Coiled tubing coiling tension control method for self-adaptive speed regulation of mandrel

Abstract

The invention provides a coiled tubing coiling tension control method for self-adaptive speed regulation of a mandrel. Comprising the following steps: step 1, establishing an equation satisfied by the tension of the coiled tubing; 2, an expected continuous pipe tension adjusting system is established; step 3, establishing an online estimator of a forward offset proportional coefficient value; and 4, designing a core axis speed self-adaptive speed regulation method for active compensation of the forward offset proportionality coefficient of the continuous pipe. According to the method, the on-line estimator of the forward offset proportional coefficient value is established, the estimated value of the forward offset proportional coefficient is obtained in real time, active compensation of the core shaft line speed on the forward offset proportional coefficient of the continuous pipe is achieved, and the tension adjusting precision of the continuous pipe under the forward offset condition is improved. In the method for regulating the speed of the core shaft, an active compensation part for the linear speed deviation condition of clamping and conveying equipment and a continuous pipe tension feedback regulation part are introduced, and the stability and the control precision of a tension regulation system are improved.

Description

Technical Field

[0001] The invention relates to the design field of a continuous tube winding tension control method, and in particular to a continuous tube winding tension control method with a mandrel adaptive speed regulation. Background Art

[0002] Continuous pipe, also known as flexible pipe, flexible pipe or coil, is a new generation of pipe in petroleum engineering. It uses high-frequency induction welding technology to continuously form and weld several thousand meters of strip steel. It is continuously produced on the production line and rolled and wound on a reel according to a certain length for delivery. The length of a single pipe is generally 2000-9000m. The coiling process of continuous pipe is a key link in its production and processing process, and its core is the stable control of coiling tension. During the coiling process, by adjusting the core axis speed, the core axis speed and the clamping equipment line speed have a certain difference, and then the continuous pipe will undergo moderate deformation to form a stable tension. Therefore, the key issue in the stable control of coiling tension is the core axis speed regulation problem.

[0003] In the actual winding process, the continuous tube at the clamping device will deviate forward, which will affect the stable control of tension. Although the forward offset of the continuous tube can often be obtained through engineering calibration, the impact of the proportional coefficient of the offset on the tension is immeasurable and unobtainable. Under the currently widely used mandrel speed control method of proportional-integral feedback, the influence of the unknown forward offset proportional coefficient is not considered, resulting in the inability to maintain high-precision tension control results. In view of the unmeasurable and unobtainable forward offset proportional coefficient of the continuous tube, how to design a new mandrel speed control method to achieve stable control of the continuous tube winding tension and improve the accuracy of tension adjustment is a practical engineering problem to be solved. Summary of the invention

[0004] The purpose of the present invention is to provide a coiled tube winding tension control method with mandrel adaptive speed regulation. The present invention is aimed at the phenomenon of forward offset during coiled tube winding, and the proportional coefficient value of the offset to the tension is unknown, which leads to a decrease in the tension control accuracy during the winding process. The present invention obtains an estimated value of the forward offset proportional coefficient of the coiled tube through an estimator of the forward offset proportional coefficient value of the coiled tube. Further constructing a desired coiled tube tension adjustment system, a mandrel axis speed adaptive speed regulation method for active compensation of the forward offset proportional coefficient of the coiled tube improves the tension control accuracy for the case of unknown forward offset proportional coefficient value of the coiled tube. The mandrel axis speed adaptive speed regulation method includes three parts: active compensation for the forward offset proportional coefficient of the coiled tube, active compensation for the linear speed offset of the clamping device, and desired feedback adjustment of the coiled tube tension.

[0005] The present invention is achieved through the following technical solutions:

[0006] The present invention relates to a method for controlling the coiling tension of a continuous tube with a mandrel adaptively regulating speed, comprising the following steps:

[0007] Step 1, establishing an equation satisfied by the coiled tubing tension;

[0008] Step 2, establishing a desired coiled tubing tension adjustment system;

[0009] Step 3, establishing an online estimator of the forward offset proportional coefficient value;

[0010] Step 4, designing a core axis speed adaptive speed regulation method for active compensation of the coiled tubing forward offset proportional coefficient.

[0011] Preferably, in step 1, the equation satisfied by the coiled tubing tension is established, and equation (1) is as follows:

[0012]

[0013] Wherein, F(t)∈R is the tension of the coiled tube at time t, v1(t)∈R is the linear velocity of the clamping and conveying device at time t, v2(t)∈R is the axial velocity of the mandrel at time t, S∈R is the cross-sectional area of ​​the coiled tube, K∈R is the elastic coefficient of the coiled tube, L∈R is the distance from the clamping and conveying device to the mandrel, P∈R is the forward offset of the coiled tube during transportation, and M∈R is the proportional coefficient of the unmeasurable forward offset of the coiled tube.

[0014] Preferably, in step 2, the desired coiled tubing tension adjustment system is established, and equation (2) is as follows:

[0015]

[0016] where F p (t)∈R is the expected tension of the coiled tube at time t, k p ∈R is the desired coiled tubing tension closed-loop adjustment speed coefficient.

[0017] Preferably, in step 3, the online estimator of the forward offset proportional coefficient value is established, and its equation (3) is as follows:

[0018]

[0019] in is the estimated value of the forward offset proportional coefficient at time t given by the estimator, and γ∈R is the gain adjustment parameter of the forward offset proportional coefficient value estimator.

[0020] Preferably, in step 4, the specific method of designing the method for adaptively regulating the core axis speed for active compensation of the forward offset proportional coefficient of the coiled tube is:

[0021] According to the coiled tube tension equation (1), the desired coiled tube tension adjustment system obtained in equation (2) and the estimated value of the forward offset proportional coefficient at time t obtained in step (3), a core axis speed adaptive speed control method for active compensation of the coiled tube forward offset proportional coefficient is designed, and its equation (4) is as follows:

[0022]

[0023] in The active compensation for the forward displacement proportional coefficient of the coiled tube is realized, and (1+P)v1(t) is realized to actively compensate for the linear speed deviation of the clamping and conveying equipment. Achieve the desired coiled tubing tension feedback adjustment portion.

[0024] In the above formula of the present invention, the symbols are explained as follows:

[0025] R: the set of all real numbers;

[0026] t: running time of the winding system, t∈[0,∞);

[0027] F(t): The tension of the coiled tube at time t, F(t)∈R;

[0028] v1(t): Linear velocity of the clamping and conveying equipment at time t, v1(t)∈R;

[0029] v2(t): the velocity of the core axis at time t, v2(t)∈R;

[0030] S: cross-sectional area of ​​the continuous tube, S∈R;

[0031] K: elastic modulus of the coiled tube, K∈R;

[0032] L: distance from the clamping device to the mandrel, L∈R;

[0033] P: forward displacement of the coiled tube during transportation, P∈R;

[0034] M: unmeasurable coiled tube forward offset proportionality coefficient value, M∈R;

[0035] F p (t): the expected tension of the coiled tube at time t, F p (t)∈R;

[0036] k p : Expected coiled tubing tension closed-loop adjustment speed coefficient, k p ∈R;

[0037] The estimated value of the forward offset proportional coefficient at time t given by the estimator, γ: Gain adjustment parameter of the forward offset scale factor value estimator, γ∈R;

[0038] The present invention takes into account the forward deflection of the coiled tube at the clamping device, designs an estimator of the forward deflection proportional coefficient of the coiled tube, and then obtains the estimated value of the forward deflection proportional coefficient of the coiled tube. According to the desired coiled tube tension adjustment system, a core axis speed adaptive speed control method for active compensation of the forward deflection proportional coefficient of the coiled tube is invented. The core axis speed adaptive speed control method includes three parts: active compensation of the forward deflection proportional coefficient of the coiled tube, active compensation of the linear speed deviation of the clamping device, and desired coiled tube tension feedback adjustment.

[0039] The present invention has the following advantages:

[0040] (1) The present invention establishes an online estimator for the forward offset proportional coefficient value, obtains the estimated value of the forward offset proportional coefficient in real time, realizes active compensation of the core axis speed for the forward offset proportional coefficient of the coiled tube, and improves the tension adjustment accuracy when the coiled tube is deflected forward.

[0041] (2) The present invention introduces active compensation for the linear speed deviation of the clamping and conveying equipment and a continuous tube tension feedback adjustment part in the core axis speed regulation method, thereby improving the stability and control accuracy of the tension regulation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a flow chart of the method of the present invention;

[0043] Figure 2 It is a control structure diagram of the method of the present invention;

[0044] Figure 3 It is a continuous tube tension coiling test device of the method of the present invention;

[0045] Figure 4 It is a diagram of the coiled tube tension control results of the method of the present invention and the proportional-integral feedback method under scenario one and scenario two. DETAILED DESCRIPTION

[0046] The present invention is described in detail below in conjunction with specific embodiments. It should be noted that the following embodiments are only further descriptions of the present invention, but the protection scope of the present invention is not limited to the following embodiments.

[0047] Example

[0048] This embodiment relates to a method for controlling the coiling tension of a continuous tube with a mandrel adaptively adjusting the speed. Figure 1 and Figure 2 As shown, the following steps are included:

[0049] Step 1, establishing an equation satisfied by the coiled tubing tension;

[0050] Step 2, establishing a desired coiled tubing tension adjustment system;

[0051] Step 3, establishing an online estimator of the forward offset proportional coefficient value;

[0052] Step 4, designing a core axis speed adaptive speed regulation method for active compensation of the coiled tubing forward offset proportional coefficient.

[0053] The present invention takes specific operation steps as an example to expand the description of the method of the present invention, and the detailed steps are as follows:

[0054] The actual parameters of the coiling system and the continuous tube are: S = 550 ((mm) 2 ), K = 1.9 × 10 5 (N / (mm) 2 ), L = 12 (m), P = 0.005 (m), v1 = 8 (m / s), F p (t) = 9 × 10 5 (Newton), (Newton / second).

[0055] Step 1: Establish the equation that the coiled tube tension satisfies. Using the actual parameters of the coiling system and the coiled tube, the coiled tube tension equation can be obtained as follows:

[0056]

[0057] Where M is the proportional coefficient value of the unmeasurable coiled tube forward offset.

[0058] Step 2: Establish the desired coiled tubing tension adjustment system:

[0059]

[0060] The desired coiled tube tension closed-loop adjustment speed coefficient k is selected p =2.8.

[0061] Step 3: Establish an online estimator for the forward offset scale factor value:

[0062]

[0063] The gain adjustment parameter γ of the forward offset proportional coefficient value estimator is 8.

[0064] Step 4: Based on the coiled tube tension equation obtained in the specific implementation step 1, the desired coiled tube tension adjustment system obtained in the specific implementation step 2, and the estimated value of the forward offset proportional coefficient at time t obtained in the specific implementation step 3 Design of an adaptive speed control method for the core axis speed with active compensation of the forward offset proportional coefficient of the coiled tube:

[0065]

[0066] The mandrel axis speed designed above is input into the mandrel motor system to realize the tension control of the winding process.

[0067] In order to further study the applicability of the method of the present invention, a comparative experiment between the proportional-integral feedback control method and the method of the present invention is further conducted. In the experiment, two scenarios are designed:

[0068] Scenario 1: Coiled tubing forward offset proportional coefficient value M = 0.0005;

[0069] Scenario 2: The forward offset proportional coefficient value of the coiled tubing is M = 0.005.

[0070] Figure 4 The coiled tube tension adjustment results under scenario one and scenario two are given.

[0071] Since the forward offset proportional coefficient of the coiled tube is unknown, and the forward offset proportional coefficients of scenario 1 and scenario 2 are different, the tension control response under the proportional-integral feedback control method is slow, and the transient control performance in the initial stage is poor. The present invention obtains the estimated value of the forward offset proportional coefficient of the coiled tube in real time by inventing an estimator of the forward offset proportional coefficient of the coiled tube, and designs a core axis speed adaptive speed regulation method for active compensation of the forward offset proportional coefficient of the coiled tube. Figure 4 The control results in the paper show that the method of the present invention can realize fast tracking control of tension under the condition of unknown forward offset proportional coefficient, with good transient tracking response and small stable tracking error.

[0072] In order to verify the applicability of the method of the present invention, an experimental verification is carried out on the coiled tubing tension adjustment system. The experimental equipment is shown in Figure 3 .

[0073] In summary, the present invention establishes an online estimator of the forward offset proportional coefficient value, obtains the estimated value of the forward offset proportional coefficient in real time, realizes the active compensation of the core axis speed for the coiled tube forward offset proportional coefficient, and improves the tension adjustment accuracy when the coiled tube is forward offset. In the core axis speed regulation method, the present invention introduces the active compensation for the linear speed offset of the clamping device and the coiled tube tension feedback adjustment part, which improves the stability and control accuracy of the tension adjustment system.

[0074] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various modifications or variations within the scope of the claims, which will not affect the essence of the present invention.

Claims

1. A method for controlling the coiling tension of a continuous tube with adaptive mandrel speed regulation, characterized in that: The following steps are involved: Step 1, establishing an equation satisfied by the coiled tubing tension; Step 2, establishing a desired coiled tubing tension adjustment system; Step 3, establishing an online estimator of the forward offset proportional coefficient value; Step 4, designing a core axis speed adaptive speed regulation method for active compensation of the coiled tubing forward offset proportional coefficient.

2. The method for controlling the coiled tube tension with mandrel adaptive speed regulation according to claim 1, characterized in that: In step 1, the equation satisfied by the coiled tubing tension is established, and its equation (1) is as follows: Wherein, F(t)∈R is the tension of the coiled tube at time t, v1(t)∈R is the linear velocity of the clamping and conveying device at time t, v2(t)∈R is the axial velocity of the mandrel at time t, S∈R is the cross-sectional area of ​​the coiled tube, K∈R is the elastic coefficient of the coiled tube, L∈R is the distance from the clamping and conveying device to the mandrel, P∈R is the forward offset of the coiled tube during transportation, and M∈R is the proportional coefficient of the unmeasurable forward offset of the coiled tube.

3. The method for controlling coiled tube winding tension with mandrel adaptive speed regulation according to claim 1, characterized in that: In step 2, the desired coiled tubing tension adjustment system is established, and equation (2) is as follows: where F p (t)∈R is the expected tension of the coiled tube at time t, k p ∈R is the desired coiled tubing tension closed-loop adjustment speed coefficient.

4. The method for controlling coiled tube tension with mandrel adaptive speed regulation according to claim 1, characterized in that: In step 3, the online estimator of the forward offset proportional coefficient value is established, and its equation (3) is as follows: in is the estimated value of the forward offset proportional coefficient at time t given by the estimator, and γ∈R is the gain adjustment parameter of the forward offset proportional coefficient value estimator.

5. The method for controlling coiled tube tension with mandrel adaptive speed regulation according to claim 1, characterized in that: In step 4, the specific method of designing the core axis speed adaptive speed regulation method for active compensation of the forward offset proportional coefficient of the coiled tube is: According to the coiled tube tension equation (1), the desired coiled tube tension adjustment system obtained in equation (2) and the estimated value of the forward offset proportional coefficient at time t obtained in step (3), a core axis speed adaptive speed control method for active compensation of the coiled tube forward offset proportional coefficient is designed, and its equation (4) is as follows: in The active compensation for the forward displacement proportional coefficient of the coiled tube is realized, and (1+P)v1(t) is realized to actively compensate for the linear speed deviation of the clamping and conveying equipment. Achieve the desired coiled tubing tension feedback adjustment portion.

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