A gas seal connection structure of a special coupling of a casing thread

Abstract

The application discloses a gas-tight connection structure of a special coupling of an oil casing thread, and relates to a gas conveying element, which comprises a gas conveying pipe and a movable thread pipe arranged on the gas conveying pipe; a connecting element, which comprises a fixed thread part arranged on the outer wall of the movable thread pipe, an inflation part arranged on the fixed thread part and a filling part; and a fixing element, which comprises a fixing pipe arranged between the fixed thread parts, an adjusting part, a sliding part and a limiting part arranged in the fixing pipe, and an opening part arranged on the limiting part. The gas-tight connection structure of the special coupling of the oil casing thread is characterized in that the movable thread pipe extrudes the limiting block to move backward, the limiting block is clamped into the thread of the movable thread pipe, the movable thread pipe is mutually restrained through the sliding ring, the limiting block moves backward, the isolation plate slides to make the expanded rubber particles enter the thread groove of the fixed thread pipe and expand to fill the thread groove of the fixed thread pipe, and the expansion of the expanded rubber particles improves the pressure in the thread groove of the fixed thread pipe, and the gas in the interior enters the air bag ring.

Description

Technical Field

[0001] This invention relates to the field of oil casing connection, and in particular to a gas-tight connection structure for a special thread of oil casing. Background Technology

[0002] In actual oilfield production, associated gas leaks caused by vibrations leading to displacement of the threaded connection between the casing and tubing, resulting in inadequate gas seals, pose a significant safety hazard. During deep and ultra-deep well oil and gas extraction, leaked flammable gases can diffuse and accumulate along the wellbore or in weaker areas of the geological strata if the seal is defective. These leaked gases may accumulate near the wellhead or erupt suddenly in geologically weak areas far from the well. If exposed to an open flame, they can easily ignite and even explode, leading to serious consequences. Even more challenging is the difficulty in accurately predicting the diffusion and accumulation locations of leaked gases within the geological strata, making the prevention and control of such safety hazards extremely difficult. Therefore, gas leaks caused by inadequate gas seals must be completely eliminated during oil extraction. Summary of the Invention

[0003] In view of the aforementioned problem of poor airtightness due to vibration displacement after installation of special threads on oil casing pipes, this application is made.

[0004] Therefore, the purpose of this invention is to provide an airtight connection structure for special threads in oil casing pipes, which aims to enhance the stability of the connection and improve the airtightness of the oil casing pipe threaded connection.

[0005] The above-mentioned technical problems are solved by the following technical solution: The present invention proposes a gas-tight connection structure for a special thread of an oil casing pipe, which includes two gas supply elements, wherein the gas supply element includes a gas supply pipe and a movable threaded pipe fixedly disposed on the gas supply pipe;

[0006] Two connecting elements, each connecting element including a fixed thread portion threaded to the outer wall of the moving threaded tube, an air-filling portion disposed on the lower wall of the fixed thread portion, and two filling portions disposed on the side wall of the fixed thread portion;

[0007] A fixing element, the fixing element comprising a fixing tube fixedly disposed between the fixed threaded portions, an adjusting portion disposed within the fixing tube, four sliding portions disposed within the fixing tube, four limiting portions disposed within the fixing tube, and an opening portion disposed on the limiting portions;

[0008] The moving threaded tube drives the limiting part to move, and the limiting part and the adjusting part cooperate to limit the moving threaded tube; the limiting part drives the two filling parts to open, limiting the moving threaded tube; the filling parts open to fill the inflation part.

[0009] In a preferred embodiment of the gas-tight connection structure of the special thread of the oil casing pipe described in this invention: the fixed thread part includes a fixed thread pipe with threads disposed on the outer wall of the moving thread pipe, and a connecting pipe fixedly disposed on the outer wall of the fixed thread pipe.

[0010] In a preferred embodiment of the gas-tight connection structure of the special thread of the oil casing pipe described in this invention: the inflation part includes a venting groove that passes through the lower wall of the fixed thread pipe, an air supply groove that is disposed inside the lower wall of the connecting pipe, and an airbag ring that is fixedly disposed on the side wall of the connecting pipe. A filter screen is disposed on the venting groove, and the venting groove is connected to the airbag ring through the air supply groove.

[0011] In a preferred embodiment of the gas-tight connection structure of the special thread of the oil sleeve pipe described in this invention: the filling part includes a filling groove disposed through both sides of the side wall of the fixed thread pipe, a storage groove disposed inside both sides of the side wall of the connecting pipe, and a connecting groove disposed inside both sides of the side wall of the connecting pipe. The storage groove is disposed above the connecting groove and is connected to the filling groove through the connecting groove. The two storage grooves respectively store expanded rubber particles and water.

[0012] In a preferred embodiment of the gas-tight connection structure of the special thread of the oil casing pipe described in this invention: the filling part further includes a sealing plate fixedly disposed below the storage groove and an isolation plate slidably disposed below the storage groove. The isolation plate and the sealing plate cooperate to isolate the storage groove and the communicating groove.

[0013] In a preferred embodiment of the gas-tight connection structure of the special thread of the oil casing pipe described in this invention: the adjusting part includes a fixed ring fixedly disposed inside the fixed pipe, two sliding rings slidably disposed inside the fixed pipe, the two sliding rings being disposed on both sides of the fixed ring, the two sliding rings being fixedly connected by a connecting rod, the connecting rod being disposed through the fixed ring and slidably connected to it.

[0014] In a preferred embodiment of the gas-tight connection structure of the special thread of the oil sleeve pipe described in this invention: the sliding part includes a sliding groove disposed on the side wall of the fixed pipe, a sliding block slidably disposed in the sliding groove, a connecting plate fixedly disposed on the side wall of the sliding block, a fixing plate fixedly disposed on the connecting plate, and sliding blocks disposed on both sides of the same sliding ring.

[0015] In a preferred embodiment of the gas-tight connection structure of the special thread of the oil casing pipe described in this invention: the limiting part includes a limiting block disposed in the fixed pipe, the fixed plates are all connected to the limiting block through telescopic sleeves, the fixed plates are all elastically connected to the limiting block through springs, and the side wall of the limiting block near the moving threaded pipe is inclined.

[0016] In a preferred embodiment of the gas-tight connection structure of the special thread of the oil sleeve pipe described in this invention: the opening part includes a vertical rod fixedly disposed at the telescopic end of the telescopic sleeve and an opening groove disposed on the side wall of the sliding groove.

[0017] In a preferred embodiment of the gas-tight connection structure of the special thread of the oil casing pipe described in this invention: the opening part further includes a sliding rod slidably disposed in the opening groove, one end of the sliding rod is connected to the vertical rod through a telescopic rod, the opening groove is connected to the storage groove, and the other end of the sliding rod is fixedly connected to the isolation plate.

[0018] The beneficial effects of this invention are as follows:

[0019] 1. After the two moving threaded tubes are connected to the fixed threaded tube, the front end of the moving threaded tube presses against the limiting block and moves it backward. The moving threaded tube continues to move forward. Due to the setting of the spring and the length of the connecting plate, the front ends of the two limiting blocks are respectively engaged in the threads of the moving threaded tube. Due to the setting of the sliding ring, when the moving threaded tube tends to move away from the fixed threaded tube, the two moving threaded tubes restrain each other through the setting of the two sliding rings, and restrict each other from moving away from the fixed threaded tube. Compared with the direct threaded connection of the traditional threaded thread, this device limits the movement of the moving threaded tube away from the fixed threaded tube, which enhances the stability of the connection.

[0020] 2. By moving backward through two limiting blocks, the isolation plate slides to connect the connecting groove and the storage groove. The expanding rubber particles and water source enter the thread groove of the fixed threaded pipe through the filling groove. The expanding rubber particles expand in the thread groove and fill the thread groove of the fixed threaded pipe. Compared with the direct threaded connection of the traditional threaded thread, this device makes the connection between the moving threaded pipe and the fixed threaded pipe more stable. The use of expanding rubber particles also improves the airtightness of the threaded connection.

[0021] 3. By using expanded rubber particles and a water source, the special oil pipes of the API standard already have sealing properties. The expansion of the expanded rubber particles increases the pressure in the thread groove of the fixed threaded pipe, and the gas inside enters the air bladder ring. Compared with the direct threaded connection of the traditional threaded thread, the expansion of the air bladder ring makes the sealing performance of the connection between the fixed threaded pipe and the tail of the moving threaded pipe higher. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Wherein:

[0023] Figure 1 A schematic diagram of the overall structure of a gas-tight connection structure for a special thread of an oil casing pipe is shown.

[0024] Figure 2 A schematic diagram showing the disassembled gas transmission element and connecting element of a special threaded oil casing pipe is shown;

[0025] Figure 3 A schematic diagram of the internal structure of a fixing element for a gas-tight connection structure with a special thread in an oil casing pipe is shown.

[0026] Figure 4 A first-view schematic diagram of the internal structure of a connecting element in a gas-tight connection structure with a special thread for an oil casing pipe is shown.

[0027] Figure 5 This is a second-view schematic diagram of the internal structure of a connecting element in a gas-tight connection structure with a special thread for an oil casing pipe.

[0028] Figure 6 This diagram shows a cross-sectional view of the internal structure of a connecting element in a gas-tight connection structure with a special thread for an oil casing pipe.

[0029] Figure 7 This illustrates a gas-tight connection structure for a special thread in an oil casing pipe. Figure 3 Enlarged schematic diagram of the structure at point A in the middle;

[0030] Figure 8 This illustrates a gas-tight connection structure for a special thread in an oil casing pipe. Figure 4 Enlarged schematic diagram of the structure at point B.

[0031] Legend: 1. Gas supply element; 11. Gas supply pipe; 12. Moving threaded pipe; 2. Connecting element; 21. Fixed threaded part; 211. Connecting pipe; 212. Fixed threaded pipe; 22. Inflating part; 221. Vent groove; 222. Gas supply groove; 223. Airbag ring; 23. Filling part; 231. Filling groove; 232. Connecting groove; 233. Storage groove; 234. Sealing plate; 235. Isolation plate; 3. Fixing element; 3 1. Fixed tube; 32. Adjusting part; 321. Fixed ring; 322. Connecting rod; 323. Sliding ring; 33. Sliding part; 331. Sliding groove; 332. Sliding block; 333. Connecting plate; 334. Fixed plate; 34. Limiting part; 341. Telescopic sleeve; 342. Spring; 343. Limiting block; 35. Opening part; 351. Vertical rod; 352. Telescopic rod; 353. Sliding rod; 354. Opening groove. Detailed Implementation

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0033] Reference Figures 1-8 This embodiment provides a gas-tight connection structure for a special threaded oil casing pipe, including two gas supply elements 1. Each gas supply element 1 includes a gas supply pipe 11 and a movable threaded pipe 12 fixedly disposed on the gas supply pipe 11. The gas supply pipe 11 and the movable threaded pipe 12 are connected.

[0034] Two gas supply elements 1 are respectively connected to two connecting elements 2. The connecting element 2 includes a fixed thread portion 21 with a thread on the outer wall of the moving threaded pipe 12. The fixed thread portion 21 includes a fixed threaded pipe 212 with a thread on the outer wall of the moving threaded pipe 12 and a connecting pipe 211 fixedly disposed on the outer wall of the fixed threaded pipe 212. The moving threaded pipe 12 and the fixed threaded pipe 212 are both trapezoidal threaded joints conforming to API standards. The two are sealed after being threaded together.

[0035] The lower wall of the fixed thread section 21 is provided with an inflation section 22. The inflation section 22 includes a venting groove 221 that passes through the lower wall of the fixed thread tube 212, an air supply groove 222 that is provided inside the lower wall of the connecting tube 211, and an airbag ring 223 that is fixedly provided on the side wall of the connecting tube 211. The venting groove 221 is connected to the airbag ring 223 through the air supply groove 222.

[0036] The side wall of the threaded portion 21 is provided with two filling portions 23, such as... Figure 4 , Figure 5 , Figure 6 and Figure 8The filling section 23 includes a filling groove 231 extending through both sides of the sidewall of the fixed threaded pipe 212, a storage groove 233 located inside both sides of the sidewall of the connecting pipe 211, and a connecting groove 232 located inside both sides of the sidewall of the connecting pipe 211. The storage groove 233 is located above the connecting groove 232 and is connected to the filling groove 231 through the connecting groove 232. The two storage grooves 233 respectively store expanded rubber particles and water. The expanded rubber particles are mainly based on natural or synthetic rubber, with the addition of water-absorbing resin, fillers, vulcanizing agents, accelerators, and other additives, and are made through a specific processing technology. These components work together to give the rubber particles both the elasticity and flexibility of rubber, as well as the special property of swelling when exposed to water. It should be noted that a filter screen is provided on the venting groove 221 to prevent the expanded rubber particles from falling into the venting groove 221.

[0037] The filling part 23 also includes a sealing plate 234 fixedly disposed below the storage groove 233 and an isolation plate 235 slidably disposed below the storage groove 233. The isolation plate 235 and the sealing plate 234 cooperate to isolate the storage groove 233 and the connecting groove 232. The sealing of the isolation plate 235 and the sealing plate 234 is achieved by rubber strips.

[0038] A fixing element 3 is fixedly disposed between the two connecting elements 2. The fixing element 3 includes a fixing tube 31 fixedly disposed between the fixed threaded portions 21, and an adjusting part 32 disposed inside the fixing tube 31. The adjusting part 32 includes a fixing ring 321 fixedly disposed inside the fixing tube 31, and two sliding rings 323 slidably disposed inside the fixing tube 31. The two sliding rings 323 are disposed on both sides of the fixing ring 321. The two sliding rings 323 are fixedly connected by a connecting rod 322. The connecting rod 322 passes through the fixing ring 321 and is slidably connected to it.

[0039] The fixed tube 31 is provided with four sliding parts 33. Each sliding part 33 includes a sliding groove 331 provided on the side wall of the fixed tube 31, a sliding block 332 slidably provided in the sliding groove 331, a connecting plate 333 fixedly provided on the side wall of the sliding block 332, a fixing plate 334 fixedly provided on the connecting plate 333, and sliding blocks 332 provided on both sides of the same sliding ring 323. The side wall of the limiting block 343 near the moving threaded tube 12 is inclined. The length of the sliding block 332 is set to ensure that when the inclined surface of one limiting block 343 is engaged with the thread on the moving threaded tube 12, the inclined surface of the other limiting block 343 can also be smoothly engaged with the thread on the moving threaded tube 12.

[0040] The fixed tube 31 is provided with four limiting parts 34. Each limiting part 34 includes a limiting block 343 disposed in the fixed tube 31. The fixed plate 334 is connected to the limiting block 343 through the telescopic sleeve 341. The fixed plate 334 is elastically connected to the limiting block 343 through the spring 342. When the elasticity of the spring 342 is sufficient, the isolation plate 235 can achieve a stable seal.

[0041] The limiting part 34 is provided with an opening part 35, which includes a vertical rod 351 fixedly disposed at the telescopic end of the telescopic sleeve 341; for example Figure 3 , Figure 6 and Figure 7 The opening slot 354 is provided on the side wall of the sliding groove 331; the opening part 35 also includes a sliding rod 353 slidably disposed in the opening slot 354. One end of the sliding rod 353 is connected to the vertical rod 351 through the telescopic rod 352. The opening slot 354 is connected to the storage slot 233. The other end of the sliding rod 353 is fixedly connected to the isolation plate 235 through the opening slot 354. The sliding rod 353 ensures the smooth movement of the sliding ring 323.

[0042] In one embodiment provided in this application, when two moving threaded tubes 12 are connected to a fixed threaded tube 212, the front end of the moving threaded tube 12 presses against the limiting block 343 and causes it to move backward. The moving threaded tube 12 continues to move forward. Due to the length of the spring 342 and the connecting plate 333, the front ends of the two limiting blocks 343 are respectively inserted into the threads of the moving threaded tube 12, thus limiting the moving threaded tube 12. Furthermore, due to the setting of the sliding ring 323, when the moving threaded tube 12 tends to move away from the fixed threaded tube 212, the two moving threaded tubes 12 restrain each other through the setting of the two sliding rings 323, thus limiting their movement away from the fixed threaded tube 212. This device limits the movement of the moving threaded tube 12 away from the fixed threaded tube 212, thereby enhancing the stability of the connection.

[0043] As the two limiting blocks 343 move backward, the isolation plate 235 slides, connecting the connecting groove 232 and the storage groove 233. This allows the expanding rubber particles in one storage groove 233 and the water source in the other storage groove 233 to enter the thread groove of the fixed threaded pipe 212 through the filling groove 231. The expanding rubber particles expand after contacting water in the thread groove of the threaded pipe 212 and the filling groove 231. The expanding rubber particles expand in the thread groove and fill the thread groove of the fixed threaded pipe 212. This device makes the connection between the moving threaded pipe 12 and the fixed threaded pipe 212 more stable, and the use of expanding rubber particles also improves the airtightness of the threaded connection.

[0044] It is worth noting that, due to the combination of the expanding rubber particles and the water source, the expanding rubber particles expand, and there is no need to fill the entire thread groove gap. They are only distributed in segments within the thread groove gap, which can further improve the sealing performance between the threads of the moving threaded pipe 12 and the fixed threaded pipe 212.

[0045] Because the special oil pipes of the API standard are already sealed, the expansion of the expanding rubber particles increases the pressure in the thread groove of the fixed threaded pipe 212. The gas inside enters the airbag ring 223 through the vent groove 221 and the gas delivery groove 222. The expansion of the airbag ring 223 makes the sealing at the connection between the fixed threaded pipe 212 and the tail of the moving threaded pipe 12 even better.

[0046] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A gas-tight connection structure for a special thread of an oil casing pipe, characterized in that: It includes two gas supply elements (1), each gas supply element (1) including a gas supply pipe (11) and a movable threaded pipe (12) fixedly disposed on the gas supply pipe (11). Two connecting elements (2), the connecting elements (2) include a fixed thread portion (21) threaded on the outer wall of the moving threaded tube (12), an air filling portion (22) disposed on the lower wall of the fixed thread portion (21), and two filling portions (23) disposed on the side wall of the fixed thread portion (21). The fixing element (3) includes a fixing tube (31) fixedly disposed between the fixed threaded portions (21), an adjusting portion (32) disposed in the fixing tube (31), four sliding portions (33) disposed in the fixing tube (31), four limiting portions (34) disposed in the fixing tube (31), and an opening portion (35) disposed on the limiting portion (34). The moving threaded tube (12) drives the limiting part (34) to move, and the limiting part (34) and the adjusting part (32) cooperate to limit the moving threaded tube (12); the limiting part (34) drives the two filling parts (23) to open, limiting the moving threaded tube (12); the filling parts (23) open to fill the air filling part (22). The fixed thread section (21) includes a fixed thread tube (212) with threads provided on the outer wall of the moving thread tube (12), and a connecting tube (211) fixedly provided on the outer wall of the fixed thread tube (212). The inflation part (22) includes a ventilation groove (221) that passes through the lower wall of the fixed threaded tube (212), an air delivery groove (222) that is disposed inside the lower wall of the connecting tube (211), and an airbag ring (223) that is fixedly disposed on the side wall of the connecting tube (211). The filling part (23) includes a filling groove (231) that passes through both sides of the side wall of the fixed threaded tube (212), a storage groove (233) that is disposed inside both sides of the side wall of the connecting tube (211), and a connecting groove (232) that is disposed inside both sides of the side wall of the connecting tube (211). The filling part (23) also includes a sealing plate (234) fixedly disposed below the storage groove (233) and an isolation plate (235) slidably disposed below the storage groove (233). The adjustment part (32) includes a fixed ring (321) fixedly disposed inside the fixed tube (31), and two sliding rings (323) slidably disposed inside the fixed tube (31). The two sliding rings (323) are disposed on both sides of the fixed ring (321), and the two sliding rings (323) are fixedly connected by a connecting rod (322). The sliding part (33) includes a sliding groove (331) disposed on the side wall of the fixed tube (31), a sliding block (332) slidably disposed in the sliding groove (331), a connecting plate (333) fixedly disposed on the side wall of the sliding block (332), a fixing plate (334) fixedly disposed on the connecting plate (333), and sliding blocks (332) disposed on both sides of the same sliding ring (323); The limiting part (34) includes a limiting block (343) disposed in the fixed tube (31). The fixed plates (334) are all connected to the limiting block (343) through telescopic sleeves (341). The fixed plates (334) are all elastically connected to the limiting block (343) through springs (342). The side wall of the limiting block (343) near the moving threaded tube (12) is inclined. The opening part (35) includes a vertical rod (351) fixedly installed at the telescopic end of the telescopic sleeve (341) and an opening groove (354) installed on the side wall of the sliding groove (331).

2. The gas-tight connection structure of the special thread of the oil casing pipe according to claim 1, characterized in that: A filter screen is provided on the ventilation groove (221), and the ventilation groove (221) is connected to the airbag ring (223) through the air delivery groove (222).

3. The gas-tight connection structure of the special thread of the oil casing pipe according to claim 2, characterized in that: The storage tank (233) is located above the connecting tank (232) and is connected to the filling tank (231) through the connecting tank (232). The two storage tanks (233) respectively contain expanded rubber particles and water.

4. The gas-tight connection structure of the special thread of the oil casing pipe according to claim 3, characterized in that: The isolation plate (235) and the sealing plate (234) cooperate to isolate the storage slot (233) and the connecting slot (232).

5. The gas-tight connection structure of the special thread of the oil casing pipe according to claim 4, characterized in that: The connecting rod (322) passes through the fixing ring (321) and is slidably connected to it.

6. The gas-tight connection structure of the special thread of the oil casing pipe according to claim 5, characterized in that: The opening part (35) further includes a sliding rod (353) slidably disposed in the opening groove (354). One end of the sliding rod (353) is connected to the vertical rod (351) through a telescopic rod (352). The opening groove (354) is connected to the storage groove (233). The other end of the sliding rod (353) is fixedly connected to the isolation plate (235).

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