Pressure wave generation method and device for intelligent flow allocation of layered water injection well

Abstract

The invention belongs to the field of oil field intelligent water injection, and particularly relates to a pressure wave generation method and device for intelligent flow allocation of a layered water injection well. 1, in a water injection mode, a manual gate connected with an upstream pipe column is opened, the upstream pipe column provides high-pressure incoming water for the system, an electric control valve and a manual valve are closed, an electromagnetic valve and the manual gate are opened, and the electric control valve operates in a steady flow mode; 2, when pressure wave data are transmitted, the electric regulating valve is in a pressure stabilizing mode, the electric regulating valve of a pressure wave regulating pipeline is opened, the controller receives a signal of the upper computer and then conducts an electromagnetic valve loop to close the electromagnetic valve, and all high-pressure water flow is injected into a wellhead through the electric regulating valve; 3, the upper computer calculates the opening degree corresponding to the pressure loss value of the valve according to the water injection parameters, after the opening degree value is rapidly adjusted, the pressure wave amplitude value is finely adjusted through a PID algorithm, when the pressure difference value reaches a set value, the upper computer sends instruction control data to the controller, and after binary coding is conducted by the controller, the electromagnetic valve is controlled to be opened and closed to form pressure waves with the set frequency.

Description

Technical Field

[0001] The present invention belongs to the field of intelligent water injection in oil fields, and particularly relates to a pressure wave generation method and device for intelligent flow allocation of stratified injection wells. Background Art

[0002] At present, intelligent water injection technology mainly uses cables for downhole equipment communication. The well depth of injection wells is generally over a thousand meters. There are some technical problems in the process of lowering the injection module and the cable into the well: First, inadequate protection of the cable during downhole operations can cause the cable to break or short-circuit, resulting in the failure of the downhole injection module. According to the statistical data of Daqing Oilfield, cable problems account for 22% of the failed intelligent injection wells. Second, when installing the cable-connected intelligent injection module downhole, the connection and protection of the cable result in low construction efficiency and high operation costs, especially significant in offshore construction operations. Third, during downhole operations, it is often necessary to operate under pressure, and it is difficult to achieve good sealing between the cable and the pipe string, causing well water to overflow and polluting the environment.

[0003] Existing wireless data transmission methods: 1. Electromagnetic waves. Due to the corrosion of the injection pipe string by well water and its rough surface, the reflection effect of electromagnetic waves is affected, and the absorption of electromagnetic waves by metals makes it difficult to transmit data over long distances. 2. Ultrasonic waves. Due to the different densities of the pipe string and the formation, energy attenuation and changes in the transmission direction occur. Currently, the propagation distance in the well is about 600m, and relays are required for long well section transmission. 3. Wireless data transmission technology of pressure waves in the injection pipe string.

[0004] Currently, the main pressure wave data transmission methods are as follows: 1. By setting a control box, combining the signals of a pressure sensor and an electromagnetic flowmeter to generate an action instruction, and sending the action instruction to an actuator to establish a pressure wave signal. 2. Using the ground main control to cooperate with the flow regulation unit to establish a pressure wave signal for downhole equipment wave code communication. 3. Installing a solenoid valve bypass at the back end of the stratified water injection system, connecting the bypass outlet to an open container, and generating a pressure wave signal by changing the injection pressure through the conduction of the solenoid valve in the bypass.

[0005] In the above data transmission methods, the single pressure wave data transmission cycle of Method 1 is as long as several hours, and the impact on the water injection volume of the water well during pressure wave data transmission is relatively high. Therefore, Method 1 is unreliable; due to the differences in the well depths of injection wells, the pressure wave attenuation and transmission time are different, the downhole pressure signal is too weak, and the pressure sensor cannot receive the signal. If the signal is too strong, it will cause a strong water hammer, and when the pressure wave frequency is fixed, the pressure wave on the wellhead is prone to interference with the downhole reflection wave. Therefore, Method 2 is unreliable; when using negative pressure wave communication during water injection in a water well, it is easy to cause the fluid in the downhole injector to backflow, resulting in downhole fouling, water nozzle blockage and other problems. Connecting the bypass outlet end to an open container is prone to environmental pollution and difficult to control. Therefore, Method 3 is also unreliable. Summary of the Invention

[0006] The object of the present invention is to address the technical problems existing in the existing pressure wave communication technology method, such as long data transmission cycle, fixed pressure wave amplitude and frequency, non-environmental protection, and easy underground pollution. A pressure wave data transmission system with high-pressure tightness is provided, a method for adjusting the amplitude and frequency of the pressure wave is provided, the control accuracy and efficiency of the pressure wave are improved, and a pressure wave generation method and device for intelligent flow allocation of layered injection wells with long service life and low cost are provided.

[0007] The technical solution adopted by the present invention is as follows: A pressure wave generation method and device for intelligent flow allocation of layered injection wells, characterized in that: the pressure wave generation device includes a host computer (1), a controller (2), a parallel pipeline (22), an electric linear regulating valve (14), a manual valve (12), a solenoid valve (9), a water outlet side pressure transmitter (15), an electric flow regulator (21), a manual gate (3), and a manual gate (16); the right end of the parallel pipeline (22) is installed with an electric flow regulator and a manual gate (3), and the two are connected by a flange. The left end of the parallel pipeline (22) is connected to the manual gate (16) through a flange, and the manual gate (16) is connected to the injection pipeline.

[0008] The host computer (1) includes a data acquisition and transmission function, and acquires data from the pressure transmitter (6), the pressure transmitter (15), and the electromagnetic flowmeter (4).

[0009] The controller (2) is composed of a single-chip microcomputer (18) and a relay (20). It receives the data sent by the host computer (1), processes the data, and controls the on-off of the relay (20) contacts, thereby controlling the opening and closing of the solenoid valve (9) to generate a pressure wave.

[0010] The electric flow regulator (21) is composed of an electric regulating valve (5), an electromagnetic flowmeter (4), and a pressure transmitter (6). Its built-in constant voltage and constant current operation mode can be connected to the host computer (1) through its own RS485 communication interface to realize data communication and constant voltage and constant current mode switching.

[0011] The pressure transmitters (6)(15) are internally provided with RS485 communication circuits. The water outlet side pressure transmitter (15) of the parallel pipeline (22) communicates directly with the host computer (1), and the water inlet side pressure transmitter (6) can share data with the electric flow regulator (21) and then the host computer (1) acquires the data.

[0012] The electromagnetic flowmeter (4) is internally provided with an RS485 communication circuit. It can share real-time flow data with the electric flow regulator (21) and then the host computer (1) acquires the data.

[0013] The parallel pipeline (22) consists of a pressure wave generating pipeline (8), an intermediate pipeline (11), and a pressure wave regulating pipeline (13). The pressure wave is generated by the cooperation of the parallel pipeline and the valve action.

[0014] The pressure wave regulating pipeline (13) is connected to the electric linear regulating valve (14) through a flange in the middle part of the pipeline, and both sides are connected to the lower parallel pipelines (11) and (8) through right-angle bend pipelines.

[0015] The intermediate pipeline (11) is connected to the manual valve (12) through a flange in the middle part of the pipeline, and both sides are connected in parallel with the pressure wave generating pipeline (8) and the pressure wave regulating pipeline (13) through tees.

[0016] The pressure wave generating pipeline (8) is connected to the solenoid valve (9) through a flange in the middle part of the pipeline. The upper ends of the tees (7) and (10) on both sides are connected to the parallel pipeline (11) and the pressure wave regulating pipeline (13). The left end of the tee (10) is connected to the pressure gauge (15), and the tee (7) is connected to the right-end pressure gauge (6).

[0017] The water injection station provides the incoming water pressure for the pressure wave generating device through the pipeline. The water inlet of the manual gate (3) is connected to the pipeline of the water injection station, and the water outlet of the manual gate (3) is connected to the electric flow regulating instrument (21). The electric flow regulating instrument (21) consists of an electromagnetic flowmeter (4), an electric regulating valve (5), and a pressure transmitter (6), and they are connected by flanges in between.

[0018] The rear end of the electric flow regulating instrument (21) is connected to the parallel pipeline (22) through the pipeline of the tee (7), and is in the same straight line as the pressure wave generating pipeline (8).

[0019] The rear end of the parallel pipeline (22) is connected to the pressure transmitter (15) and the manual gate (16). The manual gate (16) is connected to the stratified water injection string (17) through the water injection pipeline. In the normal water injection mode and the pressure wave generating working mode, the entire intelligent flow allocation pressure wave generating device for the stratified water injection well establishes a complete high-pressure sealed water injection pipeline, and in the water injection mode, the electric regulating valve (5) controls the injection parameters of the system and automatically adjusts the opening of the valve according to the flow rate and pressure conditions. When transmitting the pressure wave data, the opening of the electric regulating valve (5) is fixed. After the electric linear regulating valve (14) of the pressure wave regulating pipeline (13) adjusts the opening to generate an appropriate pressure loss, the solenoid valve (9) opens and closes regularly to form the pressure wave data transmission of the sealed system.

[0020] According to the pressure wave generating method and device for intelligent flow allocation of the stratified water injection well described in claim 1, the measurement method includes the following steps:

[0021] Step 1: Establish a high-pressure and stable flow water supply channel;

[0022] The method for forming a high-pressure and stable-flow water supply channel is as follows:

[0023] Open the manual gate (3) connected to the upstream pipe string, close the electric linear regulating valve (14) and the manual valve (12), and open the solenoid valve (9) and the manual gate (16). The system is supplied with high-pressure water from the upstream pipe string. After powering on the electric flow regulator (21), in the normal water injection mode, the host computer (1) sets the electric regulating valve (5) to the stable-flow working mode through RS485 communication and sets the water injection flow value. In the stable-flow water injection mode, the electric flow regulator (21) collects the flow value of the electromagnetic flowmeter (4) and the pressure value of the pressure transmitter (6), and uses the PID algorithm to achieve closed-loop stable control of the water injection flow based on the real-time feedback of the flow and pressure according to the set flow, providing a stable injection flow under the stable-flow water injection condition.

[0024] Step 2: Establish the pipeline conditions for generating pressure waves;

[0025] The method for forming the pipeline conditions for generating pressure waves is as follows:

[0026] When pressure wave data is transmitted, the system switches to the pressure wave data transmission mode. The host computer (1) sends a control signal, sets the electric regulating valve (5) to the constant-pressure mode, sets the pressure to the current water injection pressure value, and opens the electric linear regulating valve (14). In the constant-pressure mode, the electric flow regulator (21) continuously collects the pressure value of the pressure transmitter (6) and the flow value of the electromagnetic flowmeter (4), and uses the PID algorithm to continuously adjust the opening of the electric regulating valve (5) according to the set flow, providing a stable injection flow. After receiving the signal from the host computer (1), the controller (2) outputs a high level to close the relay, thereby conducting the solenoid valve circuit and closing the solenoid valve (9). At this time, all the high-pressure water flows through the electric regulating valve (14) and is injected into the wellhead (17) through the manual gate (16).

[0027] Step 3: Calculate the opening of the electric linear regulating valve (14) according to the pressure wave amplitude set by the user;

[0028] The method for calculating the opening of the electric linear regulating valve (14) is as follows:

[0029] After the user inputs and confirms the pressure wave amplitude in the host computer (1), the host computer (1) saves the pressure wave amplitude data, establishes a calculation model based on the pressure wave amplitude data and the pipeline parameters, confirms the current opening of the electric linear regulating valve (14) and the opening value x to be adjusted, combines the total pressure loss value ΔP3 of the parallel pipeline, the frictional loss along the way ΔP f and the pressure loss formula ΔP of the linear regulating valve l , and establishes the following expression for the required opening x of the electric linear regulating valve:

[0030]

[0031] Wherein, ΔP is the amplitude of the pressure wave set by the user, ρ is the density of the liquid in the injection well, v2 is the liquid flow velocity in the electric linear regulating valve, K0 is the resistance coefficient when the electric linear regulating valve is fully open, and ΔP f is the frictional loss of the pressure along the way, x is the valve opening, and ΔP3 is the total pressure loss value of the parallel pipeline of the electric linear regulating valve and the solenoid valve.

[0032] According to the set length of the injection water pipeline, as well as the parameter information of the inner diameter and material in the upper computer (1), the frictional loss ΔP along the way is calculated by the Darcy - Weisbach equation f The expression is as follows:

[0033]

[0034] Wherein, f is the friction coefficient of the injection water pipeline, L is the length of the injection water pipeline, ρ is the density of the liquid in the injection well, v1 is the liquid flow velocity in the injection well, and D is the diameter of the injection water pipeline; the expression of the pipeline friction coefficient f is as follows:

[0035]

[0036] Wherein: ε is the absolute roughness, D is the pipeline diameter, and Re is the Reynolds number; since this calculation is for the flow environment in the injection string, the Reynolds number range is satisfied: 5000 ≤ Re ≤ 10 8 (turbulent flow region), and the relative roughness range is: 10 -6 ≤ ε / D ≤ 0.05. According to the improved equation of Swamee - Jain, the pipeline friction coefficient can be implicitly rewritten as:

[0037]

[0038] When the electric linear regulating valve (14) and the solenoid valve (9) in the parallel pipeline are opened simultaneously, according to the principle of similarity between water and electricity, the expression of the total pressure loss value ΔP3 of the parallel pipeline is:

[0039]

[0040] Wherein: ΔP l is the pressure loss of the electric linear regulating valve, and ΔP2 is the pressure loss when the solenoid valve is fully open;

[0041] The pressure loss formula ΔP of the electric linear regulating valve (14) l The expression is:

[0042]

[0043] Wherein, K0 is the resistance coefficient when the linear valve is fully open, x is the valve opening, ρ is the liquid density, and v2 is the liquid flow velocity in the valve.

[0044] The expression of the pressure loss formula ΔP2 when the solenoid valve (9) is fully open is:

[0045]

[0046] In the formula, K1 is the resistance coefficient when the electromagnetic valve is fully open, ρ is the liquid density, and v3 is the liquid flow velocity.

[0047] Step 4: After the PID algorithm is used to finely adjust the pressure loss value, the host computer (1) controls the opening and closing of the solenoid valve (9) to transmit the pressure wave data;

[0048] The method for the host computer (1) to send pressure wave pulse data to control the opening and closing of the solenoid valve (9) for data transmission after the differential pressure is finely adjusted by PID is as follows:

[0049] The host computer (1) quickly adjusts the opening of the electric linear regulating valve (14) to the target position according to the obtained opening value and then performs fine adjustment by PID. The host computer (1) collects the pressures of the pressure transmitter (6) and the pressure transmitter (15), and calculates the pressure difference formed at both ends of the parallel pipeline (22). When the error is outside the set range, the host computer (1) automatically adjusts the flow area of the electric linear regulating valve (14) according to the pressure difference and the set value until the set pressure wave amplitude value is formed. When the pressure wave amplitude reaches the preset threshold, the electric linear regulating valve (14) automatically switches to the constant pressure control mode. The host computer (1) system collects the pipeline pressure data in real time through the pressure transmitter (15), performs closed-loop adjustment on the pressure deviation based on the PID algorithm, and realizes the constant control of the pipeline pressure loss by dynamically adjusting the valve body opening. When the conditions meet the system working requirements, the host computer (1) sends a data control instruction to the controller (2), and the controller (2) performs binary encoding to form complete downhole pressure wave data including the well number, layer number, nozzle opening, and start and end bits. The output high and low levels control the solenoid valve (9) to open and close at the data frequency set by the host computer to form a pressure wave with the set frequency and amplitude.

[0050] The object of the present invention is to solve the technical problems existing in the existing pressure wave technology methods, such as long data transmission period, fixed pressure wave amplitude and frequency, non-environmental protection, and easy to cause downhole pollution. It provides a high-pressure closed pressure wave data transmission system, provides a method for adjusting the pressure wave amplitude and frequency, improves the control accuracy and efficiency of the pressure wave, and has a long service life and low cost, a pressure wave generation method and device for intelligent flow allocation of stratified injection wells.

[0051] Advantages of the present invention: The data transmission period of the pressure wave is shortened, and the problems that the amplitude-frequency of the pressure wave is fixed and cannot adapt to different downhole working conditions, and the existing pressure wave method is not environmentally friendly and is prone to cause downhole pollution and requires special containers are overcome. A pressure wave generation method and device for intelligent flow allocation of stratified injection wells are provided. Its main advantages are as follows:

[0052] (1) A valve pressure loss calculation method capable of quickly adjusting the pressure wave amplitude is proposed. By combining the opening calculation with the PID model, the single-pressure wave water injection period can be controlled within minutes, reducing the impact of pressure wave water injection on the oil well output.

[0053] (2) A pressure wave generation method with adjustable pressure wave amplitude is proposed. For different depths and working conditions of injection wells, different pressure wave amplitudes can be selected to ensure the accurate identification of the pressure wave by downhole tools.

[0054] (3) A pressure wave generation method with adjustable pressure wave frequency is proposed. For different injection wells, the interval of the pressure wave is adjusted to reduce the interference between pressure waves, and a stable pressure wave is provided for downhole tools in different situations to improve the identification ability of downhole tools.

[0055] (4) A high-speed pressure wave data transmission method is proposed. By designing a parallel pipeline structure and cooperating with solenoid valves and regulating valves, the single pressure wave time is reduced from several minutes to several seconds.

[0056] (5) A pressure wave generation device and method compatible with the existing water injection function are proposed, making the system highly integrated and the system with the existing water injection function have a wider application range.

[0057] (6) The intelligent flow allocation pressure wave generation device system for stratified injection wells establishes a complete high-pressure closed injection pipeline, and establishes a complete high-pressure pipeline water injection and pressure wave generation device, without any bypass containers and having no impact on the environment. Description of the Drawings

[0058] Figure 1 Structural schematic diagram of the pressure wave generation device for intelligent flow allocation of stratified injection wells;

[0059] Description of the reference numerals:

[0060] 1 - Host computer 2 - Controller 3 - Manual gate

[0061] 4 - Electromagnetic flowmeter 5 - Electric control valve 6 - Pressure transmitter

[0062] 7 - Three-way joint 8 - Pressure wave generation pipeline 9 - Solenoid valve

[0063] 10 - Three-way joint 11 - Parallel pipeline 12 - Manual valve

[0064] 13 - Pressure wave regulating pipeline 14 - Electric linear control valve 15 - Pressure transmitter

[0065] 16 - Manual gate 17 - Stratified water injection string 18 - Single-chip microcomputer

[0066] 19 - Control signal 20 - Relay 21 - Electric flow regulator

[0067] 22 - Parallel string

[0068] Figure 2 It is a controller circuit for the upper computer containing a single-chip microcomputer to control the opening and closing of the solenoid valve.

[0069] Figure 3 It is the working flowchart of the pressure wave generating device for intelligent flow allocation of stratified water injection wells.

[0070] Figure 4 It is the binary control command sequence converted by the controller after receiving the data from the upper computer.

[0071] Figure 5 It is to collect the downhole pressure data with a downhole pressure wave amplitude of 0.1 MPa and a pressure wave interval of 5 s.

[0072] Figure 6 It is to collect the downhole pressure data with a downhole pressure wave amplitude of 0.2 MPa and a pressure wave interval of 7 s. Specific implementation mode

[0073] Example 1

[0074] Refer to Figure 1-2 , the technical solution adopted by the present invention is: a pressure wave generating method and device for intelligent flow allocation of stratified water injection wells, characterized in that: the pressure wave generating device includes an upper computer (1), a controller (2), a parallel pipeline (22), an electric linear control valve (14), a manual valve (12), a solenoid valve (9), an outlet side pressure transmitter (15), an electric flow regulator (21), a manual gate (3), a manual gate (16); the right end of the parallel pipeline (22) is installed with an electric flow regulator and a manual gate (3), and the two are connected by a flange. The left end of the parallel pipeline (22) is connected to the manual gate (16) by a flange, and the manual gate (16) is connected to the water injection pipeline.

[0075] The upper computer includes a data acquisition and transmission function, acquires the data of the pressure transmitter (6), the pressure transmitter (15), and the electromagnetic flowmeter (4), and sets the control operation mode of the electric flow regulator and the pressure wave data output control of the controller.

[0076] The controller consists of a single-chip microcomputer (18) and a relay (20). It receives the data sent by the host computer (1), processes the data, and then controls the on / off of the relay (20) contacts to control the opening and closing of the solenoid valve (9) to generate a pressure wave.

[0077] The electric flow regulator (21) consists of an electric control valve (5), an electromagnetic flowmeter (4), and a pressure transmitter (6). Its built-in constant voltage and constant current operation mode can be connected to the host computer (1) through its own RS485 communication interface to achieve data communication and constant voltage and constant current mode switching.

[0078] The pressure transmitters (6)(15) use M20×1.5 external thread interfaces, with a pressure resistance value of 25 MPa and an accuracy class of 0.5FS. It has an RS485 communication circuit. The pressure transmitter (15) on the water outlet side of the parallel pipeline (22) communicates directly with the host computer (1), and the pressure transmitter (6) on the water inlet side can share data with the electric flow regulator (21) and then the host computer (1) collects the data.

[0079] The electromagnetic flowmeter (4) has a pressure resistance value of 25 MPa, a flow velocity grade of 0.5 m / s to 10 m / s, an accuracy of 0.5FS, a DN40 diameter, and an internal RS485 communication circuit. It can share real-time flow data with the electric flow regulator (21) and then the host computer (1) collects the data.

[0080] The parallel pipeline (22) consists of a pressure wave generating pipeline (8), an intermediate pipeline (11), and a pressure wave regulating pipeline (13). The pipeline diameter is 40 mm, and the pressure wave is generated by the cooperation of the parallel pipeline and the valve action.

[0081] The pressure wave regulating pipeline (13) is connected to the electric linear control valve (14) through a flange in the middle of the pipeline, and both sides are connected to the lower parallel pipelines (11) and (8) through right-angle bend pipelines.

[0082] The intermediate pipeline (11) is connected to the manual valve (12) through a flange in the middle of the pipeline. The manual valve diameter is DN40mm, and both sides are connected in parallel with the pressure wave generating pipeline (8) and the pressure wave regulating pipeline (13) through tees.

[0083] The pressure wave generating pipeline (8) is connected to the solenoid valve (9) through a flange in the middle of the pipeline. The upper ends of the tees (7) and (10) on both sides are connected to the parallel pipeline (11) and the pressure wave regulating pipeline (13). The left end of the tee (10) is connected to the pressure gauge (15), and the right end of the tee (7) is connected to the pressure gauge (6).

[0084] The water injection station provides the incoming water pressure for the pressure wave generating device through pipelines. The water inlet of the manual gate (3) is connected to the pipeline of the water injection station, and the water outlet of the manual gate (3) is connected to the electric flow regulator (1). The electric flow regulator (21) consists of an electromagnetic flowmeter (4), an electric control valve (5) and a pressure transmitter (6), which are connected by flanges.

[0085] The rear end of the electric flow regulator (21) is connected to the parallel pipeline (22) through a tee pipeline (7), and is in the same straight line as the pressure wave generating pipeline (8).

[0086] The rear end of the parallel pipeline (22) is connected to a pressure transmitter (15) and a manual gate (16). The manual gate (16) is connected to the stratified water injection string (17) through a water injection pipeline. In the normal water injection mode and the pressure wave generating working mode, the intelligent flow allocation pressure wave generating device for the stratified water injection well establishes a complete high-pressure sealed water injection pipeline, and in the water injection mode, the electric control valve (5) controls the injection parameters of the system, and automatically adjusts the opening of the valve according to the flow rate and pressure conditions. When transmitting pressure wave data, the opening of the electric control valve (5) is fixed. After the electric linear control valve (14) on the pressure wave regulating pipeline (13) adjusts the opening to generate an appropriate pressure loss, the solenoid valve (9) opens and closes regularly to form the pressure wave data transmission of the sealed system.

[0087] Embodiment 2

[0088] Referring to Figure 3 , a pressure wave generating method and device for intelligent flow allocation of a stratified water injection well, the pressure wave generating method for flow allocation includes the following steps:

[0089] Step 1: Establish a high-pressure and steady-flow water supply channel;

[0090] The method for forming the high-pressure and steady-flow water supply channel is as follows:

[0091] Open the manual gate (3) connected to the upstream string, close the electric linear control valve (14) and the manual valve (12), and open the solenoid valve (9) and the manual gate (16). The system is supplied with high-pressure incoming water from the upstream string. After powering on the electric flow regulator (21), in the normal water injection mode, the upper computer (1) sets the electric control valve (5) to the steady-flow working mode through RS485 communication and sets the water injection flow rate value. In the steady-flow water injection mode, the electric flow regulator (21) collects the flow rate value of the electromagnetic flowmeter (4) and the pressure value of the pressure transmitter (6), and uses the PID algorithm to realize the closed-loop stable control of the water injection flow rate based on the real-time feedback of the flow rate and pressure according to the set flow rate, so as to provide a stable injection flow rate under the steady-flow water injection condition.

[0092] Step 2: Establish the pipeline conditions for generating pressure waves;

[0093] The method for forming the pipeline conditions for generating pressure waves is as follows:

[0094] When pressure wave data is transmitted, the system switches to the pressure wave data transmission mode. The host computer (1) sends a control signal to set the electric control valve (5) to the constant pressure mode, set the pressure to the current water injection pressure value, and open the electric linear control valve (14). In the constant pressure mode, the electric flow regulator (21) continuously collects the pressure value of the pressure transmitter (6) and the flow value of the electromagnetic flowmeter (4), and uses the PID algorithm to continuously adjust the opening of the electric control valve (5) according to the set flow rate to provide a stable injection flow rate. After receiving the signal from the host computer (1), the controller (2) outputs a high level to close the relay, thereby conducting the solenoid valve circuit and closing the solenoid valve (9). At this time, all the high-pressure water flow passes through the electric control valve (14) and is injected into the wellhead (17) through the manual gate (16).

[0095] Step 3: Calculate the opening of the electric linear control valve (14) according to the pressure wave amplitude set by the user;

[0096] The method for calculating the opening of the electric linear control valve (14) is as follows:

[0097] After the user inputs the pressure wave amplitude in the host computer (1) and confirms it, the host computer (1) saves the pressure wave amplitude data, establishes a calculation model based on the pressure wave amplitude data and pipeline parameters, confirms the current opening of the electric linear control valve (14) and the required adjusted opening value x, combines the total pressure loss value ΔP3 of the parallel pipeline, and the frictional loss along the way ΔP f and the pressure loss formula of the linear control valve ΔP l , and establish the following expression for the required opening x of the electric linear control valve:

[0098]

[0099] In the formula, ΔP is the pressure wave amplitude set by the user, ρ is the liquid density of the injection well, v2 is the liquid flow velocity in the electric linear control valve, K0 is the resistance coefficient when the electric linear control valve is fully open, ΔP f is the frictional loss of the pressure along the way, x is the valve opening, and ΔP3 is the total pressure loss value of the parallel pipeline of the electric linear control valve and the solenoid valve.

[0100] According to the length of the water injection pipeline set in the host computer (1), as well as the parameter information of the inner diameter and material, the expression for calculating the frictional loss along the way ΔP f is as follows:

[0101]

[0102] Wherein, f is the friction coefficient of the water injection pipeline, L is the length of the water injection pipeline, ρ is the density of the liquid in the water injection well, v1 is the flow velocity of the liquid in the water injection well, and D is the diameter of the water injection pipe; the expression of the pipeline friction coefficient f is as follows:

[0103]

[0104] Wherein: ε is the absolute roughness, D is the pipeline diameter, and Re is the Reynolds number; since the calculation this time is for the flow environment in the water injection pipe string, the Reynolds number range is satisfied: 5000 ≤ Re ≤ 10 8 (turbulent flow region), and the relative roughness range is: 10 -6 ≤ ε / D ≤ 0.05. According to the improved equation of Swamee-Jain, the pipeline friction coefficient can be implicitly rewritten as:

[0105]

[0106] When the electric linear regulating valve (14) and the solenoid valve (9) in the parallel pipeline are opened simultaneously, according to the principle of similarity between water and electricity, the expression of the total pressure loss value ΔP3 of the parallel pipeline is:

[0107]

[0108] Wherein: ΔP l is the pressure loss of the electric linear regulating valve, and ΔP2 is the pressure loss when the solenoid valve is fully open;

[0109] The pressure loss formula ΔP of the electric linear regulating valve (14) l The expression is:

[0110]

[0111] Wherein, K0 is the resistance coefficient when the linear valve is fully open, x is the valve opening, ρ is the liquid density, and v2 is the flow velocity of the liquid in the valve.

[0112] The expression of the pressure loss formula ΔP2 when the solenoid valve (9) is fully open is:

[0113]

[0114] Wherein, K1 is the resistance coefficient when the solenoid valve is fully open, ρ is the liquid density, and v3 is the flow velocity of the liquid.

[0115] Step 4: After the PID algorithm is used for fine adjustment of the pressure loss value, the host computer (1) controls the opening and closing of the solenoid valve (9) to transmit the pressure wave data;

[0116] The method for the host computer (1) to send pressure wave pulse data to control the opening and closing of the solenoid valve (9) for data transmission after the PID is used for fine adjustment of the pressure difference is as follows:

[0117] The host computer (1) quickly adjusts the opening of the electric linear regulating valve (14) to the target position according to the required opening value, and then performs fine adjustment of PID. The host computer (1) collects the pressures of the pressure transmitter (6) and the pressure transmitter (15), and calculates the pressure difference formed at both ends of the parallel pipeline (22). When the error is outside the set range, the host computer (1) automatically adjusts the flow area of the electric linear regulating valve (14) according to the pressure difference and the set value until the set pressure wave amplitude value is formed. When the pressure wave amplitude reaches the preset threshold, the electric linear regulating valve (14) automatically switches to the voltage stabilization control mode. The host computer (1) system collects the pipeline pressure data in real time through the pressure transmitter (15), performs closed-loop adjustment on the pressure deviation based on the PID algorithm, and realizes the constant control of the pipeline pressure loss by dynamically adjusting the valve body opening. When the conditions meet the system working requirements, the host computer (1) sends a data control instruction to the controller (2), and the controller (2) performs binary coding to form complete downhole pressure wave data including the well number, layer number, nozzle opening, start bit and end bit. The output high and low levels control the solenoid valve (9) to open and close according to the data frequency set by the host computer to form a pressure wave with the set frequency amplitude.

[0118] Refer to Figure 4-5 , to verify the rationality of the method flow of this device, a pressure wave amplitude-frequency adjustment and downhole data reception experiment was carried out. The experimental process and conditions are as follows: the injection flow rate of the experiment is 100 m 3 / day, and the stable injection pressure downhole is 10.3 MPa. For this experiment, the downhole pressure wave amplitude is designed to be 0.1 MPa, the pressure wave interval is 5 s, the downhole pressure wave amplitude is 0.2 MPa, and the pressure wave interval is 7 s. Figure 4 The experimental data shows that when the well number is 2, the layer number is 2, and the nozzle opening is 90%, the controller (2) converts the control command of the host computer (1) into a binary coded pressure wave sequence 1010010010010110100101.

[0119] When the amplitude of the downhole pressure wave is 0.1 MPa, the upper computer (1) calculates that the amplitude of the surface pressure wave is 0.21 MPa according to the water injection parameters, adjusts the opening degree x of the electric linear regulating valve (14) to 14.3%, quickly adjusts the valve to the target position, and then performs fine adjustment of PID. The upper computer (1) collects the pressures of the pressure transmitter (6) and the pressure transmitter (15), and calculates the pressure difference formed at both ends of the parallel pipeline. When the error is outside the set range, the upper computer (1) automatically adjusts the flow area of the electric linear regulating valve (14) according to the pressure difference and the set value until the set pressure wave amplitude value is formed. When the pressure wave amplitude reaches the target value, the adjustment time of the electric linear regulating valve (14) is within 1 min, and the time used is only 1 / 3 of that of the PID adjustment method used alone. When the pressure wave amplitude meets the system working requirements, the upper computer (1) sends command control data to the controller (2), and the controller (2) performs binary coding to form 22-bit complete downhole pressure wave data including well number, layer number, nozzle opening degree, start bit and end bit. The experimental data is: 1010010010010110100101, and the measured change curve of the downhole pressure with time is as Figure 5 shown.

[0120] When the amplitude of the downhole pressure wave is 0.2 MPa, the upper computer (1) calculates that the amplitude of the surface pressure wave is 0.31 MPa according to the water injection parameters, the opening degree x of the electric linear regulating valve (14) is 8.3%, quickly adjusts the valve to the target position, and then performs fine adjustment of PID. The upper computer (1) collects the pressures of the pressure transmitter (6) and the pressure transmitter (15), and calculates the pressure difference formed at both ends of the parallel pipeline. When the error is outside the set range, the upper computer (1) automatically adjusts the flow area of the electric linear regulating valve (14) according to the pressure difference and the set value until the set pressure wave amplitude value is formed. The measured valve adjustment time is generally within 1 min. When it meets the system working requirements, the upper computer (1) sends command control data to the controller (2), and the controller (2) performs binary coding to form 22-bit complete downhole pressure wave data including well number, layer number, nozzle opening degree, start bit and end bit. The output high and low levels control the solenoid valve (9) to open and close at intervals of 7 s according to the data sent by the upper computer to form a pressure wave with the set frequency. The experimental data is: 1010010010010110100101, and the measured change curve of the downhole pressure with time at a pressure wave amplitude of 0.2 MPa is as Figure 6 shown.

[0121] In this experiment, a complete high-pressure pipeline water injection and pressure wave generating device was established. Without any bypass containers and without any impact on the environment, the downlink of pressure wave data with different amplitudes and frequencies was realized. From Figure 5 、 6It can be seen that under the conditions of a pressure wave amplitude of 0.1 MPa, a data width of 5 s, and a data width of 7 s for 0.2 MPa, the downhole pressure signal changes synchronously with the ground pressure signal. The change of the downhole pressure signal is consistent with the ground command pressure wave sequence, and the downhole pressure wave amplitude is the same as the designed value. This shows that when the calculated ground pressure wave value is transmitted to the downhole through the pressure wave command formed by the opening and closing of the solenoid valve, the downhole pressure wave amplitude can be made consistent with the set value.

[0122] In the design of the pressure wave generator combining the solenoid valve and the parallel pipeline in this time, the time of a single pulse wave only needs several seconds, and the total data transmission time does not exceed 5 min, which is only 1 / 12 of the time required by the existing pulse data transmission method (about 1 h). The impact of the improvement of this efficiency on the injection volume of the injection well is greatly reduced. When the pulse time lasts for 1 h, according to the existing method of relieving pressure through the bypass, the injection volume is reduced from 30 m 3 / d to 15 m 3 / d, and each time a frame of data is sent, the injection well will be under-injected by 0.6 m 3 , and long-term use will have a greater impact on the injection volume of the injection well.

[0123] Therefore, it can be proved that the pressure wave generation method and device for intelligent flow allocation of stratified injection wells of the present invention can adjust the pressure wave amplitude and frequency according to different injection conditions, improve the transmission efficiency of the pressure wave, and reduce the impact on the injection volume of the water well. It is compatible with the injection function on the ground and establishes a complete high-pressure closed water injection pipeline without any impact on the environment.

[0124] The present invention can not only be connected to each module through the RS485 data line, but also communicate with each module through the wireless transmission method, and can also achieve the purpose of system control and data transmission.

[0125] It should be noted that all directional indications (such as up, down, left, right, front, back...) in this embodiment are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the attached drawings). If the specific posture changes, the directional indication will also change accordingly.

Claims

1. A pressure wave generation method and device for intelligent flow allocation of stratified injection wells, characterized in that, The pressure wave generating device comprises the following parts: A host computer (1), a controller (2), a parallel pipeline (22), an electric linear regulating valve (14), a manual valve (12), a solenoid valve (9), a pressure transmitter (15) on the water outlet side, an electric flow regulating instrument (21), a manual gate (3), and a manual gate (16); the right end of the parallel pipeline (22) is installed with an electric flow regulating instrument and a manual gate (3), and the two are connected by a flange; the left end of the parallel pipeline (22) is connected to the manual gate (16) by a flange, and the manual gate (16) is connected to the water injection pipeline; The host computer (1) includes a data acquisition and sending function, and acquires data of the pressure transmitter (6), the pressure transmitter (15), and the electromagnetic flowmeter (4); The controller (2) is composed of a single-chip microcomputer (18) and a relay (20). It receives the data sent by the host computer (1), processes the data, and controls the on-off of the relay (20) contacts, thereby controlling the opening and closing of the solenoid valve (9) to generate a pressure wave; The electric flow regulating instrument (21) is composed of an electric regulating valve (5), an electromagnetic flowmeter (4), and a pressure transmitter (6); its built-in constant voltage and constant current operation mode can be connected to the host computer (1) through its own RS485 communication interface to realize data communication and constant voltage and constant current mode switching; The pressure transmitter (6) internally has an RS485 communication circuit. The pressure transmitter (15) on the water outlet side of the parallel pipeline (22) communicates directly with the host computer (1), and the pressure transmitter (6) on the water inlet side can share data with the electric flow regulating instrument (21) and then the host computer (1) acquires the data; The electromagnetic flowmeter (4) internally has an RS485 communication circuit. It can share real-time flow data with the electric flow regulating instrument (21) and then the host computer (1) acquires the data; The parallel pipeline (22) is composed of a pressure wave generating pipeline (8), an intermediate pipeline (11), and a pressure wave regulating pipeline (13). The pressure wave is generated by the cooperation of the parallel pipeline and the valve action; The pressure wave regulating pipeline (13) is connected to the electric linear regulating valve (14) in the middle of the pipeline by a flange, and both sides are connected to the lower parallel pipelines (11) and (8) through right-angle bend pipelines; The intermediate pipeline (11) is connected to the manual valve (12) in the middle of the pipeline by a flange, and both sides are connected in parallel with the pressure wave generating pipeline (8) and the pressure wave regulating pipeline (13) through tees; The pressure wave generating pipeline (8) is connected to the solenoid valve (9) in the middle of the pipeline by a flange. The upper ends of the tees (7) and (10) on both sides are connected to the parallel pipeline (11) and the pressure wave regulating pipeline (13). The left end of the tee (10) is connected to the pressure gauge (15), and the tee (7) is connected to the right-end pressure gauge (6); The water injection station provides the incoming water pressure for the pressure wave generating device through a pipeline. The water inlet of the manual gate (3) is connected to the pipeline of the water injection station, and the water outlet of the manual gate (3) is connected to the electric flow regulating instrument (21); the electric flow regulating instrument (21) is composed of an electromagnetic flowmeter (4), an electric regulating valve (5), and a pressure transmitter (6), and they are connected by flanges in between; The rear end of the electric flow regulator (21) is connected to the parallel pipeline (22) through a tee (7) pipeline and is on the same straight line as the pressure wave generating pipeline (8). The rear end of the parallel pipeline (22) is connected to a pressure transmitter (15) and a manual gate (16). The manual gate (16) is connected to the stratified water injection pipe string (17) through a water injection pipeline. In the normal water injection mode and the pressure wave generating working mode, the intelligent flow allocation pressure wave generating device for the stratified water injection well establishes a complete high-pressure closed water injection pipeline. And in the water injection mode, the injection parameters of the electric control valve (5) control system are adjusted, and the opening of the valve is automatically adjusted according to the flow rate and pressure conditions. When transmitting pressure wave data, the opening of the electric control valve (5) is fixed. After the electric linear control valve (14) on the pressure wave regulating pipeline (13) adjusts the opening to generate an appropriate pressure loss, the solenoid valve (9) regularly opens and closes to form the pressure wave data transmission of the closed system.

2. The pressure wave generating method and device for intelligent flow allocation of the stratified water injection well according to claim 1, wherein the measurement method comprises the following steps: Step 1: Establish a high-pressure and stable flow water supply channel. Open the manual gate (3) connected to the upstream pipe string, close the electric linear control valve (14) and the manual valve (12), and open the solenoid valve (9) and the manual gate (16). The system is supplied with high-pressure water from the upstream pipe string. After powering on the electric flow regulator, in the normal water injection mode, the upper computer (1) sets the electric control valve (5) to the stable flow working mode through RS485 communication and sets the water injection flow rate value. In the stable flow water injection mode, the electric flow regulator collects the flow rate value of the electromagnetic flowmeter (4) and the pressure value of the pressure transmitter (6), and uses the PID algorithm to realize the closed-loop stable control of the water injection flow rate based on the real-time feedback of the flow rate and pressure according to the set flow rate, so as to provide a stable injection flow rate under the stable flow water injection condition. Step 2: Establish the pipeline conditions for generating pressure waves. When transmitting pressure wave data, the system switches to the pressure wave data transmission mode. The upper computer (1) sends a control signal, sets the electric control valve (5) to the voltage stabilization mode, sets the pressure to the current water injection pressure value, and opens the electric linear control valve (14). In the voltage stabilization mode, the electric flow regulator continuously collects the pressure value of the pressure transmitter (6) and the flow rate value of the electromagnetic flowmeter (4), and uses the PID algorithm to continuously adjust the opening of the electric control valve according to the set flow rate to provide a stable injection flow rate. After receiving the signal from the upper computer (1), the controller (2) outputs a high level to close the relay, thereby conducting the solenoid valve circuit and closing the solenoid valve (9). All the high-pressure water flows through the electric linear control valve (14) and is injected into the wellhead (17) through the manual gate (16). Step 3: Calculate the opening of the electric linear control valve according to the pressure wave amplitude set by the user. After inputting the pressure wave amplitude in the host computer and confirming, the host computer saves the pressure wave amplitude data, establishes a calculation model based on the pressure wave amplitude data and pipeline parameters, confirms the current opening degree of the electric linear regulating valve and the required opening degree value x, combines the total pressure loss value ΔP3 of the parallel pipeline, and the frictional loss along the way ΔP f and the pressure loss formula ΔP of the linear regulating valve l , the expression for the required opening degree x of the electric linear regulating valve is established as follows: where ΔP is the amplitude of the pressure wave set by the user, ρ is the density of the liquid in the injection well, v2 is the liquid flow velocity in the electric linear control valve, K0 is the resistance coefficient when the electric linear control valve is fully open, and ΔP f is the frictional pressure loss along the way, x is the valve opening, and ΔP3 is the total pressure loss value of the parallel pipeline of the electric linear control valve and the solenoid valve; According to the length of the water injection pipeline set in the host computer, as well as the parameter information of the inner diameter and material, the frictional loss ΔP along the way is calculated by the Darcy - Weisbach equation f The expression is as follows: In the formula, f is the friction coefficient of the water injection pipeline, L is the length of the water injection pipeline, ρ is the density of the liquid in the water injection well, v1 is the flow velocity of the liquid in the water injection well, and D is the diameter of the water injection pipe. The expression of the pipeline friction coefficient f is as follows: Where ε is the absolute roughness, D is the pipe diameter, and Re is the Reynolds number. According to the improved equation of Swamee-Jain, the pipe friction coefficient can be implicitly rewritten as: When the electric linear regulating valve and the solenoid valve in the parallel pipeline are opened simultaneously, according to the principle of similarity between water and electricity, the expression for the total pressure loss value ΔP3 of the parallel pipeline is: where ΔP l is the pressure loss of the electric linear control valve, and ΔP2 is the pressure loss when the solenoid valve is fully open; Pressure loss formula ΔP of the electric linear control valve l The expression is as follows: Where K0 is the resistance coefficient when the linear valve is fully open, x is the valve opening, ρ is the liquid density, and v2 is the liquid flow velocity inside the valve; The expression for the pressure loss formula ΔP2 when the solenoid valve is fully open is: Where K1 is the resistance coefficient when the solenoid valve is fully open, ρ is the liquid density, and v3 is the liquid flow velocity; Step 4: After the fine adjustment of the pressure loss value by the PID algorithm, the upper computer controls the opening and closing of the solenoid valve to transmit the pressure wave data; The upper computer quickly adjusts the valve to the target position according to the obtained opening value and then performs fine adjustment of the PID. The upper computer (1) collects the pressures of the pressure transmitter (6) and the pressure transmitter (15), and calculates the pressure difference formed at both ends of the parallel pipeline; when the error is outside the set range, the upper computer automatically adjusts the flow area of the electric linear regulating valve (14) according to the pressure difference and the set value until the set pressure wave amplitude value is formed; when the pressure wave amplitude reaches the preset threshold, the electric linear regulating valve (14) automatically switches to the voltage stabilization control mode; the upper computer system collects the pipeline pressure data in real time through the pressure transmitter (15), performs closed-loop adjustment on the pressure deviation based on the PID algorithm, and realizes the constant control of the pipeline pressure loss by dynamically adjusting the valve body opening; when the conditions meet the system working requirements, the upper computer sends a data control instruction to the controller (2), and the controller (2) performs binary encoding to form complete downhole pressure wave data including the well number, layer number, nozzle opening, and start and end bits; outputs high and low levels to control the solenoid valve (9) to open and close according to the data frequency set by the upper computer to form a pressure wave with the set frequency and amplitude.

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