Casing centralizer for controllable reaming well and related method

Abstract

The invention discloses a controllable reaming casing centralizer for a well and a related method. The casing centralizer comprises a centralizer body, a binding rope and a locking device, the centralizer body comprises a first shroud ring, a second shroud ring, a first bow piece and a plurality of second bow pieces; the first bow piece and the second bow pieces are evenly distributed between the first hoop ring and the second hoop ring in the circumferential direction. The middle portions of the first bow piece and the second bow pieces are bent inwards to form bent portions, the locking device is fixed to the inner side of the first bow piece, the binding rope penetrates through the locking device, a through hole is formed in the middle of the first bow piece, and the binding rope penetrates out of the inner side of the first bow piece through the through hole and is bound to the bent portions of the first bow piece and the second bow pieces. The locking device can be unlocked so as to release the binding rope; the casing centralizer improves the centering effect and the well cementation quality of a reaming section casing, solves the problem that a pipe string is difficult to descend, and is simple in structure, low in machining cost, convenient to popularize and apply on a large scale and beneficial to improving economic benefits.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas well cementing, and in particular to a casing centralizer for a controllable hole expansion well and a related method. Background Art

[0002] With the further deepening of oil exploration and development, in order to simplify the wellbore structure and reduce the cost of well construction, the number of small gap cementing in deep wells and ultra-deep wells is increasing. Because the annular space is too small, it is easy to cause problems such as well leakage, annular blockage, high construction pump pressure, thin cement ring and uneven distribution. In order to solve the above problems, the large-scale use of reaming technology can effectively increase the wellbore and casing annular space, reduce construction risks, and improve cementing quality. However, after reaming, conventional casing centralizers are used. If it is designed according to the production casing, it is difficult to ensure the casing centering in the reaming section, resulting in low cementing quality in the reaming section, which seriously affects the development of reaming technology. If it is designed according to the reaming section, since the outer diameter is much larger than the inner diameter of the upper casing, the lowering force is too large when passing through the upper casing, which will cause the pipe string to be unable to be lowered. Summary of the invention

[0003] In order to enrich the product categories of casing centralizers, increase the selection space of casing centralizing methods, and improve the effect of casing centralizing, an embodiment of the present invention provides a casing centralizer for a controllable reaming well and a related method.

[0004] In a first aspect, an embodiment of the present invention provides a casing centralizer for a controllable hole expansion well, comprising a centralizer body, a binding rope and a locking device;

[0005] The centralizer body comprises a first hoop, a second hoop, a first limb and a plurality of second limbs;

[0006] The first bow piece and the plurality of second bow pieces are evenly distributed between the first hoop and the second hoop in the circumferential direction, and two ends of the first bow piece and the second bow piece are fixed to the first hoop and the second hoop respectively;

[0007] The middle parts of the first bow piece and the second bow piece are bent inward to form a bent portion, the locking device is fixed to the inner side of the first bow piece, the binding rope passes through the locking device, a through hole is provided in the middle part of the first bow piece, the binding rope passes through the through hole from the inner side of the first bow piece, and is bound to the bent portions of the first bow piece and the plurality of second bow pieces;

[0008] The locking device can be unlocked to release the binding rope.

[0009] In one or some optional embodiments, the locking device includes a first upper body, a first lower body, a pressure differential mandrel and a shear pin;

[0010] The first upper body is provided with a first pawl groove, and the end of the first lower body is provided with a first pawl; when the locking device is in a locked state, the first pawl is inserted into the first pawl groove, the pressure difference core shaft is inserted into the center of the first pawl, and the shear pin crosses the first upper body, the gap between the first pawl and the pressure difference core shaft to fix the first pawl in the first pawl groove;

[0011] The shear pin can be sheared off under the action of the pressure difference to unlock the locking device.

[0012] In one or some optional embodiments, the locking device further comprises a sealing ring;

[0013] When the locking device is in a locked state, an air cavity is formed between the lower end of the pressure difference core shaft and the first lower body, and the sealing ring is sleeved on the pressure difference core shaft to seal the air cavity.

[0014] In one or some optional embodiments, the locking device further includes a limit nut;

[0015] The limiting nut can lock the shear pin to fix the shear pin to the first upper body.

[0016] In one or some optional embodiments, the first upper body is fixed to the inner side of the first bow piece;

[0017] A first radial through hole is provided at the lower end of the first lower body, and the binding rope passes through the first radial through hole.

[0018] In one or some optional embodiments, the locking device includes a second upper body, a second lower body and a temperature control mandrel;

[0019] The second upper body is provided with a second pawl groove, and one end of the second lower body is provided with a second pawl; when the locking device is in a locked state, the second pawl is inserted into the second pawl groove, and the temperature control core shaft is inserted into the center of the second pawl to fix the second pawl in the second pawl groove;

[0020] The temperature control core shaft can shrink and deform to unlock the locking device.

[0021] In one or some optional embodiments, the temperature control mandrel comprises a temperature control mandrel body and a support tube sleeved on the temperature control mandrel body;

[0022] The outer wall of the temperature control mandrel body is tightly fitted with the inner wall of the support tube;

[0023] The temperature-controlled mandrel body can soften under the action of rising temperature;

[0024] The support tube can be deformed when subjected to force.

[0025] In one or some optional embodiments, the support tube is a thin-walled high-strength aluminum tube or a glass fiber tube.

[0026] In one or some optional embodiments, the temperature control mandrel body is thermoplastic metal or memory metal.

[0027] In one or some optional embodiments, the second upper body is fixed to the inner side of the first bow piece;

[0028] A second radial through hole is provided at the lower end of the second lower body, and the binding rope passes through the second radial through hole.

[0029] In one or some optional embodiments, the locking device includes a third upper body, a third lower body and a chemical mandrel;

[0030] The third upper body is provided with a third pawl groove, and one end of the third lower body is provided with a third pawl; when the locking device is in a locked state, the third pawl is inserted into the third pawl groove, and the chemical mandrel is inserted into the center of the third pawl to fix the third pawl in the third pawl groove;

[0031] The chemical mandrel can be dissolved under the action of a dissolving liquid so as to unlock the locking device.

[0032] In one or some optional embodiments, the chemical mandrel is made of a soluble metal.

[0033] In one or some optional embodiments, the third upper body is fixed to the inner side of the first bow piece;

[0034] A third radial through hole is provided at the lower end of the third lower body, and the binding rope passes through the third radial through hole.

[0035] In one or some optional embodiments, the casing centralizer for controllable hole reaming wells further includes a fixing ring and a limiting ring;

[0036] The fixing ring is fixed to the inner side of the first bow piece, and the limiting ring passes through the fixing ring;

[0037] The limiting ring is connected to the locking device.

[0038] In one or some optional embodiments, the binding rope is a steel wire rope.

[0039] In one or some optional embodiments, the casing centralizer for controllable reaming wells further includes a first stop ring and a second stop ring;

[0040] The first stop ring is disposed above the first hoop and can be fixed to the sleeve;

[0041] The second stop ring is arranged below the second hoop and can be fixed to the sleeve.

[0042] In a second aspect, an embodiment of the present invention provides a casing centralizing method for an expanded well, using the controllable expanded well casing centralizer according to the first aspect, comprising:

[0043] A casing centralizer for a controllable hole expansion well is installed on the casing;

[0044] Lowering the casing into the reaming well until the controllable reaming well casing centralizer reaches a preset position;

[0045] The locking device is unlocked and the binding rope is released to restore the centralizer body to its initial outer diameter and to centralize the casing.

[0046] The beneficial effects of the above technical solution provided in the embodiments of the present invention include at least:

[0047] The casing centralizer for controllable reaming wells provided in an embodiment of the present invention bundles a first bow piece and a plurality of second bow pieces by a bundling rope, and locks the bundling rope and the first bow piece together by a locking device, so that the outer diameter of the centralizer body is reduced to be smaller than the inner diameter of the upper casing, and can be smoothly lowered into the wellbore. When the centralizer reaches the reaming section, the locking device can be unlocked under downhole conditions, thereby releasing the bundling rope, so that the first bow piece and the second bow piece are restored to their initial shape, and the centralizer body is restored to its initial maximum outer diameter, so that the casing is centered and straightened in the reaming section, thereby improving the centering effect and cementing quality of the casing in the reaming section. Compared with ordinary short-section hydraulic centralizers, the risk of failure of the sealing of the inner liquid inlet hole is avoided, and the problem that the pipe string may be difficult to lower is solved. In addition, the structure is simple and the processing cost is low, which is convenient for large-scale promotion and application, and is conducive to improving economic benefits.

[0048] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the accompanying drawings.

[0049] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0051] Figure 1A schematic diagram of the structure of a casing centralizer for a controllable hole-reaming well in a locked state provided in an embodiment of the present invention;

[0052] Figure 2 It is a schematic structural diagram of a casing centralizer for a controllable hole-reaming well in an unlocked state provided in an embodiment of the present invention;

[0053] Figure 3 It is a structural schematic diagram of a centralizer body provided in an embodiment of the present invention;

[0054] Figure 4 It is a structural schematic diagram of a centralizer body in a binding state provided in an embodiment of the present invention;

[0055] Figure 5 It is a schematic diagram of the top view of the structure of the centralizer body in the binding state provided in an embodiment of the present invention;

[0056] Figure 6 It is a schematic diagram of the structure of the pressure differential locking device provided in an embodiment of the present invention;

[0057] Figure 7 It is a schematic diagram of the structure of the temperature control locking device provided in an embodiment of the present invention;

[0058] Figure 8 A schematic diagram of the structure of a chemical locking device provided in an embodiment of the present invention;

[0059] Fig. 9 Schematic diagram of the structure of the first pawl provided in an embodiment of the present invention.

[0060] In the figure:

[0061] 1 is the centralizer body, 11 is the first hoop, 12 is the second hoop, 13 is the first bow piece, 131 is the through hole, 14 is the second bow piece, 15 is the bending part, and 16 is the limit ring;

[0062] 2 is a binding rope;

[0063] 3 is a locking device;

[0064] 31 is a pressure differential locking device, 311 is a first upper body, 3111 is a fourth radial through hole, 3112 is a first ratchet groove, 312 is a first lower body, 3121 is a first radial through hole, 3122 is a first ratchet, 313 is a pressure differential mandrel, 314 is a shear pin, 315 is a sealing ring, 316 is an air cavity, and 317 is a limit nut;

[0065] 32 is a temperature control locking device, 321 is a second upper body, 3211 is a fifth radial through hole, 3212 is a second ratchet groove, 322 is a second lower body, 3221 is a second radial through hole, 3222 is a second ratchet, 323 is a temperature control mandrel, 3231 is a temperature control mandrel body, and 3232 is a support tube;

[0066] 33 is a chemical locking device, 331 is a third upper body, 3311 is a sixth radial through hole, 3312 is a third ratchet groove, 332 is a third lower body, 3321 is a third radial through hole, 3322 is a third ratchet, and 333 is a chemical mandrel;

[0067] 41 is a first stop ring, 42 is a second stop ring;

[0068] 5 is a limit screw;

[0069] 100 is a casing. DETAILED DESCRIPTION

[0070] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0071] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", "far", "near", "front", "back" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0072] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0073] The inventors have found that although the existing ordinary short-section hydraulic centralizer can solve the problem of centering the casing of the expanded well, due to its high rigidity, if a large number of pipes are lowered, it is impossible to ensure that the pipe string is smoothly lowered to the bottom of the well. In addition, there are internal liquid inlet holes in its structure. If the seal fails at a later stage, the integrity of the pipe string cannot be guaranteed. In addition, the processing cost of ordinary short-section hydraulic centralizers is relatively high, and large-scale use will cause a significant increase in drilling costs.

[0074] Based on this, an embodiment of the present invention provides a casing centralizer for a controllable reaming well and a related method, which are described in detail below through specific embodiments.

[0075] Embodiment 1

[0076] The embodiment of the present invention provides a casing centralizer for a controllable hole expansion well, referring to Figure 1-Figure 5 As shown, it includes a centralizer body 1, a binding rope 2 and a locking device 3;

[0077] The centralizer body 1 comprises a first hoop 11, a second hoop 12, a first limb 13 and a plurality of second limbs 14;

[0078] The first bow piece 13 and the plurality of second bow pieces 14 are evenly distributed between the first hoop 11 and the second hoop 12 in the circumferential direction, and two ends of the first bow piece 13 and the second bow piece 14 are fixed to the first hoop 11 and the second hoop 12 respectively;

[0079] The middle parts of the first bow piece 13 and the second bow piece 14 are bent inward to form a bent portion 15, the locking device 3 is fixed to the inner side of the first bow piece 13, the binding rope 2 passes through the locking device 3, a through hole 131 is provided in the middle part of the first bow piece 13, the binding rope 2 passes through the through hole 131 from the inner side of the first bow piece 13, and is bound to the bent portions 15 of the first bow piece 13 and the plurality of second bow pieces 14;

[0080] The locking device 3 can be unlocked to release the binding rope 2 .

[0081] In the embodiment of the present invention, referring to Figure 1-Figure 5As shown, the first fin 13 and the plurality of second fins 14 are evenly distributed between the first hoop 11 and the second hoop 12 in the circumferential direction, and the first fin 13, the plurality of second fins 14, the first hoop 11 and the second hoop 12 can be integrally stamped and formed into a lantern shape, so that the force can be uniformly applied while straightening the casing 100, thereby improving the straightening effect and stability. The middle parts of the first fin 13 and the second fin 14 are both bent inward to form a bending portion 15 to accommodate the binding rope 2, so that the binding rope 2 does not contact the casing 100 and the well wall when it is tied to the straightener body 1, avoiding scratches on the casing 100 and the well wall, and preventing damage to the casing 100; after the locking device 3 is unlocked, the binding rope 2 is still restricted in the groove and will not fall off or fall into the wellbore, which will not affect subsequent construction. The locking device 3 is arranged on the inner side of the first limb 13, which can not only avoid scratching the sleeve 100, but also protect the locking device 3 from being damaged, thereby preventing the locking device 3 from being damaged and affecting the unlocking performance.

[0082] In the embodiment of the present invention, the centralizer body 1 can be compressed to a preset outer diameter by professional tooling, and the preset outer diameter is smaller than the inner diameter of the wellbore, so that the casing centralizer for controllable reaming wells can be smoothly lowered into the wellbore along with the casing 100, which can specifically include: using a steel ring with an inner diameter larger than the outer diameter of the centralizer body 1 to compress the centralizer body 1, and the steel ring is evenly provided with threaded holes and matching bolts equal to the total number of the first bow piece 13 and the plurality of second bow pieces 14. During compression, the threaded holes are aligned with the first bow piece 13 and the plurality of second bow pieces 14, and then the bolts are tightened to compress the first bow piece 13 and the second bow piece 14 until the centralizer body 1 reaches the preset outer diameter, and then the centralizer body 1 is tied with a binding rope 2, and the binding rope 2 is locked with a locking device 3, so that the first bow piece 13 and the plurality of second bow pieces 14 are maintained in a compressed state, and the centralizer body 1 is stabilized at a preset outer diameter, and the preset outer diameter is smaller than the minimum diameter of the wellbore, so that it can be smoothly lowered into the wellbore in subsequent operations.

[0083] In the embodiment of the present invention, referring to Figure 1 , Figure 2 and Figure 4 As shown, the locking device 3 is fixed to the inner side of the first bow piece 13 and has a certain distance from the bent portion 15 of the first bow piece 13. The locking device 3 tightens the binding rope 2 so that the binding rope 2 has a certain relaxation margin. When the locking device 3 is unlocked, the binding rope 2 is released, the stabilizer body 1 loses its restriction, the first bow piece 13 and the plurality of second bow pieces 14 return to their initial state, and the stabilizer body 1 returns to its initial outer diameter. Therefore, the locking device 3 can be unlocked underground to realize the casing centralizer for controllable reaming wells to straighten the casing 100 in the reaming section and keep the casing 100 centered.

[0084] In the embodiment of the present invention, referring to Figure 1 , Figure 2 and Figure 4 As shown, a fixing ring (not shown) and a limiting ring 16 are provided on the inner side of the first bow piece 13. The fixing ring is fixed to the inner side of the first bow piece 13 by welding. The limiting ring 16 passes through the fixing ring to be hoisted on the fixing ring. One end of the locking device 3 is connected to the limiting ring 16, and the other end is connected to the binding rope 2, so that the binding rope 2 is locked. When the locking device 3 is unlocked, the binding rope 2 is released.

[0085] In the embodiment of the present invention, in order to bind the centralizer body 1 more firmly, refer to Figure 3 and Figure 4 As shown, the through holes 131 can be two circular holes with diameters slightly larger than the outer diameter of the binding rope 2. The two ends of the binding rope 2 pass through the two circular holes from the inner side of the first bow piece 13 respectively and then bind the stabilizer body 1. Furthermore, the binding rope 2 can be a steel wire rope. The two ends of the binding rope 2 can be connected by an 8-shaped steel wire aluminum buckle and then compressed by a special pliers-type crimping pliers to fix the two ends of the binding rope 2 together, thereby limiting the recovery and expansion of the stabilizer body 1.

[0086] Obviously, the specific material type of the binding rope 2 is not limited to the above-mentioned steel wire rope, as long as it can achieve the binding and fixing effect, the specific details can be referred to in the prior art, and no limitation is made here. The fixing method of the two ends of the binding rope 2 is also not limited to the method of connecting and pressing the steel wire aluminum buckle, and the specific details can be referred to in the prior art, and no limitation is made here.

[0087] In a specific embodiment, the locking device 3 may be a pressure differential locking device 31, see Figure 1 , Figure 2 , Figure 4 , Figure 6 and Fig. 9As shown, the pressure differential locking device 31 includes a first upper body 311, a first lower body 312, a pressure differential core shaft 313, a sealing ring 315 and a shear pin 314; a first pawl groove 3112 is provided inside the first upper body 311, and a first pawl 3122 is provided at the end of the first lower body 312, and the first pawl 3122 can be inserted into the first pawl groove 3112; the pressure differential core shaft 313 is installed at the center of the first pawl 3122, and the pressure differential core shaft 313 is provided with a shear pin hole, and the shear pin 314 passes through the side wall of the first upper body 311, the pawl gap of the first pawl 3122 and the shear pin hole respectively, so that the first pawl 3122 is fixed in the first pawl groove 3112, that is, the first upper body 311 is fixedly connected to the second lower body 322. The sealing ring 315 is sleeved on the lower part of the pressure differential core shaft 313, so that a sealed air cavity 316 is formed between the lower end of the pressure differential core shaft 313 and the second lower body 322. Therefore, when the pressure differential locking device 31 is locked, the first pawl 3122 is inserted into the first pawl groove 3112, the pressure differential core shaft 313 is installed at the center of the first pawl 3122, and the shear pin 314 crosses the gap between the first upper body 311, the pressure differential core shaft 313 and the first pawl 3122, so that a sealed air cavity 316 is formed between the lower end of the pressure differential core shaft 313 and the first lower body 312. When the casing centralizer for controllable reaming wells goes down to a certain depth along with the casing 100, the hydrostatic column pressure reaches the shear strength of the shear pin 314 and a sufficient pressure difference is formed between the pressure in the air cavity 316 and the pressure in the wellbore, the shear pin 314 is sheared, the core shaft moves, and the first pawl 3122 shrinks and deforms inwardly under the tension of the binding rope 2, the first upper body 311 is separated from the first lower body 312, and unlocking is achieved, and the centralizer body 1 returns to its initial maximum outer diameter.

[0088] In a specific embodiment, referring to Figure 6 As shown, the pressure differential locking device 31 may further include a limiting nut 317 , and the shear pin 314 may be configured as a bolt, so that the limiting nut 317 can lock the end of the shear pin 314 to fix the shear pin 314 to the first upper body 311 .

[0089] In a specific embodiment, referring to Figure 4 and Figure 6 As shown, a fourth radial through hole 3111 is provided at the upper end of the first upper body 311, and the limiting ring 16 can pass through the fourth radial through hole 3111, thereby fixing the first upper body 311 to the inner side of the first bow piece 13; a first radial through hole 3121 is provided at the lower end of the first lower body 312, and the binding rope 2 can pass through the first radial through hole 3121, thereby realizing the connection between the binding rope 2 and the locking device 3.

[0090] In a specific embodiment, the locking device 3 may be a temperature-controlled locking device 32, see Figure 1 , Figure 2 , Figure 4 and Figure 7 As shown, the temperature control locking device 32 includes a second upper body 321, a second lower body 322 and a temperature control core shaft 323; the second upper body 321 is provided with a second pawl groove 3212, and one end of the second lower body 322 is provided with a second pawl 3222, and the second pawl 3222 can be inserted into the second pawl groove 3212; the temperature control core shaft 323 is installed at the center of the second pawl 3222, so as to fix the second pawl 3222 in the second pawl groove 3212, that is, the second lower body 322 is fixedly connected to the second upper body 321. The temperature control core shaft 323 includes a temperature control core shaft body 3231 and a support tube 3232 sleeved on the temperature control core shaft body 3231. The outer wall of the temperature control core shaft body 3231 is tightly fitted with the inner wall of the support tube 3232. The temperature control core shaft body 3231 can soften under the action of rising temperature, and the support tube 3232 can deform under force. Therefore, the temperature control core shaft 323 can shrink and deform. When the temperature control locking device 32 is in the locked state, the second pawl 3222 is inserted into the second pawl groove 3212, and the temperature control core shaft 323 is installed in the center of the second pawl 3222; when the casing centralizer for controllable reaming wells goes down to a certain depth along with the casing 100, after the temperature in the wellbore reaches the softening point of the temperature control core shaft body 3231, the temperature control core shaft body 3231 softens, and the support tube 3232 shrinks and deforms, unable to support the second pawl 3222, and the second pawl 3222 shrinks and deforms inwardly under the tension of the binding rope 2, and the second upper body 321 and the second lower body 322 are separated to achieve unlocking, and the centralizer body 1 returns to its initial maximum outer diameter.

[0091] In a specific embodiment, the support tube 3232 may be a thin-walled high-strength aluminum tube or a glass fiber tube, so that it can be deformed under the pressure of the second pawl 3222, so that the second pawl 3222 is disengaged from the second pawl groove 3212 under the tension of the binding rope 2. Obviously, the type of the support tube 3232 is not limited to the above-mentioned thin-walled high-strength aluminum tube or glass fiber tube, as long as it can play the role of support and deformation, and the details can be referred to the detailed records in the prior art, and no limitation is made here.

[0092] In a specific embodiment, the temperature control core shaft body 3231 can be a thermoplastic metal or a memory metal, so that the temperature control core shaft body 3231 can soften under the action of rising temperature. The specific material type can be reasonably selected according to the temperature range of different wellbores. For details, please refer to the detailed records in the prior art, which will not be repeated here.

[0093] In a specific embodiment, referring to Figure 4 and Figure 7As shown, a fifth radial through hole 3211 is provided at the upper end of the second upper body 321, and the limiting ring 16 can pass through the fifth radial through hole 3211, thereby fixing the second upper body 321 to the inner side of the first bow piece 13; a second radial through hole 3221 is provided at the lower end of the second lower body 322, and the binding rope 2 passes through the second radial through hole 3221, thereby realizing the connection between the binding rope 2 and the locking device 3.

[0094] In a specific embodiment, the locking device 3 may be a chemical locking device 33, see Figure 1 , Figure 2 , Figure 4 and Figure 8 As shown, the chemical locking device 33 includes a third upper body 331, a third lower body 332 and a chemical mandrel 333; the third upper body 331 is provided with a third pawl groove 3312, and one end of the third lower body 332 is provided with a third pawl 3322, and the third pawl 3322 can be inserted into the third pawl groove 3312; the chemical mandrel 333 is installed at the center of the third pawl 3322, so that the third pawl 3322 is fixed to the third pawl groove 3312, that is, the third lower body 332 is fixedly connected to the second upper body 321. The chemical mandrel 333 can be dissolved under the action of the dissolving liquid, so that the third pawl 3322 is separated from the third pawl groove 3312. When the chemical locking device 33 is in the locked state, the third pawl 3322 is inserted into the third pawl groove 3312, and the chemical core shaft 333 is inserted into the center of the third pawl 3322; when the casing straightener for controllable reaming wells is completely lowered to the target position along with the casing 100, a certain concentration of solvent can be injected into the wellbore and left to stand for a certain period of time. The chemical core shaft 333 can gradually dissolve under the action of the solvent. When the chemical core shaft 333 dissolves and its strength is insufficient to support the third pawl 3322, the third pawl 3322 will shrink and deform inwardly under the tension of the binding rope 2, so that the third upper body 331 is separated from the third lower body 332, thereby achieving unlocking and the straightener returns to its initial maximum outer diameter.

[0095] In a specific embodiment, the material of the chemical core shaft 333 is a soluble metal, for example, it can be a magnesium-aluminum alloy. The specific material type can be reasonably set according to actual needs. For details, please refer to the detailed records in the prior art, which will not be repeated here.

[0096] In a specific embodiment, the dissolving liquid is a salt solution, for example, it can be a KCl solution, and its specific type can be reasonably selected according to different soluble metal materials. For details, please refer to the detailed records in the prior art, which will not be repeated here.

[0097] In a specific embodiment, referring to Figure 4 and Figure 8As shown, a sixth radial through hole 3311 is provided at the upper end of the third upper body 331, and the limiting ring 16 can pass through the sixth radial through hole 3311, thereby fixing the third upper body 331 to the inner side of the first bow piece 13; a third radial through hole 3321 is provided at the lower end of the third lower body 332, and the binding rope 2 passes through the third radial through hole 3321, thereby realizing the connection between the binding rope 2 and the locking device 3.

[0098] In the embodiment of the present invention, the locking device 3 can be a pressure differential locking device 31, a temperature control locking device 32 or a chemical locking device 33. The centralizer body 1 and the binding rope 2 can be combined with any type of locking device 3 to obtain a complete casing centralizer for a controllable reaming well. For example, when the pressure differential locking device 31 is used, the limit ring 16 passes through the fourth radial through hole 3111, and the binding rope 2 passes through the first radial through hole 3121, so that the pressure differential locking device 31 is installed on the inner side of the first bow piece 13. Therefore, different locking devices 3 can be selected according to the actual situation of the wellbore. For example, if the temperature change in the wellbore is not obvious enough, the pressure differential locking device 31 or the chemical locking device 33 can be used.

[0099] In a specific embodiment, referring to Figure 1 and Figure 2 As shown, the casing centralizer for controllable reaming wells also includes a first stop ring 41 and a second stop ring 42. The first stop ring 41 can be fixed to the casing 100 by a stop screw 5 and is arranged above the first hoop 11; the second stop ring 42 can be fixed to the casing 100 by a stop screw 5 and is arranged below the second hoop 12. When the casing centralizer for controllable reaming wells is installed on the outside of the casing 100, the centralizer body 1 is at a short distance from the first stop ring 41 and the second stop ring 42 respectively. When the casing 100 equipped with the casing centralizer for controllable reaming wells is lowered into the wellbore, the centralizer body 1 is relatively stable under the limiting effect of the first stop ring 41 and the second stop ring 42, and will not slide up and down in a large range on the side of the casing 100.

[0100] The casing centralizer for a controllable reaming well provided in an embodiment of the present invention can realize the process of centralizing the casing 100 by:

[0101] Compress the centralizer body 1 to a preset outer diameter and then tie it up, and lock the tying rope 2 by the locking device 3;

[0102] A casing centralizer for a controllable hole expansion well is installed on the casing 100 and lowered into the target position of the wellbore along with the casing 100;

[0103] When the locking device 3 is a pressure differential locking device 31, the shear pin 314 is sheared off under the action of the pressure difference, so that the first pawl 3122 is disengaged from the first pawl groove 3112, the pressure differential locking device 31 is unlocked, the centralizer body 1 restores the initial maximum outer diameter, and the casing 100 is straightened;

[0104] When the locking device 3 is a temperature-controlled locking device 32, the temperature-controlled mandrel 323 softens and deforms under the action of the heat in the wellbore, so that the second pawl 3222 disengages from the second pawl groove 3212, the temperature-controlled locking device 32 is unlocked, and the centralizer body 1 restores the initial maximum outer diameter to centralize the casing 100;

[0105] When the locking device 3 is a chemical locking device 33, an appropriate amount of dissolving liquid is injected into the wellbore, and the chemical core shaft 333 is dissolved after a preset period of time, so that the third pawl 3322 disengages from the third pawl groove 3312, the chemical locking device 33 is unlocked, and the centralizer body 1 restores the initial maximum outer diameter to centralize the casing 100.

[0106] The casing centralizer for controllable reaming wells provided in the embodiment of the present invention bundles the first bow piece 13 and the plurality of second bow pieces 14 by means of the bundling rope 2, and locks the bundling rope 2 and the first bow piece 13 together by means of the locking device 3, so that the outer diameter of the centralizer body 1 is reduced to be smaller than the inner diameter of the upper casing 100, and the centralizer body 1 can be smoothly lowered into the wellbore. When the centralizer reaches the reaming section, the bundling rope 2 is unlocked and released by the locking device 3 under downhole conditions, so that the first bow piece 13 and the plurality of second bow pieces 14 are restored to their initial shapes, and the centralizer body 1 restores its initial maximum outer diameter, so that the casing 100 is centered and straightened in the reaming section, thereby improving the centering effect and cementing quality of the casing 100 in the reaming section. Compared with the ordinary short-section hydraulic centralizer, the risk of failure of the sealing of the inner liquid inlet hole is avoided, and the problem that the pipe string may be difficult to lower is solved. The centralizer has a simple structure and a low processing cost, which is convenient for large-scale promotion and application, and is conducive to improving economic benefits.

[0107] Embodiment 2

[0108] Based on the same inventive concept, an embodiment of the present invention further provides a casing centralizing method for an expanded well, using the controllable expanded well casing centralizer described in Embodiment 1, comprising:

[0109] S101: Installing a casing centralizer for a controllable hole expansion well on the casing 100;

[0110] S102: lowering the casing 100 into the reaming well until the casing centralizer for the controllable reaming well reaches a preset well section position;

[0111] S103 : The locking device 3 is unlocked and the binding rope 2 is released to restore the centralizer body 1 to the initial outer diameter and to centralize the casing 100 .

[0112] In the embodiment of the present invention, the casing straightening method for reaming wells corresponds to the casing straightening device for controllable reaming wells described in Example 1. The specific implementation process can refer to the process of implementing casing straightening using the casing straightening device for controllable reaming wells in Example 1, which will not be repeated here.

[0113] Obviously, various changes and modifications may be made to the present invention by those skilled in the art without departing from the spirit and scope of the present invention. The present disclosure is not limited to the precise structure described above and shown in the accompanying drawings, and various changes and modifications may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims. Thus, if these changes and modifications of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these changes and modifications.

Claims

1. A casing centralizer for a controllable hole expansion well, characterized in that: It includes a centralizer body, a lashing rope and a locking device; The centralizer body comprises a first hoop, a second hoop, a first limb and a plurality of second limbs; The first bow piece and the plurality of second bow pieces are evenly distributed between the first hoop and the second hoop in the circumferential direction, and two ends of the first bow piece and the second bow piece are fixed to the first hoop and the second hoop respectively; The middle parts of the first bow piece and the second bow piece are bent inward to form a bent portion, the locking device is fixed to the inner side of the first bow piece, the binding rope passes through the locking device, a through hole is provided in the middle part of the first bow piece, the binding rope passes through the through hole from the inner side of the first bow piece, and is bound to the bent portions of the first bow piece and the plurality of second bow pieces; The locking device can be unlocked to release the binding rope.

2. The casing centralizer for controllable hole expansion according to claim 1, characterized in that: The locking device comprises a first upper body, a first lower body, a pressure difference mandrel and a shear pin; The first upper body is provided with a first pawl groove, and the end of the first lower body is provided with a first pawl; when the locking device is in a locked state, the first pawl is inserted into the first pawl groove, the pressure difference core shaft is inserted into the center of the first pawl, and the shear pin crosses the first upper body, the gap between the first pawl and the pressure difference core shaft to fix the first pawl in the first pawl groove; The shear pin can be sheared off under the action of the pressure difference to unlock the locking device.

3. The casing centralizer for controllable hole expansion according to claim 2, characterized in that: The locking device also includes a sealing ring; When the locking device is in a locked state, an air cavity is formed between the lower end of the pressure difference core shaft and the first lower body, and the sealing ring is sleeved on the pressure difference core shaft to seal the air cavity.

4. The casing centralizer for controllable hole expansion according to claim 3, characterized in that: The locking device also includes a limiting nut; The limiting nut can lock the shear pin to fix the shear pin to the first upper body.

5. The casing centralizer for controllable hole expansion according to claim 2, characterized in that: The first upper body is fixed to the inner side of the first bow piece; A first radial through hole is provided at the lower end of the first lower body, and the binding rope passes through the first radial through hole.

6. The casing centralizer for controllable hole expansion according to claim 1, characterized in that: The locking device comprises a second upper body, a second lower body and a temperature control mandrel; The second upper body is provided with a second pawl groove, and one end of the second lower body is provided with a second pawl; when the locking device is in a locked state, the second pawl is inserted into the second pawl groove, and the temperature control core shaft is inserted into the center of the second pawl to fix the second pawl in the second pawl groove; The temperature control core shaft can shrink and deform to unlock the locking device.

7. The casing centralizer for controllable hole expansion according to claim 6, characterized in that: The temperature control mandrel comprises a temperature control mandrel body and a support tube sleeved on the temperature control mandrel body; The outer wall of the temperature control mandrel body is tightly fitted with the inner wall of the support tube; The temperature-controlled mandrel body can soften under the action of rising temperature; The support tube can be deformed when subjected to force.

8. The casing centralizer for controllable hole expansion according to claim 7, characterized in that: The support tube is a thin-wall high-strength aluminum tube or a glass fiber tube.

9. The casing centralizer for controllable hole expansion according to claim 7, characterized in that: The temperature control core shaft body is made of thermoplastic metal or memory metal.

10. The casing centralizer for controllable hole expansion according to claim 6, characterized in that: The second upper body is fixed to the inner side of the first bow piece; A second radial through hole is provided at the lower end of the second lower body, and the binding rope passes through the second radial through hole.

11. The casing centralizer for controllable hole expansion according to claim 1, characterized in that: The locking device comprises a third upper body, a third lower body and a chemical mandrel; The third upper body is provided with a third pawl groove, and one end of the third lower body is provided with a third pawl; when the locking device is in a locked state, the third pawl is inserted into the third pawl groove, and the chemical mandrel is inserted into the center of the third pawl to fix the third pawl in the third pawl groove; The chemical mandrel can be dissolved under the action of a dissolving liquid so as to unlock the locking device.

12. The casing centralizer for controllable hole expansion according to claim 11, characterized in that: The material of the chemical mandrel is soluble metal.

13. The casing centralizer for controllable hole expansion according to claim 11, characterized in that: The third upper body is fixed to the inner side of the first bow piece; A third radial through hole is provided at the lower end of the third lower body, and the binding rope passes through the third radial through hole.

14. The casing centralizer for controllable hole expansion according to claim 1, characterized in that: Also includes a fixing ring and a limiting ring; The fixing ring is fixed to the inner side of the first bow piece, and the limiting ring passes through the fixing ring; The limiting ring is connected to the locking device.

15. The casing centralizer for controllable hole expansion according to claim 1, characterized in that: The binding rope is a steel wire rope.

16. The casing centralizer for controllable hole expansion according to claim 1, characterized in that: Also includes a first stop ring and a second stop ring; The first stop ring is disposed above the first hoop and can be fixed to the sleeve; The second stop ring is arranged below the second hoop and can be fixed to the sleeve.

17. A method for centralizing casing for an expanded well, using the controllable expanded well casing centralizer according to any one of claims 1 to 16, characterized in that: include: A casing centralizer for a controllable hole expansion well is installed on the casing; Lowering the casing into the reaming well until the controllable reaming well casing centralizer reaches a preset position; The locking device is unlocked and the binding rope is released to restore the centralizer body to its initial outer diameter and to centralize the casing.

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