External transaction monitoring system and method for high-sulfur-content gas well

Abstract

The invention discloses an external transaction monitoring system and method for a high-sulfur-content gas well, and the system comprises a signal receiving device which constructs a plurality of point locations in a well site where a to-be-monitored gas well is located, and each point location is used for receiving a first microseismic signal in real time, the first micro-seismic signal of each point location is obtained after a second micro-seismic signal emitted by a target source is propagated in a well site; the transaction type identification device is used for extracting signal characteristic parameters of the continuous micro-seismic signals of each point location in a specified time period so as to determine the transaction type; and the transaction area identification device is used for determining one or more effective point locations which actually receive the second micro-seismic signals and position distribution of the effective point locations according to the first micro-seismic signals of the plurality of point locations so as to determine a current transaction area. According to the invention, real-time monitoring, early warning and positioning of the external abnormal movement state of the high-sulfur-content gas well are realized.

Description

Technical Field

[0001] The invention belongs to the field of safety monitoring of high-sulfur natural gas wells, and in particular relates to an external abnormal movement monitoring system and method for high-sulfur gas wells. Background Art

[0002] With the continuous development of the national economy and the continuous optimization of the energy structure, natural gas, as a clean and environmentally friendly high-quality energy, has gradually occupied an important position in the energy structure. At the same time, natural gas consumption has also shown a trend of continuous and substantial growth. In order to ensure the supply of natural gas, my country has continued to increase its efforts in natural gas exploration and development in recent years, and has gradually developed high hydrogen sulfide gas blocks. According to statistics, my country's high-sulfur gas fields are mainly distributed in the Sichuan and Chongqing regions, which are densely populated and have complex terrain. Given the highly toxic properties of hydrogen sulfide, once hydrogen sulfide leaks during the mining, gathering, transportation, and processing stages, it will cause serious accident consequences.

[0003] First, the prior art provides an underground intrusion monitoring system based on seismic waves. The monitoring system uses the principle of seismic exploration to locate, identify and judge underground intrusion behaviors, effectively preventing illegal and criminal behaviors from underground intrusion. In addition, the monitoring system uses the theory of pattern recognition to distinguish various behaviors of moving objects and humans. After preprocessing and extracting features from the collected seismic wave signals, it matches the features of the feature library to find out the potential state of intrusion behavior and track its changing trend. Secondly, the prior art also proposes a land-air integrated warning system for key areas based on microseismic perception. The warning system is not affected by terrain, region, and space. Combined with the ant colony algorithm, it fully considers the threat coefficient, mobility, and reaction time of the intrusion target, realizes real-time optimization of the warning plan, completes the effective identification, tracking, expulsion, and control of the intrusion target, and extends the effective working time of the entire system in the unmanned state. It realizes full-time uninterrupted intelligent monitoring of key areas, and can use the original wired video surveillance system to enhance the monitoring capability of key areas. In addition, the prior art also provides an intrusion monitoring device and monitoring system for field oil and gas pipelines, which sends an optical signal to an optical fiber through a laser generating device and transmits it to a photoelectric conversion device through an optical coupler. The photoelectric conversion device converts the optical signal into an electrical signal and sends it to an acquisition board. The acquisition board transmits the acquired signal to a main control board. The main control board identifies the signal and determines whether the monitored oil and gas pipeline is vibrated or damaged, thereby realizing the detection of the pipeline status.

[0004] Nowadays, more than 90% of the damage suffered by my country's oil and gas facilities comes from external changes (i.e., human intrusion). Although people's safety awareness and overall quality have been greatly improved, safety accidents caused by drilling and stealing oil or gas still occur from time to time. The monitoring means for production and safety accidents caused by external changes are currently mainly completed by video monitoring of personnel on duty or infrared camera recognition. Among them, video monitoring of personnel on duty requires a lot of manpower and material resources, and the monitoring effect is affected by factors such as the sense of responsibility and attention of the personnel on duty, and it is easy to miss reports; infrared cameras can monitor abnormal heat bodies, but cannot accurately identify every intruder wearing professional protective equipment. In addition, in the process of realizing the present invention, the inventor found that the aforementioned prior art all adopted different principles to conduct safety monitoring of specific places, but did not explore the external intrusion that high-sulfur gas wells may face, and was not targeted enough. Therefore, it is very necessary to study the technology of monitoring the external environmental safety status of high-sulfur gas wells, early warning and locating intruders. Summary of the invention

[0005] In order to solve the above problems, an embodiment of the present invention provides an external abnormal movement monitoring system for high-sulfur gas wells, including: a signal receiving device, which constructs multiple points at the well site where the gas well to be monitored is located, each point is used to receive a first microseismic signal in real time, and the first microseismic signal at each point is obtained after the second microseismic signal emitted by the target source propagates in the well site; an abnormal movement type identification device, which is used to extract signal characteristic parameters of the continuous microseismic signal of each point in a specified time period, so as to determine the abnormal movement type; an abnormal movement area identification device, which is used to determine one or more valid points and their position distribution that actually receive the second microseismic signal based on the first microseismic signals of the multiple points, so as to determine the current abnormal movement area.

[0006] Preferably, the plurality of points are evenly distributed on a circle with the center of the gas well to be monitored as the center, wherein the position of each point is determined according to an optimal monitoring distance of each point.

[0007] Preferably, the optimal monitoring distance includes: an optimal non-drilling theft monitoring distance and an optimal drilling theft monitoring distance, wherein the optimal non-drilling theft monitoring distance / the optimal drilling theft monitoring distance are obtained by conducting a walking test / excavation test using a microseismic sensor arranged at any point in the well site.

[0008] Preferably, the multiple points are at least three points, wherein if the well field where the gas well to be monitored is located is a rectangular well field, a four-point point arrangement method is adopted; or if the well field where the gas well to be monitored is located is a triangular well field, a three-point point arrangement method is adopted.

[0009] Preferably, the signal receiving device comprises: a plurality of microseismic sensors respectively arranged at different points, wherein the microseismic sensors are three-component microseismic sensors that meet specific technical parameter conditions, wherein the specific technical parameter conditions include but are not limited to: a frequency bandwidth of 1 to 240 Hz; a GNSS timing accuracy of + / -10 μs; a gain accuracy of 0.1%; and

[0010] The sampling interval is less than or equal to 4ms.

[0011] Preferably, the abnormal movement type identification device includes: a signal analysis unit, which is used to extract the receiving time and amplitude information in the continuous microseismic signal of each point as the signal characteristic parameters to obtain the amplitude change characteristics and signal receiving time interval of each continuous microseismic signal; an abnormal movement type generation unit, which is used to determine the current abnormal movement type according to the amplitude change characteristics and the signal receiving time interval, wherein if the amplitude gradually increases, the current abnormal movement type is determined to be non-perforation theft, or if the amplitude remains unchanged and each signal receiving time interval is the same, the current abnormal movement type is determined to be perforation theft.

[0012] Preferably, the abnormal movement area identification device includes: an abnormal movement area division unit, which is used to plan multiple groups of point combinations with different number and positions of points capable of receiving the second microseismic signal, and match the abnormal movement area for each group of point combinations; an abnormal movement area generation unit, which is used to identify the number and positions of valid points that receive the second microseismic signal in real time based on the first microseismic signal of each point, determine the corresponding point combination and retrieve the abnormal movement area matching the current point combination as the current abnormal movement area.

[0013] Preferably, the external abnormal movement monitoring system further comprises: an abnormal movement tracking device, which is used to collect the determined abnormal movement area in real time, and determine the moving path of the abnormal movement area according to the generation time of the abnormal movement area, so as to track the abnormal movement situation.

[0014] Preferably, the abnormal area identification device is also used to calculate the coordinates of the current abnormal area using the center of the gas well to be monitored as the coordinate origin when the number of points that actually receive the second microseismic signal is greater than or equal to 3, using the distance between each valid point and the abnormal area and the time difference between any two valid points receiving the microseismic signal, combined with the propagation distance of the second microseismic signal in the well field where the current gas well to be monitored is located, so as to accurately locate the current abnormal area.

[0015] Preferably, the abnormal movement area identification device includes: a propagation speed calculation unit, which is used to arrange microseismic sensors at any two points in the well site to receive the first microseismic signal of the experimental target source, and use the signal reception time difference between each microseismic sensor and the distance between the experimental target source and each microseismic sensor to calculate the propagation speed of the microseismic signal in the well site where the gas well to be monitored is currently located, so as to obtain the propagation distance of the second microseismic signal in the well site where the gas well to be monitored is currently located.

[0016] Preferably, the propagation velocity calculation unit is further used to calculate the difference in distance between the experimental target source and the microseismic sensors at any two points, and use the ratio of the distance difference to the signal reception time difference as the propagation velocity.

[0017] In addition, the present invention also proposes a method for monitoring external abnormal movements of high-sulfur gas wells, which utilizes the external abnormal movement monitoring system for high-sulfur gas wells described in the present invention to realize monitoring of external abnormal movements, and the external abnormal movement monitoring method includes: using a signal receiving device to construct multiple points in the well field where the gas well to be monitored is located, so that each point can receive a first microseismic signal in real time, wherein the first microseismic signal of each point is obtained by a second microseismic signal emitted by a target source after propagation in the well field; extracting the signal characteristic parameters of the continuous microseismic signal of each point in a specified time period through an abnormal movement type identification device, thereby determining the abnormal movement type; the abnormal movement area identification device determines one or more valid points and their position distribution that actually receive the second microseismic signal based on the first microseismic signals of the multiple points, thereby determining the current abnormal movement area.

[0018] Compared with the prior art, one or more embodiments of the above scheme may have the following advantages or beneficial effects:

[0019] The present invention proposes a system and method for monitoring external abnormal movements of high-sulfur gas wells. The signal receiving device of the system constructs multiple points at the well site where the gas well to be monitored is located, and collects microseismic signals related to abnormal activities (for example, intrusion by outsiders) at each point; the abnormal movement type identification device determines the abnormal movement type according to the characteristic parameters of the microseismic signal; the abnormal movement area identification device determines the current abnormal movement area according to the effective points and position distribution of the microseismic signals actually collected. The present invention proposes a reasonable and effective method for monitoring, warning and locating external abnormal movements of high-sulfur gas wells based on microseismic signals, which effectively expands the external abnormal movement monitoring range of high-sulfur gas wells, and can identify the abnormal movement type and locate the abnormal movement position.

[0020] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0022] Figure 1 Schematic diagram of the overall structure of an external abnormal movement monitoring system for high-sulfur gas wells according to an embodiment of the present application.

[0023] Figure 2 Schematic diagram of microseismic signal propagation of an external abnormality monitoring system for high-sulfur gas wells according to an embodiment of the present application.

[0024] Figure 3 Schematic diagram of propagation velocity test of an external abnormality monitoring system for high-sulfur gas wells according to an embodiment of the present application.

[0025] Figure 4 Schematic diagram of the optimal monitoring distance test for the external abnormality monitoring system for high-sulfur gas wells according to an embodiment of the present application.

[0026] Figure 5 This is a schematic diagram of the four-point layout of an external abnormal movement monitoring system for a high-sulfur gas well according to an embodiment of the present application.

[0027] Figure 6 Schematic diagram of the four-point precise positioning of the external abnormal movement monitoring system for high-sulfur gas wells according to an embodiment of the present application.

[0028] Figure 7 This is a schematic diagram of the three-point layout of an external abnormal movement monitoring system for a high-sulfur gas well according to an embodiment of the present application.

[0029] Figure 8 This is a step diagram of a method for monitoring external abnormalities in a high-sulfur gas well according to an embodiment of the present application. DETAILED DESCRIPTION

[0030] The following will describe the implementation methods of the present invention in detail with reference to the accompanying drawings and embodiments, so that the implementation process of how the present invention applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly. It should be noted that as long as there is no conflict, the various embodiments of the present invention and the various features in the embodiments can be combined with each other, and the technical solutions formed are all within the protection scope of the present invention.

[0031] In addition, the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be performed in an order different from that shown here.

[0032] With the continuous development of the national economy and the continuous optimization of the energy structure, natural gas, as a clean and environmentally friendly high-quality energy, has gradually occupied an important position in the energy structure. At the same time, natural gas consumption has also shown a trend of continuous and substantial growth. In order to ensure the supply of natural gas, my country has continued to increase its efforts in natural gas exploration and development in recent years, and has gradually developed high hydrogen sulfide gas blocks. According to statistics, my country's high-sulfur gas fields are mainly distributed in the Sichuan and Chongqing regions, which are densely populated and have complex terrain. Given the highly toxic properties of hydrogen sulfide, once hydrogen sulfide leaks during the mining, gathering, transportation, and processing stages, it will cause serious accident consequences.

[0033] First, the prior art provides an underground intrusion monitoring system based on seismic waves. The monitoring system uses the principle of seismic exploration to locate, identify and judge underground intrusion behaviors, effectively preventing illegal and criminal behaviors from underground intrusion. In addition, the monitoring system uses the theory of pattern recognition to distinguish various behaviors of moving objects and humans. After preprocessing and extracting features from the collected seismic wave signals, it matches the features of the feature library to find out the potential state of intrusion behavior and track its changing trend. Secondly, the prior art also proposes a land-air integrated warning system for key areas based on microseismic perception. The warning system is not affected by terrain, region, and space. Combined with the ant colony algorithm, it fully considers the threat coefficient, mobility, and reaction time of the intrusion target, realizes real-time optimization of the warning plan, completes the effective identification, tracking, expulsion, and control of the intrusion target, and extends the effective working time of the entire system in the unmanned state. It realizes full-time uninterrupted intelligent monitoring of key areas, and can use the original wired video surveillance system to enhance the monitoring capability of key areas. In addition, the prior art also provides an intrusion monitoring device and monitoring system for field oil and gas pipelines, which sends an optical signal to an optical fiber through a laser generating device and transmits it to a photoelectric conversion device through an optical coupler. The photoelectric conversion device converts the optical signal into an electrical signal and sends it to an acquisition board. The acquisition board transmits the acquired signal to a main control board. The main control board identifies the signal and determines whether the monitored oil and gas pipeline is vibrated or damaged, thereby realizing the detection of the pipeline status.

[0034] Nowadays, more than 90% of the damage suffered by my country's oil and gas facilities comes from external changes (i.e., human intrusion). Although people's safety awareness and overall quality have been greatly improved, safety accidents caused by drilling and stealing oil or gas still occur from time to time. The monitoring means for production and safety accidents caused by external changes are currently mainly completed by video monitoring of personnel on duty or infrared camera recognition. Among them, video monitoring of personnel on duty requires a lot of manpower and material resources, and the monitoring effect is affected by factors such as the sense of responsibility and attention of the personnel on duty, and it is easy to miss reports; infrared cameras can monitor abnormal heat bodies, but cannot accurately identify every intruder wearing professional protective equipment. In addition, in the process of realizing the present invention, the inventor found that the aforementioned prior art all adopted different principles to conduct safety monitoring of specific places, but did not explore the external intrusion that high-sulfur gas wells may face, and was not targeted enough. Therefore, it is very necessary to study the technology of monitoring the external environmental safety status of high-sulfur gas wells, early warning and locating intruders.

[0035] Therefore, in order to solve the above problems, the present invention proposes a system and method for monitoring external abnormal movements of high-sulfur gas wells. The signal receiving device of the system constructs multiple points at the well site where the gas well to be monitored is located, and collects microseismic signals related to abnormal activities (for example, intrusion by outsiders) at each point; the abnormal movement type identification device determines the abnormal movement type according to the characteristic parameters of the microseismic signal; the abnormal movement area identification device determines the current abnormal movement area according to the effective points and their position distribution of the microseismic signals actually collected. The present invention proposes a reasonable and effective method for monitoring, warning and locating external abnormal movements of high-sulfur gas wells based on microseismic signals, which effectively expands the external abnormal movement monitoring range of high-sulfur gas wells, and can identify the abnormal movement type and locate the abnormal movement position.

[0036] Embodiment 1

[0037] Figure 1 The overall structure diagram of the external abnormal movement monitoring system for high sulfur gas wells according to the embodiment of the present application is shown below. Figure 1 The structure of the external abnormal movement monitoring system for high-sulfur gas wells described in the present invention is described in detail.

[0038] In this embodiment, the external abnormal movement monitoring system for high-sulfur gas wells includes at least: a signal receiving device 11, an abnormal movement type identification device 12 and an abnormal movement area identification device 13. The signal receiving device 11 constructs multiple points at the well site where the gas well to be monitored is located, and each point is used to receive the first microseismic signal in real time. The first microseismic signal at each point is obtained after the second microseismic signal emitted by the target source propagates in the well site. The abnormal movement type identification device 12 extracts the signal characteristic parameters of the continuous microseismic signal of each point constructed by the signal receiving device 11 in a specified time period, thereby determining the abnormal movement type. The abnormal movement area identification device 13 determines one or more valid points and their position distribution that actually receive the second microseismic signal based on the first microseismic signals of the multiple points constructed by the signal receiving device 11, thereby determining the current abnormal movement area.

[0039] The signal receiving device 11 is constructed with multiple points at the well site where the gas well to be monitored is located, and each point is used to receive the first microseismic signal in real time. The first microseismic signal at each point is obtained by the second microseismic signal emitted by the target source after propagation in the well site. In order to solve the problems of monitoring blind spots and being greatly affected by the on-duty personnel in the gas well safety monitoring method using video monitoring and infrared camera recognition of personnel on duty in practical applications, the present invention realizes real-time monitoring of the external abnormal state of the high-sulfur gas well based on the microseismic signal related to the abnormal activity. Specifically, the signal receiving device 11 is constructed with multiple points at the well site where the gas well to be monitored is located, and receives the microseismic signal related to the external abnormal activity (for example: intrusion by outsiders) in real time at each point, so as to realize the real-time monitoring of the external abnormal state of the high-sulfur gas well according to the received microseismic signal. Among them, when the external abnormal activity occurs, the synchronous microseismic signal generated by the abnormal activity is the second microseismic signal emitted by the target source, and the second microseismic signal is received by the corresponding point after propagation in the well site, and the microseismic signal received by the corresponding point is the first microseismic signal.

[0040] Any signal will attenuate in the propagation medium as the propagation time increases during the propagation process. In addition, my country's high-sulfur gas wells are mainly distributed in the Sichuan-Chongqing region and the Ordos Basin region. The surface layers are mainly soft soil layers and dense sand layers, respectively. The propagation speed and propagation distance of microseismic signals under different surface characteristics are also different. Therefore, before the signal receiving device 11 constructs multiple points in the well field where the gas well to be monitored is located, it is necessary to clarify the optimal monitoring range of the selected microseismic sensor under different surface conditions. Therefore, this embodiment first determines the surface characteristics of the well field where the gas well to be monitored is located, and then obtains the optimal monitoring distance of the microseismic sensor under the current surface characteristics. At the same time, my country's high-sulfur gas fields are mainly distributed in the Sichuan and Chongqing regions with complex terrain and dense population. Gas wells are mainly distributed halfway up the mountain or on the top of the mountain. There are only dedicated roads to reach the well site. Since there are clear boundaries and walls around the gas well site, there is almost no situation where vehicles rush in or large-scale excavators drive in to cause damage. The surrounding area is densely populated and there is a lot of agricultural land, so there are only two types of abnormal activities at the gas well site: people approaching the gas well to steal natural gas through the sampling port at the wellhead (ie: non-drilling theft) and people digging up the soil around the wellhead and drilling holes in the pipeline to steal natural gas (ie: drilling theft).

[0041] Furthermore, the optimal monitoring distance of the present invention includes the optimal non-drilling theft monitoring distance and the optimal drilling theft monitoring distance, wherein the optimal non-drilling theft monitoring distance / optimal drilling theft monitoring distance is obtained by performing a walking test / digging test using a microseismic sensor arranged at any point in the well site. Specifically, in this embodiment, a microseismic sensor for testing the optimal monitoring distance (the same as the one actually used to receive microseismic signals) is buried beneath the surface at a first specified burial depth at any location in the well site where the gas well to be monitored is located. Afterwards, multiple test distances are set, and corresponding test points are determined according to each test distance, so that the distance between each test point and the microseismic sensor currently used to test the optimal monitoring distance meets the set test distance. Finally, by stepping in place and digging with a hoe at each test point, data such as Figure 4 The microseismic signal of the stepping test shown on the left and the microseismic signal of the hoe digging test shown on the right ( Figure 4 Schematic diagram of the optimal monitoring distance test for the external abnormal movement monitoring system for high-sulfur gas wells according to the embodiment of the present application). When the test microseismic signal is obvious and the waveform is clear, and the moment of stepping on the spot and digging with a hoe can be clearly distinguished, the corresponding test distance is determined to be the optimal non-drilling theft monitoring distance and the optimal drilling theft monitoring distance of the microseismic sensor under such surface conditions as shown in Table 1:

[0042] Table 1 Optimal monitoring distance

[0043] Soft soil layer Compacted sand layer Marking the Spot (Best Non-Drilling Theft Detection Distance) a1 a2 Hoe digging (optimal drilling and theft monitoring distance) b1 b2

[0044] In a specific embodiment of the present application, the first designated burial depth is preferably 30 cm, and the test distance is preferably 5 m, 10 m, 20 m, 30 m, and 50 m. It should be noted that the present invention does not specifically limit the first designated burial depth and the test distance, and those skilled in the art can set them according to the signal acquisition sensitivity, abnormal movement type, and surface characteristics of the microseismic sensor actually selected for receiving microseismic signals.

[0045] Further, the multiple points constructed by the signal receiving device 11 are evenly distributed on the circumference of the circle with the center of the gas well to be monitored as the center, wherein the position of each point is determined according to the optimal monitoring distance of each point. Specifically, based on the above analysis, it can be known that there are only two types of abnormalities in the gas well site: personnel approaching the gas well to steal natural gas through the sampling port at the wellhead (i.e., non-drilling theft) and digging holes in the pipeline around the wellhead to steal natural gas (i.e., drilling theft). In other words, the abnormality caused by theft must surround the gas well to be monitored, so this embodiment evenly distributes multiple points on the circumference of the circle with the center of the gas well to be monitored as the center, effectively ensuring comprehensive monitoring of abnormal conditions. In a specific embodiment of the present application, it is assumed that the optimal non-drilling theft monitoring distance and the optimal drilling theft monitoring distance are a and b respectively. Generally speaking, there is a size relationship of a<b<2a between the optimal non-drilling theft monitoring distance and the optimal drilling theft monitoring distance. Therefore, this embodiment determines the position of each point as 0.5a away from the wellhead of the gas well to be monitored, so that each point has the ability to fully monitor the abnormal movements around the well. Furthermore, given that the multiple points constructed by the signal receiving device 11 have the ability to fully monitor the abnormal movements around the well, the reliability of monitoring the abnormal movements around the gas well to be monitored is effectively improved.

[0046] The multiple points described in the present invention are at least three points, wherein if the well field where the gas well to be monitored is located is a rectangular well field, a four-point point arrangement method is adopted; or if the well field where the gas well to be monitored is a triangular well field, a three-point point arrangement method is adopted. In the embodiment of the present application, the line connecting the adjacent points and the center of the gas well in the four-point point arrangement method forms an angle of 45°.

[0047] Furthermore, the signal receiving device 11 includes a plurality of microseismic sensors respectively arranged at different points. In practical applications, the synchronous microseismic signals generated by the abnormal movement are generally weak and have a low frequency range, so it is necessary to select a low-frequency microseismic sensor with high sensitivity to meet the acquisition requirements of the target microseismic signal. In an embodiment of the present application, a plurality of microseismic sensors are respectively arranged at different points, and a microseismic sensor is arranged at each point. The microseismic sensor adopts a three-component microseismic sensor, and the three-component microseismic sensor meets the following specific technical parameter conditions, so that the selected three-component microseismic sensor can collect the target microseismic signal. Among them, the specific technical parameter conditions include but are not limited to: the frequency bandwidth is 1 to 240 Hz; the GNSS timing accuracy is + / -10μs; the gain accuracy is 0.1%; and the sampling interval is less than or equal to 4ms.

[0048] The abnormal movement type identification device 12 of the present invention is used to extract the signal characteristic parameters of the continuous microseismic signal of each point in a specified period of time, so as to determine the abnormal movement type. Figure 2 Schematic diagram of microseismic signal propagation for an external abnormality monitoring system for a high-sulfur gas well according to an embodiment of the present application. Figure 2 As shown, in actual application, both non-drilling theft related to personnel walking and drilling theft related to personnel digging will exert force on the ground surface to generate vibration and form a second microseismic signal, and then the second microseismic signal propagates to a distance to form a first microseismic signal received by the signal receiving device 11, and is captured by the microseismic sensor buried around the gas well to be monitored. When a person walks, his footsteps interact with the ground surface. The footsteps act as a point source of vibration. As the person moves, the amplitude of the first microseismic signal will gradually increase under the condition of constant speed. The position and speed of manual digging are relatively fixed, so the amplitude and time interval of the first microseismic signal are relatively fixed, and the amplitude is significantly higher than that of personnel walking under the same distance. It can be seen that the abnormal movement type identification device 12 of the present invention obtains the amplitude change trend and the change trend of each microseismic signal receiving time interval under the specified time period by extracting the signal characteristic parameters of the continuous microseismic signal of each point in the specified time period, thereby realizing accurate identification of the abnormal movement type.

[0049] Furthermore, the abnormal movement type identification device 12 includes: a signal analysis unit and an abnormal movement type generation unit. The signal analysis unit is used to extract the receiving time and amplitude information in the continuous microseismic signal of each point as signal characteristic parameters to obtain the amplitude change characteristics and signal receiving time interval of each continuous microseismic signal; the abnormal movement type generation unit is used to determine the current abnormal movement type according to the amplitude change characteristics and signal receiving time interval. Specifically, the signal analysis unit extracts the receiving time and amplitude information in the continuous microseismic signal of each point as signal characteristic parameters, and calculates the receiving time interval between adjacent signals using each receiving time, and calculates the amplitude difference between adjacent signals using the amplitude information of each signal, so as to obtain the amplitude change characteristics and signal receiving time interval of each continuous microseismic signal. At this time, the abnormal movement type generation unit determines the current abnormal movement type according to the amplitude change characteristics and signal receiving time interval calculated by the signal analysis unit. According to the above analysis, if the amplitude of continuous microseismic signals gradually increases, the current anomaly type is determined to be non-perforation theft, or if the amplitude of continuous microseismic signals remains unchanged and the time interval for receiving each signal is the same, the current anomaly type is determined to be perforation theft.

[0050] Furthermore, the abnormal movement area identification device 13 is used to determine one or more valid points that actually receive the second microseismic signal and their position distribution based on the first microseismic signals of multiple points, so as to determine the current abnormal movement area. After the second microseismic signal starts to propagate, due to the different distances between the target source and different points, there may be one or more points that cannot receive the first microseismic signal. In other words, the number and position distribution of the points that receive the first microseismic signal are related to the position of the target source. Therefore, this embodiment takes the points that receive the first microseismic signal belonging to the same target source (one or more points that actually receive the second microseismic signal) as valid points, thereby achieving the purpose of determining the current abnormal movement area based on one or more valid points that actually receive the second microseismic signal and their position distribution.

[0051] The abnormal area identification device 13 includes: an abnormal area division unit and an abnormal area generation unit. Among them, the abnormal area division unit is used to plan out multiple groups of point combinations with different numbers and positions of points that have the ability to receive the second microseismic signal, and match the abnormal area for each group of point combinations. The abnormal area generation unit is used to identify the number and position of valid points that receive the second microseismic signal in real time based on the first microseismic signal of each point, determine the corresponding point combination and call the abnormal area that matches the current point combination as the current abnormal area. In an embodiment of the present application, the abnormal area division unit plans out multiple groups of point combinations with different numbers and positions of points that have the ability to receive the second microseismic signal, and matches the abnormal area for each group of point combinations to obtain a mapping relationship between the point combination and the abnormal area. Furthermore, the abnormal movement area generation unit determines the actual point combination based on the point that receives the first microseismic signal, identifies the number and positions of valid points that receive the second microseismic signal in real time, and then uses the mapping relationship between the point combination and the abnormal movement area to retrieve the abnormal movement area that matches the current actual point combination. The abnormal movement area is the current abnormal movement area.

[0052] Next, refer to Figure 5 and Table 2, taking the four-point point arrangement method as an example, the functions of the abnormal area division unit and the abnormal area generation unit are described in detail ( Figure 5 Schematic diagram of the four-point layout of the external abnormal movement monitoring system for high-sulfur gas wells according to an embodiment of the present application).

[0053] Table 2: Mapping relationship between a point combination and the abnormality occurrence area in the embodiment

[0054]

[0055]

[0056] In the process of planning multiple groups of point combinations with different numbers and positions of points capable of receiving the second microseismic signal by the abnormal area division unit, and matching the abnormal area for each group of point combinations, refer to Figure 5 Based on the four-point point arrangement method, the optimal non-perforation theft monitoring distance and the optimal perforation theft monitoring distance are recorded as a and b, respectively, thus forming the following four monitoring barriers around the gas well to be monitored, namely: 0~0.5a, 0.5a~a, a~1.5a and 1.5a~0.5a+b.

[0057] When the distance between the abnormal movement and the gas wellhead is greater than 0.5a+b, the distance is too far, and it is impossible to steal natural gas by digging a surface pipeline borehole (i.e., it is impossible to steal by drilling), and in this case, drilling theft can be monitored without focus. When the distance between the abnormal movement and the gas wellhead is greater than or equal to 1.5a (outside or at the edge of area C or D), the abnormal movement is far from the wellhead, and it is impossible to steal natural gas through the wellhead sampling port (i.e., non-drilling theft), and in this case, non-drilling theft can be monitored without focus.

[0058] When the distance between the abnormal movement and the gas wellhead is 1.5a~0.5a+b (in the E or F area), the drilling and theft monitoring area has been entered. Under the condition that there is a microseismic sensor to realize monitoring and early warning (the current point combination with the ability to receive the second microseismic signal is a point combination that only includes one microseismic sensor), it means that personnel are conducting exploratory excavation in the E or F area, that is, the area where the abnormal movement occurs is the E or F area.

[0059] When the distance between the abnormal movement and the gas wellhead is less than 1.5a (within area A, B, C or D), it is obvious that the drilling and theft monitoring area has been entered. Under the condition that there are three or more microseismic sensors to realize monitoring and early warning (the current point combination capable of receiving the second microseismic signal is a point combination including three or more microseismic sensors), it means that personnel are conducting exploratory excavation in area A, B, C or D, that is, the area where the abnormal movement occurs is area A, B, C or D.

[0060] When the distance between the anomaly and the gas wellhead is 1a to 1.5a (in area C or D), it has entered the effective monitoring range of non-drilling theft. Under the condition that there is one microseismic sensor to realize monitoring and early warning (the current point combination with the ability to receive the second microseismic signal is a point combination that only includes one microseismic sensor), it means that the person has walked into area D from the southwest, northwest, southeast or northeast. Under the condition that there are two microseismic sensors to realize monitoring and early warning (the current point combination with the ability to receive the second microseismic signal is a point combination that includes two microseismic sensors), it means that the person has walked into area C from the south, north, east or west.

[0061] When the distance between the abnormal movement and the gas wellhead is between 0.5a and 1a, most of the activities of the intruders will be completed in area B. Under the condition that there are three microseismic sensors to realize monitoring and early warning (the current point combination with the ability to receive the second microseismic signal is a point combination including three microseismic sensors), it means that the personnel have entered area D. Or a small amount of activities of the intruders will be completed in area C in the four directions of due east, due west, due south or due north. Under the condition that there are two microseismic sensors to realize monitoring and early warning (the current point combination with the ability to receive the second microseismic signal is a point combination including two microseismic sensors), it means that the personnel have entered area C.

[0062] When the distance between the abnormal movement and the gas wellhead is between 0 and 0.5a, and there are four microseismic sensors to realize monitoring and early warning (the current point combination capable of receiving the second microseismic signal is a point combination including four microseismic sensors), it means that the personnel are in area A.

[0063] In summary, the four-point point arrangement method described in the present invention effectively increases the monitoring range (the diameter of the perforation theft monitoring range is expanded from a to 1.5a; the diameter of the non-perforation theft monitoring range is expanded from b to 0.5a+b) compared to the monitoring method of only setting a single microseismic sensor. Moreover, when the current point combination includes one or more points, the regional positioning within the full monitoring range of the gas well to be monitored is achieved.

[0064] Furthermore, the external abnormal movement monitoring system described in the present invention also includes an abnormal movement tracking device. The abnormal movement tracking device is used to collect the determined abnormal movement area in real time, and determine the moving path of the abnormal movement area according to the generation time of the abnormal movement area, so as to track the abnormal situation. The four-point point arrangement method described in the present invention also roughly locates the abnormal movement in the entire area through regional division, the number of sensor alarms (the number of effective points) and the location of the alarm sensor (the location of the effective point), and then determines its moving route. The abnormal movement tracking device collects the determined abnormal movement area in real time, and generates a moving route map related to the abnormal movement according to the generation time of the abnormal movement area, so as to determine the moving path of the abnormal movement area, thereby achieving the purpose of tracking the abnormal situation. It can be seen that the present invention realizes the effective tracking of the abnormal position and moving route based on the regional positioning within the full monitoring range of the gas well to be monitored.

[0065] Further, based on the regional positioning within the full monitoring range of the gas well to be monitored when the current point combination includes one or more points, the abnormal area identification device 13 of the present invention is also used to calculate the coordinates of the current abnormal area by using the distance between each effective point and the abnormal area, and the time difference between any two effective points receiving the microseismic signal, combined with the propagation distance of the second microseismic signal in the well field where the gas well to be monitored is currently located, when the number of points that actually receive the second microseismic signal is greater than or equal to 3, taking the center of the gas well to be monitored as the coordinate origin, and combining the propagation distance of the second microseismic signal in the well field where the gas well to be monitored is currently located, so as to accurately locate the current abnormal area.

[0066] In actual applications, one or two effective points cannot accurately locate a certain point, but three or more effective points (i.e., the number of points that actually receive the second microseismic signal is greater than or equal to 3) have the ability to accurately locate external abnormalities. In other words, when the abnormality type is perforation theft and the abnormal position is in the A, B, C or D area, positioning can be achieved; or when the abnormality type is non-perforation theft and the abnormal position is in the A or B area, positioning can be achieved. Figure 6This is a schematic diagram of the four-point precise positioning of the external abnormal movement monitoring system for high-sulfur gas wells in an embodiment of the present application. Figure 6 , it is known that the distance between the effective point and the wellhead of the gas well to be monitored is 0.5a. At this time, the center of the gas well to be monitored is taken as the coordinate origin and the coordinates of the three effective points are marked as The coordinates of the current abnormal position are marked as (x, y), and the coordinates of the current abnormal position are calculated using the following expression, so as to achieve accurate positioning of the current abnormal position. Further, based on the coordinate changes that match the positioning results, the moving route is accurately identified, so that targeted control can be carried out:

[0067]

[0068]

[0069] Among them, L1, L2 and L3 represent the distance between the abnormal position and each effective point, V represents the propagation distance of the microseismic signal under the current surface conditions, Δt 21 , Δt 31 and Δt 23 They represent the time difference of acquiring signals between effective points, a represents the optimal non-perforation theft monitoring distance, t1, t2 and t3 represent the signal acquisition time of different effective points, x represents the horizontal coordinate of the abnormal position, and y represents the vertical coordinate of the abnormal position.

[0070] In a specific embodiment of the present application, if the current anomaly is in the monitoring overlap area of ​​four valid points, three valid points that receive the strongest microseismic signals can be selected to accurately locate the current anomaly.

[0071] Furthermore, the abnormal region identification device 13 includes a propagation velocity calculation unit. The propagation velocity calculation unit is used to arrange microseismic sensors at any two points in the well site to receive the first microseismic signal of the experimental target source, and use the signal reception time difference between each microseismic sensor and the distance between the experimental target source and each microseismic sensor to calculate the propagation velocity of the microseismic signal in the well site where the gas well to be monitored is currently located, so as to obtain the propagation distance of the second microseismic signal in the well site where the gas well to be monitored is currently located. The size of a single well site is mostly 30m*40m, and the gas well is located in the center of the well site. Figure 3 This is a schematic diagram of the propagation speed test of the external abnormality monitoring system for high-sulfur gas wells according to an embodiment of the present application. Figure 3In a specific embodiment of the present application, two microseismic sensors for receiving the first microseismic signal of the experimental target source (the same as the microseismic signal actually received) are buried under the ground surface at any two points in the well field where the gas well to be monitored is located according to the second specified burial depth. Then, a building red brick is released at a height of 50 cm from the ground surface at point No. 1 to ensure that the maximum surface area of ​​the red brick is vertically in contact with the ground, and the signal reception time difference between the two sensors for receiving the microseismic signal is calculated. Finally, the signal reception time difference and the distance between the experimental target source (the contact position of the red brick with the ground) and each microseismic sensor are used to calculate the propagation speed of the microseismic signal in the well field where the gas well to be monitored is located (according to the above, this embodiment uses the microseismic signal propagated in the well field where the gas well to be monitored is located as the second microseismic signal, so the propagation speed here is the propagation speed of the second microseismic signal) to obtain the propagation distance of the second microseismic signal in the well field where the current gas well to be monitored is located.

[0072] Continue to refer to Figure 3 In a specific embodiment of the present application, the propagation velocity of the microseismic signal is measured at points 2 to 6, respectively, and the average value of the six test results is used as the propagation velocity of the microseismic signal in the well field where the gas well to be monitored is located, thereby effectively ensuring the reliability of the propagation velocity calculation results.

[0073] In a specific embodiment of the present application, the second designated burial depth is preferably 30 cm, and the distance between any two points is preferably 40 m. It should be noted that the present invention does not specifically limit the second designated burial depth and the distance between the two points, and those skilled in the art can set them according to the signal acquisition sensitivity, abnormal movement type, and surface characteristics of the microseismic sensor actually selected for receiving microseismic signals.

[0074] Furthermore, the propagation velocity calculation unit is also used to calculate the difference in distance between the experimental target source and the microseismic sensors at any two points (the difference in distance between the two sensors and the brick ground), and use the ratio of the distance difference to the signal reception time difference as the propagation velocity.

[0075] In addition, the point layout method can be adjusted according to the shape of the gas well site, the main abnormal situation, and the investment budget. If the monitoring budget is insufficient, the gas well site is triangular or the abnormal pattern is single, the following can be used Figure 7 The three-point layout method shown ( Figure 7 The three-point layout diagram of the external abnormal movement monitoring system for high-sulfur gas wells in the embodiment of the present application is used to effectively reduce the monitoring cost. At this time, if the abnormal movement is in area B or C, the area can be roughly located; if the abnormal movement is in area A, it can be accurately located.

[0076] Embodiment 2

[0077] In a specific embodiment of the present application, the gas well to be monitored is located in a rectangular well field area in Sichuan. The rainfall in Sichuan during the flood season is heavy, and the surface soil is mainly soft.

[0078] Next, four points are constructed in the well site where the gas well to be monitored is located according to the four-point point arrangement method described in Example 1, and according to the propagation velocity measurement method described in Example 1, an open space with surface conditions consistent with those around the gas wellhead is selected around the well site, and two microseismic sensors are buried 30 cm below the surface, and the straight-line distance between the two microseismic sensors is 40 m. Afterwards, a building red brick is released at a height of 50 cm from the surface at point 1 to ensure that the maximum surface area of ​​the red brick vertically contacts the ground, and the time difference between the two sensors detecting the microseismic signal is recorded. The microseismic signal propagation velocity is the ratio of the difference in the distance between the two sensors and the brick-falling ground to the difference in the time of receiving the signal. Subsequently, the microseismic signal propagation velocity is measured at points 2 to 6 to obtain the measurement results shown in Table 3. The average value of the 6 test results can be used as the propagation velocity under the surface conditions.

[0079] Table 3 Propagation velocity measurement results of Example 2

[0080] Measuring point Measuring speed 1 131.3 2 132.9 3 128.4 4 119.6 5 130.6 6 129.8 average value 128.8

[0081] Next, according to the optimal monitoring distance calculation method described in Example 1, a microseismic sensor was buried 30 cm below the surface, and the microseismic sensors were stepped on the spot and dug with a hoe at 5 m, 10 m, 20 m, 30 m, and 50 m away from the microseismic sensor, and the corresponding microseismic signals were collected. After testing, it was found that the optimal non-drilling theft monitoring distance of the microseismic sensor under such surface conditions was 30 m, and the optimal drilling theft monitoring distance was 50 m.

[0082] Further, according to Figure 5 According to the point distribution method shown in FIG4 , four microseismic sensors are shallowly buried symmetrically at 45° at the wellhead of the gas well to be monitored. The distance between the microseismic sensors and the wellhead is 15 m, thereby forming the following four monitoring barriers around the well to be monitored, namely: 0-15 m, 15-30 m, 30-45 m and 45 m-65 m. The mapping relationship between the abnormal movement type and the abnormal movement occurrence area, as well as the mapping relationship between the point combination and the abnormal movement occurrence area, as shown in Tables 4 and 5, are obtained.

[0083] Table 4: Mapping relationship between change types and change occurrence areas in Example 2

[0084]

[0085]

[0086] Table 5: Mapping relationship between point combinations and abnormality occurrence areas in Example 2

[0087]

[0088] Finally, according to the precise positioning conditions and positioning methods of the abnormal position described in Example 1, when the drilling and stealing abnormal position is 40m away from the wellhead, the current abnormal position can be accurately positioned, and the moving route can be accurately identified through coordinate changes, so as to carry out targeted control.

[0089] Embodiment 3

[0090] In a specific embodiment of the present application, the gas well to be monitored is located in a rectangular well field area in Sichuan.

[0091] Next, four points are constructed at the well site where the gas well to be monitored is located according to the four-point point arrangement method described in Example 1, and according to the propagation velocity measurement method described in Example 1, an open space with surface conditions consistent with those around the gas wellhead is selected around the well site, and two microseismic sensors are buried 30 cm below the surface, and the straight-line distance between the two microseismic sensors is 40 m. Afterwards, a building red brick is released at a height of 50 cm from the surface at point 1 to ensure that the maximum surface area of ​​the red brick vertically contacts the ground, and the time difference between the two sensors detecting the microseismic signal is recorded. The microseismic signal propagation velocity is the ratio of the difference in the distance between the two sensors and the brick-falling ground to the difference in the time of receiving the signal. Subsequently, the microseismic signal propagation velocity is measured at points 2 to 6 to obtain the measurement results shown in Table 6, and the average value of the 6 test results can be used as the propagation velocity under the surface conditions.

[0092] Table 6 Propagation velocity measurement results of Example 3

[0093]

[0094]

[0095] Next, according to the optimal monitoring distance calculation method described in Example 1, a microseismic sensor was buried 30 cm below the surface, and the microseismic sensors were stepped on the spot and dug with a hoe at 5 m, 10 m, 20 m, 30 m, 50 m, 80 m and 100 m away from the microseismic sensor, and the corresponding microseismic signals were collected. After testing, it was found that the optimal non-drilling theft monitoring distance of the microseismic sensor under such surface conditions was 30 m, and the optimal drilling theft monitoring distance was 50 m.

[0096] Further, according to Figure 5According to the point distribution method shown in FIG, four microseismic sensors are shallowly buried symmetrically at 45° at the wellhead of the gas well to be monitored. The distance between the microseismic sensors and the wellhead is 15 m, thereby forming the following four monitoring barriers around the gas well to be monitored, namely: 0-15 m, 15-30 m, 30-45 m and 45 m-65 m. The mapping relationship between the abnormal movement type and the abnormal movement occurrence area, as well as the mapping relationship between the point combination and the abnormal movement occurrence area, as shown in Tables 7 and 8, are obtained.

[0097] Table 7: Mapping relationship between abnormality type and abnormality occurrence area in Example 3

[0098] Length from wellhead / m Monitorable area Can monitor abnormal mode ＞65 / / 45～65 E. F Punch-hole stealing 30～45 C.D Punch-hole stealing, non-punch-hole stealing 15～30 B Punch-hole stealing, non-punch-hole stealing 0～15 A Punch-hole stealing, non-punch-hole stealing

[0099] Table 8: Mapping relationship between point combinations and abnormality occurrence areas in Example 3

[0100]

[0101] Finally, according to the precise positioning conditions and positioning methods of the abnormal position described in Example 1, when the non-drilling theft abnormal position is 20m away from the wellhead, the current abnormal position can be accurately positioned, and the moving route can be accurately identified through coordinate changes, so as to carry out targeted control.

[0102] Embodiment 4

[0103] In a specific embodiment of the present application, the gas well to be monitored is located in a rectangular well site area in the Ordos region. The Ordos region is located in a desert, and the surface is mainly dense sandy soil. The terrain in the Ordos region is flat, and it is often distributed in the desert with no shelter around it. Since there are clear boundaries and walls around the gas well site, there is almost no situation where vehicles rush in or large excavators drive in to cause damage. The types of abnormal movements such as vehicle driving and mechanical excavation can be ignored. In other words, there are only two types of abnormal movements in the gas well site: personnel approaching the gas well to steal natural gas through the sampling port at the wellhead (ie: non-drilling theft) and digging holes in the pipeline around the wellhead to steal natural gas (ie: drilling theft).

[0104] Next, four points are constructed in the well site where the gas well to be monitored is located according to the four-point point arrangement method described in Example 1, and according to the propagation velocity measurement method described in Example 1, an open space with surface conditions consistent with those around the gas wellhead is selected around the well site, and two microseismic sensors are buried 30 cm below the surface, and the straight-line distance between the two microseismic sensors is 40 m. Afterwards, a building red brick is released at a height of 50 cm from the surface at point 1 to ensure that the maximum surface area of ​​the red brick vertically contacts the ground, and the time difference between the two sensors detecting the microseismic signal is recorded. The microseismic signal propagation velocity is the ratio of the difference in the distance between the two sensors and the brick-falling ground to the difference in the time of receiving the signal. Subsequently, the microseismic signal propagation velocity is measured at points 2 to 6 to obtain the measurement results shown in Table 9. The average value of the 6 test results can be used as the propagation velocity under the surface conditions.

[0105] Table 9 Propagation velocity measurement results of Example 4

[0106] Measuring point Measuring speed 1 142.1 2 142.8 3 139.6 4 135.7 5 140.2 6 138.7 average value 139.9

[0107] Next, according to the optimal monitoring distance calculation method described in Example 1, a microseismic sensor is buried 30 cm below the surface, and steps are made and digs are made with a hoe at 5 m, 10 m, 15 m, 20 m, 25 m, 30 m, 35 m, 40 m, 50 m, 55 m, 60 m, 65 m, 70 m, 75 m and 80 m away from the microseismic sensor, and the corresponding microseismic signals are collected. After testing, it is found that the optimal non-drilling theft monitoring distance of the microseismic sensor under such surface conditions is 40 m, and the optimal drilling theft monitoring distance is 65 m.

[0108] Further, according to Figure 5 According to the point distribution method shown in FIG10 , four microseismic sensors are shallowly buried symmetrically at 45° at the wellhead of the gas well to be monitored. The distance between the microseismic sensors and the wellhead is 15 m, thereby forming the following four monitoring barriers around the gas well to be monitored, namely: 0-20 m, 20-40 m, 40-60 m and 60 m-85 m. The mapping relationship between the abnormal movement type and the abnormal movement occurrence area, as well as the mapping relationship between the point combination and the abnormal movement occurrence area, as shown in Tables 10 and 11, are obtained.

[0109] Table 10: Mapping relationship between abnormality type and abnormality occurrence area in Example 4

[0110] Length from wellhead / m Monitorable area Can monitor abnormal mode ＞85 / / 60～85 E. F Punch-hole stealing 40～60 C.D Punch-hole stealing, non-punch-hole stealing 20～40 B Punch-hole stealing, non-punch-hole stealing 0～20 A Punch-hole stealing, non-punch-hole stealing

[0111] Table 11: Mapping relationship between the four point combinations and the abnormality occurrence areas in the embodiment

[0112]

[0113] Finally, according to the precise positioning conditions and positioning methods of the abnormal position described in Example 1, when drilling to steal the abnormal position at a distance of 80m from the wellhead, the current abnormal position can be roughly positioned, but cannot be accurately positioned.

[0114] Embodiment 5

[0115] In a specific embodiment of the present application, the gas well to be monitored is located in a rectangular well field area in the Ordos region.

[0116] Next, four points are constructed in the well site where the gas well to be monitored is located according to the four-point point arrangement method described in Example 1, and according to the propagation velocity measurement method described in Example 1, an open space with surface conditions consistent with those around the gas wellhead is selected around the well site, and two microseismic sensors are buried 30 cm below the surface, and the straight-line distance between the two microseismic sensors is 40 m. Afterwards, a building red brick is released at a height of 50 cm from the surface at point 1 to ensure that the maximum surface area of ​​the red brick vertically contacts the ground, and the time difference between the two sensors detecting the microseismic signal is recorded. The microseismic signal propagation velocity is the ratio of the difference in the distance between the two sensors and the brick-falling ground to the difference in the time of receiving the signal. Subsequently, the microseismic signal propagation velocity is measured at points 2 to 6 to obtain the measurement results shown in Table 12, and the average value of the 6 test results can be used as the propagation velocity under the surface conditions.

[0117] Table 12 Propagation velocity measurement results of Example 5

[0118] Measuring point Measuring speed 1 142.1 2 142.8 3 139.6 4 135.7 5 140.2 6 138.7 average value 139.9

[0119] Next, according to the optimal monitoring distance calculation method described in Example 1, a microseismic sensor is buried 30 cm below the surface, and steps are made and digs are made with a hoe at 5 m, 10 m, 15 m, 20 m, 25 m, 30 m, 35 m, 40 m, 50 m, 55 m, 60 m, 65 m, 70 m, 75 m and 80 m away from the microseismic sensor, and the corresponding microseismic signals are collected. After testing, it is found that the optimal non-drilling theft monitoring distance of the microseismic sensor under such surface conditions is 40 m, and the optimal drilling theft monitoring distance is 65 m.

[0120] Further, according to Figure 5 According to the point distribution method shown in FIG14 , four microseismic sensors are shallowly buried symmetrically at 45° at the wellhead of the gas well to be monitored. The distance between the microseismic sensors and the wellhead is 20 m, thereby forming the following four monitoring barriers around the gas well to be monitored, namely: 0-20 m, 20-40 m, 40-60 m and 60 m-85 m. The mapping relationship between the abnormal movement type and the abnormal movement occurrence area, as well as the mapping relationship between the point combination and the abnormal movement occurrence area, as shown in Tables 13 and 14, are obtained.

[0121] Table 13: Mapping relationship between abnormality types and abnormality occurrence areas in Example 5

[0122] Length from wellhead / m Change occurred area Change Type ＞85 / / 60～85 E. F Punch-hole stealing 40～60 C.D Punch-hole stealing, non-punch-hole stealing 20～40 B Punch-hole stealing, non-punch-hole stealing 0～20 A Punch-hole stealing, non-punch-hole stealing

[0123] Table 14: Mapping relationship between point combinations and abnormality occurrence areas in Example 5

[0124]

[0125]

[0126] Finally, according to the precise positioning conditions and positioning methods of the abnormal position described in Example 1, when the non-drilling theft abnormal position is 50m away from the wellhead, the rough positioning of the current abnormal position can be achieved. When the abnormal position continues to approach the wellhead, if the moving direction is due east, due west, due south or due north, after moving 30m, it will enter area A from area C, and precise positioning can be achieved at this time; if the moving direction is southwest, northwest, southeast or northeast, it will enter area B, and precise positioning can also be achieved.

[0127] Embodiment 6

[0128] In a specific embodiment of the present application, the gas well to be monitored is located in the triangular well field area in Sichuan. The well field in this area is usually located on the top of a mountain, with no farmland around, which can basically exclude the damage to pipelines caused by reclamation. Therefore, after analysis, the most core type of abnormal movement is that people walk to the wellhead to steal gas (not drilling the hole).

[0129] Next, follow Figure 7 The three-point point arrangement method shown in the figure constructs three points at the well site where the gas well to be monitored is located, and according to the propagation velocity measurement method described in Example 1, selects an open space around the well site with surface conditions consistent with those around the gas wellhead, and buries two microseismic sensors 30 cm below the surface, respectively, and the straight-line distance between the two microseismic sensors is 40 m. Afterwards, a building red brick is released at a height of 50 cm from the surface at point 1 to ensure that the maximum surface area of ​​the red brick vertically contacts the ground, and the time difference between the two sensors detecting the microseismic signal is recorded. The microseismic signal propagation velocity is the ratio of the difference in the distance between the two sensors and the brick-falling ground to the difference in the time of receiving the signal. Subsequently, the microseismic signal propagation velocity is measured at points 2 to 6 to obtain the measurement results shown in Table 15, and the average value of the 6 test results can be used as the propagation velocity under the surface conditions.

[0130] Table 15 Propagation velocity measurement results of Example 6

[0131] Measuring point Measuring speed 1 131.3 2 132.9 3 128.4 4 119.6 5 130.6 6 129.8 average value 128.8

[0132] Next, according to the optimal monitoring distance calculation method described in Example 1, a microseismic sensor is buried 30 cm below the surface, and the corresponding microseismic signals are collected at 5 m, 10 m, 20 m, 30 m, 50 m, 80 m, and 100 m away from the microseismic sensor. After testing, the optimal non-drilling monitoring distance of the microseismic sensor under such surface conditions is 30 m.

[0133] Furthermore, according to the point distribution method described in Example 1, three microseismic sensors are shallowly buried around the wellhead of the gas well to be monitored, so that the three sensors form an equilateral triangle as vertices, and the distance between the microseismic sensors and the wellhead of the gas well is 15m, thereby forming three triangular-like monitoring barriers around the wellhead of the gas well to be monitored, and the mapping relationship between the point combination and the abnormal movement occurrence area as shown in Table 16 is obtained.

[0134] Table 16: Mapping relationship between point combinations and abnormality occurrence areas in Example 6

[0135] The sensor or point number in the point combination Abnormal occurrence area and positioning mode 1 Regional positioning: C1 2 Regional positioning: C2 3 Regional positioning: C3 1、2 Regional positioning: B2 2、3 Regional positioning: B3 1、3 Regional positioning: B1 1、2、3 Regional positioning: A; precise positioning

[0136] Finally, according to the precise positioning conditions and positioning methods of the abnormal position described in Example 1, when the non-drilling theft abnormality is 10m away from the wellhead, the personnel are in area A, and three sensors will monitor and warn at the same time. The following expression can be used to accurately locate the current abnormal position, and the moving route can be accurately judged by the coordinate change, so as to carry out targeted control:

[0137]

[0138]

[0139]

[0140] Where c represents the distance between sensors.

[0141] Embodiment 7

[0142] In a specific embodiment of the present application, the gas well to be monitored is located in the triangular well field area of ​​Ordos region. The well field in this area is usually located on the top of a mountain, with no farmland around, and pipeline damage caused by reclamation can be basically ruled out. Therefore, after analysis, drilling and theft are identified as the most core type of abnormality.

[0143] Next, three points are constructed at the well site where the gas well to be monitored is located according to the three-point point arrangement method described in Example 1, and according to the propagation velocity measurement method described in Example 1, an open space with surface conditions consistent with those around the gas wellhead is selected around the well site, and two microseismic sensors are buried 30 cm below the surface, and the straight-line distance between the two microseismic sensors is 40 m. Afterwards, a building red brick is released at a height of 50 cm from the surface at point 1 to ensure that the maximum surface area of ​​the red brick vertically contacts the ground, and the time difference between the two sensors detecting the microseismic signal is recorded. The microseismic signal propagation velocity is the ratio of the difference in the distance between the two sensors and the brick-falling ground to the difference in the time of receiving the signal. Subsequently, the microseismic signal propagation velocity is measured at points 2 to 6 to obtain the measurement results shown in Table 17, and the average value of the 6 test results can be used as the propagation velocity under the surface conditions.

[0144] Table 17 Propagation velocity measurement results of Example 7

[0145] Measuring point Measuring speed 1 142.1 2 142.8 3 139.6 4 135.7 5 140.2 6 138.7 average value 139.9

[0146] Next, according to the optimal monitoring distance calculation method described in Example 1, a microseismic sensor is buried 30 cm below the surface, and digging is performed with a hoe at 5 m, 10 m, 15 m, 20 m, 25 m, 30 m, 35 m, 40 m, 50 m, 55 m, 60 m, 65 m, 70 m, 75 m and 80 m from the microseismic sensor, and the corresponding microseismic signals are collected. After testing, it is found that the optimal drilling and stealing monitoring distance of the microseismic sensor under such surface conditions is 60 m.

[0147] Further, according to Figure 7 The point distribution method shown in FIG18 is to shallowly bury three microseismic sensors around the wellhead of the gas well to be monitored, so that the three sensors form an equilateral triangle as vertices. The distance between the microseismic sensors and the wellhead of the gas well is 30 m, thereby forming three triangular-shaped monitoring barriers around the wellhead of the gas well to be monitored, and obtain the mapping relationship between the point combination and the abnormal movement occurrence area as shown in Table 18.

[0148] Table 18: Mapping relationship between the seven point combinations and the abnormality occurrence areas in the embodiment

[0149] The sensor or point number in the point combination Abnormal occurrence area and positioning mode 1 Regional positioning: C1 2 Regional positioning: C2 3 Regional positioning: C3 1、2 Regional positioning: B2 2、3 Regional positioning: B3 1、3 Regional positioning: B1 1、2、3 Regional positioning: A; precise positioning

[0150] Finally, according to the precise positioning conditions and positioning methods of the abnormal position described in Example 1, when the non-drilling theft abnormal position is 50m away from the wellhead, the personnel are in area B or C, and the current abnormal position can be roughly positioned, but cannot be accurately positioned.

[0151] Embodiment 8

[0152] On the other hand, based on the external abnormal movement monitoring system for high-sulfur gas wells described in the above-mentioned embodiment 1, the embodiment of the present invention also proposes an external abnormal movement monitoring method for high-sulfur gas wells. The method utilizes the above-mentioned external abnormal movement monitoring system for high-sulfur gas wells to effectively realize the monitoring of external abnormal movements of high-sulfur gas wells. Figure 8 FIG. 1 is a step diagram of a method for monitoring external abnormalities of a high-sulfur gas well according to an embodiment of the present application. Figure 8 As shown, the external abnormal movement monitoring method for high-sulfur gas wells described in the present invention includes the following steps: Step S810 uses a signal receiving device 11 to construct multiple points in the well site where the gas well to be monitored is located, so that each point can receive the first microseismic signal in real time, wherein the first microseismic signal of each point is obtained by the second microseismic signal emitted by the target source after propagation in the well site; Step S820 extracts the signal characteristic parameters of the continuous microseismic signal of each point in step S810 in a specified time period through the abnormal movement type identification device 12, thereby determining the abnormal movement type; Step S830 The abnormal movement area identification device 13 determines one or more valid points and their position distribution that actually receive the second microseismic signal based on the first microseismic signals of multiple points in step S810, thereby determining the current abnormal movement area.

[0153] The present invention proposes a system and method for monitoring external abnormalities of high-sulfur gas wells. The signal receiving device of the system constructs multiple points at the well site where the gas well to be monitored is located, and collects microseismic signals related to abnormal activities (for example, intrusion by outsiders) at each point; the abnormality type identification device determines the abnormality type according to the characteristic parameters of the microseismic signal; the abnormality area identification device determines the current abnormality area according to the effective points and position distribution of the microseismic signals actually collected. The present invention proposes a reasonable and effective method for monitoring, early warning and locating external abnormalities of high-sulfur gas wells based on microseismic signals, which effectively expands the external abnormality monitoring range of high-sulfur gas wells, and can identify the abnormality type and locate the abnormality position. At the same time, the external abnormality monitoring system proposed by the present invention can also be promoted and applied in the field of safety monitoring of other key equipment and facilities such as oil and gas wells and oil and gas storage tanks, and has high economic value.

[0154] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any person familiar with the technology within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

[0155] It should be understood that the embodiments disclosed in the present invention are not limited to the specific structures, processing steps or materials disclosed herein, but should be extended to equivalent substitutions of these features understood by ordinary technicians in the relevant field. It should also be understood that the terms used herein are only used for the purpose of describing specific embodiments and are not meant to be limiting.

[0156] The "one embodiment" or "embodiment" mentioned in the specification means that the specific features, structures or characteristics described in conjunction with the embodiment are included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment" or "embodiment" appearing in various places throughout the specification do not necessarily refer to the same embodiment.

[0157] Although the embodiments disclosed in the present invention are as above, the contents described are only embodiments adopted for facilitating the understanding of the present invention and are not intended to limit the present invention. Any technician in the technical field to which the present invention belongs can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. An external abnormality monitoring system for high-sulfur gas wells, characterized in that: include: A signal receiving device is constructed at multiple points in the well site where the gas well to be monitored is located, each point is used to receive the first microseismic signal in real time, and the first microseismic signal at each point is obtained after the second microseismic signal emitted by the target source propagates in the well site; An abnormal movement type identification device is used to extract the signal characteristic parameters of the continuous microseismic signal of each point in a specified period of time, so as to determine the abnormal movement type; The abnormal movement area identification device is used to determine one or more effective points that actually receive the second microseismic signal and their position distribution according to the first microseismic signals of the multiple points, so as to determine the current abnormal movement area.

2. The external abnormality monitoring system according to claim 1, characterized in that: The multiple points are evenly distributed on a circle with the center of the gas well to be monitored as the center, wherein the position of each point is determined according to the optimal monitoring distance of each point.

3. The external abnormality monitoring system according to claim 2, characterized in that: The optimal monitoring distance includes: the optimal non-perforation theft monitoring distance and the optimal perforation theft monitoring distance, wherein: The optimal non-drilling theft monitoring distance / the optimal drilling theft monitoring distance are obtained by performing a walking test / an excavation test using a microseismic sensor arranged at any point in the well site.

4. The external abnormality monitoring system according to claim 2 or 3, characterized in that: The multiple points are at least three points, wherein: If the well field where the gas well to be monitored is located is a rectangular well field, a four-point point arrangement method is adopted; or If the well field where the gas well to be monitored is located is a triangular well field, a three-point point arrangement method is adopted.

5. The external abnormality monitoring system according to any one of claims 1 to 4, characterized in that: The signal receiving device comprises: A plurality of microseismic sensors are respectively arranged at different points, wherein the microseismic sensors are three-component microseismic sensors that meet specific technical parameter conditions, wherein the specific technical parameter conditions include but are not limited to: The bandwidth is 1~240Hz; GNSS timing accuracy is + / -10μs; Gain accuracy of 0.1%; and The sampling interval is less than or equal to 4ms.

6. The external abnormality monitoring system according to any one of claims 1 to 5, characterized in that: The abnormality type identification device comprises: A signal analysis unit, which is used to extract the receiving time and amplitude information from the continuous microseismic signal of each point as the signal characteristic parameters, so as to obtain the amplitude change characteristics and signal receiving time interval of each continuous microseismic signal; The abnormality type generating unit is used to determine the current abnormality type according to the amplitude change characteristics and the signal receiving time interval, wherein if the amplitude gradually increases, the current abnormality type is determined to be non-puncture theft, or if the amplitude remains unchanged and each signal receiving time interval is the same, the current abnormality type is determined to be punching theft.

7. The external abnormal movement monitoring system according to any one of claims 1 to 6, characterized in that: The abnormal area identification device comprises: An abnormality region division unit is used to plan multiple groups of point combinations with different numbers and positions of points capable of receiving the second microseismic signal, and match the abnormality occurrence area for each group of point combinations; The abnormal movement area generating unit is used to identify the number and positions of valid points that receive the second microseismic signal in real time according to the first microseismic signal of each point, determine the corresponding point combination and retrieve the abnormal movement area that matches the current point combination as the current abnormal movement area.

8. The external abnormal movement monitoring system according to any one of claims 1 to 7, characterized in that: The external abnormal movement monitoring system also includes: The abnormal movement tracking device is used to collect the determined abnormal movement area in real time, and determine the moving path of the abnormal movement area according to the generation time of the abnormal movement area, so as to track the abnormal movement situation.

9. The external abnormal movement monitoring system according to any one of claims 1 to 8, characterized in that: The abnormal area identification device is also used to calculate the coordinates of the current abnormal area using the center of the gas well to be monitored as the coordinate origin, using the distance between each effective point and the abnormal area, and the time difference between any two effective points receiving the microseismic signals, combined with the propagation distance of the second microseismic signal in the well field where the current gas well to be monitored is located, when the number of points that actually receive the second microseismic signal is greater than or equal to 3, so as to accurately locate the current abnormal area.

10. The external abnormality monitoring system according to claim 9, characterized in that: The abnormal area identification device comprises: A propagation velocity calculation unit is used to arrange microseismic sensors at any two points in the well site to receive the first microseismic signal of the experimental target source, and use the signal reception time difference between each microseismic sensor and the distance between the experimental target source and each microseismic sensor to calculate the propagation velocity of the microseismic signal in the well site where the gas well to be monitored is currently located, so as to obtain the propagation distance of the second microseismic signal in the well site where the gas well to be monitored is currently located.

11. The external abnormality monitoring system according to claim 9, characterized in that: The propagation velocity calculation unit is further used to calculate the difference in distance between the experimental target source and the microseismic sensors at any two points, and use the ratio between the distance difference and the signal reception time difference as the propagation velocity.

12. A method for monitoring external abnormalities in high-sulfur gas wells, characterized in that: The external abnormality monitoring method is implemented by using the external abnormality monitoring system according to any one of claims 1 to 11, and the external abnormality monitoring method comprises: A signal receiving device is used to construct multiple points at the well site where the gas well to be monitored is located, so that each point can receive the first microseismic signal in real time, wherein the first microseismic signal at each point is obtained after the second microseismic signal emitted by the target source propagates in the well site; The signal characteristic parameters of the continuous microseismic signal of each point in a specified period of time are extracted by the abnormal movement type identification device, so as to determine the abnormal movement type; The abnormal movement area identification device determines one or more valid points that actually receive the second microseismic signal and their position distribution according to the first microseismic signals of the multiple points, thereby determining the current abnormal movement area.

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