A casing centralizer with pipe diameter adjusting function

Abstract

The application discloses a casing centralizer with pipe diameter adjusting function, and relates to the technical field of oil and gas drilling engineering equipment, which comprises two fixed rings which are symmetrically distributed left and right, the outer surfaces of the fixed rings are provided with a plurality of fixed seats which are equidistantly arranged along the circumferences of the fixed rings, the fixed seats are all rotatably connected with connecting plates, an elastic plate is arranged between the left and right connecting plates in the horizontal direction, and the two ends of each elastic plate are rotatably connected with the adjacent two connecting plates. The application drives the screw rod and the fixed pipe to be in threaded transmission by rotating the adjusting bolt, the distance between the two fixed rings is accurately controlled, the annular support frame formed by the connecting plates and the elastic plates is caused to have controllable radial deformation, stepless adjustment of the support outer diameter is realized, different wellbore sizes are accurately matched, the problem of insufficient support or difficulty in running of the fixed-size centralizer is overcome, and the casing is efficiently centered, so that the foundation for forming a uniform cement sheath is laid.

Description

Technical Field

[0001] This invention relates to the field of oil and gas drilling equipment technology, and in particular to a casing centralizer with pipe diameter adjustment function. Background Technology

[0002] As a key auxiliary device in the casing running-in stage of drilling operations, the casing centralizer plays an important supporting role in low-carbon mining. By centering the casing during casing running into the wellbore, it can avoid equipment wear caused by friction between the casing and the well wall, and ensure uniform filling of cement slurry in the annular space outside the casing. This effectively improves cementing quality, ensures wellbore integrity, and extends well life. It reduces subsequent leakage and rework problems caused by substandard cementing from the source, reduces resource waste and additional carbon emissions, and is an indispensable technical link in the low-carbon mining system.

[0003] However, existing casing centralizers generally suffer from a "fixed size" design flaw, making it difficult to adapt to the pipe diameter requirements at different stages of drilling operations. On the one hand, different sections of the same well (such as surface casing sections and technical casing sections) have different wellbore diameters, requiring the replacement of centralizers of different specifications to meet the centering support requirements. On the other hand, even within the same section, the wellbore diameter may deviate locally due to fluctuations in drilling processes. Fixed-size centralizers cannot flexibly adjust the support radius, easily leading to insufficient local support. This can cause casing deviation, affecting the uniformity of cement slurry distribution and reducing cementing quality. In severe cases, it can lead to direct contact between the casing and the wellbore, exacerbating wear and increasing the risk of wellbore leakage later on. This not only violates the energy-saving and consumption-reducing concept of low-carbon mining but may also shorten the service life of oil wells and increase operation and maintenance costs.

[0004] Based on the above situation, there is an urgent need to develop a casing centralizer that can flexibly adapt to different wellbore sizes in order to improve its adaptability and centralizing effect in complex well conditions, and further contribute to the green and efficient development of oil and gas fields. Summary of the Invention

[0005] In order to overcome the shortcomings of existing casing centralizers, which are difficult to adapt to different well sections or well diameter changes due to their fixed size, resulting in poor centering effect and poor cementing quality, this invention provides a casing centralizer with pipe diameter adjustment function.

[0006] The technical implementation of the present invention is as follows: a casing centralizer with pipe diameter adjustment function includes two fixed rings symmetrically distributed on the left and right. A plurality of fixed seats are equally spaced along the circumference of the outer surface of each fixed ring. A connecting plate is rotatably connected to each fixed seat. An elastic plate is provided between the two connecting plates in the horizontal direction. The two ends of each elastic plate are rotatably connected to the two adjacent connecting plates respectively. An adjustment component for adapting to different wellbore diameters is provided between the two fixed rings.

[0007] Optionally, the adjustment assembly includes an adjustment bolt symmetrically rotatably connected to the left fixed ring, and a fixed tube symmetrically distributed with the adjustment bolt along the horizontal direction fixed to the right fixed ring. Each adjustment bolt has a screw fixed to the side near the fixed tube, and each screw is threadedly connected to the adjacent fixed tube.

[0008] Optionally, each fixing ring has a plurality of grooves evenly spaced along its circumference, the number of grooves being the same as the number of connecting plates, and each groove is provided with a limiting component to ensure the stability of the connecting plate.

[0009] Optionally, the limiting component includes sliders that are slidably connected in the groove, and each slider is provided with a connecting rod between itself and the adjacent connecting plate. The two ends of the connecting rod are rotatably connected to the adjacent connecting plate and slider, respectively.

[0010] Optionally, each left fixing ring has a limiting ring fixedly connected to the side near the adjusting bolt. Each adjusting bolt has a locking rod that slides radially inside it. Each locking rod is connected to the inner wall of the adjacent adjusting bolt with a spring piece. Each locking rod has a locking part at the end near the limiting ring. Each locking part slides horizontally inside the adjacent adjusting bolt and engages with the adjacent limiting ring.

[0011] Optionally, each limiting ring has uniformly distributed grooves on its end face along the circumference for engaging with the locking part.

[0012] Optionally, each retaining ring is provided with a placement hole, and each placement hole is machined with an internal thread for installing and fixing the connecting parts.

[0013] Optionally, each placement hole is equipped with a connecting ring, the outer side of which is machined with locking threads that match the internal threads of the placement hole.

[0014] The beneficial effects of this invention are as follows: This invention precisely controls the distance between the two fixed rings by rotating the adjusting bolt to drive the relative movement of the screw and the fixed pipe, thereby causing the annular support frame composed of the connecting plate and the elastic plate to produce controllable radial deformation; this design realizes stepless adjustment of the outer diameter of the centralizer support, which can accurately match different wellbore sizes from vertical wells to horizontal wells, effectively overcoming the problem of insufficient support or difficulty in running in fixed-size centralizers due to improper gaps with the well wall, ensuring efficient centering of the casing throughout the complex wellbore, and laying a solid foundation for the formation of a uniform cement sheath.

[0015] This invention integrates an automatic locking mechanism driven by a spring. Once adjusted to the target diameter, the locking rod automatically engages with the circumferential groove of the limiting ring under the restoring force of the spring, forming a mechanical interlock. This fundamentally prevents the adjusting bolt from reversing and the support from failing due to severe downhole vibrations. Simultaneously, the four-bar linkage constituting the slider and connecting rod precisely converts the swing of the connecting plate into linear motion and limits its stroke, eliminating unexpected deflection and ensuring the dynamic stability of the entire adjustment process and operating state, greatly improving the safety and reliability of downhole operations.

[0016] This invention innovatively adopts a detachable solution with a locking thread connecting ring and a fixed ring with internal thread engagement. By selecting connecting rings of different inner diameters, the centralizer can be quickly and securely installed on casings of various outer diameters, solving the limitation that a single centralizer can only be adapted to one type of casing. This modular design significantly improves the product's versatility and inventory utilization, reduces procurement and management costs, and its assembly process is simple, requiring no special tools, greatly improving on-site operation efficiency and perfectly meeting the requirements of low-carbon mining for resource optimization and operational convenience. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0018] Figure 2 This is a three-dimensional structural diagram of the components such as the fixing base, connecting plate, and elastic plate of the present invention.

[0019] Figure 3 This is a three-dimensional structural diagram of the connecting rod, fixing ring, and slider components of the present invention.

[0020] Figure 4 This is a three-dimensional structural diagram of the fixing ring and connecting rod of the present invention.

[0021] Figure 5 This is a three-dimensional structural diagram of the fixing ring and the limiting ring of the present invention.

[0022] Figure 6 This is a three-dimensional structural diagram of the components such as the limiting ring, locking rod, and spring sheet of the present invention.

[0023] Figure 7 This is a three-dimensional structural diagram of the locking rod, locking part, and limiting ring of the present invention.

[0024] Figure 8 A three-dimensional cross-sectional view of the connecting ring and the fixing ring of the present invention.

[0025] Wherein: 101-fixed ring, 102-fixed seat, 103-placement hole, 104-connecting plate, 105-elastic plate, 106-fixed tube, 107-screw, 108-adjusting bolt, 201-connecting rod, 202-slide groove, 203-slider, 301-limiting ring, 302-locking rod, 3021-locking part, 303-spring piece, 401-connecting ring, 402-locking groove. Detailed Implementation

[0026] Although the invention may be described with respect to specific applications or industries, those skilled in the art will recognize its broader applicability. Those skilled in the art will understand that terms such as "above," "below," "upward," "downward," etc., are used to describe the drawings and not to indicate a limitation on the scope of the invention as defined by the appended claims. Any numerical designations such as "first" or "second" are merely illustrative and not intended to limit the scope of the invention in any way.

[0027] Example 1: A casing centralizer with pipe diameter adjustment function, such as Figure 1 and Figure 2 As shown, the structure includes two symmetrically distributed fixed rings 101, which serve as the core support carrier of the overall structure. They are used to install various functional components and cooperate with the casing to achieve coaxial positioning. Each fixed ring 101 has a plurality of fixed seats 102 evenly spaced along its circumference on its outer surface. Each fixed seat 102 is rotatably connected to a connecting plate 104, allowing the connecting plate 104 to swing around the fixed seat 102 within a certain angle. An elastic plate 105 is provided between the two connecting plates 104 in the horizontal direction. The two ends of each elastic plate 105 are rotatably connected to the two adjacent connecting plates 104, thereby forming a radially expandable annular support frame. An adjustment component is provided between the two fixed rings 101 to adapt to different wellbore diameters. By changing the distance between the two fixed rings 101, the annular support frame is driven to produce radial deformation, thereby achieving pipe diameter adjustment.

[0028] Specifically, the adjustment assembly includes an adjusting bolt 108 symmetrically rotatably connected to the left fixed ring 101, used to receive external operating force, such as the tightening force of a hex wrench, and is the power input component for the adjustment action; the right fixed ring 101 is fixedly connected to fixed tubes 106 symmetrically distributed horizontally corresponding to the adjusting bolts 108, and each adjusting bolt 108 is fixedly connected to a screw 107 on the side near the fixed tube 106, serving as a core transmission component, transmitting power through threaded engagement with the fixed tube 106, and each screw 107 is threadedly connected to the adjacent fixed tube 106. During operation, rotating the adjusting bolt 108 can drive the screw 107 to screw into or out of the fixed tube 106, thereby bringing the two fixed rings 101 closer or farther apart.

[0029] like Figure 3 and Figure 4 As shown, specifically, each fixed ring 101 has a plurality of grooves 202 evenly spaced along its circumference. The number of grooves 202 is the same as the number of connecting plates 104. Each groove 202 is provided with a limiting component to ensure the stability of the connecting plate 104. This component is used to constrain the swing trajectory of the connecting plate 104 during the adjustment process, prevent it from deflecting unexpectedly, and ensure the stability of the action.

[0030] Specifically, the limiting component includes sliders 203 slidably connected within the slide groove 202. Each slider 203 is connected to an adjacent connecting plate 104 by a connecting rod 201, the two ends of which are rotatably connected to the adjacent connecting plate 104 and slider 203, respectively. This four-bar linkage converts the swing of the connecting plate 104 into linear motion of the slider 203 within the slide groove 202, achieving precise guidance and limiting of the swing trajectory of the connecting plate 104.

[0031] like Figures 5-7 As shown, specifically, each of the left fixed rings 101 has a limiting ring 301 fixedly connected to the side near the adjusting bolt 108. Each adjusting bolt 108 has a locking rod 302 slidably connected radially within it, giving the locking rod 302 the freedom to move toward or away from the limiting ring 301. Each locking rod 302 is connected to the inner wall of the adjacent adjusting bolt 108 by a spring piece 303, which provides elastic force so that the locking rod 302 always receives a thrust toward the limiting ring 301. Each locking rod 302 has a locking part 3021 at the end near the limiting ring 301. Each locking part 3021 slides horizontally within the adjacent adjusting bolt 108, and its function is to finally cooperate with the limiting ring 301 to achieve mechanical interlocking.

[0032] Specifically, each limiting ring 301 has evenly distributed grooves on its end face along the circumference, which are used to engage with the locking part 3021. When the centralizer is adjusted to the target diameter, the locking part 3021 automatically engages with the corresponding groove under the push of the spring piece 303. Through this engagement, the locking rod 302 is radially limited, thereby preventing the adjusting bolt 108 from rotating, and finally completing the reliable locking of the overall adjustment state.

[0033] This embodiment is used to adapt the centralizer support radius to the wellbore diameter. The specific process is as follows: When it is necessary to adjust the outer diameter of the stabilizer support according to the wellbore diameter, follow these steps: The operator inserts a hex wrench into the operating hole of the adjusting bolt 108, and the end of the wrench pushes the locking rod 302 to move radially inward along the adjusting bolt 108, causing the locking part 3021 to disengage from the groove of the limiting ring 301, thus completing the mechanical unlocking of the adjusting bolt 108; during this process, the locking rod 302 compresses the spring 303 to produce elastic deformation, which stores elastic force for subsequent reset.

[0034] Turning the hex wrench clockwise or counterclockwise drives the adjusting bolt 108 and the screw 107, which are coaxially fixed, to rotate synchronously. Since the screw 107 and the fixed tube 106 are engaged by threads, the rotational motion is converted into the horizontal movement of the right-side fixed ring 101.

[0035] When the right fixed ring 101 moves to the right, the distance between the two fixed rings 101 increases, and the connecting plate 104 is forced to deflect inward through the fixed seat 102, which causes the annular support frame formed by the elastic plate 105 to contract radially to adapt to the smaller wellbore.

[0036] When the right fixed ring 101 moves to the left, the distance between the two fixed rings 101 decreases, and the connecting plate 104 deflects outward under the drive of the mechanism, forcing the elastic plate 105 to expand radially to accommodate a larger wellbore.

[0037] After adjusting to the target diameter, remove the hex wrench. The restoring force of the spring 303 pushes the locking rod 302 and the locking part 3021 to reset, so that they are engaged in the corresponding slot on the limiting ring 301, realizing automatic mechanical locking and effectively preventing the adjustment bolt 108 from rotating due to downhole vibration.

[0038] Throughout the adjustment process, the deflection of the connecting plate 104 drives the slider 203 to slide within the groove 202 via the connecting rod 201. The length of the groove 202 limits the maximum sliding stroke of the slider 203, indirectly constraining the maximum swing angle of the connecting plate 104. This four-bar linkage precisely constrains the swing of the connecting plate 104 to a predetermined trajectory and limits its maximum deflection angle, ensuring the smoothness of the adjustment process and the overall stability of the support structure.

[0039] Example 2: Figure 1 and Figure 8 As shown, specifically, each fixing ring 101 is provided with a placement hole 103, and each placement hole 103 is machined with an internal thread for assembly with external connecting components, so as to realize the integrated installation of the centralizer in the sleeve string.

[0040] Each placement hole 103 is equipped with a connecting ring 401, the outer side of which is machined with a locking thread 402 that matches the internal thread of the placement hole 103. By screwing the connecting ring 401, the locking thread 402 and the internal thread of the placement hole 103 are tightly fitted together, so that the centralizer can be firmly installed on the casing body of different outer diameter specifications, thereby achieving effective centralization and centering support for casings of different sizes.

[0041] This embodiment is used to realize the assembly and adaptation of the centralizer with sleeves of different outer diameters. It is based on the detachable connecting ring 401. The specific process is as follows: measure the outer diameter of the matching tube to be installed and compare it with the inner diameter of the placement hole 103 in the fixing ring 101, and adapt it in two scenarios.

[0042] Scenario 1 (Outer diameter of the sleeve matches the inner diameter of the placement hole 103): If the outer diameter of the sleeve is equal to the inner diameter of the placement hole 103, the placement hole 103 of the stabilizer is directly fitted onto the outer wall of the sleeve. Initial fixation is achieved by the interference fit between the inner wall of the placement hole 103 and the outer wall of the sleeve. Further positioning is achieved by the sleeve coupling.

[0043] Scenario 2 (outer diameter of the sleeve is smaller than the placement hole 103): If the outer diameter of the sleeve is smaller than the inner diameter of the placement hole 103, a connecting ring 401 with an inner diameter that matches the outer diameter of the sleeve and an outer diameter that matches the inner diameter of the placement hole 103 should be selected.

[0044] Insert the selected connecting ring 401 into one end of the sleeve and move it to the position corresponding to the centralizer placement hole 103. Rotate the connecting ring 401 clockwise so that the locking thread 402 on its outer side engages with the internal thread of the placement hole 103 until the end face of the connecting ring 401 is in contact with the stepped surface of the placement hole 103. Apply a preset torque with a torque wrench to ensure that the connecting ring 401 and the fixing ring 101 are firmly connected without relative rotation.

[0045] Move the centralizer with the connecting ring 401 assembled along the casing axis to the designed installation position (usually 1-2 centralizers are installed on each casing, with a spacing of 5-10m). If further fixation is required, anaerobic adhesive can be applied to the gap between the connecting ring 401 and the outer wall of the casing to enhance the sealing and connection strength and prevent the centralizer from sliding along the casing axis.

[0046] After assembly, the stability of the centralizer is verified by pushing it by hand: if the centralizer has no radial sway or axial movement, and the connecting ring 401 is not loose, it is considered to be suitable and qualified; if there is a gap, the connecting ring 401 with a smaller inner diameter or additional sealing gaskets are required to ensure that the centralizer is coaxial with the casing, so as to provide precise centering support for subsequent casing running and cementing operations.

[0047] Example 1 (wellbore adaptation) and Example 2 (casing adaptation) need to be completed simultaneously: First, the centralizer and casing are assembled and adapted through Example 2. Then, the support radius of the centralizer is adjusted to match the wellbore diameter through Example 1. The combination of the two ensures that the casing, centralizer and wellbore are coaxial, and finally the casing is centered and positioned, ensuring that the cement slurry is evenly filled into the outer annular space of the casing during cementing, which meets the requirements of low-carbon mining for cementing quality and wellbore integrity.

[0048] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A casing centralizer with pipe diameter adjustment function, characterized in that, It includes two fixed rings (101) symmetrically distributed on the left and right. Each fixed ring (101) has a plurality of fixed seats (102) evenly spaced along its circumference on its outer surface. Each fixed seat (102) is rotatably connected to a connecting plate (104). An elastic plate (105) is provided between the two connecting plates (104) in the horizontal direction. Both ends of each elastic plate (105) are rotatably connected to the two adjacent connecting plates (104). An adjustment component for adapting to different well diameters is provided between the two fixed rings (101). The adjustment assembly includes an adjustment bolt (108) symmetrically rotated and connected to the left fixed ring (101), and a fixed tube (106) symmetrically distributed with the adjustment bolt (108) in the horizontal direction fixed to the right fixed ring (101). Each adjustment bolt (108) is fixed with a screw (107) on the side close to the fixed tube (106), and each screw (107) is threaded to the adjacent fixed tube (106). Each fixed ring (101) has a plurality of sliding grooves (202) evenly spaced along its circumference. The number of sliding grooves (202) is the same as the number of connecting plates (104). Each sliding groove (202) is provided with a limiting component to ensure the stability of the connecting plate (104). The limiting component includes sliders (203) that are slidably connected in the slide groove (202). Each slider (203) is provided with a connecting rod (201) between it and the adjacent connecting plate (104). The two ends of the connecting rod (201) are rotatably connected to the adjacent connecting plate (104) and the slider (203) respectively. Each left fixing ring (101) has a limiting ring (301) fixedly connected to the side near the adjusting bolt (108). Each adjusting bolt (108) has a locking rod (302) slidably connected to it along its radial direction. Each locking rod (302) is connected to the inner wall of the adjacent adjusting bolt (108) with a spring piece (303). Each locking rod (302) has a locking part (3021) at one end near the limiting ring (301). Each locking part (3021) slides horizontally in the adjacent adjusting bolt (108). Each locking part (3021) is engaged with the adjacent limiting ring (301). Each limiting ring (301) has a uniformly distributed groove on its end face along the circumference, which is used to engage with the locking part (3021).

2. A casing centralizer with pipe diameter adjustment function as described in claim 1, characterized in that, Each fixing ring (101) is provided with a placement hole (103), and each placement hole (103) is machined with an internal thread for installing and fixing the connecting parts.

3. A casing centralizer with pipe diameter adjustment function as described in claim 2, characterized in that, Each placement hole (103) is equipped with a connecting ring (401), and the outer side of the ring is machined with locking threads (402) that match the internal threads of the placement hole (103).

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