Welding-free supporting disc and sand control screen pipe thereof

Abstract

The invention discloses a welding-free supporting disc and a sand control screen thereof, the supporting disc is sleeved and fixed on the outer circular surface of a base pipe (1), a sleeving hole of the supporting disc (2) is a taper hole (a), a conical gap (c) is formed between the taper hole (a) and the outer circular surface of the base pipe (1), and the conical gap (c) is a conical gap (c). A conical gap (c) is formed in the base pipe (1), a taper locking sleeve (3) consistent with the taper angle of the taper hole (a) is inserted into the conical gap (c), the supporting disc (2) is expanded on the base pipe (1) through the taper locking sleeve (3), the supporting disc is expanded on the base pipe with a sand control filter section through the taper locking sleeve structure, and the sand control screen pipe is formed. And the use reliability of the base tube is greatly improved.

Description

Technical Field

[0001] This invention belongs to the technical field of fixing and protecting sand control screens in oil well completion engineering. More specifically, it relates to a weld-free support plate and its sand control screen. Background Technology

[0002] Currently, China's offshore oil fields are gradually shifting from the continental shelf to deep-sea areas, resulting in increased well depth, more complex well conditions, and more severe formation conditions. This has led to the emergence of many high-temperature wells, high-pressure wells, and stronger acidity and alkalinity of formation fluids.

[0003] The existing method for fixing and protecting the filter unit, i.e., the sleeve, in sand control screen pipe-composite screen pipe is to install annular support discs at both ends of the sleeve, and the connection between the annular support discs and the sleeve is achieved by welding. This type of welded support disc is suitable for well conditions with good formation conditions, such as oil wells with low formation fluid pH, low formation pressure, and moderate temperature (not exceeding 200℃).

[0004] This method is not suitable for some high-temperature wells, high-pressure wells, and wells with high formation fluid pH. The main reasons are as follows: Firstly, impurities in the weld metal itself, such as carbon, sulfur, phosphorus, and oxides, become more active under high temperature and pressure, making them highly susceptible to chemical reactions with mineral ions in strongly acidic or alkaline liquid environments, thus causing (electro)chemical corrosion of the weld metal.

[0005] Secondly, welding is a complex metallurgical process. The support plate (usually made of stainless steel) and the base pipe (usually made of low alloy steel) connected to the weld metal will undergo local metallurgical phase transformation reactions. Due to the large rate of change and short cycle of the welding thermal cycle curve, the temperature rises rapidly (the highest temperature reaches 5000-8000K) and then cools rapidly. The grains cannot be sufficiently refined and reorganized, thus forming different metallographic structures in the heat-affected zone around the weld. The grain size in these zones is uneven and the mechanical properties are unstable, which can easily cause hot cracks under high temperature and high pressure.

[0006] Thirdly, under normal circumstances, post-weld heat treatment is necessary to obtain a uniform and refined microstructure in the weld and the heat-affected zone to improve the performance of the welded joint. However, given the specific processing and assembly process of composite screen pipes, it is impossible to perform heat treatment on the support plate after welding, so welding defects cannot be avoided. Summary of the Invention

[0007] To address the issue that the reliability of connecting the support plate to the base pipe using traditional welding processes in harsh well conditions is insufficient, which poses a safety hazard to downhole sand control operations, this invention provides a weld-free support plate and its sand control screen. By making the mounting hole of the support plate into a conical hole structure, and using a tapered locking sleeve inserted into the conical hole to lock the support plate to the base pipe, no welding is required, thus avoiding the impact of welding defects and other issues. It can well adapt to high-temperature wells, high-pressure wells, and conditions with high acidity or alkalinity of formation fluids.

[0008] The present invention adopts the following technical solution: On one hand, the present invention provides a weldless support plate, which is fitted and fixed on the outer circular surface of the base tube. The fitting hole of the support plate is a conical hole, and a conical gap is formed between the conical hole and the outer circular surface of the base tube. A tapered locking sleeve with the same cone angle as the conical hole is inserted into the conical gap, and the tapered locking sleeve tightens the support plate on the base tube.

[0009] Furthermore, a radial pin hole I is provided near the large end of the tapered locking sleeve, and a radial pin hole II is provided on the support plate. When the tapered locking sleeve is inserted into the conical gap, the radial pin hole I is located on the outside of the support plate. The tapered locking sleeve is locked to the base tube by a cylindrical pin I inserted into the radial pin hole I, and the support plate is locked to the tapered locking sleeve by a cylindrical pin II inserted into the radial pin hole II.

[0010] Preferably, the mounting holes of the support plate include a conical hole and a cylindrical hole, the cylindrical hole being located at the small end of the conical hole, and the cylindrical hole being in contact with the outer circular surface of the base tube.

[0011] Furthermore, a corrugated conical surface with elastic tension is formed near the small end surface of the tapered locking sleeve.

[0012] Preferably, the outer diameter of the large end of the tapered locking sleeve is larger than the inner diameter of the large end of the tapered hole of the support plate.

[0013] On the other hand, the present invention also provides a sand-proof screen pipe, which includes a base pipe and a sand-proof screen section located on the base pipe, wherein the aforementioned weldless support plate is installed at both ends of the sand-proof screen section.

[0014] The technical solution of this invention has the following advantages: A. This invention replaces the welding process with an insertion wedge-type locking seal. After the tapered locking sleeve is wedged into the tapered hole of the support plate, the tension (restoring force) generated by its spring-like structure can firmly fix the support plate to the base tube. The structure is simple, does not require welding, and greatly improves the reliability of the base tube.

[0015] B. The present invention provides a corrugated conical hole in the small diameter section of the tapered locking sleeve, so that the small diameter end face of the tapered locking sleeve is tightly fitted with the inner surface of the conical hole of the support plate and the outer surface of the base pipe under the action of mechanical force. Under the pressure differential of oil well operation, the corrugated shape will be further squeezed and unstable, and undergo a large bending deformation along the axial direction, thereby squeezing the inner and outer mating surfaces more tightly and achieving a seal between the metal surfaces. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the tapered locking sleeve structure provided by the present invention; Figure 2 This is a schematic diagram of the support disk structure provided by the present invention; Figure 3 This invention provides a schematic diagram before assembly. Figure 4 This is a schematic diagram of the assembled version of the present invention; Figure 5 This invention provides the application of a weld-free support plate on a sand-proof screen pipe.

[0018] The symbols in the diagram represent the following: 1-Base pipe, 11-Sand control filter section; 2-Support plate, 21-Radial pin hole II; 3-Tapered locking sleeve, 31-Corrugated conical surface, 32-Radial pin hole I; 4-Cylindrical pin I; 5-Cylindrical pin II.

[0019] a - conical hole, b - cylindrical hole, c - conical clearance. Detailed Implementation

[0020] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0023] like Figure 1-4 As shown, this invention provides a weldless support plate, which is fitted and fixed to the outer circumference of a base tube 1. The fitting hole of the support plate 2 is preferably a conical hole a, forming a conical gap c between the conical hole a and the outer circumference of the base tube 1. A tapered locking sleeve 3, with the same cone angle as the conical hole a, is inserted into the conical gap c. The tapered locking sleeve 3 tightens the support plate 2 onto the base tube 1. It can be seen that this invention eliminates the need to weld the support plate to the base tube (or sleeve). The tapered locking sleeve 3 quickly achieves the compression fixation between the support plate and the base tube, thus avoiding technical problems such as weld cracking and oxidation corrosion at the weld joint.

[0024] At the same time, such as Figure 1 As shown, the present invention also provides a radial pin hole I32 near the large end of the tapered locking sleeve 3, such as... Figure 2 As shown, a radial pin hole II21 is provided on the support plate 2, as... Figure 4As described above, when the tapered locking sleeve 3 is inserted into the conical gap c, the radial pin hole I32 is located on the outside of the support plate 2. The tapered locking sleeve 3 is locked to the base tube 1 by the cylindrical pin I4 inserted into the radial pin hole I32, and the support plate 2 is locked to the tapered locking sleeve 3 by the cylindrical pin II5 inserted into the radial pin hole II21. This achieves a fixed connection between the support plate 2, the tapered locking sleeve 3, and the base tube 1. The fitting hole of the support plate 2 includes two parts, namely a conical hole a and a cylindrical hole b. The cylindrical hole b is located at the small end of the conical hole a, that is, an equal-diameter extension of the conical hole a. The cylindrical hole b fits against the outer circular surface of the base tube 1. More preferably, the outer diameter of the large end of the tapered locking sleeve 3 is larger than the inner diameter of the large end of the conical hole of the support plate 2, which makes it easier to achieve centering and locking during installation. In addition, the present invention also forms a corrugated conical surface 31 with elastic tension on the surface near the small end of the tapered locking sleeve 3.

[0025] In this invention, the inner hole of the tapered locking sleeve 3 matches the outer circle of the base tube 1. The outer circle of the tapered locking sleeve 3 is an outer conical cylindrical surface. The inner hole of the support plate 2 that fits onto the base tube 1 is divided into two sections: one section is a cylindrical hole b that matches the outer circle of the base tube 1, and the other section is a conical hole a that matches the outer conical cylindrical surface on the tapered locking sleeve 3. The outer conical cylindrical surface on the tapered locking sleeve 3 is inserted into the conical hole a of the support plate 2. Radial pin holes II and I are respectively provided on the support plate 2 and the tapered locking sleeve 3, and cylindrical pins II and I are respectively inserted into them. The tapered locking sleeve 3 and the base tube 1 are locked together by the cylindrical pin I, and the support plate and the tapered locking sleeve 3 are locked together by the cylindrical pin II. The outer ends of the two radial pin holes and the two cylindrical pins are welded and then polished.

[0026] This invention replaces the welding process with an insertion wedge-type locking seal. On the one hand, after the tapered locking sleeve 3 is wedged into the tapered hole a of the support plate 2, the tension (restoring force) generated by its spring-like structure can firmly fix the support plate 2 to the base pipe 1. On the other hand, the small-diameter end face of the corrugated conical surface 31 of the tapered locking sleeve 3 is tightly fitted together with the inner surface of the tapered hole a of the support plate 2 and the outer surface of the base pipe 1 under the action of mechanical force. Under the pressure differential of the oil well operation, the corrugated conical surface 31 will be further squeezed and unstable, and undergo a large bending deformation along the axial direction, thereby squeezing the inner and outer mating surfaces more tightly, thus achieving a seal between the metal surfaces.

[0027] like Figure 5 The sand-control screen pipe structure shown in this invention has the support plate 2 disclosed in this invention installed on both ends of the sand-control filter section 11 of the base pipe 1. The support plate is fixed to both ends of the sand-control filter section on the base pipe by the specific fastening structure set by this invention. No welding is required, the structure is simple, and there are no defects caused by welding. The sand-carrying fluid of the formation enters the base pipe 1 after being filtered by the sand-control filter section 11, and the filtered sand-free fluid is output from the base pipe 1.

[0028] Any aspects not described in this invention are applicable to existing technologies.

[0029] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A weld-free support plate, which is fitted and fixed to the outer circumferential surface of the base tube (1), characterized in that, The mounting hole of the support plate (2) is a conical hole (a), and a conical gap (c) is formed between the conical hole (a) and the outer circular surface of the base tube (1). A tapered locking sleeve (3) with the same cone angle as the conical hole (a) is inserted into the conical gap (c). The tapered locking sleeve (3) tightens the support plate (2) onto the base tube (1).

2. The weldless support plate according to claim 1, characterized in that, A radial pin hole I (32) is provided near the large end of the tapered locking sleeve (3), and a radial pin hole II (21) is provided on the support plate (2). When the tapered locking sleeve (3) is inserted into the conical gap (c), the radial pin hole I (32) is located on the outside of the support plate (2). The tapered locking sleeve (3) is locked to the base tube (1) by a cylindrical pin I (4) inserted into the radial pin hole I (32), and the support plate (2) is locked to the tapered locking sleeve (3) by a cylindrical pin II (5) inserted into the radial pin hole II (21).

3. The weldless support plate according to claim 2, characterized in that, The mounting holes of the support plate (2) include a conical hole (a) and a cylindrical hole (b). The cylindrical hole (b) is located at the small end of the conical hole (a) and is in contact with the outer circular surface of the base tube (1).

4. The weldless support plate according to any one of claims 1-3, characterized in that, A corrugated conical surface (31) with elastic tension is formed at the small end surface near the tapered locking sleeve (3).

5. The weldless support plate according to claim 4, characterized in that, The outer diameter of the large end of the tapered locking sleeve (3) is larger than the inner diameter of the large end of the tapered hole of the support plate (2).

6. A sand-control screen pipe, comprising a base pipe (1) and a sand-control screen section (11) located on the base pipe (1), characterized in that, At both ends of the sand screen section (11), a weldless support plate (2) as described in any one of claims 1-5 is installed.

Images