Gas control system for hydraulic punching of soft coal seam

Abstract

The utility model relates to a gas control system for hydraulic punching of a soft coal seam, and belongs to the technical field of gas extraction. Comprising a plurality of drill holes distributed in the soft coal seam side by side, a hydraulic punching cavity formed after hydraulic punching is formed in each drill hole, and a telescopic supporting device is arranged at each hydraulic punching cavity; an extraction branch pipeline is arranged at an opening in the outer side of each drill hole, and a pressure regulating valve and a sensor assembly are arranged on each extraction branch pipeline; one end, far away from the drill hole, of each extraction branch pipeline is connected with the extraction main pipeline; the problems of invalid dredging and gas accumulation caused by the fact that true collapse holes and false collapse holes cannot be distinguished at present are solved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of gas extraction, and particularly relates to a gas treatment system for soft coal seam hydraulic punching. BACKGROUND

[0002] The soft coal seam becomes a key area for gas extraction due to its low strength and high permeability, and the hydraulic punching technology significantly improves the gas desorption efficiency through high-pressure water jet reaming. However, the oversized aperture formed by reaming will damage the mechanical balance of the hole wall, thereby inducing a hole collapse accident. The collapsed coal not only blocks the local extraction channel, but also has strong concealment and is difficult to identify. After the hole collapse occurs, the traditional monitoring relies on a single-hole flow threshold alarm and cannot distinguish between true hole collapse (gas channel complete blockage) and false hole collapse (gas transferred to the adjacent hole through the crack), resulting in invalid dredging operation on the false hole collapse with no gas quantity decay, causing resource waste. More seriously, the abnormal migration of gas caused by hole collapse will disturb the pipe network pressure distribution and induce local gas accumulation risk. The traditional supporting means (such as casing) cannot be applied due to hindering the water jet operation, and there is an urgent need for a cavity supporting device that can be deployed synchronously with reaming without interfering with the punching process, and a system that can real-time distinguish the hole collapse type, accurately locate the true hole collapse and intelligently control, to ensure the safety and efficiency of extraction. SUMMARY

[0003] The utility model overcomes the defects of the prior art and provides a gas treatment system for soft coal seam hydraulic punching, which solves the problem of invalid dredging and gas accumulation caused by the inability to distinguish between true hole collapse and false hole collapse.

[0004] To achieve the above purpose, the utility model is implemented by the following technical solutions.

[0005] A gas treatment system for soft coal seam hydraulic punching includes a plurality of drill holes distributed side by side on the soft coal seam, each drill hole is provided with a hydraulic punching cavity formed after hydraulic punching, and each hydraulic punching cavity is provided with an extendable supporting device; each drill hole is provided with an extraction branch pipe at the outer opening, each extraction branch pipe is provided with a pressure regulating valve and a sensor assembly; and the ends of all extraction branch pipes away from the drill holes are connected with an extraction main pipe.

[0006] Further, the supporting device comprises a sliding rod, a sliding seat, a fixed support disc, a sliding support disc, a support arm, and an electric telescopic rod; the fixed support disc is fixedly arranged at one end of the sliding rod, the sliding support disc is slidably arranged at the other end of the sliding rod, three groups of support arms are arranged between the fixed support disc and the sliding support disc, the support arms are formed by three support rods hingedly connected at the ends, and the ends of the two support rods on the two sides are hingedly connected with the fixed support disc and the sliding support disc respectively; the sliding seat is slidably arranged at the outer side of the middle part of the sliding rod, three electric telescopic rods are fixedly arranged on the outer side of the sliding seat, the three electric telescopic rods correspond to the three groups of support arms respectively, the cylinder body end of the electric telescopic rod is fixedly connected with the outer side of the sliding seat, and the piston rod end of the electric telescopic rod is hingedly connected with the middle part of the support rod of the corresponding support arm.

[0007] Further, the three groups of support arms are circularly arranged around the axis of the sliding rod.

[0008] Further, the lengths of the two support rods on the two sides are equal, and the length direction of the support rod of the middle part is parallel to the axis of the sliding rod.

[0009] Further, the three electric telescopic rods are circularly arranged around the axis of the sliding rod, and the axes of the three electric telescopic rods are perpendicular to the axis of the sliding rod.

[0010] Further, the sensor assembly is located on the side of the pressure regulating valve close to the extraction main pipeline.

[0011] Further, the sensor assembly comprises a sensor probe, a flow rate sensor, a pressure sensor, and a gas concentration sensor.

[0012] The beneficial effects of the utility model relative to the prior art are as follows:

[0013] 1. The supporting device has a small outer diameter in the contracted state, can be placed in the drill hole in advance before hydraulic punching, or quickly extended after the punching is completed, and interference with the high-pressure water jet is avoided.

[0014] 2. After the hole expansion is completed, the supporting device is quickly unfolded by controlling the electric telescopic rod, the support arm is attached to the hole wall, the mechanical balance of the hole wall is maintained from the physical structure, the hole collapse is blocked, the unfolding stroke of the support arm can be controlled by the electric telescopic rod, and the supporting device is suitable for hydraulic punching cavities of different sizes; the sliding rod is guided and uniformly distributed by the multiple groups of support arms, the supporting force is balanced, and the secondary damage to the hole wall caused by local stress concentration is avoided.

[0015] 3.The traditional monitoring means only relies on single-hole flow threshold alarm, and cannot distinguish between true hole collapse and false hole collapse, and often performs dredging operation on false hole collapse with undecayed gas content, causing waste of manpower, material resources and time. The utility model can accurately judge the gas channel blockage (true hole collapse) and gas migration (false hole collapse) according to the gas content response amplitude of adjacent holes by real-time monitoring of the gas content (concentration x flow) of each extraction hole, combining with the pipe network pressure difference disturbance test, and only starting dredging for true hole collapse and high blockage grade holes, effectively avoiding invalid operation and improving operation efficiency.

[0016] 4.The existing technology such as borehole viewer needs to stop for detection, and has the problem of response lag; the stress sensor network is too high in cost and is disconnected from the gas flow state, and it is difficult to grasp the gas dynamic change caused by hole collapse in real time. The utility model can quickly capture the abnormal migration of gas caused by hole collapse and the change of pipe network pressure distribution by real-time monitoring of gas concentration, flow, flow rate, pressure and other parameters through the sensor system, and maintain the balance of pipe network pressure through closed-loop control adjustment of pressure regulating valve, timely prevent local gas overrun, and greatly improve the safety of extraction operation. BRIEF DESCRIPTION OF DRAWINGS

[0017] The utility model will be further described in detail in combination with the drawings:

[0018] Figure 1 is the structural schematic view of the supporting device in the hole in the contracted state;

[0019] Figure 2 is the structural schematic view of the supporting device in the hole in the supporting state;

[0020] Figure 3 is the structural schematic view of the hole in the false hole collapse;

[0021] Figure 4 is the structural schematic view of the hole in the true hole collapse;

[0022] Figure 5 is the structural schematic view of the supporting device in the supporting state;

[0023] Figure 6 is the structural schematic view of the supporting device in the contracted state;

[0024] Figure 7 is the structural schematic view of the sensor assembly;

[0025] Wherein, 1 is soft coal seam, 2 is drill hole, 3 is hydraulic flushing cavity, 4 is supporting device, 5 is extraction branch pipeline, 6 is pressure regulating valve, 7 is sensor assembly, 8 is extraction main pipeline, 9 is sliding rod, 10 is fixed support disc, 11 is sliding support disc, 12 is support arm, 13 is sliding seat, 14 is electric telescopic rod, 15 is sensor probe, 16 is flow rate sensor, 17 is pressure sensor, 18 is gas concentration sensor, 19 is true hole collapse, 20 is false hole collapse. DETAILED DESCRIPTION

[0026] In order to make the technical problems, technical schemes and beneficial effects to be solved by the utility model more clear and obvious, the utility model is further described in detail in combination with embodiments and drawings. It should be understood that the specific embodiments described herein are only used to explain the utility model, and are not used to limit the utility model. The technical scheme of the utility model is described in detail below in combination with embodiments and drawings, but the protection scope is not limited by this.

[0027] As shown in Figure 1 The utility model provides a kind of gas control system for soft coal seam hydraulic flushing, as shown in Fig. 7, it includes and is distributed in the multiple drill holes 2 of soft coal seam 1 side by side, each drill hole 2 inside is provided with the hydraulic flushing cavity 3 formed after hydraulic flushing, and each hydraulic flushing cavity 3 is provided with telescopic supporting device 4;The outside opening of each drill hole 2 is provided with one extraction branch pipeline 5, and each extraction branch pipeline 5 is provided with one pressure regulating valve 6 and one sensor assembly 7;The end of all extraction branch pipelines 5 away from drill hole 2 is connected with extraction main pipeline 8.

[0028] The supporting device 4 includes sliding rod 9, sliding seat 13, fixed support disc 10, sliding support disc 11, support arm 12, electric telescopic rod 14.

[0029] A fixed support disc 10 is fixedly arranged at one end of the slide rod 9, a sliding support disc 11 is slidingly arranged at the other end of the slide rod 9, three groups of support arms 12 are arranged between the fixed support disc 10 and the sliding support disc 11, and the three groups of support arms 12 are circularly arranged around the axis of the slide rod 9. The support arm 12 is formed by hingedly connecting three support rods, the two support rods on the sides are equal in length, and the length direction of the support rod in the middle is parallel to the axis of the slide rod 9. The two support rods on the sides are hingedly connected to the fixed support disc 10 and the sliding support disc 11 respectively at the ends away from each other. A sliding seat 13 is slidingly arranged at the middle of the slide rod 9, three electric telescopic rods 14 are fixedly arranged on the outer side of the sliding seat 13, the three electric telescopic rods 14 are circularly arranged around the axis of the slide rod 9, and the axes of the three electric telescopic rods 14 are perpendicular to the axis of the slide rod 9. The three electric telescopic rods 14 correspond to the three groups of support arms 12 respectively, one end of the cylinder body of the electric telescopic rod 14 is fixedly connected to the outer side of the sliding seat 13, and one end of the piston rod of the electric telescopic rod 14 is hingedly connected to the middle section of the support rod in the corresponding support arm 12.

[0030] When the piston rods of the three electric telescopic rods 14 are controlled to be synchronously retracted, the support rods in the middle of the three groups of support arms 12 simultaneously approach the slide rod 9, the angle between the support rod in the middle and the support rods on the two sides gradually increases, the distance between the fixed support disc 10 and the sliding support disc 11 gradually increases, and the support device 4 changes into the retracted state.

[0031] When the piston rods of the three electric telescopic rods 14 are controlled to be synchronously extended, the support rods in the middle of the three groups of support arms 12 simultaneously move away from the slide rod 9, the angle between the support rod in the middle and the support rods on the two sides gradually decreases, the distance between the fixed support disc 10 and the sliding support disc 11 gradually decreases, and the support device 4 changes into the supporting state.

[0032] The sensor assembly 7 is located on the side of the pressure regulating valve 6 close to the extraction main pipeline 8. The extraction pressure of each extraction branch pipeline 5 can be controlled by adjusting the opening degree of the pressure regulating valve 6.

[0033] The sensor assembly 7 comprises a sensor probe 15, a flow rate sensor 16, a pressure sensor 17 and a gas concentration sensor 18. The sensor probe 15 is directly in contact with the gas medium in the extraction branch pipeline 5, and converts the monitored physical quantity into an electrical signal and transmits the electrical signal to a data processing system. The flow rate sensor 16 is used for monitoring the flow speed of the gas in the extraction branch pipeline 5 in real time, the pressure sensor 17 is responsible for collecting the pressure data in the extraction branch pipeline 5, and the gas concentration sensor 18 accurately detects the gas concentration in the extraction branch pipeline 5.

[0034] The working principle of the utility model is:

[0035] Three parallel drill holes 2 are drilled in the soft coal seam 1, and hydraulic flushing is performed in each drill hole 2 to form a segmented hydraulic flushing cavity 3 in each drill hole 2. The supporting device 4 in the contracted state is extended along the drill hole 2 to the hydraulic flushing cavity 3, and then the three electric telescopic rods 14 of the supporting device 4 are synchronously extended to drive the supporting device 4 to the supporting state, thereby supporting the inner wall of the hydraulic flushing cavity 3.

[0036] When it is necessary to determine whether the drill hole 2 in the soft coal seam 1 collapses after hydraulic flushing, the gas concentration sensor 18 and the flow rate sensor 16 on the drainage branch pipeline 5 outside the drill hole 2 are used for judgment. According to the pipe diameter of the drainage branch pipeline 5, the gas flow rate can be obtained, and then the gas quantity W i =C i ×Q i (C i is the concentration, and Q i is the flow rate). When the flow rate in the drainage branch pipeline 5 is significantly reduced, but the gas purity basically remains unchanged, it is determined that there is a false collapse 20, and it is recorded that no dredging is needed. When the flow rate in the drainage branch pipeline 5 is significantly reduced, and the gas purity is also significantly decreased, it is determined that there is a true collapse 19, and it is recorded that dredging is needed.

[0037] When the drill hole 2 needs to be dredged, the opening of the pressure regulating valve 6 on the drainage branch pipeline 5 corresponding to the drill hole 2 that needs to be dredged is adjusted to increase the negative pressure of the drainage branch pipeline 5 that needs to be dredged, and then the flow rate sensors 16 corresponding to the drill holes 2 on both sides of the drill hole 2 that needs to be dredged are observed. If the gas flows into the drainage branch pipeline 5 on both sides, it means that the drainage branch pipeline 5 corresponding to the drill hole 2 that needs to be dredged is not blocked, and the pressure difference causes the gas in the drainage branch pipeline 5 on both sides to flow in the opposite direction. According to the calculated flow rate and pressure theoretical change value of the drainage branch pipeline 5 on both sides after pressure regulation, the actual change value of the flow rate and pressure of the drainage branch pipeline 5 on both sides is observed. If the actual change value of the flow rate and pressure is close to the theoretical change value, it means that the drill hole 2 that needs to be dredged is not blocked seriously, and the conventional dredging process is used for treatment. If the actual change value of the flow rate and pressure is significantly different from the theoretical change value, it means that the drill hole 2 that needs to be dredged is blocked seriously, and needs to be treated by enhanced dredging.

[0038] When the supporting device 4 needs to be taken out of the drill hole 2, the three electric telescopic rods 14 of the supporting device 4 are synchronously retracted to drive the supporting device 4 to the contracted state, so that the supporting device 4 can be smoothly taken out of the drill hole 2.

[0039] It is apparent for a person skilled in the art that the present application is not restricted to the details of the above exemplary embodiments, but that it can be implemented in other concrete forms without departing from the spirit or the essential characteristics of the present application. Therefore, the embodiments should be considered as exemplary only, and not limiting, the scope of the present application being defined by the appended claims rather than by the above description, and all changes coming within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference signs in the claims should not be construed as limiting the claims concerned.

Claims

1. A gas control system for hydraulic punching of soft coal seams, characterized in that: It includes multiple drill holes (2) distributed side by side on the soft coal seam (1), each drill hole (2) is internally provided with a hydraulic flushing cavity (3) formed after hydraulic flushing, and each hydraulic flushing cavity (3) is provided with a telescopic supporting device (4); the outer opening of each drill hole (2) is provided with an extraction branch pipeline (5), each extraction branch pipeline (5) is provided with a pressure regulating valve (6) and a sensor assembly (7); and the ends of all extraction branch pipelines (5) away from the drill holes (2) are connected with an extraction main pipeline (8).

2. A gas control system for hydraulic punching in soft coal seams according to claim 1, characterized in that: The supporting device (4) comprises a sliding rod (9), a sliding seat (13), a fixed support disc (10), a sliding support disc (11), a support arm (12), and an electric telescopic rod (14); the fixed support disc (10) is fixedly arranged at one end of the sliding rod (9), the sliding support disc (11) is slidably arranged at the other end of the sliding rod (9), three groups of support arms (12) are arranged between the fixed support disc (10) and the sliding support disc (11), the support arm (12) is formed by three support rods hingedly connected at the ends, the ends of the two support rods away from each other are hingedly connected with the fixed support disc (10) and the sliding support disc (11) respectively; the sliding seat (13) is slidably arranged at the middle of the sliding rod (9), three electric telescopic rods (14) are fixedly arranged on the outer side of the sliding seat (13), the three electric telescopic rods (14) correspond to the three groups of support arms (12) respectively, the cylinder end of the electric telescopic rod (14) is fixedly connected with the outer side of the sliding seat (13), and the piston rod end of the electric telescopic rod (14) is hingedly connected with the middle section of the support rod of the corresponding support arm (12).

3. A gas control system for hydraulic flushing of soft coal seams according to claim 2, characterized in that: The three groups of support arms (12) are circularly arranged around the axis of the sliding rod (9).

4. The gas control system for hydraulic flushing of soft coal seams according to claim 2, characterized in that: The lengths of the two support rods on the two sides are equal, and the length direction of the middle support rod is parallel to the axis of the sliding rod (9).

5. The gas control system for hydraulic flushing of soft coal seams according to claim 2, characterized in that: The three electric telescopic rods (14) are circularly arranged around the axis of the sliding rod (9), and the axes of the three electric telescopic rods (14) are perpendicular to the axis of the sliding rod (9).

6. A gas control system for hydraulic flushing of soft coal seams according to claim 1, characterized in that: The sensor assembly (7) is located on the side of the pressure regulating valve (6) close to the extraction main pipeline (8).

7. A gas control system for hydraulic flushing of soft coal seams according to claim 1, characterized in that: The sensor assembly (7) comprises a sensor probe (15), a flow rate sensor (16), a pressure sensor (17), and a gas concentration sensor (18).

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