Pressure relief device and pressure relief pup joint for controlling annulus entrapment pressure

Abstract

The invention provides a pressure relief device and a pressure relief pup joint for controlling annulus entrapment pressure, and relates to the technical field of deepwater oil-gas exploration and developing.The pressure relief device comprises a barrel, a rupture disc, a sliding block and an elastic piece, the barrel is hollow, a containing cavity with the two ends closed is formed in the barrel, the rupture disc is arranged in the containing cavity, and the sliding block is arranged in the containing cavity; the periphery of the rupture disc is in sealed connection with the inner wall of the barrel and divides the containing cavity into a first cavity and a second cavity, a pressure relief inlet communicated with the first cavity is formed in the outer wall of the barrel, the sliding block and the elastic piece are located in the second cavity, and the sliding block is in sliding fit with the inner wall of the barrel and can reciprocate along the axis of the barrel; the two ends of the elastic piece are connected with the sliding block and the end wall of the barrel respectively, a pressure relief outlet is formed in the outer wall of the barrel, and when the elastic piece is not compressed, the sliding block seals the pressure relief outlet. According to the invention, the control of the annulus entrapment pressure can be accurately and safely completed.

Description

Technical Field

[0001] The invention relates to the technical field of deepwater oil and gas exploration and development, and in particular to a pressure relief device and a pressure relief nipple for controlling annular trap pressure. Background Art

[0002] In the past decade, 70% of the world's major oil and gas discoveries came from deepwater, but the large-scale development of deepwater oil and gas resources has been hindered by the harsh wellbore environment and harsh operating environment of deepwater oil and gas wells. Among them, the annular trap pressure problem is one of the main problems threatening wellbore safety in the development of deepwater oil and gas resources. Affected by the immaturity of cementing technology and the uncertainty of formation information, deepwater oil and gas wells will produce multi-layered annular structures. At the same time, during the upward transportation of oil and gas, the heat of the oil and gas fluid will be transferred to the annulus, causing the annular fluid temperature to rise, thereby generating annular trap pressure. When the annular trap pressure is too high, the casing will be squeezed and deformed, causing serious damage to the integrity of the wellbore. However, unlike onshore oil and gas wells, the wellhead device of deepwater oil and gas wells is designed to be completely closed, and it is impossible to form a pressure relief channel to release the annular trap pressure, which further increases the risk of annular trap pressure. Therefore, conducting research on the control of annular trap pressure in deepwater wells is an important part of ensuring the long-term safe and stable production of deepwater oil and gas wells.

[0003] Installing an annular trap pressure relief device on the casing or casing nipple is one of the effective solutions. As early as 2003, Total first applied rupture discs to pressure control in offshore oil and gas fields. Rupture disc technology is still an important means of annular trap pressure control in offshore oil and gas development. First, the predetermined rupture pressure is designed according to the site requirements, the size and shape of the rupture disc, the thickness and strength of the disc material, and the weak point line formed in the disc. When the annular trap pressure in the casing reaches the predetermined value, the rupture disc ruptures to release the pressure, thereby reducing the annular trap pressure. However, the traditional method of using rupture discs to release annular trap pressure has a narrow pressure relief range, although the pressure control accuracy is high, and it can only work when the specified pressure value is reached. Moreover, when the rupture disc is working, it will fail, destroying the integrity of the wellbore. In addition to rupture disks, there are also automatic pressure relief devices such as downhole casing pressure relief nipples in the field of deepwater annular trap pressure relief. They usually use the reciprocating motion of components such as sliders, springs or pistons to achieve the purpose of automatic pressure relief. However, due to the harsh operating environment of deepwater wells, these components are very easy to fail, increasing the risk of threatening the safety of the wellbore, and therefore have not been widely used.

[0004] In view of this, the inventor has designed a pressure relief device and a pressure relief nipple for controlling the annular trap pressure based on many years of production design experience in this field and related fields and through repeated experiments, in order to solve the problems existing in the prior art. Summary of the invention

[0005] The object of the present invention is to provide a pressure relief device and a pressure relief nipple for controlling the annular trap pressure, which can accurately and safely complete the control of the annular trap pressure.

[0006] To achieve the above-mentioned purpose, the present invention proposes a pressure relief device for controlling the closed annulus pressure, wherein the pressure relief device comprises a cylinder, a rupture disk, a slider and an elastic member, the cylinder is hollow inside and forms a accommodating chamber with two closed ends, the rupture disk is arranged in the accommodating chamber, the periphery of the rupture disk is sealed and connected with the inner wall of the cylinder and divides the accommodating chamber into a first chamber and a second chamber, a pressure relief inlet connected to the first chamber is opened on the outer wall of the cylinder, the slider and the elastic member are located in the second chamber, the slider is slidably matched with the inner wall of the cylinder and can reciprocate along the axis of the cylinder, the two ends of the elastic member are respectively connected with the slider and the end wall of the cylinder, a pressure relief outlet is opened on the outer wall of the cylinder, when the elastic member is not compressed, the slider closes the pressure relief outlet, and the pressure relief device releases the pressure in the annulus outside the cylinder to the annulus inside the cylinder according to the pressure.

[0007] The present invention also proposes a pressure relief nipple for controlling annular closure pressure, wherein the pressure relief nipple includes a nipple body and at least one pressure relief device for controlling annular closure pressure as described above, which is installed on the nipple body, the nipple body has an axially through inner cavity, the cylinder is fixedly connected to the outer side wall of the nipple body, a through hole is provided on the side wall of the nipple body and is aligned with the pressure relief outlet, and the pressure relief inlet is provided on the side of the cylinder facing away from the nipple body.

[0008] Compared with the prior art, the present invention has the following characteristics and advantages:

[0009] The present invention proposes a pressure relief device and a pressure relief nipple for controlling the annular closure pressure. A rupture disk is arranged in the cylinder of the pressure relief device. Only when the annular closure pressure rises to a specified value and destroys the rupture disk, the annular fluid will enter the second chamber from the first chamber through the rupture disk and push the slider to squeeze the elastic member to open the pressure relief outlet, so that the fluid can eventually flow out of the pressure relief outlet to achieve pressure relief. Due to the presence of the rupture disk, the slider and the elastic member will not be exposed to the harsh deep-water operating environment too early, providing a good protection for the slider and the elastic member. At the same time, when the annular closure pressure is released to a pressure that is not enough to threaten the safety of the wellbore, the compressed elastic member recovers, pushing the slider to reset and block the pressure relief outlet, thereby ensuring the integrity of the wellbore. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings described herein are only for explanation purposes and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the various components in the figures are only schematic, used to help understand the present invention, and are not specifically limited to the shapes and proportional dimensions of the various components of the present invention. Those skilled in the art can select various possible shapes and proportional dimensions to implement the present invention according to the teachings of the present invention.

[0011] Figure 1 This is an appearance diagram of a pressure relief device for controlling annular trap pressure proposed by the present invention;

[0012] Figure 2 This is a working schematic diagram of the pressure relief device of the present invention (the rupture disk is intact);

[0013] Figure 3 It is a working schematic diagram of the pressure relief device in the present invention (rupture disk is broken);

[0014] Figure 4 It is a structural schematic diagram of the pressure relief device in the present invention;

[0015] Figure 5 It is a schematic diagram of the structure of the rupture disk in the present invention;

[0016] Figure 6 This is the appearance diagram of the pressure relief nipple in the present invention.

[0017] Description of Reference Numerals

[0018] 100. Pressure relief device; 10. Cylinder;

[0019] 11. First chamber; 12. Second chamber;

[0020] 13. Pressure relief inlet; 14. Pressure relief outlet;

[0021] 20. rupture disc; 21. rupture disc valve body;

[0022] 22. Bursting disc; 23. Support ring;

[0023] 30. Slider; 40. Elastic member;

[0024] 50. One-way valve; 60. Spring seat;

[0025] 200. Pressure relief nipple; 210. Nipple body;

[0026] 220. Through hole. DETAILED DESCRIPTION

[0027] The details of the present invention can be more clearly understood with reference to the accompanying drawings and the description of the specific embodiments of the present invention. However, the specific embodiments of the present invention described herein are only used for the purpose of explaining the present invention and cannot be understood as limiting the present invention in any way. Under the guidance of the present invention, technicians can conceive of any possible variations based on the present invention, which should all be considered to belong to the scope of the present invention.

[0028] like Figures 1 to 5 As shown, the present invention proposes a pressure relief device 100 for controlling the closed annulus pressure, the pressure relief device 100 includes a cylinder 10, a rupture disk 20, a slider 30 and an elastic member 40. The cylinder 10 is hollow inside and forms a accommodating chamber with two ends closed. The rupture disk 20 is arranged in the accommodating chamber. The outer edge of the rupture disk 20 in the circumferential direction is sealed and connected to the inner wall of the cylinder 10 and divides the accommodating chamber into a first chamber 11 and a second chamber 12. A pressure relief inlet 13 connected to the first chamber 11 is opened on the outer wall of the cylinder 10. The slider 30 and the elastic member 40 are located in the second chamber. The slider 30 is slidably matched with the inner wall of the cylinder 10 and can reciprocate along the axis of the cylinder 10. The two ends of the elastic member 40 are respectively connected to the slider 30 and the end wall of the cylinder 10. A pressure relief outlet 14 is opened on the outer wall of the cylinder 10. When the elastic member 40 is not compressed, the slider 30 closes the pressure relief outlet 14.

[0029] The present invention also provides a pressure relief nipple 200 for controlling the annular trap pressure. Figure 6 As shown, the pressure relief nipple 200 includes a nipple body 210 and at least one pressure relief device 100 as described above installed on the nipple body 210, the nipple body 210 has an axially through inner cavity, the cylinder 10 of the pressure relief device 100 is fixedly connected to the outer wall of the nipple body 210, and a through hole 220 is provided on the side wall of the nipple body 210 to match the pressure relief outlet 14, and the pressure relief inlet 13 is provided on the side of the cylinder 10 facing away from the nipple body 210.

[0030] The present invention proposes a pressure relief device 100 and a pressure relief nipple 200 for controlling annular space closure pressure. The pressure relief device 100 is installed on the outer wall of a nipple body 210 of the pressure relief nipple 200. The nipple body 210 is connected to the casing. The annular space closure pressure in the annulus between the casing and the wellbore can be discharged into the casing through the pressure relief device 100, thereby avoiding damage to the wellbore or casing caused by excessive annular space closure pressure.

[0031] The pressure relief device 100 and the pressure relief nipple 200 for controlling the annular closure pressure proposed by the present invention are provided with a rupture disk 20 in the cylinder 10 of the pressure relief device 100. Only when the annular closure pressure rises to a specified value and the rupture disk 20 is squeezed out, the annular fluid will enter the second chamber 12 from the first chamber 11 through the rupture disk 20 and push the slider 30 to squeeze the elastic member 40 to open the pressure relief outlet 14, so that the fluid can finally flow out from the pressure relief outlet 14 to achieve pressure relief. Due to the presence of the rupture disk 20, the slider 30 and the elastic member 40 will not be exposed to the harsh deep-water operating environment too early, providing a good protection for the slider and the elastic member 40. At the same time, when the annular closure pressure is released to a pressure that is not enough to threaten the safety of the wellbore, the compressed elastic member 40 recovers, pushing the slider 30 to reset and block the pressure relief outlet 14, thereby ensuring the integrity of the wellbore.

[0032] The pressure relief device 100 and the pressure relief nipple 200 for controlling the annular closure pressure proposed in the present invention will release pressure only when the pressure is greater than the pressure of the rupture disk, and can accurately and safely control the annular closure pressure.

[0033] The pressure relief device 100 for controlling the annular trap pressure proposed by the present invention is connected to the casing through the pressure relief nipple 200, which can accurately and safely complete the control of the annular trap pressure, ensure the integrity of the wellbore, and protect the safety of the wellbore. At the same time, the pressure relief nipple 200 can be conveniently connected to the casing, and has the advantage of simple and convenient installation.

[0034] In the present invention, an elastic member-slider combination design is adopted, and the purpose of automatic pressure relief is achieved by compressing the combined design of the elastic member 40 and the slider 30, and the slider 30 can well isolate the elastic member 40 from the annular space fluid, ensuring that the elastic member 40 can work for a long time, efficiently and safely.

[0035] In an optional embodiment of the present invention, the rupture disk 20 includes a rupture disk valve body 21, a bursting disc 22 and a support ring 23. The outer wall of the rupture disk valve body 21 is sealed and connected to the inner wall of the cylinder 10. A guide cavity is provided in the rupture disk valve body 21 and passes through the axial direction of the cylinder 10. The bursting disc 22 is installed at one end of the rupture disk valve body 21 through the support ring 23 and closes the guide cavity. The bursting disc 22 can rupture under a specified pressure. With the above structure, only when the pressure of the annular fluid is greater than the rupture pressure of the bursting disc 22 and the bursting disc 22 is squeezed and ruptured, the guide cavity in the rupture disk valve body 21 is connected, and the annular fluid can flow from the first chamber 11 through the guide cavity to the second chamber 12 to push the slider 30 to slide, thereby opening the pressure relief outlet 14 and realizing automatic pressure relief of the annulus. Due to the presence of the rupture disk 20, the slider 30 will not be exposed to the harsh deep-water working environment too early, which provides a good protection for the slider 30 and prolongs the service life of the pressure relief device 100.

[0036] In the present invention, the rupture disk 20 is designed mainly for precise pressure control and protection of subsequent automatic pressure relief components (slider 30 and elastic member 40) from being exposed to harsh deep-water operating environments in advance, thereby preventing the pressure relief device 100 from failing and extending its service life.

[0037] In an optional example of this embodiment, the pressure relief threshold value (rupture threshold value) of the rupture disk 20 is changed by changing the thickness of the bursting disc 22, so that the pressure relief device 100 has better adaptability.

[0038] In an optional example of this embodiment, the rupture disc valve body 21 is threadedly connected to the inner wall of the cylinder 10. Specifically, the outer wall of the rupture disc valve body 21 is provided with an external thread, and the inner wall of the cylinder 10 is provided with an internal thread. The rupture disc valve body 21 and the cylinder 10 are threadedly matched to facilitate the installation and removal of the rupture disc 20.

[0039] In an optional example of this embodiment, a sealing ring 24 is further provided between the rupture disk valve body 21 and the cylinder 10 to achieve a sealing effect; this prevents the annular space closed pressure from flowing into the second chamber through the rupture disk 20 before the rupture threshold of the rupture disk 20 is reached, thereby ensuring the normal operation of the rupture disk 20.

[0040] In an optional example, the rupture disk valve body 21 is made of stainless steel 316 material and can operate in a high temperature environment of 450°C.

[0041] Furthermore, the rupture disk valve body 21 is designed with a hexagonal thread shape, which can be easily installed.

[0042] In an optional example, the bursting disc 22 can rupture at a specified pressure (rupture threshold), with a fast reaction speed, precise rupture, and a pressure control error within 5%.

[0043] In an alternative example, the outer diameter of the rupture disk 20 is 16 mm.

[0044] In an optional embodiment of the present invention, a one-way valve 50 is further provided between the rupture disk 20 and the slider 30 , and the one-way valve 50 only allows the fluid to flow from the rupture disk 20 toward the slider 30 .

[0045] In an optional example of this embodiment, the one-way valve 50 is a conical valve (such as Figure 4 As shown in the figure, its function is that when the pressure relief value is not reached, the conical valve can prevent the fluid in the first chamber 11 from flowing to the second chamber 12, and because it is a one-way valve, the fluid will only flow from the first chamber 11 to the second chamber 12 when the pressure value is reached, and there will be no reverse flow. The conical valve can also achieve the function of automatic pressure relief.

[0046] In an optional embodiment of the present invention, the pressure relief inlet 13 and the pressure relief outlet 14 are respectively opened on two opposite side walls of the cylinder 10 .

[0047] In an optional embodiment of the present invention, a plurality of pressure relief inlets 13 are provided on the cylinder 10 .

[0048] In an optional example of this embodiment, nine pressure relief inlets 13 are provided on the cylinder 10, and the inner diameter of each pressure relief inlet 13 is 5 mm, which can not only play a good circulation role, but also filter the annular space fluid to prevent debris from entering the pressure relief device 100 and making the pressure relief device 100 ineffective.

[0049] In the present invention, the annulus and the first chamber 11 are connected through the pressure relief inlet 13, and the annulus fluid flows into the first chamber 11 through the pressure relief inlet 13, so that when the trapped pressure in the annulus changes, the pressure relief device 100 can quickly sense the pressure change.

[0050] In an optional embodiment of the present invention, the elastic member 40 is a spring, and a spring base 60 is provided on the end wall of the cylinder 10 , and the spring is connected to the end wall through the spring base 60 .

[0051] In an optional embodiment of the present invention, a plurality of pressure relief devices 100 are disposed on the short section body 210 , and the plurality of pressure relief devices 100 are evenly distributed on the outer wall of the short section body 210 along the circumferential direction of the short section body 210 .

[0052] In an optional example of this embodiment, a layout design of six pressure relief devices 100 are used, which are arranged in a circular shape and evenly distributed on the short section body. Such a design can better sense the changes in the enclosed pressure in the annulus, thereby responding in time and better protecting the safety of the wellbore.

[0053] Please refer to Figures 1 to 6 Now, the specific use process of the pressure relief device 100 and the pressure relief nipple 200 for controlling the annular trap pressure proposed by the present invention is described in detail in conjunction with an embodiment:

[0054] 1. Install the pressure relief device 100 on the casing nipple and lower it into the casing;

[0055] 2. When the annular trap pressure rises to a set value (when the annular pressure is too high and threatens the safety of the wellbore), the bursting disc 22 of the rupture disk 20 ruptures and releases the annular pressure into the second chamber 12;

[0056] 3. The annular trap pressure acts on the elastic member 40 through the slider 30, causing the elastic member 40 to be compressed;

[0057] 4. After the slider 30 slides, the pressure relief outlet 14 is exposed, and the annular trap pressure is released through the pressure relief outlet 14;

[0058] 5. When the annular trap pressure does not reach the set value (when the annular pressure drops to a level that is not enough to cause damage to the wellbore), the compressed elastic member 40 rebounds and acts on the slider 30, and the slider 30 blocks the pressure relief outlet 14 again;

[0059] 6. When the annular trap pressure rises to the set value again, repeat steps 3, 4, and 5 to achieve automatic pressure relief.

[0060] The detailed explanation of the above-mentioned embodiments is only intended to explain the present invention so as to facilitate a better understanding of the present invention. However, these descriptions cannot be interpreted as limitations on the present invention for any reason. In particular, the various features described in different embodiments may also be arbitrarily combined with each other to form other embodiments. Unless there is a clear description to the contrary, these features should be understood to be applicable to any embodiment and are not limited to the described embodiments.

Claims

1. A pressure relief device for controlling annular trap pressure, characterized in that: The pressure relief device includes a cylinder, a rupture disk, a slider and an elastic member. The cylinder is hollow inside and forms a accommodating chamber closed at both ends. The rupture disk is arranged in the accommodating chamber. The periphery of the rupture disk is sealed and connected to the inner wall of the cylinder and divides the accommodating chamber into a first chamber and a second chamber. A pressure relief inlet connected to the first chamber is provided on the outer wall of the cylinder. The slider and the elastic member are located in the second chamber. The slider is slidably matched with the inner wall of the cylinder and can reciprocate along the axis of the cylinder. The two ends of the elastic member are respectively connected to the slider and the end wall of the cylinder. A pressure relief outlet is provided on the outer wall of the cylinder. When the elastic member is not compressed, the slider closes the pressure relief outlet. The pressure relief device releases the pressure in the annulus outside the cylinder to the annulus inside the cylinder according to the pressure.

2. The pressure relief device for controlling the annular closure pressure according to claim 1, characterized in that: The rupture disk includes a rupture disk valve body, a bursting disc and a support ring. The outer wall of the rupture disk valve body is sealed with the inner wall of the cylinder. A guide cavity is provided in the rupture disk valve body and passes through the cylinder along the axial direction. The bursting disc is installed at one end of the rupture disk valve body through the support ring and closes the guide cavity. The bursting disc can rupture under a specified pressure.

3. The pressure relief device for controlling the annular trap pressure according to claim 2, characterized in that: The rupture disk valve body is threadedly connected to the inner wall of the cylinder.

4. The pressure relief device for controlling the annular trap pressure according to claim 3, characterized in that: A sealing ring is also provided between the rupture disc valve body and the cylinder body.

5. The pressure relief device for controlling annular trap pressure according to claim 1, characterized in that: A one-way valve is further provided between the rupture disk and the slider, and the one-way valve only allows fluid to flow from the rupture disk toward the slider.

6. The pressure relief device for controlling annular trap pressure according to claim 1, characterized in that: The pressure relief inlet and the pressure relief outlet are respectively opened on two opposite side walls of the cylinder.

7. The pressure relief device for controlling annular trap pressure according to claim 1, characterized in that: The cylinder is provided with a plurality of pressure relief inlets.

8. The pressure relief device for controlling annular trap pressure according to claim 1, characterized in that: The elastic member is a spring, and a spring base is arranged on the end wall of the cylinder. The spring is connected to the end wall through the spring base.

9. A pressure relief nipple for controlling annular trap pressure, characterized in that: The pressure relief nipple comprises a nipple body and at least one pressure relief device for controlling the annular closure pressure as claimed in claim 1 installed on the nipple body, the nipple body having an axially through inner cavity, the cylinder being fixedly connected to the outer side wall of the nipple body, a through hole being provided on the side wall of the nipple body and cooperating with the pressure relief outlet, and the pressure relief inlet being provided on the side of the cylinder facing away from the nipple body.

10. The pressure relief nipple for controlling annular trap pressure according to claim 9, characterized in that: A plurality of the pressure relief devices are arranged on the short section body, and the plurality of the pressure relief devices are evenly distributed on the outer wall of the short section body along the circumferential direction of the short section body.

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