PID (Proportion Integration Differentiation)-based intelligent separate injection well optimization regulation and control method

Abstract

The invention provides an intelligent separate injection well optimization regulation and control method based on PID, and belongs to the technical field of layered intelligent water injection. The method comprises the steps that the initial water injection pressure and the opening degree of a small layer are set; the injection allocation amount and the opening adjustment upper limit of each small layer are input; collecting the flow of each small layer in real time; a PID controller is used for calculating a flow value needing to be adjusted; whether water injection pressure needs to be adjusted is judged based on the current state, and a pressure adjustment value is calculated; calculating a small-layer opening adjustment value; and the opening degree and the water injection pressure of each small layer are sequentially adjusted in a polling mode till the flow of the small layer reaches the preset injection allocation amount and the error is within the allowable range. The control efficiency is improved, manual intervention is reduced, meanwhile, the water injection pressure is minimized, system energy consumption is reduced, and the method is suitable for complex and changeable well conditions and environments.

Description

Technical Field

[0001] The present invention relates to the technical field of stratified intelligent water injection, and in particular to a PID-based intelligent sub-injection well optimization and control method. Background Art

[0002] In the existing process of regulating the injection wells, manual operation is mainly relied on, which is inefficient. In addition, the existing regulation targets are usually based only on the injection amount of each small layer, but fail to fully consider the minimization of the overall system energy consumption.

[0003] However, the control scheme based on the pre-made injection well control scheme may not accurately reflect the actual well conditions due to the complex and changeable conditions of the actual reservoir and oil wells, which leads to deviations and inconsistencies when these schemes are applied in the actual production environment. In addition, when optimizing the scheme, the commonly used traditional optimization methods (such as genetic algorithms, particle swarm optimization algorithms, etc.) also have problems such as local optimal solutions, making it difficult to ensure the global optimality of the control scheme under various complex conditions. Summary of the invention

[0004] In view of this, the present invention aims to propose a PID-based intelligent injection well optimization control method, which can solve the problems existing in the prior art, such as low manual operation efficiency, the control target not fully considering the minimization of system energy consumption, and the model not matching the actual well conditions. The method of the present invention can achieve an efficient and low-energy injection well control scheme by introducing a PID controller and integrating it with a mechanism model.

[0005] To achieve the above object, the technical solution of the present invention is implemented as follows: a PID-based intelligent injection well optimization control method, comprising the following steps:

[0006] Step S1, in the startup phase, setting the initial water injection pressure and the opening of each small layer;

[0007] Step S2, the ground control system inputs the set injection amount of each small layer and the upper limit of the small layer opening adjustment value;

[0008] Step S3, collecting the flow of each small layer under the current working system in real time through sensors;

[0009] Step S4, according to the flow rate of each small layer collected in step S3 and the injection amount value set in step S2, the flow value of the small layer to be adjusted is calculated using the PID controller. The formula of the PID simulator is:

[0010]

[0011] Among them, u i (k) is the flow value that needs to be adjusted in the small layer, e i(k) is the difference between the kth small layer flow and the injection amount, e i (k-1) is the difference between the k-1th small layer flow rate and the injection amount; K p , K i , K d They are proportional coefficient, integral coefficient and differential coefficient respectively;

[0012] Step S5, judging whether the water injection pressure needs to be adjusted according to the flow value to be adjusted calculated in step S4 and the current opening state of each small layer, and if adjustment is required, calculating the water injection pressure value that needs to be adjusted for each small layer in combination with the mechanism model;

[0013] Step S6, calculating the small layer opening value that needs to be adjusted based on the flow value to be adjusted calculated in step S4 and in combination with the mechanism model;

[0014] Step S7, each small layer repeats steps S3 to S6 in turn until the difference between the small layer flow rate and the predetermined injection amount is lower than the allowable error limit.

[0015] Furthermore, in step S1, the initial water injection pressure is set to the minimum injection pressure, and the opening of each small layer is set to 50%.

[0016] Furthermore, in step S5, if any of the following conditions is met, the water injection pressure is adjusted:

[0017] The first condition is that the opening of the small layer to be adjusted reaches the maximum, but the flow rate of the small layer does not reach the injection amount set in step S2, and the openings of other small layers all reach the maximum;

[0018] The second condition is that the opening of the small layer to be adjusted reaches the maximum, but the flow rate of the small layer does not reach the injection amount set in step S2, and the corresponding flow rates of other small layers whose openings have not reached the maximum all reach or exceed the injection amount set in step S2;

[0019] The third condition is that the flow rates of all small layers are greater than the injection volume set in step S2;

[0020] The calculation formula of the adjusted water injection pressure is:

[0021]

[0022] Where P(k) is the current water injection pressure, u i (k) is the flow value to be adjusted calculated in step S4, J i is the water absorption index corresponding to the current sublayer to be adjusted; i represents the current sublayer to be adjusted.

[0023] Furthermore, in step S6, the calculation process of the small layer opening adjustment value includes the following steps:

[0024] S61, the calculation formula of the small layer opening adjustment value is: Among them, w i (k) is the opening of the current sublayer, q i (k) is the flow rate of the current small layer, u i (k) is the current small layer flow value to be adjusted calculated in step S4;

[0025] S62, compare the small layer opening adjustment value calculated in step S61 with the small layer opening adjustment value upper limit set in step S2, Δw i =max(-Δw max ,min(Δw i ,Δw max )), where Δw max It is the upper limit of the small layer opening adjustment value;

[0026] S63, the calculation formula of the adjusted small layer opening is w i (k+1)=min(100,max(w i (k)+Δw i ,0)).

[0027] Compared with the prior art, the PID-based intelligent injection well optimization control method described in the present invention has the following advantages:

[0028] (1) The method of the present invention can realize intelligent optimization and control of injection wells, effectively improve control efficiency, and reduce manual intervention;

[0029] (2) The method of the present invention can ensure that the water injection amount of each small layer reaches the predetermined injection amount while minimizing the water injection pressure, thereby effectively reducing the energy consumption of the system;

[0030] (3) The method of the present invention adopts a PID controller in the control process, and adjusts the working system of the water injection well according to the real-time flow feedback data of the actual formation, which can adapt to changes in complex well conditions.

[0031] (4) The method described in the present invention combines the PID controller with the mechanism model to calculate the control quantity, which has higher control efficiency and control accuracy than the existing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0033] Figure 1 It is a flow chart of the PID-based intelligent injection well optimization control method of the present invention;

[0034] Figure 2It is a diagram showing changes in water injection pressure, small layer opening and small layer flow rate according to the present invention. DETAILED DESCRIPTION

[0035] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0036] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0037] The present invention provides a PID-based intelligent injection well optimization and control system, comprising a processor and a memory for storing processor executable instructions. When the instructions are executed by the processor, the steps of a PID-based intelligent injection well optimization and control method described in the present invention are implemented.

[0038] like Figure 1 As shown, the present invention is a PID-based intelligent injection well optimization control method, comprising the following steps:

[0039] Step S1, when the PID-based intelligent injection well optimization and control system of the present invention is first started, the water injection pressure is first set to the minimum injection pressure value allowed by the system through the ground control system to ensure the minimum energy consumption of the system, and at the same time, the opening of each small layer is set to 50%;

[0040] Step S2: The ground control system receives and inputs the target injection amount for each sub-layer. And set the upper limit of the small layer opening adjustment value Δw max ;

[0041] Step S3, by installing high-precision flow sensors on each sub-layer of the injection well, real-time collection of the flow rate q of each sub-layer under the current working system i (k), where k represents time or sampling number;

[0042] Step S4: according to the flow rate q of each small layer collected in step S3 i (k) and the injection amount value set in step S2 Calculate the difference between the current flow rate and the injection volume of the current small layer Use the PID controller to calculate the flow value u that needs to be adjusted in the current small layer i (k), the specific calculation formula is:

[0043]

[0044] Among them, u i (k) is the flow value that needs to be adjusted in the small layer, e i (k) is the difference between the kth small layer flow and the injection amount, ei (k-1) is the difference between the k-1th small layer flow rate and the injection amount; K p , K i , K d They are proportional coefficient, integral coefficient and differential coefficient respectively;

[0045] Figure 2 In the example shown, K p The value is 1, K i and K d The average value is 0;

[0046] Step S5, judging whether the water injection pressure needs to be adjusted according to the flow value to be adjusted calculated in step S4 and the current opening state of each small layer, and if adjustment is required, calculating the water injection pressure value that needs to be adjusted for each small layer in combination with the mechanism model;

[0047] If any of the following conditions is met, the water injection pressure is adjusted:

[0048] ① The opening of the small layer to be adjusted reaches the maximum, but the flow rate of the small layer does not reach the injection amount set in step S2, and the openings of other small layers have all reached the maximum;

[0049] ② The opening corresponding to the small layer to be adjusted reaches the maximum, but the flow rate of the small layer does not reach the injection amount set in step S2, and the corresponding flow rates of other small layers whose openings have not reached the maximum all reach or exceed the injection amount set in step S2;

[0050] ③ The flow rates of all small layers are greater than the injection volume set in step S2;

[0051] The calculation formula of the adjusted water injection pressure is:

[0052]

[0053] Where P(k) is the current water injection pressure, u i (k) is the flow value to be adjusted calculated in step S4, J i is the water absorption index corresponding to the current sublayer to be adjusted; i represents the current sublayer to be adjusted.

[0054] Step S6, according to the flow value of the current small layer that needs to be adjusted calculated in step S4, the small layer opening value that needs to be adjusted is calculated in combination with the mechanism model; the specific calculation process includes:

[0055] S61, using formula Calculate the small layer opening adjustment value, where w i (k) is the opening of the current sublayer, q i (k) is the flow rate of the current small layer, u i (k) is the current small layer flow value to be adjusted calculated in step S4;

[0056] S62, compare the small layer opening adjustment value calculated in step S61 with the small layer opening adjustment value upper limit set in step S2, Δw i =max(-Δw max ,min(Δw i ,Δw max )), where Δw max It is the upper limit of the small layer opening adjustment value;

[0057] S63, the calculation formula of the adjusted small layer opening is w i (k+1)=min(100,max(w i (k)+Δw i ,0)).

[0058] Step S7, the system performs patrol control on each small layer in turn according to the above steps S3 to S6, until the difference between the small layer flow and the predetermined injection amount is lower than the allowable error limit. In each patrol, the steps of flow collection, PID calculation, water injection pressure adjustment and small layer opening adjustment are repeated until the difference between the flow of all small layers and the predetermined injection amount is lower than the preset allowable error limit. At this point, it is considered that the system has reached a stable state and the control process is over.

[0059] Figure 2 In the example, the injection volume of each sub-layer of the injection well is 110m 3 / d, 650m 3 / d and 50m 3 / d, flow data is collected every 2s, and the upper limit of each small layer opening adjustment value is 2%. After regulation by the method of the present invention, the injection rate reaches 100%, the final water injection pressure is 7.5MPa, and the openings of each small layer are 9%, 80% and 100% respectively. The entire regulation process takes only about 10 minutes, which greatly improves the regulation efficiency, and minimizes the water injection pressure and system energy consumption while ensuring that the injection is achieved.

[0060] Through the above steps, the present invention can realize intelligent optimization and control of injection wells, effectively improve the control efficiency, and reduce manual intervention; while ensuring that the water injection volume of each small layer reaches the predetermined injection volume, the water injection pressure is minimized, which can effectively reduce the energy consumption of the system; a PID controller is used in the control process to adjust the working system of the water injection well according to the real-time flow feedback data of the actual formation, which can adapt to changes in complex well conditions.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A PID-based intelligent injection well optimization control method, characterized in that: The following steps are involved: Step S1, in the startup phase, setting the initial water injection pressure and the opening of each small layer; Step S2, the ground control system inputs the set injection amount of each small layer and the upper limit of the small layer opening adjustment value; Step S3, collecting the flow of each small layer under the current working system in real time through sensors; Step S4, according to the flow rate of each small layer collected in step S3 and the injection amount value set in step S2, the flow value of the small layer to be adjusted is calculated using the PID controller. The formula of the PID simulator is: Among them, u i (k) is the flow value that needs to be adjusted in the small layer, e i (k) is the difference between the kth small layer flow and the injection amount, e i (k-1) is the difference between the k-1th small layer flow rate and the injection amount; K p , K i , K d They are proportional coefficient, integral coefficient and differential coefficient respectively; Step S5, judging whether the water injection pressure needs to be adjusted according to the flow value to be adjusted calculated in step S4 and the current opening state of each small layer, and if adjustment is required, calculating the water injection pressure value that needs to be adjusted for each small layer in combination with the mechanism model; Step S6, calculating the small layer opening value that needs to be adjusted based on the flow value to be adjusted calculated in step S4 and in combination with the mechanism model; Step S7, each small layer repeats steps S3 to S6 in turn until the difference between the small layer flow rate and the predetermined injection amount is lower than the allowable error limit.

2. The PID-based intelligent injection well optimization control method according to claim 1 is characterized in that: In step S1, the initial water injection pressure is set to the minimum injection pressure, and the opening of each small layer is set to 50%.

3. The PID-based intelligent injection well optimization control method according to claim 1 is characterized in that: In step S5, if any of the following conditions is met, the water injection pressure is adjusted: The first condition is that the opening of the small layer to be adjusted reaches the maximum, but the flow rate of the small layer does not reach the injection amount set in step S2, and the openings of other small layers all reach the maximum; The second condition is that the opening of the small layer to be adjusted reaches the maximum, but the flow rate of the small layer does not reach the injection amount set in step S2, and the corresponding flow rates of other small layers whose openings have not reached the maximum all reach or exceed the injection amount set in step S2; The third condition is that the flow rates of all small layers are greater than the injection volume set in step S2; The calculation formula of the adjusted water injection pressure is: Where P(k) is the current water injection pressure, u i (k) is the flow value to be adjusted calculated in step S4, J i is the water absorption index corresponding to the current sublayer to be adjusted; i represents the current sublayer to be adjusted.

4. The PID-based intelligent injection well optimization control method according to claim 3 is characterized by: In step S6, the calculation process of the small layer opening adjustment value includes the following steps: S61, the calculation formula of the small layer opening adjustment value is: Among them, w i (k) is the opening of the current sublayer, q i (k) is the flow rate of the current small layer, u i (k) is the current small layer flow value to be adjusted calculated in step S4; S62, compare the small layer opening adjustment value calculated in step S61 with the small layer opening adjustment value upper limit set in step S2, Δw i =max(-Δw max ,min(Δw i ,Δw max )), where Δw max The upper limit of the small layer opening adjustment value; S63, the calculation formula of the adjusted small layer opening is w i (k+1)=min(100,max(w i (k)+Δw i ,0)).

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