Underground optical fiber sound wave receiver and manufacturing method

Abstract

The invention relates to the field of geophysical logging, and discloses an underground optical fiber sound wave receiver and a manufacturing method thereof.A plurality of sensitization sheets are distributed around a supporting hollow pipe with the supporting hollow pipe as the circle center to form a sensitization cylinder structure, gaps exist between the adjacent sensitization sheets, one ends of a plurality of springs are fixedly arranged around the supporting hollow pipe, and the other ends of the springs are fixedly arranged around the supporting hollow pipe; the weak grating optical fiber is arranged in a surrounding mode in the circumferential direction of the sensitization cylinder structure, the response sensitivity of a sensitization material to sound waves is improved through radial sensitization of an elastic element, the sensitization structure is in a cylindrical design, and the response sensitivity of the sensitization material to the sound waves is improved while the length variation of the sound wave induced optical fiber is evenly increased. The number of components can be remarkably reduced, the system structure is greatly simplified, particularly, the sensitivity of the sensitizing element to sound wave pressure is radially improved by adopting an elastic element, then the length variation of the sound wave induced optical fiber wound on the surface is enhanced, and the sensitivity of the optical fiber for receiving sound wave signals is improved.

Description

Technical Field

[0001] The invention relates to the field of geophysical well logging, and in particular to a downhole optical fiber acoustic wave receiver and a manufacturing method thereof. Background Art

[0002] Acoustic vibration detection is one of the important logging methods for geophysical logging. It is an instrument designed based on acoustic principles. It is a geophysical logging method used to record the acoustic properties of rocks in the underground stratum profile and evaluate the properties of rocks on the well wall by measuring the propagation speed and amplitude of sound waves in the formation. At present, there are two main types of acoustic vibration detection: traditional electrical detection and fiber optic detection. Fiber optic detection has the characteristics of high sensitivity, anti-electromagnetic interference, integrated sensing, passive design, simple structure, high reliability, and easy miniaturization. It supports multiple deployment methods such as point-based, quasi-distributed, and distributed, and can meet the requirements of long-term continuous detection. It has become a hot spot for acoustic detection.

[0003] The existing fiber optic acoustic wave detection mainly includes three types: distributed fiber optic acoustic wave detection system, Fabry-Perot cavity, and fiber Bragg grating. Among them, the distributed fiber optic acoustic wave detection system uses backward Rayleigh scattering to detect the acoustic wave signal at a specific location, which has the characteristics of distributed measurement. However, due to the weak backward Rayleigh scattering signal, the signal sensitivity is low. At the same time, the resolution and signal-to-noise ratio are contradictory and difficult to be compatible at the same time. It has certain limitations for the detection of weak acoustic wave signals. The Fabry-Perot cavity uses the change of external acoustic wave vibration or sound pressure to cause the change of cavity length, thereby changing the change of optical parameters. The environmental acoustic wave / vibration information can be obtained by demodulation, but its cavity is difficult to manufacture and difficult to package. It is difficult to improve the reliability in high temperature and high pressure environments, and it has few engineering applications in the field of well logging. Fiber Bragg gratings utilize gratings with specific reflectivity to enhance the backscattered Rayleigh scattered light signal, thereby increasing the sensitivity of the received signal. However, gratings are prone to degradation at high temperatures, reducing the backscattering intensity of the Rayleigh scattered light. Although the temperature resistance of gratings can be improved by femtosecond direct writing of gratings, there are still problems such as complex sensitivity enhancement structure, many components, low reliability, complex packaging, insufficient temperature and pressure resistance of the system, and difficulty in distributed array detection.

[0004] As oil and gas exploration and development extend towards deep, ultra-deep and complex areas, the level of refinement required for oil and gas reservoir description is further improved, which puts higher demands on the sensitivity, reliability, temperature and pressure resistance, and system reliability and miniaturization of fiber optic acoustic wave detection instruments. Summary of the invention

[0005] In order to overcome the defects of the above-mentioned prior art, the purpose of the present invention is to provide a downhole fiber optic acoustic wave receiver and a manufacturing method to solve the technical problems of the existing downhole fiber optic acoustic wave receivers having complex structure, many parts and components, low reliability, complex packaging, insufficient temperature and pressure resistance of the system, and difficulty in distributed array detection.

[0006] The present invention is achieved through the following technical solutions:

[0007] A downhole fiber optic acoustic wave receiver comprises a supporting hollow circular tube, a plurality of springs, a plurality of sensitizing sheets and a weak grating optical fiber; the plurality of sensitizing sheets are distributed around the supporting hollow tube with the supporting hollow tube as the center to form a sensitizing cylindrical structure, and there are gaps between adjacent sensitizing sheets; one end of the plurality of springs is fixed around the supporting hollow tube, and the other ends are respectively fixed on the plurality of sensitizing sheets; the weak grating optical fiber is arranged around the circumference of the sensitizing cylindrical structure.

[0008] Preferably, the number of the plurality of sensitizing sheets corresponds one to one with the number of the plurality of springs.

[0009] Preferably, the spring is stretched or compressed along the radial direction between the sensitizing sheet and the supporting hollow tube.

[0010] Preferably, a plurality of hollow tube circular grooves are circumferentially arranged on the supporting hollow circular tube, and a plurality of sensitizing thin sheets are respectively provided with thin sheet circular grooves; one end of a plurality of springs is correspondingly embedded in the plurality of hollow tube circular grooves, and the other end is correspondingly embedded in the thin sheet circular grooves on the plurality of sensitizing thin sheets.

[0011] Preferably, the depth of the circular groove of the hollow tube is less than the wall thickness of the supporting hollow tube; the inner diameter of the circular groove of the hollow tube is greater than the outer diameter of the spring; the depth of the circular groove of the thin sheet is less than the thickness of the sensitizing thin sheet, and the inner diameter of the circular groove of the thin sheet is greater than the outer diameter of the spring.

[0012] Furthermore, the spring is fixed in the circular groove of the sheet and the circular groove of the hollow tube by means of high temperature resistant glue.

[0013] Furthermore, the weak grating optical fiber is evenly wound on the outside of the sensitivity enhancement sheet to form an independent sensing receiving section, and the receiving section contains at least two weak gratings.

[0014] A method for manufacturing a downhole optical fiber acoustic wave receiver, used to obtain the downhole optical fiber acoustic wave receiver described above, comprises the following steps:

[0015] S1: Use high temperature glue to fix the spring to the inner side of the sensitivity enhancement sheet, ensuring that the spring is perpendicular to the sensitivity enhancement sheet;

[0016] S2: Connect the sensitizing sheet connected to the spring to the hollow tube so that the other end of the spring is on the outer wall of the supporting hollow tube, and fix it with high-temperature glue to ensure that the spring is perpendicular to the supporting hollow tube;

[0017] S3: Assemble the remaining springs and sensitivity enhancement sheets in sequence, so that a plurality of sensitivity enhancement sheets form a sensitivity enhancement cylindrical structure, and ensure that there are gaps between the sensitivity enhancement sheets;

[0018] S4: Use a fastening device to evenly fasten the upper and lower ends of the sensitivity enhancement sheet, and reduce the gap between the sensitivity enhancement sheets by compressing the spring, but without contacting them;

[0019] S5: Use a winding machine to evenly wind the grating optical fiber around the sensitization sheet with a certain tension, and fix the two ends of the optical fiber with high-temperature glue;

[0020] S6: Remove the fastening devices at the upper and lower ends of the sensitizing sheet, so that the optical fiber bears the pressure transmitted by the spring through the sensitizing sheet.

[0021] Preferably, the weak grating optical fiber is wound on the outside of several sensitizing sheets at a constant tension, wherein the constant tension is 0.1-0.5N.

[0022] Preferably, the weak grating optical fiber is a bend-resistant Bragg grating optical fiber, and the outer surface is coated with a high-temperature resistant coating.

[0023] Compared with the prior art, the present invention has the following beneficial technical effects:

[0024] The present invention provides a downhole optical fiber acoustic wave receiver, wherein a plurality of sensitizing sheets are distributed around a supporting hollow tube with a supporting hollow tube as the center of the circle to form a sensitizing cylindrical structure, and gaps exist between adjacent sensitizing sheets. One end of a plurality of springs is fixed around the supporting hollow tube, and the other ends are respectively fixed on the plurality of sensitizing sheets. A weak grating optical fiber is arranged around the circumference of the sensitizing cylindrical structure, and radial sensitization of an elastic element is adopted to improve the response sensitivity of the sensitizing material to acoustic waves. The sensitizing structure adopts a cylindrical design, which can significantly reduce the number of components while uniformly increasing the acoustic wave induced optical fiber length change, thereby greatly simplifying the system structure. In particular, an elastic element is adopted to radially enhance the sensitivity of the sensitizing element to acoustic wave pressure, thereby enhancing the acoustic wave induced optical fiber length change of the optical fiber wrapped on its surface, and improving the sensitivity of the optical fiber to receiving acoustic wave signals.

[0025] Furthermore, the number of the plurality of sensitizing sheets corresponds to the number of the plurality of springs, and the springs are stretched or compressed along the radial direction between the sensitizing sheets and the supporting hollow tubes to improve the response sensitivity of the sensitizing material to sound waves.

[0026] Furthermore, a plurality of hollow tube circular grooves are circumferentially arranged on the supporting hollow circular tube, and a plurality of sensitizing thin sheets are respectively provided with thin sheet circular grooves; one end of a plurality of springs is correspondingly embedded in the plurality of hollow tube circular grooves, and the other end is correspondingly embedded in the thin sheet circular grooves on the plurality of sensitizing thin sheets, thereby ensuring the stability of the assembly of the springs between the supporting hollow circular tube and the sensitizing thin sheets.

[0027] The present invention also provides a method for improving the sensitivity of the sensitizing element to the sound wave pressure by using an elastic element, thereby enhancing the sound wave induced change in the length of the optical fiber wrapped around the surface of the sensitizing element, and improving the sensitivity of the optical fiber to receive the sound wave signal. By optimizing the design of the sensitizing sheet, the core sensitive structural element of the optical fiber acoustic wave receiver, the change in the length of the acoustic wave induced optical fiber is increased by using a spring circumferential uniform sensitization method, thereby improving the sensitivity of receiving the sound wave signal; using high temperature resistant materials to improve the heat and pressure resistance of the receiver; using anti-bending grating optical fiber can further reduce the diameter of the receiver and improve the miniaturization level of the equipment; using a cylindrical design to improve the adaptability of the receiver in a variety of wellbore environments; fewer components and parts to improve the reliability of the system. The high-sensitivity downhole optical fiber acoustic wave receiver of the present invention has the characteristics of fewer components and parts, simple and reliable structure, easy packaging, high measurement sensitivity, high temperature and high pressure resistance, and support for arbitrary layout. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the structure of the downhole optical fiber acoustic wave receiver in the present invention;

[0029] Figure 2 A top view of the downhole optical fiber acoustic wave receiver structure of the present invention;

[0030] Figure 3 This is the acoustic wave spectrum received by Example 1 of the present invention.

[0031] In the figure: 1-supporting hollow circular tube; 2-spring; 3-weak grating optical fiber; 4-weak grating optical fiber; 5-circular groove of hollow tube; 6-circular groove of thin sheet. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0033] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0034] The purpose of the present invention is to provide a downhole fiber optic acoustic wave receiver and a sensitivity enhancement method to solve the technical problems of existing downhole fiber optic acoustic wave receivers, such as complex structure, many components, low reliability, complex packaging, insufficient temperature and pressure resistance of the system, and difficulty in distributed array detection.

[0035] See also Figure 1 and Figure 2 In one embodiment of the present invention, a downhole fiber optic acoustic wave receiver is provided, comprising a supporting hollow circular tube 1, a plurality of springs 2, a plurality of sensitizing sheets 3 and a weak grating optical fiber 4; the plurality of sensitizing sheets 3 are distributed around the supporting hollow tube 1 to form a sensitizing cylindrical structure with the supporting hollow tube 1 as the center, and there are gaps between adjacent sensitizing sheets 3, one end of the plurality of springs 2 is fixed around the supporting hollow tube 1, and the other end is respectively fixed on the plurality of sensitizing sheets 3, and the weak grating optical fiber 4 is arranged around the circumference of the sensitizing cylindrical structure.

[0036] Specifically, the number of the plurality of sensitivity enhancement sheets 3 corresponds one to one with the number of the plurality of springs 2 .

[0037] Specifically, the spring 2 is stretched or compressed along the radial direction between the sensitizing sheet 3 and the supporting hollow tube 1 .

[0038] Specifically, a plurality of hollow tube circular grooves 5 are circumferentially arranged on the supporting hollow circular tube 1, and a plurality of sensitizing thin sheets 3 are respectively provided with thin sheet circular grooves 6; one end of a plurality of springs 2 is correspondingly embedded in the plurality of hollow tube circular grooves 5, and the other end is correspondingly embedded in the thin sheet circular grooves 6 on the plurality of sensitizing thin sheets 3.

[0039] The depth of the circular groove 5 of the hollow tube is less than the wall thickness of the supporting hollow tube 1 ; the inner diameter of the circular groove 5 of the hollow tube is greater than the outer diameter of the spring 2 .

[0040] Among them, the depth of the circular groove 6 of the thin sheet is less than the thickness of the sensitizing thin sheet 3 , and the inner diameter of the circular groove 6 of the thin sheet is greater than the outer diameter of the spring 2 .

[0041] The spring 2 is fixed in the circular groove 6 of the thin sheet and the circular groove 5 of the hollow tube by means of high temperature resistant glue.

[0042] The supporting hollow circular tube 1 in the present invention is a hollow thin-walled cylindrical structure, and multiple groups of hollow circular grooves 5 are evenly distributed in the circumferential direction of the outer side, which are used to fix multiple groups of springs 2 in the radial direction of the hollow circular tube.

[0043] The springs 2 are multiple groups of high temperature resistant springs, which are evenly placed in the circular groove 5 of the circumferential hollow tube outside the hollow circular tube.

[0044] The sensitizing sheet 3 is a plurality of sheets with specific curvatures, and the plurality of sheets together form an ideal hollow cylinder. The sensitizing sheet 3 has a plurality of evenly distributed sheet circular grooves 6, and the sheet circular grooves 6 on the sensitizing sheet 3 correspond one-to-one with the plurality of hollow tube circular grooves 5 on the outer circumferential direction of the supporting hollow circular tube 1, and are used to fix the plurality of springs 2; the radial hollow tube circular grooves 5 distributed on the outer circumferential direction of the supporting hollow circular tube 1 are the same as the sheet circular grooves 6 on the sensitizing sheet 3 in number, position, and size.

[0045] The material supporting the hollow circular tube 1 and the sensitizing sheet 3 is a high temperature resistant material. The height of the supporting hollow circular tube 1 is not less than the height of the sensitizing sheet 3.

[0046] The weak grating optical fiber 4 is evenly wound on the outside of the sensitivity enhancement sheet 3 to form an independent sensing receiving section, and the receiving section contains at least two weak gratings.

[0047] Several sensitizing sheets 3 are evenly split from large-diameter hollow cylinders to form tiles of equal area with specific curvature.

[0048] In the present invention, before the weak grating optical fiber 4 is wound around the outside of the sensitizing thin sheet 3, a fastening device is used to fasten the sensitizing thin sheet into an approximate cylinder so that the spring 2 is subjected to compression force; after the weak grating optical fiber 4 is wound around the outside of the sensitizing thin sheet 3, the fastening device is removed to ensure that the optical fiber withstands the pressure transmitted by the spring 2 through the sensitizing thin sheet 3.

[0049] The present invention also provides a method for manufacturing a downhole optical fiber acoustic wave receiver, which is used to obtain the downhole optical fiber acoustic wave receiver described above, comprising the following steps:

[0050] S1: Use high temperature glue to fix the spring 2 to the countersunk cylindrical groove 6 on the inner side of the sensitivity enhancement sheet 3, ensuring that the spring 2 is perpendicular to the sensitivity enhancement sheet 3;

[0051] S2: Connect the sensitivity enhancement sheet 3 connected to the spring to the hollow circular tube 1, so that the other end of the spring 2 is in the middle of the countersunk cylindrical groove 5 outside the hollow circular tube 1, and fix it with high-temperature glue to ensure that the spring 2 is perpendicular to the hollow circular tube 1;

[0052] S3: Assemble the remaining springs 2 and the sensitivity enhancement sheets 3 in sequence, so that the sensitivity enhancement sheets 3 form an approximate circle, and ensure that there are gaps between the sensitivity enhancement sheets 3;

[0053] S4: Use a fastening device to evenly fasten the upper and lower ends of the sensitivity enhancement sheet 3, and reduce the gap between the sensitivity enhancement sheets 3 by compressing the spring 2, but without contacting;

[0054] S5: using a winding machine to evenly wind the grating optical fiber 4 around the sensitization sheet 3 with a certain tension, and fixing both ends of the optical fiber with high temperature glue;

[0055] S6: Remove the fastening devices at the upper and lower ends of the sensitizing sheet 3, so that the optical fiber bears the pressure transmitted by the spring 2 through the sensitizing sheet 3.

[0056] Example 1

[0057] A hollow tube with an outer diameter of 30 mm is used as a supporting hollow circular tube, 12 highly sensitive springs are used as sensitivity-enhancing springs, a hollow circular tube with an outer diameter of 50 mm is evenly split into 6 pieces of 60° arc sensitivity-enhancing sheets of equal area, and the supporting hollow circular tube, springs, and sensitivity-enhancing sheets are assembled into a high-sensitivity downhole optical fiber acoustic wave receiver matrix using bolts and nuts. The weak grating optical fiber is wound around the outside of the circumferential sensitivity-enhancing sheet with an outer diameter of 50 mm with a constant tension, and is closely wound for 45 turns to ensure that the middle sections of two weak grating optical fibers separated by an interval of 5000 mm all fall on the closely wound area on the outer surface of the six 60° arc sensitivity-enhancing sheets, thus forming a complete high-sensitivity downhole optical fiber acoustic wave receiver.

[0058] A signal generator is used to connect an acoustic wave transducer through a power amplifier as a transmitting sound source system, one end of a weak grating optical fiber is connected to a demodulation system as a sound wave receiving demodulation system, and the transmitting sound source system and the sound wave receiving demodulation system are placed in a water pool at the same time.

[0059] The signal generator controls the sound source to emit a 9 kHz, 500 ms interval sinusoidal pulse sound wave signal. The sound wave signal causes the change of the length of the optical fiber outside the sensitization sheet, modulating the backscattered Rayleigh light signal. The demodulation system obtains the sound wave signal of the weak grating in the optical fiber by demodulating the phase information of the backscattered Rayleigh light, and then associates the position information to realize the detection of the sound wave signal. The received sound wave signal is as follows: Figure 3 shown.

[0060] In summary, the present invention provides a downhole fiber optic acoustic wave receiver and a manufacturing method thereof, wherein a plurality of sensitizing sheets are distributed around a supporting hollow tube with a supporting hollow tube as the center of the circle to form a sensitizing cylindrical structure, and there are gaps between adjacent sensitizing sheets, one end of a plurality of springs is fixed around the supporting hollow tube, and the other ends are respectively fixed on a plurality of sensitizing sheets, a weak grating optical fiber is arranged around the circumference of the sensitizing cylindrical structure, and radial sensitization of elastic elements is adopted to improve the response sensitivity of the sensitizing material to sound waves, and the sensitizing structure adopts a cylindrical design, which can significantly reduce the number of parts and components while uniformly increasing the change in the length of the optical fiber induced by sound waves, thereby greatly simplifying the system structure, and particularly adopting elastic elements to radially enhance the sensitivity of the sensitizing element to the sound wave pressure, thereby enhancing the change in the length of the optical fiber induced by the sound waves of the optical fiber wrapped around its surface, and improving the sensitivity of the optical fiber to receiving sound wave signals.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A downhole optical fiber acoustic wave receiver, It is characterized in that The invention comprises a supporting hollow circular tube (1), a plurality of springs (2), a plurality of sensitivity enhancing thin sheets (3) and a weak grating optical fiber (4); the plurality of sensitivity enhancing thin sheets (3) are arranged around the supporting hollow tube (1) with the supporting hollow tube (1) as the center of the circle to form a sensitivity enhancing cylindrical structure, and there are gaps between adjacent sensitivity enhancing thin sheets (3); one end of the plurality of springs (2) is fixedly arranged around the supporting hollow tube (1), and the other end is respectively fixed on the plurality of sensitivity enhancing thin sheets (3); and the weak grating optical fiber (4) is arranged around the circumference of the sensitivity enhancing cylindrical structure.

2. A downhole optical fiber acoustic wave receiver according to claim 1, It is characterized in that The number of the plurality of sensitivity enhancement sheets (3) corresponds one to one to the number of the plurality of springs (2).

3. A downhole optical fiber acoustic wave receiver according to claim 1, It is characterized in that The spring (2) is arranged between the sensitivity enhancement sheet (3) and the supporting hollow tube (1) in a stretched or compressed manner along the radial direction.

4. A downhole optical fiber acoustic wave receiver according to claim 1, It is characterized in that The supporting hollow circular tube (1) is provided with a plurality of hollow tube circular grooves (5) in the circumferential direction, and the plurality of sensitivity enhancing thin sheets (3) are provided with thin sheet circular grooves (6) respectively; one end of the plurality of springs (2) is correspondingly embedded in the plurality of hollow tube circular grooves (5), and the other end is correspondingly embedded in the thin sheet circular grooves (6) on the plurality of sensitivity enhancing thin sheets (3).

5. A downhole optical fiber acoustic wave receiver according to claim 4, It is characterized in that The depth of the hollow tube circular groove (5) is less than the wall thickness of the supporting hollow tube (1); the inner diameter of the hollow tube circular groove (5) is greater than the outer diameter of the spring (2); the depth of the thin sheet circular groove (6) is less than the thickness of the sensitizing thin sheet (3), and the inner diameter of the thin sheet circular groove (6) is greater than the outer diameter of the spring (2).

6. A downhole optical fiber acoustic wave receiver according to claim 4, It is characterized in that The spring (2) is fixed in the thin sheet circular groove (6) and the hollow tube circular groove (5) by means of high temperature resistant glue.

7. A downhole optical fiber acoustic wave receiver according to claim 4, It is characterized in that The weak grating optical fiber (4) is evenly wound on the outside of the sensitivity enhancement sheet (3) to form an independent sensing receiving section, and the receiving section contains at least two weak gratings.

8. A method for manufacturing a downhole optical fiber acoustic wave receiver, used to obtain a downhole optical fiber acoustic wave receiver according to any one of claims 1 to 7, It is characterized in that The steps include: S1: Use high temperature glue to fix the spring (2) to the inner side of the sensitivity enhancement sheet (3), ensuring that the spring (2) is perpendicular to the sensitivity enhancement sheet (3); S2: Connect the sensitizing sheet (3) connected to the spring to the hollow circular tube (1), so that the other end of the spring (2) is on the outer wall of the supporting hollow circular tube (1), and fix it with high-temperature glue to ensure that the spring (2) is perpendicular to the supporting hollow circular tube (1); S3: assembling the remaining springs (2) and the sensitivity enhancement sheets (3) in sequence, so that a plurality of the sensitivity enhancement sheets (3) form a sensitivity enhancement cylindrical structure, and ensuring that there are gaps between the sensitivity enhancement sheets (3); S4: Using a fastening device to evenly fasten the upper and lower ends of the sensitivity enhancement sheet (3), and by compressing the spring (2), the gap between the sensitivity enhancement sheets (3) is reduced, but without contact; S5: using a winding machine to evenly wind the grating optical fiber (4) around the sensitizing sheet (3) at a certain tension, and fixing both ends of the optical fiber with high temperature glue; S6: Remove the fastening devices at the upper and lower ends of the sensitivity enhancement sheet (3), so that the optical fiber bears the pressure transmitted by the spring (2) through the sensitivity enhancement sheet (3).

9. A method for manufacturing a downhole optical fiber acoustic wave receiver according to claim 8, It is characterized in that The weak grating optical fiber (4) is wound on the outside of a plurality of sensitizing sheets (3) at a constant tension, wherein the constant tension is 0.1-0.5N.

10. The method for manufacturing a downhole optical fiber acoustic wave receiver according to claim 8, It is characterized in that The weak grating optical fiber (4) is a bend-resistant Bragg grating optical fiber, and the outer surface of the fiber is coated with a high-temperature resistant coating.

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