Testing device and testing method for expansion rate of swellable alloy

Abstract

The embodiment of the invention provides a device and a method for testing the expansion rate of a swellable alloy, and belongs to the field of expansion rate testing. The test device comprises: a reaction chamber comprising a sample chamber and a piston rod, the sample chamber having a hollow cavity for accommodating a swellable alloy, one end of the piston rod being in contact with the swellable alloy to move in response to the expansion of the swellable alloy; the electrochemical workstation comprises a counter electrode and a working electrode which are positioned in the reaction solution, the working electrode is fixed at the other end of the piston rod, and the electrochemical workstation is used for acquiring a resistance value between the working electrode and the counter electrode; and the processor is used for determining the expansion rate of the swellable alloy according to the resistance value acquired by the electrochemical workstation. The testing device can meet real-time monitoring of the expansion coefficient of the swellable alloy in the high-temperature and high-pressure environment, and can simply and efficiently measure the expansion coefficient of the swellable alloy in different set temperature and set pressure environments.

Description

Technical Field

[0001] This invention relates to the field of expansion rate testing technology, and more specifically to a testing device and method for the expansion rate of a swellable alloy. Background Technology

[0002] Packers are commonly used tools in oil well drilling and completion, their function being to isolate the annulus of the casing or the wellbore annulus. Existing packer sealing elements are mainly elastomers such as rubber, achieving annular sealing through physical methods such as mechanical compression or hydraulic expansion. However, elastomers like rubber experience performance degradation under harsh conditions such as high temperature, high pressure, and high salinity, failing to meet the long-term application requirements of downhole high-temperature and high-pressure (>200℃ / 70MPa). Packer failure can lead to the cessation or failure of oil and gas well construction or production, causing significant losses. To address this, existing technology proposes a packer technology based on a metal-swellable material. This metal undergoes a chemical hydration reaction with brine (containing Cl ions) to produce water-insoluble oxides or hydroxides, with the product significantly increasing in volume compared to the original metal, thus serving as the sealing element for annular sealing.

[0003] Expansion rate is a crucial parameter reflecting the performance of swelling alloys. It effectively reflects both the sealing capability of swelling packers and the swelling reaction process, enhancing our understanding of the reaction mechanism. However, existing expansion rate measurement methods are mostly designed for continuous elastomer materials. There are no effective methods for measuring the particulate reaction products of metal swelling materials, and they also cannot simulate real-time expansion performance testing under actual high temperature and high pressure environments. Summary of the Invention

[0004] The purpose of this invention is to provide a testing device and method for the expansion rate of a swellable alloy, which can determine the volume expansion rate of particulate reaction products and monitor the expansion performance in real time under high temperature and high pressure conditions.

[0005] To achieve the above objectives, embodiments of the present invention provide a testing device for the expansion rate of a swellable alloy. The testing device includes: a reaction chamber comprising a sample chamber and a piston rod, the sample chamber having a hollow cavity for accommodating the swellable alloy, one end of the piston rod being in contact with the swellable alloy to move in response to the expansion of the swellable alloy; an electrochemical workstation comprising a counter electrode and a working electrode located in a reaction solution, the working electrode being fixed to the other end of the piston rod, the electrochemical workstation being used to acquire the resistance value between the working electrode and the counter electrode, wherein the reaction solution has a set temperature and a set pressure; and a processor for determining the expansion rate of the swellable alloy based on the resistance value acquired by the electrochemical workstation.

[0006] Optionally, the reaction chamber further includes a piston tube having a hollow cavity for accommodating the piston rod and guiding its movement, wherein the cross-section of the hollow cavity of the sample chamber, the cross-section of the hollow cavity of the piston tube, and the cross-section of the piston rod have the same shape and size.

[0007] Optionally, one end of the sample chamber is open, and the piston tube is connected to one end of the sample chamber opening by a thread. The cross-section of the hollow cavity of the sample chamber, the cross-section of the hollow cavity of the piston tube, and the cross-section of the piston rod are all circular, elliptical, triangular, quadrilateral, or hexagonal.

[0008] Optionally, the sample chamber includes multiple liquid inlets distributed on the outer surface of one end of the sample chamber, wherein the multiple liquid inlets are multiple holes with an inner diameter smaller than a set value.

[0009] Optionally, the electrochemical workstation further includes a reference electrode located between the working electrode and the counter electrode, wherein the reference electrode, the working electrode, and the counter electrode are located in the same plane.

[0010] Optionally, the materials of the counter electrode and the working electrode are platinum or carbon, and the material of the reference electrode is saturated calomel or Ag / AgCl; the reaction solution is a halide ion salt solution, preferably a KCl solution or a NaCl solution.

[0011] Optionally, the processor is further configured to determine the expansion rate of the swellable alloy based on a first fitting coefficient and a second fitting coefficient between the test distance between the working electrode and the counter electrode and the test resistance of the reaction solution, and the measured resistance value of the reaction solution between the working electrode and the counter electrode.

[0012] Optionally, the first fitting coefficient and the second fitting coefficient are determined by: adjusting the distance between the working electrode and the counter electrode multiple times to obtain multiple test distances; obtaining the resistance value of the reaction solution at the set temperature and the set pressure after each distance adjustment using the electrochemical workstation to obtain multiple test resistance values; and performing linear fitting on the multiple test distances and the multiple test resistance values ​​to determine the first fitting coefficient and the second fitting coefficient.

[0013] Optionally, the processor is further configured to determine the expansion rate δ of the swellable alloy based on a first fitting coefficient a and a second fitting coefficient b between the test distance between the working electrode and the counter electrode and the test resistance of the reaction solution, and the measured resistance value R of the reaction solution between the working electrode and the counter electrode, using the following formula:

[0014]

[0015] Where x2 is the distance between the counter electrode and the tail of the reaction chamber, L0 is the initial size of the reaction chamber, and s0 is the initial size of the swellable alloy.

[0016] On the other hand, the present invention provides a method for testing the expansion rate of a swellable alloy, the method comprising: placing the swellable alloy in the hollow cavity of a sample chamber, contacting one end of a piston rod with the swellable alloy, and fixing the working electrode of an electrochemical workstation to the other end of the piston rod; obtaining the resistance value between the counter electrode and the working electrode of the electrochemical workstation, wherein the counter electrode and the working electrode are located in a reaction solution having a set temperature and a set pressure; and determining the expansion rate of the swellable alloy based on the obtained resistance value.

[0017] Through the above technical solutions, the testing device and testing method provided by the present invention can meet the real-time monitoring of the expansion coefficient of swellable alloys under high temperature and high pressure environments. By establishing the mapping relationship between the solution resistance and the distance between the working electrode and the control electrode, the expansion rate of swellable alloys under high temperature and high pressure environments can be characterized in real time, and the expansion coefficient of swellable alloys under different set temperatures and pressure environments can be determined simply and efficiently.

[0018] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0020] Figure 1 This is a schematic diagram of a device for testing the expansion rate of a swellable alloy according to an embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of the structure of a swellable alloy reaction chamber according to an embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of the layout of a device for testing the expansion rate of a swellable alloy under high pressure, according to an embodiment of the present invention.

[0023] Figures 4a-4b This is an electrochemical impedance spectroscopy diagram obtained by manually adjusting the electrode distance according to an embodiment of the present invention.

[0024] Figure 5This is an equivalent circuit diagram for electrochemical impedance measurement provided according to an embodiment of the present invention.

[0025] Figures 6a-6b These are electrochemical impedance spectroscopy diagrams measured at different time periods according to an embodiment of the present invention.

[0026] Figure 7 This is a relationship between expansion rate and solution resistance provided according to an embodiment of the present invention.

[0027] Figure 8 This is a schematic flowchart of a method for testing the expansion rate of a swellable alloy according to an embodiment of the present invention.

[0028] Explanation of reference numerals in the attached figures

[0029] A testing device for the expansion rate of 100-swellable alloys;

[0030] 10 - Reaction chamber; 20 - Electrochemical workstation; 30 - Processor;

[0031] 1-Sample chamber; 2-Swellable alloy; 3-Piston rod; 4-Piston tube;

[0032] 5-High temperature and high pressure reactor; 6-Counter electrode; 7-Reference electrode; 8-Working electrode; 9-Base;

[0033] 11-Solution resistance; 12-Charge transfer resistance; 13-Impedance of swellable alloy products; 14-Constant phase angle element. Detailed Implementation

[0034] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0035] When applying metal-swellable materials in practice, the inventors discovered that although the hydration reaction products of these materials exhibit excellent thermal stability, and packers made from them are highly adaptable to different wellbores, effectively solving the annular sealing problem in high-temperature, high-pressure oil and gas wells and small-gap wells, there is no effective method for measuring these particulate reaction products. Furthermore, it is impossible to simulate real-time expansion performance testing under actual high-temperature and high-pressure environments.

[0036] To address this, the present invention first provides a testing device 100 for the expansion rate of a swellable alloy, such as... Figure 1 As shown, the testing apparatus may include: a reaction chamber 10 for containing a swellable alloy; an electrochemical workstation 20 for acquiring resistance values; and a processor 30 for determining the expansion rate of the swellable alloy based on the resistance values ​​acquired by the electrochemical workstation 20.

[0037] Among them, such as Figure 2 As shown, the reaction chamber 10 may include a sample chamber 1 and a piston rod 3. The sample chamber 1 has a hollow cavity for containing the swellable alloy 2. One end of the piston rod 3 is in contact with the swellable alloy 2 and moves in response to the expansion of the swellable alloy 2; that is, once the swellable alloy 2 begins to react, it pushes the piston rod 3 to move. In one embodiment, the sample chamber 1 may be canister-shaped and open at one end to restrict the expansion of the swellable alloy 2 to movement only along the opening direction. In one embodiment, the sample chamber 1 may include multiple inlets to allow the reaction solution to continuously enter the reaction chamber and react with the swellable alloy material. The multiple inlets are multiple holes with an inner diameter smaller than a set value, and the multiple inlets may be distributed on the outer surface of one end of the sample chamber 1. For example, as... Figure 2 As shown, several small holes can be provided on the left end face and outer surface of the sample chamber 1 to serve as liquid inlets.

[0038] In one embodiment, the reaction chamber 10 may further include a piston tube 4 having a hollow cavity for accommodating the piston rod 3 and guiding the movement of the piston rod 3. In one embodiment, the piston tube 4 is threaded to one end of the opening of the sample chamber 1, or it may be connected in other ways that achieve the purpose of the present invention.

[0039] The piston rod 3 is placed inside the piston tube 4, with its head flush with the opening of the sample chamber 1. The hollow cavity cross-sections of the sample chamber, the piston tube, and the piston rod have the same shape and size to prevent the reaction products from being obstructed by the inner wall during their propagation towards the piston rod. For example, the hollow cavity cross-sections of the sample chamber, the piston tube, and the piston rod can all be circular, elliptical, triangular, quadrilateral, or hexagonal.

[0040] In one embodiment, a high-temperature and high-pressure reactor 5 may be installed outside the reaction chamber 10 to simulate the high-temperature and high-pressure environment of the swellable alloy in practical applications. The high-temperature and high-pressure reactor 5 contains a reaction solution, which continuously enters the reaction chamber 10 through the inlet and reacts with the swellable alloy 2. For example, the temperature of the reaction solution can be controlled by an external power source, thereby achieving a set temperature, such as a high-temperature environment greater than 200°C; a high-pressure environment can be simulated by injecting the reaction solution, thereby achieving a set pressure, such as a high-pressure environment greater than 70 MPa. The high-temperature and high-pressure reactor 5 of this application can support a high-temperature environment of up to 250°C and a high-pressure environment of up to 105 MPa, thus accurately simulating the high-temperature and high-pressure environment of the packer in practical applications.

[0041] The reaction chamber 10 can be mounted on the bottom of the high-temperature and high-pressure reactor 5 via the base 9. The base 9 is arc-shaped, and its outer diameter can be the same as the inner diameter of the high-temperature and high-pressure reactor 5. Furthermore, the sample chamber 1, base 9, piston tube 4, and piston rod 3 of the reaction chamber 10 can all be made of plexiglass.

[0042] like Figure 3 As shown, the electrochemical workstation 20 may include a working electrode 8 and a counter electrode 6 located in the reaction solution, and the electrochemical workstation 20 is used to obtain the resistance value between the working electrode 8 and the counter electrode 6. The working electrode 8 is fixed to the other end of the piston rod 3; that is, the working electrode 8 can be fixed to the tail of the piston rod 3. Once the swellable alloy 2 begins to react and expand, it will push the working electrode 8 to move.

[0043] In one embodiment, the electrochemical workstation 20 may further include a reference electrode 7 located between the working electrode 8 and the counter electrode 6. That is, the counter electrode 6 is fixed to the left end of the chamber of the high-temperature and high-pressure reactor 5, the reference electrode 7 is placed in the middle, and the working electrode 8 is fixed to the right end of the chamber, so that the three electrodes (reference electrode, working electrode, and counter electrode) are kept on the same plane, thereby completing the construction of the three-electrode system.

[0044] In one embodiment, the materials for the counter electrode and the working electrode can be platinum (Pt) or carbon materials. The material for the reference electrode can be saturated calomel or Ag / AgCl. Furthermore, the reaction solution can be a chloride ion salt solution or other suitable halide ion salt solution to react with the swellable alloy, such as KCl solution or NaCl solution. The chloride ion concentration in the above solution can be selected according to actual needs, for example, within the range of 2-10 wt.%. In one embodiment, a 3.5 wt.% KCl solution can be selected as the reaction solution.

[0045] In one embodiment, the processor 30 can also be used to: determine the expansion rate of the swellable alloy based on a first fitting coefficient and a second fitting coefficient between the test distance between the working electrode and the counter electrode and the test resistance of the reaction solution, and the measured resistance value of the reaction solution between the working electrode and the counter electrode.

[0046] Specifically, electrochemical impedance spectroscopy can be used to obtain a first and a second fitting coefficient between the test distance between the working electrode and the counter electrode and the test resistance of the reaction solution. For example, the first and second fitting coefficients can be determined in the following manner:

[0047] 1) Adjust the distance between the working electrode and the counter electrode multiple times to obtain multiple test distances;

[0048] 2) Obtain the resistance values ​​of the reaction solution at set temperature and pressure after each distance adjustment using an electrochemical workstation to obtain multiple test resistance values; and

[0049] 3) Perform linear fitting on multiple test distances and multiple test resistance values ​​to determine the first fitting coefficient and the second fitting coefficient.

[0050] Specifically, under constant temperature, pressure, and solution conditions (salt type, solution concentration), the test resistance R of the solution is first measured using electrochemical impedance spectroscopy by actively changing the test distance x between the working electrode and the counter electrode. Then, the relationship between the test resistance R and the test distance x is obtained through linear fitting to determine the values ​​of the first fitting coefficient a and the second fitting coefficient b.

[0051] x = aR + b, (1)

[0052] Then, a swellable alloy sample is placed in the reaction chamber for a swelling reaction. Specific dimensions are indicated below. Figure 3 That is, the length of the reaction chamber containing the swellable alloy is L0. After the reaction, due to the expansion of the swellable alloy, the piston rod pushes outward, and the length of the reaction chamber becomes L1. The expansion of the swellable alloy will cause the distance x between the electrodes to change. Let the initial distance be x0, the distance between the bottom of the reaction chamber and the counter electrode be x2, and the size of the swellable alloy sample be s0. Therefore, the real-time expansion rate δ of the swellable alloy material can be derived as:

[0053]

[0054] x2 = L1 + x, (3)

[0055] From (1)-(3), we can obtain that

[0056]

[0057] Therefore, in this embodiment, the processor 30 may also include the above-described derivation formula to perform the following function: based on the first fitting coefficient a and the second fitting coefficient b between the test distance between the working electrode and the counter electrode and the test resistance of the reaction solution, and the measured resistance value R of the reaction solution between the working electrode and the counter electrode, the expansion rate δ of the swellable alloy is determined by the following formula:

[0058]

[0059] Where x2 is the distance between the counter electrode and the tail of the reaction chamber, L0 is the initial size of the reaction chamber, and s0 is the initial size of the swellable alloy.

[0060] Alternatively, equation (5) can be transformed into:

[0061] δ=m-nR, where,

[0062] It is evident that the electrochemical workstation can perform electrochemical impedance spectroscopy measurements on the three-electrode system inside the reactor in a timely manner to determine the first fitting coefficient a and the second fitting coefficient b between the distance between the working electrode and the counter electrode and the resistance of the reaction solution. Then, based on the equivalent circuit, the resistance value R of the reaction solution between the working electrode and the counter electrode at different reaction time periods can be obtained, and the real-time expansion rate δ of the swellable alloy can be obtained through the above equation (5).

[0063] The structural composition and method of the present invention will be further described below with reference to the accompanying drawings.

[0064] In one embodiment, the sample chamber is a cylinder with a length of approximately 22 mm and an outer diameter of 18 mm. Several small holes with a diameter of 0.7 mm are provided around the sample chamber to allow the reaction solution to continuously enter and react with the swellable alloy material. The internal sample has an outer diameter of 6 mm and a length of 10 mm (s0). The piston tube is 58 mm long, with an outer diameter of 14 mm and an inner diameter of 6 mm; the piston rod is 60 mm long, with a 16 mm diameter disc at the left end for placing the working electrode, thus obtaining L0 = 74 mm. Additionally, a three-electrode system is constructed in a 3.5 wt.% KCl solution (refer to...). Figure 3 The arrangement uses Pt as the working electrode and counter electrode, and a saturated calomel electrode as the reference electrode. The reference electrode is placed between the working electrode and the counter electrode, with x2 being 154 mm.

[0065] Then, the distance between the two platinum electrodes was controlled at 6.5 cm, 7 cm, 7.5 cm, and 8 cm, respectively, and the electrochemical impedance spectroscopy was measured as a function of distance. Figures 4a-4b As shown. (Through) Figure 5 By fitting the effective circuit diagram shown, the relationship between the platinum electrode spacing and the resistance can be obtained:

[0066] x = 0.012R + 0.0416 (6)

[0067] Then, based on the above x2 = 0.154m, L0 = 0.074m, and s0 = 0.01m, substituting these parameters into equation (5) yields:

[0068] δ=3.84-1.2R (7)

[0069] Next, the reaction chamber containing the swellable alloy sample was installed at the bottom of the solution tank, and a 3.5 wt.% KCl solution was injected into the reaction vessel. Figures 6a-6b As shown, electrochemical impedance spectroscopy can be measured every 12 hours at room temperature and pressure. Figure 7As shown, the solution resistance at each time point can be obtained, and the expansion rate of the swellable alloy at different time points can be calculated according to equation (7). If the electrochemical impedance R at different time points is measured in real time, the change of the expansion rate δ of the swellable alloy under different pressure and temperature conditions can be reflected in real time.

[0070] The device for testing the expansion rate of swellable alloys provided by this invention can meet the requirement of real-time monitoring of the expansion coefficient of swellable alloys under high temperature and high pressure environments. Simultaneously, the process is simple and efficient, using only electrochemical impedance spectroscopy combined with a high-temperature and high-pressure reactor to determine the expansion coefficient of swellable alloys under different temperature and pressure environments. After the swellable alloy reacts with the solution, its volume increases significantly. The reaction products of the swellable alloy can only move in a specific direction within the designed reaction device, thereby driving the working electrode at the tail of the piston rod to move. By establishing the relationship between the solution resistance and the distance between the working electrode and the control electrode, the expansion rate of the swellable alloy under high temperature and high pressure environments can be characterized in real time.

[0071] On the other hand, the present invention also provides a method 200 for testing the expansion rate of a swellable alloy, such as... Figure 8 As shown, the test method 200 may include steps S210-S230.

[0072] Step S210: Place the swellable alloy in the hollow cavity of the sample chamber, bring one end of the piston rod into contact with the swellable alloy, and fix the counter electrode of the electrochemical workstation to the other end of the piston rod.

[0073] Step S220: Obtain the resistance value between the working electrode and the counter electrode of the electrochemical workstation, wherein the counter electrode and the working electrode are located in a reaction solution, and the reaction solution has a set temperature and a set pressure; and

[0074] Step S230: Determine the expansion rate of the swellable alloy based on the obtained resistance value.

[0075] Specifically, prior to step S220, the test method 200 may further include:

[0076] Step S215: Determine the first fitting coefficient and the second fitting coefficient between the test distance between the working electrode and the counter electrode and the test resistance of the reaction solution.

[0077] Therefore, in this embodiment, step S230 may further include: determining the expansion rate of the swellable alloy based on the first and second fitting coefficients between the test distance between the working electrode and the counter electrode and the test resistance of the reaction solution, and the measured resistance value of the reaction solution between the working electrode and the counter electrode.

[0078] Specifically, electrochemical impedance spectroscopy can be used to obtain a first and a second fitting coefficient between the test distance between the working electrode and the counter electrode and the test resistance of the reaction solution. For example, the first and second fitting coefficients can be determined in the following manner:

[0079] 1) Adjust the distance between the working electrode and the counter electrode multiple times to obtain multiple test distances;

[0080] 2) Obtain the resistance values ​​of the reaction solution at set temperature and pressure after each distance adjustment using an electrochemical workstation to obtain multiple test resistance values; and

[0081] 3) Perform linear fitting on multiple test distances and multiple test resistance values ​​to determine the first fitting coefficient and the second fitting coefficient.

[0082] Specifically, under constant temperature, pressure, and solution conditions, the test resistance R of the solution can be measured first by actively changing the test distance x between the working electrode and the counter electrode using electrochemical impedance spectroscopy. Then, the relationship between the test resistance R and the test distance x can be obtained through linear fitting to determine the values ​​of the first fitting coefficient a and the second fitting coefficient b.

[0083] x = aR + b, (1)

[0084] Then, a swellable alloy sample is placed in the reaction chamber for a swelling reaction. Specific dimensions are indicated below. Figure 3 That is, the length of the reaction chamber containing the swellable alloy is L0. After the reaction, due to the expansion of the swellable alloy, the piston rod pushes outward, and the length of the reaction chamber becomes L1. The expansion of the swellable alloy will cause the distance x between the electrodes to change. Let the initial distance be x0, the distance between the bottom of the reaction chamber and the counter electrode be x2, and the size of the swellable alloy sample be s0. Therefore, the real-time expansion rate δ of the swellable alloy material can be derived as:

[0085]

[0086] x2 = L1 + x, (3)

[0087] From (1)-(3), we can obtain that

[0088]

[0089] Therefore, in this embodiment, the expansion rate δ of the swellable alloy can be determined by the following formula based on the first fitting coefficient a and the second fitting coefficient b between the test distance between the working electrode and the counter electrode and the test resistance of the reaction solution, and the measured resistance value R of the reaction solution between the working electrode and the counter electrode:

[0090]

[0091] Where x2 is the distance between the counter electrode and the tail of the reaction chamber, L0 is the initial size of the reaction chamber, and s0 is the initial size of the swellable alloy.

[0092] Alternatively, equation (5) can be transformed into:

[0093] δ=m-nR, where,

[0094] It is evident that the electrochemical workstation can perform electrochemical impedance spectroscopy measurements on the three-electrode system inside the reactor in a timely manner to determine the first fitting coefficient a and the second fitting coefficient b between the distance between the working electrode and the counter electrode and the resistance of the reaction solution. Then, based on the equivalent circuit, the resistance value R of the reaction solution between the working electrode and the counter electrode at different reaction time periods can be obtained, and the real-time expansion rate δ of the swellable alloy can be obtained through the above equation (5).

[0095] The method for testing the expansion rate of swellable alloys provided by this invention can meet the requirements for real-time monitoring of the expansion coefficient of swellable alloys under high temperature and high pressure environments. Simultaneously, the process is simple and efficient, using only electrochemical impedance spectroscopy combined with a high-temperature and high-pressure reactor to determine the expansion coefficient of swellable alloys under different temperature and pressure conditions. After the swellable alloy reacts with the solution, its volume increases significantly. The reaction products of the swellable alloy can only move in a specific direction within the designed reaction apparatus, thereby driving the working electrode at the tail of the piston rod to move. By establishing the relationship between the solution resistance and the distance between the working electrode and the control electrode, the expansion rate of the swellable alloy under high temperature and high pressure environments can be characterized in real time.

[0096] Other beneficial effects of this method for testing the expansion rate of swellable alloys can be found in the description of the beneficial effects of the apparatus for testing the expansion rate of swellable alloys described above, and will not be repeated here.

[0097] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0098] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A testing device for the expansion rate of a swellable alloy, characterized in that, The testing apparatus includes: The reaction chamber includes a sample chamber and a piston rod. The sample chamber has a hollow cavity for accommodating the swellable alloy. One end of the piston rod is in contact with the swellable alloy and moves in response to the expansion of the swellable alloy. An electrochemical workstation includes a counter electrode and a working electrode located in a reaction solution. The working electrode is fixed to the other end of a piston rod. The electrochemical workstation is used to acquire the resistance value between the working electrode and the counter electrode. The reaction solution has a set temperature and a set pressure. The processor is used to determine the expansion rate of the swellable alloy based on the resistance value obtained from the electrochemical workstation.

2. The testing apparatus according to claim 1, characterized in that, The reaction chamber also includes a piston tube with a hollow cavity for accommodating the piston rod and guiding its movement. The hollow cavity cross-section of the sample chamber, the hollow cavity cross-section of the piston tube, and the cross-section of the piston rod have the same shape and size.

3. The testing apparatus according to claim 2, characterized in that, One end of the sample chamber is open, and the piston tube is connected to one end of the sample chamber opening by a thread. The cross-section of the hollow cavity of the sample chamber, the cross-section of the hollow cavity of the piston tube, and the cross-section of the piston rod are all circular, elliptical, triangular, quadrilateral, or hexagonal.

4. The testing apparatus according to claim 1, characterized in that, The sample chamber includes multiple liquid inlets, which are distributed on the outer surface of one end of the sample chamber. The multiple liquid inlets are multiple holes with an inner diameter smaller than a set value.

5. The testing apparatus according to claim 1, characterized in that, The electrochemical workstation also includes a reference electrode located between the working electrode and the counter electrode, wherein the reference electrode, the working electrode, and the counter electrode are located in the same plane.

6. The testing apparatus according to claim 5, characterized in that, The materials of the counter electrode and the working electrode are platinum or carbon, and the material of the reference electrode is saturated calomel or Ag / AgCl; The reaction solution is a halide ion salt solution, preferably a KCl solution or a NaCl solution.

7. The testing apparatus according to claim 1, characterized in that, The processor is further configured to determine the expansion rate of the swellable alloy based on a first fitting coefficient and a second fitting coefficient between the test distance between the working electrode and the counter electrode and the test resistance of the reaction solution, and the measured resistance value of the reaction solution between the working electrode and the counter electrode.

8. The testing apparatus according to claim 7, characterized in that, The first fitting coefficient and the second fitting coefficient are determined in the following manner: The distance between the working electrode and the counter electrode is adjusted multiple times to obtain multiple test distances; The electrochemical workstation is used to obtain the resistance value of the reaction solution after each distance adjustment at the set temperature and the set pressure, so as to obtain multiple test resistance values. as well as Linear fitting is performed on the plurality of test distances and the plurality of test resistance values ​​to determine the first fitting coefficient and the second fitting coefficient.

9. The testing apparatus according to claim 7 or 8, characterized in that, The processor is further configured to determine the expansion rate δ of the swellable alloy based on a first fitting coefficient a and a second fitting coefficient b between the test distance between the working electrode and the counter electrode and the test resistance of the reaction solution, and the measured resistance value R of the reaction solution between the working electrode and the counter electrode, using the following formula: Where x2 is the distance between the counter electrode and the tail of the reaction chamber, L0 is the initial size of the reaction chamber, and s0 is the initial size of the swellable alloy.

10. A method for testing the expansion rate of a swellable alloy, characterized in that, The testing method includes: The swellable alloy is placed in the hollow cavity of the sample chamber, one end of the piston rod is brought into contact with the swellable alloy, and the working electrode of the electrochemical workstation is fixed to the other end of the piston rod. Obtain the resistance value between the counter electrode and the working electrode of the electrochemical workstation, wherein the counter electrode and the working electrode are located in a reaction solution having a set temperature and a set pressure; and The expansion rate of the swellable alloy is determined based on the obtained resistance value.

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