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 one packer layer divides the area between a casing and a tubing into at least two well layers; each well layer is provided with a water distributor. An auxiliary water distributor is used to transmit signals to a relay water distributor by wireless mode when it is needed to transmit signals to the ground. The relay water distributor is used to receive the signals transmitted by the auxiliary water distributor, and change the water injection mode of the tubing to the casing of the well layer according to the signals transmitted by the auxiliary water distributor; and a control module is used to detect the water pressure and flow in the tubing, and determine the signals transmitted by the relay water distributor according to the water pressure and flow. The embodiment of the present application adopts the relay communication principle, realizes the wireless uploading of all signals of the auxiliary water distributor in the well through the relay water distributor, avoids the problem that the wellhead pressure wave change amplitude is small and difficult to identify due to the water absorption characteristics of different reservoirs, and improves the 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, and water-drive development is the main development method for oilfields in my country. Domestic oilfields generally have multi-layered and heterogeneous characteristics. Indiscriminate water injection can lead to single-layer surges. Therefore, the widespread adoption of stratified water injection is a key and effective means to improve water-drive 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 one sealing layer is disposed within the casing and between the casing and the tubing, and the at least one sealing layer divides 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 control module is located on the ground.

[0010] The auxiliary water distributor is used to wirelessly transmit signals to the relay water distributor when it is necessary to transmit signals to the ground.

[0011] The relay water distributor is used to receive signals transmitted by the auxiliary water distributor and change the water injection method from the tubing to the casing in its well layer according to the signals 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.

[0012] 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.

[0013] Optionally, the auxiliary water distributor is used to change the water injection method from the tubing to the casing of its well when it is necessary to transmit signals to the surface, so that the water in the tubing of its well is injected into the casing in a second preset manner.

[0014] The relay water distributor is used to detect changes in water pressure and flow rate in the oil pipeline, and determines the signal transmitted by the auxiliary water distributor based on the changes in water pressure and flow rate.

[0015] Optionally, the medium absorption characteristics are best on the outside of the casing of the well layer where the relay water distributor is located.

[0016] Optionally, the control module is also used to change the water injection method from 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 third preset manner.

[0017] 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 changes in water pressure and flow rate.

[0018] Optionally, each water distributor includes a control circuit, a battery pack, a first pressure flow meter, and a valve;

[0019] The control circuit is electrically connected to the battery pack, the first pressure flow meter, and the valve, respectively.

[0020] The battery pack powers the control circuitry, the first pressure flow meter, and the valves.

[0021] The first pressure flow meter is used to detect the water pressure and flow rate in the oil pipe;

[0022] The control circuit is used to adjust the valve opening according to the signal to be transmitted to the ground when it is necessary, so that water in the oil pipe is injected into the casing in a corresponding manner.

[0023] The control circuit is also used to acquire the water pressure and flow rate measured by the first pressure flow meter, and to determine the received signal based on the water pressure and flow rate.

[0024] Optionally, each water distributor is also used to adjust the valve opening based on the signal transmitted by the control module after determining the signal transmitted by the control module.

[0025] Optionally, the control module includes a main control circuit, a main valve, and a second pressure and flow meter;

[0026] The main control circuit is used to adjust the opening of the main valve according to the signal to be transmitted to the water distributor when it is necessary to transmit the signal to the water distributor, and control the ground to inject water into the oil pipe in a third preset manner.

[0027] The second pressure flow meter is used to detect the water pressure and flow rate in the oil pipe;

[0028] 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.

[0029] 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:

[0030] When the auxiliary water distributor needs to transmit signals to the ground, it transmits the signals to the relay water distributor wirelessly.

[0031] The relay water distributor receives the signal transmitted by the auxiliary water distributor and controls 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.

[0032] 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.

[0033] Optionally, when the auxiliary water distributor needs to transmit signals to the ground, it can wirelessly transmit signals to the relay water distributor, including:

[0034] When the auxiliary water distributor needs to transmit signals to the ground, it changes the water injection method from the tubing to the casing of the well layer in which it is located, so that the water in the tubing of the well layer is injected into the casing in a second preset manner.

[0035] The signals received by the relay water distributor from the auxiliary water distributor include:

[0036] The relay water distributor detects changes in water pressure and flow rate in the oil pipe and determines the signal transmitted by the auxiliary water distributor based on these changes.

[0037] 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 ground water valve injects water into the oil pipe in a third preset manner;

[0038] 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 these changes.

[0039] In the technical solution provided by this invention embodiment, when the auxiliary water distributor needs to transmit signals to the ground, it wirelessly transmits the signals to the relay water distributor. The relay water distributor receives the signals transmitted by the auxiliary water distributor and changes the water injection method from the tubing to the casing in its well layer according to the signals 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 the changes in water pressure and flow rate in the tubing and determines the signals transmitted by the relay water distributor based on the changes in water pressure and flow rate. This invention embodiment adopts the principle of relay communication. Through short-range communication between the relay water distributor and the auxiliary water distributor, the signals of each auxiliary water distributor are transmitted to the relay water distributor. Through communication between the relay water distributor and the ground control module, the signals of the underground water distributors are wirelessly uploaded to the ground. 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 higher accuracy and efficiency. The relay water distributor can be selected from well layers with more stable signal transmission. Transmitting signals to the ground through the relay water distributor can avoid the problem of small changes in wellhead pressure waves due to different reservoir water absorption characteristics, which makes it difficult to identify. This improves the efficiency of wireless communication and also enhances the adaptability and reliability of wireless communication for multi-layer and stratified water injection.

[0040] 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

[0041] 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.

[0042] Figure 1 This is a schematic diagram of a wavecode wireless layered water injection system.

[0043] 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;

[0044] Figure 3 This is a schematic diagram of the structure of a water distributor provided in an embodiment of the present invention;

[0045] Figure 4 This is a schematic diagram of the structure of a control module provided in an embodiment of the present invention.

[0046] Figure 5A flowchart of a communication method for a stratified water injection system in an oilfield is provided in this embodiment of the invention;

[0047] Figure 6 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 7 This is a flowchart of another communication method for an oilfield stratified water injection system provided in an embodiment of the present invention;

[0049] 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.

[0050] 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

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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 2, a tubing 1 installed within the casing, at least one sealing layer, the sealing layer being installed within the casing 2 and positioned between the casing 2 and the tubing 1, the sealing layer dividing the area between the casing 2 and the tubing 1 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 control module 3 is located on the surface. The auxiliary water distributor wirelessly transmits signals to the relay water distributor P1 when signals need to be transmitted to the surface. The relay water distributor P1 receives the signals transmitted by the auxiliary water distributor and, based on the signals, changes the water injection method from the tubing 1 in its well layer to the casing 2, injecting water from the tubing 1 into the casing 2 in a first preset manner. The control module 3 detects changes in water pressure and flow rate in the tubing 1 and determines the signals transmitted by the relay water distributor based on these changes.

[0055] Among them, combined Figure 2The sealing layers installed inside casing 2 include: sealing layer 1, sealing layer 2...sealing layer n. The auxiliary water distributors include: auxiliary water distributor P2, auxiliary water distributor P3...auxiliary water distributor Pn. The wireless communication method can be flow / pressure wave or electromagnetic wave, etc. Control module 3 may include a communication controller. The distance between relay water distributor P1 and the auxiliary water distributors is short (within 100 meters). The first preset method is that relay water distributor P1 controls the injection of water from the tubing 1 of its well layer into casing 2 based on detected changes in water pressure and flow rate, for example, by adjusting the opening of the valve for injecting water into casing 2. Relay water distributor P1 can be selected from those with the most stable signal transmission to the control module 3 on the surface.

[0056] Specifically, under normal circumstances, there is water pressure and flow rate in tubing 1. Only when the auxiliary water distributor transmits a signal to the ground will the auxiliary water distributor transmit the signal to be transmitted wirelessly to the relay water distributor P1. After receiving the signal transmitted by the auxiliary water distributor, the relay water distributor P1 changes the water pressure and flow rate injected from tubing 1 to casing 2 in its well layer. The control module 3 detects the changes in water pressure and flow rate signals and decodes them. Based on the decoded signal, it determines the signal transmitted by the relay water distributor P1.

[0057] In the technical solution provided by this embodiment of the invention, when the auxiliary water distributor needs to transmit signals to the ground, it wirelessly transmits the signals to the relay water distributor P1. The relay water distributor P1 receives the signals transmitted by the auxiliary water distributor and, based on the signals transmitted by the auxiliary water distributor, changes the water injection method from the tubing 1 to the casing 2 in its well layer, causing water in the tubing 1 to be injected into the casing 2 in a first preset manner. After detecting changes in water pressure and flow rate in the tubing, the control module 3 determines the signals transmitted by the relay water distributor P1 based on the changes in water pressure and flow rate. This embodiment of the invention employs a relay communication principle, achieving signal transmission from each auxiliary water distributor to the relay water distributor P1 through short-range communication between the relay water distributor P1 and the auxiliary water distributor. Communication between the relay water distributor P1 and the ground control module enables the wireless uploading of signals from the underground water distributors to the ground. Since the distance between the water distributors is shorter than the distance between the relay water distributor P1 and the ground, the auxiliary water distributor transmits signals to the relay water distributor with higher accuracy and efficiency. The relay water distributor can be selected from the well layer with more stable signal transmission. Transmitting signals to the ground through the relay water distributor can avoid the problem of small changes in wellhead pressure waves due to different reservoir water absorption characteristics, which makes it difficult to identify. This improves the efficiency of wireless communication and also improves the adaptability and reliability of wireless communication for multi-layer and stratified water injection.

[0058] See Figure 2Based on the above embodiments, optionally, the auxiliary water distributor is used to change the water injection method from the tubing 1 to the casing 2 of its well layer when it is necessary to transmit signals to the surface, so that water in the tubing 1 of its well layer is injected into the casing 2 in a second preset manner. The relay water distributor P1 is used to detect changes in water pressure and flow rate in the tubing 1, and determine the signal transmitted by the auxiliary water distributor based on the changes in water pressure and flow rate.

[0059] Specifically, the second preset method is determined based on the signal that the auxiliary water distributor needs to transmit. When the auxiliary water distributor transmits a signal to the surface, it increases the water pressure and flow rate injected from the tubing 1 of its well layer into the casing 2, so that the water pressure and flow rate in its tubing 1 change. After the relay water distributor P1 detects the signal of the change in water pressure and flow rate, it determines the signal transmitted by the auxiliary water distributor based on the detected signal of the change in water pressure and flow rate, and controls the water in the tubing 1 of its well layer to be injected into the casing 2 in the first preset method according to the signal transmitted by the auxiliary water distributor.

[0060] In this embodiment of the invention, short-range communication between the auxiliary water distributor and the relay water distributor P1 is achieved through pressure pulses. Since the distance between the water distributors is shorter than the distance between the water distributor and the ground, the auxiliary water distributor transmits signals to the relay water distributor with high accuracy and efficiency, improving communication adaptability and efficiency. Through this method, wireless communication between 4-6 layers of stratified injection wells can be achieved.

[0061] See also Figure 2 Based on the above embodiments, optionally, the medium absorption characteristics on the outside of the casing 2 of the well layer where the relay water distributor P1 is located are the best.

[0062] In this embodiment, the layer with the best medium water absorption characteristics on the outside of the sleeve 2 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 can be the first layer or the second layer; this embodiment of the invention does not limit this.

[0063] Specifically, when water is injected into casing 2, the formation with the best water absorption capacity absorbs more water, resulting in significant changes in water pressure and flow rate in tubing 1. 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.

[0064] See also Figure 2Based 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 1 when it is necessary to transmit a signal to the water distributor, so that the ground injects water into the oil pipe 1 in a third preset manner. Each water distributor is used to detect changes in water pressure and flow rate in the oil pipe 1, and determines the signal transmitted by the control module 3 based on the changes in water pressure and flow rate.

[0065] The water distributor includes a relay water distributor P1 and auxiliary water distributors P2, P3, ..., Pn. The third preset mode is determined by the signals transmitted to the water distributor as needed.

[0066] Specifically, when the ground transmits signals to the relay water distributor P1 and the auxiliary water distributor, it increases the water pressure and flow rate injected into the oil pipe 1 so that the ground injects water into the oil pipe 1 in a third preset manner. The relay water distributor P1 and the auxiliary water distributor will respectively detect the changes in water pressure and flow rate in the oil pipe 1 of their respective well layers, and decode the detected water pressure and flow rate signals in the oil pipe 1. Based on the changes in water pressure and flow rate signals, the signal transmitted by the control module 3 is determined.

[0067] See also Figure 2 Based on the above embodiments, and exemplarily, the main communication layer is determined according to the existing water absorption characteristic curve. 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, the 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 wirelessly to the main communication layer (i.e., the relay water distributor P1). The main communication layer achieves wireless uploading through pressure pulses. Specifically, the auxiliary water distributor P2 increases the pressure and flow rate of water injected into the casing 2 to generate pressure pulse changes in the tubing 1. The nearby relay water distributor P1 identifies and decodes the pressure and flow rate changes in the tubing 1 to obtain the signal transmitted by the auxiliary water distributor P2. Auxiliary water distributor P3 increases the pressure and flow rate of water injected into casing 2, causing pressure pulse changes in tubing 1. The nearby relay water distributor P1 identifies and decodes these pressure and flow changes in tubing 1, obtaining the signal transmitted by auxiliary water distributor P3. Similarly, auxiliary water distributor Pn increases the water pressure and flow rate injected into casing 2, causing pressure pulse changes in tubing 1. The nearby relay water distributor P1 identifies and decodes these pressure and flow changes in tubing 1, obtaining the signal transmitted by auxiliary water distributor Pn. Then, relay water distributor P1 uses efficient pressure pulses to achieve wireless and efficient uploading of data from each downhole water distributor, where n is the number of auxiliary water distributors, and n is greater than or equal to 2.

[0068] Figure 3 This is a schematic diagram of a water distributor provided in an embodiment of the present invention. See also... Figure 2 and Figure 3 Based on the above embodiments, optionally, each water distributor includes a control circuit 4, a battery pack 6, a first pressure flow meter 5, and a valve 7. The control circuit 4 is electrically connected to the battery pack 6, the first pressure flow meter 5, and the valve 7. The battery pack 6 supplies power to the control circuit 4, the first pressure flow meter 5, and the valve 7. The first pressure flow meter 5 detects the water pressure and flow rate in the oil pipe 1. When a signal needs to be transmitted to the ground, the control circuit 4 adjusts the opening of the valve 7 according to the signal to be transmitted, so that water in the oil pipe 1 is injected into the casing 2 in a corresponding manner. The control circuit 4 is also used to acquire the water pressure and flow rate measured by the first pressure flow meter 5, and determine the received signal based on the water pressure and flow rate.

[0069] Each water distributor includes a relay water distributor P1 and an auxiliary water distributor.

[0070] Specifically, when the auxiliary water distributor transmits a signal to the ground, the control circuit 4 of the auxiliary water distributor adjusts the opening of its valve 7 so that the water in the oil pipe 1 is injected into the casing 2 in a second preset manner. The first pressure flow meter 5 of the relay water distributor P1 detects the changes in water pressure and flow in the oil pipe 1. After the control circuit 4 of the relay water distributor P1 obtains the signal of the change in water pressure and flow in the oil pipe 1 detected by the first pressure flow meter 5, it determines the signal transmitted by the auxiliary water distributor based on the obtained signal of the change in water pressure and flow in the oil pipe 1.

[0071] When the control module 3 transmits signals to the auxiliary water distributor and the relay water distributor P1, the control module 3 increases the water pressure and flow rate of the ground to the auxiliary water distributor and the relay water distributor, so that the ground controls the injection of water into the oil pipe in a third preset manner. The first pressure flow meter 5 of the auxiliary water distributor and the relay water distributor P1 respectively detects the changes in water pressure and flow rate in the oil pipe 1. The control circuit 4 of the auxiliary water distributor and the relay water distributor P1 respectively obtains the water pressure and flow rate change signals of the corresponding first pressure flow meter 5, and determines the signal transmitted by the control module 3 based on the obtained water pressure and flow rate change signals.

[0072] See also Figure 2 and Figure 3 Based on the above embodiments, optionally, each water distributor is also used to adjust the opening degree of valve 7 according to the signal transmitted by control module 3 after determining the signal transmitted by control module 3.

[0073] Specifically, when the signal transmitted by the control module 3 is to control the water distributor to increase or stop increasing water supply, the control circuit of the water distributor adjusts the opening degree of the corresponding valve 7 according to the signal transmitted by the control module 3.

[0074] For example, when the control module 3 does not require signals to be transmitted from each water distributor, the control module 3 sends a signal to each water distributor to stop adding water. After receiving the signal from the control module 3, the generators of each water distributor adjust the opening of their respective valves 7 to maintain the initial opening of the valves 7. When the control module 3 transmits signals to each water distributor, the control module 3 sends a signal to each water distributor to add water. After receiving the signal from the control module 3, the generators of each water distributor increase the opening of their respective valves 7 to increase the water pressure and flow rate of water injected into the casing 1 from the oil pipe 2.

[0075] Figure 4 This is a schematic diagram of the structure of a control module provided in an embodiment of the present invention. See also... Figure 2 , Figure 3 and Figure 4 Based on the above embodiments, optionally, the control module 3 includes a main control circuit 8, a main valve 10, and a second pressure and flow meter 9. The main control circuit 8 is used to adjust the opening of the main valve 10 according to the signal to be transmitted to the water distributor, so that water is injected into the oil pipe 1 from the ground in a third preset manner. The second pressure and flow meter 9 is used to detect the water pressure and flow rate in the oil pipe 1. The main control circuit 8 is also used to acquire the water pressure and flow rate measured by the second pressure and flow meter 9, and determine the received signal based on the water pressure and flow rate.

[0076] Specifically, when the control module 3 transmits signals to the auxiliary water distributor and the relay water distributor, the main control circuit 8 adjusts the opening of the main valve 10 so that the ground injects water into the oil pipe 1 in a third preset manner, that is, increases the water pressure and flow rate of the water injected into the oil pipe 1, thereby changing the water pressure and flow rate in the oil pipe 1. The relay water distributor P1 and the auxiliary water distributor detect the changes in the water pressure and flow rate in the oil pipe 1 respectively, and can determine the signal transmitted by the control module 3.

[0077] This invention also provides a communication method for an oilfield stratified water injection system. Figure 5 This invention provides a flowchart of a communication method for an oilfield stratified water injection system. (See attached diagram.) Figure 5 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:

[0078] When the S110 auxiliary water distributor needs to transmit signals to the ground, it transmits the signals wirelessly to the relay water distributor.

[0079] S120, the relay water distributor receives the signal transmitted by the auxiliary water distributor, 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.

[0080] 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.

[0081] In the technical solution provided by this invention embodiment, when the auxiliary water distributor needs to transmit signals to the ground, it wirelessly transmits the signals to the relay water distributor. The relay water distributor receives the signals transmitted by the auxiliary water distributor and changes the water injection method from the tubing to the casing in its well layer according to the signals 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 the changes in water pressure and flow rate in the tubing and determines the signals transmitted by the relay water distributor based on the changes in water pressure and flow rate. This invention embodiment adopts the principle of relay communication. Through short-range communication between the relay water distributor and the auxiliary water distributor, the signals of each auxiliary water distributor are transmitted to the relay water distributor. Through communication between the relay water distributor and the ground control module, the signals of the underground water distributors are wirelessly uploaded to the ground. 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 higher accuracy and efficiency. The relay water distributor can be selected from well layers with more stable signal transmission. Transmitting signals to the ground through the relay water distributor can avoid the problem of small changes in wellhead pressure waves due to different reservoir water absorption characteristics, which makes it difficult to identify. This improves the efficiency of wireless communication and also enhances the adaptability and reliability of wireless communication for multi-layer and stratified water injection.

[0082] Figure 6 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 6 Optionally, in the above embodiments, when the auxiliary water distributor needs to transmit signals to the ground, it wirelessly transmits the signals to the relay water distributor, including:

[0083] S1101, When it is necessary to transmit signals to the ground, the auxiliary water distributor changes the water injection method from the tubing of its well to the casing, so that the water in the tubing of its well is injected into the casing in a second preset manner.

[0084] The signals received by the relay water distributor from the auxiliary water distributor include:

[0085] S1201, the intermediate water distributor detects changes in water pressure and flow rate in the oil pipe, and determines the signal transmitted by the auxiliary water distributor based on the changes in water pressure and flow rate.

[0086] Figure 7 This is a schematic diagram of another communication method for an oilfield stratified water injection system provided in an embodiment of the present invention. See also... Figure 7 Based on the above embodiments, optionally, the communication method for oilfield stratified water injection systems also includes:

[0087] 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, causing the ground water valve to inject water into the oil pipe in a third preset mode. Each water distributor detects changes in water pressure and flow rate in the oil pipe and determines the signal to be transmitted by the control module based on these changes.

[0088] 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.

[0089] Figure 8 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 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, so as to increase the water pressure and flow rate of the water injected into the oil pipe from the ground. The water pressure and flow rate change signal of the oil pipe is transmitted to the water distributors of each layer. After receiving the water pressure and flow rate change signal of the oil pipe, each water distributor decodes it and adjusts the opening of its valve according to the decoded signal.

[0090] 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. Exemplarily, the bottom-up communication method is as follows: the auxiliary water distributor transmits water pressure and flow rate data to the relay water distributor in the main communication layer by injecting water into the casing. The relay water distributor detects the water pressure and flow rate in the tubing, determines the signal transmitted by the auxiliary water distributor, and transmits the signal to the ground control module by injecting water into the casing. The control module receives the signal.

[0091] 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.

[0092] 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 one sealing layer is disposed within the casing and between the casing and the tubing, the at least one sealing layer 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. Control module, the control module is installed on the ground; The auxiliary water distributor is used to wirelessly transmit signals to the relay water distributor when it is necessary to transmit signals to the ground; the auxiliary water distributor is used to change the water injection method from the tubing of its well layer to the casing when it is necessary to transmit signals to the ground, so that the water in the tubing of its well layer is injected into the casing in a second preset manner. The intermediate water distributor is used to detect changes in water pressure and flow rate in the oil pipe, and determines the signal transmitted by the auxiliary water distributor based on the changes in water pressure and flow rate. The relay water distributor is used to receive signals transmitted by the auxiliary water distributor and change the water injection method from the oil pipe of the well layer where the relay water distributor is located to the casing according to the signals transmitted by the auxiliary water distributor, so that the water in the oil pipe of the well layer 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 oil pipe, and to 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 third 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 changes in 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, a first pressure flow meter, and a valve; The control circuit is electrically connected to the battery pack, the first pressure flow meter, and the valve, respectively. The battery pack is used to power the control circuit, the first pressure flow meter, 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 adjust the valve opening according to the signal to be transmitted when it is necessary to transmit a signal to the ground, so that water in the oil pipe is injected into the casing in a corresponding manner. The control circuit is also used to acquire the water pressure and flow rate measured by the first pressure flow meter, and to determine the received signal based on the water pressure and flow rate.

4. The system according to claim 3, characterized in that: Each of the water distributors is also used to adjust the opening degree of the valve according to the signal transmitted by the control module after determining the signal transmitted by the control module.

5. The system according to claim 1, 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 adjust 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 ground injects water into the oil pipe in a third 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.

6. 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 1-5, the method includes: When the auxiliary water distributor needs to transmit signals to the ground, it transmits the signals to the relay water distributor wirelessly. The relay water distributor receives a signal transmitted by the auxiliary water distributor and changes the water injection method from the tubing of the well where the relay water distributor is located to the casing according to the signal transmitted by the auxiliary water distributor, so that the 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 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.

7. The method according to claim 6, characterized in that: When the auxiliary water distributor needs to transmit signals to the ground, it wirelessly transmits the signals to the relay water distributor, including: When the auxiliary water distributor needs to transmit signals to the ground, it changes the water injection method from the tubing of its well to the casing, so that the water in the tubing of its well is injected into the casing in a second preset manner. The relay water distributor receives signals transmitted by the auxiliary water distributor, including: The relay water distributor detects changes in water pressure and flow rate in the oil pipe, and determines the signal transmitted by the auxiliary water distributor based on the changes in water pressure and flow rate.

8. The method according to claim 6, characterized in that, Also includes: 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 water valve injects water into the oil pipe in a third 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 changes in water pressure and flow rate.

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