Annular pressure relief device and method

Abstract

The invention relates to the technical field of natural gas development, and particularly discloses an annulus pressure relief device and method.The annulus pressure relief device comprises a pump drawing system, a pressure relief system and a pressure relief system, the storage tank is used for storing gas or protection liquid and is connected with the swabbing pump through a pipeline, a control valve is arranged on the pipeline, the three-way valve is arranged at the rear end of the swabbing pump, one end of the liquid replacing pipe and one end of the liquid supplementing pipe are connected with two ports of the three-way valve respectively, and the other ends of the liquid replacing pipe and the liquid supplementing pipe extend into an annulus; the pressure relief system comprises a pressure relief pipe, one end of the pressure relief pipe extends into the annulus, and the other end of the pressure relief pipe extends out of the annulus and is arranged on the ground; a pressure relief valve and a flange type parallel gate valve are arranged on the pressure relief pipe; and the control system comprises a pressure sensor, a pressure difference detection unit and a controller, the pressure sensor is used for detecting the annular pressure, and the pressure difference detection unit is used for detecting the pressure difference between the pumping system and the pressure relief system. By means of the annular pressure relief device, annular pressure relief can be achieved, and annular protection liquid can be sampled and replaced.

Description

Technical Field

[0001] The present invention relates to the technical field of natural gas development, and particularly relates to an annulus pressure relief device and method. Background Art

[0002] At present, with the increasing demand for oil and gas and the continuous deepening of exploration and development work, the downhole geological conditions and wellbore structures are becoming more and more complex, and the annulus pressure anomaly problem is becoming more and more prominent.

[0003] On the one hand, for gas wells, in some abnormal situations, if the packer has poor sealing effect or the oil casing and tubing are damaged due to corrosion, it may cause the leakage of annulus protection fluid and the intrusion of corrosive gas into the annulus, which will further cause the annulus pressure to rise, leading to serious accidents such as wellhead lifting. The intrusion of gas and other impurities will also affect the performance of the annulus protection fluid and reduce its protection effect, bringing potential safety hazards to the safe production of gas wells; on the other hand, for oil wells, if the packer has poor sealing effect or the oil casing and tubing are damaged due to corrosion, it may cause the leakage of annulus protection fluid, which will further cause insufficient annulus pressure between the oil casing and tubing, resulting in deformation and damage of the oil casing and tubing under large pressure.

[0004] Therefore, it is necessary to detect the annulus pressure and dispose of the gas wells with abnormal annulus pressure in advance by relieving the pressure. Summary of the Invention

[0005] The purpose of the present invention is to provide an annulus pressure relief device and method, which can not only achieve annulus pressure relief, but also sample and replace the annulus protection fluid.

[0006] The present invention is realized by the following technical solutions:

[0007] An annulus pressure relief device includes:

[0008] A pumping system for realizing the circulation of annulus protection fluid and supplementing annulus protection fluid into the annulus, including a storage tank, a pumping pump, a three-way valve, a displacement pipe and a replenishment pipe; the storage tank is used for storing gas or protection fluid, and is connected to the pumping pump through a pipeline, and a control valve is arranged on this pipeline. The three-way valve is arranged at the rear end of the pumping pump. One end of the displacement pipe and the replenishment pipe are respectively connected to two ports of the three-way valve, and the other ends both extend into the annulus;

[0009] A pressure relief system for discharging gas or annulus protection fluid in the annulus to realize annulus pressure relief, including a pressure relief pipe. One end of the pressure relief pipe extends into the annulus, and the other end extends out of the annulus and is placed on the ground; a pressure relief valve and a flanged parallel gate valve are arranged on the pressure relief pipe;

[0010] The control system includes a pressure sensor, a differential pressure detection unit, and a controller. The pressure sensor is used to detect the annulus pressure, and the differential pressure detection unit is used to detect the differential pressure between the pumping system and the pressure relief system. The pressure sensor, the differential pressure detection unit, the pressure relief valve, the pumping pump, and the control valve are all communicatively connected to the controller.

[0011] There is a differential pressure between the pumping system and the pressure relief system in the present invention. This pressure difference, when superimposed with the liquid column pressure of the annulus protection liquid, can balance the annulus pressure, thereby reducing the density of the annulus protection liquid and lowering the economic cost.

[0012] The present invention can, according to the annulus pressure detected in real time by the pressure sensor, when the annulus pressure reaches the set threshold, the controller controls the pressure relief valve to open for pressure relief.

[0013] That is, the pressure relief system in the present invention can achieve pressure relief for the annulus. The pumping system can achieve the circulation of the annulus protection liquid and replenish the annulus protection liquid into the annulus for sampling and replacing the protection liquid. The control system realizes the automatic control of the entire annulus pressure relief device.

[0014] In summary, the annulus pressure relief device in the present invention can not only achieve annulus pressure relief, but also sample and replace the annulus protection liquid.

[0015] Further, the control system further includes a liquid level gauge. The liquid level gauge is used to detect the liquid level in the annulus and transmit the detected liquid level to the controller. The pressure sensor and the liquid level gauge form a double insurance, respectively judging whether to perform operations such as pressure relief or liquid replenishment based on the pressure and the liquid level height in the annulus.

[0016] Further, the storage tank includes a gas storage tank and a liquid storage tank. The gas storage tank and the liquid storage tank store gas and protection liquid respectively. The gas storage tank and the liquid storage tank are respectively connected to the pumping pump through pipelines.

[0017] Further, it further includes a fixing hoop. Both the pressure relief pipe and the liquid replacement pipe are tied to the tubing through the fixing hoop.

[0018] Further, one end of the pressure relief pipe extending into the annulus is connected with a filtering structure through a taper joint.

[0019] Further, the differential pressure detection unit includes a first pressure gauge and a second pressure gauge. The first pressure gauge and the second pressure gauge are respectively used to detect the pressures of the pumping system and the pressure relief system and transmit the detected pressures to the controller.

[0020] Further, the storage tank, the pumping pump, the three-way valve, the pressure relief valve, and the flanged parallel gate valve are all placed on the ground. Shifting the control of the annulus pressure above the wellhead is convenient for control and convenient for sampling and replacing the annulus protection liquid.

[0021] Pressure relief method based on an annulus pressure relief device, comprising the following steps:

[0022] S1. After well completion, calculate the annulus pressure, calculate the density of the annulus protection fluid, maintain a stable pressure difference within a certain range between the pumping system and the pressure relief system, and balance the annulus pressure by superimposing the hydrostatic pressure of the annulus protection fluid;

[0023] S2. The pressure sensor detects the annulus pressure in real time and transmits the detected pressure to the controller. When the pressure in the annulus exceeds the set threshold, the controller controls the pressure relief valve to open, and the protection fluid or gas in the annulus is discharged from the annulus through the pressure relief pipe;

[0024] S3. When the liquid level in the annulus drops to the set height or the pressure in the annulus decreases to a certain extent, the pressure difference between the pumping system and the pressure relief system will also decrease accordingly. At this time, the pumping pump pumps gas or protection fluid from the storage tank to supplement this pressure drop, so as to supplement the pressure difference between the pumping system and the pressure relief system, and at the same time stabilize the pressure in the annulus;

[0025] S4. Obtain the pressure difference between the pumping system and the pressure relief system through the differential pressure detection unit. When the pressure relief system fails to work properly, manually open the flanged parallel gate valve for pressure relief.

[0026] Sampling method based on an annulus pressure relief device, comprising the following steps:

[0027] Step 1. Manually close the flanged parallel gate valve before sampling to make the pressure relief system in a closed state; close the control valve between the storage tank and the pumping pump;

[0028] Step 2. Start the pumping pump to circulate the annulus protection fluid in the annulus. The annulus protection fluid is circulated out of the annulus through the displacement fluid pipe and enters the pumping pump, and then re-circulates into the annulus from the pumping pump through the liquid supply pipe; after the circulation is completed, stop the operation of the pumping system, and take an appropriate amount of annulus protection fluid from the pumping system for detection;

[0029] Step 3. After sampling, open the flanged parallel gate valve to ensure that the pressure difference between the pumping system and the pressure relief system is stable within a certain range.

[0030] Replacement method based on an annulus pressure relief device, comprising the following steps:

[0031] Step A. Circulate the annulus protection fluid in the annulus:

[0032] Step A1. Manually close the flanged parallel gate valve before sampling to make the pressure relief system in a closed state; close the control valve between the storage tank and the pumping pump;

[0033] Step A2. Start the pumping pump to circulate the annulus protection fluid in the annulus. The annulus protection fluid is circulated out of the annulus through the displacement fluid pipe and enters the pumping pump, and then re-circulates into the annulus from the pumping pump through the liquid supply pipe;

[0034] Step B: Replace the protective fluid:

[0035] Open the control valve between the storage tank and the pumping pump; inject a predetermined volume of new annulus protective fluid into the annulus through the liquid supply pipe, and discharge the original annulus protective fluid from the annulus through the displacement pipe; during the displacement process, ensure the stability of the pressure difference between the pumping system and the pressure relief system.

[0036] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0037] 1. The pressure relief system of the present invention can achieve pressure relief of the annulus. The pumping system can realize the circulation of the annulus protective fluid and supplement the annulus protective fluid into the annulus for sampling and replacing the protective fluid. The control system realizes the automatic control of the entire annulus pressure relief device; that is, the annulus pressure relief device of the present invention can not only achieve annulus pressure relief, but also sample and replace the annulus protective fluid.

[0038] 2. The present invention places the control of the annulus pressure on the ground, stabilizes the annulus pressure by setting a reasonable pressure difference, reduces the density of the annulus protective fluid, and the sampling detection and replacement of the annulus protective fluid can be realized on the ground, making the operation simpler.

[0039] 3. The present invention forms a set of safe and independent pipeline systems. This system can be operated independently, the construction process is simple and convenient, and it does not affect the production and other operations of the well. Description of the Drawings

[0040] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, form a part of this application, and do not limit the embodiments of the present invention. In the drawings:

[0041] Figure 1 It is a schematic structural diagram of the annulus pressure relief device of the present invention.

[0042] Marks in the drawings and corresponding component names:

[0043] 1 - storage tank; 2 - pumping pump; 3 - first pressure gauge; 4 - three-way valve; 5 - pressure relief valve; 6 - flanged parallel gate valve; 7 - displacement pipe; 8 - liquid supply pipe; 9 - pressure sensor; 10 - liquid level gauge; 11 - casing; 12 - tubing; 13 - packer; 14 - pressure relief pipe; 15 - fixing hoop; 16 - taper joint; 17 - filtering structure; 18 - annulus protective fluid. Detailed Embodiments

[0044] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in combination with embodiments and drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and do not limit the present invention.

[0045] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well-known structures, materials, or methods have not been specifically described to avoid obscuring aspects of the present invention.

[0046] Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality of" means two or more unless specifically and explicitly defined otherwise.

[0047] Embodiment 1:

[0048] As Figure 1 shown, an annulus pressure relief device includes:

[0049] A pumping system for circulating the annulus protection fluid 18 and replenishing the annulus with the annulus protection fluid 18, including a storage tank 1, a pumping pump 2, a three-way valve 4, a displacement pipe 7, and a replenishment pipe 8; the storage tank 1 is used for storing gas or protection fluid, and is connected to the pumping pump 2 through a pipeline to provide a pressure source for the pumping system, and a control valve is provided on this pipeline. Specifically, the storage tank 1 includes a gas storage tank and a liquid storage tank; the gas storage tank and the liquid storage tank store gas and protection fluid respectively, and the gas storage tank and the liquid storage tank are respectively connected to the pumping pump 2 through pipelines; a control valve and a flowmeter are provided on the pipeline between the gas storage tank and the pumping pump 2, and a control valve and a flowmeter are also provided on the pipeline between the liquid storage tank and the pumping pump 2, and the control valve and the flowmeter are communicatively connected to a controller, and the newly injected annulus protection fluid 18 when replacing the annulus protection fluid 18 is controlled through the flowmeter.

[0050] The three-way valve 4 is provided at the rear end of the pumping pump 2, one end of the displacement pipe 7 and the replenishment pipe 8 are respectively connected to two ports of the three-way valve 4, and the other ends both extend into the annulus. Among them, the displacement pipe 7 and the replenishment pipe 8 are connected to the pumping pump 2 through the three-way valve 4 and serve as channels for replenishing and replacing the annulus protection fluid 18. Check valves are provided on both the displacement pipe 7 and the replenishment pipe 8 to enable the annulus protection fluid 18 in the annulus to enter the pumping pump 2 through the displacement pipe 7, and the annulus protection fluid 18 in the pumping pump 2 to return to the annulus between the casing 11 and the tubing 12 through the replenishment pipe 8.

[0051] A pressure relief system for discharging the gas or annulus protection fluid 18 in the annulus to achieve annulus pressure relief, including a pressure relief pipe 14, one end of the pressure relief pipe 14 extends into the annulus, and the other end extends out of the annulus and is placed on the ground; a pressure relief valve 5 and a flanged parallel gate valve 6 are provided on the pressure relief pipe 14.

[0052] A control system includes a pressure sensor 9, a differential pressure detection unit and a controller. The pressure sensor 9 is used to detect the annulus pressure, and the differential pressure detection unit is used to detect the differential pressure between the pumping system and the pressure relief system; the pressure sensor 9, the differential pressure detection unit, the pressure relief valve 5, the pumping pump 2 and the control valve are all communicatively connected to the controller.

[0053] Specifically, the differential pressure detection unit includes a first pressure gauge 3 and a second pressure gauge. The first pressure gauge 3 and the second pressure gauge are respectively used to detect the pressures of the pumping system and the pressure relief system, and transmit the detected pressures to the controller. In a specific case, the first pressure gauge 3 is arranged on the pipeline between the pumping pump 2 and the three-way valve 4, and the second pressure gauge is arranged on the pressure relief pipe 14. The first pressure gauge 3 and the second pressure gauge transmit the detected pressures to the controller, and the differential pressure between the pumping system and the pressure relief system is calculated in the controller. When the differential pressure between the pumping system and the pressure relief system is not within the set range, the differential pressure can be compensated by pressure relief or adding fluid to the annulus. Preferably, a flow meter is provided on the pressure relief pipe 14.

[0054] The pressure sensor 9 can adopt an insertion type pressure sensor. Preferably, a liquid level gauge 10 is further provided in the annulus to detect the liquid level in the annulus and transmit the detected liquid level to the controller. The pressure sensor 9 and the liquid level gauge 10 form a double insurance, and whether to relieve pressure or add fluid, etc. is judged respectively by the pressure in the annulus and the liquid level height in the annulus.

[0055] Preferably, a safety valve is provided on the pressure relief pipe 14. When the pressure in the annulus exceeds the rated threshold of the safety valve, the safety valve automatically opens, and the liquid or gas in the annulus is discharged from the annulus through the pressure relief system.

[0056] Preferably, the storage tank 1, the pumping pump 2, the three-way valve 4, the pressure relief valve 5 and the flanged parallel gate valve 6 are all placed on the ground.

[0057] There is a certain pressure difference between the pumping system and the pressure relief system in this embodiment. This pressure difference and the liquid column pressure of the annulus protection fluid 18 are superimposed to balance the annulus pressure. On the one hand, the density of the annulus protection fluid 18 can be reduced, reducing the economic cost. On the other hand, the control of the annulus pressure is transferred above the wellhead, which is convenient for control and convenient for sampling and replacement of the annulus protection fluid 18.

[0058] In a preferred case, a fixing hoop 15 is further included; both the pressure relief pipe 14 and the fluid replacement pipe 7 are tied to the tubing 12 through the fixing hoop 15 and are lowered into the well together with the tubing 12.

[0059] In a preferred case, one end of the pressure relief pipe 14 extending into the annulus is connected with a filtering structure 17 through a taper joint 16 to prevent impurities from blocking the pressure relief pipe 14.

[0060] Embodiment 2:

[0061] Based on the pressure relief method of the annulus pressure relief device described in Embodiment 1, the method includes the following steps:

[0062] S1. After well completion, calculate the annulus pressure, calculate the density of the annulus protection fluid 18, keep the pressure difference between the pumping system and the pressure relief system stable within a certain range, and balance the annulus pressure by superimposing the liquid column pressure of the annulus protection fluid 18; among them, calculating the annulus pressure and calculating the density of the annulus protection fluid 18 are prior arts and will not be elaborated herein.

[0063] S2. The pressure sensor 9 detects the annulus pressure in real time and transmits the detected pressure to the controller. When the pressure in the annulus exceeds the set threshold, the controller controls the pressure relief valve 5 to open, and the protection fluid or gas in the annulus is discharged from the annulus through the pressure relief pipe 14.

[0064] S3. When the liquid level in the annulus drops to the set height or the pressure in the annulus decreases to a certain extent, the pressure difference between the pumping system and the pressure relief system will also decrease accordingly. At this time, the pumping pump 2 pumps gas or protection fluid from the storage tank 1 to supplement this pressure drop to supplement the pressure difference between the pumping system and the pressure relief system, and at the same time stabilize the pressure in the annulus.

[0065] S4. Obtain the pressure difference between the pumping system and the pressure relief system through the pressure difference detection unit. When the pressure relief system cannot work properly, manually open the flanged parallel gate valve 6 for pressure relief.

[0066] Embodiment 3:

[0067] Based on the sampling method of the annulus pressure relief device described in Embodiment 1, the method includes the following steps:

[0068] Step 1. Manually close the flanged parallel gate valve 6 before sampling to make the pressure relief system in a closed state; close the control valve between the storage tank 1 and the pumping pump 2;

[0069] Step 2: Start the swabbing pump 2 to circulate the annulus protection fluid 18 in the annulus. The annulus protection fluid 18 is circulated out of the annulus through the displacement pipe 7 and enters the swabbing pump 2, and then is recirculated into the annulus from the swabbing pump 2 through the liquid supply pipe 8. During the circulation, observe the pressure difference between the swabbing system and the pressure relief system at any time to prevent damage to the oil casing due to excessive pressure difference. After the circulation is completed, stop the operation of the swabbing system and take an appropriate amount of the annulus protection fluid 18 from the swabbing system for detection. Specifically, a cock can be set on the three-way valve 4. When circulating the annulus protection fluid 18, a sampling bottle can be used, and one end is connected to the cock for sampling.

[0070] Step 3: After sampling, open the flanged parallel gate valve 6 and observe the pressure gauge reading; ensure that the pressure difference between the swabbing system and the pressure relief system is stable within a certain range.

[0071] Example 4:

[0072] Based on the replacement method of the annulus pressure relief device described in Example 1, it includes the following steps:

[0073] Step A: Circulate the annulus protection fluid 18 in the annulus:

[0074] Step A1: Manually close the flanged parallel gate valve 6 before sampling to make the pressure relief system in a closed state; close the control valve between the storage tank 1 and the swabbing pump 2.

[0075] Step A2: Start the swabbing pump 2 to circulate the annulus protection fluid 18 in the annulus. The annulus protection fluid 18 is circulated out of the annulus through the displacement pipe 7 and enters the swabbing pump 2, and then is recirculated into the annulus from the swabbing pump 2 through the liquid supply pipe 8.

[0076] Step B: Replace the protection fluid:

[0077] Open the control valve between the storage tank 1 and the swabbing pump 2; inject a predetermined volume of new annulus protection fluid 18 into the annulus through the liquid supply pipe 8, and discharge the original annulus protection fluid 18 out of the annulus through the displacement pipe 7. During the displacement process, ensure that the pressure difference between the swabbing system and the pressure relief system is stable.

[0078] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0079] It should be noted that the structures, proportions, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the conditions under which the present invention can be implemented. Therefore, they do not have a substantial technical meaning. Any modification of the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope that can be covered by the technical content disclosed in the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle", etc. cited in this specification are only for the convenience of clear description and are not used to limit the scope in which the present invention can be implemented. The change or adjustment of their relative relationship, without substantial change in the technical content, should also be regarded as the scope in which the present invention can be implemented.

Claims

1. A well annulus pressure relief device, characterized in that, it comprises: A pumping system for realizing the circulation of the well annulus protection fluid (18) and supplementing the well annulus protection fluid (18) into the well annulus, including a storage tank (1), a pumping pump (2), a three-way valve (4), a displacement pipe (7) and a liquid supplement pipe (8); the storage tank (1) is used for storing gas or protection fluid, and is connected to the pumping pump (2) through a pipeline, and a control valve is arranged on this pipeline, the three-way valve (4) is arranged at the rear end of the pumping pump (2), one ends of the displacement pipe (7) and the liquid supplement pipe (8) are respectively connected to two ports of the three-way valve (4), and the other ends both extend into the well annulus; A pressure relief system for discharging the gas or the well annulus protection fluid (18) in the well annulus to realize well annulus pressure relief, including a pressure relief pipe (14), one end of the pressure relief pipe (14) extends into the well annulus, and the other end extends out of the well annulus and is placed on the ground; a pressure relief valve (5) and a flanged parallel gate valve (6) are arranged on the pressure relief pipe (14); A control system, including a pressure sensor (9), a differential pressure detection unit and a controller, the pressure sensor (9) is used for detecting the well annulus pressure, and the differential pressure detection unit is used for detecting the differential pressure between the pumping system and the pressure relief system; the pressure sensor (9), the differential pressure detection unit, the pressure relief valve (5), the pumping pump (2) and the control valve are all communicatively connected to the controller.

2. A well annulus pressure relief device according to claim 1, characterized in that, the control system further includes a liquid level gauge (10), and the liquid level gauge (10) is used for detecting the liquid level in the well annulus and transmitting the detected liquid level to the controller.

3. A well annulus pressure relief device according to claim 1, characterized in that, the storage tank (1) includes a gas storage tank and a liquid storage tank; the gas storage tank and the liquid storage tank respectively store gas and protection fluid, and the gas storage tank and the liquid storage tank are respectively connected to the pumping pump (2) through pipelines.

4. A well annulus pressure relief device according to claim 1, characterized in that, it further includes a fixing hoop (15); both the pressure relief pipe (14) and the displacement pipe (7) are tied to the tubing (12) through the fixing hoop (15).

5. A well annulus pressure relief device according to claim 1, characterized in that, one end of the pressure relief pipe (14) extending into the well annulus is connected with a filtering structure (17) through a taper joint (16).

6. A well annulus pressure relief device according to claim 1, characterized in that, the differential pressure detection unit includes a first pressure gauge (3) and a second pressure gauge, and the first pressure gauge (3) and the second pressure gauge are respectively used for detecting the pressures of the pumping system and the pressure relief system and transmitting the detected pressures to the controller.

7. A well annulus pressure relief device according to any one of claims 1-6, characterized in that, the storage tank (1), the pumping pump (2), the three-way valve (4), the pressure relief valve (5) and the flanged parallel gate valve (6) are all placed on the ground.

8. A pressure relief method for the well annulus pressure relief device according to any one of claims 1-7, characterized in that, it includes the following steps: S1. After completion of well completion, calculate the annulus pressure, calculate the density of the annulus protection fluid (18), maintain a stable pressure difference within a certain range between the pumping system and the pressure relief system, and balance the annulus pressure by superimposing the liquid column pressure of the annulus protection fluid (18). S2. The pressure sensor (9) detects the annulus pressure in real time and transmits the detected pressure to the controller. When the pressure in the annulus exceeds the set threshold, the controller controls the pressure relief valve (5) to open, and the protection fluid or gas in the annulus is discharged from the annulus through the pressure relief pipe (14). S3. When the liquid level in the annulus drops to the set height or the pressure in the annulus decreases to a certain extent, the pressure difference between the pumping system and the pressure relief system will also decrease accordingly. At this time, the pumping pump (2) pumps gas or protection fluid from the storage tank (1) to supplement this pressure drop, so as to supplement the pressure difference between the pumping system and the pressure relief system, and at the same time stabilize the pressure in the annulus. S4. Obtain the pressure difference between the pumping system and the pressure relief system through the differential pressure detection unit. When the pressure relief system cannot work properly, manually open the flanged parallel gate valve (6) for pressure relief.

9. A sampling method for the annulus pressure relief device according to any one of claims 1-7, characterized in that, it includes the following steps: Step 1. Manually close the flanged parallel gate valve (6) before sampling to make the pressure relief system in a closed state; close the control valve between the storage tank (1) and the pumping pump (2). Step 2. Start the pumping pump (2) to circulate the annulus protection fluid (18) in the annulus. The annulus protection fluid (18) circulates out of the annulus through the displacement pipe (7) and enters the pumping pump (2), and then recirculates into the annulus from the pumping pump (2) through the replenishment pipe (8); after the circulation ends, stop the operation of the pumping system, and take an appropriate amount of annulus protection fluid (18) from the pumping system for detection. Step 3. After sampling, open the flanged parallel gate valve (6) to ensure that the pressure difference between the pumping system and the pressure relief system is stable within a certain range.

10. A replacement method for the annulus pressure relief device according to any one of claims 1-7, characterized in that, it includes the following steps: Step A. Circulate the annulus protection fluid (18) in the annulus: Step A1. Manually close the flanged parallel gate valve (6) before sampling to make the pressure relief system in a closed state; close the control valve between the storage tank (1) and the pumping pump (2). Step A2. Start the pumping pump (2) to circulate the annulus protection fluid (18) in the annulus. The annulus protection fluid (18) circulates out of the annulus through the displacement pipe (7) and enters the pumping pump (2), and then recirculates into the annulus from the pumping pump (2) through the replenishment pipe (8). Step B. Replace the protection fluid: Open the control valve between the storage tank (1) and the pumping pump (2); inject a predetermined volume of new annulus protection fluid (18) into the annulus through the replenishment pipe (8), and discharge the original annulus protection fluid (18) from the annulus through the displacement pipe (7); during the displacement process, ensure that the pressure difference between the pumping system and the pressure relief system is stable.

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