain control circuit, and an analog-to-digital converter circuit. Acquisition circuit 23 operates under the acquisition control signal triggered by control circuit 21, performing digital parallel acquisition of ultrasonic guided wave signals received by at least three receivers. The acquisition circuit's specifications are: at least three channels, 16-bit sampling accuracy, 5MHz sampling frequency, and a gain range of -14 to 66dB.

[0080] The rotary scanning logging acoustic system of the present invention for downhole multimode ultrasonic guided wave signal measurement, operating under the high temperature, high pressure, and confined space conditions of downhole, utilizes a circuit module 2 mounted on the supporting frame 1 of the rotary scanning acoustic system. This allows for short high-temperature wires 4 to be led out from within the acoustic system, enabling close-range electrical connections between at least two transmitters (e.g., 31, 32) and at least three receivers (e.g., 33, 34, 35) and the circuit module 2. This reduces the need for multiple multi-core connectors that are difficult to shield, thus improving the signal-to-noise ratio of ultrasonic guided wave signal data acquisition and the quality of imaging processing. The circuit module 2 located on the supporting frame of the rotary scanning acoustic system and the main control system in the main control electronics compartment are interconnected via a serial data transmission bus 5. Long-distance digital signal transmission ensures optimal signal-to-noise ratio for the measurement data.

[0081] The rotary scanning logging acoustic system of the present invention for downhole multimode ultrasonic guided wave signal measurement integrates multiple ultrasonic transducers, realizing the generation of A0 mode wave signal by oblique incidence of at least one transmitting and two receiving logging acoustic system and the generation of S1 mode wave signal by vertical incidence of self-transmitting and self-receiving acoustic system.

[0082] Therefore, the rotary scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement of the present invention has made breakthroughs in key technologies such as high-speed uniform rotation with close-range synchronous excitation and parallel acquisition, and long-distance serial data transmission. It overcomes the defects of non-uniform rotation with center of gravity deviation and long-distance large number of through-wires to simulate signal transmission, and improves the signal-to-noise ratio of ultrasonic guided wave imaging logging data acquisition and the quality of imaging processing.

[0083] In summary, to overcome the shortcomings of existing technologies, such as the lack of high-speed uniform rotation and close-range excitation acquisition for multimode ultrasonic guided wave signal measurement in casing wells, this invention provides a rotary scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement. By combining the rotary scanning logging acoustic system of this invention with the main control electronic compartment sub, directional measurement sub, roller centralizer, etc., multimode ultrasonic guided wave imaging logging in casing wells can be performed, enabling the detection and evaluation of cement bonding quality and casing damage.

[0084] Therefore, the rotary scanning logging acoustic system of the present invention is an improvement and innovation of existing ultrasonic imaging logging technology.

[0085] First, the circuit module 2 is directly installed on the supporting frame 1 of the rotary scanning logging acoustic system, forming an independent circuit module 2 with good sealing and insulation. It is electrically connected to at least two transmitters (31, 32) and at least three receivers (33, 34, 35) in the acoustic system with a small number of high-temperature wires 4, which solves the problem of large noise interference in long-distance analog signal transmission.

[0086] Second, the circuit module 2 located on the acoustic system support frame 1 is interconnected with the main control system of the main control electronic compartment through the high-speed serial data transmission bus 5, realizing long-distance high signal-to-noise ratio and high reliability data transmission.

[0087] Third, by increasing or decreasing the amount of hydraulic oil, the center of gravity of the acoustic system is dynamically adjusted so that it remains on the axis of rotation throughout the logging process, enabling high-speed and uniform rotational scanning measurement of the instrument under high temperature and high pressure conditions downhole.

[0088] Figure 4 A flowchart illustrating the steps of a rotary scanning logging method for measuring downhole multimode ultrasonic guided wave signals according to an embodiment of the present invention is shown.

[0089] According to another aspect of the present invention, a rotary scanning logging method for measuring downhole multimode ultrasonic guided wave signals is also provided, which is executed by a rotary scanning logging acoustic system for measuring downhole multimode ultrasonic guided wave signals.

[0090] like Figure 4 As shown, in step S1, an ultrasonic signal is emitted, wherein the ultrasonic signal includes a vertical ultrasonic signal and an inclined ultrasonic signal. The emission direction of the vertical ultrasonic signal is perpendicular to the axis of the acoustic system, and the emission direction of the inclined ultrasonic signal has a preset tilt angle with the axis of the acoustic system.

[0091] like Figure 4 As shown, in step S2, a feedback signal is received, wherein the feedback signal includes the A0 guided wave signal and the S1 guided wave signal.

[0092] The rotary scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement provided by this invention can also be used in conjunction with a computer-readable storage medium. The storage medium stores a computer program, which is executed to run a rotary scanning logging method for downhole multimode ultrasonic guided wave signal measurement. The computer program can execute computer instructions, which include computer program code. The computer program code can be in the form of source code, object code, executable file, or some intermediate form.

[0093] Computer-readable storage media can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0094] It should be noted that the contents of computer-readable storage media may be appropriately added to or subtracted from the contents according to the requirements of legislation and patent practice in a jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable storage media may not include electrical carrier signals and telecommunication signals.

[0095] In summary, this invention provides a rotary scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement. Compared with existing technologies, it has the following advantages: Addressing the shortcomings of existing rotary scanning logging acoustic systems for casing well logging, such as non-uniform rotation due to center-of-gravity deviation, limited wiring space, and strong noise interference introduced by long-distance wiring, this invention provides a rotary scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement. When applied to the development of ultrasonic scanning imaging logging instruments, it exhibits significant advantages in uniform high-speed rotation measurement, close-range electrical connections, and noise reduction, thereby improving the signal-to-noise ratio and logging success rate of downhole multimode ultrasonic guided wave signal measurement data.

[0096] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should be extended to equivalent substitutions of these features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0097] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0098] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0099] Certain terms are used throughout this application to refer to specific system components. As those skilled in the art will recognize, the same components may often be referred to by different names, and therefore this application is not intended to distinguish those components that differ only in name and not in function. In this application, the terms “comprise,” “include,” and “have” are used in an open-ended manner and should therefore be interpreted as meaning “including, but not limited to…”. Furthermore, the terms “substantially,” “materially,” or “approximately” as used herein refer to industry-accepted tolerances for the corresponding terms. The term “coupling,” as may be used herein, includes direct coupling and indirect coupling via additional components, elements, circuits, or modules, wherein, for indirect coupling, the intermediate component, element, circuit, or module does not alter the information of the signal but may adjust its current level, voltage level, and / or power level. Inferred coupling (e.g., one element is inferredly coupled to another element) includes direct and indirect coupling between two elements in the same manner as “coupling.”

[0100] The phrase "an embodiment" or "an embodiment" used in this specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Therefore, the phrase "an embodiment" or "an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0101] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

[0102] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and variations in form and detail of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A rotating scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement, characterized in that, The acoustic system includes: A supporting frame, which is used to dynamically adjust the center of gravity of the acoustic system; The circuit module is disposed on the supporting frame; An ultrasonic transducer assembly is mounted on the supporting frame and connected to the circuit module; A transmission bus is used to support interconnection and communication between the circuit modules.

2. The rotating scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement as described in claim 1, characterized in that, The load-bearing frame includes: The supporting prism is used to house the circuit module and the ultrasonic transducer assembly, and also to dynamically adjust the center of gravity of the acoustic system. An upper electrical connector is located at one end of the supporting prism and is used to achieve electrical connection; The lower end protective joint is located at the other end of the load-bearing prism and is used to protect the load-bearing frame.

3. The rotating scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement as described in claim 2, characterized in that, The supporting prism includes slots for housing the ultrasonic transducer assembly and cavities for housing the circuit module. The circuit module is connected to the ultrasonic transducer assembly via high-temperature wires.

4. A rotating scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement as described in claim 2 or 3, characterized in that, The internal cavity of the supporting prism is filled with hydraulic oil. A balance piston is provided at the inlet and outlet ends of the internal cavity to dynamically adjust the center of gravity of the acoustic system. An oil injection plug is also provided at the inlet end of the internal cavity.

5. A rotating scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement as described in claim 3 or 4, characterized in that, Each ultrasonic transducer in the ultrasonic transducer group has a sealing ring nested on its outer surface and is directly inserted into the corresponding slot. Each ultrasonic transducer is also equipped with an elastic retaining ring on its outer side to restrict its movement to the external drilling fluid. Each ultrasonic transducer is connected to the multi-core connector of the circuit module through the high-temperature wire.

6. A rotating scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement as described in any one of claims 1-5, characterized in that, The ultrasonic transducer assembly comprises: one transceiver ultrasonic transducer, one transmitting ultrasonic transducer, and at least two receiving ultrasonic transducers, wherein: The transceiver ultrasonic transducer is used for self-transmitting and receiving ultrasonic pulse reflection echoes and S1 guided wave signals in a vertical manner. One of the transmitting ultrasonic transducers and at least two of the receiving ultrasonic transducers constitute a one-to-many logging mode for inclined transmission and reception of ultrasonic pulse A0 guided wave signals and subsequent reflected waves.

7. The rotating scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement as described in claim 6, characterized in that, The circuit module includes: An excitation circuit is used to generate high-voltage pulses to synchronously excite the transceiver ultrasonic transducer and the transmitting ultrasonic transducer. The acquisition circuit includes at least two independent, fully parallel acquisition channels for digitally acquiring ultrasonic guided wave signals received by at least two of the receiving ultrasonic transducers in parallel. A data buffer circuit is used to store the digitized ultrasonic guided wave signal output by the acquisition circuit; A power conversion circuit is used to supply power to the circuit module; A control circuit is used to control the excitation circuit, the acquisition circuit, the data buffer circuit, and the power conversion circuit.

8. A rotating scanning logging acoustic system for downhole multimode ultrasonic guided wave signal measurement as described in any one of claims 1-7, characterized in that, The circuit module communicates with the main control electronic compartment via the transmission bus. Meanwhile, the main control electronic compartment also transmits electrical energy to the circuit module via multi-core wires.

9. A rotating scanning logging method for measuring downhole multimode ultrasonic guided wave signals, characterized in that, Performed via the acoustic system as described in any one of claims 1-8, the method comprises: The ultrasonic signal is emitted, wherein the ultrasonic signal includes a vertical ultrasonic signal and an inclined ultrasonic signal, the emission direction of the vertical ultrasonic signal is perpendicular to the axis of the acoustic system, and the emission direction of the inclined ultrasonic signal has a preset tilt angle with the axis of the acoustic system. Receive feedback signals, wherein the feedback signals include A0 guided wave signals and S1 guided wave signals.

10. A storage medium, characterized in that, It contains instructions for performing the method as described in claim 9.

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