Multi-pole sound wave receiving unit and multi-pole sound wave receiving device

Abstract

The multi-pole sound wave receiving unit and the multi-pole sound wave receiving device are applied to the technical field of petroleum well logging, the multi-pole sound wave receiving unit comprises a framework, and the peripheral part of the framework comprises a first peripheral part and a second peripheral part which are distributed in the axis direction; the first peripheral part is provided with a plurality of receiving transducer assemblies which are uniformly distributed along the circumferential direction, and the second peripheral part is provided with a plurality of receiving pre-amplification circuit board assemblies which are distributed along the circumferential direction; and the receiving transducer assembly is electrically connected with the adjacent receiving pre-amplifier circuit board assembly along the axis direction through a first transmission line. The pre-amplification circuit board assembly is arranged at the position close to the receiving transducer assembly and is electrically connected with the receiving transducer assembly, so that an electric signal acquired by the receiving transducer assembly can be transmitted to the pre-amplification circuit board assembly for signal filtering optimization and amplification enhancement only through a short distance, and the signal quality and the anti-interference performance can be effectively improved; therefore, the multi-pole sound wave receiving unit has a high signal-to-noise ratio.

Description

Technical Field

[0001] This invention relates to the field of oil well logging technology, and in particular to a multipole acoustic wave receiving unit and a multipole acoustic wave receiving device. Background Technology

[0002] At present, multipole acoustic wave receivers mostly use individual sheet piezoelectric receiving transducers. A receiving unit is formed by arranging receiving transducers with sheet piezoelectric ceramics in multiple directions. Each receiving transducer consists of two sheet piezoelectric ceramics connected in parallel to receive acoustic wave signals. This forms a multipole receiver unit responsible for converting acoustic wave signals into weak electrical signals.

[0003] Then, these weak electrical signals are sent via cable to an isolated line in the instrument circuit unit located at a distance for amplification and filtering. Due to the weak signal during signal transmission, this receiving method is susceptible to strong electromagnetic interference from external sources and the sound source during transmission. When receiving acoustic signals from softer and looser formations such as sponges, the receiving unit will have problems such as low signal-to-noise ratio and large baseline interference, making it impossible to complete multipole acoustic logging normally.

[0004] Therefore, how to provide a multipole acoustic wave receiving unit with a high signal-to-noise ratio is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a multipole acoustic wave receiving unit with a high signal-to-noise ratio; another purpose of this invention is to provide a multipole acoustic wave receiving device with a high signal-to-noise ratio.

[0006] To solve the above-mentioned technical problems, the present invention provides a multipole acoustic wave receiving unit, including a frame, wherein the outer periphery of the frame includes a first outer periphery and a second outer periphery distributed along the axial direction;

[0007] The first outer periphery is provided with a plurality of receiving transducer assemblies evenly distributed along the circumferential direction, and the second outer periphery is provided with a plurality of receiving preamplifier circuit board assemblies distributed along the circumferential direction.

[0008] The receiving transducer assembly is electrically connected to the receiving preamplifier circuit board assembly adjacent along the axial direction via a first transmission line.

[0009] Optionally, the frame includes a frame body and a sound insulation block that are fixedly connected, and the frame body and the sound insulation block are arranged sequentially along the axial direction;

[0010] The main frame has a first outer periphery and is provided with the receiving transducer assembly; the sound insulation block has a second outer periphery and is provided with the receiving preamplifier circuit board assembly.

[0011] Optionally, the first outer periphery is uniformly provided with a plurality of receiving transducer grooves along the circumferential direction, and the receiving transducer assembly is fixed in the corresponding receiving transducer groove.

[0012] The receiving transducer groove is provided with a first notch facing the baffle of the sound insulation block to form a receiving cable groove based on the first notch; the first transmission line connects the receiving transducer assembly and the receiving preamplifier circuit board assembly through the receiving cable groove.

[0013] Optionally, the connection between the frame body and the sound insulation block is formed with a spaced groove extending along the circumferential direction, and the spaced groove communicates with the receiving groove.

[0014] Optionally, a wiring groove is formed between adjacent receiving transducer recesses.

[0015] Optional, cable ties are also included;

[0016] The receiving transducer groove is provided with a second notch facing the baffle wall of the adjacent receiving transducer groove, so as to form a cable tie groove extending in the circumferential direction based on the second notch, and the cable tie is disposed in the cable tie groove.

[0017] Optionally, the receiving transducer assembly is fixed to the first outer periphery by a pad, the pad being at least partially located between the receiving transducer assembly and the first outer periphery;

[0018] And / or, the receiving preamplifier circuit board assembly is fixed to the second outer periphery by a clamping block.

[0019] Optionally, the receiving transducer assembly includes two stacked piezoelectric ceramic sheets, which are polarized along the thickness direction;

[0020] The positive electrode side surface of one of the piezoelectric ceramic sheets is in contact with and electrically connected to the negative electrode side surface of the other piezoelectric ceramic sheet, so that the two piezoelectric ceramic sheets are connected in series.

[0021] The present invention also provides a multipole acoustic wave receiving device, comprising a plurality of multipole acoustic wave receiving units as described in any of the above claims.

[0022] Optionally, the skeleton includes a through hole extending through the skeleton along the axial direction, and a fixing cable is disposed in the through hole;

[0023] Multiple multipole acoustic wave receiving units are distributed along the axial direction and are connected by the fixed cable.

[0024] The present invention provides a multipole acoustic wave receiving unit, comprising a frame, the outer periphery of which includes a first outer periphery and a second outer periphery distributed along the axial direction; the first outer periphery is provided with a plurality of receiving transducer assemblies uniformly distributed along the circumferential direction, and the second outer periphery is provided with a plurality of receiving preamplifier circuit board assemblies distributed along the circumferential direction; the receiving transducer assemblies and the receiving preamplifier circuit board assemblies adjacent along the axial direction are electrically connected through a first transmission line.

[0025] By placing a preamplifier circuit board assembly near the receiving transducer assembly on the frame and electrically connecting the adjacent receiving transducer assembly to the preamplifier circuit board assembly, the electrical signal collected by the receiving transducer assembly can be transmitted to the preamplifier circuit board assembly for signal filtering optimization and amplification enhancement over a very short distance. This can effectively improve signal quality and anti-interference performance, giving the multipole acoustic wave receiving unit a high signal-to-noise ratio.

[0026] The present invention also provides a multipole acoustic wave receiving device, which has the same beneficial effects as described above, and will not be described in detail here. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the structure of a multipole acoustic wave receiving unit provided in an embodiment of the present invention;

[0029] Figure 2 for Figure 1 Schematic diagram of the main structure of the central skeleton;

[0030] Figure 3 for Figure 1 Schematic diagram of the sound insulation block structure;

[0031] Figure 4 This is a schematic diagram of the structure of a specific receiving transducer assembly provided in an embodiment of the present invention;

[0032] Figure 5 A comparison graph of the sensitivity of the receiving transducer components;

[0033] Figure 6 This is a schematic diagram of a preamplifier circuit provided in an embodiment of the present invention;

[0034] Figure 7 This is a comparison diagram of acoustic wave reception signals with and without a preamplifier circuit.

[0035] In the diagram: 1. Frame, 2. Receiver transducer assembly, 3. Gasket, 4. Fixing screw hole, 5. Pressure block, 6. Receiver preamplifier circuit board assembly, 7. Pressure block screw hole, 8. Frame body, 9. Through hole, 10. Screw hole, 11. Cable tie groove, 12. Spacing groove, 13. Cable routing groove, 14. Sound insulation block, 15. Receiver cable groove, 16. Through hole;

[0036] 211. Negative electrode conductive sheet; 212. Conductive adhesive; 213. Piezoelectric ceramic sheet; 214. Positive electrode conductive sheet. Detailed Implementation

[0037] The core of this invention is to provide a multipole acoustic wave receiving unit. In the prior art, the receiving transducer is responsible for converting the acoustic wave signal into a weak electrical signal. These weak electrical signals are then sent via cable to an isolated circuit in the instrument circuit unit located at a distance for amplification and filtering. In this receiving method, due to the weak signal during signal transmission, it is susceptible to strong electromagnetic interference from external sources and the sound source during emission. When receiving acoustic wave signals from softer, looser formations such as sponges, this receiving unit suffers from low signal-to-noise ratio and high baseline interference, making it impossible to complete multipole acoustic wave logging normally.

[0038] The multipole acoustic wave receiving unit provided by the present invention includes a frame, the outer periphery of which includes a first outer periphery and a second outer periphery distributed along the axial direction; the first outer periphery is provided with a plurality of receiving transducer assemblies uniformly distributed along the circumferential direction, and the second outer periphery is provided with a plurality of receiving preamplifier circuit board assemblies distributed along the circumferential direction; the receiving transducer assemblies and the receiving preamplifier circuit board assemblies adjacent along the axial direction are electrically connected through a first transmission line.

[0039] By placing a preamplifier circuit board assembly near the receiving transducer assembly on the frame and electrically connecting the adjacent receiving transducer assembly to the preamplifier circuit board assembly, the electrical signal collected by the receiving transducer assembly can be transmitted to the preamplifier circuit board assembly for signal filtering optimization and amplification enhancement over a very short distance. This can effectively improve signal quality and anti-interference performance, giving the multipole acoustic wave receiving unit a high signal-to-noise ratio.

[0040] To enable those skilled in the art to better understand the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Example 1

[0042] Please refer to Figures 1 to 3 , Figure 1 This is a schematic diagram of the structure of a multipole acoustic wave receiving unit provided in an embodiment of the present invention; Figure 2 for Figure 1 Schematic diagram of the main structure of the central skeleton; Figure 3 for Figure 1 A schematic diagram of the structure of the sound insulation block.

[0043] See Figure 1 In this embodiment of the invention, the multipole acoustic wave receiving unit includes a frame 1. The outer periphery of the frame 1 includes a first outer periphery and a second outer periphery distributed along the axial direction. The first outer periphery is provided with a plurality of receiving transducer assemblies 2 evenly distributed along the circumferential direction, and the second outer periphery is provided with a plurality of receiving preamplifier circuit board assemblies 6 distributed along the circumferential direction. The receiving transducer assemblies 2 and the receiving preamplifier circuit board assemblies 6 adjacent along the axial direction are electrically connected through a first transmission line.

[0044] The aforementioned frame 1 is the main supporting structure of the multipole acoustic wave receiving unit. It is typically columnar, thus having three directions: axial, circumferential, and radial. The outer periphery of the frame 1 has a first outer periphery and a second outer periphery along the axial direction. The first outer periphery is used to house the receiving transducer assembly 2, and the second outer periphery is used to house the receiving preamplifier circuit board assembly 6. The specific structures of the receiving transducer assembly 2 and the receiving preamplifier circuit board assembly 6 will be described in detail in the following embodiments of the invention, and will not be repeated here.

[0045] The aforementioned skeleton 1 needs to be a non-magnetic skeleton 1 to ensure the performance of the multipole acoustic wave receiving unit. Specifically, the material of the skeleton body 8 can be non-magnetic stainless steel, that is, the skeleton 1 can be a non-magnetic stainless steel skeleton 1. The skeleton 1 made of this material has a large mass, which can prevent the vibration generated during the reception of acoustic wave signals from causing noise to the receiving transducer assembly 2 when receiving acoustic wave signals, thereby further improving the acoustic wave signal quality of the multipole acoustic wave receiving unit; the non-magnetic material can prevent the electromagnetic signals generated during the acoustic wave transmission process from interfering with the high-precision reception of the receiving transducer assembly 2, thereby improving the quality of the received signal. Of course, in this embodiment, the specific material of the skeleton 1 is not specifically limited, and depends on the specific situation.

[0046] The aforementioned first outer periphery is provided with a plurality of receiving transducer assemblies 2 evenly distributed along the circumferential direction. Typically, four, six, or eight receiving transducer assemblies 2 are evenly distributed along the circumferential direction on the first outer periphery. Specifically, four receiving transducer assemblies 2 can form a four-component receiving transducer assembly 2, which is typically evenly distributed at 90° intervals along the circumference; six receiving transducer assemblies 2 can form a six-component receiving transducer assembly 2, which is typically evenly distributed at 60° intervals along the circumference; and eight receiving transducer assemblies 2 can form an eight-component receiving transducer assembly 2, which is typically evenly distributed at 45° intervals along the circumference. The number of receiving transducer assemblies 2 is not specifically limited in this embodiment and depends on the specific circumstances.

[0047] The aforementioned second outer periphery is provided with a plurality of receiving preamplifier circuit board assemblies 6 distributed along the circumferential direction. These receiving preamplifier circuit board assemblies 6 can be evenly or unevenly distributed along the circumferential direction on the second outer periphery. Typically, it is necessary to ensure that each receiving transducer assembly 2 has an adjacent receiving preamplifier circuit board assembly 6 along the axial direction. Of course, in this embodiment, the receiving transducer assembly 2 and the receiving preamplifier circuit board assembly 6 are usually arranged in a one-to-one correspondence, and the receiving preamplifier circuit board assemblies 6 are also evenly distributed along the circumferential direction on the second outer periphery. Furthermore, each receiving transducer assembly 2 has an adjacent receiving preamplifier circuit board assembly 6 along the axial direction that can be electrically connected.

[0048] In this embodiment, the receiving transducer assembly 2 and the receiving preamplifier circuit board assembly 6 adjacent along the axial direction are specifically connected by a first transmission line. Since the receiving transducer assembly 2 and the corresponding receiving preamplifier circuit board assembly 6 are both disposed on the surface of the skeleton 1 and are adjacent along the axial direction, only a very short first transmission line is needed to connect the two. This allows the small current generated by the receiving transducer assembly 2 to be transmitted to the corresponding receiving preamplifier circuit board assembly 6 for filtering and amplification through only a short path, ensuring that the signal is basically not interfered with during transmission and ensuring that the multipole acoustic wave receiving unit has a high signal-to-noise ratio.

[0049] See Figure 2 as well as Figure 3 Specifically, in this embodiment, the skeleton 1 includes a skeleton body 8 and a sound insulation block 14 that are fixedly connected. The skeleton body 8 and the sound insulation block 14 are arranged sequentially along the axial direction. The skeleton body 8 has a first outer peripheral portion and is provided with the receiving transducer assembly 2. The sound insulation block 14 has a second outer peripheral portion and is provided with the receiving preamplifier circuit board assembly 6.

[0050] In this embodiment, the frame 1 typically consists of two parts: a frame body 8, the outer periphery of which is the first outer periphery described above; and a sound insulation block 14, the outer periphery of which is the second outer periphery described above. The frame body 8 and the sound insulation block 14 need to be arranged sequentially along the axial direction, and the frame body 8 and the sound insulation block 14 typically need to be fixedly connected.

[0051] Specifically, the material of the aforementioned skeleton body 8 is typically non-magnetic stainless steel, meaning the skeleton body 8 is a non-magnetic stainless steel skeleton body 8. The sound insulation block 14 is typically made of a high acoustic impedance material, serving two purposes: firstly, to house the receiving preamplifier circuit board assembly 6 on or within it, and secondly, to isolate or attenuate direct sound wave signals propagating along the axis of the skeleton 1. The sound insulation block 14 typically has an internal metal skeleton for support, and an external protective layer of polytetrafluoroethylene and / or high-temperature fluororubber covering the metal skeleton. The material selection for the sound insulation block 14 usually requires high strength while ensuring its sound insulation performance. Of course, in this embodiment, the specific materials of the skeleton body 8 and the sound insulation block 14 are not specifically limited, depending on the specific circumstances.

[0052] In this embodiment, the end of the frame body 8 is typically provided with screw holes 10, while the end of the sound insulation block 14 is provided with through holes 16. The specific connection method between the frame body 8 and the sound insulation block 14 is to use screws to fasten the sound insulation block 14 onto the frame body 8 through the screw holes 10 and the through holes 16, thereby achieving the connection between the two. Furthermore, the aforementioned screw holes 10 can also be used for orientation positioning, that is, one of the screw holes 10 is a preset orientation, and by keeping the direction of the receiving transducer assembly 2 consistent with the screw hole 10, a relative zero orientation can be achieved.

[0053] Specifically, in this embodiment, a plurality of receiving transducer grooves are uniformly arranged along the circumferential direction on the first outer periphery, and the receiving transducer assembly 2 is fixed in the corresponding receiving transducer groove; the receiving transducer groove is provided with a first notch facing the baffle of the sound insulation block 14, so as to form a receiving line groove 15 based on the first notch; the first transmission line connects the receiving transducer assembly 2 and the receiving preamplifier circuit board assembly 6 through the receiving line groove 15.

[0054] The outer periphery of the aforementioned skeleton body 8 can be provided with multiple receiving transducer grooves. Each receiving transducer groove is mainly used to accommodate the corresponding receiving transducer assembly 2, that is, the receiving transducer assembly 2 is usually fixed in the corresponding receiving transducer groove. Typically, the receiving transducer groove is rectangular, meaning it is usually surrounded by four baffles. The baffle facing the sound insulation block 14 can have a first notch, which forms a receiving cable groove 15. This first notch is usually located at the top of the baffle, and the first transmission line can specifically connect the receiving transducer assembly 2 and the receiving preamplifier circuit board assembly 6 through this receiving cable groove 15. The receiving cable groove 15 formed by the first notch is used for wiring between the receiving transducer assembly 2 and the receiving preamplifier circuit board assembly 6, and it can play a certain role in fixing the wiring, facilitating the electrical connection between the receiving transducer assembly 2 and the receiving preamplifier circuit board assembly 6.

[0055] Furthermore, the connection between the main frame 8 and the sound insulation block 14 can form a spacer groove 12 extending along the circumferential direction, and the spacer groove 12 communicates with the receiving groove 15. In this case, the spacer groove 12 acts as a branch of the receiving groove 15, thus forming a cross-shaped groove structure at the position of the receiving groove 15. For the multipole acoustic wave receiving unit, to ensure signal accuracy, it is necessary to ensure that the signal line lengths between the receiving transducer assembly 2 and the receiving preamplifier circuit board assembly 6 are equal. With the aforementioned spacer groove 12, it can be used to accommodate the signal lines set to ensure equal signal line lengths.

[0056] Specifically, in this embodiment, a wiring groove 13 is formed between adjacent receiving transducer recesses. This wiring groove 13 is used to accommodate wiring connecting the receiving transducer assemblies 2 to each other or to external structures, such as power supplies. At this time, all cables, the receiving preamplifier circuit board assembly 6, and the receiving transducer assembly 2 are exposed on the outer periphery of the frame 1, making them easy to repair and maintain, thereby reducing maintenance costs and improving efficiency.

[0057] Specifically, this embodiment also includes a cable tie; the receiving transducer groove is provided with a second notch facing the baffle wall of the adjacent receiving transducer groove, so as to form a cable tie groove 11 extending in the circumferential direction based on the second notch, and the cable tie is disposed in the cable tie groove 11.

[0058] The aforementioned second notch is typically located at the top of the aforementioned baffle. The cable tie groove 11 formed by this second notch is specifically located at the top of the cable tray 13 and the top of the receiving transducer groove. Correspondingly, the cable ties provided in the cable tie groove 11 can be used to bind and secure the cables installed in the cable tray 13 and the receiving transducer assembly 2 installed in the receiving transducer groove. The cable ties are typically elastic high-temperature rubber cable ties. These cable ties can further secure the receiving transducer assembly 2 to prevent interference signals caused by unwarranted vibration, and can also be used to secure the wires in the cable tray 13 to prevent damage from stress.

[0059] In this embodiment, the receiving transducer assembly 2 is fixed to the first outer periphery by a padding 3, the padding 3 being at least partially located between the receiving transducer assembly 2 and the first outer periphery; and / or, the receiving preamplifier circuit board assembly 6 is fixed to the second outer periphery by a pressure block 5.

[0060] The aforementioned pad 3 is used to fix the receiving transducer assembly 2 to the first outer periphery. The pad 3 is at least partially located between the receiving transducer assembly 2 and the first outer periphery, serving as a buffer structure between the receiving transducer assembly 2 and the surface of the frame 1. The pad 3 is typically made of high-temperature fluororubber. It is usually C-shaped and fixes the receiving transducer assembly 2 from the side. The pad 3 typically includes an upper part, a guardrail, and a base. The base of the pad 3 is adjacent to the bottom of the receiving transducer assembly 2, supporting it. This serves to buffer the receiving transducer assembly 2, forming a protective mechanism, and to prevent radial and lateral movement. The C-shaped structure of the pad 3 prevents vertical movement of the receiving transducer assembly 2. This structure also wraps around the receiving transducer assembly 2, keeping it in a non-free state. This prevents the noise signal generated by the receiving transducer assembly 2 swinging downhole from being converted during acoustic-to-electric conversion, thus ensuring high accuracy and stability of the generated signal. The structure is simple and efficient. In addition, the receiving pad 3 can ensure electrical insulation between the receiving transducer assembly 2 and the frame body 8 to improve signal accuracy and quality. It effectively solves the problem of difficulty in maintenance caused by adding welding pillars to fix the positive and negative poles in the receiving transducer assembly 2.

[0061] The aforementioned pad 3 is usually provided with a fixing screw hole 4 on the upper part. The pad 3 can be fixed to the frame body 8 by screws. The relatively elastic fixing of the receiving transducer assembly 2 by the pad 3 can reduce the pressure of the screw on the receiving transducer assembly 2 to protect the receiving transducer assembly 2. It can also reduce the stress of the welding column on the positive and negative electrodes of the receiving transducer assembly 2 to avoid the positive and negative electrodes peeling off.

[0062] Specifically, the aforementioned receiving preamplifier circuit board assembly 6 can be fixed to the second outer periphery by pressure blocks 5. Specifically, pressure blocks 5 can be set on the upper part of opposite ends of the receiving preamplifier circuit board assembly 6 to fix the receiving preamplifier circuit board assembly 6 and keep it stable downhole. The pressure block 5 can be provided with pressure block screw holes 7. When fixed, the pressure block 5 can be fixed to the sound insulation block 14 by screws through the pressure block screw holes 7. A receiving preamplifier circuit board assembly 6 is usually fixed by two pressure blocks 5 to prevent the measurement noise and damage caused by the vibration of the circuit during the downhole measurement process. The main function of the receiving preamplifier circuit board assembly 6 is to filter, optimize and amplify the electrical signal from the receiving transducer assembly 2 to improve the signal quality and anti-interference performance. The receiving preamplifier circuit board assembly 6 will be exposed to the high temperature and high pressure insulating oil environment downhole. Therefore, in this embodiment, the receiving preamplifier circuit board assembly 6 will specifically use high temperature and high pressure resistant components. The receiving preamplifier circuit board assembly 6 can be the simplest single-layer or double-layer circuit board, using only four components: resistors, capacitors, plastic-encapsulated operational amplifiers, and plastic-encapsulated multiplexers. Moreover, the internal structure of these components is solid without hollow space to withstand the downhole high pressure. After the welding and testing of the preamplifier circuit board assembly 6 are completed, it can be sprayed with an insulating and corrosion-resistant sealing material. This can improve the reliability and stability of the circuit and prevent damage to the circuit board caused by impurities and corrosive gases in the high-temperature oil due to long-term use. This effectively solves the problems of high temperature and high pressure resistance and corrosion resistance of the circuit board.

[0063] The multipole acoustic wave receiving unit provided in this embodiment is usually immersed in silicone oil. When working downhole, it needs to withstand the high temperature and high pressure environment. The multipole acoustic wave receiving unit sets a preamplifier circuit board assembly near the receiving transducer assembly 2 in the frame 1 and electrically connects the adjacent receiving transducer assembly 2 to the preamplifier circuit board assembly. This allows the electrical signal collected by the receiving transducer assembly 2 to be transmitted to the preamplifier circuit board assembly for signal filtering optimization and amplification enhancement over a very short distance. This can effectively improve signal quality and anti-interference performance, giving the multipole acoustic wave receiving unit a high signal-to-noise ratio.

[0064] The specific details of the multipole acoustic wave receiving unit provided by this invention will be described in detail in the following embodiments.

[0065] Example 2

[0066] Please refer to Figures 4 to 7 , Figure 4 This is a schematic diagram of the structure of a specific receiving transducer assembly provided in an embodiment of the present invention; Figure 5 A comparison graph of the sensitivity of the receiving transducer components; Figure 6 This is a schematic diagram of a preamplifier circuit provided in an embodiment of the present invention; Figure 7 This is a comparison diagram of acoustic wave reception signals with and without a preamplifier circuit.

[0067] Unlike the embodiments described above, the embodiments of the present invention further define the structure of the receiving transducer assembly 2 based on the embodiments described above. The remaining details have been described in detail in the embodiments described above and will not be repeated here.

[0068] See Figure 4 In this embodiment of the invention, the receiving transducer assembly 2 includes two piezoelectric ceramic sheets 213 stacked together, the piezoelectric ceramic sheets 213 being polarized along the same thickness direction; the positive electrode side surface of one piezoelectric ceramic sheet 213 is in contact with and electrically connected to the negative electrode side surface of the other piezoelectric ceramic sheet 213, so that the two piezoelectric ceramic sheets 213 are connected in series.

[0069] In this embodiment, the main structure of the receiving transducer assembly 2 consists of two piezoelectric ceramic sheets 213 connected in series. In this embodiment, the piezoelectric ceramic sheets 213 are polarized along their thickness direction; therefore, one surface is the positive electrode side surface, and the other surface is the negative electrode side surface. In this embodiment, the positive electrode side surface of one piezoelectric ceramic sheet 213 contacts and is electrically connected to the negative electrode side surface of the other piezoelectric ceramic sheet 213. That is, the two piezoelectric ceramic sheets 213 are stacked, and the two contacting surfaces are surfaces with opposite electrical polarities, thus connecting the two piezoelectric ceramic sheets 213 in series.

[0070] As shown in the table below, under the same conditions, compared with the parallel method, the capacitance of the receiving transducer assembly 2 in the series method is reduced by three-quarters, the driving capability of the cable is reduced, and the ability to connect long cables is weakened, but the sensitivity is doubled. This is extremely advantageous for receiving weak sound wave signals. In response to the reduction in cable driving capability, this embodiment sets up a receiving preamplifier circuit board assembly 6 near the receiving transducer assembly 2, which can significantly reduce the cable length for receiving sound wave signals and eliminate the adverse effects of weak driving. In addition, the addition of the preamplifier circuit can greatly improve the quality of the received signal and improve the signal's anti-interference ability.

[0071] Table 1. Comparison of Series and Parallel Connections of Piezoelectric Ceramic Sheets

[0072] Comparison of contents in parallel Series capacitance value Sensitivity

[0073] C in the table above p C is the value of the parallel capacitor. s Where S is the series capacitance, h is the area of ​​the piezoelectric ceramic sheet 213, and m is the thickness of the piezoelectric ceramic sheet 213. p For parallel sensitivity, M s For series sensitivity, g 33 Let g be the piezoelectric voltage constant along the crystal polarization direction. 31 Let be the piezoelectric voltage constant in the plane perpendicular to the polarization direction.

[0074] Specifically, in this embodiment, the receiving transducer assembly 2 further includes a negative electrode conductive sheet 211 and a positive electrode conductive sheet 214. The negative electrode conductive sheet 211 is attached to the exposed negative electrode side surface of the two stacked piezoelectric ceramic sheets 213, and the positive electrode conductive sheet 214 is attached to the exposed positive electrode side surface of the two stacked piezoelectric ceramic sheets 213.

[0075] The aforementioned negative electrode conductive sheet 211 and positive electrode conductive sheet 214 are used to bring out the corresponding electrodes. The entire stacked structure can be composed of 7 layers, which can be arranged from top to bottom as follows: negative electrode conductive sheet 211, conductive adhesive 212, piezoelectric ceramic sheet 213, conductive adhesive 212, piezoelectric ceramic sheet 213, conductive adhesive 212, and positive electrode conductive sheet 214. The adjacent sheets in the entire stacked structure are bonded together by conductive adhesive 212.

[0076] The piezoelectric ceramic sheet 213 is usually a rectangular sheet of piezoelectric ceramic. The connection between two piezoelectric ceramic sheets 213 is usually made by uniformly bonding them with high-temperature resistant conductive adhesive 212. Both piezoelectric ceramic sheets 213 are polarized in the thickness direction. The thickness direction of the two piezoelectric ceramic sheets 213 is aligned with the polarization direction and they are neatly stacked. The two piezoelectric ceramic sheets 213 are connected by conductive adhesive 212, that is, the negative electrode of one piezoelectric ceramic sheet 213 is bonded to the positive electrode of the other ceramic sheet.

[0077] When bonding ceramics together or between ceramics and electrodes, the conductive adhesive 212 is preferably used to perform a seamless bonding process at a temperature of 200℃ and a pressure of 200kg for up to 24 hours on two piezoelectric ceramic sheets 213. The preferred dimensions of the piezoelectric ceramic sheet 213 are 50.8mm × 25.4mm × 3.6mm. It has two leads: the aforementioned negative electrode conductive sheet 211 and positive electrode conductive sheet 214. The electrode dimensions are typically the same as the ceramic dimensions, with a thickness of approximately 0.05mm. Protruding solder holes are provided at the electrode leads of the negative electrode conductive sheet 211 and the positive electrode conductive sheet 214 for thorough welding of the wires to the solder holes. The negative electrode conductive sheet 211 and the positive electrode conductive sheet 214 are located at the top and bottom of the two ceramic sheets, respectively. Bonding is completed by only three bonding processes between the positive and negative leads and the ceramic sheets. Two piezoelectric ceramic plates 213 are stacked in sequence according to the polarization direction. The process is simple, and the quality and consistency of the receiving transducer assembly 2 can be easily guaranteed. Moreover, the receiving sensitivity is greatly improved compared with the traditional parallel method. On the one hand, the sensitivity is doubled due to the series method, and on the other hand, the piezoelectric ceramic is thickened by 1mm according to the polarization direction, which can further improve the sensitivity by 4dB. The overall sensitivity is improved by 10dB, which is more than 3 times that of the existing parallel technology.

[0078] like Figure 5As shown, the receiver used in this case has a significantly improved sensitivity compared to traditional parallel receivers. Figure 5 For the sensitivity comparison of series and parallel connections in this embodiment, it can be seen that the sensitivity of the series connection is nearly 3 times higher than that of the parallel connection, approximately 10 dB. The receiving transducer assembly 2 of the above structure is used to receive the acoustic wave signal emitted from the sound source and reflected back by the strata. This assembly is located at the outermost part of the multipole acoustic wave receiving unit, with its negative electrode typically exposed at the outer end and the positive electrode inside.

[0079] See Figure 6 , Figure 6 The circuit diagram of the receiving preamplifier circuit board assembly 6 is shown below. Taking the four-component receiving transducer assembly 2 as an example, the receiving preamplifier circuit board assembly 6 can consist of four circuit boards, which are placed at four positions on the sound insulation block 14 and fixed by the pressure block 5. The electrical signals S from the receiving transducer assembly 2 come from four directions. 东 S 西 S 南 S 北 Impedance matching is performed using equal-length resistors. The matching circuit includes resistors R11, R21, R31, and R41. This circuit completes the impedance matching of the receiving transducer assembly 2 to obtain the maximum signal from the transducer. After signal matching, the signal enters an operational amplifier composed of integrated circuits U1 (including U1A, U1B, U1C, U1D), U6, U7, resistors R100-R112, R12, R22, R32, R42, and capacitors C11, C21, C31, and C41 for variable gain amplification and filtering. The gain is 1, 2, 4, or 8 times. This signal then enters a four-channel differential amplifier integrated circuit U2-U5, with the following differential signals: acoustic wave signals from the east, west, south, and north directions (AC). 东 AC 西 AC 南 AC 北 After difference, we get AC. 西东 =AC 西 -AC 东 AC 北南 =AC 北 - AC 南 AC 西北 =AC 西 - AC 北 AC 西南 =AC 西 - AC 南 Its gain is 16, and the differential gain is controlled by resistors R13, R23, R33, and R43. This forms an AC... 东 AC 西 AC 南 AC 北 AC 西东 AC北南 AC 西北 AC 西南 There are eight electrical signals in total; switch U8 completes the signal selection, selecting AC. 东 AC 西 AC 南 AC 北 Still AC 西东 AC 北南 AC 西北 AC 西南 This reduces the number of signal lines, improving reliability and stability. After selection by switch U8, the signal AC... 东 AC 西 AC 南 AC 北 or AC 西东 AC 北南 AC 西北 AC 西南 The circuit consists of four filter circuits centered around operational amplifier U9 (including U9A, U9B, U9C, and U9D), including resistors R16-R19, capacitors C13-C15, R26-R29, C23-C25, R36-R39, C33-C35, R46-R29, C43-C45, and the four operational amplifiers U9. The frequency bandwidth is typically 300 Hz - 60000 Hz.

[0080] In this embodiment, the receiving preamplifier board assembly 6 will specifically adopt a single-layer board or a double-layer board. Its core components are only surface-mount metal film resistors, surface-mount ceramic capacitors, surface-mount plastic-encapsulated operational amplifiers, and surface-mount plastic-encapsulated electronic switching circuits. It has high reliability and stability, strong confining pressure resistance, and can withstand the high temperature and high pressure environment downhole. All eight output signals are transmitted via shielded cables. This can form eight multipole acoustic wave signals, four component acoustic wave signals, and four differential composite acoustic wave signals, which facilitates the extraction of high-quality acoustic wave signals in ultra-soft formations. It can also be used to receive azimuth acoustic waves in component and differential modes separately for later identification of the azimuth of external anomalies.

[0081] Please refer to the following: Figure 7 The left image shows the acoustic signal received without a preamplifier circuit, while the right image shows the acoustic signal received after adding a preamplifier circuit. It can be seen that the signal quality after adding a preamplifier circuit is significantly improved in signal-to-noise ratio compared to conventional multipole acoustic signals without a preamplifier circuit, which is beneficial for the reception of multipole acoustic signals.

[0082] Currently, conventional multipole acoustic wave receiver units only contain sheet piezoelectric ceramics. In soft ground layers such as sponges, the converted electrical signal is extremely weak, typically a few mV. Interference on the transmission cable is also a few mV, making the interference signal about twice the strength of the useful signal. This is undoubtedly extremely detrimental to acoustic wave signal reception. When these useful and interference signals are fed into subsequent preamplifier and filter circuits, they are synchronously amplified and filtered, but the signal-to-noise ratio remains poor and doesn't change significantly. This technical solution combines the receiving preamplifier circuit board assembly 6 with the piezoelectric ceramic sheet 213 in the receiving transducer assembly 2 in close proximity. This amplifies the useful signal by 10 times, reaching tens of mV. The amplified signal is then transmitted via a transmission cable to an isolated circuit unit. This reduces the interference on the transmission line to only one-tenth of the useful signal, significantly improving the signal-to-noise ratio.

[0083] Example 3

[0084] The following describes a multipole acoustic wave receiving device provided by an embodiment of the present invention. The multipole acoustic wave receiving device described below can be referred to in correspondence with the multipole acoustic wave receiving unit described above.

[0085] See Figures 1 to 3 In this embodiment, the multipole acoustic wave receiving device includes multiple multipole acoustic wave receiving units provided in any of the above-described embodiments. The specific structure of the multipole acoustic wave receiving unit has been described in detail in the above-described embodiments and will not be repeated here. Other structures of the multipole acoustic wave receiving device, such as the housing, can be found in the prior art and will not be repeated here.

[0086] In this embodiment, multiple multipole acoustic wave receiving units are typically fixed sequentially along an axial direction. Correspondingly, the aforementioned frame 1 may further include a through hole 9 extending through the frame 1 along the axial direction, with a fixing cable disposed within the through hole 9. The multiple multipole acoustic wave receiving units are distributed along the axial direction and connected by the fixing cable. The through hole 9 can extend through both ends of the frame 1, allowing the multiple multipole acoustic wave receiving units to be fixedly connected using fixing cables based on the through hole 9. The fixing cable is typically a steel cable, and the through hole 9 specifically needs to extend through the frame body 8 and the sound insulation block 14 along the axial direction.

[0087] Since the multipole acoustic wave receiving device provided in this embodiment specifically uses the multipole acoustic wave receiving unit provided in the above embodiment, the multipole acoustic wave receiving device can have a higher signal-to-noise ratio, thereby having better performance.

[0088] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0089] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0090] The foregoing has provided a detailed description of the multipole acoustic wave receiving unit and the multipole acoustic wave receiving device provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are merely for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A multipole acoustic wave receiving unit, characterized in that, The skeleton includes a frame, the outer periphery of which includes a first outer periphery and a second outer periphery distributed along the axial direction; The first outer periphery is provided with a plurality of receiving transducer assemblies evenly distributed along the circumferential direction, and the second outer periphery is provided with a plurality of receiving preamplifier circuit board assemblies distributed along the circumferential direction. The receiving transducer assembly is electrically connected to the receiving preamplifier circuit board assembly adjacent along the axial direction via a first transmission line.

2. The multipole acoustic wave receiving unit according to claim 1, characterized in that, The frame includes a frame body and a sound insulation block that are fixedly connected, and the frame body and the sound insulation block are arranged sequentially along the axial direction; The main frame has a first outer periphery and is provided with the receiving transducer assembly; the sound insulation block has a second outer periphery and is provided with the receiving preamplifier circuit board assembly.

3. The multipole acoustic wave receiving unit according to claim 2, characterized in that, The first outer periphery is uniformly provided with a plurality of receiving transducer grooves along the circumferential direction, and the receiving transducer assembly is fixed in the corresponding receiving transducer groove. The receiving transducer groove is provided with a first notch facing the baffle of the sound insulation block to form a receiving cable groove based on the first notch; the first transmission line connects the receiving transducer assembly and the receiving preamplifier circuit board assembly through the receiving cable groove.

4. The multipole acoustic wave receiving unit according to claim 3, characterized in that, The connection between the main frame body and the sound insulation block is formed with a spaced groove extending along the circumferential direction, and the spaced groove is in communication with the receiving groove.

5. The multipole acoustic wave receiving unit according to claim 3, characterized in that, A wiring groove is formed between adjacent receiving transducer recesses.

6. The multipole acoustic wave receiving unit according to claim 3, characterized in that, It also includes cable ties; The receiving transducer groove is provided with a second notch facing the baffle wall of the adjacent receiving transducer groove, so as to form a cable tie groove extending in the circumferential direction based on the second notch, and the cable tie is disposed in the cable tie groove.

7. The multipole acoustic wave receiving unit according to claim 2, characterized in that, The receiving transducer assembly is fixed to the first outer periphery by a pad, and the pad is at least partially located between the receiving transducer assembly and the first outer periphery; And / or, the receiving preamplifier circuit board assembly is fixed to the second outer periphery by a clamping block.

8. The multipole acoustic wave receiving unit according to any one of claims 1 to 7, characterized in that, The receiving transducer assembly includes two piezoelectric ceramic sheets stacked together, wherein the piezoelectric ceramic sheets are polarized along the thickness direction; The positive electrode side surface of one of the piezoelectric ceramic sheets is in contact with and electrically connected to the negative electrode side surface of the other piezoelectric ceramic sheet, so that the two piezoelectric ceramic sheets are connected in series.

9. A multipole acoustic wave receiving device, characterized in that, It includes multiple multipole acoustic wave receiving units as described in any one of claims 1 to 8.

10. The multipole acoustic wave receiving device according to claim 9, characterized in that, The frame includes a through hole extending through the frame along the axial direction, and a fixing cable is disposed in the through hole; Multiple multipole acoustic wave receiving units are distributed along the axial direction and are connected by the fixed cable.

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