Method for monitoring regional fracturing influence range based on distributed optical fiber acoustic wave sensing

Abstract

The invention relates to a regional fracturing influence range monitoring method based on distributed optical fiber sound wave sensing, and the method comprises the steps: pre-arranging a DAS monitoring system in a fracturing region, and collecting an original signal of the fracturing region through the DAS monitoring system; identifying the original signal, and obtaining a micro-seismic signal and first arrival time of a longitudinal wave in the micro-seismic signal; based on the first arrival time of longitudinal waves in the micro-seismic signals, the distribution position of micro-seismic events in the fracturing area is determined; according to the distribution position of the micro-seismic event in the fracturing area, the hydraulic fracturing influence range in the fracturing area is determined, the original signal of the fracturing area is collected through the DAS monitoring system, the distribution position of the micro-seismic event in the fracturing area is determined by processing the original signal, accurate characterization of the hydraulic fracturing crack propagation form is achieved, and the hydraulic fracturing influence range in the fracturing area is determined. The accuracy and efficiency of determining the effective influence range of hydraulic fracturing are improved, reference can be provided for optimization of a hydraulic fracturing scheme, the hydraulic fracturing pressure relief effect is improved, and the production safety of a coal mine is guaranteed.

Description

Technical Field

[0001] The present disclosure relates to the field of coal mine safety technology, and in particular to a method for monitoring the impact range of regional fracturing based on distributed optical fiber acoustic wave sensing. Background Art

[0002] Deep coal mining often faces the problem of frequent rock bursts, which pose a serious threat to personnel safety and adversely impact the efficient extraction of coal resources. Dynamic loads from the breaking of thick, hard roofs are a major factor in inducing rock bursts. Regional hydraulic fracturing and pressure relief projects have been implemented to reduce these dynamic loads, and while these efforts have achieved some success, there is no effective way to accurately characterize the propagation morphology of hydraulic fracturing cracks, making it impossible to accurately determine the effective impact range of hydraulic fracturing. Therefore, accurately and efficiently determining the impact range of hydraulic fracturing has become a pressing issue. Summary of the Invention

[0003] The present disclosure aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] The technical solutions disclosed in this disclosure are as follows:

[0005] According to a first aspect of an embodiment of the present disclosure, a method for monitoring the impact range of regional fracturing based on distributed fiber optic acoustic sensing is provided, the method comprising: pre-deploying a distributed fiber optic acoustic sensing (DAS) monitoring system in a fracturing area, and having the DAS monitoring system collect original signals from the fracturing area; identifying the original signals to obtain microseismic signals and the first arrival time of longitudinal waves in the microseismic signals; determining the distribution position of microseismic events in the fracturing area based on the first arrival time of longitudinal waves in the microseismic signals; and determining the impact range of hydraulic fracturing in the fracturing area based on the distribution position of microseismic events in the fracturing area.

[0006] According to a second aspect of an embodiment of the present disclosure, a monitoring device for a regional hydraulic fracturing influence range based on distributed optical fiber acoustic sensing is provided, comprising: an acquisition module for pre-deploying a distributed optical fiber acoustic sensing (DAS) monitoring system in a hydraulic fracturing region, wherein the DAS monitoring system acquires original signals from the hydraulic fracturing region; an identification module for identifying the original signals, obtaining microseismic signals and the first arrival time of longitudinal waves in the microseismic signals; a first determination module for determining the distribution position of microseismic events in the hydraulic fracturing region based on the first arrival time of longitudinal waves in the microseismic signals; and a second determination module for determining the hydraulic fracturing influence range in the hydraulic fracturing region based on the distribution position of microseismic events in the hydraulic fracturing region.

[0007] According to a third aspect of an embodiment of the present disclosure, an electronic device is provided, comprising: a processor; and a memory for storing executable instructions of the processor; wherein the processor is configured to execute the instructions to implement the method for monitoring the regional fracturing impact range based on distributed fiber optic acoustic wave sensing as described in the first aspect of the embodiment of the present disclosure.

[0008] According to a fourth aspect of an embodiment of the present disclosure, a computer-readable storage medium is provided. When instructions in the computer-readable storage medium are executed by a processor of an electronic device, the electronic device is enabled to perform the method for monitoring the regional fracturing impact range based on distributed fiber optic acoustic wave sensing as described in the first aspect of the embodiment of the present disclosure.

[0009] The technical solutions provided by the embodiments of the present disclosure bring at least the following beneficial effects:

[0010] In an embodiment of the present disclosure, a DAS monitoring system is pre-deployed in a fracturing area, and the DAS monitoring system collects original signals from the fracturing area, identifies the original signals, obtains microseismic signals and the first arrival time of longitudinal waves in the microseismic signals, determines the distribution position of microseismic events in the fracturing area based on the first arrival time of longitudinal waves in the microseismic signals, and determines the influence range of hydraulic fracturing in the fracturing area according to the distribution position of microseismic events in the fracturing area. Therefore, the present disclosure collects original signals from the fracturing area through the DAS monitoring system, determines the distribution position of microseismic events in the fracturing area by processing the original signals, realizes accurate characterization of the expansion morphology of hydraulic fracturing cracks, improves the accuracy and efficiency of determining the effective influence range of hydraulic fracturing, can provide a reference for optimizing hydraulic fracturing schemes, improves the hydraulic fracturing pressure relief effect, and ensures the production safety of coal mines.

[0011] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings herein are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the description are used to explain the principles of the present disclosure, and do not constitute an improper limitation of the present disclosure.

[0013] Figure 1 The present invention is a flow chart showing a method for monitoring the impact range of regional fracturing based on distributed fiber optic acoustic sensing according to an exemplary embodiment.

[0014] FIG2( a ) is a schematic plan view of an optical fiber arrangement according to an exemplary embodiment;

[0015] FIG2( b ) is a schematic cross-sectional view of an optical fiber cloth according to an exemplary embodiment;

[0016] Figure 3 is a schematic diagram showing a backplane optical fiber arrangement according to an exemplary embodiment;

[0017] Figure 4 The figure is a flow chart showing a method for monitoring the impact range of regional fracturing based on distributed fiber optic acoustic sensing according to another exemplary embodiment.

[0018] Figure 5 is a YZ plane projection diagram of microseismic event distribution according to an exemplary embodiment;

[0019] Figure 6 is a YZ plane projection diagram of the optimized distribution of microseismic events according to an exemplary embodiment;

[0020] Figure 7 The block diagram shows a device for monitoring the impact range of regional fracturing based on distributed fiber optic acoustic sensing according to an exemplary embodiment.

[0021] Figure 8 It is a block diagram of an electronic device according to an exemplary embodiment. DETAILED DESCRIPTION

[0022] In order to enable ordinary persons in the art to better understand the technical solutions of the present disclosure, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings.

[0023] It should be noted that the terms "first," "second," and the like in the specification and claims of the present disclosure and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the numbers used in this manner are interchangeable where appropriate so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure as detailed in the appended claims.

[0024] The following embodiments describe in detail the method, device, and electronic device for monitoring the impact range of regional fracturing based on distributed fiber optic acoustic wave sensing proposed in the present disclosure.

[0025] Figure 1 A schematic flow chart of a method for monitoring the impact range of regional fracturing based on distributed fiber optic acoustic sensing provided in an embodiment of the present disclosure.

[0026] like Figure 1 As shown, the method for monitoring the regional fracturing impact range based on distributed optical fiber acoustic wave sensing proposed in this embodiment includes the following steps:

[0027] S101, pre-deploy a distributed optical fiber acoustic sensor (DAS) monitoring system in the fracturing area, and the DAS monitoring system collects original signals from the fracturing area.

[0028] In an embodiment of the present disclosure, construction parameters of the optical fiber hole are obtained, and the optical fiber hole construction is performed according to the construction parameters, wherein the construction parameters include at least quantity, spacing, angle, depth and diameter. The layout method of the optical fiber is obtained, and the optical fiber is laid in the optical fiber hole according to the layout method. The layout position of the demodulator is obtained, and the demodulator is laid according to the layout position to complete the layout of the distributed optical fiber acoustic sensing (DAS) monitoring system.

[0029] For example, as shown in Figure 2(a), the fracturing drilling site is the core area for fracturing operations. There are 6 fracturing (drilling) holes (1# drilling hole-6# drilling hole) distributed in the fracturing drilling site. Each fracturing borehole extends from the fracturing drilling site to the right, passing through different areas, namely fracturing areas. The fiber hole spacing can be set to 150m and 200m, and the fiber diameter can be set to 5mm. As shown in Figure 2(b), according to the fiber hole mark in Figure 2(b), a directional drill is used to drill into the coal seam roof at a depth of 95m at a direction of 52° (angle) to the normal plane of the lane to obtain a fiber hole. Four fiber holes (1-1#-1-4#) are arranged in the return air lane, and fiber optic laying is carried out in the return air lane: the optical fiber is arranged along the return air lane from the collection point and is hung on the wire rack (only for transmission). ) until the return air lane cut-eye position, after passing the cut-eye position, the optical fiber is laid along the edge of the hardened road surface of the return air lane (for signal collection). If there is interference from stacked equipment or deep water area on the way, the optical fiber will be hung on the wire rack and laid to the 1-1# optical fiber hole, and 200m optical fiber will be reserved and wound for standby, and so on, until it is laid to the 1-4# optical fiber hole of the return air lane. Four optical fiber holes (2-1#-2-4#) are arranged in the main transport lane, and optical fiber is laid in the main transport lane: starting from the tail end of the optical fiber in the return air lane, the optical fiber is laid along the road surface in the opposite direction until it reaches the junction of the south wing drainage lane and the main transport lane. The optical fiber is laid as parallel to the outgoing optical fiber as possible, and then the optical fiber is passed through the drainage lane into the main transport lane. The laying method in the main transport lane is similar to that of the return air lane, but a free end is formed at the tail end, and no loop is formed.

[0030] It should be noted that after the drilling operation is completed, the optical fiber is wrapped and fixed with an unplasticized polyvinyl chloride (UPVC) casing and sent to the bottom of the fiber hole. The length of the UPVC casing can be 4m, with an outer diameter of 50mm and an inner diameter of 35mm. The bottom casing is reserved with a grouting hole. Before being sent into the fiber hole, the optical fiber is wrapped at the end and fixed with a cable tie. In order to prevent the end optical fiber from being pulled off by friction, a tough braided tape is used to protect the end. The UPVC casing is sent into the fiber hole in sections, and each section is connected by a snap-through and high-strength glue until it is sent to the bottom of the fiber hole. After the optical fiber is placed in the fiber hole, grouting is used to seal the fiber hole and the outer edge of the PVC pipe to ensure a good grouting filling effect and avoid gaps between the optical fiber and the hole wall. The fiber optic layout plan for the tunnel floor is mainly arranged along the edge of the hardened road surface, for example: Figure 3 As shown, the optical fiber is first placed along the edge of the hardened road surface, and then filled with cement mortar to ensure good contact of the optical fiber along the hardened road surface.

[0031] It should be noted that, considering the needs of dust prevention, cooling and electricity consumption of the acoustic / vibration signal demodulator, the demodulator can be set in the tunnel opposite the fracturing drilling site, and the demodulator and working computer can be placed in a coal safety explosion-proof box.

[0032] In an embodiment of the present disclosure, after determining that the DAS monitoring system is deployed, the connectivity of the optical fiber is tested using an optical time domain reflectometer. In response to the connectivity of the optical fiber passing the test, the target position of the optical fiber is marked, and the target position is set as the node position in the DAS monitoring system.

[0033] Optionally, after the DAS monitoring system is deployed, all breakpoints are reconnected using a dedicated fusion splicer, and the connectivity of the optical fiber is tested using an optical time domain reflectometer (ODTR) to ensure that all optical fibers are in a path state. Before the DAS monitoring system formally collects the original signal from the fracturing area, the target positions of the optical fibers along the line (such as the turning positions and connection points of the optical fibers) are marked and located using a hammering method, and the target positions are set as node positions in the DAS monitoring system to complete positioning matching in the DAS monitoring system.

[0034] In the embodiment of the present disclosure, after the monitoring requirements of the hydraulic fracturing impact range are obtained, a call instruction of the DAS monitoring system can be generated, and the DAS monitoring system is called through the call instruction to collect the original signal of the fracturing area.

[0035] S102: Identify the original signal to obtain the microseismic signal and the first arrival time of the longitudinal wave in the microseismic signal.

[0036] It should be noted that in order to describe the spatiotemporal distribution of microseismic events caused by hydraulic fracturing, it is necessary to identify the microseismic signals from the original signals and obtain the first arrival time of the P-wave in the microseismic signals.

[0037] Optionally, the target signal can be identified based on a long-short time window algorithm to obtain a microseismic signal, and the time when the microseismic signal is first identified is used as the first arrival time of the longitudinal wave in the microseismic signal.

[0038] S103: Determine the distribution position of the microseismic events in the fracturing area based on the first arrival time of the longitudinal wave in the microseismic signal.

[0039] In the embodiment of the present disclosure, after obtaining the first arrival time of the longitudinal wave in the microseismic signal, the microseismic event in the fracturing area can be located based on the first arrival time of the longitudinal wave to determine the distribution position of the microseismic event in the fracturing area.

[0040] Optionally, the distribution location of the microseismic event can be determined based on the first arrival time of the longitudinal wave in the microseismic signal in combination with a Monte Carlo algorithm (Markov Chain Monte Carlo, MCMC for short) based on Bayesian theory.

[0041] S104: Determine the hydraulic fracturing influence range in the fracturing area according to the distribution positions of the microseismic events in the fracturing area.

[0042] The hydraulic fracturing impact range refers to the volume range spatially enclosed by the hydraulic fractures generated by all fracturing segments of each fracturing borehole.

[0043] In the embodiment of the present disclosure, after the distribution positions of the microseismic events in the fracturing region are acquired, the hydraulic fracturing influence range in the fracturing region can be determined according to the distribution positions of the microseismic events in the fracturing region.

[0044] In summary, the embodiment of the present disclosure provides a monitoring method for the regional fracturing influence range based on distributed fiber optic acoustic wave sensing. By pre-deploying a distributed fiber optic acoustic wave sensing DAS monitoring system in the fracturing area, the DAS monitoring system collects the original signal of the fracturing area, identifies the original signal, obtains the microseismic signal and the first arrival time of the longitudinal wave in the microseismic signal, determines the distribution position of the microseismic event in the fracturing area based on the first arrival time of the longitudinal wave in the microseismic signal, and determines the hydraulic fracturing influence range in the fracturing area according to the distribution position of the microseismic event in the fracturing area. Therefore, the present disclosure collects the original signal of the fracturing area through the DAS monitoring system, determines the distribution position of the microseismic event in the fracturing area by processing the original signal, realizes the accurate characterization of the hydraulic fracturing crack expansion morphology, improves the accuracy and efficiency of determining the effective influence range of hydraulic fracturing, can provide a reference for the optimization of hydraulic fracturing scheme, improves the hydraulic fracturing pressure relief effect, and ensures the production safety of coal mines.

[0045] Figure 4 A schematic flow chart of a method for monitoring the impact range of regional fracturing based on distributed fiber optic acoustic sensing provided in an embodiment of the present disclosure.

[0046] like Figure 4 As shown, the method for monitoring the regional fracturing impact range based on distributed optical fiber acoustic wave sensing proposed in this embodiment includes the following steps:

[0047] S401, pre-deploy a distributed optical fiber acoustic sensor (DAS) monitoring system in the fracturing area, and the DAS monitoring system collects original signals from the fracturing area.

[0048] S402: Preprocess the original signal to obtain a target signal.

[0049] It should be noted that in the underground environment of coal mines, there are many interference signals, such as interference signals generated by water pumps, drilling sites, etc., which increase the difficulty of identifying microseismic signals. Therefore, the original signal can be preprocessed to obtain the target signal to ensure the quality of the target signal.

[0050] Optionally, the original signal is first subjected to a low-frequency filtering process of 1-100 Hz to eliminate high-frequency noise signals and improve the signal-to-noise ratio of the microseismic signal. Secondly, considering the interference signals generated by water pumps, drilling sites, etc., the optical fiber channels with continuous interference signals nearby are not processed to reduce the error caused by misidentifying interference signals generated by water pumps, drilling sites, etc. as microseismic signals.

[0051] S403 : Identify the target signal based on the long-short time window algorithm to obtain the microseismic signal, and use the time when the microseismic signal is first identified as the first arrival time of the longitudinal wave in the microseismic signal.

[0052] The long time average (LTA) is used to reflect the energy level of the target signal over a long period of time, and the short time average (STA) is used to reflect the energy level of the target signal over a short period of time.

[0053] Optionally, the long-short time window algorithm identifies microseismic signals by calculating the energy density ratio of the short-time window and long-time window signals, and uses the energy density ratio of the short-time window and long-time window signals as the characteristic function, that is, the ratio of STA to LTA is the characteristic function. The length of the short-time window nsta can be set to 0.02 seconds, and the length of the long-time window nlta can be set to 0.04 seconds. When the value of the characteristic function STA / LTA is greater than 4.0, the microseismic signal in the target signal is identified, and the time when the microseismic signal is first identified is used as the first arrival time of the longitudinal wave (P wave) in the microseismic signal.

[0054] Optionally, in order to improve the accuracy of the first arrival time of the P-wave in the microseismic signal, the channel with the highest signal-to-noise ratio can be selected as the reference channel, and the microseismic signal of the reference channel is cross-correlated with the signals of the remaining channels, and the signals with a cross-correlation coefficient < 0.7 are eliminated. For signals with a strong cross-correlation coefficient, the first arrival time of the P-wave determined by STA / LTA is corrected at the moment of maximum cross-correlation, so as to ensure the accuracy of the first arrival time of the P-wave. At the same time, due to the small monitoring range, the first arrival P-wave has not undergone complex scattering. Therefore, the same microseismic signal collected by different channels of the DAS monitoring system should have a similar waveform, and the screening of the correlation also ensures the accuracy of the P-wave. The first arrival time of the wave comes from the same microseismic event, avoiding the problem of identifying non-microseismic signals as microseismic signals. In actual monitoring, the vibration signal caused by fracturing is relatively weak, and only the channels close to the fracturing or rock fracture can collect the signal. In order to ensure the accuracy and precision of the distribution position of subsequent microseismic events, the first arrival time of the longitudinal wave in the microseismic signal can be screened: (1) For the same microseismic event, the number of effective DAS monitoring system acquisition channels is greater than 5; (2) Considering that continuous monitoring system channel acquisition is difficult to provide effective azimuth information, the maximum spacing between effective channels is required to be greater than 200m; (3) The signal-to-noise ratio of the microseismic signal is not less than 2.0.

[0055] S404: Determine the distribution location of microseismic events in the fracturing area based on the first arrival time of the longitudinal wave in the microseismic signal and the Markov chain Monte Carlo algorithm.

[0056] In the embodiment of the present disclosure, after obtaining the first arrival time of the longitudinal wave in the microseismic signal, the distribution position of the microseismic event in the fracturing area can be determined based on the first arrival time of the longitudinal wave in the microseismic signal combined with the Markov Chain Monte Carlo (MAMC) algorithm.

[0057] Optionally, MCMC is used to approximate the posterior probability density distribution of the earthquake location, invert the parameters m = (x, y, z, t, v), i.e., the earthquake location (x, y, z), the time of occurrence t, and the earthquake velocity v, randomly generate initial parameters from the prior distribution, perturb the current parameters according to the proposed distribution to obtain new parameters, calculate the acceptance ratio, decide whether to accept the new parameters, update the parameters based on the comparison result of the random number and the acceptance ratio, repeat the iteration until convergence, set the total number of iterations to 60,000, discard the first 10,000 to reduce the initial impact, and use the last 50,000 models to calculate the final earthquake location, thereby determining the distribution location of all microseismic events in the fracturing area.

[0058] S405 : Determine the distribution density of the microseismic events in the hydraulic fracturing area based on the distribution positions of the microseismic events in the hydraulic fracturing area.

[0059] S406: Determine the initial hydraulic fracturing influence range in the fracturing area based on the distribution density and a preset area division method.

[0060] Optionally, the preset area division method may be to divide the area into ellipses, cover the area with the highest distribution density with the ellipse, and determine the area covered by the ellipse as the initial hydraulic fracturing influence range in the fracturing area.

[0061] For example, in order to facilitate comparative analysis between fracturing holes, the coal seam dip-vertical (YZ) plane is projected and mapped. The fracturing holes at a height of 45m from the coal seam roof are collectively referred to as low-position holes (the vertical height of holes 1#, 3#, and 6# is 50m), and the fracturing holes at a height of 55m from the roof are collectively referred to as high-position holes (the vertical height of holes 2#, 4#, and 5# is 58m). Figure 5 As shown in the figure, the projections of the microseismic events caused by the six fracturing holes on the YZ plane are shown. The shaded area is the dense distribution area of ​​microseismic events, which is used to describe the hydraulic fracturing influence range of each fracturing hole. The distribution positions of the microseismic events generated by the six fracturing holes are basically elliptical. Among them, the fracturing influence range of the low-position holes is larger than that of the high-position holes, and the microseismic events show a downward shift trend. Since the vertical height of the 6# fracturing hole is 5m higher than that of the 1# and 3# fracturing holes, the downward shift trend of the microseismic signals generated during the fracturing process is not obvious. Microseismic events mostly occur in the middle sandstone layer (target area), while the microseismic events of the high-position fracturing holes are basically symmetrically distributed around the fracturing holes. The fracturing ranges of the six fracturing holes have a low overlap on the YZ plane, indicating that there is little mutual interference between the fracturing holes. At the same time, considering the staggered arrangement of the boreholes in the vertical direction, from the YZ plane, the six fracturing holes have achieved a complete through-cut of the roof. The projections of each elliptical surface on the coordinate axis are used as the quantitative value of the fracturing influence range.

[0062] S407, optimizing the initial hydraulic fracturing influence range in the fracturing area to determine the hydraulic fracturing influence range in the fracturing area.

[0063] In the embodiment of the present disclosure, the target area where the fracturing area is located is obtained, and the hydraulic fracturing influence range that does not belong to the target area is eliminated from the initial hydraulic fracturing influence range to determine the hydraulic fracturing influence range in the fracturing area.

[0064] For example, the target area of ​​the fracturing zone is the medium sandstone layer. Due to the downward movement trend of events in the low-position holes, these fractures cannot form effective through-cracks along the coal seam dip in the target layer. The downward-moving microseismic events are eliminated, and only the microseismic positions in the target layer are retained and the ellipse coverage area is corrected. The hydraulic fracturing influence range that does not belong to the medium sandstone layer is eliminated from the initial hydraulic fracturing influence range, such as Figure 6 As shown, the hydraulic fracturing impact range in the final fracturing area is determined.

[0065] In summary, the embodiment of the present disclosure provides a monitoring method for the regional hydraulic fracturing influence range based on distributed fiber optic acoustic wave sensing. A DAS monitoring system is pre-deployed in the hydraulic fracturing area. The DAS monitoring system collects the original signal of the hydraulic fracturing area, pre-processes the original signal to obtain the target signal, identifies the target signal based on the long-short time window algorithm to obtain the microseismic signal, and uses the time when the microseismic signal is first identified as the first arrival time of the longitudinal wave in the microseismic signal. Based on the first arrival time of the longitudinal wave in the microseismic signal combined with the Markov chain Monte Carlo algorithm, the distribution position of the microseismic events in the hydraulic fracturing area is determined. Based on the distribution position of the microseismic events in the hydraulic fracturing area, the distribution density of the microseismic events in the hydraulic fracturing area is determined. Based on the distribution density and the preset regional division method, the initial hydraulic fracturing influence range in the hydraulic fracturing area is determined. The initial hydraulic fracturing influence range in the hydraulic fracturing area is optimized to determine the hydraulic fracturing influence range in the hydraulic fracturing area. The influence range of hydraulic fracturing is determined by constructing fiber optic holes at a certain angle in two lanes of the working face and implanting distributed optical fibers in the fiber optic holes to construct a DAS monitoring system. By collecting the original signals in the fracturing area, the precise positioning of microseismic events during regional hydraulic fracturing can be achieved, providing data support for determining the influence range of hydraulic fracturing in the fracturing area. The long and short time window method is used to identify the microseismic signals and the first arrival time of the longitudinal wave in the microseismic signal from the original signal. Based on the first arrival time of the longitudinal wave in the microseismic signal combined with the Markov chain Monte Carlo algorithm, the distribution position of the microseismic events in the fracturing area is determined, which realizes the precise characterization of the expansion morphology of hydraulic fracturing cracks and improves the accuracy and efficiency of determining the influence range of hydraulic fracturing in the fracturing area. It is of great significance to the optimization design of regional fracturing schemes and the improvement of regional fracturing efficiency, which is beneficial to ensuring the normal production of coal mines and improving the economic benefits of coal mining enterprises.

[0066] Figure 7 FIG. 1 is a block diagram of a monitoring device for regional fracturing impact range based on distributed optical fiber acoustic wave sensing according to an exemplary embodiment. Figure 7As shown, the monitoring device 700 for regional fracturing influence range based on distributed optical fiber acoustic wave sensing according to the embodiment of the present disclosure may specifically include: a collection module 701 , an identification module 702 , a first determination module 703 and a second determination module 704 .

[0067] The acquisition module 701 is configured to pre-deploy a distributed optical fiber acoustic sensor (DAS) monitoring system in the fracturing area, and to collect the original signal of the fracturing area by the DAS monitoring system;

[0068] Identification module 702, used to identify the original signal, obtain the microseismic signal and the first arrival time of the longitudinal wave in the microseismic signal;

[0069] A first determination module 703 is configured to determine the distribution location of microseismic events in the fracturing region based on the first arrival time of the longitudinal wave in the microseismic signal;

[0070] The second determining module 704 is configured to determine the hydraulic fracturing influence range in the fracturing area based on the distribution of microseismic events in the fracturing area.

[0071] In one embodiment of the present disclosure, the process of pre-deploying a DAS monitoring system in a fracturing area includes: obtaining construction parameters of the optical fiber hole, and constructing the optical fiber hole according to the construction parameters, wherein the construction parameters include at least the number, spacing, angle, depth and diameter; obtaining a layout method of the optical fiber, and laying the optical fiber in the optical fiber hole according to the layout method; obtaining a layout position of a demodulator, and laying the demodulator according to the layout position.

[0072] In one embodiment of the present disclosure, after determining that the DAS monitoring system has been deployed, the process of pre-deploying the DAS monitoring system in the fracturing area includes: testing the connectivity of the optical fiber using an optical time domain reflectometer; in response to the connectivity of the optical fiber passing the test, marking a target position on the optical fiber, and setting the target position as a node position in the DAS monitoring system.

[0073] In one embodiment of the present disclosure, the identification module 702 is used to: preprocess the original signal to obtain a target signal; identify the target signal based on a long-short time window algorithm to obtain the microseismic signal, and use the time when the microseismic signal is first identified as the first arrival time of the longitudinal wave in the microseismic signal.

[0074] In one embodiment of the present disclosure, the first determination module 703 is configured to determine the distribution location of microseismic events in the fracturing region based on the first arrival time of the longitudinal wave in the microseismic signal in combination with a Markov chain Monte Carlo algorithm.

[0075] In one embodiment of the present disclosure, the second determination module 704 is used to: determine the distribution density of microseismic events in the fracturing area based on the distribution positions of the microseismic events in the fracturing area; determine the initial hydraulic fracturing influence range in the fracturing area based on the distribution density and a preset area division method; optimize the initial hydraulic fracturing influence range in the fracturing area to determine the hydraulic fracturing influence range in the fracturing area.

[0076] In one embodiment of the present disclosure, the second determination module 704 is configured to: obtain a target area where the hydraulic fracturing area is located; and remove the hydraulic fracturing influence range that does not belong to the target area from the initial hydraulic fracturing influence range to determine the hydraulic fracturing influence range in the hydraulic fracturing area.

[0077] In the embodiments of the present disclosure, the specific manner in which each module in the apparatus for monitoring the impact range of regional fracturing based on distributed fiber optic acoustic sensing in the above-mentioned embodiments performs operations has been described in detail in the embodiments of the method for monitoring the impact range of regional fracturing based on distributed fiber optic acoustic sensing, and will not be repeated here.

[0078] In summary, the embodiments of the present invention provide a monitoring device for the regional fracturing influence range based on distributed fiber optic acoustic wave sensing. A distributed fiber optic acoustic wave sensing DAS monitoring system is pre-deployed in the fracturing area. The DAS monitoring system collects the original signal of the fracturing area, identifies the original signal, obtains the microseismic signal and the first arrival time of the longitudinal wave in the microseismic signal, determines the distribution position of the microseismic event in the fracturing area based on the first arrival time of the longitudinal wave in the microseismic signal, and determines the hydraulic fracturing influence range in the fracturing area according to the distribution position of the microseismic event in the fracturing area. Therefore, the present invention collects the original signal of the fracturing area through the DAS monitoring system, determines the distribution position of the microseismic event in the fracturing area by processing the original signal, and realizes the accurate characterization of the expansion morphology of the hydraulic fracturing crack, which can provide a reference for the optimization of the hydraulic fracturing scheme, improve the hydraulic fracturing pressure relief effect, and ensure the production safety of the coal mine.

[0079] In order to implement the above embodiment, Figure 8 As shown, the present disclosure also proposes an electronic device 1000, which includes a memory 110, a processor 120, and a computer program stored in the memory and executable on the processor 120. When the processor 120 executes the program instructions, the method for monitoring the regional fracturing impact range based on distributed fiber optic acoustic wave sensing according to the above embodiment is implemented.

[0080] In order to implement the above embodiments, the present disclosure also proposes a computer-readable storage medium.

[0081] When the instructions in the computer-readable storage medium are executed by a processor of an electronic device, the electronic device is enabled to perform the aforementioned method for monitoring the impact range of regional fracturing based on distributed fiber-optic acoustic sensing. Alternatively, the computer-readable storage medium may be a ROM, random access memory (RAM), CD-ROM, magnetic tape, floppy disk, or optical data storage device.

[0082] Other embodiments of the present disclosure will readily occur to those skilled in the art after considering the specification and practicing the invention disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the present disclosure being indicated by the following claims.

[0083] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes can be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A method for monitoring the impact range of regional fracturing based on distributed fiber optic acoustic sensing, characterized in that: The method comprises: A distributed optical fiber acoustic sensor (DAS) monitoring system is pre-deployed in the fracturing area, and the DAS monitoring system collects the original signal of the fracturing area; Identifying the original signal to obtain a microseismic signal and a first arrival time of a longitudinal wave in the microseismic signal; determining the distribution location of microseismic events in the fracturing area based on the first arrival time of the longitudinal wave in the microseismic signal; The hydraulic fracturing influence range in the fracturing area is determined according to the distribution positions of the microseismic events in the fracturing area.

2. The method according to claim 1, characterized in that The process of pre-deploying the DAS monitoring system in the fracturing area includes: Acquiring construction parameters of the optical fiber holes, and constructing the optical fiber holes according to the construction parameters, wherein the construction parameters include at least quantity, spacing, angle, depth, and diameter; Obtaining a layout method for optical fibers, and laying optical fibers in the optical fiber holes according to the layout method; Obtain the placement location of the demodulator, and place the demodulator according to the placement location.

3. The method according to claim 2, characterized in that After the DAS monitoring system is determined to be deployed, the method includes: Testing the connectivity of the optical fiber using an optical time domain reflectometer; In response to the connectivity of the optical fiber passing the test, a target position is marked on the optical fiber, and the target position is set as a node position in the DAS monitoring system.

4. The method according to claim 1, wherein The identifying of the original signal to obtain the microseismic signal and the first arrival time of the longitudinal wave in the microseismic signal includes: Preprocessing the original signal to obtain a target signal; The target signal is identified based on a long-short time window algorithm to obtain the microseismic signal, and the time when the microseismic signal is first identified is used as the first arrival time of the longitudinal wave in the microseismic signal.

5. The method according to claim 1, wherein The determining of the distribution position of the microseismic event in the fracturing area based on the first arrival time of the longitudinal wave in the microseismic signal includes: The distribution positions of microseismic events in the fracturing area are determined based on the first arrival time of the longitudinal wave in the microseismic signal in combination with a Markov chain Monte Carlo algorithm.

6. The method according to claim 1, characterized in that Determining the hydraulic fracturing influence range in the fracturing area according to the distribution positions of the microseismic events in the fracturing area includes: determining a distribution density of microseismic events in the hydraulic fracturing region based on distribution locations of the microseismic events in the hydraulic fracturing region; Determining an initial hydraulic fracturing influence range in the fracturing area based on the distribution density and a preset area division method; The initial hydraulic fracturing influence range in the fracturing area is optimized to determine the hydraulic fracturing influence range in the fracturing area.

7. The method according to claim 6, characterized in that Optimizing the initial hydraulic fracturing influence range in the fracturing area to determine the hydraulic fracturing influence range in the fracturing area includes: Acquire a target area where the fracturing area is located; The hydraulic fracturing influence range that does not belong to the target area is eliminated from the initial hydraulic fracturing influence range to determine the hydraulic fracturing influence range in the fracturing area.

8. A monitoring device for regional fracturing impact range based on distributed optical fiber acoustic sensing (DAS), characterized in that: The device comprises: An acquisition module is used to pre-deploy a distributed optical fiber acoustic sensor (DAS) monitoring system in the fracturing area, and the DAS monitoring system collects the original signal of the fracturing area; an identification module, configured to identify the original signal and obtain a microseismic signal and a first arrival time of a longitudinal wave in the microseismic signal; A first determination module is configured to determine the distribution position of microseismic events in the fracturing area based on the first arrival time of the longitudinal wave in the microseismic signal; The second determining module is configured to determine the hydraulic fracturing influence range in the fracturing area based on the distribution of microseismic events in the fracturing area.

9. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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