Downhole noise detection method and system

Abstract

The invention discloses an underground noise detection method and system. The method comprises the steps that a target pulse light signal is input into a weak grating optical fiber located in an underground stratum environment through a circulator, the weak grating optical fiber is used for detecting a noise signal in the underground stratum environment, and the weak grating optical fiber comprises a grating array which is etched at equal intervals and low in reflectivity; acquiring a first reflected light signal transmitted according to the weak grating fiber, and acquiring a second reflected light signal output by the circulator according to the target pulsed light; demodulating an interference result of the first reflected light signal and the second reflected light signal to obtain phase information of the first reflected light signal; and determining a noise signal in the underground formation environment according to the phase information. The technical problem that an existing underground noise detection mode is low in reliability and sensitivity is solved.

Description

Technical Field

[0001] The present invention relates to the field of geophysical logging, and in particular, to a method and system for detecting downhole noise. Background Art

[0002] The exploration and development of oil and gas have entered a new stage. The difficulty of discovering oil and gas resources has increased, and the quality of newly discovered oil and gas reserves is low. The developed oilfields are in the "double high" stage of high water cut and high recovery rate, with poor economic efficiency. The exploration and development face key technical bottlenecks. The difficulty of oil and gas exploration and development has increased, and the exploration area has extended to deep / ultra-deep and complex areas. The newly added oil and gas reserves are mainly unconventional oil and gas represented by tight low-permeability, heavy oil, and special lithology reservoirs. The breakthrough of technologies such as the exploration of ultra-deep / complex and hidden oil and gas reservoirs, the enhanced production of old oilfields (such as displacement and fracturing), and the exploitation of unconventional oil and gas has become the key to the stable production and increased reserves, as well as the improvement of the quality and efficiency of oil and gas reservoirs in China.

[0003] With the extension of oil and gas exploration to deep / ultra-deep and complex areas, the refined description of unconventional oil and gas reservoirs has become the key to formulating the development plan of oil and gas reservoirs and enhancing production in the later stage. At present, conventional logging mainly uses deep and shallow laterolog, micro-resistivity, acoustic wave, compensated neutron, density, natural gamma ray, natural potential, etc. Among them, acoustic logging is an instrument designed based on the acoustic principle. By measuring the propagation speed and amplitude of acoustic waves in the formation, it is used to record the rock acoustic properties of the downhole formation profile and evaluate the properties of the wellbore rock. It is one of the important logging methods for geophysical property logging.

[0004] At present, acoustic logging mainly connects the acoustic logging instrument through a cable and lowers it to the designated position in the wellbore through a drum skid, and measures the wellbore during the upward movement of the instrument. However, with the extension of oil and gas exploration to deep / ultra-deep and complex areas, the downhole temperature and pressure are constantly rising, and the existing acoustic logging instruments are difficult to meet the higher wellbore temperature requirements, and the measurement reliability and sensitivity need to be further improved.

[0005] In view of the technical problems of low reliability and sensitivity of the existing detection methods for downhole noise, no effective solution has been proposed yet. Summary of the Invention

[0006] Embodiments of the present invention provide a method and system for detecting downhole noise, so as to at least solve the technical problems of low reliability and sensitivity of the existing downhole noise detection methods.

[0007] According to one aspect of an embodiment of the present invention, a method for detecting downhole noise is provided, including: inputting a target pulsed optical signal into a weak grating optical fiber located in a downhole formation environment through a circulator, where the weak grating optical fiber is used to detect noise signals in the downhole formation environment, and the weak grating optical fiber is provided with a grating array with low reflectivity etched at equal intervals; obtaining a first reflected optical signal transmitted by the weak grating optical fiber, and obtaining a second reflected optical signal output by the circulator according to the target pulsed optical signal; demodulating an interference result of the first reflected optical signal and the second reflected optical signal to obtain phase information corresponding to the interference result; and determining the noise signal in the downhole formation environment according to the phase information.

[0008] According to another aspect of an embodiment of the present invention, a system for detecting downhole noise is further provided, including: a sensing system, which includes a weak grating optical fiber located in a downhole formation environment, where the weak grating optical fiber is used to detect noise signals in the downhole formation environment, and the weak grating optical fiber is provided with a grating array with low reflectivity etched at equal intervals; a demodulation system, which is used to input a target pulsed optical signal into a weak grating optical fiber located in a downhole formation environment through a circulator, where the weak grating optical fiber is used to detect noise signals in the downhole formation environment, and the weak grating optical fiber is provided with a grating array with low reflectivity etched at equal intervals; obtaining a first reflected optical signal transmitted by the weak grating optical fiber, and obtaining a second reflected optical signal output by the circulator according to the target pulsed optical signal; demodulating an interference result of the first reflected optical signal and the second reflected optical signal to obtain phase information corresponding to the interference result; and determining the noise signal in the downhole formation environment according to the phase information.

[0009] According to still another aspect of an embodiment of the present invention, a device for detecting downhole noise is further provided, including: an input unit, which is used to input a target pulsed optical signal into a weak grating optical fiber located in a downhole formation environment through a circulator, where the weak grating optical fiber is used to detect noise signals in the downhole formation environment, and the weak grating optical fiber is provided with a grating array with low reflectivity etched at equal intervals; an obtaining unit, which is used to obtain a first reflected optical signal transmitted by the weak grating optical fiber, and obtain a second reflected optical signal output by the circulator according to the target pulsed optical signal; a demodulation unit, which is used to demodulate an interference result of the first reflected optical signal and the second reflected optical signal to obtain phase information corresponding to the interference result; and a determining unit, which is used to determine the noise signal in the downhole formation environment according to the phase information.

[0010] Optionally, the above-mentioned downhole noise detection device further includes a winding unit, configured to, in response to triggering a target pulsed light, before inputting the target pulsed light into a weak grating optical fiber located in the downhole formation environment through a circulator, wind the weak grating optical fiber into an optical fiber loop, or wind the weak grating optical fiber around a cylindrical substrate to obtain an optical fiber loop, wherein a sensing receiving section is formed in the optical fiber loop, and a plurality of weak gratings are included in the sensing receiving section; a placement unit, configured to place the optical fiber loop in the downhole formation environment.

[0011] Optionally, winding the weak grating optical fiber around a cylindrical substrate to obtain an optical fiber loop includes winding the weak grating optical fiber around a hollow cylindrical substrate to obtain the optical fiber loop.

[0012] Optionally, the above-mentioned demodulation unit includes a first acquisition unit, configured to obtain phase information corresponding to the interference result through a demodulation photodetector, wherein the first reflected optical signal is used to indicate the backward Rayleigh scattered light, and the weak grating optical fiber is used to generate the backward Rayleigh scattered light according to the target pulsed light.

[0013] Optionally, the above-mentioned downhole noise detection device further includes a triggering unit, configured to, in response to triggering a target pulsed light, before inputting the target pulsed light into a weak grating optical fiber located in the downhole formation environment through a circulator, trigger a narrow linewidth laser, wherein the narrow linewidth laser is used to generate an optical signal; a modulation unit, configured to modulate the optical signal according to a semiconductor optical amplifier to obtain a pulsed optical signal; a processing unit, configured to process the reference pulsed optical signal according to an erbium-doped laser to obtain the target pulsed optical signal.

[0014] Optionally, the above-mentioned downhole noise detection device further includes a second acquisition unit, configured to obtain pulsed light parameters and a sampling rate parameter before inputting the target pulsed light into a weak grating optical fiber located in the downhole formation environment through a circulator; a control unit, configured to control the semiconductor optical amplifier and the erbium-doped laser to generate the target pulsed light according to the pulsed light parameters; a third acquisition unit, configured to obtain the first reflected optical signal and the second reflected optical signal according to the sampling rate parameter.

[0015] Optionally, the above-mentioned downhole noise detection device further includes a fourth acquisition unit, configured to obtain the first reflected optical signal and the second reflected optical signal transmitted through a reference optical fiber before demodulating the interference result of the first reflected optical signal and the second reflected optical signal to obtain phase information corresponding to the interference result.

[0016] Optionally, the above-mentioned determination unit further includes a fifth acquisition unit for obtaining the phase information corresponding to the interference result through a demodulation photodetector, a sixth acquisition unit for acquiring the first reflected optical signal and demodulating the first reflected optical signal to obtain the reference phase information of the first reflected optical signal, a first determination unit for determining the signal phase difference according to the phase information and the reference phase information, and a second determination unit for determining the noise signal according to the signal phase difference.

[0017] According to another aspect of the embodiments of the present invention, there is also provided a non-volatile storage medium. The non-volatile storage medium includes a stored program, wherein when the program runs, it controls the device where the non-volatile storage medium is located to execute any one of the above-mentioned downhole noise detection methods.

[0018] According to still another aspect of the embodiments of the present invention, there is also provided a computer device. The computer device includes a processor for running a program, wherein when the program runs, it executes any one of the above-mentioned downhole noise detection methods.

[0019] In the embodiments of the present invention, the adopted downhole noise detection method inputs a target pulsed optical signal into a weak grating optical fiber located in the downhole formation environment through a circulator. Among them, the weak grating optical fiber is used to detect the noise signal in the downhole formation environment, and the weak grating optical fiber includes a grating array with equally spaced low-reflectivity gratings etched thereon; obtain the first reflected optical signal transmitted by the weak grating optical fiber, and obtain the second reflected optical signal output by the circulator according to the target pulse; demodulate the interference result of the first reflected optical signal and the second reflected optical signal to obtain the phase information corresponding to the interference result; determine the noise signal in the downhole formation environment according to the phase information, achieving the detection of long-distance noise, thereby realizing the technical effect of improving the reliability of downhole noise detection, and further solving the technical problems of low reliability and sensitivity of the existing downhole noise detection methods. Description of the Drawings

[0020] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0021] Figure 1 Shows a structural block diagram of a downhole noise detection system for implementing the downhole noise detection method;

[0022] Figure 2 Is a flowchart of a downhole noise detection method provided according to an embodiment of the present invention;

[0023] Figure 3It is a flowchart of another method for detecting downhole noise provided by an embodiment of the present invention;

[0024] Figure 4 It is a schematic diagram of a method for detecting downhole noise provided by an embodiment of the present invention;

[0025] Figure 5 It is a schematic structural diagram of a device for detecting downhole noise provided by an embodiment of the present invention;

[0026] Figure 6 It is a schematic structural diagram of an electronic device provided by an embodiment of the present invention. Detailed implementation manners

[0027] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0028] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order different from those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not necessarily need to be limited to those clearly listed steps or units, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0029] According to an embodiment of the present invention, an embodiment of a method for detecting downhole noise is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that here.

[0030] The method embodiment provided in the first embodiment of the present application can control the system through a terminal device to implement the method for detecting downhole noise. Figure 1 It shows a block diagram of the structure of a downhole noise detection system for implementing the method for detecting downhole noise. As Figure 1As shown in the figure, the downhole noise detection system mainly includes a terminal device 101, a demodulation system 102, a transmission system 103, and a sensing system 104. The downhole noise detection method implemented by the downhole noise detection system shown above specifically includes the following steps: Figure 1 The downhole noise detection method implemented by the downhole noise detection system shown above specifically includes the following steps:

[0031] S1. Input the target pulsed light into a weak grating optical fiber located in the downhole formation environment through a circulator (such as the circulator 110 shown in Figure 1 ). The weak grating optical fiber is used to detect the noise signal in the downhole formation environment, and the weak grating optical fiber includes a grating array with low reflectivity etched at equal intervals.

[0032] S2. Obtain the first reflected light signal transmitted by the weak grating optical fiber through a coupler (such as the coupler 111 shown in Figure 1 ), and obtain the second reflected light signal output by the circulator according to the target pulsed light.

[0033] S3. Demodulate the interference result of the first reflected light signal and the second reflected light signal through a signal processing module (such as the signal processing module 114 shown in Figure 1 ) to obtain the phase information corresponding to the interference result.

[0034] S4. Determine the noise signal in the downhole formation environment according to the phase information.

[0035] It can be understood that the target pulsed light in S1 above is the pulsed light output by an erbium-doped optical amplifier (such as the erbium-doped optical amplifier 109 shown in Figure 1 ). The formation process of the target pulsed light is as follows: The terminal device 101 (such as the terminal device 101 shown in Figure 1 ) controls the signal generator 105 in the demodulation system, and then controls the narrow linewidth laser 106 (which can also be other devices for emitting continuous light such as lasers) to emit laser light. The laser light emitted by the narrow linewidth laser 106 is converted by controlling the semiconductor optical amplifier 108 through the control system 107 to convert the laser light into pulsed light. The pulsed light output by the semiconductor optical amplifier 108 is amplified by the erbium-doped optical amplifier 109 to obtain the target pulsed light in S1 above.

[0036] As shown in Figure 1 , the interference result obtained after the coupler interferes the first reflected light signal and the second reflected light signal is detected by the photodetector 112. At the same time, the photodetector 112 converts the detected optical signal into an electrical signal, and the A / D collector 113 collects the electrical signal output by the photodetector 112 and converts the electrical signal into a digital signal to facilitate the signal processing module 114 to demodulate and analyze the digital signal.

[0037] At the same time, the transmission system 103 can be an optical fiber with a length that meets the preset length, so as to transmit the target pulse light to the sensor system 104. The cylindrical rod included in the sensor system 104 is the weak grating optical fiber obtained by etching the grating optical fiber array with equal spacing and reflectivity. The sounder in the sensor system 104 transmits the sound parameters to the control system 116 through the signal generator 115, so that the control system 116 controls the sounder in the sensor system 104 to emit a sound signal of a preset frequency, and uses this sound signal to imitate the downhole noise, so as to detect the experimental results.

[0038] Through Figure 1 The downhole noise detection system shown implements the downhole noise detection method mentioned above, by inputting the target pulse light signal into a weak grating optical fiber located in the downhole formation environment through a circulator, wherein the weak grating optical fiber is used to detect the noise signal in the downhole formation environment, and the weak grating optical fiber includes a low-reflectivity grating array etched at equal intervals; obtaining a first reflected light signal transmitted according to the weak grating optical fiber, and obtaining a second reflected light signal output by the circulator according to the target pulse light; demodulating the interference result of the first reflected light signal and the second reflected light signal to obtain the phase information corresponding to the interference result; determining the noise signal in the downhole formation environment according to the phase information, thereby achieving the detection of long-distance noise, thereby achieving the technical effect of improving the detection reliability of downhole noise, and further solving the technical problems of low reliability and sensitivity of existing downhole noise detection methods.

[0039] If Figure 1 The two main systems included in the downhole noise detection system shown in are as follows Figure 1 The demodulation system 102 and the sensor system 104 shown in the figure, in the process of implementing the above-mentioned downhole noise detection method, the above-mentioned demodulation system 102 and the sensor system 104 respectively include components and perform specific operations as follows:

[0040] The sensing system 104 includes a weak grating optical fiber located in a well formation environment, wherein the weak grating optical fiber is used to detect noise signals in the downhole formation environment, and the weak grating optical fiber includes a low-reflectivity grating array etched with equal spacing;

[0041] ​​The demodulation system 102 is used to input the target pulsed optical signal into the weak grating optical fiber located in the downhole formation environment through a circulator. The weak grating optical fiber is used to detect the noise signal in the downhole formation environment, and the weak grating optical fiber includes a grating array with low reflectivity etched at equal intervals; obtain the first reflected optical signal transmitted by the weak grating optical fiber, and obtain the second reflected optical signal output by the circulator according to the target pulsed optical signal; demodulate the interference result of the first reflected optical signal and the second reflected optical signal to obtain the phase information corresponding to the interference result; determine the noise signal in the downhole formation environment according to the phase information.

[0042] The above detection method of downhole noise is realized by the above detection system of downhole noise. By etching a weak optical fiber with a lower reflectivity on the optical fiber, the system can significantly increase the number of weak grating arrays, improve the sensing multiplexing ability of the system, meet the requirements of long-distance detection in the downhole, and realize downhole acoustic wave detection.

[0043] The present invention will be described below in conjunction with the preferred implementation steps. Figure 2 It is a flowchart of the detection method of downhole noise provided by an embodiment of the present application. As Figure 2 shown, the method includes the following steps:

[0044] S202, input the target pulsed optical signal into the weak grating optical fiber located in the downhole formation environment through a circulator. The weak grating optical fiber is used to detect the noise signal in the downhole formation environment, and the weak grating optical fiber includes a grating array with low reflectivity etched at equal intervals;

[0045] S204, obtain the first reflected optical signal transmitted by the weak grating optical fiber, and obtain the second reflected optical signal output by the circulator according to the target pulsed optical signal;

[0046] S206, demodulate the interference result of the first reflected optical signal and the second reflected optical signal to obtain the phase information corresponding to the interference result;

[0047] S208, determine the noise signal in the downhole formation environment according to the phase information.

[0048] It should be noted that the pulsed optical signal in S202 is an optical signal with obvious pulse characteristics in time. The characteristics of the pulsed optical signal (such as the above target pulsed optical signal) are that it has a short pulse width and a high peak, so as to judge the specific time period when the phase information of the light changes according to the time difference between the input and output of each beam of pulsed optical signal; the above circulator can be understood as, but not limited to: two transmission paths set for the target pulsed optical signal, one path is used to transmit the pulsed optical signal to the coupler as Figure 1 shown, and the other path is used to transmit the pulsed optical signal to as Figure 1The sensing system 104 shown above; the weak grating optical fiber is provided with a grating array with low reflectivity etched at equal intervals. The weak grating optical fiber can be wound (multiple loops are formed by winding, and the shape of the wound weak grating optical fiber is, for example, a spring shape), and the weak grating optical fiber can also be wound on a fixed substrate to achieve the purpose of fixing the weak grating optical fiber. The noise signal is downhole noise, which includes various noises such as leakage, perforation, fracturing, foreign objects, and deformation existing downhole during downhole operations and non-operations. The downhole formation environment includes various types, such as: groundwater (the water body formed after surface water seeps into the ground), petroleum, well water (the water body extracted from underground rocks through drilling or opening a wellhead), oil-water mixture, gas, etc.

[0049] The second reflected optical signal in S204 is the signal that transmits the target pulsed optical signal to the coupler as shown in Figure 1 in the two transmission paths set by the circulator for the target pulsed optical signal. The second reflected optical signal does not enter the sensing system as shown in Figure 1 and the phase will not change; the first reflected optical signal is the backward Rayleigh scattered optical signal formed by the target pulsed optical signal in the weak grating optical fiber array under the action of downhole noise after transmitting the target pulsed optical signal to the sensing system 104 as shown in Figure 1 in the two transmission paths.

[0050] The interference result in S206 is the result obtained after the first reflected optical signal and the second reflected optical signal interfere. The interference is a phenomenon in which two or more waves meet in space and superimpose or cancel each other to form a new waveform. The interference result can be obtained by coupling the first reflected optical signal and the second reflected optical signal in the coupler 111 as shown in Figure 1 and then interfering the first reflected optical signal and the second reflected optical signal; the demodulation can be understood, but not limited to, determining the phase information corresponding to the interference result according to the interference result. The method of determining the phase information can be: observing the waveform of the interference result to determine the phase information of the interference result, using an oscilloscope to determine the phase information of the interference result, using a spectrum analyzer to determine the phase information of the interference result, etc. It can be understood that for complex signals, the above-mentioned multiple methods can be combined to determine the phase information of the complex signal.

[0051] The step of determining the noise signal in the downhole formation environment according to the phase information in S208 can be, but not limited to: determining the reference phase information of the second reflected optical signal, determining the signal phase difference according to the reference phase information and the phase information in S206, and then determining the downhole noise according to the signal phase difference.

[0052] The downhole noise detection method provided by the embodiments of the present application inputs a target pulsed optical signal into a weak grating optical fiber located in the downhole formation environment through a circulator. Among them, the weak grating optical fiber is used to detect the noise signal in the downhole formation environment, and the weak grating optical fiber includes a grating array with low reflectivity etched at equal intervals; obtain the first reflected optical signal transmitted by the weak grating optical fiber, and obtain the second reflected optical signal output by the circulator according to the target pulsed light; demodulate the interference result of the first reflected optical signal and the second reflected optical signal to obtain the phase information corresponding to the interference result; determine the noise signal in the downhole formation environment according to the phase information, achieving the detection of long-distance noise, thereby realizing the technical effect of improving the detection reliability of downhole noise, and further solving the technical problem of low reliability and sensitivity of the existing downhole noise detection methods.

[0053] As an alternative solution, before inputting the target pulsed light into the weak grating optical fiber located in the downhole formation environment through the circulator in response to triggering the target pulsed light, it further includes:

[0054] S1, winding the weak grating optical fiber into an optical fiber loop, or winding the weak grating optical fiber around a cylindrical substrate to obtain an optical fiber loop, where a sensing receiving section is formed in the optical fiber loop, and the sensing receiving section includes a plurality of weak gratings;

[0055] S2, placing the optical fiber loop in the downhole formation environment.

[0056] It should be noted that the cylindrical substrate in the above S1 can be a substrate with large acoustic wave attenuation, which can avoid using the square groove sound insulation structure in traditional electrical method acoustic logging instruments, greatly simplify the system composition, and improve reliability. The operation in the above S1 can be understood but not limited to determining whether a substrate needs to be used according to the actual situation of the well to be measured. In the case where a substrate does not need to be used, after etching a grating array with low reflectivity at equal intervals on the weak grating optical fiber, the weak grating optical fiber is directly wound into an equal-spacing optical fiber loop, and the specific distance of the equal spacing can be set according to the actual needs during the logging process. In the case where a substrate needs to be used, a target substrate is determined from multiple substrates. After etching a grating array with low reflectivity at equal intervals on the weak grating optical fiber, the weak grating optical fiber is wound around the substrate at equal intervals to obtain an optical fiber loop integrated with the substrate. When winding the weak grating optical fiber on the substrate, the distance between each turn of the weak grating optical fiber also needs to be set according to the actual needs during the logging process.

[0057] The winding spacing of the weak grating optical fiber can be adjusted according to actual applications to meet point-type, quasi-distributed, and distributed layouts. The winding substrate of the weak grating optical fiber can be selected from materials with lower sound propagation velocity, thereby avoiding using the square groove sound insulation structure in traditional electrical method acoustic logging instruments, and greatly simplifying the system composition.

[0058] The downhole noise detection method provided by the embodiment of the present application forms an optical fiber loop by winding a weak grating optical fiber around a cylindrical substrate, or winding the weak grating optical fiber into an optical fiber loop. A sensing and receiving section is formed in the optical fiber loop, and the sensing and receiving section includes a plurality of weak gratings. The optical fiber loop is placed in a downhole liquid environment. By using the weak grating optical fiber to replace the traditional ordinary optical fiber, the backscattered Rayleigh optical signal is enhanced. By winding the weak grating optical fiber into an optical fiber loop or winding it on the surface of a cylindrical substrate, the signal-to-noise ratio of the detected signal (downhole noise) is significantly improved. The winding radius of the optical fiber and the selection of the cylindrical substrate improve the sensitivity enhancement effect of the detected acoustic wave signal. The weak grating optical fiber is arranged in various ways such as point type, array type, and distributed type, realizing point type, quasi-distributed, and distributed detection of weak acoustic wave information in key areas and the entire wellbore downhole.

[0059] As an optional solution, forming the optical fiber loop by winding the weak grating optical fiber around a cylindrical substrate includes: winding the weak grating optical fiber around a hollow cylindrical substrate to obtain an optical fiber loop.

[0060] It should be noted that the winding substrate of the weak grating optical fiber can be solid or hollow, but preferably the above-mentioned hollow cylindrical substrate.

[0061] The downhole noise detection method provided by the embodiment of the present application winds the weak grating optical fiber around a hollow cylindrical substrate to obtain an optical fiber loop, improving the signal-to-noise ratio of the detected signal.

[0062] As an optional solution, demodulating the interference result of the first reflected optical signal and the second reflected optical signal to obtain the phase information corresponding to the interference result includes: obtaining the phase information corresponding to the interference result through a demodulation photodetector, where the first reflected optical signal is used to indicate the backscattered Rayleigh optical signal, and the weak grating optical fiber is used to generate the backscattered Rayleigh optical signal according to the target pulsed light.

[0063] It should be noted that the operation of obtaining the phase information corresponding to the interference result through the demodulation photodetector can be, but is not limited to, understood as detecting the interference result (a signal of a new waveform) obtained after the first reflected optical signal and the second reflected optical signal interfere through the optical detector 112 (which can also be a photodetector) as shown in Figure 1 After the interference result is converted into an electrical signal by the optical detector 112, the electrical signal is transmitted to the A / D collector 113. The A / D collector 113 converts the electrical signal into a digital signal and transmits the digital signal to the signal processing module 114. The signal processing module determines the phase information corresponding to the digital signal by demodulating the digital signal.

[0064] The downhole noise detection method provided by the embodiments of the present application obtains the phase information corresponding to the interference result by demodulating a photodetector. Among them, the first reflected light signal is used to indicate the backward Rayleigh scattered light, and the weak grating optical fiber is used to generate the backward Rayleigh scattered light according to the target pulsed light. The position and noise intensity of the downhole noise are determined according to the time of the light intensity change and the phase information of the new signal after the light intensity change, so as to achieve long-distance detection. By means of the light intensity change, the downhole noise signal at a long distance can also be detected, and the signal will not be significantly attenuated, improving the accuracy of long-distance downhole detection.

[0065] As an optional solution, before the target pulsed light is input into the weak grating optical fiber located in the downhole formation environment through the circulator in response to the triggering of the target pulsed light, it further includes:

[0066] S1, trigger a narrow linewidth laser, where the narrow linewidth laser is used to emit an optical signal;

[0067] S2, modulate the emitted optical signal according to a semiconductor optical amplifier to obtain a reference pulsed optical signal;

[0068] S3, process the reference pulsed optical signal according to an erbium-doped laser to obtain a target pulsed optical signal.

[0069] It should be noted that the above erbium-doped laser is used to perform signal amplification processing on the reference pulsed optical signal to obtain a target pulsed optical signal.

[0070] The downhole noise detection method provided by the embodiments of the present application, before the target pulsed light is input into the weak grating optical fiber located in the downhole formation environment through the circulator in response to the triggering of the target pulsed light, triggers a narrow linewidth laser, where the narrow linewidth laser is used to generate an optical signal; modulates the emitted optical signal according to a semiconductor optical amplifier to obtain a reference pulsed optical signal, and modulates the continuous laser signal into reference pulsed optical signals corresponding to multiple time differences respectively; processes the reference pulsed optical signal according to an erbium-doped laser to obtain a target pulsed optical signal, realizing the amplification processing of the pulsed optical signal, avoiding the small change in the backward Rayleigh scattered optical signal reflected due to the small signal intensity, which is not convenient for demodulating the interference result between the backward Rayleigh scattered optical signal (the above first reference optical signal) and the second reference optical signal, and improving the reliability of the downhole noise detection method.

[0071] As an optional solution, before the target pulsed light is input into the weak grating optical fiber located in the downhole formation environment through the circulator, it further includes:

[0072] S1, obtain the pulsed light parameter and the sampling rate parameter;

[0073] S2. Control a semiconductor optical amplifier and an erbium-doped laser to generate a target pulsed light according to the pulsed light parameters;

[0074] S3. Obtain a first reflected light signal and a second reflected light signal according to the sampling rate parameters.

[0075] It should be noted that the above-mentioned pulsed light parameters include pulse amplitude, pulse leading edge, pulse trailing edge, pulse width, pulse period, and pulse frequency, etc. The above-mentioned sampling rate parameters include: sampling period (the time length for sampling a signal at a certain time interval), sampling rate (the number of signals collected per second), resolution (the value range of the digital signal), quantization bits (the number of bits used for the binary representation of each sampling point of the digital signal when converting an analog signal into a digital signal), and filter (added after the sampler to filter out unnecessary signal components to achieve consistent clutter and improve the signal-to-noise ratio).

[0076] The downhole noise detection method provided by the embodiments of the present application, before inputting the target pulsed light into the weak grating optical fiber located in the downhole formation environment through an optical circulator, obtains the pulsed light parameters and the sampling rate parameters; controls a semiconductor optical amplifier and an erbium-doped laser to generate a target pulsed light according to the pulsed light parameters; obtains a first reflected light signal and a second reflected light signal according to the sampling rate parameters. After pre-setting the pulsed light parameters and the sampling rate parameters, start to control the generation of laser light, and obtain the first reflected light signal and the second reflected light signal, which is convenient for accurately demodulating the interference result according to the fixed pulsed light parameters and sampling rate parameters later, so as to accurately determine the phase information of the interference result and improve the accuracy of the phase information.

[0077] The following Figure 1 、 Figures 3 to 4 will be used to explain in detail the above-mentioned downhole noise detection method of the present application:

[0078] S302. Lay out the weak grating optical fiber;

[0079] The above-mentioned method of laying out the weak grating optical fiber includes: winding the weak grating optical fiber into an optical fiber loop with uniform tension or winding it on a cylindrical substrate to form sensing receiving segments. Among them, the above-mentioned optical fiber loop includes at least two weak gratings to ensure an independent weak grating sensing receiving segment. The spacing between the above-mentioned optical fiber loops can be adjusted according to the actual situation to meet point-type, quasi-distributed, and distributed layouts; winding the weak grating optical fiber periodically to form a weak grating optical fiber sensing array.

[0080] S302-1. Wind the optical fiber loop;

[0081] The above-mentioned winding of the optical fiber loop includes directly winding the weak grating optical fiber into an optical fiber loop or winding the weak grating optical fiber on the surface of a hollow cylindrical substrate;

[0082] S302-2, placed in the underground formation environment;

[0083] The operation in the above S302-2 can be understood as, but not limited to: after the above S302-1 to S302-2, the obtained optical fiber ring is placed in the underground formation environment.

[0084] S302-3, actual fiber optic layout;

[0085] It should be noted that the operation in the above S302-3 can be understood as, but not limited to, the process of laying out the transmission system, such as selecting optical fibers in the transmission system, and the optical fibers in the transmission system can be ordinary optical fibers.

[0086] S304, connecting the weak grating fiber array and the demodulation system through optical fiber;

[0087] It should be noted that the operations in the above S302 to S304 can be understood as, but not limited to: arranging weak grating optical fibers, winding the weak grating optical fibers on the surface of the hollow cylindrical substrate, and then passing through the optical fiber transmission section (such as Figure 1 The transmission system 103 shown in the figure, the optical fiber used in the transmission section can be a common optical fiber or a weak grating optical fiber) to connect the weak grating optical fiber in the downhole formation environment with the circulator.

[0088] S306, turn on the demodulation system, set parameters, and generate enhanced backscattered Rayleigh light in the weak grating fiber;

[0089] S308, after the backscattered Rayleigh light passes through interference, the signal detected by the photoelectric detector enters the signal processing module;

[0090] S310, the signal processing module demodulates the sound wave signal.

[0091] It should be noted that the steps from S306 to S310 above can be understood as, but not limited to: opening the Figure 1 The demodulation system 102 (also called demodulation control system) shown in sets the pulse light parameters and sampling parameters. The laser generated by the narrow line width laser is modulated by the pulse modulator. The modulated pulse light enters the weak grating optical fiber through the circulator. Under the action of the downhole noise, it is reflected by the weak grating to generate enhanced back Rayleigh scattered light. The Rayleigh scattered light returns to through the circulator. Figure 1 The coupler 111 shown, after the Rayleigh scattered light and the second reflected light signal are coupled and interfered in the coupler 111, the light signal intensity changes, and an interference result is obtained. The light detector 112 converts the detected interference result into an electrical signal and transmits it to the A / D collector 113. The A / D collector 113 converts the electrical signal into a digital signal and transmits the digital signal to the signal processing module 114 for signal demodulation, thereby obtaining the final sound wave signal, thereby achieving the effect of sound wave detection.​​

[0092] The effect of the downhole noise detection method implemented through the above process is as Figure 4 shown ( Figure 4 In the (a) figure of Figure 4 and the (b) figure of Figure 4 the abscissa is time, with the unit of millisecond, and the ordinate is the signal intensity of the detected acoustic wave signal): As shown in the (a) figure of Figure 4 it shows the effect of detecting downhole noise at a short distance, and as shown in the (b) figure of Figure 4 it shows the effect of detecting downhole noise at a long distance. It can be seen from the (a) figure to the (b) figure of

[0093] that even for long-distance detection, the above downhole noise detection method can still accurately detect downhole noise. Figure 1 Through the above embodiments of the present application, by etching an array of weak gratings with a specific reflectivity in an ordinary optical fiber, the intensity of the backward Rayleigh scattered light is increased, and the intensity of the optical signal change caused by the change in the fiber length due to downhole noise vibration is enhanced, significantly improving the sensitivity of the system to detect downhole acoustic wave signals. The downhole noise detection method implemented through the downhole noise detection system as shown in

[0094] is not only simple and reliable in structure, high in measurement sensitivity, supports arbitrary layout, but also meets the requirements of downhole long-distance detection.

[0095] As an optional solution, before demodulating the interference result of the first reflected optical signal and the second reflected optical signal to obtain the phase information corresponding to the interference result, it further includes: obtaining the first reflected optical signal and the second reflected optical signal transmitted through the reference optical fiber. Figure 1 It should be noted that the above reference optical fiber includes a first reference optical fiber and a second reference optical fiber. The first reference optical fiber is used to input the above target pulsed optical signal into the coupler 111 through the circulator 110 as shown in Figure 1 and determine the target pulsed optical signal input to the coupler 111 through this path as the reference optical signal (i.e., the above second reflected optical signal). The second reference optical fiber is the optical fiber on the transmission system 103 as shown in Figure 1 The second reference optical fiber is used to transmit the backward Rayleigh scattered light output by the sensing system to the coupler 111 as shown in Figure 1 After the second reflected optical signal output by the first reference optical fiber and the first reflected optical signal output by the second reference optical fiber are coupled in the coupler 111, interference occurs between the first reference optical signal and the second reference optical signal, thereby generating a change in optical intensity. Then, the interference result after the interference of the first reference optical signal and the second reference optical signal is detected by the optical detector as shown in

[0096] The downhole noise detection method provided by the embodiments of the present application obtains a first reflected light signal and a second reflected light signal transmitted through a reference optical fiber, thereby retaining the second reflected light signal unaffected by downhole noise. At the same time, after obtaining the backward Rayleigh scattered light (the above-mentioned first reflected light signal) generated under the influence of downhole noise, the backward Rayleigh scattered light signal and the above-mentioned second reflected light signal are coupled and interfered through a coupler to obtain an interference result, and the interference result is demodulated to accurately determine the phase information corresponding to the interference result, and then the position and intensity of the downhole noise are determined, improving the accuracy of the downhole noise detection method.

[0097] As an optional solution, determining the noise signal in the downhole liquid environment according to the phase information includes:

[0098] S1, obtaining the phase information corresponding to the interference result through a demodulation photodetector;

[0099] S2, obtaining the second reflected light signal and demodulating the second reflected light signal to obtain the reference phase information of the second reflected light signal;

[0100] S3, determining the signal phase difference according to the phase information and the reference phase information;

[0101] S4, determining the noise signal according to the signal phase difference.

[0102] It should be noted that determining the noise signal according to the signal phase difference includes determining the position and signal intensity of the noise signal; determining the position of the noise signal according to the signal phase difference includes: determining the position of the noise signal according to the magnitude and time difference of the phase difference. Determining the signal intensity of the noise signal according to the signal phase difference includes: calculating the variance of the signal phase difference (performing statistical analysis on the sequence of the signal phase difference and calculating its variance, and the variance is used to indicate the degree of dispersion of the signal phase difference); converting the variance of the signal phase difference into decibel units.

[0103] The downhole noise detection method provided by the embodiments of the present application obtains the phase information corresponding to the interference result through a demodulation photodetector; obtains the first reflected light signal and demodulates the first reflected light signal to obtain the reference phase information of the first reflected light signal; determines the signal phase difference according to the phase information and the reference phase information; determines the noise signal according to the signal phase difference, thereby converting the downhole noise into a change in optical phase, thereby determining the phase noise of the downhole noise, and then accurately determining the position and signal intensity of the downhole noise according to the phase noise, which not only ensures the measurement accuracy of the downhole noise, but also does not require the use of complex measuring instruments, simplifies the downhole noise detection system, and saves the cost of complex measuring instruments.

[0104] The following uses two specific embodiments to conduct a detailed test and description of the above-mentioned downhole noise detection method:

[0105] Embodiment 1

[0106] S1. Wind the weak grating optical fiber around a substrate rod with an outer diameter of 82 mm at a constant tension, closely wind 25 turns, and ensure that the middle sections of two weak grating optical fibers with a spacing of 5000 mm all fall within the closely wound area on the outer surface of the substrate;

[0107] S2. Place the detection rod wound with the weak grating optical fiber in a pool and submerge it completely; the other end of the weak grating optical fiber is connected to a demodulation system, and the demodulation system is connected to the computer control system through a data line;

[0108] S3. Place a sound source system 1500 mm away from the detection rod in the pool, and control the sound source to emit a sine pulse acoustic signal (simulating downhole noise) at 9 kHz with a 500 ms interval through a signal generator;

[0109] S4. Turn on the demodulation control system, set the pulse light parameters and sampling parameters. The laser generated by the laser is modulated by a pulse modulator, amplified by an erbium-doped amplifier, and then enters the weak grating optical fiber array through a circulator. The pulsed light in the weak grating optical fiber array generates enhanced backward Rayleigh scattered light after being reflected by the weak grating;

[0110] S5. The backward Rayleigh scattered light enters the photodetector after interference by the circulator and coupler, is converted into an electrical signal, and then enters the signal processing module;

[0111] S6. The signal processing module obtains the acoustic signal of the weak grating in the optical fiber by demodulating the phase information of the backward Rayleigh scattered light, and then correlates the position information to realize the detection of the acoustic signal. The received acoustic signal is as Figure 4 shown.

[0112] Embodiment 2

[0113] S1. Wind the weak grating optical fiber around a substrate rod with an outer diameter of 82 mm at a constant tension, closely wind 25 turns, and ensure that the middle sections of two weak grating optical fibers with a spacing of 5000 mm all fall within the closely wound area on the outer surface of the substrate;

[0114] S2. Place the detection rod wound with the weak grating optical fiber in a pool and submerge it completely; the other end of the weak grating optical fiber is connected to a 7000 m ordinary single-mode optical fiber, and the other end of the single-mode optical fiber is connected to a demodulation system. The demodulation system is connected to the computer control system through a data line. All optical fiber connections adopt optical fiber fusion splicing;

[0115] S3. Place a sound source system 1500 mm away from the detection rod in the pool, and control the sound source to emit a sine pulse acoustic signal at 9 kHz with a 500 ms interval through a signal generator;

[0116] In S4, turn on the demodulation control system. After setting the pulse light parameters and sampling parameters, the laser generated by the laser passes through the pulse modulator for modulation, is amplified by the erbium-doped amplifier, and then enters the weak grating fiber array through the circulator. The pulsed light in the weak grating fiber array generates enhanced backward Rayleigh scattering light after being reflected by the weak grating.

[0117] In S5, the backward Rayleigh scattering light enters the photodetector after interference by the circulator and the coupler, is converted into an electrical signal, and then enters the signal processing module.

[0118] In S6, the signal processing module obtains the acoustic wave signal of the weak grating in the optical fiber by demodulating the phase information of the backward Rayleigh scattering light, and then correlates the position information to realize the detection of the acoustic wave signal. The received acoustic wave signal is as Figure 4 shown.

[0119] It can be seen from the actual test results of the above-mentioned detection method of downhole noise in Embodiment 1 and Embodiment 2 of the present application by simulating downhole noise that the above-mentioned detection method of downhole noise in the present application can accurately detect downhole noise whether it is the detection of downhole noise for short-distance transmission or long-distance transmission, solving the problem of low reliability and accuracy of the existing detection method of downhole noise due to the inability to detect the downhole noise detection signal for long-distance transmission. At the same time, the present application enhances the backward Rayleigh scattering light through the weak grating, improves the signal-to-noise ratio of the detected acoustic wave signal, and significantly improves the sensitivity of the downhole acoustic wave monitoring system.

[0120] The above is only a detailed description of the specific embodiments of the present invention, rather than a limitation of the present invention. Various substitutions, deformations, and improvements made by those skilled in the relevant technical fields without departing from the principles and scope of the present invention are included in the protection scope of the present invention.

[0121] It should be noted that for the foregoing method embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the present invention is not limited by the described action sequence, because according to the present invention, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0122] Through the description of the above embodiments, those skilled in the art can clearly understand that the method for detecting downhole noise according to the above embodiments can be implemented by means of software plus a necessary general hardware platform. Of course, it can also be implemented by hardware, but in many cases, the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions for causing a terminal device (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods described in various embodiments of the present invention.

[0123] According to an embodiment of the present invention, there is also provided a downhole noise detection device for implementing the above-mentioned downhole noise detection method. Figure 5 FIG. is a structural block diagram of the downhole noise detection device provided according to an embodiment of the present invention. As Figure 5 shown, the downhole noise detection device includes: an input unit 502, an acquisition unit 504, a demodulation unit 506, and a determination unit 508. As Figure 5 shown, in the process of the downhole noise detection device implementing the above-mentioned downhole noise detection method, the functions played by each unit are specifically as follows:

[0124] The input unit 502 is configured to input a target pulsed optical signal into a weak grating optical fiber located in the downhole formation environment through a circulator. Among them, the weak grating optical fiber is used to detect noise signals in the downhole liquid environment, and the weak grating optical fiber includes a grating array with equally spaced etched low reflectivity.

[0125] The acquisition unit 504 is configured to acquire a first reflected optical signal transmitted by the weak grating optical fiber and acquire a second reflected optical signal output by the circulator according to the target pulsed optical signal.

[0126] The demodulation unit 506 is configured to demodulate the interference result of the first reflected optical signal and the second reflected optical signal to obtain the phase information corresponding to the interference result.

[0127] The determination unit 508 is configured to determine the noise signal in the downhole formation environment according to the phase information.

[0128] It should be noted here that the above input unit 502, acquisition unit 504, demodulation unit 506, and determination unit 508 respectively correspond to steps S202 to S208 in the embodiment. The examples and application scenarios implemented by multiple modules and the corresponding steps are the same, but are not limited to the content disclosed in the above embodiments.

[0129] Embodiments of the present invention can provide a computer device. Optionally, in this embodiment, the above computer device can be at least one network device among multiple network devices in a computer network. The computer device includes a memory and a processor.

[0130] Among them, the memory can be used to store software programs and modules, such as program instructions / modules corresponding to the detection method and system of downhole noise in the embodiments of the present invention. The processor executes various functional applications and data processing by running the software programs and modules stored in the memory, that is, implements the above-mentioned detection method of downhole noise. The memory can include a high-speed random access memory, and can also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memories. In some instances, the memory can further include a memory remotely set relative to the processor, and these remote memories can be connected to the computer terminal through a network. Examples of the above network include but are not limited to the Internet, enterprise intranet, local area network, mobile communication network, and their combinations.

[0131] The processor can call the information and application programs stored in the memory through a transmission device to control each component in the downhole noise detection system to implement the following steps: input a target pulsed optical signal into a weak grating optical fiber located in the downhole formation environment through a circulator, where the weak grating optical fiber is used to detect noise signals in the downhole formation environment, and the weak grating optical fiber includes a grating array with equally spaced low-reflectivity gratings etched thereon; obtain a first reflected optical signal transmitted by the weak grating optical fiber, and obtain a second reflected optical signal output by the circulator according to the target pulse light; demodulate the interference result of the first reflected optical signal and the second reflected optical signal to obtain the phase information corresponding to the interference result; determine the noise signal in the downhole formation environment according to the phase information.

[0132] Those of ordinary skill in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by a program instructing relevant hardware devices controlled by a terminal device. The program can be stored in a non-volatile storage medium, and the storage medium can include: flash drive, read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disc, etc.

[0133] Embodiments of the present invention also provide a non-volatile storage medium. Optionally, in this embodiment, the above non-volatile storage medium can be used to save data information related to the detection method of downhole noise provided in the above embodiments, such as data information related to the first reference optical signal and the second reference optical signal respectively, data information related to the above interference result, and preset pulsed light parameters and sampling rate parameters.

[0134] Optionally, in this embodiment, the non-volatile storage medium may be located in any one of the computer terminals in the computer terminal group in the computer network, or in any one of the mobile terminals in the mobile terminal group.

[0135] Optionally, in this embodiment, the non-volatile storage medium is configured to store program codes for controlling each component in the detection system for downhole noise to perform the following steps: input the target pulsed optical signal into the weak grating optical fiber located in the downhole formation environment through the circulator, where the weak grating optical fiber is used to detect the noise signal in the downhole formation environment, and the weak grating optical fiber includes a grating array with equally spaced etched low-reflectivity gratings; obtain the first reflected optical signal transmitted by the weak grating optical fiber, and obtain the second reflected optical signal output by the circulator according to the target pulse; demodulate the interference result of the first reflected optical signal and the second reflected optical signal to obtain the phase information corresponding to the interference result; determine the noise signal in the downhole formation environment according to the phase information.

[0136] The embodiment of the present invention also provides an electronic device for implementing the above-mentioned method for detecting downhole noise. The electronic device may be a Figure 6 terminal device or a server as shown. In this embodiment, this electronic device is taken as an example for illustration. As Figure 6 shown, the electronic device includes a memory 602 and a processor 604. A computer program is stored in the memory 602, and the memory 602 may but is not limited to include the input unit 502, the acquisition unit 504, the demodulation unit 506, and the determination unit 508 in the above-mentioned detection device for downhole noise. The processor 604 is configured to execute the above-mentioned method for detecting downhole noise through the computer program.

[0137] Optionally, those of ordinary skill in the art can understand that Figure 6 the structure shown is only schematic. The electronic device may also be a smart phone (such as an Android phone, an iOS phone, etc.), a tablet computer, a palm computer, and a mobile Internet device (Mobile Internet Devices, MID), a PAD and other terminal devices. Figure 6 It does not limit the structure of the above-mentioned electronic device. For example, the electronic device may further include more or fewer components (such as a network interface, etc.) than those shown in Figure 6 , or have a different configuration from that shown in Figure 6 .

[0138] Among them, the memory 602 can be used to store software programs and modules, such as the program instructions / modules corresponding to the downhole noise detection method and system in the embodiments of the present application. The processor 604 executes various functional applications and data processing by running the software programs and modules stored in the memory 602, that is, implements the above-mentioned downhole noise detection method. The memory 602 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memories. In some instances, the memory 602 may further include a memory remotely disposed relative to the processor 604, and these remote memories can be connected to the terminal through a network. Examples of the above network include but are not limited to the Internet, enterprise intranet, local area network, mobile communication network, and combinations thereof.

[0139] Optionally, the above electronic device further includes a transmission device 606, and the transmission device 606 is used to receive or send data via a network. Specific examples of the above network may include a wired network and a wireless network. In one instance, the transmission device 606 includes a network adapter (Network Interface Controller, NIC), which can be connected to other network devices and routers through a network cable, thereby enabling communication with the Internet or a local area network. In one instance, the transmission device 606 is a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0140] In addition, the above electronic device further includes: a display 608, which is used to display the above first reference optical signal, second reference optical signal, and interference result; and a connection bus 610, which is used to connect each module component in the above electronic device.

[0141] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0142] In the above embodiments of the present invention, the descriptions of each embodiment have their own focuses. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0143] In several embodiments provided by the present application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only illustrative. For example, the division of the units can be a logical function division. In actual implementation, there can be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection to each other can be through some interfaces. The indirect coupling or communication connection of units or modules can be in an electrical or other form.

[0144] The unit described as a separation component may or may not be physically separated. The component shown as a unit may or may not be a physical unit, that is, it may be located in one place or may be distributed to multiple units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0145] In addition, each functional unit in various embodiments of the present invention may be integrated in a processing unit, or each unit may exist physically alone, or two or more units may be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0146] If the above-mentioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a non-volatile storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to enable a computer device (which can be a personal computer, a server or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes: USB flash drive, read-only memory (ROM), random access memory (RAM), mobile hard disk, magnetic disk or optical disc and other various media that can store program codes.

[0147] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for detecting underground noise, characterized in that: include: Inputting the target pulse light signal into a weak grating optical fiber located in a downhole formation environment through a circulator, wherein the weak grating optical fiber is used to detect noise signals in the downhole formation environment, and the weak grating optical fiber includes a low-reflectivity grating array etched at equal intervals; Acquire a first reflected light signal transmitted by a weak grating optical fiber, and acquire a second reflected light signal output by the circulator according to the target pulse light; Demodulating an interference result of the first reflected light signal and the second reflected light signal to obtain phase information corresponding to the interference result; The noise signal within the downhole formation environment is determined based on the phase information.

2. The method according to claim 1, characterized in that In response to triggering the target pulse light, the target pulse light is input into the weak grating optical fiber located in the downhole formation environment through a circulator, and further includes: Winding the weak grating optical fiber into an optical fiber ring, or winding the weak grating optical fiber on a cylindrical substrate to obtain an optical fiber ring, wherein a sensing receiving section is formed in the optical fiber ring, and the sensing receiving section includes a plurality of weak gratings; The optical fiber ring is placed in the downhole formation environment.

3. The method according to claim 2, characterized in that The step of winding the weak grating optical fiber on a cylindrical substrate to obtain an optical fiber ring comprises: The weak grating optical fiber is wound on a hollow cylindrical substrate to obtain the optical fiber ring.

4. The method according to claim 2, characterized in that: The demodulating the interference result of the first reflected light signal and the second reflected light signal to obtain phase information corresponding to the interference result includes: Phase information corresponding to the interference result is obtained by demodulating a photodetector, wherein the first reflected light signal is used to indicate the backscattered Rayleigh light, and the weak grating optical fiber is used to generate the backscattered Rayleigh light according to the target pulse light.

5. The method according to claim 1, characterized in that In response to triggering the target pulse light, before the target pulse light is input into the weak grating optical fiber located in the downhole formation environment through the circulator, the method further includes: triggering a narrow linewidth laser, wherein the narrow linewidth laser is used to generate an optical signal; Modulating the emission optical signal according to the semiconductor optical amplifier to obtain a reference pulse optical signal; The reference pulse light signal is processed according to the erbium-doped laser to obtain the target pulse light signal.

6. The method according to claim 5, characterized in that Before the target pulse light is input into the weak grating optical fiber located in the downhole formation environment through the circulator, the method further includes: Obtain pulse light parameters and sampling rate parameters; Controlling the semiconductor optical amplifier and the erbium-doped laser to generate the target pulse light according to the pulse light parameters; The first reflected light signal and the second reflected light signal are acquired according to the sampling rate parameter.

7. The method according to claim 1, characterized in that Before demodulating the interference result of the first reflected light signal and the second reflected light signal to obtain phase information corresponding to the interference result, the method further includes: A second reflected light signal transmitted through the first reflected light signal and the reference optical fiber is acquired.

8. The method according to claim 1, characterized in that Determining the noise signal in the downhole formation environment according to the phase information includes: Obtaining phase information corresponding to the interference result by demodulating the photoelectric detector; Acquire the first reflected light signal, and demodulate the first reflected light signal to obtain reference phase information of the first reflected light signal; Determine a signal phase difference according to the phase information and the reference phase information; The noise signal is determined according to the signal phase difference.

9. A downhole noise detection system, characterized in that: include: A sensing system, wherein the sensing system includes a weak grating optical fiber located in a downhole formation environment, wherein the weak grating optical fiber is used to detect noise signals in the downhole formation environment, and the weak grating optical fiber includes a low-reflectivity grating array etched with equal spacing; A demodulation system, wherein the demodulation system is used to input a target pulse light signal into a weak grating optical fiber located in a downhole formation environment through a circulator, wherein the weak grating optical fiber is used to detect noise signals in the downhole formation environment, and the weak grating optical fiber includes a low-reflectivity grating array etched at equal intervals; obtain a first reflected light signal transmitted according to the weak grating optical fiber, and obtain a second reflected light signal output by the circulator according to the target pulse light; demodulate the interference result of the first reflected light signal and the second reflected light signal to obtain phase information corresponding to the interference result; and determine the noise signal in the downhole formation environment according to the phase information.

10. A device for detecting underground noise, characterized in that: include: An input unit, used for inputting a target pulse optical signal into a weak grating optical fiber located in a downhole formation environment through a circulator, wherein the weak grating optical fiber is used for detecting noise signals in the downhole formation environment, and the weak grating optical fiber includes a low-reflectivity grating array etched at equal intervals; an acquisition unit, used for acquiring a first reflected light signal transmitted by the weak grating optical fiber, and acquiring a second reflected light signal output by the circulator according to the target pulse light; a demodulation unit, configured to demodulate an interference result of the first reflected light signal and the second reflected light signal to obtain phase information corresponding to the interference result; A determination unit is used to determine the noise signal in the downhole formation environment according to the phase information.

11. A non-volatile storage medium, characterized in that: The non-volatile storage medium includes a stored program, wherein when the program is executed, the device where the non-volatile storage medium is located is controlled to execute the method according to any one of claims 1 to 8.

12. A computer device, characterized in that: include: Memory and processor, The memory stores a computer program; The processor is used to execute the computer program stored in the memory, and when the computer program is run, the processor is enabled to execute the method according to any one of claims 1 to 8.

Images