A water injection control system and method for a water injection well

Abstract

The application discloses a water injection control system for a water injection well, comprising: a mobile-sub limiting device arranged at a well head, used for releasing a mobile-sub when receiving an activation instruction; a ground water delivery device, an outlet of which is communicated with an internal space of the mobile-sub limiting device, used for injecting water into the well through the mobile-sub limiting device; a mobile-sub, used for receiving water distribution instructions for water distribution control of each downhole water distribution device in a water distribution condition, entering a water injection string with water flow after being released, and floating to the well head after data collection; each water distribution device is arranged at a target layer and installed outside a side wall of a string, used for monitoring production data of the target layer, and exchanging the production data with water distribution instructions carried by the mobile-sub when detecting the mobile-sub, so as to use the water distribution instructions for water distribution control. The application shortens the distance of data transmission and signal control, is weakly interfered by environment, and is faster and more stable in data exchange.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas field development, and in particular to a water injection control system and method for a water injection well. BACKGROUND

[0002] In the later stage of oilfield development, water injection development is an important means to supplement energy for the formation. However, due to the existence of interlayer contradictions in the oil reservoir, general water injection can cause uneven water absorption between layers, and cannot achieve good water flooding effect. Therefore, the layered water injection technology is particularly important. The layered water injection technology has gone through the development stages of fixed layered water injection, movable layered water injection, eccentric layered water injection, bridge type concentric layered water injection, and the latest generation of intelligent layered water injection.

[0003] Conventional layered water injection needs to use wireline operation to realize layered control, which is time-consuming and low in efficiency. The downhole intelligent control equipment is mostly powered and data transmitted by cable, and the process of tripping in and out is complex and the operation cost is high. The existing downhole intelligent water injection device generally uses electromagnetic waves or pressure pulses for command control and data transmission, which is greatly affected by the wellbore and formation environment, and has poor adaptability to complex and deep reservoirs and complex wellbore structures. Therefore, it is more necessary to invent a downhole intelligent data transmission method with small environmental influence and high data transmission efficiency, and a matched intelligent water injection system with high stability, low operation construction difficulty, low operation cost and no frequent maintenance.

[0004] Therefore, the prior art needs to provide a water injection control scheme for a water injection well, so as to effectively solve one or more of the above technical problems. SUMMARY

[0005] In order to solve the above technical problems, the present application provides a water injection control system for a water injection well, comprising: a son limit device arranged at a wellhead, for releasing a son when receiving an activation instruction; a ground water delivery device, the outlet of which is in communication with the internal space of the son limit device, for water injection downhole through the son limit device; the son, for receiving water distribution instructions for water distribution control of each downhole water distribution device in a water distribution condition, and entering a water injection string with water flow after being released, and floating to the wellhead after completing data collection; a plurality of downhole water distribution devices, each water distribution device being arranged at a target layer and installed outside the side wall of the water injection string, for monitoring production data of the target layer, and exchanging the production data with the water distribution instructions about itself carried by the son when detecting the son, to utilize the water distribution instructions for water distribution control.

[0006] Preferably, the sub-limits device comprises: a wellhead device in communication with the outlet of the ground water delivery device, the bottom of which is in communication with the wellhead, for providing a wellhead accommodation space for the sub; a capture device arranged at the upper end of the wellhead device, for limiting, fixing, controlling and releasing the sub; a wellhead signal exchange device arranged outside the wellhead device and installed on the capture device, for prompting the sub to obtain the water distribution instruction and read all production data collected by the sub by communicating with the sub.

[0007] Preferably, the wellhead signal exchange device also communicates with the capture device, for sending the activation instruction to the capture device in the water distribution working condition, and detecting in real time whether the sub is close to the capture device, and generating a capture instruction when the sub is detected, so as to send the capture instruction to the capture device.

[0008] Preferably, the sub comprises: a pressure-bearing shell; a first signal transceiver device arranged inside the pressure-bearing shell, for continuously emitting a first detection signal; a first data storage and processing device arranged inside the pressure-bearing shell and connected with the first signal transceiver device, for wireless communication with the current downhole water distribution device to realize information exchange of water distribution instruction and production data when the sub is close to the corresponding target water distribution layer under the cooperation of the first signal transceiver device; a lightweight insulating filling part arranged inside the pressure-bearing shell.

[0009] Preferably, the downhole water distribution device comprises: a water distribution nipple body arranged on the sidewall of the water injection string, the water distribution nipple body being provided with an upper interface and a lower interface at both ends; a water injection outlet in communication with the water injection string, the water injection outlet being arranged on the sidewall of the water distribution nipple body; a second signal transceiver device; a second data storage and processing device connected with the second signal transceiver device, for wireless communication with the sub when the first detection signal is detected, so as to realize information exchange of water distribution instruction and production data; and a power device connected with the water injection outlet and the second data storage and processing device, for regulating the flow rate and / or outlet diameter of the water injection outlet under the control of the water distribution instruction.

[0010] Preferably, the water injection regulation system further comprises: an anti-overflow collection device arranged at the bottom of the wellbore, for limiting the sub at the bottom of the well after the sub passes through all the downhole water distribution devices with water flow.

[0011] Preferably, the surface water delivery device comprises: a first water injection pipeline, an outlet of which is in communication with the sidewall of the wellhead equipment in the mobile-sub limiting device, for being in communication with the wellhead equipment in the water injection mode and not in communication with the sidewall of the wellhead equipment in the water distribution mode; a second water injection pipeline, a first end of which is in communication with the sidewall of the first water injection pipeline, a second end of which is in communication with the sidewall of the wellhead equipment in the mobile-sub limiting device, for being in communication with the wellhead equipment in the water distribution mode.

[0012] Preferably, the surface water delivery device further comprises: a first injection valve near the inlet of the first water injection pipeline; a second injection valve arranged in the second water injection pipeline; a third injection valve near the outlet of the first water injection pipeline.

[0013] Preferably, the mobile-sub limiting device is further used for monitoring the dynamic pressure of the internal space of the device to determine the timing of the mobile-sub reaching the bottom of the wellbore, and based on this, a water injection stop command is generated to make the water injection device stop water injection.

[0014] In another aspect, a water injection control method for a water injection well is provided, which is implemented by using the water injection control system as described above, wherein the water injection control method comprises: communicating the surface water delivery device with the mobile-sub limiting device, and injecting water downhole through the mobile-sub limiting device; in the water distribution mode, the mobile-sub receives a water distribution command for water distribution control of each downhole water distribution device; the mobile-sub limiting device is used to release the mobile-sub when an activation command is received, so that the mobile-sub enters the water injection string after being released; each downhole water distribution device arranged at the target layer and installed outside the sidewall of the water injection string is used to monitor production data of the target layer, and when the mobile-sub is detected, the production data is exchanged with the water distribution command about the mobile-sub carried by the mobile-sub for water distribution control; and the mobile-sub floats to the wellhead after completing data collection.

[0015] Compared with the prior art, one or more embodiments in the above solution can have the following advantages or beneficial effects:

[0016] The application provides a water injection control system and method for a water injection well.

[0017] Additional features and advantages of the application will be set forth in the description that follows, and in part will be apparent from the description, or can be learned by practice of the application. The objectives and other advantages of the application will be realized and attained by the structure particularly pointed out in the written description and claims thereof as well as the appended drawings. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings:

[0019] Figure 1 It is a whole structure schematic view of the water injection control system for a water injection well of the embodiment of the application.

[0020] Figure 2 It is an application environment and specific structure schematic view of the water injection control system for a water injection well of the embodiment of the application.

[0021] Figure 3 It is a structure schematic view of a traveler in the water injection control system for a water injection well of the embodiment of the application.

[0022] Figure 4 It is a structure schematic view of a downhole water distribution device in the water injection control system for a water injection well of the embodiment of the application.

[0023] Figure 5 It is a running process schematic view of the water injection control system for a water injection well of the embodiment of the application.

[0024] Figure 6 It is a step view of the water injection control method for a water injection well of the embodiment of the application. DETAILED DESCRIPTION

[0025] The embodiments of the present application will be described in detail below with reference to the accompanying drawings and embodiments, so that how the present application applies technical means to solve technical problems and achieves technical effects can be fully understood and implemented. It should be noted that, as long as there is no conflict, each embodiment in the present application and each feature in each embodiment can be combined with each other, and the formed technical solutions are within the protection scope of the present application.

[0026] In addition, the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions. Moreover, although a logical order is shown in the flowchart, in some cases, the steps shown or described herein can be executed in an order different from that shown.

[0027] In the late stage of oilfield development, water injection development is an important means to supplement energy for the formation. However, due to the existence of interlayer contradictions in the reservoir, general water injection will cause uneven water absorption between layers, and cannot achieve good water flooding effect, so layered water injection technology is particularly important. Layered water injection technology has gone through fixed layered water injection, movable layered water injection, eccentric layered water injection, bridge concentric layered water injection, and the latest generation of intelligent layered water injection.

[0028] Conventional layered water injection needs to use wireline operation to realize layered control, which is time-consuming and low in efficiency. The downhole intelligent control equipment is mostly powered and data transmitted by cable, and the process of tripping in and out is complex and the operation cost is high. The existing downhole intelligent water injection device generally uses electromagnetic waves or pressure pulses for instruction control and data transmission, which is greatly affected by the wellbore and formation environment, and has poor adaptability to complex and deep reservoirs and complex wellbore structures. Therefore, it is more necessary to invent a downhole intelligent data transmission method with small environmental impact and high data transmission efficiency, and a matching intelligent water injection system with high stability, low operation construction difficulty, low operation cost and no frequent maintenance.

[0029] In 2019, Tan Shaoxu et al. introduced a layered water injection system for offshore platforms. The system uses downhole pressure sensors and hydraulic control sleeves to collect data in real time and control flow, realizing monitoring and data exchange between the ground and the downhole. The system uses a permanent downhole pressure gauge, which has two sensors that can detect slight pressure fluctuations, temperature fluctuations and flow fluctuations in the casing, and transmit the monitored data to the ground through a cable. However, the use of cable signal transmission tools for well operation is complex, with many pipelines, which are prone to pipeline damage, cable insulation failure and other problems, increasing the difficulty, time and cost of tripping in and out.

[0030] The "Oilfield injection well subdivision injection ball injection profile integration pipe column" of application number 201220122870.2 proposes an integrated pipe column using ball injection profile, which can control the water distribution of downhole layer injection by wellhead ball injection. However, this method can only control a specific injection volume, and the number of control times is limited, and it cannot simultaneously monitor and transmit feedback of downhole production data.

[0031] The "Cable control type intelligent layer injection device system" of application number 201821966297.7 proposes a cable control type intelligent layer injection device system. The system uses a cable to control the downhole intelligent injection distribution tool string to achieve automatic measurement and adjustment of layer injection and segmented flow during layer injection. However, the device uses a cable as an electrical signal and energy transmission medium, and the construction is more complex during the well tripping operation, and the cable is easily damaged by the environment, and the operation maintenance time is long after damage, which increases the operation and maintenance cost.

[0032] The "Water injection well pressure wave code intelligent layer injection system" of application number 201821544813.7 proposes a layer injection system using pressure wave code for control in a water injection well. The method transmits a pressure wave code to the injection channel through the wellhead, and the downhole precise flow monitoring device receives the wave code and commands the intelligent injection system to adjust the water distribution. The use of this method avoids the high operation cost problems caused by traditional steel wire and cable control and cable intelligent water distribution system, but the downhole flowmeter used in this method is unstable and easily damaged, and the well environment is complex, the pressure wave is greatly affected by the environment, resulting in large monitoring error and control difficulty, so that the signal control of this method is difficult to apply to complex wellbore and flow environment.

[0033] Therefore, in order to solve one or more of the above technical problems, the embodiments of the present application propose a water injection control system and method for a water injection well. The system and method include a ground intelligent wellhead, a ground water delivery device, a downhole intelligent layer injection distribution device, and a downhole intelligent layer injection distribution device. A specially designed signal exchange traveler that generally stays at the wellhead can move freely in the injection string during use, exchange data when moving to the intelligent measurement and adjustment device, drive the measurement and adjustment device to control the water nozzle, and simultaneously collect production monitoring data including downhole temperature and pressure, flow, etc. After completing the information exchange and production data collection tasks of all measurement and adjustment devices, the traveler returns to the wellhead quickly by buoyancy and transmits the data carried. The present application can solve the problems of existing wireless transmission measurement and adjustment devices, such as large environmental factor interference, limited use depth, etc., and has practical significance for realizing efficient and low-cost intelligent oilfields.

[0034] It should be noted that in the embodiments of the present invention, "above" and "below" are relative directions. Specifically, the direction pointing to the sky is called "above", and the direction pointing to the well is called "below".

[0035] Figure 1 This is a schematic diagram of the overall structure of a water injection control system for a water injection well, according to an embodiment of this application. Figure 1 As shown, the water injection control system for water injection wells (hereinafter referred to as the "water injection control system") described in this embodiment of the invention includes at least: a wanderer limiting device A, a surface water delivery device B, a wanderer C, and multiple downhole water distribution devices D. The wanderer limiting device A is located at the wellhead, specifically at the wellhead of the water injection tubing (water injection wellbore) 11. Furthermore, the internal space of the wanderer limiting device A is configured as a wellhead space, and the bottom (inside) of the wanderer limiting device A is connected to the wellhead of the water injection tubing 11. The surface water delivery device B is located on the surface, and its outlet is connected to the internal space of the wanderer limiting device A. This is achieved by installing packers at different well depths between the casing 12 and the water injection tubing 11 (see...). Figure 2 Packers 13 and 15 are used to separate the perforated sections within different injection layers. Each downhole water distribution device D is installed within a different injection layer. Furthermore, each downhole water distribution device D is installed in a different target layer (see...). Figure 2 The perforation sections of target layer 1 and target layer 2 (see...) Figure 2 The perforation section 13 of target layer 1 and the perforation section 16 of target layer 2 are located in the water injection string 11, and are installed around the outside of the side wall of the corresponding target layer. That is to say, a corresponding downhole water distribution device D is installed on the outside of the water injection string 11 corresponding to the perforation section in each water injection layer.

[0036] Specifically, the wanderer limiting device A is used to limit and fix the wanderer C installed at the wellhead, wherein the wanderer C is released when an activation command is received. The surface water delivery device B is used to inject water into the well through the wanderer limiting device A and the water injection string 11.

[0037] The wanderer C is used to receive water distribution commands for regulating the water distribution (volume) of each downhole water distribution device D under water distribution conditions. After being released, it enters the well with the water flow and floats to the wellhead after completing data collection, where it is limited and fixed by the wanderer limiting device A. It should be noted that in this embodiment of the invention, the water injection control system has two operating conditions: water injection condition and water distribution condition. The water distribution condition is the process of transmitting water distribution commands and collecting production data when one or more downhole water distribution devices D perform downhole water distribution and / or production data collection; the water injection condition is the process of performing water injection operations according to the water distribution parameters (including: water injection outlet flow rate and / or water injection outlet diameter) configured for the downhole water distribution device D under the water distribution condition.

[0038] Each downhole water distribution device D is used to monitor the production data of the target layer in real time, and to detect whether the rover C is close to and passes through the corresponding water distribution device D in real time. When the rover C is detected to be close to the perforated section of the corresponding target layer (when the rover 3 is detected), the production data collected and stored by the current downhole water distribution device D is exchanged with the water distribution instructions carried by the rover C about itself (the current downhole water distribution device D), so that the current downhole water distribution device D uses the obtained water distribution instructions for itself after the exchange to regulate and control the water distribution of the current injection layer section, and so that the rover C obtains the production data about itself after the exchange to complete the production data collection task for the current downhole water distribution device D.

[0039] Figure 2 The application environment and specific structure diagram of the water injection control system for injection wells in the embodiment of the present application are shown in the following figure. Figure 1 and Figure 2 The specific structure and functions of the water injection control system in the embodiment of the present application are described below.

[0040] As shown in Figure 2 , the rover limiting device A is an intelligent wellhead device of the water injection control system, and at least includes: a wellhead equipment 4, a capturing device 2 and a wellhead signal exchange device 1. The wellhead equipment 4 is connected in communication with the outlet of the ground water delivery device B, and the bottom of the wellhead equipment 4 is connected in communication with the wellhead of the water injection string 11. The capturing device 2 is arranged at the upper end of the wellhead equipment 4. The wellhead signal exchange device 1 is arranged outside the wellhead equipment 4 and is installed on the upper end surface of the capturing device 2. The ground water delivery device B is connected in communication with the water injection device (not shown), and the ground water delivery device B is a water delivery pipeline device of the water injection control system, mainly used to deliver the water stored in the water injection device to the wellhead position of the water injection string 11, so as to deliver the injected water to the downhole through the water injection string 11.

[0041] The wellhead equipment 4 is configured as a hollow shell, used to provide a wellhead accommodating space for the rover C (see component 3 in Figure 2 ). The capturing device 2 is an intelligent wellhead rover capturing device, used to control the limiting and releasing of the rover 3. The wellhead signal exchange device 1 is an intelligent wellhead signal exchange device, and communicates with the rover 3. The wellhead signal exchange device 1 is used to facilitate the rover 3 to obtain the water distribution instructions for one or more downhole water distribution devices D that need to be regulated and controlled, and to read all the production data collected by the rover, through the communication with the rover 3.

[0042] Specifically, under normal water injection conditions, the wanderer 3 is fixed at the wellhead by the capture device 2. When it is necessary to perform downhole water distribution and / or production data acquisition for one or more downhole water distribution devices, the wellhead signal exchange device 1 sends an activation command to the capture device 2, causing the capture device 2 to release the wanderer 3 under the action of the activation command.

[0043] Furthermore, in this embodiment of the invention, the wellhead signal exchange device 1 is equipped with a smart antenna. Since the wanderer 3 returns to the wellhead by its own buoyancy after completing the production data collection task of all downhole water distribution devices D, the wellhead signal exchange device 1 described in this embodiment of the invention is also used to detect the signal strength of the first detection signal emitted by the wanderer 3 in real time through the smart antenna, thereby detecting whether the wanderer 3 is approaching the capture device 2 in real time based on the diagnostic results of the signal strength. Specifically, when the wellhead signal exchange device 1 detects that the wanderer 3 is gradually approaching the capture device 2, it immediately generates a capture command and sends the capture command to the capture device 2, thereby enabling the capture device 2 to complete the wellhead limiting and fixing operation of the wanderer 3 under the action of the capture command.

[0044] Figure 3 This is a schematic diagram of the structure of the wanderer in the water injection control system for a water injection well, according to an embodiment of this application. Figure 3 As shown, the "wanderer 3," serving as an intelligent signal transceiver device in a water injection control system, includes at least: a pressure-bearing housing 301, a first signal transceiver 305, a first data storage and processing device 304, and a lightweight insulating filling part 302. The pressure-bearing housing 301 is made of pressure-bearing material and has a hollow shell structure. The first signal transceiver 305 and the first data storage and processing device 304 are both located inside the pressure-bearing housing 301, and the remaining space inside the pressure-bearing housing 301 is entirely filled with the lightweight insulating filling part 302. The first data storage and processing device 304 is electrically connected to the first signal transceiver 305, enabling communication. Furthermore, the "wanderer 3" in this embodiment also includes a first power supply device 303. The power supply device 303 provides the power required for the normal operation of the first signal transceiver 305 and the first data storage and processing device 304.

[0045] Furthermore, the intelligent signal rovers 3 constructed in this embodiment of the invention have a density less than that of water and can float freely in water with low flow velocity or in still water. Moreover, the size of the rovers 3 is slightly smaller than the cross-sectional size of the water injection string 11, allowing the rovers 3 to move up and down within the water injection string 11. Under normal water injection conditions, they can move with the water flow according to the water injection speed, thereby moving downhole through the water injection string 11.

[0046] Furthermore, the first signal transceiver 305 is used to continuously transmit the first detection signal. Preferably, the first signal transceiver 305 is also used to continuously transmit the first detection signal when an activation command is received. It should be noted that the signal strength of the first detection signal should be minimized to ensure battery life while maintaining normal communication.

[0047] Furthermore, the first data storage and processing device 304 is communicatively connected to the first signal transceiver device 305. The first data storage and processing device 304 is used, in cooperation with the first signal transceiver device 305, to wirelessly communicate with the current underground water distribution device D when approaching the underwater water distribution device D of the corresponding target water distribution layer, so as to realize the exchange of information on water distribution instructions and production data for the underground water distribution device D that is currently being passed.

[0048] Figure 4 This is a schematic diagram of the downhole water distribution device in a water injection control system for water injection wells, according to an embodiment of this application. Figure 4 As shown, in multiple downhole water distribution devices D (see...) Figure 2 In the components 9 and 10, each downhole water distribution device 9 and 10 has the same structure. Specifically, the downhole water distribution device 9 and 10 includes at least: a water distribution sub body 907, an upper interface 901, a lower interface 909, a water injection outlet 908, a second signal transceiver 904, a second data storage and processing device 903, and a power device 906.

[0049] like Figure 2 As shown, the water distribution section body 907 is mounted on the side wall of the water injection pipe string 11. (As indicated...) Figure 4 As shown, the second signal transceiver 904, the second data storage and processing device 903, and the power device 906 are all installed on the inner wall of the water distribution sub-section body 907. The second signal transceiver 904 is electrically connected to the second data storage and processing device 903, enabling communication. The water injection outlet 908 is connected to the water injection string 11 and is located on the side wall of the water distribution sub-section body 901. The water injection outlet 908 is achieved through an adjustable water nozzle. The power device 906 uses an adjustable motor. The power device 906 is also electrically connected to the water injection outlet 908 and the second data storage and processing device 903.

[0050] In addition, the downhole water distribution device 9, 10 according to the embodiment of the present application further comprises a second power supply device 902 and a production data monitoring device 905. The production data monitoring device 905 is connected with the second data storage and processing equipment 903, and is used to continuously monitor dynamic production data such as temperature, pressure and flow rate of the current injection layer, and send the obtained dynamic production data to the second data storage and processing equipment 903 for storage, so that the second data storage and processing equipment 903 directly transmits the stored dynamic production data to the first data storage and processing equipment 304 in the rover 3 for storage when information exchange is performed with the rover 3. The second power supply device 902 provides power energy required for normal operation of the production data monitoring device 905, the second signal transceiver equipment 904, the second data storage and processing equipment 903 and the power equipment 906.

[0051] Further, the second signal transceiver equipment 904 is used to detect the first detection signal in real time. Preferably, the second signal transceiver equipment 904 is further used to send the first detection signal to the second data storage and processing equipment 903 after detection. The second data storage and processing equipment 903 is in communication connection with the second signal transceiver equipment 904. The second data storage and processing equipment 903 is used to perform wireless communication with the first data storage and processing equipment 304 in the rover 3 through the first signal transceiver equipment 305 and the second signal transceiver equipment 904 when the first detection signal is detected, so as to realize information exchange of the water distribution instruction and the production data.

[0052] Further, the second data storage and processing equipment 903 is further used to detect the signal strength of the first detection signal emitted by the rover 3 in real time through the second signal transceiver equipment 904, so as to detect whether the rover 3 approaches the downhole water distribution device 9 or 10 of the current injection layer (target layer) in real time according to the diagnosis result of the signal strength. Wherein, the second data storage and processing equipment 903 is used to generate a reaching feedback signal immediately when it is detected that the rover 3 is gradually approaching the current downhole water distribution device 9 or 10 (for example, the signal strength of the first detection signal gradually increases), and transmit the reaching feedback signal to the first signal transceiver equipment 305 in the rover 3 through the second signal transceiver equipment 904. At this time, the first data storage and processing equipment 304 in the rover 3 receives the reaching feedback signal emitted by the current downhole water distribution device 9 or 10 through the first signal transceiver equipment 305, and immediately starts the information exchange task between the rover 3 and the downhole water distribution device in the current injection layer reached.

[0053] In addition, after the information exchange task between the mobile 3 and the current downhole water distribution device is completed, the power device 906 in the current downhole water distribution device is further used to receive the water distribution instruction for the current injection layer sent by the second data storage and processing device 903, and under the action of the current water distribution instruction, the rotation speed of the power device 906 and / or the outlet diameter of the injection outlet 908 are adjusted to adjust the current injection outlet flow rate and / or the outlet diameter, thereby completing the water distribution regulation task of the current injection layer. At this time, since the mobile 3 gradually moves downhole with the water flow, the second data storage and processing device 903 in the current downhole water distribution device will detect that the mobile 3 is gradually leaving the current downhole water distribution device 9 or 10 (for example, the signal strength of the first detection signal gradually decreases until the first detection signal cannot be detected), so that the mobile 3 and the current downhole water distribution device complete the information exchange task (on the one hand, the production data collection task of the current injection layer is completed, and on the other hand, the water distribution regulation task of the current injection layer is completed), and then continue to move to the next injection layer to complete the information exchange task with the downhole water distribution device in the next injection layer.

[0054] Further, after the first data storage and processing device 304 in the mobile 3 obtains the feedback instruction, the water distribution instruction for the downhole water distribution device at the current injection layer is sent to the second signal transceiver device 904 in the current downhole water distribution device through the first signal transceiver device 305. Then, after the second data storage and processing device 903 in the current downhole water distribution device obtains the water distribution instruction for the current injection layer through the second signal transceiver device 904, on the one hand, the current water distribution instruction is directly sent to the power device 906, at this time, the power device 906 adjusts the water distribution flow of the current injection layer according to the current water distribution instruction to complete the water distribution regulation task of the current injection layer; on the other hand, the second data storage and processing device 903 also transmits the dynamic production data (which has not been sent to the ground) for the current injection layer stored by itself to the first signal transceiver device 305 in the mobile 3 through the second signal transceiver device 904, and then the first data storage and processing device 304 in the mobile 3 obtains the dynamic production data (which needs to be transmitted to the ground) for the current injection layer through the first signal transceiver device 305 and stores the current dynamic production data, thereby completing the production data collection task of the current injection layer. In this way, the information exchange task of the water distribution instruction for the current injection layer carried by the mobile 3 and the production data collected by the downhole water distribution device is completed, so that the mobile 3 completes the production data collection task of the current injection layer, and the current downhole water distribution device completes the on-demand water distribution regulation according to the exchanged water distribution instruction for the current injection layer.

[0055] Thus, the intelligent signal traveler constructed by the application can exchange data with the signal transmission system in the downhole intelligent water distribution device, and meanwhile, the data reading, writing and storage function of the chip can be used to carry the downhole feedback production data to the wellhead for production data feedback transmission, so that the ground obtains the production parameter data including temperature, pressure, flow rate and the like obtained by downhole monitoring.

[0056] Further, the downhole water distribution device D in the embodiment of the application is used as a downhole intelligent water distribution device matched with the intelligent traveler C, which can not only monitor downhole production data, but also exchange data with the intelligent traveler C and adjust water distribution according to the received water distribution instructions.

[0057] Further, the water injection control system in the embodiment of the application further comprises an anti-overflow closing device 17. The anti-overflow closing device 17 is arranged at the bottom of the water injection pipe column 11. The anti-overflow closing device 17 is used to limit the position of the traveler 3 at the bottom of the well after the traveler 3 passes through all the downhole water distribution devices with the water flow.

[0058] As shown in Figure 2 , the anti-overflow closing device 17 is connected to the pipe column 11 and is constructed as a cylindrical structure. A through hole (not numbered) penetrating between the top and the bottom is arranged at the central axis position of the anti-overflow closing device 17, and the bottom of the anti-overflow closing device 17 has an anti-overflow screen. The upper and lower end faces of the through hole are horizontal and parallel to each other. The longitudinal edges of the axial section of the through hole are both in the shape of an open outward parabola. The minimum inner diameter of the through hole is slightly smaller than the outer diameter of the traveler 3, and the maximum inner diameter of the through hole is slightly larger than the outer diameter of the traveler 3. In actual application, when the traveler 3 passes through the last downhole water distribution device and enters the anti-overflow closing device, the fluid flow area will be smaller due to the significant reduction of the inner diameter (from the inner diameter of the wellbore 11 to the inner diameter of the through hole), and under the condition that the injection flow rate remains unchanged, the wellhead injection pressure will increase, and it can be known that the traveler 3 has reached the bottom of the wellbore 11.

[0059] In this way, the anti-overflow closing device 17 in the embodiment of the application can not only prevent the downward movement of the traveler 3 from moving out of the pipe column 11, but also can make the wellhead further prompt the traveler limiting device A to identify the time when the traveler 3 reaches the bottom of the wellbore 11 by sensing the sudden increase of the pressure when the traveler 3 is limited and stuck by the through hole, so as to immediately generate a stop water injection instruction, thereby realizing the linkage control of the water injection control system and the water injection device.

[0060] In addition, the dynamic pressure in the internal space of the device is monitored in real time in the son-limiting device A, and the timing of the arrival of the son 3 at the bottom of the wellbore is determined according to the monitored dynamic pressure. When it is detected that the son 3 has reached the bottom of the pipe string 11, a stop water injection instruction is generated to stop the water injection device (not shown) connected to the ground water delivery device B from injecting water. Specifically, the intelligent wellhead signal exchange device 1 in the son-limiting device A can monitor the internal dynamic pressure of the wellhead equipment 4 in real time. After the son 3 reaches the anti-overflow closure device 17 at the bottom of the wellbore 11, the wellhead pressure will change significantly, thereby detecting the timing of the arrival of the son at the bottom of the wellbore 11, and then generating a stop water injection instruction and sending the stop water injection instruction to the water injection device to stop the water injection device from delivering injection water to the ground water delivery device B. After the water injection device stops injecting water, the injection water flow rate in the water injection pipe string 11 gradually decreases and tends to be static. At this time, the son 3 moves from the bottom of the well to the wellhead in a static water environment relying on its own buoyancy, so that when the wellhead signal exchange device 1 detects that the son 3 gradually approaches the capture device 2, the capture device 2 is controlled to position and fix the son 3 at the wellhead. Finally, the wellhead signal exchange device 1 directly reads the dynamic production data of all downhole water distribution devices stored by the son 3. In this way, the son 3 completes a task of issuing a water distribution instruction and collecting production data.

[0061] Further, the son-limiting device A described in the embodiments of the present application is an intelligent wellhead that can be used in cooperation with the son C. The wellhead realizes the functions of capturing, fixing, releasing, signal exchanging and data reading of the son, ensures efficient transmission of intelligent son feedback data, and effectively improves work efficiency and reduces operating costs.

[0062] Again as Figure 2 shown, the ground water delivery device B described in the embodiments of the present application includes a first water injection pipeline (not numbered) and a second water injection pipeline (not numbered). The outlet of the first water injection pipeline communicates with the side wall of the wellhead equipment 4 in the son-limiting device A. The inlet of the first water injection pipeline serves as a water injection inlet for water injection operations and communicates with the water storage tank of the water injection device. The first end of the second water injection pipeline communicates with the side wall of the first water injection pipeline, and the second end of the second water injection pipeline communicates with the side wall of the wellhead equipment 4 in the son-limiting device A. The second end of the second water injection pipeline is located at the outlet of the first water injection pipeline. The first end of the second water injection pipeline is divided into two sections, a first pipeline inlet section and a first pipeline outlet section, by the communication of the first end of the second water injection pipeline with the side wall of the first water injection pipeline. Further, the second water injection pipeline serves as a bypass for the first pipeline outlet section and is connected in parallel with the first pipeline outlet section.

[0063] Specifically, the first injection water pipeline is used to communicate with the wellhead equipment 4 in the injection water operation mode and not to communicate with the side wall of the wellhead equipment in the water distribution operation mode. In addition, the second injection water pipeline is used to communicate with the wellhead equipment 4 in the water distribution operation mode. That is, in the normal injection water operation mode of the injection water regulating system, the injection water is transported to the wellhead through the first injection water pipeline to be injected into the well; in the water distribution operation mode of the injection water regulating system, the first pipeline inlet section is communicated with the second injection water pipeline, and the injection water is transported to the wellhead through the communicated first pipeline inlet section and the second injection water pipeline to be injected into the well.

[0064] Further, the ground water delivery device B described in the embodiment of the present application further comprises a first injection valve 5, a second injection valve 7 and a third injection valve 8 connected with the intelligent wellhead (the mobile son limit device A) respectively. The first injection valve 5 is arranged near the inlet of the first injection water pipeline, that is, arranged in the first pipeline inlet section. The second injection valve 7 is arranged in the second injection water pipeline. The third injection valve 8 is arranged near the outlet of the first injection water pipeline, that is, arranged in the first pipeline outlet section. In this way, the different opening and closing control of the injection valves 5, 7 and 8 by the mobile son limit device A makes the water in the injection water device delivered to the wellhead through different injection water delivery lines in different system operation modes, so as to assist the implementation of the injection water operation and the separate layer water distribution operation.

[0065] In addition, the ground water delivery device B described in the embodiment of the present application further comprises a flow meter 6 connected with the intelligent wellhead (the mobile son limit device A). The flow meter 6 is arranged in the first pipeline inlet section. Further, the mobile son limit device A described in the embodiment of the present application is further used to detect the dynamic flow of the inlet end of the ground water delivery device B in real time, so as to use the dynamic flow to control the flow rate of the injection water pumped into the ground water delivery device B (the first pipeline inlet section) by the injection water device, thereby dynamically adjusting the flow rate of the injection water and flexibly controlling the up and down movement of the mobile son 3 in the injection water string to the required water flow rate.

[0066] Figure 5 The figure is a schematic diagram of the operation process of the injection water regulating system for the injection water well in the embodiment of the present application. The following refers to the figure Figure 5 The operation states of the injection water regulating system described in the embodiment of the present application are described.

[0067] S1, in the normal injection water operation mode, the intelligent mobile son 3 is in the standby state, as shown in state 1 in the figure Figure 5 The injected water enters the injection water string 11 through the first injection valve 5, the flow meter 6, the third injection valve 8 and the wellhead equipment 4, and enters the target injection water formation after being distributed by the downhole intelligent water distribution device 1 and the downhole intelligent water distribution device 2;

[0068] S2, when the water injection and / or production data collection is needed, the intelligent mobile 3 is needed. The intelligent mobile 3 is wrapped by a pressure shell 301, and contains a power supply device 303, a data storage and processing system 304, and a signal transceiver device 305, filled with light insulation filling 302, the overall density of the mobile is less than water, and it can float in still water, and the size is slightly smaller than the water injection pipe, so it can move up and down in the water injection pipe. When the command is activated, the mobile limiting device sends an activation command through the intelligent wellhead antenna 1, and the intelligent wellhead mobile capturing device 2 releases the intelligent mobile 3. At this time, the injection valve three 8 is closed, and the injection valve two 7 is opened to change the water injection wellhead inlet. After the intelligent mobile 3 is released, it will be washed away from the wellhead by the water flow, and enter the water injection string 11, as shown in state 2 in Figure 5 After the intelligent mobile 3 is released, the signal transceiver device 305 will continuously send a weak signal to detect whether it is close enough to the downhole intelligent water distribution device one or two;

[0069] S3, the intelligent mobile 3 will move with the injected water through the downhole intelligent water distribution device one 9 and the downhole intelligent water distribution device two 10. The intelligent water distribution device 9 / 10 contains a power supply device 902, which can provide power for the data processing and storage system 903, the signal transceiver device 904, the production data monitoring system 905, and the control motor 906. Under normal water injection conditions, the production data monitoring system 905 will continuously monitor temperature, pressure, flow rate and other data, and store them in the processing and storage system 903. After the intelligent mobile 3 is released, it continuously sends a weak detection signal to determine whether it is close enough to the intelligent water distribution device. When it is close to the intelligent water distribution device, the signal transceiver device 904 in the intelligent water distribution device receives the signal sent by the intelligent mobile 3, processes the signal through the data processing and storage system 903, and then sends the feedback signal through the signal transceiver device 904. After receiving the feedback signal, the intelligent mobile 3 will start information exchange with the downhole intelligent water injection device 9 / 10. After the information exchange, the intelligent water distribution system will drive the control motor 906 to adjust the water injection outlet 908 according to the collected water distribution instructions, thereby completing the water distribution adjustment. After the information exchange, the intelligent mobile 3 will store the downhole production parameter data transmitted by the intelligent water distribution device 9 / 10.

[0070] S4, as the water injection continues, the intelligent mobile 3 will continue to move to the bottom of the tubing, and be blocked by the anti-overflow closing device 17 to prevent it from moving out of the tubing, as shown in state 3 in Figure 5 At this time, the tubing pressure at the wellhead will change, and the system can monitor and determine the time when the mobile 3 reaches the bottom of the string according to the pressure monitoring;

[0071] S5, after the intelligent mobile 3 moves to the bottom of the string, the water injection is paused, and the intelligent mobile 3 will float freely in the string 11 by virtue of the buoyancy, as shown in state 4 in Figure 5As shown in state 4 in the figure, until the wellhead equipment 4. The intelligent wellhead signal exchange system 1 will sense the approach of the intelligent mobile sonde 3, and command the intelligent wellhead mobile sonde capture device 2 to capture and fix the mobile sonde;

[0072] S6, the intelligent mobile sonde 3 performs data transmission with the intelligent wellhead signal exchange system 1, and the mobile sonde transmits the production parameter data carried by the mobile sonde to the intelligent wellhead signal exchange system 1 through the intelligent wellhead signal exchange system, and the intelligent wellhead signal exchange system 1 further transmits the collected production data to the ground computer for effective storage, and then empties the storage space in the mobile sonde 3, so as to enter the standby mode and wait for the next start. The injection control system described in the embodiment of the application completes a single operation.

[0073] Example One

[0074] Due to the change of formation pressure, it is necessary to perform downhole water distribution control once, reduce the water injection amount of the target layer 1 and increase the water injection amount of the target layer 2, and collect downhole pressure, temperature and flow data at the same time.

[0075] According to step 1, the system is started, the intelligent mobile sonde is activated, and the mobile sonde is given the required instruction information. The mobile sonde is released and continuously moves downward in the tubing under the action of water flow;

[0076] When the intelligent mobile sonde approaches the target layer 1, the intelligent mobile sonde performs instruction transmission and data exchange with the intelligent water distribution device corresponding to the target layer 1, and issues a command to reduce the water distribution valve to the water distributor. After the water distributor processes the signal, the water outlet is changed by mechanical action, and the temperature, pressure and flow data of the target layer 1 are transmitted to the mobile sonde;

[0077] After the intelligent mobile sonde receives and stores the data, it continues to move to the target layer 2, and performs instruction transmission and data exchange with the intelligent water distribution device corresponding to the target layer 2, and issues a command to increase the water distribution valve to the water distributor. After the water distributor processes the signal, the water outlet is changed by mechanical action, and the temperature, pressure and flow data of the target layer 2 are transmitted to the mobile sonde;

[0078] After the mobile sonde moves to the bottom of the tubing, it is sensed by the pressure system, and the water injection is stopped to make it float freely. As described in step 5, the mobile sonde moves to the wellhead and is fixed and data is released. This operation is completed, the target layer water distribution is successfully adjusted, and the temperature, pressure and flow data in a certain period of time in the downhole are collected.

[0079] On the other hand, based on the above-mentioned injection control system, the embodiment of the application further provides an injection control method for an injection well (hereinafter referred to as "injection control method"). Figure 6 The injection control method for an injection well of the embodiment of the application is shown in the figure. As shown in the figure, Figure 6As shown, the water injection control method according to the embodiment of the application is implemented according to the following steps:

[0080] Step S601, the ground water delivery device B is communicated with the mobile son limiting device A, and the mobile son limiting device A is used to inject water into the well;

[0081] Step S602, under the water distribution condition, the mobile son C receives a water distribution instruction used to control the water distribution of each downhole water distribution device;

[0082] Step S603, the mobile son limiting device A is used to release the mobile son C when the activation instruction is received, so that the mobile son C enters the water injection string along with the water flow after being released;

[0083] Step S604, each downhole water distribution device D arranged at the target layer and installed outside the sidewall of the water injection string is used to monitor the production data of the target layer, and when the mobile son C is detected, the current production data is exchanged with the water distribution instruction about itself carried by the mobile son C, so as to control the water distribution of the current layer section by using the exchanged water distribution instruction;

[0084] Step S605, the mobile son C floats to the wellhead after completing the data collection.

[0085] The application discloses a water injection control system and method for a water injection well. The application forms a special downhole data signal bidirectional transmission method, shortens the distance of data transmission and signal control, makes the data and instruction exchange transmission scene weakly interfered by the environment, and makes the data exchange speed faster and more stable, solves the problems that the existing wireless transmission measurement and control device is greatly interfered by environmental factors and has a limited use depth, and has practical significance for realizing efficient and low-cost intelligent oilfields.

[0086] The above merely describes the preferred embodiments of the application, but the protection scope of the application is not limited to this, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the application, which should be covered in the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection scope of the claims.

[0087] It should be understood that the disclosed embodiments of the application are not limited to the specific structures, processing steps or materials disclosed herein, but should extend to equivalent alternatives of these features understood by those skilled in the relevant art. It should also be understood that the terms used herein are for the purpose of describing specific embodiments only and are not meant to limit.

[0088] Reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. The appearances of the phrase "in one embodiment" or "an embodiment" in various places in the specification are not necessarily all referring to the same embodiment.

[0089] Although the present application has been described with reference to the above embodiments, the contents described are merely adopted embodiments for facilitating the understanding of the present application, and are not intended to limit the present application. Any modification and change in the form and details of the embodiments can be made by any person skilled in the art without departing from the spirit and scope of the present application, and the patent protection scope of the present application shall be subject to the scope defined by the appended claims.

Claims

1. A water injection regulation system for a water injection well, characterized in that The application comprises: a mobile-sub limiting device arranged at the wellhead, which is used to release the mobile-sub when receiving an activation instruction, and monitor the dynamic pressure of the internal space of the mobile-sub limiting device to determine the timing of the mobile-sub reaching the bottom of the wellbore, based on which a stop water injection instruction is generated to make the water injection device stop water injection and make the mobile-sub move from the well bottom to the wellhead in a static water environment relying on its own buoyancy; a ground water delivery device, the outlet of which is communicated with the internal space of the mobile-sub limiting device, which is used to inject water downhole through the mobile-sub limiting device; the mobile-sub, which is used to receive water distribution instructions for water distribution control of each downhole water distribution device in water distribution conditions, and enter the water injection string after being released with the water flow, and float to the wellhead after completing data collection, wherein the internal space of the pressure-bearing shell of the mobile-sub is filled with light insulation material, and the density of the constructed mobile-sub is less than water; a plurality of downhole water distribution devices, each of which is arranged at a target layer and installed outside the sidewall of the water injection string, which is used to monitor production data of the target layer, and exchange the production data with the water distribution instructions carried by the mobile-sub when detecting the mobile-sub approaching, to use the water distribution instructions for water distribution control.

2. The water injection regulation system of claim 1, wherein, The mobile-sub limiting device comprises: a wellhead device communicated with the outlet of the ground water delivery device, the bottom of which is communicated with the wellhead, which is used to provide a wellhead accommodation space for the mobile-sub; a capturing device arranged at the upper end of the wellhead device, which is used to control the location and release of the mobile-sub; a wellhead signal exchange device arranged outside the wellhead device and installed on the capturing device, which is used to facilitate the mobile-sub to obtain the water distribution instructions and read all the production data collected by the mobile-sub by communicating with the mobile-sub.

3. The water injection regulation system of claim 2, wherein, The wellhead signal exchange device also communicates with the capturing device, which is used to send the activation instruction to the capturing device in water distribution conditions, and real-time detect whether the mobile-sub approaches the capturing device, and generate a capturing instruction when detecting the mobile-sub, so as to send the capturing instruction to the capturing device.

4. The injection water regulation system of any one of claims 1-3, wherein, The mobile-sub comprises: a pressure-bearing shell; a first signal transceiver device arranged inside the pressure-bearing shell, which is used to continuously emit a first detection signal; a first data storage and processing device arranged inside the pressure-bearing shell, which is connected with the first signal transceiver device, and is used to communicate with the current downhole water distribution device to realize information exchange of water distribution instructions and production data when approaching the underwater water distribution device of the corresponding target water distribution layer under the cooperation of the first signal transceiver device; a light insulation filling part arranged inside the pressure-bearing shell.

5. The water injection regulation system of claim 4, wherein, The downhole water distribution device comprises: a water distribution nipple body arranged on the sidewall of the water injection string, the two ends of the water distribution nipple body are provided with upper and lower interfaces; a water injection outlet communicated with the water injection string, which is arranged on the sidewall of the water distribution nipple body; a second signal transceiver device; a second data storage and processing device connected with the second signal transceiver device, for wireless communication with the traveler when the first probe signal is detected, so as to realize information exchange of water distribution instructions and production data; a power device connected with the water injection outlet and the second data storage and processing device, for regulating the flow rate and / or outlet diameter of the water injection outlet under the control of the water distribution instructions.

6. The injection water regulation system of any one of claims 1-3, wherein, The water injection regulation system further comprises an anti-overflow collection device arranged at the bottom of the wellbore, which is used for limiting the position of the bottom of the well after the traveler passes through all the downhole water distribution devices with water flow.

7. The water injection regulation system of any one of claims 1-3, wherein, The ground water delivery device comprises: a first water injection pipeline, the outlet of which is in communication with the sidewall of the wellhead equipment in the traveler limiting device, for communication with the wellhead equipment in the water injection mode and not in communication with the sidewall of the wellhead equipment in the water distribution mode; a second water injection pipeline, the first end of which is in communication with the sidewall of the first water injection pipeline, and the second end of which is in communication with the sidewall of the wellhead equipment in the traveler limiting device, for communication with the wellhead equipment in the water distribution mode.

8. The water injection regulation system of claim 7, wherein, The ground water delivery device further comprises: a first injection valve near the inlet of the first water injection pipeline; a second injection valve arranged in the second water injection pipeline; a third injection valve near the outlet of the first water injection pipeline.

9. A water injection regulation method for a water injection well, characterized by, The water injection regulation method is implemented by using the water injection regulation system according to any one of claims 1-8, wherein the water injection regulation method comprises: communicating the ground water delivery device with the traveler limiting device, and injecting water into the well through the traveler limiting device; in the water distribution mode, the traveler receives water distribution instructions for regulating the water distribution of each downhole water distribution device; using the traveler limiting device to release the traveler when an activation instruction is received, so that the traveler enters the water injection string with water flow after being released; using each downhole water distribution device arranged at the target layer and installed outside the sidewall of the water injection string to monitor the production data of the target layer, and exchanging the production data with the water distribution instructions about itself carried by the traveler when the traveler is detected, so as to regulate the water distribution by using the water distribution instructions; the traveler floats to the wellhead after completing data collection.

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