Coal mine staged hydraulic fracturing measurement-while-pressure equipment and method

Abstract

The invention belongs to the technical field of coal mine hydraulic fracturing, and particularly relates to coal mine staged hydraulic fracturing measurement-while-pressure equipment and a coal mine staged hydraulic fracturing measurement-while-pressure method. The equipment comprises the resistivity imager and the segmented hydraulic fracturing equipment, the resistivity imager comprises a measuring electrode, a processor, a signal processing module and a display and control system, and the measuring electrode and the processor are installed on the segmented hydraulic fracturing equipment and connected with the display and control system through cables or wireless signals. The signal processing module is installed in the display and control system. The segmented hydraulic fracturing equipment performs fracturing detection through the resistivity imager during construction and transmits signals to the display and control system. According to the method, a high-resolution resistivity imager and segmented hydraulic fracturing equipment are adopted, a to-be-fractured part is fractured through segmented hydraulic fracturing, meanwhile, the fractured part of the previous segment is monitored, and the technical method of fracturing and monitoring at the same time is formed. The method is simple and easy to implement.

Description

Technical Field

[0001] The invention belongs to the technical field of hydraulic fracturing in coal mines, and in particular relates to equipment and method for measuring pressure and measuring at the same time for staged hydraulic fracturing in coal mines. Background Art

[0002] With the increase in demand for coal, coal mining is becoming deeper and deeper. Due to the complex stress and geological structure of deep horizontal mining, the threats of disasters such as rock burst, roof, and dust are becoming more and more serious. Hydraulic fracturing technology can effectively break the coal or rock mass, increase the original pore cracks, and produce a complex fracture network, increase the water content of the coal body, and thus effectively prevent disasters such as rock burst, roof, and dust. In recent years, with the development of science and technology and the improvement of equipment, segmented hydraulic fracturing technology has been formed to effectively control the distance of a single fracturing and improve the fracturing effect. However, the monitoring of the effect of segmented hydraulic fracturing has always troubled scientific researchers and construction personnel, and the effect of hydraulic fracturing construction cannot be effectively evaluated. Therefore, it is necessary to propose an equipment and method that can perform segmented fracturing and monitor the effect at any time. During the segmented hydraulic fracturing construction process, it can monitor while fracturing, and provide equipment and methods for evaluating the effect of segmented hydraulic fracturing construction. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a coal mine segmented hydraulic fracturing and monitoring equipment and method, which uses a high-resolution resistivity imager and a segmented hydraulic fracturing component to measure the coal mine boreholes while they are being pressurized, forming a technical method of monitoring while fracturing, so as to grasp the fracturing effect at any time.

[0004] The technical solutions adopted are:

[0005] A coal mine segmented hydraulic fracturing and pressure-along-measurement equipment comprises a resistivity imager and segmented hydraulic fracturing equipment, wherein the resistivity imager comprises measuring electrodes, a processor, a signal processing module, and a display and control system; the measuring electrodes and the processor are mounted on the segmented hydraulic fracturing equipment and connected to the display and control system via cables or wireless signals, and the signal processing module is mounted inside the display and control system; during construction, the segmented hydraulic fracturing equipment performs fracturing detection via the resistivity imager and transmits the signal to the display and control system.

[0006] Preferably, the staged hydraulic fracturing equipment includes a fracturing assembly, a high-pressure hose, a pump group, and a water tank; the fracturing assembly includes a guide bend, a check valve, a packer, a throttle, a packer, a safety release, and a fracturing string in sequence; the measuring electrodes and the processor are installed in sequence between the guide bend and the check valve.

[0007] Preferably, the fracturing string is connected to a high-pressure hose via a union joint.

[0008] Preferably, the high-pressure hose is connected to a three-way valve, one end of the three-way valve is connected to the pump group and the water tank, and the other end is connected to the high-pressure gate valve; wherein the pump group and the water tank are connected via a bellows.

[0009] An application method of a pressure-along-measurement equipment for staged hydraulic fracturing in coal mines comprises the following steps:

[0010] (1) Install the measuring electrodes and processor of the resistivity imager at the rear end of the guide inclination of the fracturing assembly in sequence, and then connect the processor to the check valve, packer, throttle, packer, safety release and fracturing string in sequence. The fracturing string is connected to the high-pressure hose through a union joint, and then connected to the three-way valve, pump group and water tank in sequence. The other end of the three-way valve is connected to the high-pressure gate valve, and the measuring electrodes and processor are connected to the display and control system; push the connected fracturing assembly to the bottom of the borehole;

[0011] (2) starting the pump group to perform fracturing on the first fracturing area of ​​the borehole, and after the fracturing is completed, closing the pump group, withdrawing the rod for a certain distance, and moving the measuring electrode of the resistivity imaging instrument to the location of the first fracturing area;

[0012] (3) Turn on the power supply and pump group of the resistivity imager at the same time, monitor the coal body at the location of the first stage fracturing area, judge the fracturing effect, and fractur e the second stage fracturing area at the same time; after the fracturing is completed, turn off the pump group, and withdraw the rod for a certain distance to move the resistivity imager to the location of the second stage fracturing area;

[0013] (4) Repeat the above step (3) until all the holes are fractured.

[0014] Preferably, the resistivity imager is a high-resolution resistivity imager based on microresistivity imaging technology, and injects survey current through capacitive coupling between the electrode array and the formation.

[0015] Preferably, the survey current propagates in the formation and is detected by the measuring electrode. The processor analyzes the current and calculates the resistivity of the formation. The signal processing module processes the resistivity and presents the fracture conditions of the coal body in the monitoring area on the display and control system.

[0016] Preferably, the pump group is any one of a high-pressure pump group and a variable flow pump group.

[0017] Preferably, the high-pressure pump group includes a high-pressure pump and an explosion-proof variable frequency motor, and the explosion-proof variable frequency motor is connected to the high-pressure pump, and the transmission of the explosion-proof variable frequency motor drives the piston in the high-pressure pump to move, thereby forming high-pressure water.

[0018] Preferably, at least two water injection units are connected in series in the variable rheological pump group, and each water injection unit includes a power end and a hydraulic end; the power end of a water injection unit in the pump group is connected through a driving shaft, and then connected through a clutch, and the other end of the clutch is connected to the power end of other water injection units through a driven shaft, and the clutch can be automatically closed and opened.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention uses a high-resolution resistivity imager and a staged hydraulic fracturing device, and can monitor the fracturing effect while fracturing during the on-site construction of staged hydraulic fracturing, effectively solving the technical problem in the prior art that the staged hydraulic fracturing effect cannot be monitored or can only be indirectly evaluated by monitoring means such as peepholes and microseismic monitoring.

[0021] The present invention combines resistivity imaging technology with staged hydraulic fracturing technology. While the staged hydraulic fracturing is fracturing the part to be fractured, the previous fracturing part is monitored, thus forming a technical method of monitoring while fracturing.

[0022] A three-way valve is used, and the other end is connected to a high-pressure gate valve, so that the high-pressure gate valve can be opened after the pump is stopped to quickly relieve the water pressure in the fracturing assembly. The high-pressure hose and the fracturing string are connected through a union joint, which is convenient and leak-proof.

[0023] The segmented hydraulic fracturing equipment of the present invention is connected with a safety release. When a hole collapse occurs, the fracturing equipment cannot be completely withdrawn from the borehole. At this time, the ball hits the safety release, causing the T-shaped buckle in the middle of the safety release to break, thereby withdrawing all components connected to the rear of the safety release from the borehole, reducing the loss of equipment cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention is a schematic structural diagram of a coal mine segmented hydraulic fracturing and pressure-along-measurement equipment.

[0025] Figure 2 This is a schematic diagram of the internal structure of the pump group in Example 1 of the present invention.

[0026] In the figure, 1-measuring electrode, 2-processor, 3-signal processing module, 4-display and control system, 5-cable, 6-inclination, 7-check valve, 8-packer, 9-throttle, 10-fracturing string, 11-safety release, 12-high-pressure hose, 13-pump group, 14-water tank, 15-union joint, 16-three-way valve, 17-high-pressure gate valve, 18-bellows, 19-clutch, 20-water injection unit, 21-driving shaft, 22-power end, 23-hydraulic end, 24-export. DETAILED DESCRIPTION

[0027] The accompanying drawings are only used for illustrative purposes and are only for the convenience of describing the present invention and simplifying the description, and should not be understood as limiting the present invention. In order to make the purpose, technical solution and beneficial effects of the present invention more clear, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. The places not mentioned are the same as the common practices in the prior art. If there is no special description, some electrical components used in the present invention can be purchased through conventional channels.

[0028] Example 1

[0029] like Figure 1 As shown, a coal mine segmented hydraulic fracturing pressure-along-measurement equipment includes a resistivity imager and a segmented hydraulic fracturing device. The resistivity imager includes a measuring electrode 1, a processor 2, a signal processing module 3, and a display and control system 4. The measuring electrode 1 and the processor 2 are installed on the segmented hydraulic fracturing device, and are connected to the display and control system 4 through a cable 5 or a wireless signal. The signal processing module 3 is installed inside the display and control system 4. During construction, the segmented hydraulic fracturing device performs fracturing detection through the resistivity imager and transmits the signal to the display and control system 4.

[0030] The staged hydraulic fracturing equipment includes a fracturing assembly, a high-pressure hose 12, a pump group 13, and a water tank 14; the fracturing assembly includes a deflector 6, a check valve 7, a packer 8, a throttle 9, a packer, a safety release 11, and a fracturing string 10 in sequence; the measuring electrode 1 and the processor 2 are installed in sequence between the deflector 6 and the check valve 7. The fracturing string 10 is connected to the high-pressure hose 12 through a union 15. The high-pressure hose 12 is connected to a three-way valve 16, one end of the three-way valve 16 is connected to the pump group 13 and the water tank 14, and the other end is connected to a high-pressure gate valve 17. Among them, the pump group 13 and the water tank 14 are connected through a bellows 18.

[0031] The resistivity imager used in the present invention is a high-resolution resistivity imager, which is based on microresistivity imaging technology and injects survey current through capacitive coupling between the electrode array and the formation. These currents propagate in the formation and are detected by the measuring electrode 1. The processor 2 analyzes the current and then calculates the resistivity of the formation. The signal processing module 3 processes the resistivity and presents the cracks of the coal body in the monitoring area on the display and control system 4.

[0032] like Figure 2As shown, the pump group 13 is a variable flow pump group, and the variable flow pump group includes a pump body and a flow meter; the pump body includes a power end 22, a hydraulic end 23, and a clutch 19, and the power end 22 and the hydraulic end 23 constitute a water injection unit 20. Two (three or four water injection units can also be connected in series as needed) water injection units 20 are connected in series in the variable rheological pump group. The power end 22 of a water injection unit 20 in the pump group is connected by a driving shaft 21, and then connected by a clutch 19. The other end of the clutch 19 is connected to the power end of other water injection units 20 through a driven shaft, and the clutch 19 can realize automatic closing and disconnection. The output flow rate of each water injection unit 20 is 2.0m 3 / min, the flow rate of two groups of water injection units 20 in series is 4.0m 3 The fixed frequency motor (Lulue) is connected to the driving shaft 21 to drive the driving shaft 21 to rotate at a high speed, and the driving shaft 21 drives the variable flow pump group to work. The outlet 24 of the pump group 13 is connected to the three-way valve 16 through a high-pressure hose.

[0033] The present invention adopts an application method of a coal mine segmented hydraulic fracturing and pressure-monitoring equipment, comprising the following steps:

[0034] (1) The measuring electrode 1 and the processor 2 of the resistivity imager are sequentially installed at the rear end of the guide bevel 6 of the fracturing assembly, wherein the measuring electrode 1 has 8 plates, each of which is equipped with an array of 24 button electrodes, and then the processor is sequentially connected to the check valve 7, the packer 8, the throttle 9, the packer, the safety release 11 and the fracturing string 10, the fracturing string 10 is connected to the high-pressure hose 12 through the union 15, and then sequentially connected to the three-way valve 16, the pump group 13, and the water tank 14, the other end of the three-way valve 16 is connected to the high-pressure gate valve 17, and the measuring electrode 1 and the processor 2 are connected to the display and control system 4; the connected fracturing assembly is pushed to the bottom of the borehole;

[0035] (2) starting the pump group 13 to perform fracturing on the first fracturing area of ​​the borehole, and closing the pump group 13 after the fracturing is completed, and withdrawing the rod for a certain distance so that the measuring electrode 1 of the resistivity imager moves to the location of the first fracturing area;

[0036] (3) Turn on the power supply of the resistivity imager and the pump group 13 at the same time, monitor the coal body at the location of the first stage fracturing area, judge the fracturing effect, and fractur e the second stage fracturing area at the same time; after the fracturing is completed, turn off the pump group, and withdraw the rod for a certain distance to move the resistivity imager to the location of the second stage fracturing area;

[0037] (4) Repeat the above step (3) until all the holes are fractured.

[0038] The clutch 19 is a dry single-disc electromagnetic clutch. The clutch is in a closed state, the driving shaft 21 and the driven shaft are in a connected state, and the two groups of water injection units 20 are connected in series for operation. There is no slippage during operation and no wear after connection. The water injection flow rate of the pump group is increased by connecting the two groups of water injection units 20 in series. The flow rate of the water outlet of the pump body is monitored by a flow meter.

[0039] The variable flow pump set of the present invention can also realize the conversion of different water injection flow rates according to needs, for example, it can realize 2.0m 3 / min, 6.0m 3 / min water injection flow rate, etc.

[0040] Example 2

[0041] A pressure-fracturing and monitoring equipment for coal mine segmented hydraulic fracturing. The pump group is a high-pressure pump group. The high-pressure pump group includes a high-pressure pump and an explosion-proof variable frequency motor. The explosion-proof variable frequency motor is connected to the high-pressure pump, and the transmission of the explosion-proof variable frequency motor drives the piston in the high-pressure pump to move, thereby forming high-pressure water. The high-pressure pump group is connected to the water tank through a bellows.

[0042] The display and control system 4 is installed with the software of the frequency conversion control device, and the display and control system 4 is connected to the explosion-proof frequency conversion motor, controls the explosion-proof frequency conversion motor, and displays the real-time monitored water outlet pressure and flow. The display and control system can change the output power of the explosion-proof frequency conversion motor, thereby realizing the frequency conversion of the water outlet pressure and flow of the high-pressure plunger pump.

[0043] The present invention adopts an application method of a coal mine segmented hydraulic fracturing and pressure-monitoring equipment, comprising the following steps:

[0044] (1) The measuring electrode 1 and the processor 2 of the resistivity imager are sequentially installed at the rear end of the guide bevel 6 of the fracturing assembly, wherein the measuring electrode 1 has 8 plates, each of which is equipped with an array of 24 button electrodes, and then the processor 2 is sequentially connected to the check valve 7, the packer 8, the throttle 9, the packer, the safety release 11 and the fracturing string 10, the fracturing string 10 is connected to the high-pressure hose 12 through the union 15, and then sequentially connected to the three-way valve 16, the pump group 13, and the water tank 14, the other end of the three-way valve 16 is connected to the high-pressure gate valve 17, and the measuring electrode 1 and the processor 2 are connected to the display and control system 4; the connected fracturing assembly is pushed to the bottom of the borehole;

[0045] (2) starting the pump group 13 to perform fracturing on the first fracturing area of ​​the borehole, and closing the pump group 13 after the fracturing is completed, and withdrawing the rod for a certain distance so that the measuring electrode 1 of the resistivity imager moves to the location of the first fracturing area;

[0046] (3) Turn on the power supply of the resistivity imager and the pump group 13 at the same time, monitor the coal body at the location of the first stage fracturing area, judge the fracturing effect, and fractur e the second stage fracturing area at the same time; after the fracturing is completed, turn off the pump group, and withdraw the rod for a certain distance to move the resistivity imager to the location of the second stage fracturing area;

[0047] (4) Repeat the above step (3) until all the holes are fractured.

[0048] The pump assembly of the present invention can improve the working efficiency. The parts not mentioned are the same as those in the first embodiment.

[0049] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A coal mine segmented hydraulic fracturing and pressure measurement equipment, comprising a resistivity imager and a segmented hydraulic fracturing device, characterized in that: The resistivity imager includes measuring electrodes, a processor, a signal processing module, and a display and control system. The measuring electrodes and processor are installed on the staged hydraulic fracturing equipment and connected to the display and control system via cables or wireless signals. The signal processing module is installed inside the display and control system. During construction, the staged hydraulic fracturing equipment performs fracturing detection through the resistivity imager and transmits the signal to the display and control system.

2. The coal mine segmented hydraulic fracturing and pressure-monitoring equipment according to claim 1, characterized in that: The staged hydraulic fracturing equipment includes a fracturing component, a high-pressure hose, a pump group, and a water tank; the fracturing component includes a deflector, a check valve, a packer, a throttle, a packer, a safety release, and a fracturing string in sequence; the measuring electrode and the processor are installed in sequence between the deflector and the check valve.

3. A coal mine segmented hydraulic fracturing and pressure-monitoring equipment according to claim 2, characterized in that: The fracturing pipe string is connected to a high-pressure hose via a union joint.

4. The coal mine segmented hydraulic fracturing and pressure-monitoring equipment according to claim 2, characterized in that: The high-pressure rubber hose is connected to a three-way valve, one end of the three-way valve is connected to the pump group and the water tank, and the other end is connected to the high-pressure gate valve; wherein the pump group and the water tank are connected via a bellows.

5. The application method of the pressure-fracturing and monitoring equipment for coal mine staged hydraulic fracturing according to any one of claims 1 to 4, characterized in that: The steps include: (1) Install the measuring electrodes and processor of the resistivity imager at the rear end of the guide inclination of the fracturing assembly in sequence, and then connect the processor to the check valve, packer, throttle, packer, safety release and fracturing string in sequence. The fracturing string is connected to the high-pressure hose through a union joint, and then connected to the three-way valve, pump group and water tank in sequence. The other end of the three-way valve is connected to the high-pressure gate valve, and the measuring electrodes and processor are connected to the display and control system; push the connected fracturing assembly to the bottom of the borehole; (2) starting the pump group to perform fracturing on the first fracturing area of ​​the borehole, and after the fracturing is completed, closing the pump group, withdrawing the rod for a certain distance, and moving the measuring electrode of the resistivity imaging instrument to the location of the first fracturing area; (3) Turn on the power supply and pump group of the resistivity imager at the same time, monitor the coal body at the location of the first stage fracturing area, judge the fracturing effect, and fractur e the second stage fracturing area at the same time; after the fracturing is completed, turn off the pump group, and withdraw the rod for a certain distance to move the resistivity imager to the location of the second stage fracturing area; (4) Repeat the above step (3) until all the holes are fractured.

6. The application method of the pressure-fracturing and monitoring equipment for coal mine staged hydraulic fracturing according to claim 5 is characterized in that: The resistivity imager is a high-resolution resistivity imager based on microresistivity imaging technology, and injects survey current through capacitive coupling between an electrode array and a formation.

7. The application method of the pressure-fracturing and monitoring equipment for coal mine staged hydraulic fracturing according to claim 6 is characterized in that: The survey current propagates in the stratum and is detected by the measuring electrodes. The processor analyzes the current and calculates the resistivity of the stratum. The signal processing module processes the resistivity and presents the crack conditions of the coal body in the monitored area on the display and control system.

8. The application method of the pressure-fracturing and monitoring equipment for coal mine staged hydraulic fracturing according to claim 5 is characterized in that: The pump group is any one of a high-pressure pump group and a variable flow pump group.

9. The application method of the pressure-fracturing and monitoring equipment for coal mine staged hydraulic fracturing according to claim 8 is characterized in that: The high-pressure pump group includes a high-pressure pump and an explosion-proof variable frequency motor. The explosion-proof variable frequency motor is connected to the high-pressure pump, and the transmission of the explosion-proof variable frequency motor drives the piston in the high-pressure pump to move, thereby forming high-pressure water.

10. The application method of the pressure-fracturing and monitoring equipment for coal mine staged hydraulic fracturing according to claim 5, characterized in that: At least two water injection units are connected in series in the variable rheological pump group, and each water injection unit includes a power end and a hydraulic end; the power end of a water injection unit in the pump group is connected through a driving shaft, and then connected through a clutch, and the other end of the clutch is connected to the power end of other water injection units through a driven shaft, and the clutch can be automatically closed and opened.

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