Reinforcing device of oil well casing

Abstract

The invention belongs to the technical field of oil exploitation, and discloses an oil well casing pipe strengthening device which comprises a strengthening liner pipe and an upper fixing assembly. A plurality of transverse annular grooves evenly distributed in the axis direction of the reinforced liner tube and a plurality of longitudinal grooves evenly distributed in the axis direction of the reinforced liner tube are formed in the peripheral face of the reinforced liner tube, and through holes are formed in the intersecting positions of the transverse annular grooves and the longitudinal grooves. The upper fixing assembly is fixedly connected with the reinforcing liner pipe, the reinforcing liner pipe and the upper fixing assembly can reinforce the casing pipe so as to prevent the casing pipe from deforming, and crude oil in an oil well flows out through the perforation, passes through the transverse annular groove and the longitudinal groove and then flows out through the through hole. The casing pipe can be strengthened through the strengthening liner pipe and the upper fixing assembly, the casing pipe can be effectively prevented from being damaged, the structure is simple, the construction technology is simple, convenient and rapid, and the cost is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of oil production, and in particular to a strengthening device for oil well casing. Background Art

[0002] At present, most cold-production heavy oil reservoirs have gone through the development stages of natural energy and water injection, and have problems such as low recovery rate and limited water injection development potential, and urgently need to change the development method. Thermal oil recovery technology based on steam injection is an effective enhanced oil recovery method with the advantage of high oil displacement efficiency. However, during the thermal recovery process, the working environment of the thermal injection wellbore is extremely complex, and problems such as casing thermal stress, sand production in the oil layer, and underground water storage can easily lead to casing damage. Therefore, when changing the thermal recovery development method, the wellbore needs to be strengthened to meet production.

[0003] In the prior art, gravel packing or high temperature resistant cement is often used for secondary completion, but the secondary completion is expensive and the process is complicated, wasting a lot of manpower and material resources. Summary of the invention

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

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] A strengthening device for oil well casing, wherein a casing is arranged in an oil well, and a perforation section on the casing is provided with spirally distributed perforations, and the strengthening device for oil well casing comprises:

[0007] A reinforced liner is arranged in the casing and located in the perforation section, and the outer circumferential surface of the reinforced liner is provided with a plurality of transverse annular grooves uniformly distributed along the axial direction of the reinforced liner and a plurality of longitudinal grooves uniformly distributed around the axial direction of the reinforced liner, and through holes are arranged at the mutually intersecting positions of the transverse annular grooves and the longitudinal grooves, so that the crude oil in the oil well can flow out through the perforations and then flow out through the transverse annular grooves and / or the longitudinal grooves through the through holes;

[0008] An upper fixing assembly is fixedly connected to the reinforced liner, and the upper fixing assembly can abut against the inner wall of the casing to fix the upper fixing assembly and the reinforced liner in the casing, and the reinforced liner and the upper fixing assembly can prevent the casing from deformation.

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

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

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

[0012] As an optional scheme, the upper fixed assembly includes an upper expansion casing, an expansion cone and an expansion starter, the upper expansion casing is fixedly connected to the upper end of the reinforced liner, and the outer wall of the upper expansion casing is provided with an upper metal seal, the expansion cone and the expansion starter are both arranged in the upper expansion casing, the expansion starter can drive the expansion cone to move along the axial direction of the casing to expand the upper expansion casing, and the expansion of the upper expansion casing can make the upper metal seal abut against the inner wall of the casing.

[0013] As an optional solution, the upper fixing assembly further includes a first inner tube, the first inner tube is connected to the expansion starter, and the working fluid can be transported into the expansion starter through the first inner tube to drive the expansion cone to move.

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

[0015] As an optional solution, the lower fixed assembly also includes a second inner tube, and the variable diameter expander is connected to the second inner tube. The second inner tube can drive the variable diameter expander to move along the axial direction of the casing and rotate around the axial direction of the casing, and at least two evenly distributed rollers are provided on the outer peripheral surface of the variable diameter expander. The working fluid can also be transported to the variable diameter expander through the second inner tube to make the roller move radially outward along the variable diameter expander.

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

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

[0018] Beneficial effects of the present invention:

[0019] The present invention provides a strengthening device for oil well casing, which includes a strengthening liner and an upper fixing assembly, wherein the strengthening liner is arranged in the casing and located in the perforation section of the casing, and the outer peripheral surface of the strengthening liner is provided with a plurality of transverse annular grooves uniformly distributed along the axial direction of the strengthening liner and a plurality of longitudinal grooves uniformly distributed around the axial direction of the strengthening liner, and a through hole is provided at the mutually intersecting position of the transverse annular grooves and the longitudinal grooves; the upper fixing assembly is fixedly connected with the strengthening liner, and the upper fixing assembly can abut against the inner wall of the casing so that the upper fixing assembly and the strengthening liner are fixed in the casing, the strengthening liner and the upper fixing assembly can strengthen the casing to prevent the casing from deformation, and the crude oil in the oil well flows out through the perforation and passes through the transverse reversing grooves and the longitudinal grooves and then flows out through the through hole. The strengthening device for oil well casing can strengthen the casing through the strengthening liner and the upper fixing assembly, can effectively prevent the casing from being damaged, has a simple structure, and a simple and quick construction process, which greatly reduces the cost. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0021] Figure 2 1 is a schematic diagram of the structure of the enhanced liner involved in the first embodiment of the present invention;

[0022] Figure 3 is an expanded view of a part of the perforation section of the casing in the example involved in the first embodiment of the present invention;

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

[0024] Figure 5 is a schematic structural diagram of a lower fixing assembly involved in Embodiment 1 of the present invention;

[0025] Figure 6 This is a schematic diagram of the structure of the oil well casing after the casing is strengthened by the strengthening device provided in the first embodiment of the present invention;

[0026] Figure 7 The structure of the strengthening device of the oil well casing provided by the second embodiment of the present invention is shown in FIG. Figure 1 ;

[0027] Figure 8 The structure of the strengthening device of the oil well casing provided by the second embodiment of the present invention is shown in FIG. Figure 2 .

[0028] In the figure:

[0029] 100, casing; 101, perforation;

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

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

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

[0033] 4. High temperature packer. DETAILED DESCRIPTION

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

[0035] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection or a detachable 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.

[0036] In the description of the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include the first feature being in direct contact with the second feature, or may include the first feature being in contact with the second feature through another feature between them instead of being in direct contact. Moreover, a first feature being "above", "above" and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0037] Embodiment 1

[0038] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0039] like Figure 1-Figure 6As shown, an embodiment of the present invention provides a strengthening device for oil well casing, wherein a casing 100 is arranged in the oil well, and a perforation section of the casing 100 is provided with spirally distributed perforations 101, and the distribution of the perforations 101 is prior art, and the perforations 101 can be arranged according to the actual needs of the oil well, and the arrangement of the perforations 101 is determined by the density and phase of the perforations 101. The strengthening device of the oil well casing comprises a strengthening liner 1 and an upper fixing assembly 2, wherein the strengthening liner 1 is arranged in the casing 100 and is located in the perforation section, the upper fixing assembly 2 is fixedly connected to the strengthening liner 1, and the upper fixing assembly 2 can abut against the inner wall of the casing 100 so that the upper fixing assembly 2 and the strengthening liner 1 are fixed in the casing 100, so as to enhance the strength of the casing 100 and effectively prevent the casing 100 from deformation; in order not to affect the crude oil production, the outer peripheral surface of the strengthening liner 1 is provided with a plurality of transverse annular grooves 11 and a plurality of longitudinal grooves 12, the plurality of transverse annular grooves 11 are evenly distributed along the axial direction of the strengthening liner 1, the plurality of longitudinal grooves 12 are evenly distributed around the circumference of the axis of the strengthening liner 1, and a through hole 13 is provided at the position where the transverse annular grooves 11 and the longitudinal grooves 12 intersect each other, and the crude oil in the oil well can flow out through the perforation 101 and pass through the transverse annular grooves 11 or the longitudinal grooves 12 and then flow out through the through hole 13 to carry out crude oil production. It should be noted that there is a certain gap between the reinforced liner 1 and the casing 100. The crude oil flows out through the perforations 101 and 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 is deformed, the inner wall of the casing 100 will partially abut the outer peripheral surface of the reinforced liner 1. The reinforced liner 1 serves as a supporting skeleton to prevent the casing 100 from being deformed, thereby preventing the casing 100 from further deformation and improving the strength of the casing 100.

[0040] The oil well casing reinforcement device can strengthen the casing 100 by strengthening the liner 1 and the upper fixing assembly 2, can effectively prevent the casing 100 from being damaged, has a simple structure, and a simple and fast construction process, which greatly reduces the cost.

[0041] It can be understood that when part of the inner wall of the casing 100 abuts against the outer peripheral surface of the enhanced liner 1, part of the transverse annular groove 11 or the longitudinal groove 12 will be blocked. Therefore, the distribution and number design of the transverse annular groove 11 and the longitudinal groove 12 play a vital role in the circulation efficiency of crude oil and the self-strength of the enhanced liner 1. Moreover, after the enhanced liner 1 is lowered into the casing 100 at a later stage, it cannot be guaranteed that the perforation section of the enhanced liner 1 and the casing 100 is perfectly matched. Preferably, the number of transverse annular grooves 11 a=kHθ / 360°, the number of longitudinal grooves 12 b=360° / θ, H is the length of the perforation section, k is the density of the perforation 101 (that is, the number of perforations 101 per unit length along the axial direction of the casing 100), and θ is the phase. For further explanation, for example, as Figure 3-4 As shown, Figure 3 is a planar development diagram of the perforation section of the casing 100 with a length of 1 m. Figure 3 It can be seen that k is 16. FIG. 4 is a cross-sectional view of the casing 100. There are two perforations 101 evenly distributed around the circumference on the cross-section, that is, the phase θ is 180°. Assuming that the length H of the perforation section is 10m, the number of transverse annular grooves 11 a=16*10*180° / 360°=80, and the number of longitudinal grooves 12 b=360° / 180°=2. The number of transverse annular grooves 11 and longitudinal grooves 12 is designed according to the density and phase of the perforations 101, so that the structural design is more scientific, and the crude oil circulation efficiency and the strength of the liner 1 itself can be guaranteed.

[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 as b=2 to ensure the circulation efficiency, and when the number of longitudinal grooves 12 is calculated to be greater than 6, it is designed as b=6 to ensure the self-strength of the reinforced liner 1.

[0043] Furthermore, the depth of the transverse annular groove 11 and the longitudinal groove 12 is not greater than 1 / 4 of the wall thickness of the reinforced liner 1 to ensure the strength of the reinforced 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 crude oil circulation efficiency.

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

[0046]

[0047] Specifically, continue to refer to Figure 1The upper fixed assembly 2 includes an upper expansion casing 21, an expansion cone 22 and an expansion starter 23. The upper expansion casing 21 is fixedly connected to the upper end of the enhanced liner 1. The upper expansion casing 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 enhanced liner 1. The outer walls of the tapered section and the small diameter section of the upper expansion casing 21 are both provided with an annular upper metal seal 211. The expansion cone 22 and the expansion starter 23 are provided on the upper expansion casing 21. Inside the casing 21, the expansion starter 23 can drive the expansion cone 22 to move upward after being started. When the expansion cone 22 moves upward, the conical section and the small diameter section of the upper expansion casing 21 are expanded, so that the upper metal seal 211 can be abutted and fixed with the inner wall of the casing 100, thereby achieving the upper expansion casing 21 and the reinforced liner 1 being fixed in the casing 100 at the same time. This structure applies the expansion tube technology, the inner diameter loss of the casing 100 is small, the construction process is simple, and the cost is greatly reduced.

[0048] Furthermore, the upper fixed component 2 also includes a first inner tube 24, which is connected to the expansion starter 23 and can extend out of the oil well. The 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, the expansion cone 22 is pushed upward, causing the conical section and the small diameter section of the upper expansion casing 21 to undergo plastic expansion deformation. When the upper expansion casing 21 expands, the metal seal is firmly abutted against the inner wall of the casing 100, and then the expansion cone 22 and the first inner tube 24 are pulled out, and the expansion starter 23 cannot be removed from the upper expansion casing 21, and a drill bit is required to drill through it to allow the crude oil to pass through.

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

[0050] Optionally, the upper expansion casing 21 and the lower expansion casing 31 may be connected to both ends of the reinforced liner 1 by threads.

[0051] In this embodiment, the structure of the lower expansion casing 31 is the same as the structural principle of the upper expansion casing 21, which will not be described again here.

[0052] The lower fixing assembly 3 also includes a second inner tube 33, and 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 casing 100 and rotate around the axial direction of the casing 100, and the outer peripheral surface of the variable diameter expander 32 is provided with at least two evenly distributed rollers 321, and the rollers 321 can move along the radial direction of the variable diameter expander 32. The working fluid can also be transported to the variable diameter expander 32 through the second inner tube 33 to make the rollers 321 move outward along the radial direction of the variable diameter expander 32. When in use, the variable diameter expander 32 can be first extended into the lower expansion casing 31 through the second inner tube 33, and then the working fluid is injected into the variable diameter expander 32 through the second inner tube 33 to make the rollers 321 expand outward, and then the second inner tube 33 is rotated and moved downward to realize the expansion of the lower expansion casing 31. After the expansion of the lower expansion casing 31 is completed, the variable diameter expander 32 and the second inner tube 33 are removed.

[0053] The present invention provides a reinforcement device for oil well casing, in which an upper expansion casing 21 and a lower expansion casing 31 are fixedly connected to a reinforcement liner 1 respectively, and a new layer of reinforcement pipe is inserted into the casing 100 by applying the expansion pipe technology, so that the strength of the casing 100 is fully guaranteed, and the inner diameter loss of the casing 100 is small. Compared with the cementing method of the prior art, it can effectively increase the flow area of ​​crude oil, facilitate later operations, and save costs.

[0054] Embodiment 2

[0055] The present embodiment provides a strengthening device for oil well casing, the structure of which is basically the same as that of the first embodiment. For the sake of convenience, only the differences are described. The differences are:

[0056] When the bottom of the perforation section is less than 100m from the bottom of the oil well, Figure 7 As shown, a high-temperature packer 4 can be provided at the lower end of the reinforced liner 1. The high-temperature packer 4 is set according to the setting principle. The high-temperature packer 4 is fixedly connected to the casing 100 and is located below the reinforced liner 1. The upper end of the reinforced liner 1 is still fixed by the upper fixing assembly 2. The upper fixing assembly 2, the reinforced liner 1 and the high-temperature packer 4 strengthen the casing 100.

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

[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 embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A strengthening device for oil well casing, wherein a casing (100) is arranged in the oil well, and a perforation section on the casing (100) is provided with spirally distributed perforations (101), characterized in that: The strengthening device of the oil well casing comprises: A reinforced liner (1) is arranged in the casing (100) and located in the perforation section, and the outer circumferential surface of the reinforced liner (1) is provided with a plurality of transverse annular grooves (11) uniformly distributed along the axial direction of the reinforced liner (1) and a plurality of longitudinal grooves (12) uniformly distributed around the axial direction of the reinforced liner (1), and a through hole (13) is provided at the mutually intersecting position of the transverse annular grooves (11) and the longitudinal grooves (12), so that crude oil in the oil well can flow out through the perforations (101) and then flow out through the through hole (13) after passing through the transverse annular grooves (11) and / or the longitudinal grooves (12); An upper fixing component (2) is fixedly connected to the reinforced liner (1), and the upper fixing component (2) can abut against the inner wall of the casing (100) so that the upper fixing component (2) and the reinforced liner (1) are fixed in the casing (100), and the reinforced liner (1) and the upper fixing component (2) can prevent the casing (100) from being deformed.

2. The oil well casing strengthening device according to claim 1, characterized in that: The number of the transverse annular grooves (11) a=kHθ / 360°, the number of the longitudinal grooves (12) b=360° / θ; H is the length of the perforation section, in units of m, k is the number of the perforations (101) per unit length, and θ is the phase.

3. The oil well casing strengthening device according to claim 2, characterized in that: The number of the longitudinal grooves (12) is 2≤b≤6.

4. The oil well casing strengthening device according to claim 1, characterized in that: The diameter of the through hole (13) is c=1.2d; d is the diameter of the perforation (101).

5. The oil well casing strengthening device according to claim 1, characterized in that: The upper fixed component (2) comprises an upper expansion casing (21), an expansion cone (22) and an expansion starter (23); the upper expansion casing (21) is fixedly connected to the upper end of the reinforced liner (1), and an upper metal seal (211) is arranged on the outer wall of the upper expansion casing (21); the expansion cone (22) and the expansion starter (23) are both arranged in the upper expansion casing (21); the expansion starter (23) can drive the expansion cone (22) to move along the axial direction of the casing (100) to expand the upper expansion casing (21); the expansion of the upper expansion casing (21) can make the upper metal seal (211) abut against the inner wall of the casing (100).

6. The oil well casing strengthening device according to claim 5, characterized in that: The upper fixing assembly (2) further comprises a first inner tube (24), the first inner tube (24) being connected to the expansion starter (23), and the working fluid can be transported into the expansion starter (23) through the first inner tube (24) to drive the expansion cone (22) to move.

7. The oil well casing strengthening device according to any one of claims 1 to 5, characterized in that: The invention also comprises a lower fixing assembly (3), wherein the lower fixing assembly (3) comprises a lower expansion casing (31) and a variable diameter expander (32), wherein the lower expansion casing (31) is fixedly connected to the lower end of the reinforced liner (1), and a lower metal seal (311) is provided on the outer wall of the lower expansion casing (31), and the variable diameter expander (32) can expand the lower expansion casing (31) so that the lower metal seal (311) abuts against the inner wall of the casing (100).

8. The oil well casing strengthening device according to claim 7, characterized in that: The lower fixing assembly (3) further comprises a second inner tube (33), the variable diameter expander (32) being connected to the second inner tube (33), the second inner tube (33) being capable of driving the variable diameter expander (32) to move along the axial direction of the casing (100) and to rotate around the axial direction of the casing (100), and at least two evenly distributed rollers (321) are provided on the outer peripheral surface of the variable diameter expander (32), and the working fluid can also be transported to the variable diameter expander (32) through the second inner tube (33) so that the roller (321) moves radially outwardly along the variable diameter expander (32).

9. The oil well casing strengthening device according to any one of claims 1 to 5, characterized in that: It also comprises a high temperature packer (4), wherein the high temperature packer (4) is fixedly arranged at the lower end of the reinforced liner (1).

10. The oil well casing strengthening device according to any one of claims 1 to 5, characterized in that: The lower end of the reinforced liner (1) extends to the bottom of the oil well.

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