A controllable reaming well casing centralizer and related methods

Abstract

The application discloses a casing centralizer for controllable reaming 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 hoop ring, a second hoop ring, a first bow piece and a plurality of second bow pieces. The first bow piece and the plurality of second bow pieces are uniformly distributed between the first hoop ring and the second hoop ring in a circumferential direction. The middle part of the first bow piece and the second bow piece is inwardly bent to form a bent part. The locking device is fixed to the inner side of the first bow piece. The binding rope passes through the locking device. The middle part of the first bow piece is provided with a through hole. The binding rope passes through the through hole from the inner side of the first bow piece and is bound to the bent part of the first bow piece and the plurality of second bow pieces. The locking device can be unlocked to release the binding rope. The casing centralizer improves the centering effect of the casing in the reaming section and the cementing quality, solves the problem of difficult pipe string running in, has a simple structure, low processing cost, is convenient for large-scale popularization and application, and is favorable for improving economic benefits.

Description

A controllable casing centralizer for enlarged wells and related methods Technical Field

[0001] This invention relates to the field of cementing technology for oil and gas wells, and particularly to a casing centralizer and related methods for controllable enlarged wells. Background Technology

[0002] With the further development of oil exploration, the number of deep and ultra-deep wells with small clearance cementing is increasing in order to simplify well structure and reduce well construction costs. Due to the excessively small annular clearance, problems such as well leakage, annular blockage, high construction pump pressure, and thin and unevenly distributed cement sheaths are easily caused. To solve these problems, the large-scale adoption of reaming technology can effectively increase the well diameter and casing annular clearance, reduce construction risks, and improve cementing quality. However, after reaming, using conventional casing centralizers, if designed according to production casing specifications, makes it difficult to ensure casing centering in the reamed section, resulting in lower cementing quality in the reamed section and seriously affecting the development of reaming technology. If designed according to the reamed section specifications, because the outer diameter is much larger than the inner diameter of the upper casing, the downward force when passing through the upper casing is too great, which may cause the tubing string to fail to be lowered. Summary of the Invention

[0003] To enrich the product range of casing centralizers, increase the selection of casing centralization methods, and improve the effect of casing centralization, this invention provides a controllable casing centralizer and related methods for enlarged wells.

[0004] In a first aspect, embodiments of the present invention provide a controllable casing centralizer for enlarged wells, comprising a centralizer body, a binding rope, and a locking device;

[0005] The main body of the straightening device includes a first hoop ring, a second hoop ring, a first bow plate, and several second bow plates;

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

[0007] The middle portions 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 portion 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 more alternative embodiments, the locking device includes a first upper body, a first lower body, a differential pressure 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; in the locked state of the locking device, the first pawl is inserted into the first pawl groove, the differential pressure mandrel is inserted into the center of the first pawl, and the shear pin passes through the gap between the first upper body, the first pawl, and the differential pressure mandrel to fix the first pawl in the first pawl groove.

[0011] The shear pin can be sheared under pressure difference, thereby unlocking the locking device.

[0012] In one or more alternative embodiments, the locking device further includes a sealing ring;

[0013] When the locking device is locked, an air cavity is formed between the lower end of the differential pressure mandrel and the first lower body, and the sealing ring is fitted onto the differential pressure mandrel to seal the air cavity.

[0014] In one or more alternative embodiments, the locking device further includes a limiting nut;

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

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

[0017] The lower end of the first lower body is provided with a first radial through hole, through which the binding rope passes.

[0018] In one or more alternative embodiments, the locking device includes a second upper body, a second lower body, and a temperature control spindle;

[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 locked, the second pawl is inserted into the second pawl groove, and the temperature control spindle is inserted into the center of the second pawl to fix the second pawl in the second pawl groove;

[0020] The temperature-controlled mandrel can contract and deform to unlock the locking device.

[0021] In one or more alternative embodiments, the temperature control mandrel includes 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 in close contact with the inner wall of the support tube;

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

[0024] The support tube can deform under stress.

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

[0026] In one or more alternative embodiments, the temperature control mandrel body is a thermoplastic metal or a shape memory metal.

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

[0028] The lower end of the second lower body is provided with a second radial through hole, through which the binding rope passes.

[0029] In one or more alternative 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; in the locked state of the locking device, 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 by the dissolving liquid, thereby unlocking the locking device.

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

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

[0034] The lower end of the third lower body is provided with a third radial through hole, through which the binding rope passes.

[0035] In one or more alternative embodiments, the controllable enlarged well casing centralizer 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 more alternative embodiments, the binding rope is a steel wire rope.

[0039] In one or more alternative embodiments, the controllable enlarged well casing centralizer further includes a first stop ring and a second stop ring;

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

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

[0042] In a second aspect, embodiments of the present invention provide a casing straightening method for enlarged wells, using the controllable casing straightening device for enlarged wells described in the first aspect, comprising:

[0043] A casing centralizer for controllable enlarged wells is fitted onto the casing;

[0044] Run the casing into the enlarged well until the controllable enlarged well casing centralizer reaches the preset position;

[0045] The locking device is unlocked, the binding rope is released, so that the centralizer body returns to its initial outer diameter and the sleeve is straightened.

[0046] The beneficial effects of the above-mentioned technical solutions provided in the embodiments of the present invention include at least the following:

[0047] The controllable casing centralizer for reaming wells provided in this invention uses a binding rope to bind a first arch plate and several second arch plates, and a locking device to lock the binding rope to the first arch plate. This reduces the outer diameter of the centralizer body to be smaller than the inner diameter of the upper casing, allowing it to be smoothly lowered into the wellbore. When the centralizer reaches the reaming section, the locking device can be unlocked under downhole conditions, releasing the binding rope and restoring the first and second arch plates to their initial shape. The centralizer body returns to its initial maximum outer diameter, thus centering and centralizing the casing in the reaming section. This improves the centering effect of the casing and the cementing quality in the reaming section. Compared with ordinary short-section hydraulic centralizers, it avoids the danger of internal fluid inlet seal failure, solves the problem of the tubing string being difficult to lower, and has a simple structure and low processing cost, making it easy to promote and apply on a large scale and improving economic benefits.

[0048] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0049] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0050] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0051] Figure 1 is a schematic diagram of the structure of the controllable casing centralizer for enlarged wells in the locked state provided in an embodiment of the present invention;

[0052] Figure 2 is a schematic diagram of the structure of the controllable enlarged well casing centralizer in the unlocked state provided in an embodiment of the present invention;

[0053] Figure 3 is a schematic diagram of the structure of the straightening device body provided in an embodiment of the present invention;

[0054] Figure 4 is a schematic diagram of the structure of the straightener body in a bound state provided in an embodiment of the present invention;

[0055] Figure 5 is a top view of the main body of the straightener in a bound state provided in an embodiment of the present invention;

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

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

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

[0059] Figure 9 is a schematic diagram of the structure of the first pawl provided in an embodiment of the present invention.

[0060] In the picture:

[0061] 1 is the body of the stabilizer, 11 is the first hoop ring, 12 is the second hoop ring, 13 is the first bow plate, 131 is the through hole, 14 is the second bow plate, 15 is the bent part, and 16 is the limiting ring;

[0062] 2 is the binding rope;

[0063] 3 is a locking device;

[0064] 31 is a differential pressure locking device, 311 is a first upper body, 3111 is a fourth radial through hole, 3112 is a first pawl groove, 312 is a first lower body, 3121 is a first radial through hole, 3122 is a first pawl, 313 is a differential pressure 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 pawl groove, 322 is a second lower body, 3221 is a second radial through hole, 3222 is a second pawl, 323 is a temperature control spindle, 3231 is a temperature control spindle body, and 3232 is a support tube;

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

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

[0068] 5 is the limit screw;

[0069] 100 is for the sleeve. Detailed Implementation

[0070] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0071] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," "far," "near," "front," and "rear," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0072] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0073] The inventors discovered that while existing conventional short-section hydraulic centralizers can solve the problem of casing centering in reamed wells, their high rigidity makes it difficult to ensure the smooth lowering of the tubing string to the bottom of the well if a large number are installed. Furthermore, the internal fluid inlet of the structure means that if the seals fail later, the integrity of the tubing string cannot be guaranteed. In addition, the manufacturing cost of conventional short-section hydraulic centralizers is relatively high, and large-scale use would significantly increase drilling costs.

[0074] Based on this, embodiments of the present invention provide a casing centralizer and related methods for controllable enlarged wells, which will be described in detail below through specific embodiments.

[0075] Example 1

[0076] This invention provides a controllable casing centralizer for enlarged wells, as shown in Figures 1-5, comprising a centralizer body 1, a binding rope 2, and a locking device 3;

[0077] The body 1 of the straightener includes a first hoop ring 11, a second hoop ring 12, a first bow plate 13 and a plurality of second bow plates 14;

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

[0079] The middle portions 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 portion 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 this embodiment of the invention, referring to Figures 1-5, the first bow plate 13 and several second bow plates 14 are circumferentially evenly distributed between the first hoop ring 11 and the second hoop ring 12. The first bow plate 13, several second bow plates 14, the first hoop ring 11, and the second hoop ring 12 can be integrally stamped into a lantern shape, thereby ensuring uniform force distribution while straightening the casing 100, improving the straightening effect and stability. The middle portions of both the first bow plate 13 and the second bow plate 14 are bent inwards to form bends 15 to accommodate the binding rope 2. This ensures that the binding rope 2 does not contact the casing 100 or the well wall when bound to the straightener body 1, preventing scratches and damage to the casing 100. After the locking device 3 is unlocked, the binding rope 2 remains confined in the groove and will not fall into the wellbore, thus not affecting subsequent construction. The locking device 3 is located inside the first bow piece 13. It can not only prevent the sleeve 100 from being scratched, but also protect the locking device 3 from damage and prevent damage to the locking device 3 from affecting the unlocking performance.

[0082] In this embodiment of the invention, the centralizer body 1 can be compressed to a preset outer diameter using specialized tooling. This preset outer diameter is smaller than the inner diameter of the wellbore, allowing the controllable enlargement well casing centralizer to be smoothly lowered into the wellbore along with the casing 100. Specifically, this can 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. The steel ring has threaded holes and matching bolts evenly distributed on it, equal in number to the first arch plate 13 and several second arch plates 14. During compression, the threaded holes are aligned with the first arch plate 13 and several second arch plates 14, and then the bolts are tightened to compress the first arch plate 13 and the second arch plate 14 until the centralizer body 1 reaches the preset outer diameter. Then, the centralizer body 1 is bound with a binding rope 2 and locked with a locking device 3, so that the first arch plate 13 and several second arch plates 14 are kept in a compressed state, and the centralizer body 1 is stabilized at the preset outer diameter, which is smaller than the minimum diameter of the wellbore, thus allowing it to be smoothly lowered into the wellbore in subsequent operations.

[0083] In this embodiment of the invention, referring to Figures 1, 2, and 4, the locking device 3 is fixed to the inner side of the first bow plate 13 and is a certain distance away from the bent portion 15 of the first bow plate 13. The locking device 3 tightens the binding rope 2, thereby giving the binding rope 2 a certain amount of slack. When the locking device 3 is unlocked, the binding rope 2 is released, the centralizer body 1 is unrestricted, the first bow plate 13 and several second bow plates 14 return to their initial state, and the centralizer body 1 returns to its initial outer diameter. Thus, the controllable casing centralizer for enlarged wells can be used to centralize the casing 100 in the enlarged well section by unlocking the locking device downhole 3, keeping the casing 100 centered.

[0084] In this embodiment of the invention, referring to Figures 1, 2, and 4, 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, and the fixing method can be welding. The limiting ring 16 passes through the fixing ring to be suspended 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, thereby locking the binding rope 2. When the locking device 3 is unlocked, the binding rope 2 is released.

[0085] In this embodiment of the invention, in order to bind the centralizer body 1 more securely, as shown in Figures 3 and 4, the aforementioned through hole 131 can be two circular holes with a diameter 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 inside of the first bow plate 13 and bind the centralizer body 1. Further, the binding rope 2 can be a steel wire rope, and the two ends of the binding rope 2 can be connected with figure-eight steel wire aluminum buckles, and then pressed with a special pliers to fix the two ends of the binding rope 2 together, thereby restricting the recovery and expansion of the centralizer body 1.

[0086] Obviously, the specific material of the binding rope 2 is not limited to the steel wire rope mentioned above, as long as it can achieve the effect of binding and fixing. For details, please refer to the detailed description in the existing technology. Here, no limitation is made. The fixing method at both ends of the binding rope 2 is also not limited to the method of connecting and tightening with steel wire and aluminum buckles. For details, please refer to the detailed description in the existing technology. Here, no limitation is made.

[0087] In one specific embodiment, the locking device 3 can be a differential pressure locking device 31. Referring to Figures 1, 2, 4, 6, and 9, the differential pressure locking device 31 includes a first upper body 311, a first lower body 312, a differential pressure mandrel 313, a sealing ring 315, and a shear pin 314. The first upper body 311 has a first pawl groove 3112 inside, and the end of the first lower body 312 has a first pawl 3122. The first pawl 3122 can be inserted into the first pawl groove 3112. The differential pressure mandrel 313 is installed at the center of the first pawl 3122. The differential pressure mandrel 313 has a shear pin hole. 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, thereby fixing the first pawl 3122 in the first pawl groove 3112, that is, fixing the first upper body 311 and the second lower body 3122 together. A sealing ring 315 is fitted onto the lower part of the differential pressure mandrel 313, forming a sealed air cavity 316 between the lower end of the differential pressure mandrel 313 and the second lower body 322. Therefore, when the differential pressure locking device 31 is locked, the first pawl 3122 is inserted into the first pawl groove 3112, the differential pressure mandrel 313 is installed at the center of the first pawl 3122, and the shear pin 314 passes through the gap between the first upper body 311, the differential pressure mandrel 313 and the first pawl 3122, forming a sealed air cavity 316 between the lower end of the differential pressure mandrel 313 and the first lower body 312. When the controllable enlarged well casing centralizer is lowered to a certain depth 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. At this point, the shear pin 314 is sheared, the mandrel moves, and the first pawl 3122 contracts and deforms inward under the tension of the binding rope 2. The first upper body 311 separates from the first lower body 312, unlocking the device, and the centralizer body 1 returns to its initial maximum outer diameter.

[0088] In one specific embodiment, as shown in FIG6, the differential pressure locking device 31 may further include a limiting nut 317 and a 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 one specific embodiment, referring to Figures 4 and 6, the upper end of the first upper body 311 is provided with a fourth radial through hole 3111, through which the limiting ring 16 can pass to fix the first upper body 311 to the inner side of the first bow piece 13; the lower end of the first lower body 312 is provided with a first radial through hole 3121, through which the binding rope 2 can pass to connect the binding rope 2 to the locking device 3.

[0090] In one specific embodiment, the locking device 3 can be a temperature-controlled locking device 32. Referring to Figures 1, 2, 4, and 7, the temperature-controlled locking device 32 includes a second upper body 321, a second lower body 322, and a temperature-controlled spindle 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, which can be inserted into the second pawl groove 3212. The temperature-controlled spindle 323 is installed at the center of the second pawl 3222, thereby fixing the second pawl 3222 to the second pawl groove 3212, that is, fixing the second lower body 322 to the second upper body 321. The temperature control mandrel 323 includes a temperature control mandrel body 3231 and a support tube 3232 sleeved on the temperature control mandrel body 3231. The outer wall of the temperature control mandrel body 3231 is tightly fitted with the inner wall of the support tube 3232. The temperature control mandrel body 3231 can soften under the action of heating, and the support tube 3232 can deform under force. Therefore, the temperature control mandrel 323 can shrink and deform. When the temperature-controlled locking device 32 is locked, the second pawl 3222 is inserted into the second pawl groove 3212, and the temperature-controlled mandrel 323 is installed at the center of the second pawl 3222. When the controllable reaming well casing centralizer is lowered to a certain depth with the casing 100, the temperature inside the well reaches the softening point of the temperature-controlled mandrel body 3231, the temperature-controlled mandrel body 3231 softens, the support tube 3232 shrinks and deforms, and can no longer support the second pawl 3222. Under the tension of the binding rope 2, the second pawl 3222 shrinks and deforms inward, the second upper body 321 and the second lower body 322 separate, and the centralizer body 1 returns to its initial maximum outer diameter.

[0091] In one specific embodiment, the support tube 3232 can be a thin-walled high-strength aluminum tube or a fiberglass tube, thereby allowing it to deform under the pressure of the second pawl 3222, so that the second pawl 3222 disengages from the second pawl groove 3212 under the tension of the binding rope 2. Obviously, the type of support tube 3232 is not limited to the aforementioned thin-walled high-strength aluminum tube or fiberglass tube; any tube capable of providing support and deformation is acceptable. Specific details can be found in the prior art, and no limitation is made here.

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

[0093] In one specific embodiment, referring to Figures 4 and 7, the upper end of the second upper body 321 is provided with a fifth radial through hole 3211, through which the limiting ring 16 can pass to fix the second upper body 321 to the inner side of the first bow piece 13; the lower end of the second lower body 322 is provided with a second radial through hole 3221, through which the binding rope 2 passes to connect the binding rope 2 to the locking device 3.

[0094] In one specific embodiment, the locking device 3 can be a chemical locking device 33. Referring to Figures 1, 2, 4, and 8, 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, which can be inserted into the third pawl groove 3312. The chemical mandrel 333 is installed at the center of the third pawl 3322, thereby fixing the third pawl 3322 to the third pawl groove 3312, that is, fixing the third lower body 332 to the second upper body 321. The chemical mandrel 333 can dissolve under the action of the dissolving liquid, causing the third pawl 3322 to disengage from the third pawl groove 3312. With the chemical locking device 33 locked, the third pawl 3322 is inserted into the third pawl groove 3312, and the chemical mandrel 333 is inserted into the center of the third pawl 3322. When the controllable enlarged well casing centralizer is fully lowered to the target position with the casing 100, a certain concentration of dissolving liquid can be injected into the wellbore. After standing for a certain period of time, the chemical mandrel 333 can gradually dissolve under the action of the dissolving liquid. When the chemical mandrel 333 dissolves and its strength is insufficient to support the third pawl 3322, the third pawl 3322 will shrink and deform inward under the tension of the binding rope 2, so that the third upper body 331 and the third lower body 332 are separated, thereby unlocking and restoring the centralizer to its initial maximum outer diameter.

[0095] In one specific embodiment, the chemical mandrel 333 is made of a soluble metal, such as a magnesium-aluminum alloy. The specific material type can be reasonably set according to actual needs. For details, please refer to the detailed description in the prior art. Here, it will not be repeated.

[0096] In one specific embodiment, the dissolving solution is a salt solution, such as a KCl solution. The specific type can be reasonably selected according to different soluble metal materials. For details, please refer to the detailed description in the prior art. Here, it will not be repeated.

[0097] In one specific embodiment, referring to Figures 4 and 8, the upper end of the third upper body 331 is provided with a sixth radial through hole 3311, through which the limiting ring 16 can pass to fix the third upper body 331 to the inner side of the first bow piece 13; the lower end of the third lower body 332 is provided with a third radial through hole 3321, through which the binding rope 2 passes to connect the binding rope 2 to the locking device 3.

[0098] In this embodiment of the invention, the locking device 3 can be a differential pressure 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 of the locking devices 3 to obtain a complete controllable casing centralizer for reaming wells. For example, when using the differential pressure locking device 31, the limiting ring 16 passes through the fourth radial through hole 3111, and the binding rope 2 passes through the first radial through hole 3121, thereby installing the differential pressure locking device 31 on the inner side of the first bow plate 13. Therefore, different locking devices 3 can be selected according to the actual conditions of the wellbore. For example, if the temperature change in the wellbore is not significant, the differential pressure locking device 31 or the chemical locking device 33 can be used.

[0099] In one specific embodiment, referring to Figures 1 and 2, the controllable reaming well casing centralizer further 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 limiting screw 5 and is positioned above the first clamping ring 11; the second stop ring 42 can be fixed to the casing 100 by a limiting screw 5 and is positioned below the second clamping ring 12. When the controllable reaming well casing centralizer is installed on the outside of the casing 100, the centralizer body 1 has a short distance from the first stop ring 41 and the second stop ring 42 respectively. When the casing 100 equipped with the controllable reaming well casing centralizer is lowered into the wellbore, the centralizer body 1 is relatively stable under the restraining effect of the first stop ring 41 and the second stop ring 42 and will not slide up and down a large range on the side of the casing 100.

[0100] The controllable casing centralizer for enlarged wells provided in this embodiment of the invention can specifically include the following process for achieving casing centralization:

[0101] After compressing the body 1 of the stabilizer to the preset outer diameter, it is tied and locked by the locking device 3;

[0102] Install the controllable enlarged well casing centralizer on the casing 100 and lower it into the target position of the wellbore along with the casing 100;

[0103] When the locking device 3 is the differential pressure locking device 31, the shear pin 314 is sheared under the action of the pressure difference, causing the first pawl 3122 to disengage from the first pawl groove 3112, the differential pressure locking device 31 is unlocked, the centralizer body 1 returns to its initial maximum outer diameter, and the sleeve 100 is straightened.

[0104] When the locking device 3 is the temperature-controlled locking device 32, the temperature-controlled spindle 323 softens and deforms under the action of heat in the wellbore, causing the second pawl 3222 to disengage from the second pawl groove 3212, the temperature-controlled locking device 32 is unlocked, the centralizer body 1 returns to its initial maximum outer diameter, and the casing 100 is straightened.

[0105] When the locking device 3 is a chemical locking device 33, an appropriate amount of dissolving liquid is injected into the wellbore. After waiting for a preset time period, the chemical mandrel 333 dissolves, causing the third pawl 3322 to disengage from the third pawl groove 3312. The chemical locking device 33 is unlocked, the centralizer body 1 returns to its initial maximum outer diameter, and the casing 100 is centered.

[0106] The controllable casing centralizer provided in this embodiment of the invention binds the first arch plate 13 and several second arch plates 14 with a binding rope 2, and locks the binding rope 2 and the first arch plate 13 together with a locking device 3. This reduces the outer diameter of the centralizer body 1 to be smaller than the inner diameter of the upper casing 100, allowing it to be smoothly lowered into the wellbore. When the centralizer reaches the reaming section, the binding rope 2 is released under downhole conditions by unlocking the locking device 3, allowing the first arch plate 13 and several second arch plates 14 to return to their initial shape, and the centralizer body 1 to return to its initial maximum outer diameter. This centralizes the casing 100 in the reaming section, improving the centering effect of the casing 100 and the cementing quality. Compared with ordinary short-section hydraulic centralizers, it avoids the danger of internal fluid inlet hole seal failure, solves the problem of the pipe string being difficult to lower, and has a simple structure and low processing cost, making it easy to promote and apply on a large scale and improving economic benefits.

[0107] Example 2

[0108] Based on the same inventive concept, this invention also provides a method for casing straightening in enlarged wells, using the controllable casing straightener for enlarged wells described in Embodiment 1, including:

[0109] S101: Install the casing centralizer for controllable enlarged wells onto casing 100;

[0110] S102: Run casing 100 into the enlarged well until the controllable enlarged well casing centralizer reaches the preset well section position;

[0111] S103: Locking device 3 is unlocked, binding rope 2 is released, so that the centralizer body 1 returns to its initial outer diameter and the centralizing sleeve 100 is restored.

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

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

Claims

1. A controllable casing centralizer for enlarged wells, characterized in that, The device includes a centralizer body, a binding rope, and a locking device. The centralizer body comprises a first hoop, a second hoop, a first bow plate, and several second bow plates. The first bow plate and the several second bow plates are evenly distributed circumferentially between the first hoop and the second hoop, and their ends are respectively fixed to the first hoop and the second hoop. The middle portions of the first bow plate and the second bow plate are bent inward to form bends. The locking device is fixed to the inner side of the first bow plate, and the binding rope passes through the locking device. A through hole is provided in the middle of the first bow plate, and the binding rope passes through the through hole from the inner side of the first bow plate and is bound to the bends of the first bow plate and the several second bow plates. The locking device can be unlocked to release the binding rope. The binding rope; the locking device includes a first upper body, a first lower body, a differential pressure mandrel, a shear pin, and a sealing ring; 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; in the locked state of the locking device, the first pawl is inserted into the first pawl groove, the differential pressure mandrel is inserted into the center of the first pawl, and the shear pin passes through the gap between the first upper body, the first pawl, and the differential pressure mandrel to fix the first pawl in the first pawl groove; in the locked state of the locking device, an air cavity is formed between the lower end of the differential pressure mandrel and the first lower body, and the sealing ring is sleeved on the differential pressure mandrel to seal the air cavity; the shear pin can be sheared under the action of the pressure difference to unlock the locking device.

2. The controllable enlargement well casing centralizer according to claim 1, characterized in that, The locking device further includes a limiting nut; the limiting nut can lock the shear pin to fix the shear pin to the first upper body.

3. The controllable enlargement well casing centralizer according to claim 1, characterized in that, The first upper body is fixed to the inner side of the first bow piece; the lower end of the first lower body is provided with a first radial through hole, and the binding rope passes through the first radial through hole.

4. The controllable enlargement well casing centralizer according to claim 1, characterized in that, The locking device includes a second upper body, a second lower body, and a temperature control spindle; 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; in the locked state of the locking device, the second pawl is inserted into the second pawl groove, and the temperature control spindle is inserted into the center of the second pawl to fix the second pawl in the second pawl groove; the temperature control spindle can contract and deform to unlock the locking device.

5. The controllable enlargement well casing centralizer according to claim 4, characterized in that, The temperature control mandrel includes 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 control mandrel body can soften under the action of heating; the support tube can deform under force.

6. The controllable enlargement well casing centralizer according to claim 5, characterized in that, The support tube is a thin-walled high-strength aluminum tube or a glass fiber tube.

7. The controllable enlargement well casing centralizer according to claim 5, characterized in that, The temperature control mandrel body is made of thermoplastic metal or shape memory metal.

8. The controllable enlargement well casing centralizer according to claim 4, characterized in that, The second upper body is fixed to the inner side of the first bow piece; the lower end of the second lower body is provided with a second radial through hole, through which the binding rope passes.

9. The controllable enlargement well casing centralizer according to claim 1, characterized in that, The locking device includes 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; in the 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 to unlock the locking device.

10. The controllable enlargement well casing centralizer according to claim 9, characterized in that, The chemical mandrel is made of a soluble metal.

11. The controllable enlargement well casing centralizer according to claim 9, characterized in that, The third upper body is fixed to the inner side of the first bow piece; the lower end of the third lower body is provided with a third radial through hole, through which the binding rope passes.

12. The controllable enlargement well casing centralizer according to claim 1, characterized in that, It 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.

13. The controllable enlargement well casing centralizer according to claim 1, characterized in that, The binding rope is a steel wire rope.

14. The controllable enlargement well casing centralizer according to claim 1, characterized in that, It also includes a first stop ring and a second stop ring; the first stop ring is disposed above the first clamp ring and can be fixed to the sleeve; the second stop ring is disposed below the second clamp ring and can be fixed to the sleeve.

15. A method for casing centralizing a reaming well, using the controllable casing centralizer as described in any one of claims 1-14, characterized in that, include: The controllable enlarged well casing centralizer is fitted onto the casing; the casing is lowered into the enlarged well until the controllable enlarged well casing centralizer reaches the preset position; the locking device is unlocked, the binding rope is released, so that the centralizer body returns to the initial outer diameter and the casing is straightened.

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