Sound wave detection receiving unit

Abstract

The invention discloses a sound wave detection receiving unit, which is applied to the technical field of oil well logging and comprises a columnar framework, and a pressure-bearing bin is arranged in the framework; one end of the pressure-bearing bin along the axis direction of the framework is an opening, and the other end is a bottom; a plurality of receiving transducer assemblies which are evenly distributed in the circumferential direction are arranged on the periphery of the framework, a receiving front-placing circuit board assembly is arranged in the pressure bearing bin, and the receiving transducer assemblies are electrically connected with the receiving front-placing circuit board assembly; the pre-placed circuit board receiving assembly comprises a pre-placed circuit board and a pressure-bearing block welded to the pre-placed circuit board, and the pressure-bearing block is connected with the opening of the pressure-bearing bin in a sealed mode. By arranging the receiving pre-amplification circuit board assembly in the skeleton, the receiving transducer assembly can be electrically connected with the pre-amplification circuit board assembly, so that the signal quality and the anti-interference performance can be effectively improved, and the sound wave receiver has a high signal-to-noise ratio. And the pressure-bearing block is sealed, so that the circuit board assembly before receiving can be suitable for a high-temperature and high-pressure environment of a deep well.

Description

Technical Field

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

[0002] The acoustic wave remote sensing receiver unit mainly consists of multiple multi-electrode piezoelectric ceramic receivers. These piezoelectric ceramic receivers are immersed in silicone oil and encapsulated by a pressure balancing device to isolate them from the liquid inside the wellbore. The pressure and temperature at the receiving piezoelectric ceramic location are basically the same as those in the wellbore. However, as the wellbore depth increases, the downhole pressure and temperature rise continuously, causing a sharp decline in the sensitivity and performance of these piezoelectric ceramics, making it impossible to accurately receive acoustic signals, especially those from deep wells.

[0003] The acoustic long-range detection multi-pole receiver unit needs to receive the reflected acoustic waves, which requires high accuracy and quality in receiving acoustic signals. In deep wells, the performance of the piezoelectric ceramic receiving signal degrades, which greatly affects the effective reception of the reflected acoustic waves.

[0004] Oil resources below 7000 meters have become one of the main sources of current oil production. Deep wells exceeding 7000 and 8000 meters are constantly emerging in various regions. These wells are characterized by high temperature and high pressure. Currently, acoustic detection in these wells is conducted at the expense of signal quality, which is extremely detrimental to subsequent signal processing and fracture identification. Therefore, how to provide a method to achieve a high signal-to-noise ratio for acoustic detection signals under the high temperature and high pressure environment of deep wells 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 an acoustic wave detection and receiving unit that can achieve a high signal-to-noise ratio for acoustic wave long-distance detection signals in deep well high-temperature and high-pressure environments.

[0006] To solve the above-mentioned technical problems, the present invention provides an acoustic wave detection and receiving unit, including a columnar frame, wherein a pressure-bearing chamber is disposed inside the frame; one end of the pressure-bearing chamber is open along the axial direction of the frame, and the other end is the bottom;

[0007] The outer periphery of the skeleton is provided with a plurality of receiving transducer assemblies evenly distributed in the circumferential direction, and the pressure chamber is provided with a receiving preamplifier circuit board assembly. The receiving transducer assembly is electrically connected to the receiving preamplifier circuit board assembly.

[0008] The receiving preamplifier circuit board assembly includes a preamplifier circuit board and a pressure-bearing block welded to the preamplifier circuit board, wherein the pressure-bearing block is sealed to the opening of the pressure-bearing chamber.

[0009] Optionally, the first end of the preamplifier circuit board is fixedly connected to the pressure block, and a sealing disc is provided at the second end of the preamplifier circuit board opposite to the first end. A slot is provided on the surface of the sealing disc, and the second end of the preamplifier circuit board is inserted into the slot.

[0010] Optionally, the outer periphery of the pressure block is provided with at least one sealing ring in the circumferential direction.

[0011] Optionally, the pressure block is provided with a connector that penetrates the pressure block along the axial direction. The end of the connector near the preamplifier circuit board is soldered to the gold finger of the preamplifier circuit board, and the end of the connector away from the preamplifier circuit board protrudes from the surface of the pressure block.

[0012] Optionally, an insulating layer is provided between the pressure-bearing block and the connector.

[0013] Optionally, it also includes a socket located on the side of the pressure block away from the front circuit board, wherein the female connector in the socket is connected to the corresponding connector.

[0014] Optionally, the socket may have a tie post extending along the axial direction on the surface away from the pressure block.

[0015] Optionally, the receiving transducer assembly is fixed to the outer periphery of the frame by a fixing sleeve, the fixing sleeve being at least partially located between the receiving transducer assembly and the outer periphery of the frame.

[0016] Optionally, the receiving transducer assembly includes two stacked piezoelectric ceramic sheets, which are polarized along the thickness direction;

[0017] 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.

[0018] Optionally, the receiving transducer assembly further includes a negative electrode conductive sheet and a positive electrode conductive sheet, wherein the negative electrode conductive sheet is bonded to the exposed negative electrode side surface of the two stacked piezoelectric ceramic sheets, and the positive electrode conductive sheet is bonded to the exposed positive electrode side surface of the two stacked piezoelectric ceramic sheets.

[0019] The present invention provides an acoustic wave detection and receiving unit, comprising a columnar frame, with a pressure chamber disposed inside the frame; one end of the pressure chamber is open along the axial direction of the frame, and the other end is the bottom; a plurality of receiving transducer assemblies are disposed on the outer periphery of the frame and evenly distributed in the circumferential direction; a receiving preamplifier circuit board assembly is disposed inside the pressure chamber, and the receiving transducer assemblies are electrically connected to the receiving preamplifier circuit board assembly; the receiving preamplifier circuit board assembly includes a preamplifier circuit board and a pressure block welded to the preamplifier circuit board, and the pressure block is sealed to the opening of the pressure chamber.

[0020] By placing the receiving preamplifier circuit board assembly inside the frame, the receiving transducer assembly can be electrically connected to it in close proximity. This allows the electrical signal collected by the receiving transducer assembly to be transmitted to the preamplifier circuit board assembly over a very short distance for signal filtering, optimization, and amplification. This effectively improves signal quality and anti-interference performance, resulting in a high signal-to-noise ratio for the acoustic receiver. Furthermore, placing the receiving preamplifier circuit board assembly within a pressure-bearing chamber inside the frame and sealing it with pressure blocks makes it suitable for use in deep well high-temperature and high-pressure environments. Attached Figure Description

[0021] 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.

[0022] Figure 1 This is a schematic diagram of the structure of an acoustic wave detection and receiving unit provided in an embodiment of the present invention;

[0023] Figure 2 for Figure 1 A schematic diagram of the structure of the receiver preamplifier circuit board assembly;

[0024] Figure 3 This is a schematic diagram of the structure of a specific receiving transducer assembly provided in an embodiment of the present invention;

[0025] Figure 4 A comparison graph of the sensitivity of the receiving transducer components;

[0026] Figure 5 This is a partial schematic diagram of an acoustic wave detection and receiving unit provided in an embodiment of the present invention;

[0027] Figure 6 This is a schematic diagram of a preamplifier circuit provided in an embodiment of the present invention;

[0028] Figure 7This is a comparison diagram of acoustic wave reception signals with and without a preamplifier circuit.

[0029] In the diagram: 1. Acoustic wave detection and receiving unit, 2. Receiving transducer assembly, 4. Frame, 5. Receiving preamplifier circuit board assembly, 6. Pressure chamber, 7. Socket, 8. Cover plate, 9. Cable tie post;

[0030] 21. Fixing sleeve; 22. Screw; 211. Negative electrode conductive sheet; 212. Conductive adhesive; 213. Piezoelectric ceramic sheet; 214. Positive electrode conductive sheet;

[0031] 51. Front-end circuit board, 52. Pressure block, 53. Sealing ring, 54. Retaining ring, 55. Connector, 56. Insulation layer, 57. Soldering material, 58. Sealing disc, 59. Screw hole. Detailed Implementation

[0032] The core of this invention is to provide an acoustic wave detection receiving unit. In the prior art, deep wells are characterized by high temperature and high pressure. The implementation of acoustic wave detection receiving structures in these wells is currently carried out at the expense of signal quality, which is extremely detrimental to subsequent signal processing and fracture identification.

[0033] The acoustic wave detection and receiving unit provided by the present invention includes a columnar frame with a pressure chamber inside. One end of the pressure chamber is open along the axis of the frame, and the other end is the bottom. A plurality of receiving transducer assemblies are evenly distributed in the circumferential direction on the outer periphery of the frame. A receiving preamplifier circuit board assembly is disposed inside the pressure chamber. The receiving transducer assemblies are electrically connected to the receiving preamplifier circuit board assembly. The receiving preamplifier circuit board assembly includes a preamplifier circuit board and a pressure block welded to the preamplifier circuit board. The pressure block is sealed to the opening of the pressure chamber.

[0034] By placing the receiving preamplifier circuit board assembly inside the frame, the receiving transducer assembly can be electrically connected to it in close proximity. This allows the electrical signal collected by the receiving transducer assembly to be transmitted to the preamplifier circuit board assembly over a very short distance for signal filtering, optimization, and amplification. This effectively improves signal quality and anti-interference performance, resulting in a high signal-to-noise ratio for the acoustic receiver. Furthermore, placing the receiving preamplifier circuit board assembly within a pressure-bearing chamber inside the frame and sealing it with pressure blocks makes it suitable for use in deep well high-temperature and high-pressure environments.

[0035] 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.

[0036] Example 1

[0037] Please refer to Figure 1 as well as Figure 2 , Figure 1 This is a schematic diagram of the structure of an acoustic wave detection and receiving unit provided in an embodiment of the present invention; Figure 2 for Figure 1 A schematic diagram of the structure of the receiver preamplifier circuit board assembly.

[0038] See Figure 1 as well as Figure 2 In this embodiment of the invention, the acoustic wave detection and receiving unit 1 includes a columnar frame 4, and a pressure-bearing chamber 6 is disposed inside the frame 4. The pressure-bearing chamber 6 has an opening at one end and a bottom at the other end along the axial direction of the frame 4. A plurality of receiving transducer assemblies 2 are uniformly distributed in the circumferential direction on the outer periphery of the frame 4. A receiving preamplifier circuit board assembly 5 is disposed inside the pressure-bearing chamber 6. The receiving transducer assemblies 2 are electrically connected to the receiving preamplifier circuit board assembly 5. The receiving preamplifier circuit board assembly 5 includes a preamplifier circuit board 51 and a pressure-bearing block 52 welded to the preamplifier circuit board 51. The pressure-bearing block 52 is sealed to the opening of the pressure-bearing chamber 6.

[0039] The aforementioned frame 4 is the main supporting structure of the acoustic wave detection and receiving unit 1. It is typically columnar, thus having three directions: axial, circumferential, and radial. The frame 4 needs to be electromagnetically shielded to ensure the performance of the acoustic wave detection and receiving unit 1. Specifically, the main body of the frame 4 can be made of stainless steel electromagnetic shielding metal, meaning the frame 4 can be a stainless steel electromagnetically shielded frame 4. This material results in a large frame 4 mass, preventing vibrations generated during acoustic signal reception from causing noise to the receiving transducer assembly 2, thereby further improving the acoustic signal reception quality of the multipole acoustic wave receiving unit. The electromagnetic shielding material prevents electromagnetic signals generated during acoustic wave transmission from interfering with the high-precision reception of the receiving transducer assembly 2, thus improving the quality of the received signal. Of course, in this embodiment, the specific material of the frame 4 is not specifically limited and depends on the specific situation. In this embodiment, the diameter of the frame 4 is typically less than 70mm to ensure that the receiving device composed of the acoustic wave detection and receiving unit 1 can be effectively used in wellbore environments with diameters of 120mm and below.

[0040] The outer periphery of the aforementioned skeleton 4 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. 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 situation. The aforementioned receiving transducer assembly 2 is the main body for receiving acoustic signals, and it typically converts acoustic wave fluctuation signals into electrical signals through the piezoelectric ceramic sheet 213 therein. The specific structure of the receiving transducer assembly 2 will be described in detail in the following embodiments of the invention, and will not be repeated here.

[0041] The aforementioned pressure chamber 6 is a cavity formed by an opening in the radial center of the frame 4. It is used to accommodate the receiving preamplifier circuit board assembly 5. The pressure chamber 6 has an opening at the top along the axis of the frame 4 and is sealed at the bottom. The distance between the outer boundary of the pressure chamber 6 and the outer shell of the frame 4 is usually not less than 7mm, so as to ensure that after the receiving preamplifier circuit board assembly 5 is placed in the pressure chamber 6, the outer wall of the pressure chamber 6 can withstand a pressure of 250Mpa in the well, so as to protect the receiving preamplifier circuit board assembly 5 from the damage to the circuit by the high pressure in the well.

[0042] The aforementioned receiving preamplifier circuit board assembly 5 is placed inside the pressure chamber 6. This assembly must include at least a preamplifier circuit board 51 and a pressure block 52 welded to it. It typically also includes a sealing ring 53, a retaining ring 54, a connector 55, an insulating layer 56, solder 57, a sealing disc 58, screw holes 59, and other structures. In this embodiment, to ensure the reliability and stability of the receiving preamplifier circuit board assembly 5, the preamplifier circuit board 51 is typically less than 50mm in length and less than 20mm in width. It employs a simple single-layer board design, minimizing the number of components. Preferably, it only includes three types of components: high-temperature surface mount resistors, high-temperature surface mount capacitors, and high-temperature multi-channel low-power operational amplifiers. Its main function is to filter and enhance the electrical signal converted from the receiving transducer assembly 2, improving signal quality and anti-interference capabilities.

[0043] The aforementioned pressure-bearing block 52 is sealed to the opening of the pressure chamber 6, ensuring that the front-end circuit board 51 installed inside the pressure chamber 6 is not corroded by external high-pressure liquid, thus effectively protecting the circuit board. Specifically, at least one sealing ring 53 is provided around the outer periphery of the pressure-bearing block 52 in the circumferential direction. In this embodiment, two sealing rings 53 are preferably provided. These sealing rings 53 can be perfluoroether sealing rings 53, used to achieve sealing and isolation at both ends of the pressure-bearing block 52, ensuring that the pressure-bearing block 52 can be sealed to the opening of the pressure chamber 6. Furthermore, in this embodiment, a retaining ring 54 can be provided between the sealing ring 53 and the pressure-bearing block 52. This retaining ring 54 can be a high-temperature PEEK retaining ring 54, which is used to ensure that the radial compression of the sealing ring 53 is not too large during high-pressure sealing, so as to ensure the sealing effectiveness under high-pressure environment.

[0044] In this embodiment, the first end of the preamplifier circuit board 51 is fixedly connected to the pressure block 52. A sealing disc 58 is provided at the second end of the preamplifier circuit board 51 opposite to the first end. A slot is provided on the surface of the sealing disc 58, and the second end of the preamplifier circuit board 51 is inserted into the slot. The sealing disc 58 can be a disc made of PTFE (polytetrafluoroethylene) material. The sealing disc 58 has a straight slot that runs through the center of the disc. The slot can be tightly inserted into the end of the preamplifier circuit board 51. That is, the pressure block 52 can be specifically located at the first end of the preamplifier circuit board 51, and the sealing disc 58 is located at the end of the preamplifier circuit board 51. PTFE material has good ductility, which can effectively avoid the adverse effects of tension caused by the expansion and contraction of the preamplifier circuit board 51 due to high temperature on its circuit. This further ensures that the preamplifier circuit board 51 does not deform at high temperature, improves the reliability and stability of the preamplifier circuit board 51, and can also reduce the vibration of the preamplifier circuit board 51 in the well, playing a shock absorption and buffering role to further protect the preamplifier circuit board 51 and improve its reliability and stability. It can also reduce the interference vibration of the receiving transducer assembly 2 caused by this, and improve the signal-to-noise ratio.

[0045] In this embodiment, the pressure block 52 is provided with a connector 55 that penetrates the pressure block 52 along the axial direction. One end of the connector 55 near the preamplifier circuit board 51 is soldered to the gold finger of the preamplifier circuit board 51, and the other end of the connector 55 away from the preamplifier circuit board 51 protrudes from the surface of the pressure block 52.

[0046] The connector 55 is mainly used to realize the electrical connection between the preamplifier circuit board 51 and the outside. The end of the connector 55 that extends into the pressure chamber 6, that is, the end near the preamplifier circuit board 51, is the inner plug. This inner plug is usually the end with solder cups. At least some of the inner plugs of the connector 55, such as the inner plugs in the middle two rows, can make close contact with the gold finger pads on the upper and lower surfaces of the preamplifier circuit board 51. This structure can ensure a good connection on the one hand, and on the other hand, the solder 57 located at the end of the connector 55 near the preamplifier circuit board 51 melts when soldering with the preamplifier circuit board 51 to further enhance the strength of the connection between the preamplifier circuit board 51 and the connector 55. The other solder cups of the inner plug of the connector 55 can be electrically connected to the preamplifier circuit board 51 by melting the high-temperature solder 57 with high-temperature wires. This can ensure the firmness of its electrical connection and good shock resistance, thereby improving reliability. The connector 55 is usually a high-temperature gold-plated connector 55. Of course, its material is not specifically limited in this embodiment and depends on the specific situation.

[0047] In this embodiment, an insulating layer 56 is provided between the pressure block 52 and the connector 55. This insulating layer 56 can be a high-temperature engineering ceramic to form electrical insulation between the connector 55 and the pressure block 52, ensuring that the signal flowing through the connector 55 flows normally without short-circuiting to the pressure block 52. The screw holes 59 provided on the pressure block 52 are used for removing the receiving preamplifier circuit board assembly 5, that is, removing the receiving preamplifier circuit board assembly 5 from the pressure chamber 6 using a special tool. The main body of the pressure block 52 is usually made of high-strength stainless steel electromagnetic shielding material.

[0048] This embodiment also includes a socket 7 located on the side of the pressure block 52 away from the preamplifier circuit board 51. The female connector in the socket 7 is connected to the connector 55. The end of the connector 55 away from the preamplifier circuit board 51, that is, the end protruding from the surface of the pressure block 52 away from the preamplifier circuit board 51, is usually an external male connector. This external male connector is connected to the socket 7, such as an 18-pin socket 7. In this case, the socket 7 is located on the side of the pressure block 52 away from the preamplifier circuit board 51. The socket 7 is provided with a female connector, such as an 18-pin gold-plated female connector. This female connector is connected to the external male connector in the connector 55. A retainer can be provided inside the female connector to ensure a good electrical connection with the external male connector. In addition, a cover plate 8, such as a stainless steel metal cover plate 8, can be provided on the side of the socket 7 away from the preamplifier circuit board 51. In this case, the cover plate 8 can be used to press the socket 7 with screws or other connecting structures. This can ensure a tight connection between the male and female connectors and prevent the female connector from detaching from the external male connector due to the force of the connecting wires, thereby improving the reliability of the connection.

[0049] In this embodiment, a wire tie post 9 extending along the axial direction is provided on the surface of the socket 7 away from the pressure block 52. The wire tie post 9 is usually arranged at the center of the socket 7 to fix and bundle the wires soldered to the socket 7. The wire tie post 9 is used for compact wiring, saving space and effectively protecting the wires from being crushed or damaged by external connectors.

[0050] During downhole logging, the acoustic wave detection receiving unit 1 is usually immersed in high-temperature insulating oil. This ensures that the pressure and temperature at the outer edge of the acoustic wave detection receiving unit 1 are the same as the temperature and pressure downhole. Meanwhile, the pressure chamber 6 can be kept at normal pressure, effectively preventing the preamplifier circuit board 51 from being exposed to high pressure. This greatly improves its reliability and stability in the high-pressure environment of deep wells. The pressure block 52 can be made of electromagnetically shielded stainless steel. This material can effectively shield electromagnetic interference generated by the sound source emission, further improving the accuracy of the receiving signal amplification circuit.

[0051] The acoustic wave detection and receiving unit 1 provided in this embodiment, by setting a receiving preamplifier circuit board assembly 5 inside the frame 4, allows the receiving transducer assembly 2 to be electrically connected to the preamplifier circuit board 51 assembly in close proximity. This enables the electrical signal collected by the receiving transducer assembly 2 to be transmitted to the preamplifier circuit board 51 assembly over a very short distance for signal filtering, optimization, and amplification, effectively improving signal quality and anti-interference performance, resulting in a high signal-to-noise ratio for the acoustic wave receiver. Furthermore, by placing the receiving preamplifier circuit board assembly 5 inside the pressure chamber 6 of the frame 4 and sealing it with a pressure block 52, the receiving preamplifier circuit board assembly 5 can be used in deep well high-temperature and high-pressure environments.

[0052] The specific details of the acoustic wave detection and receiving unit 1 provided by the present invention will be described in detail in the following embodiments.

[0053] Example 2

[0054] Please refer to Figures 3 to 7 , Figure 3 This is a schematic diagram of the structure of a specific receiving transducer assembly provided in an embodiment of the present invention; Figure 4 A comparison graph of the sensitivity of the receiving transducer components; Figure 5 This is a partial schematic diagram of an acoustic wave detection and receiving unit provided in an embodiment of the present invention; 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.

[0055] 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.

[0056] See Figure 3 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 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.

[0057] 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.

[0058] 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 instruments that detect weak reflected signals from distant sound waves. To address the reduction in cable driving capability, this embodiment sets up a receiving preamplifier circuit board assembly 5 near the receiving transducer assembly 2, which can significantly reduce the cable length for receiving sound waves 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, with the original received signal sensitivity increasing by 6 dB and the signal anti-interference capability also improved.

[0059] Table 1. Comparison of Series and Parallel Connections of Piezoelectric Ceramic Sheets

[0060] Comparison of contents in parallel Series capacitance value Sensitivity

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] When using conductive adhesive 212 to bond ceramics together or between ceramics and electrodes, it is preferable to perform a seamless bonding process on two piezoelectric ceramic sheets 213 at a temperature of 230℃ and a pressure of 300kg for 24 hours. The preferred dimensions of the piezoelectric ceramic sheet 213 are 50.8mm × 25.4mm × 3.6mm. It has two leads: a negative conductive sheet 211 and a positive 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 and positive conductive sheets 211 and 214 for thorough welding of the wires to the solder holes. The negative and positive conductive sheets 211 and 214 are located at the top and bottom of the two ceramic sheets, respectively. Bonding is completed by only three bonding operations between the positive and negative leads and the ceramic sheets. Two piezoelectric ceramic plates 213 are stacked sequentially according to their polarization direction. This simplifies the process and ensures the quality and consistency of the receiving transducer assembly 2. Furthermore, the receiving sensitivity is significantly improved compared to the traditional parallel connection method. This is due to two factors: firstly, the series connection doubles the sensitivity; secondly, the piezoelectric ceramic is thickened by 1mm according to the polarization direction, further increasing the sensitivity by 4dB. The overall sensitivity improvement is 10dB, more than three times that of existing parallel technologies. Figure 4 As can be seen from the diagram, the receiving transducer assembly 2 used in this embodiment has a significantly improved sensitivity compared to the traditional parallel connection.

[0066] like Figure 4 As shown, the receiving transducer assembly 2 used in this embodiment has a significantly improved sensitivity compared to the traditional parallel connection. Figure 4 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 acoustic wave detection and receiving unit 1, with its negative electrode typically exposed at the outer end and the positive electrode inside.

[0067] See Figure 5 In this embodiment, the receiving transducer assembly 2 is fixed to the outer periphery of the frame 4 by a fixing sleeve 21, the fixing sleeve 21 being at least partially located between the receiving transducer assembly 2 and the outer periphery of the frame 4. The piezoelectric ceramic sheet 213 in the receiving transducer assembly 2 is used to receive acoustic wave signals and convert acoustic wave pressure and vibration signals into electrical signals, which are then sent to the preamplifier circuit in the receiving preamplifier circuit board assembly 5 for signal filtering, optimization, and amplification. The aforementioned fixing sleeve 21 is embedded with the receiving transducer assembly 2. The lower part of the fixing sleeve 21, located between the receiving transducer assembly 2 and the surface of the frame 4, is an elastic sleeve. On the one hand, it can buffer the downhole pressure on the receiving transducer assembly 2 to protect it. On the other hand, it can ensure the non-free vibration of the receiving transducer assembly 2 to effectively perform acoustic-electric conversion. The upper surface of the receiving transducer assembly 2 is usually exposed, and both ends are embedded in the fixing sleeve 21. The two ends of the fixing sleeve 21 can be fixed with connecting parts such as screws 22 to fix the fixing sleeve 21 to the outer periphery of the frame 4. This prevents the receiving transducer assembly 2 from swinging randomly downhole, which would cause instability in the acoustic wave reception signal, and prevents the reception of noise signals. This ensures that the piezoelectric ceramic sheet 213 performs high-precision and high-stability conversion of acoustic wave signals. This structure is simple and efficient, effectively solving the problem of difficult maintenance caused by adding welding posts to fix the positive and negative electrodes of the piezoelectric ceramic sheet 213. In addition, the use of the fixing sleeve 21 for elastic fixing connection can reduce the pressure of the screw 22 on the receiving transducer assembly 2 to protect the piezoelectric ceramic sheet 213 inside, and can also reduce the torque of the welding posts on the positive and negative electrodes of the piezoelectric ceramic sheet 213 to prevent the positive and negative electrodes from peeling off from the piezoelectric ceramic sheet 213. Furthermore, the fixing sleeve 21 can ensure that the receiving transducer assembly 2 is insulated from the frame 4 to ensure the accuracy of the signal.

[0068] Conventional acoustic wave remote detection receiver units contain only sheet piezoelectric ceramics. In the strata, the converted electrical signal is extremely weak, typically only a few mV. Interference on the transmission cable also reaches a few mV, meaning the interference signal is approximately 100% of the useful signal strength. 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. In this embodiment, the receiving preamplifier circuit board assembly 5 and the receiving transducer assembly 2 are combined close together. On one hand, the useful signal is amplified tenfold, reaching tens of mV. The amplified signal is then transmitted via a transmission cable to the isolated receiving preamplifier circuit board assembly 5. This reduces the interference on the transmission line to only about 10% of the useful signal, improving the signal-to-noise ratio by nearly tenfold.

[0069] See Figure 6 , Figure 6 The circuit diagram of the receiving preamplifier circuit board assembly 5 is shown below. Taking the four-component receiving transducer assembly 2 as an example, the receiving preamplifier circuit board assembly 5 in this embodiment includes four identical amplification and filtering circuits. Each receiving transducer assembly 2 is connected to one signal. The signal from the receiving transducer assembly 2 after acoustic-to-electric conversion is first impedance matched. The impedance matching circuit includes R1, R4, R7, and R10. This circuit completes the impedance matching of the receiving transducer assembly 2 to obtain the maximum signal from the receiving transducer assembly 2. After signal matching, the signal is amplified and filtered. This circuit is amplified and filtered by capacitors C1-C4, resistors R2, R3, R5, R6, R8, R9, R11, R12, and amplifier AMP1. The gain of the circuit can be 3, and the bandwidth is usually between 300 Hz and 30000 Hz.

[0070] in Figure 7 The left image shows the acoustic signal received without a preamplifier circuit board, while the right image shows the acoustic signal received with an active preamplifier circuit board. It can be seen that the signal quality after adding the preamplifier circuit board is greatly improved in signal-to-noise ratio compared with conventional far-field acoustic signals without a preamplifier circuit, which is beneficial for the reception of far-field acoustic reflected wave signals.

[0071] The acoustic wave detection and receiving unit 1 provided in this embodiment uses a pressure chamber 6 to house the receiving preamplifier circuit board assembly 5 and sets up a series receiving preamplifier circuit board assembly 5. This results in high acoustic wave reception sensitivity. The preamplifier circuit is located near the receiving preamplifier circuit board assembly 5 within the pressure chamber 6. This avoids long-distance cable transmission and allows for signal optimization and enhancement through the preamplifier circuit, improving the accuracy and signal-to-noise ratio of the received signal, enhancing signal anti-interference capabilities, and solving the problem of high-precision measurement using long-distance acoustic wave detection in deep earth and deep sea environments. The aforementioned acoustic wave detection and receiving unit 1 can meet the high-sensitivity reception requirements of long-distance acoustic wave logging instruments for deep earth and deep sea acoustic wave logging. It offers advantages such as improved sensitivity and accuracy of acoustic wave reception signals, enhanced temperature and pressure resistance, and improved signal stability and reliability for receiving weak acoustic wave signals in deep earth and deep sea environments.

[0072] 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.

[0073] 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.

[0074] The acoustic wave detection and receiving unit provided by the present invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only 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 several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A sound wave detection and receiving unit, characterized in that, It includes a columnar frame, and a pressure chamber is provided inside the frame; the pressure chamber is open at one end and bottom at the other end along the axial direction of the frame; The outer periphery of the skeleton is provided with a plurality of receiving transducer assemblies evenly distributed in the circumferential direction, and the pressure chamber is provided with a receiving preamplifier circuit board assembly. The receiving transducer assembly is electrically connected to the receiving preamplifier circuit board assembly. The receiving preamplifier circuit board assembly includes a preamplifier circuit board and a pressure-bearing block welded to the preamplifier circuit board, wherein the pressure-bearing block is sealed to the opening of the pressure-bearing chamber.

2. The acoustic wave detection and receiving unit according to claim 1, characterized in that, The first end of the preamplifier circuit board is fixedly connected to the pressure block. A sealing plate is provided at the second end of the preamplifier circuit board opposite to the first end. A slot is provided on the surface of the sealing plate, and the second end of the preamplifier circuit board is inserted into the slot.

3. The acoustic wave detection and receiving unit according to claim 1, characterized in that, The outer periphery of the pressure-bearing block is provided with at least one sealing ring along the circumferential direction.

4. The acoustic wave detection and receiving unit according to claim 1, characterized in that, The pressure-bearing block is provided with a connector that penetrates the pressure-bearing block along the axial direction. The end of the connector near the preamplifier circuit board is soldered to the gold finger of the preamplifier circuit board, and the end of the connector away from the preamplifier circuit board protrudes from the surface of the pressure-bearing block.

5. The acoustic wave detection and receiving unit according to claim 4, characterized in that, An insulating layer is provided between the pressure-bearing block and the connector.

6. The acoustic wave detection and receiving unit according to claim 4, characterized in that, It also includes a socket located on the side of the pressure block away from the front circuit board, wherein the female connector in the socket is connected to the corresponding connector.

7. The acoustic wave detection and receiving unit according to claim 6, characterized in that, The socket has a tie post extending along the axial direction on the surface away from the pressure block.

8. The acoustic wave detection and receiving unit according to claim 1, characterized in that, The receiving transducer assembly is fixed to the outer periphery of the frame by a fixing sleeve, and the fixing sleeve is at least partially located between the receiving transducer assembly and the outer periphery of the frame.

9. The acoustic wave detection and receiving unit according to any one of claims 1 to 8, 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 piezoelectric ceramic sheet is in contact with and electrically connected to the negative electrode side surface of another piezoelectric ceramic sheet, so that the two piezoelectric ceramic sheets are connected in series.

10. The acoustic wave detection and receiving unit according to claim 9, characterized in that, The receiving transducer assembly further includes a negative electrode conductive sheet and a positive electrode conductive sheet. The negative electrode conductive sheet is attached to the exposed negative electrode side surface of the two stacked piezoelectric ceramic sheets, and the positive electrode conductive sheet is attached to the exposed positive electrode side surface of the two stacked piezoelectric ceramic sheets.

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