Casing pipe capable of reducing thermal stress

Abstract

The utility model discloses a casing pipe capable of reducing thermal stress, relates to the relevant field of casing pipes, and aims to solve the problems that in the prior art, when the casing pipe enters a thermal production well, a shear pin between an inner casing pipe and an outer casing pipe is possibly sheared off in advance due to unknown underground conditions, and the inner casing pipe and the outer casing pipe can move relatively under the condition that the inner casing pipe and the outer casing pipe are not heated. The problems that the position of a compensation interval is used in advance, compensation cannot be carried out or compensation is insufficient after heating, a casing pipe continues to expand and deform under the thermal action, and a cement sheath in a well is damaged are solved. According to the outer sleeve, a first inner arc-shaped ring groove is formed in the lower end of the inner surface of a first sleeve body, and an inner arc-shaped limiting ring groove is formed in the inner surface of the first inner arc-shaped ring groove; a first outer arc-shaped ring groove is formed in the upper end of the outer surface of the second sleeve body, the first outer arc-shaped ring groove corresponds to the first inner arc-shaped ring groove in position, and the first outer arc-shaped ring groove and the first inner arc-shaped ring groove are the same in height.

Description

Technical Field

[0001] The utility model relates to the relevant field of sleeves, in particular to a sleeve capable of reducing thermal stress. Background Art

[0002] Thermal recovery is a method of production that can effectively utilize oil and gas resources. Thermal recovery is the main means of heavy oil well development at present. It can effectively increase the temperature of the oil layer, reduce the viscosity of the heavy oil, and make the heavy oil easy to flow, thereby producing the heavy oil, forming a technical framework represented by steam injection, steam drive, hot water drive, oil layer fire, electromagnetic heating and other technologies.

[0003] During the mining process, the temperature in the well will gradually increase. Affected by factors such as high temperature, high pressure and corrosion, the casing of thermal recovery wells will often suffer from wear, cracks, corrosion, etc., which will affect the stability of the well wall. The casing will expand and deform under the action of heat, causing the wellhead to rise and destroy the cement ring in the well. In severe cases, it may even cause the oil well to be scrapped.

[0004] However, when the casing enters the thermal recovery well, the shear nails between the inner and outer casings may be cut off in advance due to unclear downhole conditions. The inner and outer casings can move relative to each other without being heated, and the compensation interval position is used in advance. After heating, compensation may not be possible or insufficient, causing the casing to continue to expand and deform under the action of heat, thereby damaging the cement ring in the well. Utility Model Content

[0005] The utility model aims to provide a casing capable of reducing thermal stress, so as to solve the problem proposed in the above-mentioned background technology that when the casing enters a thermal recovery well, the shear nails between the inner and outer casings may be cut off in advance due to the unknown downhole conditions, the inner and outer casings may move relative to each other without being heated, the compensation interval position is used in advance, and compensation may not be performed or compensation is insufficient after heating, so that the casing will continue to expand and deform under the action of heat, thereby damaging the cement ring in the well.

[0006] To achieve the above object, the utility model provides the following technical solutions: a sleeve capable of reducing thermal stress, comprising an outer sleeve and an inner sleeve, the outer sleeve comprising a first sleeve body, the inner sleeve comprising a second sleeve body; the outer sleeve comprising a first inner arc-shaped annular groove at the lower end of the inner surface of the first sleeve body, the inner surface of the first inner arc-shaped annular groove comprising an inner arc-shaped limiting annular groove;

[0007] A first outer arcuate annular groove is formed at the upper end of the outer surface of the second sleeve body, the first outer arcuate annular groove corresponds to the first inner arcuate annular groove in position, and the first outer arcuate annular groove has the same height as the first inner arcuate annular groove;

[0008] A limiting spring piece is arranged outside the second sleeve tube body in the space between the first outer arc-shaped annular groove and the first inner arc-shaped annular groove, the other end of the limiting spring piece extends into the inner arc-shaped limiting annular groove, and an elastic block is arranged between the limiting spring piece and the second sleeve tube body;

[0009] The space between the first outer arc-shaped annular groove and the first inner arc-shaped annular groove is filled with a hot melt component.

[0010] Preferably, a lower extension tube body is provided at the lower end of the first sleeve tube body, and a plurality of first limiting protrusion bars are provided in a circular array inside the lower extension tube body, and a limiting sliding groove is formed between two adjacent first limiting protrusion bars.

[0011] Preferably, an outer pressure ring is provided at the lower end of the outer part of the second sleeve body, and a plurality of second limiting protrusions are provided in a circular array along the upper end of the outer pressure ring on the outer part of the second sleeve body, and the second limiting protrusions correspond to the positions of the limiting sliding grooves.

[0012] Preferably, a second inner arc-shaped annular groove is formed on the inner surface of the first sleeve body along the lower end of the first inner arc-shaped annular groove, and a second outer arc-shaped annular groove is formed on the outer surface of the second sleeve body along the lower end of the first outer arc-shaped annular groove, and the second inner arc-shaped annular groove and the second outer arc-shaped annular groove are arranged opposite to each other.

[0013] Preferably, a plurality of shear pins are fixed in the space between the second inner arc-shaped annular groove and the second outer arc-shaped annular groove, and two ends of the shear pins are respectively connected to the first sleeve body and the second sleeve body.

[0014] Preferably, an upper joint is provided at the upper end of the outer sleeve, and the upper joint includes an outer connecting tube body and an inner connecting tube body, the outer connecting tube body is located at the upper end of the inner connecting tube body, the inner connecting tube body is located at the upper end inside the first sleeve tube body, and a compensation area is formed inside the first sleeve tube body along the second sleeve tube body and the inner connecting tube body.

[0015] Preferably, an upper head is provided at the upper end of the upper joint, and the upper head includes an arc-shaped head body and an embedded tube, the arc-shaped head body is located at the upper end of the embedded tube, and the embedded tube is located at the upper end inside the external connecting tube body.

[0016] Compared with the prior art, the beneficial effects of the utility model are:

[0017] In the utility model, the outer sleeve is connected to the inner sleeve so that one end of the limiting spring piece is stuck in the inner arc-shaped limiting ring groove. At this time, the elastic blocks in the first inner arc-shaped ring groove and the first outer arc-shaped ring groove are in an elastically stretched state, and then the space is sealed by the hot melt. The hot melt is in a solid state before reaching the melting point temperature, and is stuck between the first inner arc-shaped ring groove and the first outer arc-shaped ring groove, so that the outer sleeve and the inner sleeve will not be staggered due to going down the well, thereby avoiding the shear pins from being cut off in advance. The setting of the limiting spring piece and the elastic block further provides downhole protection and avoids the breakage of the hot melt. The double structure ensures the safety of the shear pins going down the well, solves the problem that the shear pins between the inner and outer sleeves may be cut off in advance due to the unknown downhole conditions when the casing enters the thermal recovery well, the inner and outer sleeves can move relative to each other without being heated, the compensation interval position is used in advance, and compensation may not be performed or compensation is insufficient after being heated, so that the casing will continue to expand and deform under the action of heat, destroying the cement ring in the well. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the overall structure of a sleeve capable of reducing thermal stress according to the utility model;

[0019] Figure 2 This is a front view of a sleeve capable of reducing thermal stress according to the utility model;

[0020] Figure 3 This is a structural cross-sectional view of a sleeve capable of reducing thermal stress according to the utility model;

[0021] Figure 4 This is an enlarged view of the structure at point A of a sleeve capable of reducing thermal stress in the utility model;

[0022] Figure 5 This is a schematic structural diagram of an outer sleeve of a sleeve capable of reducing thermal stress according to the utility model;

[0023] Figure 6 The utility model is a schematic structural diagram of an inner sleeve of a sleeve capable of reducing thermal stress.

[0024] In the figure: 1. upper head; 101. arc-shaped head body; 102. embedded tube; 2. upper joint; 201. external connecting tube body; 202. internal connecting tube body; 3. outer sleeve; 301. first sleeve body; 302. lower extension tube body; 303. first limiting protrusion; 304. limiting slide groove; 305. first inner arc-shaped ring groove; 306. inner arc-shaped limiting ring groove; 307. second inner arc-shaped ring groove; 4. inner sleeve; 401. second sleeve body; 402. outer pressure ring; 403. second limiting protrusion; 404. first outer arc-shaped ring groove; 405. second outer arc-shaped ring groove; 406. limiting spring piece; 407. elastic block; 5. hot melt; 6. shear nail; 7. compensation area. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0026] See also Figure 1-6 The utility model provides an embodiment: a sleeve capable of reducing thermal stress, comprising an outer sleeve 3 and an inner sleeve 4, the outer sleeve 3 comprising a first sleeve body 301, the inner sleeve 4 comprising a second sleeve body 401, an upper joint 2 is arranged at the upper end of the outer sleeve 3, the upper joint 2 comprises an outer connecting tube body 201 and an inner connecting tube body 202, the outer connecting tube body 201 is located at the upper end of the inner connecting tube body 202, the inner connecting tube body 202 is located at the upper end inside the first sleeve body 301, a compensation area 7 is formed inside the first sleeve body 301 along the second sleeve body 401 and the inner connecting tube body 202; an upper head 1 is arranged at the upper end of the upper joint 2, the upper head 1 comprises an arc-shaped head body 101 and an embedded tube 102, the arc-shaped head body 101 is located at the upper end of the embedded tube 102, and the embedded tube 102 is located at the upper end inside the outer connecting tube body 201.

[0027] The outer sleeve 3 includes a first sleeve body 301 having a first inner arc-shaped annular groove 305 at the lower end of the inner surface thereof, and an inner arc-shaped limiting annular groove 306 at the inner surface thereof; a second sleeve body 401 having a first outer arc-shaped annular groove 404 at the upper end of the outer surface thereof, the first outer arc-shaped annular groove 404 corresponding to the first inner arc-shaped annular groove 305 in position, and the first outer arc-shaped annular groove 404 and the first inner arc-shaped annular groove 305 having the same height. A limiting spring piece 406 is arranged in the space between the first outer arc-shaped annular groove 404 and the first inner arc-shaped annular groove 305 on the outside of the second sleeve body 401, and the other end of the limiting spring piece 406 extends into the inner arc-shaped limiting annular groove 306. An elastic block 407 is arranged between the limiting spring piece 406 and the second sleeve body 401. The elastic block 407 can be made of a material with a temperature higher than the melting point of the hot melt component, and the structural position is set by a certain toughness characteristic of the metal. This part of the structure mainly serves as secondary protection; the number of limiting spring pieces 406, elastic blocks 407 and inner arc-shaped limiting annular groove 306 corresponds, and one group or two groups can be arranged.

[0028] The space between the first outer arc-shaped annular groove 404 and the first inner arc-shaped annular groove 305 is filled with a hot melt component 5. The hot melt component 5 is a hot melt material. The hot melt material with a suitable melting point is selected according to the actual application well depth. It can melt when the target melting point is reached, thereby not affecting the movement of each structure.

[0029] Furthermore, a lower extension tube body 302 is provided at the lower end of the first sleeve tube body 301, and a plurality of first limiting protrusions 303 are arranged in an annular array inside the lower extension tube body 302, and a limiting slide groove 304 is formed between two adjacent first limiting protrusions 303; an outer pressure ring 402 is provided at the lower end of the second sleeve tube body 401, and a plurality of second limiting protrusions 403 are arranged in an annular array along the upper end of the outer pressure ring 402 outside the second sleeve tube body 401, and the positions of the second limiting protrusions 403 and the limiting slide groove 304 correspond. This part plays a role of limiting, and when the upper end of the inner sleeve 4 moves toward the compensation area 7, the second limiting protrusions 403 slide upward along the limiting slide groove 304 formed between the first limiting protrusions 303 to prevent the entire structure from being twisted.

[0030] Furthermore, a second inner arc-shaped annular groove 307 is formed on the inner surface of the first sleeve body 301 along the lower end of the first inner arc-shaped annular groove 305, and a second outer arc-shaped annular groove 405 is formed on the outer surface of the second sleeve body 401 along the lower end of the first outer arc-shaped annular groove 404. The second inner arc-shaped annular groove 307 and the second outer arc-shaped annular groove 405 are arranged opposite to each other, and a plurality of shear nails 6 are fixed in the space between the second inner arc-shaped annular groove 307 and the second outer arc-shaped annular groove 405, and both ends of the shear nails 6 are respectively connected to the first sleeve body 301 and the second sleeve body 401. After the temperature in the sleeve rises, the axial component force generated by the thermal stress shears the shear nails 6 between the second inner arc-shaped annular groove 307 and the second outer arc-shaped annular groove 405, and the inner sleeve 4 and the outer sleeve 3 can move automatically.

[0031] Working principle: After high-temperature steam is injected into the thermal recovery well, the temperature inside the casing will increase accordingly, and the hot melt component 5 between the first inner arc-shaped ring groove 305 and the first outer arc-shaped ring groove 404 will gradually melt. Since the elastic block 407 itself is in an elastically stretched state and is installed in the first inner arc-shaped ring groove 305 and the first outer arc-shaped ring groove 404, the hot melt component 5 will pull the limiting spring piece 406 to move toward the inner casing 4 after melting, and one end of the limiting spring piece 406 will detach from the inner arc-shaped limiting ring groove 306.

[0032] The axial component force generated by the thermal stress cuts off the shear nail 6 between the second inner arc-shaped annular groove 307 and the second outer arc-shaped annular groove 405, and the inner sleeve 4 and the outer sleeve 3 can move automatically; the second limiting protrusion strip 403 moves upward along the limiting slide groove 304 formed between the first limiting protrusion strips 303, and the upper end of the inner sleeve 4 moves toward the compensation area 7, offsetting the axial stress generated by the sleeve during the steam injection and breathing process, reducing the deformation caused by the thermal expansion of the sleeve, and reducing the thermal stress to within the yield limit.

[0033] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and 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 be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

Claims

1. A sleeve capable of reducing thermal stress, comprising an outer sleeve (3) and an inner sleeve (4), wherein the outer sleeve (3) comprises a first sleeve body (301), and the inner sleeve (4) comprises a second sleeve body (401); characterized in that: The outer sleeve (3) comprises a first sleeve body (301) having a first inner arc-shaped annular groove (305) formed at the lower end of the inner surface thereof, and an inner arc-shaped limiting annular groove (306) formed on the inner surface of the first inner arc-shaped annular groove (305); A first outer arc-shaped annular groove (404) is formed at the upper end of the outer surface of the second sleeve body (401), the first outer arc-shaped annular groove (404) corresponds to the first inner arc-shaped annular groove (305) in position, and the first outer arc-shaped annular groove (404) and the first inner arc-shaped annular groove (305) have the same height; A limiting spring piece (406) is arranged on the outside of the second sleeve tube body (401) in the space between the first outer arc-shaped annular groove (404) and the first inner arc-shaped annular groove (305), the other end of the limiting spring piece (406) extends into the inner arc-shaped limiting annular groove (306), and an elastic block (407) is arranged between the limiting spring piece (406) and the second sleeve tube body (401); The space between the first outer arc-shaped annular groove (404) and the first inner arc-shaped annular groove (305) is filled with a hot melt component (5).

2. A sleeve capable of reducing thermal stress according to claim 1, characterized in that: A lower extension tube (302) is provided at the lower end of the first sleeve tube (301), and a plurality of first limiting protrusions (303) are arranged in a circular array inside the lower extension tube (302), and a limiting sliding groove (304) is formed between two adjacent first limiting protrusions (303).

3. A sleeve capable of reducing thermal stress according to claim 2, characterized in that: An outer pressure ring (402) is provided at the lower end of the second sleeve body (401), and a plurality of second limiting protrusions (403) are provided in a circular array along the upper end of the outer pressure ring (402) on the outside of the second sleeve body (401), and the second limiting protrusions (403) correspond to the positions of the limiting sliding grooves (304).

4. The sleeve capable of reducing thermal stress according to claim 1, characterized in that: The inner surface of the first sleeve body (301) is provided with a second inner arc-shaped annular groove (307) along the lower end of the first inner arc-shaped annular groove (305), and the outer surface of the second sleeve body (401) is provided with a second outer arc-shaped annular groove (405) along the lower end of the first outer arc-shaped annular groove (404), and the second inner arc-shaped annular groove (307) and the second outer arc-shaped annular groove (405) are arranged opposite to each other.

5. A sleeve capable of reducing thermal stress according to claim 4, characterized in that: A plurality of shear pins (6) are fixed in the space between the second inner arc-shaped annular groove (307) and the second outer arc-shaped annular groove (405), and two ends of the shear pins (6) are respectively connected to the first sleeve body (301) and the second sleeve body (401).

6. The sleeve capable of reducing thermal stress according to claim 1, characterized in that: An upper joint (2) is provided at the upper end of the outer sleeve (3), and the upper joint (2) comprises an outer connecting tube body (201) and an inner connecting tube body (202), wherein the outer connecting tube body (201) is located at the upper end of the inner connecting tube body (202), and the inner connecting tube body (202) is located at the upper end inside the first sleeve tube body (301), and a compensation area (7) is formed inside the first sleeve tube body (301) along the second sleeve tube body (401) and the inner connecting tube body (202).

7. A sleeve capable of reducing thermal stress according to claim 6, characterized in that: An upper end of the upper joint (2) is provided with an upper end cap (1), the upper end cap (1) comprising an arc-shaped end cap body (101) and an embedded tube (102), the arc-shaped end cap body (101) being located at the upper end of the embedded tube (102), and the embedded tube (102) being located at the upper end inside the external connection tube body (201).

Images