Fracturing flowback monitoring system and fracturing flowback monitoring method

Abstract

The invention relates to the field of oil and gas field testing, and discloses a fracturing flowback monitoring system and a fracturing flowback monitoring method. The fracturing flow-back monitoring system comprises at least one fracturing flow-back unit, a flow collecting testing unit, a control unit and a channel switching unit. The channel switching unit is used for connecting each fracturing flowback unit with the flow collecting test unit; the flow collecting test unit is used for monitoring whether any one of the at least one fracturing flow-back unit is blocked or not and discharging fracturing fluid in all the fracturing flow-back units; and the control unit is used for controlling the path switching unit to switch and select the fracturing flowback unit for monitoring whether the fracturing flowback unit is blocked or not by utilizing the flow collecting test unit. According to the system and the method, the blockage state during fracturing flowback of the platform well can be monitored in real time, blockage treatment measures can be taken in time, the intelligent degree of the monitoring process is high, and the operation cost is saved.

Description

Technical Field

[0001] The present invention relates to the field of oil and gas field testing, and in particular to a fracturing flowback monitoring system. Furthermore, the present invention also relates to a fracturing flowback monitoring method using the system. Background Art

[0002] Hydraulic fracturing is one of the most effective measures to increase the production of oil and gas reservoirs. The flowback of fracturing fluid is closely related to the effect of increasing production. In the process of fracturing fluid flowback, a series of nozzles of different sizes are required to control the post-fracturing release to achieve the purpose of increasing the primary flowback rate, increasing the post-fracturing production capacity, and preventing the backflow of proppant.

[0003] Effective fracturing flowback can reduce proppant reflux and increase post-fracturing production capacity. At present, the domestic post-fracturing flowback control generally adopts fixed nozzle throttling and manual inspection and replacement to control post-fracturing flowback; however, the flowback fluid containing solid particles can cause the nozzle to expand, clog or damage, and the manual flowback method has problems such as large workload, high cost, and untimely nozzle replacement. In the post-fracturing flowback of horizontal wells, the fluid in the well stops flowing after the nozzle is blocked, which will cause sand to settle at the heel of the horizontal section, block the horizontal wellbore, stop the flowback and production, and fail to achieve flowback by the scheduled flowback system, affecting the post-fracturing production capacity. In addition, the blockage of the horizontal wellbore requires the use of continuous tubing for sand flushing and unblocking operations, which is costly. Summary of the invention

[0004] The purpose of the present invention is to provide a fracturing flowback monitoring system and method, which can monitor the blockage status of platform well fracturing flowback in real time, which is conducive to timely taking blockage treatment measures, and the monitoring process is highly intelligent and saves operating costs.

[0005] In order to achieve the above-mentioned objectives, the first aspect of the present invention provides a fracturing backflow monitoring system, comprising at least one fracturing backflow unit, a current collecting test unit, a control unit and a path switching unit; the path switching unit is used to connect each of the fracturing backflow units with the current collecting test unit; the current collecting test unit is used to monitor whether any one of the at least one fracturing backflow units is blocked, and to discharge the fracturing fluid in all the fracturing backflow units; the control unit is used to control the path switching unit to switch and select the fracturing backflow unit that uses the current collecting test unit to monitor whether there is a blockage.

[0006] Optionally, the system further comprises a blockage warning unit provided on the fracturing flowback unit, wherein the blockage warning unit is electrically connected to the control unit and is used for collecting a corresponding abnormal flow signal of the fracturing flowback unit.

[0007] Optionally, the fracturing flowback unit includes a flowback pipeline connected to the passage switching unit, a nozzle group located on the flowback pipeline, and a flowback throttle valve located on the flowback pipeline.

[0008] Optionally, the nozzle group includes a plurality of electric nozzles arranged in parallel, and each of the electric nozzles is electrically connected to the control unit.

[0009] Optionally, the return throttle valve is located between the nozzle group and the passage switching unit.

[0010] Optionally, the blockage warning unit includes a first pressure gauge located on the return pipeline and a second pressure gauge located on the return pipeline, the first pressure gauge and the second pressure gauge are located on both sides of the nozzle group, and the abnormal flow signal is the signal difference between the first pressure gauge and the second pressure gauge.

[0011] Optionally, the first pressure gauge and the second pressure gauge are both provided with a signal conversion component for converting the pressure value into a digital quantity, and the signal conversion component is electrically connected to the control unit.

[0012] Optionally, the signal conversion component includes a dynamic pressure changer connected to the first pressure gauge or the second pressure gauge, a voltage-frequency converter connected to the dynamic pressure changer, and a PLC counter connected to the voltage-frequency converter, and the PLC counter is electrically connected to the control unit.

[0013] Optionally, the blockage warning unit includes a noise monitor located on the return pipeline, and the noise monitor is electrically connected to the control unit.

[0014] Optionally, the current collecting test unit includes a test component capable of monitoring whether there is blockage in the fracturing flowback unit and a gathering and transportation component arranged in parallel with the test component, and both the test component and the gathering and transportation component are connected to the passage switching unit.

[0015] Optionally, the test assembly includes a test channel connected to the pathway switching unit, a sand detector, a multiphase flowmeter and a test throttle valve, the sand detector, the multiphase flowmeter and the test throttle valve are sequentially arranged on the test channel, the sand detector is located at one end of the test channel close to the pathway switching unit, and the multiphase flowmeter is electrically connected to the control unit.

[0016] Optionally, the gathering and transportation component includes a gathering and transportation channel connected to the passage switching unit and a gathering and transportation throttling valve located on the gathering and transportation channel.

[0017] Optionally, the passage switching unit includes a metering multi-way valve group electrically connected to the control unit.

[0018] Optionally, the system further comprises a regulating valve group, the regulating valve group comprising a flowback valve located on each of the fracturing flowback units, a regulating pipeline connecting two adjacent fracturing flowback units, and a regulating valve located on the regulating pipeline, wherein the connection port between the regulating pipeline and the fracturing flowback unit is located between the flowback valve and the wellhead connection end of the fracturing flowback unit.

[0019] The second aspect of the present invention provides a fracturing flowback monitoring method, which includes the following steps: flowing back the fracturing fluid from the wellhead to the pathway switching unit through the fracturing flowback unit; using a control unit to control the pathway switching unit to perform switching selection, so that any one of the fracturing flowback units is monitored for blockage through a current collecting test unit, and the fracturing fluid in the remaining fracturing flowback units is transported to the current collecting test unit; and the fracturing fluid in all the fracturing flowback units is discharged using the current collecting test unit.

[0020] Optionally, the method further includes: the current collecting test unit transmits the monitored blockage signal to the control unit, so that the control unit switches the oil nozzle on the corresponding fracturing flowback unit, or cuts off the corresponding fracturing flowback unit.

[0021] Optionally, the process of cutting off the corresponding fracturing flowback unit includes: using a regulating valve group to close the fracturing flowback unit with a blockage signal, and transporting the fracturing fluid in the fracturing flowback unit to an adjacent fracturing flowback unit.

[0022] Optionally, the blockage signal is a multiphase flow signal.

[0023] Optionally, the method also includes: during the fracturing return flow process, using a blockage warning unit to collect an abnormal flow signal of the fracturing return flow unit, and the control unit controls the pathway switching unit to switch and select the corresponding fracturing return flow unit according to the abnormal flow signal, so as to use the current collecting test unit to monitor whether there is a blockage.

[0024] Optionally, the abnormal flow signal is a pressure difference signal on both sides of the oil nozzle of the fracturing flowback unit and / or a noise signal in the fracturing flowback unit.

[0025] Through the above technical scheme, the fracturing backflow monitoring system provided by the present invention utilizes the cooperation of the collecting flow test unit, the control unit and the passage switching unit to monitor in real time whether there is a blockage in the fracturing backflow unit, which is beneficial for the operator or the control unit to timely replace, switch or cut off the backflow blockage and other measures, thereby realizing the smooth operation of the fracturing fluid backflow, reducing the proppant reflux, improving the post-fracturing production capacity, and effectively solving the problem of platform well fracturing backflow status detection; at the same time, the system can be connected with the remote command platform through the control unit to realize intelligent operation of the monitoring process, which can effectively reduce the labor cost investment and save the operating cost; the fracturing backflow monitoring system and method provide an efficient and intelligent solution for the fracturing backflow of multiple wells on the platform.

[0026] In a preferred embodiment, the fracturing return flow unit adopts a nozzle group and a return flow throttle valve for throttling control, the passage switching unit adopts a metering multi-way valve group, and corresponding throttling valves are arranged on the test channel and the gathering and transportation channel, so that the system can perform multi-well throttling measurement and control and flow metering, further effectively solving the problems of effective throttling and throttling state detection after platform well fracturing, and has the advantages of integrated throttling control and flow metering, and miniaturization of skid-mounted devices.

[0027] Other advantages of the present invention and the technical effects of the preferred embodiments will be further described in the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0029] Figure 1 It is a structural schematic diagram of a specific implementation of the fracturing flowback monitoring system in the present invention.

[0030] Description of Reference Numerals

[0031] 1-fracturing flowback unit, 11-flowback pipeline, 12-nozzle group, 13-flowback throttle valve, 14-first pressure gauge, 15-second pressure gauge, 16-noise monitor, 17-flowback electric control valve;

[0032] 2-flow collection test unit, 21-test channel, 22-sand detector, 23-multiphase flow meter, 24-test throttle valve, 25-collection channel, 26-collection throttle valve;

[0033] 3- Control unit;

[0034] 4-channel switching unit;

[0035] 5- regulating valve group, 51- return valve, 52- regulating pipeline, 53- regulating valve. DETAILED DESCRIPTION

[0036] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0037] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connection" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, it can be abutment, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features.

[0039] In a basic embodiment of the present invention, see Figure 1 The fracturing backflow monitoring system includes at least one fracturing backflow unit 1, a current collecting test unit 2, a control unit 3 and a path switching unit 4; the path switching unit 4 is used to connect each fracturing backflow unit 1 with the current collecting test unit 2; the current collecting test unit 2 is used to monitor whether any one of the at least one fracturing backflow units 1 is blocked, and discharge the fracturing fluid in all the fracturing backflow units 1; the control unit 3 is used to control the path switching unit 4 to switch and select the fracturing backflow unit 1 that uses the current collecting test unit 2 to monitor whether there is a blockage.

[0040] In the present invention, the control unit 3 can adopt a conventional control system in the art, dock with the remote command platform, and the control unit 3 and the passage switching unit 4 are connected by conventional sensors or controllers in the art, so that the control unit 3 can control the passage switching unit 4 to perform switching selection and other operations, realize intelligent operation of the monitoring and operation process, and effectively reduce labor cost investment and save operation cost. The current collecting test unit 2 can judge the blockage state in the fracturing return unit 1 through flow monitoring. When the return fracturing fluid containing solid phase particles is blocked, the liquid production will fluctuate and decrease, so that the current collecting test unit 2 forms a corresponding blockage signal; the blockage described in the present invention mainly refers to the blockage of the oil nozzle in the fracturing return unit 1, and the oil nozzle can be replaced or switched when there is blockage.

[0041] In the present invention, the fracturing return flow unit 1 can be set as one or more. In order to better explain the coordination process between the fracturing return flow unit 1, the current collecting test unit 2, the control unit 3 and the path switching unit 4, the following will be described in detail with the fracturing return flow unit 1 being set as multiple; therefore, the fracturing return flow monitoring system is particularly suitable for multi-well fracturing return flow.

[0042] The fracturing return monitoring system provided by the basic embodiment of the present invention has the following specific use process: operate the fracturing return unit 1 to return the fracturing fluid at the wellhead to the path switching unit 4, use the control unit 3 to control the path switching unit 4 to switch and select any one of the fracturing return units 1 as the test channel, use the current collecting test unit 2 to monitor whether it is blocked (during the return process, the control unit 3 can be used to control the path switching unit 4 to switch regularly to monitor different fracturing return units 1), and transport the fracturing fluid in the remaining fracturing return units 1 to the current collecting test unit 2; then use the current collecting test unit 2 to discharge the fracturing fluid in all the fracturing return units 1; when the current collecting test unit 2 detects that the fracturing return unit 1 is blocked, it can transmit the blockage signal to the control unit 3 to determine the blockage state, and use the control unit 3 to issue a corresponding control instruction to cut off the fracturing return unit 1 or switch / replace the oil nozzle on the fracturing return unit 1, and can also convert the blockage signal into an alarm signal to remind the operator to cut off the fracturing return unit 1 or manually switch / replace the oil nozzle on the fracturing return unit 1. This process can monitor in real time whether there is blockage in the fracturing return flow unit 1, which is beneficial for the operator or the control unit 3 to replace, switch or cut off the return flow blockage in time, so as to achieve the smooth operation of the fracturing fluid return flow, reduce the backflow of the proppant, improve the post-fracturing production capacity, and effectively solve the problem of platform well fracturing return flow status detection.

[0043] In the present invention, the fracturing return unit 1 generally includes a return pipeline and a single nozzle on the pipeline, so as to use the nozzle for throttling and pressure control. When blockage is detected in the fracturing return unit 1, the fracturing return unit 1 can be cut off and the nozzle can be replaced in time. As a preferred embodiment of the fracturing return unit 1, the fracturing return unit 1 includes a return pipeline 11, a nozzle group 12 located on the return pipeline 11, and a return throttle valve 13 located on the return pipeline 11. One end of the return pipeline 11 is connected to the wellhead, and the other end is connected to the passage switching unit 4. Among them, the nozzle group 12 is composed of a plurality of (for example, 4-8) nozzles arranged in parallel on the return pipeline 11, and one of the nozzles can be opened to realize the circulation of the fracturing fluid in the return pipeline 11; when blockage is detected in the fracturing return unit 1, the nozzle working at this time can be closed and switched to the remaining spare nozzles, so as to improve the processing efficiency when the nozzle is blocked, which is conducive to the smooth operation of the fracturing fluid return.

[0044] In a preferred case, the nozzle group 12 includes a plurality of electric nozzles arranged in parallel, each of which is electrically connected to the control unit 3, so that the working state of each nozzle is controlled by the control unit 3. When the operator finds that the nozzle may fail (erosion, hole expansion or blockage) in the control unit 3 or the remote command platform (PC or mobile phone APP) connected thereto, or meets the requirements of the nozzle replacement system for switching the nozzle, the control unit 3 can be used to remotely switch to the remaining spare nozzles, and remotely switch the electric adjustable nozzles, so that the fracturing return fluid can be smoothly returned, the proppant reflux can be reduced, and the post-fracturing production capacity can be increased. Specifically, the electric nozzle can adopt an electric adjustable nozzle (high pressure 35MPa).

[0045] In the present invention, the setting of the return throttle valve 13 can further effectively throttle the fracturing fluid in the return pipeline 11 and then enter the passage switching unit 4 on the basis of the throttling and pressure control effects of the nozzle group. Preferably, the return throttle valve 13 is located between the nozzle group 12 and the passage switching unit 4.

[0046] In the present invention, an electric control valve may be provided on the end of the return flow pipeline 11 connected to the wellhead, so as to be connected to the control unit 3 to realize remote control of the return flow operation or shutdown in the return flow pipeline 11 .

[0047] As a preferred embodiment of the present invention, the system further includes a blockage warning unit provided on the fracturing return unit 1, which is electrically connected to the control unit 3 and is used to collect the abnormal flow signal of the corresponding fracturing return unit 1. The abnormal flow signal is used to warn that the fracturing return unit 1 may be blocked and transmitted to the control unit. The control unit 3 controls the path switching unit 4 to switch and select the corresponding fracturing return unit 1 as the test channel according to the abnormal flow signal, so as to further verify the blockage state of the fracturing return unit 1 by using the current collecting test unit 2.

[0048] As a preferred embodiment of the blockage warning unit, the blockage warning unit includes a first pressure gauge 14 located on the return pipeline 11 and a second pressure gauge 15 located on the return pipeline 11. The first pressure gauge 4 and the second pressure gauge 15 are located on both sides of the nozzle group 12, and the flow abnormality signal is the signal difference between the first pressure gauge 4 and the second pressure gauge 15. The first pressure gauge 14 measures the pressure before the fracturing fluid passes through the nozzle group 12, which can reflect the wellhead pressure; the second pressure gauge 15 measures the pressure after the nozzle group 12. Before the blockage is formed in the nozzle, the pressure will fluctuate, and the values ​​of the first pressure gauge 14 and the second pressure gauge 15 will change greatly. The flow abnormality signal is formed by the pressure test of the two pressure gauges to warn the blockage of the nozzle on the return pipeline 11.

[0049] In order to form an abnormal flow signal that is easy to observe or to better associate it with the control unit 3, preferably, the first pressure gauge 14 and the second pressure gauge 15 are both provided with a signal conversion component that converts the pressure value into a digital quantity, and the signal conversion component is electrically connected to the control unit 3; after receiving the data of the signal conversion component, the control unit 3 can promptly control the path switching unit 4 to switch and select the corresponding fracturing return unit 1, so as to use the current collecting test unit 2 to further verify the blockage state.

[0050] Specifically, the signal conversion component includes a dynamic pressure changer connected to the first pressure gauge 14 or the second pressure gauge 15, a voltage-frequency converter connected to the dynamic pressure changer, and a PLC counter connected to the voltage-frequency converter, and the PLC counter is electrically connected to the control unit 3. At this time, the pressure value (analog value) of the first pressure gauge 14 or the second pressure gauge 15 is converted into a standard voltage value by the dynamic pressure changer, and then the voltage value is converted into the number of pulses per unit time by the voltage-frequency converter, and finally the digital value is obtained by the PLC counter, and the digital value is uploaded to the control unit 3 or the wireless remote transmission platform in real time to warn of the blockage. Among them, the dynamic pressure changer can adopt a high-frequency dynamic pressure changer, and the PLC counter can adopt a PLC high-frequency counter (frequency 100KHz).

[0051] As another preferred embodiment of the blockage warning unit, the blockage warning unit can use the noise of the return pipeline 11 as a flow abnormality signal. At this time, the blockage warning unit includes a noise monitor 16 located on the return pipeline 11, and the noise monitor 16 is electrically connected to the control unit 3. When the fracturing fluid in the return pipeline 11 is blocked, the fracturing fluid will vibrate when flowing in the return pipeline 11, and then generate noise. The noise signal in the return pipeline 11 is detected by the noise monitor 16 as a flow abnormality signal to warn whether the return pipeline 11 is blocked; when the noise monitoring finds that a certain return pipeline 11 may be blocked, the control unit 3 sends a command to the path switching unit 4 to adjust the fracturing return unit 1 to the measurement path of the current collecting test unit 2, and further verify the blockage state through the flow change. Among them, the noise monitor 16 can use a microphone, such as a low-frequency microphone.

[0052] As a preferred embodiment of the current collecting test unit 2, the current collecting test unit 2 includes a test component capable of monitoring whether there is a blockage in the fracturing return unit 1 and a collection and transportation component arranged in parallel with the test component, and both the test component and the collection and transportation component are connected to the passage switching unit 4. Any one of the fracturing return units 1 is connected to the test component through the passage switching unit 4, so that the test component is used to monitor whether there is a blockage in the fracturing return unit 1 and discharge the fracturing fluid in the unit. At the same time, the passage switching unit 4 connects the remaining fracturing return units 1 with the collection and transportation component to collect and discharge the fracturing fluid in the remaining fracturing return units 1. During operation, the passage switching unit 4 can be used to switch different fracturing return units 1 to be connected to the test component to realize the monitoring of the return status of multiple wells and ensure the smooth operation of the fracturing fluid return.

[0053] As a preferred embodiment of the test assembly, the test assembly includes a test channel 21 connected to the passage switching unit 4, a sand detector 22, a multiphase flowmeter 23 and a test throttle valve 24. The sand detector 22, the multiphase flowmeter 23 and the test throttle valve 24 are sequentially arranged on the test channel 21. The sand detector 22 is located at one end of the test channel 21 close to the passage switching unit 4, and the multiphase flowmeter 23 is electrically connected to the control unit 3. Any one of the fracturing return flow units 1 is connected to the test channel 21 through the passage switching unit 4, and the fracturing fluid in the fracturing return flow unit 1 passes through the sand detector 22, the multiphase flowmeter 23 and the test throttle valve 24 to reach the outlet of the test channel 21 for discharge; the real-time data of the sand detector 22 and the multiphase flowmeter 23 are transmitted to the control unit 3. Through the sand and flow detection analysis, when the return flow fluid containing solid phase particles is blocked in the fracturing return flow unit 1, the liquid production will fluctuate and decrease, and the blockage state in the fracturing return flow unit 1 can be judged accordingly. The test throttle valve 24 is used to further control the throttling state of the flowback fracturing fluid, thereby realizing the integration of throttling control and flow metering.

[0054] As a preferred embodiment of the gathering and transportation assembly, the gathering and transportation assembly includes a gathering and transportation channel 25 connected to the passage switching unit 4 and a gathering and transportation throttle valve 26 located on the gathering and transportation channel 25. The passage switching unit 4 connects the fracturing flowback unit 1 that is not subjected to blockage monitoring to the gathering and transportation channel 25, so that the fracturing fluid is collected in the gathering and transportation channel 25 and discharged after being throttled by the gathering and transportation throttle valve 26. The setting of the gathering and transportation throttle valve 26 is also conducive to the throttling control of the flowback fracturing fluid.

[0055] In the present invention, the outlets of the test channel 21 and the gathering channel 25 can discharge the fracturing fluid independently, or the two channel outlets can be connected to discharge the fracturing fluid together.

[0056] In the present invention, the passage switching unit 4 can be a plurality of pipelines and a plurality of valves that cooperate with each other to realize the connection state between each fracturing flowback unit 1 and the test channel 21 or the gathering and transport channel 25 in the flow collection and testing unit 2. Accordingly, the valve adopts an electronic valve to realize automatic remote control by the control unit 3. Preferably, the passage switching unit 4 includes a metering multi-way valve group electrically connected to the control unit 3, so as to realize the real-time flow metering while realizing the pipeline selection switching.

[0057] As another preferred embodiment of the present invention, the system further comprises a regulating valve group 5, which comprises a return valve 51 located on each fracturing return unit 1, a regulating pipeline 52 connecting two adjacent fracturing return units 1, and a regulating valve 53 located on the regulating pipeline 52, and the connection port of the regulating pipeline 52 and the fracturing return unit 1 is located between the return valve 51 and the wellhead connection end of the fracturing return unit 1. When the fracturing fluid is returned, the return valve 51 is generally in an open state and the regulating valve 53 is in a closed state. When the collecting flow test unit 2 detects that a certain fracturing return unit 1 is blocked, the return valve 51 on the corresponding fracturing return unit 1 can be closed to cut off, and the regulating valve 53 on the regulating pipeline 52 between the fracturing return unit 1 and the adjacent fracturing return unit 1 can be opened to return the fracturing fluid in the fracturing return unit 1 through the pipeline of the adjacent fracturing return unit 1, so as to ensure the normal return of the fracturing fluid in each wellhead. The return valve 51 and the regulating valve 53 can be controlled manually or electrically through the control unit 3. In addition, both preferably use high-pressure valves.

[0058] The second aspect of the present invention provides a fracturing backflow monitoring method, which includes the following steps: backflowing the fracturing fluid from the wellhead through the fracturing backflow unit 1 to the path switching unit 4; using the control unit 3 to control the path switching unit 4 to switch and select, so that any one of the at least one fracturing backflow units 1 is monitored for blockage through the current collecting test unit 2, and the fracturing fluid in the remaining fracturing backflow units 1 is transported to the current collecting test unit 2; and the fracturing fluid in all the fracturing backflow units 1 is discharged using the current collecting test unit 2.

[0059] According to this method, fracturing fluid return can be carried out, and the collecting current test unit 2 can be used to monitor in real time whether there is blockage in the fracturing return unit 1, which is beneficial for the operator or the control unit 3 to replace, switch or cut off the return blockage in time according to the blockage signal, so as to realize the smooth operation of fracturing fluid return.

[0060] In the present invention, the current collecting test unit 2 is preferably electrically connected to the control unit 3. At this time, the method also includes: the current collecting test unit 2 transmits the monitored blockage signal to the control unit 3, so that the control unit 3 switches the oil nozzle on the corresponding fracturing return unit 1 (when the oil nozzle group 12 is provided), or cuts off / replaces the corresponding fracturing return unit 1 (when the oil nozzle group 12 is not provided).

[0061] When the fracturing flowback monitoring system is provided with a regulating valve group 5, the process of cutting off the corresponding fracturing flowback unit 1 includes: using the regulating valve group 5 to close the fracturing flowback unit 1 with a blockage signal, and transporting the fracturing fluid in the fracturing flowback unit 1 to the adjacent fracturing flowback unit 1. The regulating valve group 5 can be manually controlled or automatically controlled by the control unit 3.

[0062] In the present invention, the data collected by the current collecting test unit 2 for blockage monitoring is preferably the data of the multiphase flow meter 23, and accordingly, the blockage signal is a multiphase flow signal.

[0063] When the fracturing return flow monitoring system is provided with a blockage warning unit, the method further includes: in the fracturing return flow process, using the blockage warning unit to collect the abnormal flow signal of the fracturing return flow unit 1, the control unit 3 controls the path switching unit 4 to switch and select the corresponding fracturing return flow unit 1 according to the abnormal flow signal, so as to use the current collecting test unit 2 to monitor whether the fracturing return flow unit 1 is blocked. The signal of the blockage warning unit is used to more accurately monitor the fracturing return flow state of the platform well, so as to ensure the continuous operation of the return flow operation.

[0064] Further preferably, the abnormal flow rate signal is a pressure difference signal on both sides of the oil nozzle of the fracturing flowback unit 1 and / or a noise signal in the fracturing flowback unit 1 .

[0065] Relatively preferred specific embodiments of the fracturing flowback monitoring system and fracturing flowback monitoring in the present invention are provided below.

[0066] As a first relatively preferred specific embodiment, the fracturing backflow monitoring system includes multiple fracturing backflow units 1, a current collecting test unit 2, a control unit 3 connected to a remote command platform, a passage switching unit 4, a blockage warning unit arranged on the fracturing backflow unit 1, and a regulating valve group 5; the fracturing backflow unit 1 includes a backflow pipeline 11, a nozzle group 12 located on the backflow pipeline 11, and a backflow throttle valve 13 located on the backflow pipeline 11. One end of the backflow pipeline 11 is provided with an electric control valve which is used to connect to the wellhead and the other end is connected to the passage switching unit 4. The nozzle group 12 includes multiple parallel valves arranged on the backflow pipeline 11. The electric nozzles are each electrically connected to the control unit 3, and the return throttle valve 13 is located between the nozzle group 12 and the passage switching unit 4; the blockage warning unit includes a first pressure gauge 14 located on the return pipeline 11 and a second pressure gauge 15 located on the return pipeline 11, the first pressure gauge 4 and the second pressure gauge 15 are located on both sides of the nozzle group 12, and the flow abnormality signal is the signal difference between the first pressure gauge 4 and the second pressure gauge 15; the first pressure gauge 14 and the second pressure gauge 15 are both provided with a signal conversion component for converting a pressure value into a digital value, and the signal conversion component includes a dynamic pressure gauge 14 or a dynamic pressure gauge 15 connected to the first pressure gauge 14 or the second pressure gauge 15. The dynamic pressure changer, a voltage-frequency converter connected to the dynamic pressure changer, and a PLC counter connected to the voltage-frequency converter, the PLC counter is electrically connected to the control unit 3; the current collecting test unit 2 includes a test component capable of monitoring whether there is a blockage in the return pipeline 11 and a collecting and transporting component arranged in parallel with the test component, the test component includes a test channel 21 connected to the passage switching unit 4, a sand detector 22, a multiphase flowmeter 23 and a test throttle valve 24, the sand detector 22, the multiphase flowmeter 23 and the test throttle valve 24 are arranged in sequence on the test channel 21, and the sand detector 22 is located in the test channel 21. Near one end of the pathway switching unit 4, the multiphase flowmeter 23 is electrically connected to the control unit 3, and the gathering and transportation assembly includes a gathering and transportation channel 25 connected to the pathway switching unit 4 and a gathering and transportation throttling valve 26 located on the gathering and transportation channel 25; the pathway switching unit 4 includes a metering multi-way valve group (using a multi-way rotating metering valve) electrically connected to the control unit 3; the regulating valve group 5 includes a return valve 51 located on each fracturing return unit 1, a regulating pipeline 52 connecting two adjacent fracturing return units 1, and a regulating valve 53 located on the regulating pipeline 52, and the connection port between the regulating pipeline 52 and the fracturing return unit 1 is located between the return valve 51 and the wellhead.

[0067] Based on the first relatively preferred fracturing backflow monitoring system, when in use, the end of the backflow pipeline 11 away from the passage switching unit 4 is connected to the wellhead, and the process of fracturing backflow monitoring includes: opening the electric control valve and the backflow valve 51 on each backflow pipeline 11, closing the regulating valve 53, and after the fracturing fluid in each backflow pipeline 11 flows through the electric control valve, the pressure value I is measured by the first pressure gauge 14, and then after passing through the backflow valve 51 and the nozzle group 12, the pressure value II is measured by the second pressure gauge 15, and then after throttling through the backflow throttle valve 13, all the backflow pipelines 11 are connected to the multi-way rotary metering valve, and the multi-way rotary metering valve is controlled by the control unit 3. The metering valve is switched to select, and one of the return pipelines 11 is connected to the test channel 21, and the other return pipelines 11 are connected to the gathering channel 25, so that the fracturing fluid in the return pipeline 11 connected to the test channel 21 passes through the sand detector 22, the multiphase flowmeter 23 and the test throttle valve 24, and reaches the outlet of the test channel 21 for discharge. At the same time, the multiphase flowmeter 23 uploads data to the control unit 3 in real time, and determines whether there is blockage in the return pipeline 11 through flow detection and analysis; the fracturing fluid in the other return pipelines 11 passes through the gathering throttle valve 26 and reaches the outlet of the gathering channel 25 for discharge, thereby realizing fracturing and return to multiple wellheads;

[0068] In this process, a dynamic pressure changer is used to convert the pressure value I of the first pressure gauge 14 and the pressure value II of the second pressure gauge 15 on each return pipeline 11 into a standard voltage value, and then the voltage value is converted into the number of pulses per unit time through a voltage-frequency converter, and finally a digital quantity is obtained through a PLC counter, and the digital quantity is uploaded to the control unit 3 or the wireless remote transmission platform in real time, and whether there is a large change in the value is used as a flow abnormality signal to warn of the blockage phenomenon in the return pipeline 11; when a flow abnormality signal exists in a certain return pipeline 11, the control unit 3 controls the multi-way rotation metering valve to switch and select the return pipeline 11 to be connected with the test channel 21, so as to use the test component to further verify the blockage state in the return pipeline 11;

[0069] When it is determined that there is a blockage in the return pipeline 11 according to the data of the multiphase flowmeter 23, the control unit 3 switches the nozzle of the nozzle group 12 to the remaining spare nozzles according to the blockage signal, realizes remote switching of the electric adjustable nozzles, and allows the fracturing return fluid to be smoothly returned; or the return valve 51 on the return pipeline 11 is manually closed to cut it off, and the regulating valve 53 on the regulating pipeline 52 between the return pipeline 11 and the adjacent return pipeline 11 is opened to continue to return the fracturing fluid in the return pipeline 11 through its adjacent return pipeline 11.

[0070] As a second relatively preferred specific embodiment, the fracturing backflow monitoring system includes multiple fracturing backflow units 1, a current collection test unit 2, a control unit 3 connected to a remote command platform, a passage switching unit 4, a blockage warning unit arranged on the fracturing backflow unit 1, and a regulating valve group 5; the fracturing backflow unit 1 includes a backflow pipeline 11, a nozzle group 12 located on the backflow pipeline 11, and a backflow throttle valve 13 located on the backflow pipeline 11, one end of the backflow pipeline 11 is connected to the wellhead and is provided with an electric control valve, and the other end is connected to the passage switching unit 4, the nozzle group 12 includes multiple electric nozzles arranged in parallel on the backflow pipeline 11, each electric nozzle is electrically connected to the control unit 3, and the backflow throttle valve 13 is located between the nozzle group 12 and the passage switching unit 4; the blockage warning unit includes a noise monitor 16 located on the backflow pipeline 11, and the noise monitor 16 is electrically connected to the control unit 3; the current collection test unit 2 includes a test group capable of monitoring whether there is blockage in the backflow pipeline 11 The invention relates to a collection and transportation component and a gathering and transportation component arranged in parallel with the test component, the test component includes a test channel 21 connected to the passage switching unit 4, a sand detector 22, a multiphase flowmeter 23 and a test throttle valve 24, the sand detector 22, the multiphase flowmeter 23 and the test throttle valve 24 are arranged on the test channel 21 in sequence, the sand detector 22 is located at one end of the test channel 21 close to the passage switching unit 4, the multiphase flowmeter 23 is electrically connected to the control unit 3, the gathering and transportation component includes a gathering and transportation channel 25 connected to the passage switching unit 4 and a gathering and transportation throttle valve 26 located on the gathering and transportation channel 25; the passage switching unit 4 includes a metering multi-way valve group (using a multi-way rotating metering valve) electrically connected to the control unit 3; the regulating valve group 5 includes a return valve 51 located on each fracturing return unit 1, a regulating pipeline 52 connecting two adjacent fracturing return units 1 and a regulating valve 53 located on the regulating pipeline 52, and the connection port between the regulating pipeline 52 and the fracturing return unit 1 is located between the return valve 51 and the wellhead.

[0071] Based on the second relatively preferred fracturing backflow monitoring system, when in use, the end of the backflow pipeline 11 away from the passage switching unit 4 is connected to the wellhead, and the process of fracturing backflow monitoring includes: opening the electric control valve and the backflow valve 51 on each backflow pipeline 11, closing the regulating valve 53, and after the fracturing fluid in each backflow pipeline 11 flows through the electric control valve, the noise signal in the backflow pipeline 11 is detected by the noise monitor 16, and then after throttling through the backflow throttle valve 13, the multiple backflow pipelines 11 are all connected to the multi-way rotation metering valve, and the multi-way rotation metering valve is controlled by the control unit 3 to switch and select it. One of the return pipes 11 is connected to the test channel 21, and the other return pipes 11 are connected to the gathering channel 25, so that the fracturing fluid in the return pipe 11 connected to the test channel 21 passes through the sand detector 22, the multiphase flowmeter 23 and the test throttle valve 24, and reaches the outlet of the test channel 21 for discharge. At the same time, the multiphase flowmeter 23 uploads data to the control unit 3 in real time, and determines whether there is blockage in the return pipe 11 through flow detection and analysis; the fracturing fluid in the other return pipes 11 passes through the gathering throttle valve 26 and reaches the outlet of the gathering channel 25 for discharge, thereby realizing fracturing and return to multiple wellheads;

[0072] In this process, the noise signal of the noise monitor 16 is uploaded to the control unit 3 or the wireless remote transmission platform in real time, and the presence of noise is used as a flow abnormality signal to warn of the blockage phenomenon in the return pipeline 11; when there is a flow abnormality signal in a return pipeline 11, the control unit 3 controls the multi-way rotation metering valve to switch and select the return pipeline 11 to be connected with the test channel 21, so as to use the test component to further verify the blockage state in the return pipeline 11;

[0073] When it is determined that there is a blockage in the return pipeline 11 according to the data of the multiphase flowmeter 23, the control unit 3 switches the nozzle of the nozzle group 12 to the remaining spare nozzles according to the blockage signal, realizes remote switching of the electric adjustable nozzles, and allows the fracturing return fluid to be smoothly returned; or the return valve 51 on the return pipeline 11 is manually closed to cut it off, and the regulating valve 53 on the regulating pipeline 52 between the return pipeline 11 and the adjacent return pipeline 11 is opened to continue to return the fracturing fluid in the return pipeline 11 through its adjacent return pipeline 11.

[0074] As a third relatively preferred specific embodiment, see Figure 1The fracturing return unit 1, the current collecting test unit 2, the control unit 3 connected to the remote command platform, the passage switching unit 4, the blockage warning unit arranged on the fracturing return unit 1 and the regulating valve group 5 are all the same as the first relatively preferred specific embodiment. Two blockage warning units are arranged on the return pipeline 11 at the same time. The return pipeline 11 is provided with a noise monitor 16, a first pressure gauge 14 and a second pressure gauge 15 electrically connected to the control unit 3. The first pressure gauge 4 and the second pressure gauge 15 are located on both sides of the nozzle group 12. The flow abnormality signal is the signal difference between the first pressure gauge 4 and the second pressure gauge 15; the first pressure gauge 14 and the second pressure gauge 15 are both provided with a signal conversion component for converting a pressure value into a digital quantity. The signal conversion component includes a dynamic pressure changer connected to the first pressure gauge 14 or the second pressure gauge 15, a voltage-frequency converter connected to the dynamic pressure changer, and a PLC counter connected to the voltage-frequency converter. The PLC counter is electrically connected to the control unit 3.

[0075] Based on the third relatively preferred fracturing backflow monitoring system, its fracturing backflow monitoring process is the same as the first relatively preferred specific embodiment, wherein the abnormal flow signal of the blockage phenomenon in the warning backflow pipeline 11 includes two signals: the pressure difference between the first pressure gauge 14 and the second pressure gauge 15, and the noise detected by the noise monitor 16.

[0076] The fracturing backflow monitoring system provided by the present invention utilizes the cooperation of the collecting flow test unit 2, the control unit 3 and the passage switching unit 4 to monitor in real time whether there is a blockage in the fracturing backflow unit 1, which is beneficial for the operator or the control unit 3 to timely replace, switch or cut off the backflow blockage and other measures, thereby realizing the smooth operation of the fracturing fluid backflow, reducing the proppant reflux, improving the post-fracturing production capacity, and effectively solving the problem of platform well fracturing backflow status detection; at the same time, the system can be connected with the remote command platform through the control unit 3 to realize intelligent operation of the monitoring process, which can effectively reduce the labor cost investment and save the operating cost; the fracturing backflow monitoring system and method provide an efficient and intelligent solution for the fracturing backflow of multiple wells on the platform.

[0077] In a preferred embodiment, the fracturing return flow unit 1 adopts a nozzle group 12 and a return flow throttle valve 13 for throttling control, the passage switching unit 4 adopts a metering multi-way valve group, and corresponding throttling valves are arranged on the test channel 21 and the gathering and transportation channel 25, so that the system can perform multi-well throttling measurement and control and flow metering, further effectively solving the problems of effective throttling and throttling state detection after platform well fracturing, and has the advantages of integrated throttling control and flow metering, and miniaturization of skid-mounted devices.

[0078] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0079] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations. In addition, the various different embodiments of the present invention can also be combined arbitrarily, as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A fracturing flowback monitoring system, It is characterized in that It comprises at least one fracturing flowback unit (1), a current collection test unit (2), a control unit (3) and a passage switching unit (4); The passage switching unit (4) is used to connect each of the fracturing flowback units (1) with the current collecting test unit (2); The current collecting test unit (2) is used to monitor whether any one of the at least one fracturing flowback units (1) is blocked, and to discharge the fracturing fluid in all the fracturing flowback units (1); The control unit (3) is used to control the passage switching unit (4) to switch and select the fracturing flowback unit (1) to monitor whether there is a blockage using the current collecting test unit (2).

2. The fracturing flowback monitoring system according to claim 1, It is characterized in that The system further comprises a blockage warning unit arranged on the fracturing flowback unit (1), the blockage warning unit being electrically connected to the control unit (3), and the blockage warning unit being used to collect a corresponding abnormal flow signal of the fracturing flowback unit (1).

3. The fracturing flowback monitoring system according to claim 2, It is characterized in that The fracturing flowback unit (1) comprises a flowback pipeline (11) connected to the passage switching unit (4), a nozzle group (12) located on the flowback pipeline (11), and a flowback throttle valve (13) located on the flowback pipeline (11).

4. The fracturing flowback monitoring system according to claim 3, It is characterized in that The nozzle group (12) comprises a plurality of electric nozzles arranged in parallel, and each of the electric nozzles is electrically connected to the control unit (3).

5. The fracturing flowback monitoring system according to claim 3, It is characterized in that The return throttle valve (13) is located between the oil nozzle group (12) and the passage switching unit (4).

6. The fracturing flowback monitoring system according to claim 3, It is characterized in that The blockage warning unit comprises a first pressure gauge (14) located on the return pipeline (11) and a second pressure gauge (15) located on the return pipeline (11), the first pressure gauge (4) and the second pressure gauge (15) being located on both sides of the nozzle group (12), and the abnormal flow signal being a signal difference between the first pressure gauge (4) and the second pressure gauge (15).

7. The fracturing flowback monitoring system according to claim 6, It is characterized in that The first pressure gauge (14) and the second pressure gauge (15) are both provided with a signal conversion component for converting a pressure value into a digital quantity, and the signal conversion component is electrically connected to the control unit (3).

8. The fracturing flowback monitoring system according to claim 7, It is characterized in that The signal conversion component comprises a dynamic pressure changer connected to the first pressure gauge (14) or the second pressure gauge (15), a voltage-frequency converter connected to the dynamic pressure changer, and a PLC counter connected to the voltage-frequency converter, wherein the PLC counter is electrically connected to the control unit (3).

9. The fracturing flowback monitoring system according to claim 3, It is characterized in that The blockage warning unit comprises a noise monitor (16) located on the return pipeline (11), and the noise monitor (16) is electrically connected to the control unit (3).

10. The fracturing flowback monitoring system according to any one of claims 1 to 9, It is characterized in that The current collecting test unit (2) comprises a test component capable of monitoring whether there is a blockage in the fracturing flowback unit (1) and a collecting and transporting component arranged in parallel with the test component, and both the test component and the collecting and transporting component are connected to the passage switching unit (4).

11. The fracturing flowback monitoring system according to claim 10, It is characterized in that The test assembly comprises a test channel (21) connected to the passage switching unit (4), a sand detection device (22), a multiphase flow meter (23) and a test throttle valve (24); the sand detection device (22), the multiphase flow meter (23) and the test throttle valve (24) are arranged in sequence on the test channel (21); the sand detection device (22) is located at one end of the test channel (21) close to the passage switching unit (4); and the multiphase flow meter (23) is electrically connected to the control unit (3).

12. The fracturing flowback monitoring system according to claim 10, It is characterized in that The gathering and transportation component comprises a gathering and transportation channel (25) connected to the passage switching unit (4) and a gathering and transportation throttling valve (26) located on the gathering and transportation channel (25).

13. The fracturing flowback monitoring system according to any one of claims 1 to 9, It is characterized in that The passage switching unit (4) comprises a metering multi-way valve group electrically connected to the control unit (3).

14. The fracturing flowback monitoring system according to any one of claims 1 to 9, It is characterized in that The system further comprises a regulating valve group (5), wherein the regulating valve group (5) comprises a flowback valve (51) located on each of the fracturing flowback units (1), a regulating pipeline (52) connecting two adjacent fracturing flowback units (1), and a regulating valve (53) located on the regulating pipeline (52), wherein the connection port between the regulating pipeline (52) and the fracturing flowback unit (1) is located between the flowback valve (51) and the wellhead connection end of the fracturing flowback unit (1).

15. A method for monitoring fracturing flowback, It is characterized in that The method comprises the following steps: The fracturing fluid is returned from the wellhead through the fracturing return unit (1) to the passage switching unit (4); The control unit (3) is used to control the passage switching unit (4) to switch and select, so that any one of the at least one fracturing flowback units (1) is monitored by the current collecting test unit (2) to see whether there is a blockage, and the fracturing fluid in the remaining fracturing flowback units (1) is transported to the current collecting test unit (2); The collecting and testing unit (2) is used to discharge the fracturing fluid in all the fracturing flowback units (1).

16. The method for monitoring fracturing flowback according to claim 15, It is characterized in that The method further comprises: the collecting current test unit (2) transmits the monitored blockage signal to the control unit (3), so that the control unit (3) switches the oil nozzle on the corresponding fracturing flowback unit (1), or cuts off the corresponding fracturing flowback unit (1).

17. The method for monitoring fracturing flowback according to claim 16, It is characterized in that The process of cutting off the corresponding fracturing flowback unit (1) comprises: using a regulating valve group (5) to close the fracturing flowback unit (1) with a blockage signal, and transporting the fracturing fluid in the fracturing flowback unit (1) to an adjacent fracturing flowback unit (1).

18. The method for monitoring fracturing flowback according to claim 16, It is characterized in that The blockage signal is a multiphase flow signal.

19. The fracturing flowback monitoring method according to any one of claims 15 to 18, It is characterized in that The method further comprises: in the fracturing flowback process, using a blockage warning unit to collect an abnormal flow signal of the fracturing flowback unit (1), the control unit (3) controlling the passage switching unit (4) to switch and select the corresponding fracturing flowback unit (1) according to the abnormal flow signal, so as to use the current collecting test unit (2) to monitor whether there is a blockage.

20. The fracturing flowback monitoring method according to claim 19, It is characterized in that The abnormal flow rate signal is a pressure difference signal on both sides of the oil nozzle of the fracturing flowback unit (1) and / or a noise signal inside the fracturing flowback unit (1).

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