A high temperature and high pressure expansion joint sealing structure

Abstract

The present invention relates to the technical field of petroleum engineering, and provides a high-temperature and high-pressure expansion joint sealing structure, which is arranged between a central tube and an outer tube, wherein an annular accommodating groove is provided on the outer side surface of the central tube, a dynamic sealing mechanism is provided in the annular accommodating groove, and the dynamic sealing mechanism comprises two symmetrically arranged dynamic sealing components, wherein the dynamic sealing components comprise a pressure ring, a support ring and a V-shaped sealing ring, wherein the inner and outer sides of the pressure ring are in sliding contact with the central tube and the outer tube respectively, a V-shaped groove is provided on the inner side surface of the pressure ring, wherein the V-shaped groove is adapted to the V-shaped sealing ring, an annular frustum is fixedly installed on the inner side surface of the support ring, wherein the annular frustum is adapted to the V-shaped lip on the V-shaped sealing ring; and the V-shaped sealing ring is made of Aflas fluororubber material.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum engineering, and in particular to a high-temperature and high-pressure expansion joint sealing structure. Background Art

[0002] The high-temperature and high-pressure expansion joint is an expansion joint suitable for high-temperature and high-pressure wells in oil fields. It can greatly expand the range of ultra-deep well test application wells, provide a solid equipment foundation for ultra-deep well exploration and development, and provide strong technical support for the development of ultra-deep well petroleum engineering market.

[0003] The expansion joint includes a central tube and an outer tube. The central tube reciprocates in the outer tube, and a sealing structure is designed between the central tube and the outer tube. At present, the commonly used sealing form is O-ring sealing, which has the advantages of simple structure, low cost, simple installation and operation. It is often used in static sealing with pressure below 70MPa and temperature below 150℃. Combined with the structure and function of the expansion joint, the central tube and the outer tube are dynamically sealed. Simply using O-rings as sealing elements cannot guarantee the stability of its sealing performance, and is not suitable for the working environment of high temperature and high pressure wells in oil fields. Summary of the invention

[0004] In view of the defects in the prior art, the purpose of the present invention is to provide a high-temperature and high-pressure expansion joint sealing structure, which can stably achieve the sealing between the central tube and the outer tube and is suitable for the working environment of high-temperature and high-pressure wells in oil fields.

[0005] In order to achieve the above-mentioned object, the present invention is implemented by the following technical solutions: a high-temperature and high-pressure expansion joint sealing structure, which is arranged between a central tube and an outer tube, an annular receiving groove is provided on the outer side surface of the central tube, a dynamic sealing mechanism is provided in the annular receiving groove, and the dynamic sealing mechanism includes two symmetrically arranged dynamic sealing components, the dynamic sealing component includes a pressure ring, a support ring and a V-shaped sealing ring, the inner and outer sides of the pressure ring are in sliding contact with the central tube and the outer tube respectively, a V-shaped groove is provided on the inner side surface of the pressure ring, the V-shaped groove is adapted to the V-shaped sealing ring, an annular frustum is fixedly installed on the inner side surface of the support ring, and the annular frustum is adapted to the V-shaped lip on the V-shaped sealing ring;

[0006] The V-shaped sealing ring is made of Aflas fluororubber material.

[0007] Further, an annular sealing groove is formed on the outer side surface of the central tube, a static sealing assembly is arranged in the annular sealing groove, the static sealing assembly comprises an O-ring, support retaining rings are arranged on both sides of the O-ring, the inner side of the support retaining ring is in sliding contact with the bottom of the annular sealing groove, and the outer side of the support retaining ring is in sliding contact with the outer tube;

[0008] The O-type sealing ring is made of Aflas fluororubber material, and the supporting retaining ring is made of PEEK material.

[0009] Furthermore, the number of the dynamic sealing mechanisms is four groups, and the four groups of dynamic sealing mechanisms are arranged at intervals.

[0010] Furthermore, it also includes an annular pressure cap and an annular push plate, the inner end surface of the annular pressure cap is provided with an annular trapezoidal groove, the annular trapezoidal groove is adapted to the lower portion of the center tube, the outer end surface of the annular pressure cap is provided with a first annular guide surface extending inward and inclined downward, the annular push plate is arranged in the annular trapezoidal groove, and the annular push plate is provided with a second annular guide surface adapted to the first annular guide surface.

[0011] Furthermore, it also includes a sealing gasket, which is arranged between the annular push plates at the bottom of the central tube.

[0012] Furthermore, the number of the annular sealing grooves is two, and the two annular sealing grooves are arranged at intervals.

[0013] Beneficial effects of the present invention: The present invention provides a high-temperature and high-pressure expansion joint sealing structure. When the center tube is subjected to a load from the left side, the support ring of the dynamic seal assembly on the right side of the dynamic seal mechanism will move to the right, and the lip of the V-shaped seal ring will stretch in the radial direction; conversely, when the center tube is subjected to a load from the right side, the lip of the V-shaped seal ring of the dynamic seal assembly on the right side of the dynamic seal mechanism will stretch in the radial direction, thereby achieving a better seal between the center tube and the outer tube, and preventing liquid from leaking between the center tube and the outer tube. The dynamic seal mechanism has better sealing performance stability, and the Aflas fluororubber material is suitable for the working environment of high-temperature and high-pressure wells in oil fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of a partial cross-sectional structure of the present invention;

[0015] Figure 2 for Figure 1 Schematic diagram of the enlarged structure of part A in the middle.

[0016] Figure markings: 10-center tube, 11-annular receiving groove, 12-annular sealing groove, 20-outer tube, 30-dynamic sealing assembly, 31-pressure ring, 32-support ring, 33-V-shaped sealing ring, 34-V-shaped groove, 35-annular cone, 40-static sealing assembly, 41-O-ring, 42-support retaining ring, 50-annular pressure cap, 51-annular push plate, 52-first annular guide surface, 53-second annular guide surface, 54-sealing gasket. DETAILED DESCRIPTION

[0017] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0018] In this application, unless otherwise clearly specified and limited, the terms "connection" and "fixation" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0019] In the description of the present application, it should be understood that the terms "longitudinal", "lateral", "horizontal", "top", "bottom", "up", "down", "inside" and "outside" etc. indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0020] In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. In the description of the present invention, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0021] like Figure 1-2 As shown, the present invention provides a high-temperature and high-pressure expansion joint sealing structure, the expansion joint includes a central tube 10 and an outer tube 20. The structure is arranged between the central tube 10 and the outer tube 20. An annular receiving groove 11 extending inward is opened on the outer side surface of the central tube 10, and a dynamic sealing mechanism is arranged in the annular receiving groove 11. The dynamic sealing mechanism includes two symmetrically arranged dynamic sealing assemblies 30, which are named as the first dynamic sealing assembly 30 and the second dynamic sealing assembly 30 from left to right for the convenience of description.

[0022] The dynamic seal assembly 30 includes a pressure ring 31, a support ring 32 and a V-shaped sealing ring 33. The inner and outer sides of the pressure ring 31 are in sliding contact with the center tube 10 and the outer tube 20 respectively. A V-shaped groove 34 extending inward is provided on the inner side surface of the pressure ring 31, and the V-shaped groove 34 is adapted to the V-shaped sealing ring 33. An annular frustum 35 extending outward is fixedly mounted on the inner side surface of the support ring 32, and the annular frustum 35 is adapted to the V-shaped lip on the V-shaped sealing ring 33.

[0023] The V-shaped seal ring 33 is made of Aflas fluororubber material. Aflas fluororubber material has the following advantages: 1. Alkali and amine resistance. Due to its unique molecular structure, it has outstanding alkali and amine resistance. 2. Steam resistance. It has excellent durability against high temperature and high pressure steam. ( 200 series excluded). 3. Electrical insulation, volume resistivity is 10-16, which is an extremely excellent insulation. It also has excellent insulation for high voltage. 4. Heat resistance, continuous use temperature is 200°C, and for a short time, it also has excellent heat resistance for 250°C. 5. Acid resistance, it also has excellent acid resistance for strong acids such as sulfuric acid and hydrochloric acid. 6. Oil resistance, it has excellent oil resistance. In particular, it also has excellent durability for oils with anti-acidifying agents containing peramines. In addition, its durability for heavy oil is better than other rubbers.

[0024] When the center tube 10 is subjected to a load from the left side, the support ring 32 of the first dynamic seal assembly 30 will move to the right, and the lip of the V-shaped seal ring 33 will extend outward in the radial direction and be in close contact with the center tube 10 and the outer tube 20. Conversely, when the center tube 10 is subjected to a load from the right side, the pressure ring 31 of the second dynamic seal assembly 30 will move to the left, and the lip of the V-shaped seal ring 33 will extend outward in the radial direction and be in close contact with the center tube 10 and the outer tube 20. Therefore, regardless of whether the direction of the load is left or right, this structure can achieve a better seal between the center tube 10 and the outer tube 20, and prevent liquid from leaking between the center tube 10 and the outer tube 20. The dynamic seal mechanism has better stability in sealing performance, and the Aflas fluororubber material is suitable for the working environment of high-temperature and high-pressure wells in oil fields.

[0025] In one embodiment, an annular sealing groove 12 is formed on the outer side of the central tube 10, and a static sealing assembly 40 is disposed in the annular sealing groove 12. The static sealing assembly 40 includes an O-ring 41, and support retaining rings 42 are disposed on both sides of the O-ring 41, the inner side of the support retaining ring 42 is in sliding contact with the bottom of the annular sealing groove 12, and the outer side of the support retaining ring 42 is in sliding contact with the outer tube 20.

[0026] The O-type sealing ring 41 is made of Aflas fluororubber material, and the supporting retaining ring 42 is made of PEEK material.

[0027] PEEK material, whose Chinese name is polyetheretherketone, is a special plastic with a long-term use temperature of about 250 degrees. It has the characteristics of high temperature resistance, high wear resistance, high tensile strength, good flame retardancy, etc. PEEK material can be used to process PEEK parts of various specifications and can manufacture high-demand mechanical parts such as gears, bearings, valve seats, seals, pump wear rings, gaskets, etc.

[0028] The static seal adopts the above structure, and a support ring 42 made of PEEK material is added to the left and right of the O-ring 41. This structure can withstand high temperature and high pressure loads from both sides. When subjected to load, the O-ring 41 is squeezed and extends radially outward, making close contact with the central tube 10 and the outer tube 20, further improving the sealing performance, avoiding liquid leakage from between the central tube 10 and the outer tube 20, and further ensuring the reliability of the seal.

[0029] In one embodiment, the number of the dynamic sealing mechanisms is four, and the four groups of dynamic sealing mechanisms are arranged at intervals.

[0030] In one embodiment, an annular pressing cap 50 and an annular push plate 51 are further included. An annular trapezoidal groove is formed on the inner end surface of the annular pressing cap 50, and the annular trapezoidal groove is adapted to the lower part of the central tube 10. A first annular guide surface 52 extending inward and tilted downward is formed on the outer end surface of the annular pressing cap 50, and the annular push plate 51 is disposed in the annular trapezoidal groove, and a second annular guide surface 53 adapted to the first annular guide surface 52 is formed on the annular push plate 51.

[0031] When subjected to a load from the left side, the load will form a rightward thrust on the annular push plate 51. Under the action of the first annular guide surface 52 and the second annular guide surface 53, the annular pressure cap 50 will expand outward until it is in close contact with the outer tube 20. In this way, the load entering the annular receiving groove 11 will be reduced, further improving the sealing between the center tube 10 and the outer tube 20.

[0032] In one embodiment, a sealing gasket 54 is further included. The sealing gasket 54 is disposed between the bottom annular push plates 51 of the central pipe 10 .

[0033] When subjected to a load from the left side, the sealing gasket 54 can achieve sealing between the central tube 10 and the annular push plate 51, further preventing liquid from entering the annular receiving groove 11 from between the central tube 10 and the annular push plate 51, and further improving the sealing between the central tube 10 and the outer tube 20.

[0034] In one embodiment, there are two annular sealing grooves 12 , and the two annular sealing grooves 12 are arranged at intervals to ensure the reliability of the sealing.

[0035] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention.

[0036] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A high-temperature and high-pressure expansion joint sealing structure, arranged between the central tube and the outer tube, Features: An annular receiving groove is provided on the outer side surface of the central tube, a dynamic sealing mechanism is arranged in the annular receiving groove, the dynamic sealing mechanism includes two symmetrically arranged dynamic sealing components, the dynamic sealing components include a pressure ring, a support ring and a V-shaped sealing ring, the inner and outer sides of the pressure ring are in sliding contact with the central tube and the outer tube respectively, a V-shaped groove is provided on the inner side surface of the pressure ring, the V-shaped groove is adapted to the V-shaped sealing ring, an annular frustum is fixedly installed on the inner side surface of the support ring, the annular frustum is adapted to the V-shaped lip on the V-shaped sealing ring; It also includes an annular pressing cap and an annular push plate, wherein an annular trapezoidal groove is formed on the inner end surface of the annular pressing cap, and the annular trapezoidal groove is adapted to the lower part of the central tube, and a first annular guide surface extending inward and inclined downward is formed on the outer end surface of the annular pressing cap, and the annular push plate is arranged in the annular trapezoidal groove, and a second annular guide surface adapted to the first annular guide surface is formed on the annular push plate; when the annular push plate is subjected to a load, under the action of the first annular guide surface and the second annular guide surface, the annular pressing cap will expand outward until it is in close contact with the outer tube, so that the load entering the annular receiving groove is reduced, and the sealing performance is improved; It also includes a sealing gasket, which is arranged between the annular push plate at the bottom of the central tube; when the sealing gasket is subjected to a load, the sealing gasket can achieve sealing between the central tube and the annular push plate, prevent liquid from entering the annular receiving groove from between the central tube and the annular push plate, and improve the sealing between the central tube and the outer tube; The V-shaped sealing ring is made of Aflas fluororubber material.

2. A high temperature and high pressure expansion joint sealing structure according to claim 1, Features: An annular sealing groove is formed on the outer surface of the central tube, a static sealing assembly is arranged in the annular sealing groove, and the static sealing assembly includes an O-ring, and support retaining rings are arranged on both sides of the O-ring, the inner side of the support retaining ring is in sliding contact with the bottom of the annular sealing groove, and the outer side of the support retaining ring is in sliding contact with the outer tube; The O-type sealing ring is made of Aflas fluororubber material, and the supporting retaining ring is made of PEEK material.

3. A high temperature and high pressure expansion joint sealing structure according to claim 1, Features: The number of the dynamic sealing mechanisms is four, and the four groups of dynamic sealing mechanisms are arranged at intervals.

4. A high temperature and high pressure expansion joint sealing structure according to claim 2, Features: The number of the annular sealing grooves is two, and the two annular sealing grooves are arranged at intervals.

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