An underwater acoustic logging device for vibration and noise isolation

Abstract

The present invention discloses a vibration-isolating and sound-isolating underwater acoustic logging device. The device comprises a seismic source, a damper, and a detector. The damper is located between the seismic source and the detector and provides vibration isolation, sound insulation, and acoustic delay. The damper comprises a vibration isolator and a time-delay disc assembly. The time-delay disc assembly comprises a plurality of sequentially stacked delay disc components, each of which has a thin-walled cavity structure filled with air. When detecting underwater formation acoustic wave information, the present invention can reduce the impact of the seismic source on the vibration and acoustic field of the detector, thereby increasing the accuracy of the underwater formation acoustic wave detection signal.

Description

Technical field:

[0001] The present invention relates to the technical field of underwater logging equipment, and in particular to an underwater acoustic wave logging device that is isolating vibration and sound. Background technology:

[0002] Acoustic logging is a logging method that uses the acoustic characteristics of sound waves, such as changes in speed, amplitude, and frequency, when they propagate in different rocks or formations to study the formation profile and determine formation information. Figure 1 As shown, the device excites signals through the source and uses detectors to receive signals transmitted from the well, instrument, and formation. By analyzing the time difference, amplitude, phase and other information of the signal, the various physical parameters in the formation medium are inverted to achieve the purpose of detecting the underground formation structure. The damper is used to reduce the vibration and acoustic amplitude between the source and the detector to improve the accuracy of the acoustic logging signal.

[0003] In actual engineering practice, due to the complexity of its downhole environment, the acoustic logging device has very high requirements for signal recognition and acquisition. Therefore, other factors that affect signal detection need to be considered during actual use. For example, a downhole acoustic dipole transducer designed in Chinese patent application CN201241697Y can be used to make acoustic probes, but the design does not consider the functions of vibration reduction, sound insulation, and reducing the speed of sound propagation, which will affect the accuracy of the actual measured signal. Chinese patent application CN207974807U designs a thin-layer acoustic logging instrument sound insulation body internal structure. This patent places a spacer and rubber block between the transmitting probe and the receiving probe. This structure can only reduce the amplitude of sound propagation, and the effect is very limited. Summary of the invention:

[0004] The technical problem to be solved by the present invention is to provide a vibration-isolating and sound-isolating underwater acoustic logging device to solve the influence of direct vibration and sound waves of equipment in the existing underwater acoustic logging device on the detection signal. This technical solution is a solution that can realize vibration isolation, sound insulation and sound delay to achieve good signal acquisition effect.

[0005] The technical solution of the present invention is to provide a vibration-isolating and sound-isolating underwater acoustic logging device, which includes a seismic source, a damper, and a detector. The damper is located between the seismic source and the detector and plays the role of vibration isolation, sound insulation, and sound delay. The damper is composed of a vibration isolator and a delay disc assembly; wherein, the delay disc assembly is composed of multiple delay disc parts stacked in sequence, and the delay disc parts are thin-walled cavity structures. The thin wall thickness of the delay disc parts is 1-8 mm, and the cavity of the delay disc parts is filled with air.

[0006] Preferably, a connecting post is protruding from the center of the top of the delay disc, and the outer diameter of the connecting post is smaller than the outer diameter of the delay disc. Thus, a variable diameter cross-section is formed between the cavity disc structure of the delay disc and the connecting post. When multiple delay discs are stacked, the delay discs, due to their cavity structures and alternating outer diameters, have variable diameter characteristics that can increase the distance of the sound path in the medium and act as an acoustic-mechanical stopband filter, thereby delaying sound wave signals within a certain frequency band.

[0007] Preferably, the connecting column is a solid structure, and is integrally formed with the delay disc part.

[0008] Preferably, the time-delay disc parts are stacked and assembled by end-to-end threaded connection or welding and then tightly connected to form a time-delay disc assembly.

[0009] Preferably, the outer peripheral surface of the connecting column has an external thread, and correspondingly, the center concave portion below the delay disc part is provided with a thread groove that is threadedly connected to the connecting column, so as to facilitate connection through head and tail threads.

[0010] Preferably, the damper includes a first delay disc assembly and a second delay disc assembly, and a first vibration isolator and a second vibration isolator, wherein the first delay disc assembly is placed between the first vibration isolator and the second vibration isolator, and the second delay disc assembly is placed between the second vibration isolator and the detector.

[0011] Preferably, the first time-delay circular assembly and the second time-delay circular assembly are respectively formed by stacking different numbers of the time-delay circular parts. In other words, the length of the time-delay circular assembly can be adjusted by changing the number of the time-delay circular parts.

[0012] Preferably, the height of the connecting column is greater than the depth of the thread groove.

[0013] Preferably, the seismic source, the vibration isolator, the time delay disk assembly, and the geophone are threadedly connected. To facilitate assembly, the seismic source can be provided with an externally threaded connection portion adapted to the internal threads of the time delay disk assembly, the end portions of the vibration isolator can be provided with external and internal threads adapted to the time delay disk assembly, and similarly, the geophone can be provided with internal threads adapted to the time delay disk components.

[0014] Furthermore, the delay disc part is made of plastic or steel.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] 1. The present invention provides a vibration-isolating and sound-isolating underwater acoustic logging device, wherein the delay disc assembly is composed of a plurality of delay disc parts stacked together, wherein the delay disc parts are thin-walled hollow structures, and the internal medium is air. Due to the huge difference in acoustic impedance between the air and the external water medium, the structure can reduce the transmission level of direct sound waves and achieve the propagation attenuation of sound wave signals within a certain frequency band.

[0017] 2. Since the delay disc part has a cavity structure and the outer diameters of multiple delay disc parts connected in sequence change alternately, its variable diameter feature can increase the distance of the sound path in its medium and act as an acoustic-mechanical stopband filter to achieve delay of the sound wave signal within a certain frequency band.

[0018] 3. The delay disc parts are stacked and assembled by end-to-end thread connection or interference welding and then tightly connected. The structural length of the delay disc assembly can be easily changed by adjusting the number of delay disc parts.

[0019] 4. The time-delay disc assembly consists of two parts, one of which is placed between the seismic source and the vibration isolator. This structural arrangement achieves the vibration isolation effect of a double-layer float valve, effectively reducing the vibration transmission level of the seismic source. Description of the drawings:

[0020] Figure 1 It is a structural diagram of an underwater acoustic logging device in the prior art;

[0021] Figure 2 It is a structural schematic diagram of the underwater acoustic logging device of the present invention;

[0022] Figure 3 This is a schematic diagram of the structure of the time-delay disk component of the underwater acoustic logging device;

[0023] Figure 4 Schematic diagram of the theoretical model of the double-layer float valve structure;

[0024] Figure 5 Schematic diagram of the theoretical model of sound insulation. Specific implementation method:

[0025] The present invention will be further described below with reference to the accompanying drawings:

[0026] like Figure 2As shown, an underwater acoustic logging device includes a source 1, a vibration isolator, a time delay disk assembly, and a detector 4. The time delay disk assembly consists of a first time delay disk assembly 3.1 and a second time delay disk assembly 3.2, and the vibration isolator consists of a first vibration isolator 2.1 and a second vibration isolator 2.2. The first time delay disk assembly 3.1 is placed between the first vibration isolator 2.1 and the second vibration isolator 2.2, and the second time delay disk assembly 3.3 is placed between the second vibration isolator 2.2 and the detector 4. Therefore, it can be obtained. Figure 4 The double-layer floating valve vibration isolation system model can effectively reduce the vibration transmission level of source 1.

[0027] In addition, the source 1 and the detector 4 are respectively provided with threaded interfaces to facilitate their connection and assembly with the vibration isolator and the delay disc assembly.

[0028] The delay disk assembly is composed of multiple delay disk parts 5 stacked in sequence, such as Figure 3 As shown, the time-delay pie component 5 is a thin-walled pie-shaped structure with a cavity in the middle. In this embodiment, its wall thickness is 3mm, and its upper and lower parts are designed with threaded structures. Among them, the center of the top of the time-delay pie component 5 is a convex connecting column 5.1, and the center of the bottom is a concave threaded groove 5.2. The connecting column 5.1 and the threaded groove 5.2 are adapted to facilitate the connection of the end-to-end mechanical structure (which can also be welded and fixed) to form a whole. At the same time, the number of delay pie components can be continuously increased according to actual needs to meet the actual engineering parameter requirements. The connecting column 5.1 above the time-delay pie component 5 is integrally formed with the time-delay pie component 5. The connecting column 5.1 is preferably a solid structure and is located at the center of the pie structure of the time-delay pie component 5, and its circumferential outer diameter is smaller than the outer diameter of the time-delay pie component so that the time-delay pie component constitutes a variable diameter cross section. When multiple time-delay disc components are stacked one after another, the time-delay disc component 5, due to its cavity structure and alternating outer diameter, has a variable diameter feature that can increase the distance of the sound path in its medium and act as an acoustic-mechanical stopband filter, thereby delaying sound wave signals within a certain frequency band. In other words, the time-delay disc component 5 adopts a disc-shaped structure with a variable cross-sectional radius, so the sound path in its solid medium will be greatly increased, and the propagation time of its vibration wave will be extended. At the same time, due to the structural feature of its variable cross-sectional radius, the time-delay disc component 5 acts as an acoustic-mechanical stopband filter, and the propagation of the vibration wave of its earthquake source will be inevitably hindered, thereby delaying sound wave signals within a certain frequency band.

[0029] In this embodiment, the lengths L1 and L2 corresponding to the first delay circular component 3.1 and the second delay circular component 3.2 are different. The number of delay circular components constituting the first delay circular component 3.1 is less than the number of delay circular components constituting the second delay circular component 3.2.

[0030] In principle, the delay disc assembly functions as both sound insulation and acoustic delay. Because the internal cavity of the stacked delay disc components is air, while the acoustic logging device operates in water or mud, the significant difference in acoustic impedance prevents acoustic energy from penetrating the air layer within the delay disc. Furthermore, because the delay disc assembly increases the acoustic path distance and the change in diameter, it increases the propagation time of the vibration sound waves within a certain frequency band, simultaneously acting as an acoustic-mechanical bandstop filter.

[0031] The present invention can reduce the influence of the earthquake source on the vibration and sound field of the detector when detecting underwater stratum acoustic wave information, and increase the accuracy of underwater stratum acoustic wave detection signals.

[0032] The working principle of the present invention is as follows:

[0033] The present invention adopts a method of increasing the sound path in the delay function of the sound wave signal. Figure 3 The structure of the delay disc 5 shown is a thin-walled cavity. When an acoustic wave enters the solid medium at the bottom, its propagation path cannot reach the outlet directly. Instead, it must pass through paths on both sides. This acoustic path significantly increases the propagation time of the vibration wave. Furthermore, due to its variable cross-sectional radius, the delay disc acts as an acoustic-mechanical stopband filter, hindering the propagation of the vibration wave from the source. This delay achieves acoustic signal delay within a certain frequency band.

[0034] The present invention adopts a vibration isolation function similar to Figure 4 The double-layer float valve vibration isolation structure. Figure 2 As shown, the first time delay disk component 3.1 is located between the two vibration isolators, and its function is similar to Figure 4 The double-layer float valve has a central mass m2, while the seismic source 1 is similar to the object m1 being isolated in the double-layer float valve structure. The double-layer float valve structure can achieve twice the vibration isolation of a single isolator. Therefore, this structure effectively reduces the vibration level of the seismic source in the acoustic logging device, thereby minimizing the impact of source 1's vibration on the signal acquisition of geophone 4.

[0035] The present invention adopts a method similar to the Figure 5 The acoustic structure of Figure 3 As shown, the delay disc part 5 is a thin-walled cavity structure, the main medium filled with which is air, and the material of the delay disc part 5 is plastic or steel, and the surrounding medium of the delay disc part is water. Since the acoustic impedance of the air medium in the cavity is very different from the acoustic impedance of the surrounding medium, the sound field energy cannot penetrate the air medium. This is the physical basis for the delay disc component to have sound insulation performance. Therefore, this structure can reduce the transmission level of direct sound waves and achieve the propagation attenuation of sound wave signals within a certain frequency band.

[0036] It should be noted that the seismic source and geophone involved in the present invention are both within the scope of the existing technology and are not the improvement of the present invention, so they will not be further described.

[0037] The above description is only for the preferred embodiment of the present invention, which should not be understood as limiting the claims. Any equivalent structure or equivalent process transformation made by using the description of the present invention is included in the patent protection scope of the present invention.

Claims

1. A vibration-isolating and sound-isolating underwater acoustic logging device, characterized in that: The acoustic logging device includes a seismic source, a damper, and a detector. The damper is located between the seismic source and the detector. The damper is composed of a vibration isolator and a time-delay disk assembly. The time-delay disk assembly is composed of a plurality of time-delay disk parts stacked in sequence. The time-delay disk parts are thin-walled cavity structures with a wall thickness of 1-8 mm. The cavity of the time-delay disk parts is filled with air. A connecting column is also protruded from the center above the delay circular part, and the outer diameter of the connecting column is smaller than the outer diameter of the delay circular part; the connecting column is a solid structure, and is integrally formed with the delay circular part; the delay circular parts are stacked and assembled by end-to-end threaded connection or welding and then tightly connected to form a delay circular assembly; the outer circumferential surface of the connecting column has an external thread, and correspondingly, a threaded groove is concavely provided at the center below the delay circular part, which is threadedly connected to the connecting column; the damper includes a first delay circular assembly and a second delay circular assembly, as well as a first vibration isolator and a second vibration isolator, wherein the first delay circular assembly is placed between the first vibration isolator and the second vibration isolator, and the second delay circular assembly is placed between the second vibration isolator and the detector.

2. The vibration and sound isolation underwater acoustic logging device according to claim 1, characterized in that: The first delay circular cake assembly and the second delay circular cake assembly are respectively formed by stacking different numbers of the delay circular cake parts.

3. The vibration and sound isolation underwater acoustic logging device according to claim 1, characterized in that: The height of the connecting column is greater than the depth of the thread groove.

4. The vibration and sound isolation underwater acoustic logging device according to claim 1, characterized in that: The seismic source, the vibration isolator, the time delay disk assembly and the detector are threadedly connected.

5. The vibration and sound isolation underwater acoustic logging device according to claim 1, characterized in that: The time-delay round cake component is made of plastic or steel.

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