On-site monitoring system for fracturing cracks in oil-gas well based on acoustic emission

Abstract

The utility model relates to an oil and gas well downhole fracturing crack field monitoring system based on acoustic emission, and relates to the field of oil and gas exploitation, and the oil and gas well downhole fracturing crack field monitoring system based on acoustic emission comprises a signal acquisition module and a data processing module; the signal acquisition module comprises a buried sensing rod, an acoustic emission sensor, a signal amplifier and an intelligent acquisition device. The data processing module is located on the ground, the data processing module is in communication connection with the output end of the intelligent acquisition device, and the data processing module is used for calculating, processing and displaying the digital signals output by the intelligent acquisition device. According to the system, the buried sensing rod is combined with the acoustic emission sensor, so that the system can efficiently sense and conduct weak acoustic emission signals generated by crack propagation in the reservoir. The method improves sensitivity and accuracy of signal acquisition, and has important guiding significance for increasing production and efficiency of oil and gas fields.

Description

Technical Field

[0001] This application relates to the field of oil and gas exploitation, and particularly to a field monitoring system for downhole fracturing cracks in oil and gas based on acoustic emission. Background Art

[0002] In the development of low-permeability unconventional oil and gas reservoirs such as shale and tight reservoirs, in order to improve the permeability and conductivity of the reservoir and increase the production and efficiency of oil and gas fields, it is crucial to perform volume fracturing operations of injecting water and gas into the reservoir. The process of volume fracturing aims to generate a complex fracture system as an effective channel for oil and gas production.

[0003] During the volume fracturing process, the reservoir rock will undergo local fractures under the action of external loads, and then release elastic waves, namely acoustic emission signals. The characteristics of acoustic emission signals such as waveform, frequency, energy, and amplitude contain rich information about the nature of reservoir fracture evolution. Therefore, in-depth study of the acoustic emission response characteristics at the oil and gas field exploitation site is of great significance for accurately describing the propagation type, orientation, size of fractures, and the formation mechanism of the entire fracture network.

[0004] However, in the actual operation at the oil and gas field exploitation site, there is a major technical problem: the energy of the acoustic emission signals generated by fracture propagation in the reservoir is extremely low, and due to the heterogeneity and anisotropy of the reservoir rock, these signals are extremely prone to attenuation during propagation, resulting in difficulty for near-surface monitoring equipment to efficiently sense and collect these weak signals.

[0005] Therefore, for the development of low-permeability oil and gas reservoirs such as shale and tight reservoirs, studying an efficient acoustic emission signal sensing, acquisition, and transmission system and combining it with real-time data analysis technology is the key to solving the problem of fracture monitoring at the oil and gas field exploitation site. Summary of the Invention

[0006] In order to improve the defect that it is difficult for monitoring equipment to efficiently collect acoustic emission signals in related technologies, this application provides a field monitoring system for downhole fracturing cracks in oil and gas based on acoustic emission.

[0007] The field monitoring system for downhole fracturing cracks in oil and gas based on acoustic emission provided by this application adopts the following technical solutions:

[0008] A field monitoring system for downhole fracturing cracks in oil and gas based on acoustic emission, the monitoring system includes a signal acquisition module and a data processing module;

[0009] The signal acquisition module includes:

[0010] A buried sensing rod, the buried sensing rod is buried underground around the oil and gas well, and the buried sensing rod is used to sense and conduct acoustic emission signals;

[0011] An acoustic emission sensor, which is attached to the top of a buried sensing rod through a coupling agent, and is used to receive the acoustic emission signal conducted by the buried sensing rod and convert it into an electrical signal;

[0012] A signal amplifier, which is located on the ground, and the input end of the signal amplifier is communicatively connected to the output end of the acoustic emission sensor through a BNC cable;

[0013] An intelligent acquisition device, which is located on the ground, and the input end of the intelligent acquisition device is communicatively connected to the output end of the signal amplifier through a BNC cable, and the intelligent acquisition device is used to convert the acoustic emission analog signal output by the signal amplifier into a digital signal;

[0014] The data processing module is located on the ground, and is communicatively connected to the output end of the intelligent acquisition device, and is used to calculate, process and display the digital signal output by the intelligent acquisition device.

[0015] Optionally, the data processing module includes a data receiving device, a calculation server and a display device;

[0016] The input end of the data receiving device is communicatively connected to the output end of the intelligent acquisition device, and the data receiving device is used to receive the digital signal output by the intelligent acquisition device and transmit it to the on-site calculation server through a network cable;

[0017] The on-site calculation server is communicatively connected to the data receiving device through a network cable, the output end of the calculation server is communicatively connected to the display device, and the calculation server is used to receive the digital signal output by the data receiving device and perform calculations, and then display the calculated result in real time through the display device.

[0018] Optionally, there are multiple groups of signal acquisition modules, and the multiple groups of signal acquisition modules are arranged in a circular array with the location of the oil and gas well as the center.

[0019] Optionally, the distance between the burial position of the buried sensing rod and the location of the oil and gas well is 100 - 500 m.

[0020] Optionally, the buried sensing rod is buried perpendicular to the horizontal plane, and the depth between the top of the buried sensing rod and the ground surface is 1 m.

[0021] Optionally, the buried sensing rod is a steel drill rod.

[0022] Optionally, the signal amplifier amplifies the weak electrical signal of the acoustic emission signal sensed by the acoustic emission sensor by 100 times and inputs it into the intelligent acquisition device.

[0023] Optionally, the intelligent collection device and the data receiving device communicate and transmit data via LoRa.

[0024] In summary, the present application includes at least one of the following beneficial technical effects:

[0025] 1. This application reduces the attenuation of signals during propagation by burying the buried sensing rod directly underground, closer to the sound source; the acoustic emission sensor is tightly fitted to the top of the sensing rod through a coupling agent to effectively receive the transmitted acoustic emission signal; the signal amplifier amplifies the weak electrical signal to ensure that the signal strength is sufficient to be accurately collected and processed by subsequent equipment. Through the combination of the buried sensing rod and the acoustic emission sensor, the system can efficiently sense and transmit the weak acoustic emission signals generated by the expansion of cracks in the reservoir. The signal amplifier further amplifies these weak signals to ensure that the signal is not attenuated too much during transmission, thereby improving the sensitivity and accuracy of signal acquisition.

[0026] 2. The monitoring system of this application adopts multiple groups of signal acquisition modules to be arranged in a circle with the oil and gas well as the center, which can monitor the crack expansion situation in all directions and angles, and improve the comprehensiveness and accuracy of monitoring. And the distance between the buried position of the buried sensing rod and the location of the oil and gas well is controlled at 100-500m, which effectively avoids the problem of signal interference between the various signal acquisition modules.

[0027] 3. The system is equipped with a data processing module, including a data receiving device, a computing server and a display device, which can receive, process and display monitoring data in real time, providing instant feedback to on-site operators. LoRa and other efficient communication technologies are used between the intelligent acquisition device and the data receiving device to ensure the stability and reliability of data transmission. The processing results are displayed in real time through the display device, so that operators can intuitively understand the crack expansion and make decisions in time. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of an acoustic emission-based field monitoring system for oil and gas well fracturing cracks in an embodiment of the present application;

[0029] Figure 2 It is a distribution state diagram of the signal acquisition module 1 of the monitoring system of the embodiment of the present application in actual application.

[0030] Explanation of the accompanying drawings: 1. Signal acquisition module; 11. Buried sensing rod; 12. Acoustic emission sensor; 13. Signal amplifier; 14. Intelligent acquisition device; 2. Data processing module; 21. Data receiving device; 22. Computing server; 23. Display device. DETAILED DESCRIPTION

[0031] The following is combined with Figure 1-2A further detailed description of the present application is provided.

[0032] An embodiment of the present application discloses an on-site monitoring system for hydraulic fracturing cracks in oil and gas wells based on acoustic emission. Refer to Figure 1 , an on-site monitoring system for hydraulic fracturing cracks in oil and gas wells based on acoustic emission includes a signal acquisition module 1 and a data processing module 2.

[0033] Refer to Figure 1 , the signal acquisition module 1 includes a buried sensing rod 11, an acoustic emission sensor 12, a signal amplifier 13, and an intelligent acquisition device 14.

[0034] Refer to Figure 1 , the buried sensing rod 11 is buried perpendicular to the horizontal plane. When burying, it is calibrated to be perpendicular to the horizontal plane by a level. The distance between it and the location of the oil and gas well is 100 - 500 m, and the depth between its top and the ground surface is 1 m. The buried sensing rod 11 is used to sense and conduct the acoustic emission signals generated by the crack propagation in the reservoir. The buried sensing rod 11 is made of steel drill rod. As a metal material, the steel drill rod has good conductivity. When elastic waves propagate near the steel drill rod, the steel drill rod will act as a sensor to receive and conduct these waves. Due to the material characteristics of the steel drill rod, the steel drill rod can more effectively receive and propagate these weak acoustic emission signals. When elastic waves hit the steel drill rod, it will cause slight vibrations of the steel drill rod. These vibrations can be captured by the acoustic emission sensor 12 installed on the steel drill rod and converted into electrical signals for further processing.

[0035] Refer to Figure 1 , the acoustic emission sensor 12 is attached to the top of the buried sensing rod 11 through a couplant. The acoustic emission sensor 12 is used to receive the acoustic emission signals conducted by the buried sensing rod 11 and can convert the acoustic emission signals generated by volume fracturing into weak electrical signals.

[0036] Refer to Figure 1 , the signal amplifier 13 is located on the ground, and its input end is communicatively connected to the output end of the acoustic emission sensor 12 through a BNC cable. The signal amplifier 13 amplifies the weak electrical signals sensed by the acoustic emission sensor 12 by 100 times to ensure that the signal intensity is sufficient to be accurately collected by subsequent devices.

[0037] Refer to Figure 1 , the intelligent acquisition device 14 is also located on the ground, and its input end is communicatively connected to the output end of the signal amplifier 13 through a BNC cable. The intelligent acquisition device 14 converts the acoustic emission analog signals output by the signal amplifier 13 into digital signals, providing a basis for subsequent data processing.

[0038] Refer to Figure 1 , the data processing module 2 includes a data receiving device 21, a computing server 22, and a display device 23.

[0039] Reference Figure 1 The input end of the data receiving device 21 and the output end of the intelligent collection device 14 realize wireless communication and data transmission through LoRa. The data receiving device 21 is used to receive the digital signal output by the intelligent collection device 14 and transmit the data to the on-site computing server 22 through the network cable.

[0040] Reference Figure 1 The computing server 22 is connected to the data receiving device 21 through a network cable, receives the digital signal output by the data receiving device 21, and performs real-time computing. The output end of the computing server 22 is connected to the display device 23, and the processed result is displayed in real time through the display device 23 to provide instant feedback to the on-site operator.

[0041] Reference Figure 1 The display device 23 is used to display the monitoring data processed by the computing server 22 and intuitively show the crack expansion situation.

[0042] Reference Figure 2 In practical applications, the system may be provided with multiple groups of signal acquisition modules 1, which are arranged in a circle with the oil and gas well as the center, to ensure all-round and multi-angle monitoring of crack expansion. Multiple groups of signal acquisition modules 1 work together to improve the comprehensiveness and accuracy of monitoring. The distance between the buried position of the buried sensing rod 11 and the oil and gas well is controlled at 100-500m, which effectively avoids the problem of signal interference between the various signal acquisition modules 1.

[0043] The implementation principle of the on-site monitoring system for hydraulic fracturing cracks in oil and gas wells based on acoustic emission in the embodiment of the present application is as follows: during the acquisition and monitoring process, in the on-site monitoring system for hydraulic fracturing cracks in oil and gas wells based on acoustic emission,

[0044] System initialization and preparation, first, in the ground around the oil and gas wells, buried sensing rods 11 made of steel drill are vertically buried according to the preset spacing and depth. These sensing rods will serve as the receiving medium for the acoustic emission signal. Then, the acoustic emission sensor 12 is tightly attached to the top of the buried sensing rod 11 through the coupling agent to ensure that the sensor can effectively receive the acoustic emission signal conducted by the sensing rod. Then, the signal amplifier 13, the intelligent acquisition device 14, the data receiving device 21, the computing server 22 and the display device 23 are connected through appropriate cables or wireless communication technology, and the system is debugged to ensure normal communication and data transmission between the components.

[0045] Signal acquisition process: When a fracturing operation is carried out on an oil and gas well, the rocks in the reservoir will generate fractures under the action of pressure, and acoustic emission phenomena will occur. These acoustic emission signals are first sensed by the buried sensing rod 11 and conducted to its top. The acoustic emission sensor 12 converts the received acoustic emission signals into electrical signals and transmits them to the signal amplifier 13 through BNC cables. The signal amplifier 13 amplifies the weak electrical signals to improve the signal strength and signal-to-noise ratio. The amplified electrical signals are transmitted to the intelligent acquisition device 14, and the intelligent acquisition device 14 converts them into digital signals. This step ensures that the signals can be processed and stored in digital form for subsequent operations.

[0046] Data processing and display: The intelligent acquisition device 14 transmits the converted digital signals to the data receiving device 21 in a wired or wireless manner. The data receiving device 21 then transmits the signals to the on-site computing server 22 through a network cable. After receiving the digital signals, the computing server 22 performs real-time computational processing on the signals using preset algorithms and models. These processes include but are not limited to signal denoising, feature extraction, fracture location, etc. The computing server 22 displays the processed results on the display device 23 in real time. Operators can intuitively understand information such as the propagation situation, shape, and location of the fractures by observing the data charts and images on the display device 23, and make corresponding decisions and adjustments based on this.

[0047] The above are all preferred embodiments of this application. The protection scope of this application is not limited by this. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. An oil and gas well downhole fracturing crack field monitoring system based on acoustic emission, characterized in that: The monitoring system comprises a signal acquisition module (1) and a data processing module (2); The signal acquisition module (1) comprises: A buried sensing rod (11), wherein the buried sensing rod (11) is buried underground around an oil and gas well, and the buried sensing rod (11) is used to sense and conduct acoustic emission signals; An acoustic emission sensor (12), wherein the acoustic emission sensor (12) is attached to the top of the buried sensing rod (11) via a coupling agent, and the acoustic emission sensor (12) is used to receive the acoustic emission signal conducted by the buried sensing rod (11) and convert it into an electrical signal; A signal amplifier (13), the signal amplifier (13) is located on the ground, and the input end of the signal amplifier (13) is communicatively connected to the output end of the acoustic emission sensor (12) via a BNC cable; An intelligent collection device (14), the intelligent collection device (14) is located on the ground, the input end of the intelligent collection device (14) is communicatively connected to the output end of the signal amplifier (13) via a BNC cable, and the intelligent collection device (14) is used to convert the acoustic emission analog signal output by the signal amplifier (13) into a digital signal; The data processing module (2) is located on the ground, the data processing module (2) is communicatively connected to the output end of the intelligent acquisition device (14), and the data processing module (2) is used to perform calculation processing and display on the digital signal output by the intelligent acquisition device (14).

2. The oil and gas well downhole fracturing crack field monitoring system based on acoustic emission according to claim 1 is characterized in that: The data processing module (2) comprises a data receiving device (21), a computing server (22) and a display device (23); The input end of the data receiving device (21) is communicatively connected to the output end of the intelligent collection device (14), and the data receiving device (21) is used to receive the digital signal output by the intelligent collection device (14) and transmit it to the on-site computing server (22) via a network cable; The on-site calculation server (22) is connected to the data receiving device (21) via a network cable, and the output end of the calculation server (22) is connected to the display device (23). The calculation server (22) is used to receive the digital signal output by the data receiving device (21) and perform calculations, and then display the calculated results in real time via the display device (23).

3. The oil and gas well downhole fracturing crack field monitoring system based on acoustic emission according to claim 2 is characterized by: The signal acquisition modules (1) are provided in a plurality of groups, and the plurality of groups of signal acquisition modules (1) are arranged and distributed in a circle with the location of the oil and gas well as the center.

4. The oil and gas well downhole fracturing crack field monitoring system based on acoustic emission according to any one of claims 1 to 3, characterized in that: The distance between the buried position of the buried sensing rod (11) and the location of the oil and gas well is 100-500m.

5. The oil and gas well downhole fracturing crack field monitoring system based on acoustic emission according to any one of claims 1 to 3, characterized in that: The buried sensing rod (11) is buried perpendicular to the horizontal plane, and the depth between the top of the buried sensing rod (11) and the ground surface is 1 m.

6. The oil and gas well downhole fracturing crack field monitoring system based on acoustic emission according to any one of claims 1 to 3, characterized in that: The buried sensing rod (11) is a steel chisel.

7. An acoustic emission-based oil and gas well downhole fracturing crack field monitoring system according to any one of claims 1 to 3, characterized in that: The signal amplifier (13) amplifies the weak electrical signal of the acoustic emission signal sensed by the acoustic emission sensor (12) by 100 times, and inputs the amplified signal into the intelligent collection device (14).

8. The oil and gas well downhole fracturing crack field monitoring system based on acoustic emission according to claim 3 is characterized by: The intelligent collection device (14) and the data receiving device (21) communicate and transmit data via LoRa.

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