Reinforcement device for oil well casing

Abstract

The application belongs to the technical field of oil exploitation, and discloses a reinforcing device for oil well casing, which comprises a reinforcing liner and an upper fixing assembly, the reinforcing liner is arranged in the casing and located at the perforated section of the casing, the outer circumferential surface of the reinforcing liner is provided with a plurality of transverse annular grooves which are uniformly distributed along the axial direction of the reinforcing liner and a plurality of longitudinal grooves which are uniformly distributed around the axial direction of the reinforcing liner, and a through hole is arranged at the intersecting position of the transverse annular grooves and the longitudinal grooves; the upper fixing assembly is fixedly connected with the reinforcing liner, and the reinforcing liner and the upper fixing assembly can reinforce the casing to prevent the casing from deforming, and the crude oil in the oil well flows out through the perforation, passes through the transverse annular grooves and the longitudinal grooves, and then flows out through the through hole. The reinforcing liner and the upper fixing assembly can reinforce the casing, which can effectively prevent the casing from being damaged, the structure is simple, the construction process is simple and fast, and the cost is greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of oil extraction technology, and in particular to a reinforcement device for oil well casing. Background Technology

[0002] Currently, most cold-developed heavy oil reservoirs have gone through natural energy and water injection development stages, resulting in problems such as low recovery rates and limited water injection development potential, necessitating a shift in development methods. Steam injection-based thermal oil recovery technology is an effective enhanced oil recovery method with high oil displacement efficiency. However, during thermal recovery, the wellbore operating environment is extremely complex, and issues such as casing thermal stress, reservoir sand production, and groundwater can easily lead to casing damage. Therefore, when switching to thermal recovery development methods, wellbore strengthening is necessary to meet production requirements.

[0003] In existing technologies, gravel backfilling or high-temperature resistant cement is often used for secondary well completion, but secondary well completion is expensive and the process is complex, wasting a lot of manpower and resources. Summary of the Invention

[0004] The purpose of this invention is to provide a strengthening device for oil well casing, which can strengthen the casing inside the oil well, and the construction process is simple and the cost is low.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A strengthening device for oil well casing, wherein a casing is installed inside the oil well, and the perforated section of the casing is provided with spirally distributed perforations, the strengthening device for the oil well casing includes:

[0007] A reinforced liner is installed inside the casing and located in the perforated section. The outer circumferential surface of the reinforced liner is provided with a plurality of transverse annular grooves evenly distributed along the axial direction of the reinforced liner and a plurality of longitudinal grooves evenly distributed around the axial direction of the reinforced liner. A through hole is provided at the intersection of the transverse annular grooves and the longitudinal grooves. Crude oil in the well can flow out through the perforation and then through the transverse annular grooves and / or the longitudinal grooves before flowing out through the through hole.

[0008] An upper fixing component is fixedly connected to the reinforcing liner, and the upper fixing component can abut against the inner wall of the sleeve to fix the upper fixing component and the reinforcing liner inside the sleeve. The reinforcing liner and the upper fixing component can prevent the sleeve from deforming.

[0009] As an alternative, the number of transverse annular grooves is a = kHθ / 360°, and the number of longitudinal grooves is b = 360° / θ; H is the length of the perforation segment in meters, k is the number of perforations per unit length, and θ is the phase.

[0010] As an alternative, the number of longitudinal grooves is 2 ≤ b ≤ 6.

[0011] As an alternative, the diameter of the through hole is c = 1.2d; where d is the diameter of the perforation hole.

[0012] As an optional embodiment, the upper fixing assembly includes an upper expansion sleeve, an expansion cone, and an expansion starter. The upper expansion sleeve is fixedly connected to the upper end of the reinforcing liner, and an upper metal seal is provided on the outer wall of the upper expansion sleeve. The expansion cone and the expansion starter are both disposed inside the upper expansion sleeve. The expansion starter can drive the expansion cone to move along the axial direction of the sleeve to expand the upper expansion sleeve. The expansion of the upper expansion sleeve can cause the upper metal seal to abut against the inner wall of the sleeve.

[0013] As an alternative, the upper fixing assembly further includes a first inner tube, which is connected to the expansion starter and allows working fluid to be delivered to the expansion starter to drive the expansion cone to move.

[0014] As an optional solution, a lower fixing assembly is also included, which includes a lower expansion sleeve and a variable diameter expander. The lower expansion sleeve is fixedly connected to the lower end of the reinforced liner, and a lower metal seal is provided on the outer wall of the lower expansion sleeve. The variable diameter expander can expand the lower expansion sleeve so that the lower metal seal abuts against the inner wall of the sleeve.

[0015] As an optional embodiment, the lower fixing assembly further includes a second inner tube, to which the variable diameter expander is connected. The second inner tube is capable of driving the variable diameter expander to move along the axial direction of the sleeve and rotate around the axial direction of the sleeve. The outer circumferential surface of the variable diameter expander is provided with at least two evenly distributed rollers. The working fluid can also be delivered to the variable diameter expander through the second inner tube so that the rollers move radially outward along the variable diameter expander.

[0016] As an optional solution, a high-temperature packer is also included, which is fixedly disposed at the lower end of the reinforced liner.

[0017] As an alternative, the lower end of the reinforced liner extends to the bottom of the oil well.

[0018] The beneficial effects of this invention are:

[0019] This invention provides a strengthening device for oil well casing, comprising a strengthening liner and an upper fixing assembly. The strengthening liner is disposed inside the casing and located in the perforated section of the casing. The outer circumferential surface of the strengthening liner has multiple transverse annular grooves evenly distributed along its axial direction and multiple longitudinal grooves evenly distributed around its axial direction. Through holes are provided at the intersections of the transverse annular grooves and longitudinal grooves. The upper fixing assembly is fixedly connected to the strengthening liner and abuts against the inner wall of the casing to fix the upper fixing assembly and the strengthening liner inside the casing. The strengthening liner and the upper fixing assembly strengthen the casing to prevent deformation. Crude oil in the well flows out through the perforation, passes through the transverse and longitudinal grooves, and then flows out through the through holes. This oil well casing strengthening device, through the strengthening liner and the upper fixing assembly, effectively prevents casing damage. It has a simple structure, is easy and quick to construct, and significantly reduces costs. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the oil well casing strengthening device provided in Embodiment 1 of the present invention;

[0021] Figure 2 This is a schematic diagram of the reinforced liner tube according to Embodiment 1 of the present invention;

[0022] Figure 3 This is an unfolded view of a portion of the perforated section of the casing in an example according to Embodiment 1 of the present invention;

[0023] Figure 4 This is a cross-sectional view of the sleeve in an example according to Embodiment 1 of the present invention;

[0024] Figure 5 This is a schematic diagram of the lower fixing component according to Embodiment 1 of the present invention;

[0025] Figure 6 This is a schematic diagram of the structure of the oil well casing after the strengthening device provided in Embodiment 1 of the present invention has completed the strengthening of the casing;

[0026] Figure 7 This is a schematic diagram of the structure of the oil well casing strengthening device provided in Embodiment 2 of the present invention. Figure 1 ;

[0027] Figure 8 This is a schematic diagram of the structure of the oil well casing strengthening device provided in Embodiment 2 of the present invention. Figure 2 .

[0028] In the picture:

[0029] 100. Casing; 101. Perforation;

[0030] 1. Reinforced liner; 11. Transverse annular groove; 12. Longitudinal groove; 13. Through hole;

[0031] 2. Upper fixing assembly; 21. Upper expansion sleeve; 211. Upper metal seal; 22. Expansion cone; 23. Expansion starter; 24. First inner tube;

[0032] 3. Lower fixing assembly; 31. Lower expansion sleeve; 311. Lower metal seal; 32. Variable diameter expander; 321. Roller; 33. Second inner tube;

[0033] 4. High-temperature packer. Detailed Implementation

[0034] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0035] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0036] In the description of this invention, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0037] Example 1

[0038] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0039] like Figures 1-6As shown, this embodiment of the invention provides a strengthening device for oil well casing. A casing 100 is installed inside the oil well, and the perforated section of the casing 100 is provided with spirally distributed perforations 101. The distribution of the perforations 101 is existing technology, and the perforations 101 can be arranged according to the actual needs of the oil well. The arrangement of the perforations 101 is determined by the density and phase of the perforations 101. The reinforcing device for the oil well casing includes a reinforcing liner 1 and an upper fixing component 2. The reinforcing liner 1 is installed inside the casing 100 and located in the perforated section. The upper fixing component 2 is fixedly connected to the reinforcing liner 1 and can abut against the inner wall of the casing 100 to fix the upper fixing component 2 and the reinforcing liner 1 inside the casing 100, thereby enhancing the strength of the casing 100 and effectively preventing deformation of the casing 100. In order not to affect crude oil extraction, the outer circumferential surface of the reinforcing liner 1 is provided with multiple transverse annular grooves 11 and multiple longitudinal grooves 12. The multiple transverse annular grooves 11 are evenly distributed along the axial direction of the reinforcing liner 1, and the multiple longitudinal grooves 12 are evenly distributed around the circumference of the axial direction of the reinforcing liner 1. Through holes 13 are provided at the intersection of the transverse annular grooves 11 and the longitudinal grooves 12. Crude oil in the oil well can flow out through the perforation 101 and then through the transverse annular grooves 11 or the longitudinal grooves 12 before flowing out through the through holes 13 for crude oil extraction. It should be noted that there is a certain gap between the reinforced liner 1 and the casing 100. After the crude oil flows out through the perforation 101, it enters the gap and then flows into the transverse annular groove 11 and the longitudinal groove 12 through the gap. The transverse annular groove 11 and the longitudinal groove 12 serve as channels for the flow of crude oil, and then flow out through the through hole 13. If the casing 100 deforms, part of the inner wall of the casing 100 will abut against the outer circumferential surface of the reinforced liner 1. The reinforced liner 1 serves as a supporting skeleton to prevent the casing 100 from deforming, thereby preventing further deformation of the casing 100 and improving the strength of the casing 100.

[0040] The strengthening device for the oil well casing can strengthen the casing 100 through the strengthening liner 1 and the upper fixing component 2, which can effectively prevent the casing 100 from being damaged. The structure is simple, the construction process is simple and quick, and the cost is greatly reduced.

[0041] It is understandable that when part of the inner wall of the casing 100 abuts against the outer circumferential surface of the reinforced liner 1, some of the transverse annular grooves 11 or longitudinal grooves 12 will be blocked. Therefore, the distribution and number design of the transverse annular grooves 11 and longitudinal grooves 12 play a crucial role in the efficiency of crude oil flow and the strength of the reinforced liner 1 itself. Moreover, after the reinforced liner 1 is later inserted into the casing 100, it cannot be guaranteed that the reinforced liner 1 and the perforation section of the casing 100 will perfectly match. Preferably, the number of transverse annular grooves 11 is a = kHθ / 360°, and the number of longitudinal grooves 12 is b = 360° / θ, where H is the length of the perforation section, k is the density of perforations 101 (i.e., the number of perforations 101 per unit length along the axial direction of the casing 100), and θ is the phase. For further illustration, exemplarily, such as Figure 3-4 As shown, Figure 3 This is a plan view of the perforated section of casing 100 with a length of 1m. Figure 3 As can be seen, k is 16. Figure 4 shows a cross-sectional view of the casing 100. Two perforations 101 are evenly distributed circumferentially on this cross-section, with a phase θ of 180°. Assuming the length H of the perforation section is 10m, the number of transverse annular grooves 11 is a = 16 * 10 * 180° / 360° = 80, and the number of longitudinal grooves 12 is b = 360° / 180° = 2. The number of transverse annular grooves 11 and longitudinal grooves 12 is designed based on the density and phase of the perforations 101 to make the structural design more scientific and to ensure crude oil flow efficiency and strengthen the liner 1 itself.

[0042] Optionally, the number of longitudinal grooves 12 is designed to be 2≤b≤6. That is, when the number of longitudinal grooves 12 is calculated to be 1, it is designed according to b=2 to ensure flow efficiency. When the number of longitudinal grooves 12 is calculated to be greater than 6, it is designed according to b=6 to ensure the strength of the reinforced liner 1.

[0043] Furthermore, the depth of the transverse annular groove 11 and the longitudinal groove 12 is no greater than 1 / 4 of the wall thickness of the reinforcing liner 1, so as to ensure the strength of the reinforcing liner.

[0044] Preferably, the diameter of the through hole 13 is c = 1.2d, where d is the diameter of the perforation 101. This structure can further ensure the efficiency of crude oil flow.

[0045] Referring to the table below, this table shows the number of transverse annular grooves 11 and longitudinal grooves 12 corresponding to different perforation densities k and different phases θ, as well as the diameter of the through hole 13 corresponding to different perforation diameters 101.

[0046]

[0047] Specifically, continue to refer to Figure 1The upper fixing assembly 2 includes an upper expansion sleeve 21, an expansion cone 22, and an expansion starter 23. The upper expansion sleeve 21 is fixedly connected to the upper end of the reinforcing liner 1. The upper expansion sleeve 21 includes a large-diameter section, a tapered section, and a small-diameter section. The tapered section is connected between the large-diameter section and the small-diameter section. The large-diameter section is fixedly connected to the reinforcing liner 1. The outer walls of the tapered section and the small-diameter section of the upper expansion sleeve 21 are provided with annular upper metal seals 211. The expansion cone 22 and the expansion starter 23 are disposed on the upper expansion sleeve 21. Inside the sleeve 21, after the expansion starter 23 is activated, it can drive the expansion cone 22 to move upward. When the expansion cone 22 moves upward, it expands the tapered section and the small diameter section of the upper expansion sleeve 21 so that the upper metal seal 211 can abut and fix with the inner wall of the sleeve 100. Thus, the upper expansion sleeve 21 and the reinforced liner 1 are simultaneously fixed inside the sleeve 100. This structure uses expansion tube technology, the inner diameter loss of the sleeve 100 is small, the construction process is simple, and the cost is greatly reduced.

[0048] Furthermore, the upper fixed assembly 2 also includes a first inner tube 24, which is connected to the expansion starter 23 and can extend outside the oil well. Working fluid can be injected into the expansion starter 23 through the first inner tube 24. The working fluid pressure of the expansion starter 23 gradually increases. When the working fluid pressure reaches a certain value, it pushes the expansion cone 22 upward, causing the conical section and small diameter section of the upper expansion casing 21 to undergo plastic expansion deformation. After the upper expansion casing 21 expands, the metal seal is firmly abutted against the inner wall of the casing 100. Then the expansion cone 22 and the first inner tube 24 are removed. However, the expansion starter 23 cannot be removed from the upper expansion casing 21 and needs to be drilled through with a drill bit to allow crude oil to pass through.

[0049] Optionally, refer to Figure 5 The reinforcing device for the well casing also includes a lower fixing assembly 3, which includes a lower expansion sleeve 31 and a variable diameter expander 32. The lower expansion sleeve 31 is fixedly connected to the lower end of the reinforcing liner 1. The outer wall of the lower expansion sleeve 31 is provided with a lower metal seal 311. The variable diameter expander 32 can expand the lower expansion sleeve 31 so that the lower metal seal 311 abuts against the inner wall of the casing 100, thereby fixing the lower expansion sleeve 31 to the casing 100. The upper expansion sleeve 21, the reinforcing liner 1, and the lower expansion sleeve 31 together reinforce the casing 100.

[0050] Optionally, the upper expansion sleeve 21 and the lower expansion sleeve 31 can be threaded to both ends of the reinforced liner 1.

[0051] In this embodiment, the structure of the lower expansion sleeve 31 is the same as that of the upper expansion sleeve 21, and will not be described again here.

[0052] The lower fixed assembly 3 also includes a second inner tube 33. The variable diameter expander 32 is connected to the second inner tube 33. The second inner tube 33 can drive the variable diameter expander 32 to move along the axial direction of the sleeve 100 and rotate around the axial direction of the sleeve 100. The outer circumferential surface of the variable diameter expander 32 is provided with at least two evenly distributed rollers 321. The rollers 321 can move radially along the variable diameter expander 32. The working fluid can also be delivered to the variable diameter expander 32 through the second inner tube 33 so that the rollers 321 move outward radially along the variable diameter expander 32. In use, the variable diameter expander 32 can be inserted into the lower expansion sleeve 31 through the second inner tube 33. Then, the working fluid is injected into the variable diameter expander 32 through the second inner tube 33 so that the rollers 321 expand outward. Then, the lower expansion sleeve 31 is expanded by rotating and moving downward through the second inner tube 33. After the lower expansion sleeve 31 is expanded, the variable diameter expander 32 and the second inner tube 33 are removed.

[0053] This invention provides a strengthening device for oil well casing, which fixes the upper expansion casing 21 and the lower expansion casing 31 to the strengthening liner 1 respectively. By applying expansion pipe technology, a new strengthening pipe is inserted into the casing 100, which fully ensures the strength of the casing 100 and minimizes the loss of the inner diameter of the casing 100. Compared with the existing cementing method, it can effectively increase the flow area of ​​crude oil, facilitate subsequent operations, and save costs.

[0054] Example 2

[0055] The oil well casing reinforcement device provided in this embodiment has a structure that is basically the same as that in Embodiment 1. For convenience, only the differences are described here. The differences are as follows:

[0056] When the bottom of the perforated section is less than 100m from the bottom of the well, such as Figure 7 As shown, a high-temperature packer 4 can be installed at the lower end of the reinforced liner 1. The high-temperature packer 4 sets the seal according to the setting principle. The high-temperature packer 4 is fixedly connected inside the sleeve 100 and located below the reinforced liner 1. The upper end of the reinforced liner 1 is still fixed by the upper fixing component 2. The upper fixing component 2, the reinforced liner 1, and the high-temperature packer 4 reinforce the sleeve 100.

[0057] Optionally, when the bottom of the perforated section is less than 100m from the bottom of the well, such as Figure 8 As shown, the lower end of the reinforced liner 1 can also be extended directly to the bottom of the oil well to further reduce costs.

[0058] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. Reinforcement device for oil well casing, in which a casing (100) is provided in the well, the perforated section of which is provided with a helical distribution of perforations (101), characterized in that, The oil well casing reinforcing device comprises: A reinforcing liner (1) is arranged in the casing (100) and located in the perforated section, and the outer circumferential surface of the reinforcing liner (1) is provided with a plurality of transverse annular grooves (11) uniformly distributed along the axial direction of the reinforcing liner (1) and a plurality of longitudinal grooves (12) uniformly distributed around the circumference of the axial direction of the reinforcing liner (1), and a through hole (13) is arranged at the intersection of the transverse annular groove (11) and the longitudinal groove (12), and the crude oil in the oil well can flow out through the perforation (101), pass through the transverse annular groove (11) and / or the longitudinal groove (12), and then flow out through the through hole (13); An upper fixing assembly (2) is fixedly connected with the reinforcing liner (1), and the upper fixing assembly (2) can abut against the inner wall of the casing (100) to fix the upper fixing assembly (2) and the reinforcing liner (1) in the casing (100), and the reinforcing liner (1) and the upper fixing assembly (2) can prevent the casing (100) from deforming; Further comprising a lower fixing assembly (3), the lower fixing assembly (3) comprises a lower expansion sleeve (31) and a variable-diameter expander (32), the lower expansion sleeve (31) is fixedly connected to the lower end of the reinforcing liner (1), and the outer wall of the lower expansion sleeve (31) is provided with a lower metal seal (311), and the variable-diameter expander (32) can expand the lower expansion sleeve (31) to make the lower metal seal (311) abut against the inner wall of the casing (100); The lower fixing assembly (3) further comprises a second inner tube (33), the variable-diameter expander (32) is connected with the second inner tube (33), the second inner tube (33) can drive the variable-diameter expander (32) to move along the axial direction of the casing (100) and rotate around the axial direction of the casing (100), and the outer circumferential surface of the variable-diameter expander (32) is provided with at least two uniformly distributed rollers (321), and working fluid can also be delivered into the variable-diameter expander (32) through the second inner tube (33) to make the rollers (321) move outwardly in the radial direction of the variable-diameter expander (32).

2. The oil well casing strengthening device of claim 1, wherein, The number a of the transverse annular grooves (11) is kHθ / 360°, and the number b of the longitudinal grooves (12) is 360° / θ; H is the length of the perforated section, unit m, k is the number of the perforations (101) per unit length, and θ is the phase.

3. The oil well casing strengthening device of claim 2, wherein, The number of the longitudinal grooves (12) is 2≤b≤6.

4. The oil well casing strengthening device of claim 1, wherein, The diameter c of the through hole (13) is 1.2d; d is the diameter of the perforation (101).

5. The oil well casing strengthening device of claim 1, wherein, The upper fixing assembly (2) comprises an upper expansion sleeve (21), an expansion cone (22) and an expansion starter (23), the upper expansion sleeve (21) is fixedly connected with the upper end of the reinforced liner (1), an outer wall of the upper expansion sleeve (21) is provided with an upper metal sealing element (211), the expansion cone (22) and the expansion starter (23) are both arranged in the upper expansion sleeve (21), the expansion starter (23) can drive the expansion cone (22) to move along the axial direction of the sleeve (100) to expand the upper expansion sleeve (21), the expansion of the upper expansion sleeve (21) can make the upper metal sealing element (211) abut against the inner wall of the sleeve (100).

6. The oil well casing strengthening device of claim 5, wherein, The upper fixing assembly (2) further comprises a first inner tube (24), the first inner tube (24) is connected with the expansion starter (23), and working fluid can be delivered into the expansion starter (23) through the first inner tube (24) to drive the expansion cone (22) to move.

7. The oil well casing reinforcement apparatus of any one of claims 1-5, wherein, Further comprising a high-temperature packer (4), the high-temperature packer (4) is fixedly arranged at the lower end of the reinforced liner (1).

8. The oil well casing reinforcement apparatus of any one of claims 1-5, wherein, The lower end of the reinforced liner (1) extends to the bottom of the oil well.

Images