A system and method for communicating in a zonal injection system

Abstract

The embodiment of the present application provides an oilfield layered water injection system and a communication method, at least two packers are arranged in a casing, the at least two packers divide a region between the casing and a tubing into at least two well layers. A first metal centralizer is arranged below a water distributor of a bottommost well layer, a second metal centralizer is arranged above a water distributor of a topmost well layer, an auxiliary water distributor is used to send an electromagnetic wave signal to a relay water distributor when a signal needs to be transmitted to the ground. The relay water distributor changes a water injection mode of the tubing to the casing of the well layer according to the signal transmitted by the auxiliary water distributor. A control module determines the signal transmitted by the relay water distributor according to a change signal of water pressure and flow. The embodiment of the present application realizes wireless uploading of all signals of the auxiliary water distributor in the well through the relay water distributor, avoids the problem that a wellhead pressure wave change amplitude is small and difficult to identify due to different reservoir water absorption characteristics, and improves communication adaptability and communication efficiency.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of oilfield stratified water injection, and particularly to an oilfield stratified water injection system and communication method. Background Technology

[0002] Petroleum is an indispensable strategic resource for national survival and development. Waterflooding is the main development method for oilfields in my country, with 80% of domestic production coming from waterflooding. The effectiveness of waterflooding directly affects national energy security. Domestic oilfields generally have multi-layered and heterogeneous characteristics. Indiscriminate waterflooding can lead to single-layer surges. Therefore, the widespread adoption of stratified waterflooding is a key and effective means to improve waterflood recovery rates.

[0003] Layered water injection systems typically require bidirectional communication between the wellhead communication controller and the water distributors at each layer downhole. Existing layered injection systems suffer from low communication efficiency and poor reliability. Summary of the Invention

[0004] This invention provides an oilfield stratified water injection system and communication method. The system enables wireless transmission of all signals from the downhole auxiliary water distributor through a relay water distributor, and also enables wireless communication between the relay water distributor and the surface. This avoids the problem of difficulty in identifying the small changes in wellhead pressure waves caused by different reservoir water absorption characteristics, thus improving the efficiency of wireless communication and enhancing its adaptability and reliability for multi-layer stratified water injection.

[0005] In a first aspect, embodiments of the present invention provide an oilfield stratified water injection system, comprising: casing;

[0006] Oil tubing installed inside the casing;

[0007] At least two isolation layers are provided inside the casing and between the casing and the tubing, and the at least two isolation layers divide the area between the casing and the tubing into at least two well layers;

[0008] At least two water distributors are provided, with one water distributor for each well layer; the at least two water distributors include a relay water distributor and an auxiliary water distributor.

[0009] The first metal stabilizer and the second metal stabilizer are located below the water distributor of the bottom layer of the well and above the water distributor of the top layer of the well. Both the first metal stabilizer and the second metal stabilizer are in contact with the casing and the tubing.

[0010] The control module is located on the ground.

[0011] The auxiliary water distributor is used to send electromagnetic wave signals to the relay water distributor when it is necessary to transmit signals to the ground;

[0012] The relay water distributor is used to receive electromagnetic wave signals, determine the signal transmitted by the auxiliary water distributor based on the electromagnetic wave signals, and change the water injection method from the tubing to the casing in its well layer according to the signal transmitted by the auxiliary water distributor, so that the water in the tubing in its well layer is injected into the casing in a first preset manner.

[0013] The control module is used to detect changes in water pressure and flow rate in the oil pipe, and to determine the signal transmitted by the relay water distributor based on the changes in water pressure and flow rate.

[0014] Optionally, the medium absorption characteristics are best on the outside of the casing of the well layer where the relay water distributor is located.

[0015] Optionally, the control module is also used to change the water injection method of the ground to the oil pipe when it is necessary to transmit a signal to the water distributor, so that the ground injects water into the oil pipe in a second preset manner;

[0016] Each water distributor is used to detect changes in water pressure and flow rate in the oil pipe, and determines the signal transmitted by the control module based on the water pressure and flow rate.

[0017] Optionally, each water distributor includes a control circuit, a battery pack, an electromagnetic signal generator, a first pressure flow meter, and a valve;

[0018] The control circuit is electrically connected to the battery pack, electromagnetic signal generator, first pressure flow meter, and valve, respectively.

[0019] The battery pack powers the control circuitry, the first pressure flow meter, the electromagnetic signal generator, and the valves.

[0020] The first pressure flow meter is used to detect the water pressure and flow rate in the oil pipe;

[0021] The control circuit is used to acquire the water pressure and flow rate measured by the first pressure flow meter, determine the signal transmitted by the control module based on the water pressure and flow rate, and change the valve opening degree based on the signal transmitted by the control module.

[0022] Optionally, the relay water distributor may also include an electromagnetic signal receiver;

[0023] An electromagnetic signal receiver is used to receive electromagnetic wave signals;

[0024] The control circuit of the relay water distributor is also used to acquire the electromagnetic wave signal received by the electromagnetic signal receiver, and determine the signal transmitted by the auxiliary relay based on the electromagnetic wave signal.

[0025] Optionally, the control circuitry includes a generator;

[0026] The generator is used to output pulse signals to the valve to adjust the valve opening.

[0027] Optionally, the control module includes a main control circuit, a main valve, and a second pressure and flow meter;

[0028] The main control circuit is used to change the opening of the main valve according to the signal to be transmitted when it is necessary to transmit a signal to the water distributor, so that the main valve injects water into the oil pipe in a second preset manner.

[0029] The second pressure flow meter is used to detect the water pressure and flow rate in the oil pipe;

[0030] The main control circuit is also used to acquire the water pressure and flow rate measured by the second pressure flow meter, and to determine the received signal based on the water pressure and flow rate.

[0031] Secondly, embodiments of the present invention provide a communication method for an oilfield stratified water injection system, executed by an oilfield stratified system provided in any embodiment of the present invention, including:

[0032] When the auxiliary water distributor needs to transmit signals to the ground, it sends electromagnetic wave signals to the relay water distributor.

[0033] The relay water distributor receives electromagnetic wave signals, determines the signal transmitted by the auxiliary water distributor based on the electromagnetic wave signals, and changes the water injection method from the tubing to the casing in its well layer according to the signal transmitted by the auxiliary water distributor, so that the water in the tubing in its well layer is injected into the casing in a first preset manner.

[0034] The control module detects changes in water pressure and flow rate in the oil pipe and determines the signal transmitted by the relay water distributor based on these changes.

[0035] Optionally, the communication method of the oilfield stratified water injection system also includes: when the control module needs to transmit a signal to the water distributor, changing the water injection method from the ground to the oil pipe, so that the control ground injects water into the oil pipe in a second preset manner;

[0036] Each water distributor detects changes in water pressure and flow rate in the oil pipe, and determines the signal transmitted by the control module based on the water pressure and flow rate.

[0037] Optionally, the medium absorption characteristics are best on the outside of the casing of the well layer where the relay water distributor is located.

[0038] In the technical solution provided by this invention embodiment, when the auxiliary water distributor transmits a signal to the ground, it sends an electromagnetic wave signal to the relay water distributor. The relay water distributor receives the electromagnetic wave signal, determines the signal transmitted by the auxiliary water distributor based on the electromagnetic wave signal, and changes the water injection method from the tubing to the casing in its well layer according to the signal transmitted by the auxiliary water distributor, so that water in the tubing of its well layer is injected into the casing in a first preset manner. The control module detects changes in water pressure and flow rate in the tubing and determines the signal transmitted by the relay water distributor based on the changes in water pressure and flow rate. In this invention embodiment, short-range communication between the auxiliary water distributor and the relay water distributor is achieved by sending electromagnetic waves, while long-range communication between the relay water distributor and the control module is achieved by pressure pulses. Because the distance between water distributors is short, the auxiliary water distributor transmits signals to the relay water distributor with high accuracy and efficiency. The relay water distributor can be selected from well layers with relatively stable signal transmission. Transmitting signals to the surface through the relay water distributor avoids the problem of difficulty in identifying wellhead pressure wave variations due to small amplitudes caused by different reservoir water absorption characteristics, thus improving adaptability and communication efficiency. Through this method, wireless communication can be achieved for 4-6 stratified injection wells.

[0039] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of a wavecode wireless layered water injection system.

[0042] Figure 2 This is a schematic diagram of the structure of an oilfield stratified water injection system provided in an embodiment of the present invention;

[0043] Figure 3 This is a schematic diagram of the structure of an auxiliary water distributor provided in an embodiment of the present invention;

[0044] Figure 4 This is a schematic diagram of the structure of a relay water distributor provided in an embodiment of the present invention;

[0045] Figure 5 This is a schematic diagram of the structure of a control module provided in an embodiment of the present invention;

[0046] Figure 6 This is a flowchart of a communication method for a layered water injection system in an oilfield, provided by an embodiment of the present invention.

[0047] Figure 7 This is a flowchart of another communication method for an oilfield stratified water injection system provided in an embodiment of the present invention;

[0048] Figure 8 This is a flowchart of a top-down communication method for a layered water injection system in an oilfield, provided by an embodiment of the present invention.

[0049] Figure 9 This is a flowchart of a bottom-up communication method for a layered water injection system in an oilfield, provided by an embodiment of the present invention. Detailed Implementation

[0050] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0051] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0052] Figure 1 This is a schematic diagram of a wavecode wireless stratified water injection system. Currently, there are two main technical routes for stratified water injection: one is the cable-controlled route, where downhole parameters are transmitted to the surface via a pre-installed cable outside the tubing; the other is the wavecode wireless route, where downhole parameters are transmitted to the surface wirelessly. Figure 1The working principle of wavecode-based wireless technology is as follows: Assuming a water injection well has n layers, when data from any layer (let's say the second layer) needs to be transmitted, the second layer's water distributor's electrically controlled valve actively switches on and off, causing a change in tubing pressure. The wellhead communication controller receives the pressure wave change signal and decodes it to obtain the downhole data. The two-way wireless communication between each layer and the wellhead is affected by the characteristics of the current formation and other formations. However, due to the different water absorption characteristics of the current formation and other formations (for example, rock layers have weak water absorption), different pressure changes will occur during communication. For some layers, due to the influence of the water absorption characteristics of other layers (e.g., strong water absorption), the wellhead pressure wave change amplitude may be small and difficult to identify, affecting communication reliability; or the pressure wave change time may be long, resulting in low communication efficiency, with an average transmission time of 2.5 hours for a single data set. Using cables for communication is prone to loosening at cable connectors, leading to poor reliability.

[0053] Figure 2 This is a schematic diagram of the structure of an oilfield stratified water injection system provided in an embodiment of the present invention. See also... Figure 2 An oilfield stratified water injection system includes: a casing 1, tubing 2 installed within the casing, at least two sealing layers, each sealing layer being installed within the casing 1 and between the casing 1 and the tubing 2, dividing the area between the casing 1 and the tubing 2 into at least two well layers. At least two water distributors, one for each well layer; the at least two water distributors include a relay water distributor P1 and an auxiliary water distributor. A first metal centralizer 5 and a second metal centralizer 4, the first metal centralizer 5 being located below the water distributor of the lowest well layer, and the second metal centralizer 4 being located above the water distributor of the highest well layer, both contacting the casing 1 and the tubing 2. A control module 3, located on the surface. The auxiliary water distributor is used to send electromagnetic wave signals to the relay water distributor P1 when signals need to be transmitted to the surface. The relay water distributor P1 receives electromagnetic wave signals, determines the signal transmitted by the auxiliary water distributor based on the electromagnetic wave signals, and changes the water injection method from the tubing 2 to the casing 1 in its well layer according to the signal transmitted by the auxiliary water distributor, so that water in the tubing 2 in its well layer is injected into the casing 1 in a first preset manner. The control module 3 detects changes in water pressure and flow rate in the tubing 2, and determines the signal transmitted by the relay water distributor P1 based on the changes in water pressure and flow rate.

[0054] Among them, combined Figure 2The sealing layers installed inside casing 1 include: sealing layer 1, sealing layer 2...sealing layer n. Auxiliary water distributors include: auxiliary water distributor P2, auxiliary water distributor P3...auxiliary water distributor Pn. Control module 3 may include a communication controller. The distance between each layer of water distributors is relatively short (within 100 meters). The distance between relay water distributor P1 and the ground is relatively long (possibly reaching several kilometers, or even further). The first metal centralizer 5 and the second centralizer 4 are used to short-circuit the tubing 2 and casing 1, so that the magnetic field generates current in the first metal centralizer 5 and the second metal centralizer 4. The first preset mode is that the relay water distributor P1 controls the injection of water from the tubing 2 in its well layer into casing 1 based on the detected electromagnetic wave signal; for example, it could be a mode that controls the opening and closing of the valve for injecting water into casing 1. The relay water distributor P1 can be selected from the water distributors with the most stable signal transmission to the control module 3 on the ground.

[0055] Specifically, when the auxiliary water distributor transmits a signal to the ground, it sends an electromagnetic wave signal. The magnetic field generates a current within the range of the first metal centralizer 5 and the second metal centralizer 4. The current is transmitted along the tubing 2 to the relay water distributor P1. After receiving the electromagnetic wave signal transmitted by the auxiliary water distributor, the relay water distributor P1 determines the signal transmitted by the auxiliary water distributor based on the received electromagnetic wave signal. Based on the signal transmitted by the auxiliary water distributor, it increases the water pressure and flow rate of the tubing 2 in the well layer to the casing 1, so that the water pressure and flow rate in the tubing 2 change. The control module 3 detects the change in water pressure and flow rate in the tubing 1 and determines the signal transmitted by the relay water distributor P1 based on the detected change signal in the water pressure and flow rate in the tubing 2.

[0056] In the technical solution provided by this embodiment of the invention, when the auxiliary water distributor transmits a signal to the ground, it sends an electromagnetic wave signal to the relay water distributor P1. The relay water distributor P1 receives the electromagnetic wave signal, determines the signal transmitted by the auxiliary water distributor based on the electromagnetic wave signal, and changes the water injection method from the tubing 2 to the casing 1 in its well layer according to the signal transmitted by the auxiliary water distributor, so that the water in the tubing 2 in its well layer is injected into the casing 1 in a first preset manner. The control module 3 detects the changes in water pressure and flow rate in the tubing 2, and determines the signal transmitted by the relay water distributor P1 based on the changes in water pressure and flow rate. In this embodiment of the invention, short-distance communication between the auxiliary water distributor and the relay water distributor P1 is achieved by sending electromagnetic waves, while long-distance communication between the relay water distributor P1 and the control module 3 is achieved by pressure pulses. Because the distance between the water distributors is short, the auxiliary water distributor transmits signals to the relay water distributor P1 with high accuracy and efficiency. The relay water distributor P1 can be selected from well layers with relatively stable signal transmission. Transmitting signals to the surface through the relay water distributor P1 avoids the problem of difficulty in identifying wellhead pressure wave variations due to small amplitudes caused by different reservoir water absorption characteristics, thus improving adaptability and communication efficiency. Through this method, wireless communication between 4-6 stratified injection wells can be achieved.

[0057] See also Figure 2 Based on the above embodiments, optionally, the medium absorption characteristics on the outside of the casing 1 of the well layer where the relay water distributor P1 is located are the best.

[0058] In this embodiment, the layer with the best medium water absorption characteristics on the outside of the sleeve 1 is designated as the main communication layer, and the water distributor of the main communication layer is the relay water distributor P1. The main communication layer may be the first layer or the second layer; this is not a limitation in the comparison of embodiments of the present invention.

[0059] Specifically, when water is injected into casing 1, the formation with the best water absorption capacity absorbs more water, resulting in significant changes in water pressure and flow rate in tubing 2. This leads to large and rapid fluctuations in the wellhead pressure wave. Using the best water absorption capacity layer as the main communication layer for long-distance wireless communication with the surface ensures good signal transmission efficiency and stability. This avoids the problem of difficulty in identifying wellhead pressure wave fluctuations due to small fluctuations caused by different reservoir water absorption characteristics, thus improving the efficiency of wireless communication.

[0060] See also Figure 2 Based on the above embodiments, optionally, the control module 3 is also used to change the water injection method of the ground into the oil pipe 2 when it is necessary to transmit a signal to the water distributor, so that the ground injects water into the oil pipe 2 in a second preset manner. Each water distributor is used to detect changes in water pressure and flow rate in the oil pipe 2, and determines the signal transmitted by the control module 3 based on the water pressure and flow rate.

[0061] The second preset method is the method of injecting water into the casing 1 from the oil pipe 2, which is determined by the signal transmitted to the water distributor as needed. The water distributor includes a relay water distributor P1, an auxiliary water distributor P2, an auxiliary water distributor P3, etc.

[0062] Specifically, when the ground transmits signals to the water distributors at each level, the control module 3 controls the ground to inject water into the oil pipe 2, so that the water pressure and flow rate in the oil pipe 2 change. Each water distributor detects the water pressure and flow rate in the oil pipe 1 of its respective well layer, and decodes the detected water pressure and flow rate signals in the oil pipe 1 to obtain the signal transmitted by the control module 3.

[0063] See also Figure 2 Based on the above embodiments, and exemplarily, according to existing water absorption characteristic curves, the main communication layer is determined. Taking the first well layer as the main communication layer (the water distributor of the first well layer is the relay water distributor) as an example, the relationship between each layer's water distributor and the first layer is determined. When transmitting signals from top to bottom, ground data is broadcast to each layer's water distributor without the need for relays. When communicating wirelessly from bottom to top, each layer's auxiliary water distributor transmits to the main communication layer (i.e., relay water distributor P1) by emitting electromagnetic waves. The main communication layer then wirelessly uploads the signal to the ground via pressure pulses. Specifically, auxiliary water distributor P2 generates current within the range of the first metal centralizer 5 and the second metal centralizer 4 by emitting electromagnetic wave signals. Relay water distributor P1 identifies the change in electromagnetic signal and obtains the signal transmitted by auxiliary water distributor P2. Auxiliary water distributor P3 generates current within the range of the first metal centralizer 5 and the second metal centralizer 4 by emitting electromagnetic wave signals. Relay water distributor P1 identifies the change in electromagnetic signal and obtains the signal transmitted by auxiliary water distributor P3. Similarly, the auxiliary water distributor Pn generates current within the range of the first metal centralizer 5 and the second metal centralizer 4 by emitting electromagnetic wave signals. The relay water distributor P1 identifies the changes in electromagnetic signals and obtains the signals transmitted by the auxiliary water distributor Pn. Then, the relay water distributor P1 realizes the wireless and efficient uploading of data from each layer of water distributors in the well through high-efficiency pressure pulses, where n is the number of auxiliary water distributors, and n is greater than or equal to 2.

[0064] Figure 3 This is a schematic diagram of an auxiliary water distributor provided in an embodiment of the present invention. See also... Figure 2 and Figure 3Based on the above embodiments, optionally, each water distributor includes a control circuit 6, a battery pack 8, an electromagnetic signal generator 9, a first pressure flow meter 7, and a valve 10. The control circuit 6 is electrically connected to the battery pack 8, the electromagnetic signal generator 9, the first pressure flow meter 7, and the valve 10. The battery pack 8 supplies power to the control circuit 6, the first pressure flow meter 7, the electromagnetic signal generator 9, and the valve 10. The first pressure flow meter 7 is used to detect the water pressure and flow rate in the oil pipe 2. The control circuit 6 acquires the water pressure and flow rate measured by the first pressure flow meter 7, determines the signal transmitted by the control module 3 based on the water pressure and flow rate, and changes the opening degree of the valve 10 according to the signal transmitted by the control module 3.

[0065] Specifically, when the auxiliary water distributor transmits a signal to the ground, its electromagnetic signal generator 7 sends an electromagnetic wave signal, generating a current within the range of the first metal stabilizer 5 and the second metal stabilizer 4. This current travels upwards along the intermediate oil pipe 2. After receiving the electromagnetic wave signal from the auxiliary water distributor, the relay water distributor P1's control circuit 6 determines the signal transmitted by the auxiliary water distributor based on the received signal. It then adjusts the opening of its valve 10 according to the signal to increase the water pressure and flow rate injected into the casing 1 from the oil pipe 2. The relay water distributor P1's first pressure flow meter 7 detects the water pressure and flow rate in the oil pipe 2. After obtaining the signal from the first pressure flow meter 7, the relay water distributor P1's control circuit determines the signal transmitted by the auxiliary water distributor and transmits it to the control module 3. When the control module 3 transmits a signal to the ground, the control module 3 increases the water pressure and flow rate of the water injected into the oil pipe 2 from the ground. The first pressure flow meter 7 of each water distributor detects the change signals of water pressure and flow rate in the oil pipe 2. After the control circuit 6 of each water distributor obtains the change signals detected by its respective first pressure flow meter 7, it determines the signal transmitted by the control module 3 based on the obtained change signals of water pressure and flow rate, and adjusts the opening degree of its respective valve 10 according to the signal transmitted by the control module 3.

[0066] Figure 4 This is a schematic diagram of a relay water distributor provided in an embodiment of the present invention. See also... Figure 2 and Figure 4 Optionally, based on the above embodiments, the relay water distributor P1 further includes an electromagnetic signal receiver 11. The electromagnetic signal receiver 11 is used to receive electromagnetic wave signals. The control circuit 6 of the relay water distributor P1 is also used to acquire the electromagnetic wave signals received by the electromagnetic signal receiver 11 and determine the signal transmitted by the auxiliary relay based on the electromagnetic wave signals.

[0067] Specifically, when the auxiliary water distributor sends an electromagnetic wave signal to the relay water distributor P1, the electromagnetic signal receiver 11 of the relay water distributor P1 receives the electromagnetic wave signal. After the control circuit 6 of the relay water distributor P1 obtains the electromagnetic wave signal received by the electromagnetic signal receiver 11, it determines the signal transmitted by the auxiliary water distributor based on the obtained electromagnetic wave signal.

[0068] See Figure 3 and Figure 4 Based on the above embodiments, optionally, the control circuit 6 includes a generator 61. The generator 61 is used to output pulse signals to the valve 10 to adjust the opening degree of the valve 10.

[0069] The generator 61 can be understood as a type of valve.

[0070] Specifically, when the control module 3 transmits a signal to each water distributor to control the water distributor to increase or stop increasing water supply, the generator 61 of each water distributor receives the signal transmitted by the control module 3 and outputs a pulse signal to its respective valve 10 to adjust the opening degree of its respective valve 10.

[0071] Figure 5 This is a schematic diagram of the structure of a control module provided in an embodiment of the present invention. See also: Figure 2 and Figure 5 Based on the above embodiments, optionally, the control module includes a main control circuit 12, a main valve 14, and a second pressure and flow meter 13. The main control circuit 12 is used to change the opening degree of the main valve 14 according to the signal to be transmitted to the water distributor, so that the main valve 14 injects water into the oil pipe 2 in a second preset manner. The second pressure and flow meter 13 is used to detect the water pressure and flow rate in the oil pipe 2. The main control circuit 12 is also used to acquire the water pressure and flow rate measured by the second pressure and flow meter 13, and determine the received signal based on the water pressure and flow rate.

[0072] Specifically, when control module 3 transmits signals to the water distributors on each floor, main control circuit 12 increases the opening of main valve 14, so that water is injected into oil pipe 2 from the ground in a second preset manner, thereby changing the water pressure and flow rate in oil pipe 2. Relay water distributor P1 and auxiliary water distributor detect the changes in water pressure and flow rate in oil pipe 2, and can determine the signal transmitted by control module 3. When auxiliary water distributor transmits signals to the ground, it sends an electromagnetic wave signal to relay water distributor P1. After receiving the electromagnetic wave signal, relay water distributor P1 increases the opening of its valve to increase the water pressure and flow rate of water injected into casing 1 from oil pipe 2. The second pressure and flow meter 13 in control module 3 detects the changes in water pressure and flow rate in oil pipe 2. After obtaining the changes in water pressure and flow rate detected by the second pressure and flow meter 13 in oil pipe 2, main control circuit 12 determines the signal transmitted by relay water distributor P1 based on the changes in water pressure and flow rate.

[0073] This invention also provides a communication method for an oilfield stratified water injection system. Figure 6 This is a flowchart of a communication method for an oilfield stratified water injection system provided in an embodiment of the present invention. See also... Figure 6 The communication method for the oilfield stratified water injection system is executed by the oilfield stratified system provided in any embodiment of the present invention, including:

[0074] S110, when the auxiliary water distributor needs to transmit signals to the ground, sends electromagnetic wave signals to the relay water distributor.

[0075] S120, the relay water distributor receives electromagnetic wave signals, determines the signal transmitted by the auxiliary water distributor based on the electromagnetic wave signals, and changes the water injection method from the tubing to the casing in its well layer according to the signal transmitted by the auxiliary water distributor, so that the water in the tubing in its well layer is injected into the casing in a first preset manner.

[0076] S130: The control module detects changes in water pressure and flow rate in the oil pipe and determines the signal transmitted by the relay water distributor based on these changes.

[0077] In the technical solution provided by this invention embodiment, when the auxiliary water distributor transmits a signal to the ground, it sends an electromagnetic wave signal to the relay water distributor. The relay water distributor receives the electromagnetic wave signal, determines the signal transmitted by the auxiliary water distributor based on the electromagnetic wave signal, and changes the water injection method from the tubing to the casing in its well layer according to the signal transmitted by the auxiliary water distributor, so that water in the tubing of its well layer is injected into the casing in a first preset manner. The control module detects changes in water pressure and flow rate in the tubing and determines the signal transmitted by the relay water distributor based on the changes in water pressure and flow rate. In this invention embodiment, short-range communication between the auxiliary water distributor and the relay water distributor is achieved by sending electromagnetic waves, while long-range communication between the relay water distributor and the control module is achieved by pressure pulses. Because the distance between water distributors is shorter than the distance between the relay water distributor and the ground, the auxiliary water distributor transmits signals to the relay water distributor with high accuracy and efficiency. The relay water distributor can be selected from well layers with relatively stable signal transmission. Transmitting signals to the ground through the relay water distributor avoids the problem of difficulty in identifying wellhead pressure wave variations due to different reservoir water absorption characteristics, thus improving adaptability and communication efficiency. Through this method, wireless communication between 4-6 stratified injection wells can be achieved.

[0078] Based on the above embodiments, optionally, the medium absorption characteristics on the outside of the casing of the well layer where the relay water distributor is located are the best.

[0079] Figure 7 This is a flowchart of another communication method for an oilfield stratified water injection system provided in an embodiment of the present invention. See also... Figure 7Based on the above embodiments, optionally, the communication method for oilfield stratified water injection systems also includes:

[0080] S140. When the control module needs to transmit a signal to the water distributor, it changes the water injection method from the ground to the oil pipe, so that the ground injects water into the oil pipe in a second preset manner.

[0081] S150: Each water distributor detects changes in water pressure and flow rate in the oil pipe, and determines the signal transmitted by the control module based on the changes in water pressure and flow rate.

[0082] The communication method of the oilfield stratified water injection system in this embodiment of the invention belongs to the same inventive concept as the oilfield stratified water injection system provided in any embodiment of the invention, and has corresponding beneficial effects. For technical details not detailed in this embodiment, please refer to the oilfield stratified water injection system provided in any embodiment of the invention.

[0083] Figure 8 This is a flowchart of a top-down communication method for a layered water injection system in an oilfield, provided by an embodiment of the present invention. (See also...) Figure 8 For example, the top-down communication method is as follows: the ground control command is transmitted to the control module, the control module encodes the control command signal and adjusts the opening of the main valve according to the encoded signal to increase the ground water injection into the oil pipe. The water pressure and flow rate change signals of the oil pipe are transmitted to the water distributors of each layer. After receiving the water pressure and flow rate change signals of the oil pipe, each water distributor decodes them and adjusts the opening of its valve according to the decoded signal.

[0084] Figure 9 This is a flowchart of a bottom-up communication method for a layered water injection system in an oilfield, provided by an embodiment of the present invention. (See also...) Figure 9 For example, the bottom-up communication method is as follows: the auxiliary water distributor transmits water pressure and flow data to the relay water distributor in the main communication layer via electromagnetic wave signals. After receiving the electromagnetic wave signals, the relay water distributor determines the signal transmitted by the auxiliary water distributor and adjusts its valve opening according to the signal transmitted by the auxiliary water distributor to change the water pressure and flow in the oil pipe. The control module detects the changes in water pressure and flow and determines the signal transmitted by the relay water distributor.

[0085] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0086] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A layered water injection system for oilfields, characterized in that, include: casing; Oil tubing installed inside the casing; At least two sealing layers are disposed within the casing and between the casing and the tubing, the at least two sealing layers dividing the area between the casing and the tubing into at least two well layers; At least two water distributors are provided, with one water distributor corresponding to each well layer; the at least two water distributors include a relay water distributor and an auxiliary water distributor; wherein, the layer with the best medium water absorption characteristics outside the casing is taken as the main communication layer, the water distributor of the main communication layer is a relay water distributor, and the water distributors corresponding to other well layers are auxiliary water distributors. A first metal stabilizer and a second metal stabilizer, wherein the first metal stabilizer is located below the water distributor of the bottom layer of the well, and the second metal stabilizer is located above the water distributor of the top layer of the well. Both the first metal stabilizer and the second metal stabilizer are in contact with the casing and the tubing. Control module, the control module is installed on the ground; The auxiliary water distributor is used to send electromagnetic wave signals to the relay water distributor when it is necessary to transmit signals to the ground. The relay water distributor is used to receive electromagnetic wave signals, determine the signal transmitted by the auxiliary water distributor based on the electromagnetic wave signals, and change the water injection method from the tubing of the well where the relay water distributor is located to the casing based on the signal transmitted by the auxiliary water distributor, so that water in the tubing of the well where the relay water distributor is located is injected into the casing in a first preset manner; the control module is used to detect changes in water pressure and flow rate in the tubing, and determine the signal transmitted by the relay water distributor based on the changes in water pressure and flow rate.

2. The system according to claim 1, characterized in that: The control module is also used to change the water injection method of the ground to the oil pipe when it is necessary to transmit a signal to the water distributor, so that the ground injects water into the oil pipe in a second preset manner; Each of the aforementioned water distributors is used to detect changes in water pressure and flow rate in the oil pipe, and to determine the signal transmitted by the control module based on the water pressure and flow rate.

3. The system according to claim 2, characterized in that: Each of the aforementioned water distributors includes a control circuit, a battery pack, an electromagnetic signal generator, a first pressure flow meter, and a valve; The control circuit is electrically connected to the battery pack, the electromagnetic signal generator, the first pressure flow meter, and the valve, respectively. The battery pack is used to power the control circuit, the first pressure flow meter, the electromagnetic signal generator, and the valve; The first pressure flow meter is used to detect the water pressure and water flow rate in the oil pipe; The control circuit is used to acquire the water pressure and flow rate measured by the first pressure flow meter, determine the signal transmitted by the control module based on the water pressure and flow rate, and change the valve opening degree based on the signal transmitted by the control module.

4. The system according to claim 3, characterized in that: The relay water distributor also includes an electromagnetic signal receiver; The electromagnetic signal receiver is used to receive electromagnetic wave signals; The control circuit of the relay water distributor is also used to acquire the electromagnetic wave signal received by the electromagnetic signal receiver, and determine the signal transmitted by the auxiliary relay based on the electromagnetic wave signal.

5. The system according to claim 3, characterized in that: The control circuit includes a generator; The generator is used to output pulse signals to the valve to adjust the valve opening.

6. The system according to claim 2, characterized in that: The control module includes a main control circuit, a main valve, and a second pressure and flow meter; The main control circuit is used to change the opening of the main valve according to the signal to be transmitted when it is necessary to transmit a signal to the water distributor, so that the main valve injects water into the oil pipe in a second preset manner; The second pressure flow meter is used to detect the water pressure and water flow rate in the oil pipe; The main control circuit is also used to acquire the water pressure and flow rate measured by the second pressure flow meter, and to determine the received signal based on the water pressure and flow rate.

7. A communication method for an oilfield stratified water injection system, characterized in that, Performed by the oilfield stratified water injection system according to any one of claims 1-6, the method comprises: When the auxiliary water distributor needs to transmit signals to the ground, it sends electromagnetic wave signals to the relay water distributor. The relay water distributor receives electromagnetic wave signals, determines the signal transmitted by the auxiliary water distributor based on the electromagnetic wave signals, and changes the water injection method from the oil pipe to the casing in the well layer where the relay water distributor is located based on the signal transmitted by the auxiliary water distributor, so that the water in the oil pipe in the well layer where the relay water distributor is located is injected into the casing in a first preset manner. The control module detects changes in water pressure and flow rate in the oil pipe, and determines the signal transmitted by the relay water distributor based on the changes in water pressure and flow rate.

8. The method according to claim 7, characterized in that, Also includes: When the control module needs to transmit a signal to the water distributor, it changes the way the ground injects water into the oil pipe, so that the ground injects water into the oil pipe in a second preset manner. Each of the water distributors detects changes in water pressure and flow rate in the oil pipe, and determines the signal transmitted by the control module based on the water pressure and flow rate.

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