Device for enhancing strength of well cementation cement sheath

Abstract

The utility model relates to the field of rock salt mine drilling water solution mining, in particular to a device for enhancing the strength of a well cementation cement sheath, which comprises a connecting pipe, a connecting rod and a connecting rod, a woven spring is arranged in the spring box, and the spring box is fixed at the bottom of the connecting pipe; the spring laying mechanism comprises a first elastic piece, a second elastic piece, an anchor rod and a trigger device, wherein the first elastic piece and the second elastic piece are fixed to the outer side of the connecting pipe. The first elastic piece is connected with the triggering device, the triggering device can be started according to the diameter change of well cementation, the second elastic piece is released after the triggering device is started, and the second elastic piece pushes the anchor rod and fixes the anchor rod to the inner wall of a drilling well; the anchor rod is connected with the braided spring, when the production casing continues to be pushed downwards, the anchor rod pulls the braided spring to surround the production casing, the thickness of the outer ring space of the production casing in an ore-bearing section can be increased by utilizing the device for well cementation, a cement sheath with high overall structural strength can be formed after the springs are automatically arranged and cement is poured in a reaming section, and the production casing is prevented from being damaged. And the service life of the production sleeve is further prolonged.

Description

Technical Field

[0001] This utility model relates to the technical field of water-soluble mining in rock salt mine drilling, and in particular to a device for enhancing the strength of cement sheaths in well cementing. Background Technology

[0002] In my country, rock salt layers in mines are generally characterized by thin layers and multiple interlayers. The first salt layer extracted during drilling and water-based leaching is typically selected at the bottom of the salt-bearing section. Due to gravity differentiation and the general law of dissolution, the brine in the leaching cavity develops very rapidly, especially near the casing. In the middle and later stages of brine production, the casing in the leaching cavity is suspended within the depth range of the salt-bearing section. Under the influence of multiple factors, the production casing is prone to breakage at weak points. One major reason is that during water injection, fluid flows out at the casing opening, and the reaction force generated by the water flow pushes the suspended part of the casing to swing back and forth. Additionally, some rock salt mines have gas-containing surrounding rock strata. During mining, gas accumulates at the top of the leaching cavity. When the casing opening is at the gas-liquid interface, gas enters the casing through the opening. The high-pressure gas expands in volume as the pressure decreases, increasing its flow velocity, which also causes the suspended part of the casing to swing. Due to gravity, the concentration of brine in the melting chamber gradually increases from top to bottom. After the sleeve breaks off, the brine that flows out of the upper part of the melting chamber has a low concentration, or even the brine quality does not meet the production requirements.

[0003] The back-and-forth swinging of the casing not only leads to casing breakage, but also has another major drawback: it damages the cement sheath outside the casing at the top of the cavity, disrupting the tight structure between the casing and the formation. Fresh water at the top of the cavity rises rapidly along the cracks in the broken cement sheath outside the casing, causing the cavity to erode upwards too quickly. This lengthens the suspended portion of the casing, further exacerbating the occurrence of casing breakage and detachment accidents. As a result, horizontal erosion of the cavity becomes difficult to advance, the planar erosion range cannot be expanded, and the recovery rate of controlled resources in the well group cannot be improved.

[0004] The breakage of the production casing and the damage to the cement sheath outside the casing will affect the development and utilization of rock salt resources, resulting in the inability to fully exploit a large amount of rock salt resources controlled by the well group, and also increasing the investment in the construction cost of rock salt mine engineering. Utility Model Content

[0005] (a) Technical problems to be solved

[0006] This invention provides a device for enhancing the strength of cement sheath in well cementing, aiming to solve the problem of production casing breakage caused by insufficient strength of cement sheath in the ore formation, resulting in a lack of protection for the production casing.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, this utility model proposes a spring box for enhancing the strength of the cement sheath in casing cementing, comprising: a connecting pipe disposed at the bottom of the production casing; a spring box containing a braided spring and fixed to the bottom of the connecting pipe; a spring arrangement mechanism including a first spring piece and a second spring piece fixed to the outside of the connecting pipe, an anchor rod, and a triggering device; the first spring piece is connected to the triggering device and can be activated according to the change in the cementing diameter; after the triggering device is activated, the second spring piece is released, and the second spring piece pushes the anchor rod and fixes the anchor rod to the inner wall of the well; the anchor rod is connected to the braided spring, and when the production casing continues to be pushed downward, the anchor rod will pull the braided spring to surround the production casing.

[0009] A further technical solution is that the triggering device includes multiple hinge support rods, a pin pull rod, a pin, and a pin pull rope;

[0010] Multiple hinge support rods are arranged around the connecting pipe, and each hinge support rod has a slot at the top and is hinged to the spring box at the bottom. The anchor rod is inserted into the slot. One end of multiple pin pull rods is connected to multiple hinge support rods in a one-to-one correspondence. The pins are inserted into the pin holes after the pin holes are overlapped. The pins are connected to the first spring piece through the pin pull rope. The first spring piece can pull the pin pull rope to drive the pin out of the pin hole.

[0011] A further technical solution is that the first spring has a spindle-shaped structure, which is sleeved on the outside of the connecting tube and can expand to match the diameter of the well; the inner side of the spindle-shaped structure has multiple threading protrusions, and the pin pull rope passes through the first wire holes on the multiple threading protrusions in sequence and then passes through the second wire hole on the connecting tube to connect to the pin.

[0012] A further technical solution is that the top of the anchor rod has barbs, which are opposite to the connecting pipe and downwards; when the pin is inserted into the pin hole, the top of the hinge support rod approaches the connecting pipe and compresses the second spring, and the hinge support rod drives the top of the anchor rod to approach the connecting pipe; when the pin is disengaged from the pin hole, the second spring returns to its original position, and the hinge support rod drives the barbs at the top of the anchor rod to insert into the inner wall of the well.

[0013] A further technical solution is that the pin tie rod and the hinge support rod are rotatably connected; or the pin tie rod is flexible and connected to the hinge support rod through a threaded adjustment structure, which can pre-adjust the starting angle of the hinge support rod.

[0014] A further technical solution includes a slender clamp, one end of which can extend into the connecting tube and insert the pin into the pin hole.

[0015] A further technical solution is that a conversion joint is provided between the connecting pipe and the production sleeve, and a through hole is opened on the side of the conversion joint for concrete to pass through; the spring box and the connecting pipe are fixedly connected by an annular plate.

[0016] A further technical solution is that the braided spring includes a braided rope and a spring; multiple braided ropes are evenly distributed around the spring and are respectively set for multiple anchor rods; one end of each braided rope is braided with spring wire along the axial direction of the spring, and the other end is connected to the anchor rod.

[0017] A further technical solution is that the diameter of the spring box is larger than the diameter of the production sleeve, and the diameter of the production sleeve is larger than the diameter of the connecting pipe.

[0018] (III) Beneficial Effects

[0019] The cementing device of this invention can increase the thickness of the outer annulus space of the production casing in the ore-bearing section. Automatically deployed springs in the enlarged section further form a high-strength cement sheath. This cement sheath structure enhances the bond strength between the production casing and the formation, making it less likely for fresh water to seep through the outer annulus. The addition of springs as a framework within the cement sheath further strengthens it, preventing damage to the suspended production casing during oscillation. Furthermore, even when the production casing is suspended, the cement sheath firmly encases it, significantly increasing the weight of the suspended portion. With the same flow rate and velocity of medium injected into the production casing, the oscillation amplitude is greatly reduced, which is more conducive to maintaining casing stability, reducing the rate of leaching, and maintaining high-concentration brine production, greatly benefiting the well group's recovery rate. Secondly, the cement ring structure also reduces the probability of the outer annulus of the production casing at the top plate of the molten cavity being crushed and damaged, extends the life of the suspended part of the production casing, and reduces the speed of molten cavity development, which is very beneficial to brine production. Attached Figure Description

[0020] Figure 1 A schematic diagram of the overall structure of a device for enhancing the strength of cement sheaths in well cementing.

[0021] Figure 2 for Figure 1 Schematic diagram of the cross-section at point AA;

[0022] Figure 3 for Figure 1 Schematic diagram of the cross-section at point BB;

[0023] Figure 4 for Figure 1 Schematic diagram of the cross-section at point C;

[0024] Figure 5 for Figure 1 Schematic diagram of the cross-section at point D;

[0025] Figure 6 This is a schematic diagram of the unfolded braided spring.

[0026] [Explanation of Labels in the Attached Image]

[0027] 1: Production sleeve; 2: Connecting pipe; 3: Spring box; 4: Braided spring; 41: Braided rope; 42: Spring; 5: Spring placement mechanism; 51: First spring piece; 511: Threading protrusion; 52: Second spring piece; 53: Anchor rod; 531: Barb; 54: Triggering device; 541: Hinge support rod; 542: Pin pull rod; 543: Pin; 544: Pin pull rope; 6: Converter joint; 61: Through hole; 7: Annular plate; 8: First wire hole; 9: Second wire hole. Detailed Implementation

[0028] To better explain and facilitate understanding of this utility model, the present utility model will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] Taking a rock salt mine as an example, the salt layer is buried at a depth of 2400m, with a salt-bearing section thickness of 50m. The surrounding rock at the top of the salt layer is dolomite and limestone. The diameter of the second borehole in the brine well is 215.9mm, and the production casing specifications are 177.8×9.19mm. Five years after the newly added well group in the salt mine was put into production, the brine concentration suddenly decreased and could no longer meet the brine concentration requirements of the salt production system. The newly constructed brine wells need to address the problem of short effective service life. The construction of new brine wells requires enhancing the cementing quality of the ore-bearing section to delay the time when the production casing in the solution cavity is suspended and breaks.

[0030] This embodiment provides a device for enhancing the strength of cement sheaths in well cementing, such as... Figures 1-3 As shown, it includes

[0031] Connecting pipe 2 is located at the bottom of production sleeve 1. Specifically, connecting pipe 2 is connected to production sleeve 1 through a drillable connector. The two ends of the drillable connector are connected to production sleeve 1 and connecting pipe 2 respectively through threads. This connection method facilitates on-site installation.

[0032] The spring box 3 contains a braided spring 4 and is fixed to the bottom of the connecting tube 2. Specifically, the spring box 3 and the connecting tube 2 can be connected by welding to ensure a reliable connection. The braided spring 4 refers to the spring wires being sequentially bound along the axial direction of the spring 42 by braided rope 41.

[0033] The spring-laying mechanism 5 includes a first spring plate 51 and a second spring plate 52 fixed to the outside of the connecting pipe 2, an anchor rod 53, and a triggering device 54. Specifically, the first spring plate 51 is connected to the triggering device 54. The first spring plate 51 can activate the triggering device 54 according to the change in the diameter of the cementing well. After the triggering device 54 is activated, it releases the second spring plate 52, which pushes the anchor rod 53 and fixes it to the inner wall of the cementing well. The anchor rod 53 is connected to a braided spring 4. When the production casing 1 continues to descend, the anchor rod 53 will pull the braided spring 4 to surround the production casing 1. The first spring plate 51 and the second spring plate 52 are connected to the outside of the connecting pipe 2 by welding or snap-fitting.

[0034] Using the aforementioned device for cementing increases the thickness of the outer annulus space of the production casing 1 in the ore-bearing section. By arranging elastic supports in the enlarged section, a high-strength cement sheath structure is formed. This cement sheath structure makes it less likely for fresh water to seep through the outer annulus of the production casing 1. The addition of springs 42 as a skeleton within the cement sheath enhances its strength, preventing damage to the suspended production casing 1 during oscillation. Even when the production casing 1 is suspended, the cement sheath firmly encases it, significantly increasing the weight of the suspended portion. When the same flow rate and velocity of medium are injected into the production casing 1, the oscillation amplitude of the production casing 1 is very small, which is more conducive to maintaining the stability of the production casing 1. This reduces the rate of dissolution development while maintaining a high concentration of brine, greatly benefiting the improvement of well recovery rate.

[0035] In this embodiment, the triggering device 54 includes four hinge support rods 541, four pin pull rods 542, pins 543, and pin pull ropes 544. The four hinge support rods 541 are arranged around the connecting pipe 2, and each hinge support rod 541 has a slot at its top and is hinged to the spring box 3 at its bottom. An anchor rod 53 is inserted into the slot. Specifically, the four hinge support rods 541 are rotatably connected to the top of the spring box 3, allowing the hinge support rods 541 to have a certain range of motion while maintaining the ability to reset. The slots on the hinge support rods 541 are square, and the bottom of the corresponding anchor rod 53 is a matching square. This arrangement will prevent the anchor rod 53 from rotating during the swinging process.

[0036] One end of each of the four pin pull rods 542 is connected to one of the four hinge support rods 541. The pins 543 are inserted into the pin holes at the other end after they are aligned. The pins 543 are connected to the first spring piece 51 through the pin pull rope 544. The first spring piece 51 can pull the pin pull rope 544 to drive the pins 543 out of the pin holes.

[0037] Specifically, the first spring clip 51 has a spindle-shaped structure, which is fitted onto the outside of the connecting pipe 2 and can expand to match the diameter of the cementing; the inner side of the spindle-shaped structure has multiple threading protrusions 511, which are located at the position of the largest diameter of the spindle-shaped structure to better activate the triggering device 54. Combined with... Figure 4 and Figure 5 As shown, the pin pull rope 544 passes through the first wire hole 8 on multiple wire protrusions 511 in sequence and then connects to the pin 543 through the second wire hole 9 on the connecting tube 2. Preferably, a ceramic ring is provided inside the first wire hole 8, which can effectively reduce the friction force of the pin pull rope 544.

[0038] Specifically, the top of the anchor rod 53 has barbs 531, which face away from the connecting pipe 2 and towards the inner wall of the well, and have a downward angle with the connecting pipe 2 to facilitate better insertion and rivet fixation to the inner wall of the well. When the pin 543 is inserted into the pin 543 hole, the top of the hinge support rod 541 approaches the connecting pipe 2 and compresses the second spring 52, causing the hinge support rod 541 to move the top of the anchor rod 53 towards the connecting pipe 2; when the pin 543 disengages from the pin 543 hole, the second spring 52 returns to its original position, and the hinge support rod 541 causes the barbs 531 at the top of the anchor rod 53 to insert into the inner wall of the well.

[0039] In this embodiment, the pin tie rod 542 and the hinge support rod 541 are rotatably connected. This is to ensure that the pin tie rod 542 does not interfere with the connecting pipe 2 during the rotation of the hinge support rod 541. Alternatively, the pin tie rod 542 can be given more room to move by increasing the through-hole size on the connecting pipe 2, or a more flexible pin tie rod 542 can be used. Preferably, the pin tie rod 542 and the hinge support rod 541 are connected by a threaded adjustment structure. This design allows for pre-adjustment of the initial angle of the hinge support rod 541.

[0040] In this embodiment, a slender clamp is also included. One end of the slender clamp can extend into the connecting tube 2 and insert the pin 543 into the pin 543 hole. The head of the slender clamp can be magnetically attached, which allows for quick insertion and placement of the pin 543.

[0041] In this embodiment, a drillable conversion joint 6 is provided between the connecting pipe 2 and the production sleeve 1. The conversion joint 6 has a through hole 61 on its side. The through hole 61 is elongated and used to pass through concrete. The spring box 3 and the connecting pipe 2 are fixedly connected by an annular plate 7.

[0042] In this embodiment, combined with Figure 6As shown, the braided spring 4 includes a braided rope 41 and a spring 42; specifically, the braided rope 41 is made of flexible fine steel wire, and there are four of them. The four braided ropes 41 are evenly distributed around the spring 42 and are respectively set for the four anchor rods 53; one end of each braided rope 41 is braided along the axial direction of the spring 42, and the other end is connected to the anchor rod 53.

[0043] It should be noted in this embodiment that the diameter of the spring box 3 is larger than the diameter of the production sleeve 1, and the diameter of the production sleeve 1 is larger than the diameter of the connecting pipe 2.

[0044] The specific steps for cementing using the aforementioned device to enhance the strength of cement sheaths are as follows:

[0045] First, 3mm diameter elastic steel wire made of 316 stainless steel is bent into spring 42. The mean diameter of spring 42 is 255mm and the helix angle is 5.6°. The depth range for reinforcing the cement sheath outside the brine well production casing 1 is the ore-bearing section and 10m above the top of the ore layer, totaling 60m. 3mm elastic steel wire is used as the spring wire, and it is spread out in the reinforcement section at 30mm intervals. The number of turns of spring 42 is 2000. Four braided ropes 41 are used to braid the elastic steel wire one by one at a symmetrical angle to form spring 42, and an 8m long, 177.8mm spring box 3 is made. It should be noted that the mean diameter of spring 42 is determined by the interval between the borehole diameter and the production casing 1, and is generally 20mm smaller than the borehole diameter. Spring 42 is spirally compressed and placed into spring box 3 to reduce the mean diameter of spring 42. After the device is lowered to the reaming depth, the braided ropes 41 can be pulled out of the casing from spring 42, and spring 42 automatically returns to its original mean diameter and is fitted on the outside of production casing 1.

[0046] Next, the connecting pipe 2 and the spring box 3 are welded and fixed using a circular steel plate. The woven elastic steel wire braided spring 4 is spirally pressed into the spring box 3. Four barbed anchor rods 53 are inserted into the slots on the hinge support rod 541. The braided rope 41 at the end of the woven spring 4 is tied to the barbed anchor rod 53. The second spring piece 52 is tied with the rope. The barbed anchor rod 53 is brought closer to the connecting rod. One end of the pin pull rope 544 is used to string the four first spring pieces 51 together, and the other end is inserted into the connecting rod through the first wire hole 8 on the connecting rod. A thin clamp is used to pull the connecting rod... Pull out the pin pull rope 544 from the top and tie the pin 543. Adjust the four pin pull bars 542 so that the pin 543 holes at the ends of the four pin pull bars 542 overlap. Use a slender clamp to send the pin 543 into the pin 543 hole. Immediately untie the binding rope on the second spring piece 52. At the same time, tie the first spring piece 51 with a strip so that its outer diameter is smaller than the outer diameter of the production casing 1. Adjust the length of the pin pull rope 544. The specific length should be able to pull out the pin 543 when the device passes through the drilling and enlargement section of the well.

[0047] The cement sheath outside the production casing 1 of the brine well needs reinforcement to a depth ranging from the ore-bearing section to 10m above the top of the ore layer, totaling 60m in length. Based on the length of the spring placement mechanism 5 used for cementing, a pocket of at least 10m needs to be installed at the bottom of the borehole. The second drilling operation of the brine well uses a 215.9mm drill bit to drill to the depth below the production casing 1 or drills vertically downwards to a depth of 10m, ensuring the required pocket length for open-hole logging and the spring placement mechanism 5 used for cementing. Then, the drill string, equipped with a YK216-280 hydraulic reamer, performs reaming operations on the ore-bearing section, including the 10m depth above the top of the ore layer. Multiple reaming operations can be performed to ensure reaming quality. It should be noted that reaming is to increase the gap between the casing and the formation, allowing sufficient space for the spring box 3 to evenly release the springs 42 and maintain their uniform distribution. It also increases the thickness of the cement sheath, which is beneficial for enhancing the bond strength between the production casing 1 and the formation. Increasing the weight of the suspended production casing 1 section can improve its stability and reduce swaying caused by water injection backflush. It also reduces the integrity of the cement sheath outside the steel casing at the top of the cavitation cavity, slowing down the cementing rate. Furthermore, a hydraulic centralizer is installed for every three production casings 1 in the reamed section to ensure the production casing 1 is centered in the borehole. Spring 42 and the cement sheath are evenly distributed around the casing, increasing the structural strength of the cement sheath and the cementing quality. After reaming, the annular gap between the production casing 1 and the formation is larger, and conventional centralizers are no longer sufficient to keep the production casing 1 centered; therefore, hydraulic centralizers are used.

[0048] After the reaming operation is completed, the borehole is cleaned and the production casing 1 equipped with the cementing spring laying mechanism 5 is prepared for lowering. The cementing elastic wire automatic laying device is connected to the production casing 1 via a drillable adapter 6 and can then be lowered into the well. When the first spring clip 51 just enters the surface casing or intermediate casing, the strap binding rope on the first spring clip 51 should be loosened, and then the production casing 1 is added one by one. At this time, the first spring clip 51 is close to the borehole wall. After being lowered into the reaming section, the four first spring clips 51 unfold outwards, and the pin pull rope 544 is pulled to pull the pin 543 out of the pin pull strip 542 hole. Under the action of the second force spring clip, the four hinge support rods 541 pull the four barbed rods 53. Anchor bolt 53 is pressed against the well wall. After the barbs 531 on the four barbed anchor bolts 531 come into contact with the well wall, they will penetrate into the formation and eventually be riveted to the well wall. The barbed anchor bolts 531 detach from the hinge support rod 541 and pull the braided rope 41, gradually pulling the braided spring 4 out of the spring box 3 until the bottom of the production casing 1 is lowered to the designed position and then stops. Since the connecting pipe 2 is hollow and the side of the conversion joint 6 has a long strip hole structure, the device does not affect the normal injection of cement slurry for cementing. The drillable conversion joint 6 is drilled off when cleaning the cement plug. Preferably, the production casing 1 is slowly lowered 2m before entering the reaming section. To ensure that the first spring 51 is fully deployed at the moment of entering the reaming section, the pin pulling rope 544 is pulled to pull the pin 543 out of the pin 543 hole.

[0049] Applying the above cementing technology to brine well construction can ensure that the controlled resource recovery rate of the well group reaches over 70%, and the service life of the brine well can generally reach over 15 years. This is particularly beneficial for the full exploitation of rock salt resources, especially for thick brine-producing salt layers. Based on a typical well group casing spacing of 200m and a melting radius of 50m, the controlled NaCl resource reserves of the well group are 2.5 million tons, with a designed recoverable NaCl amount of 1.75 million tons. The well group is designed with a 100m... 3 With a brine return rate of / h, a NaCl brine concentration of 300g / l, and an annual production time of 8000h, the well group can extract 240,000 tons of brine equivalent to salt annually. The well group can reach the level of fully extracting rock salt resources after 8 years of normal production and operation, which is completely controlled within the service life range of the well group.

[0050] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this embodiment are only used to explain the relative positional relationship and movement of each component in a specific posture (as shown in the attached figure). If the specific posture changes, the directional indicator will also change accordingly.

[0051] Furthermore, in this embodiment, the use of terms such as "first" and "second" is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of those features. In the description of this embodiment, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0052] In this embodiment, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this embodiment according to the specific circumstances.

[0053] It should be understood that the above description of the specific embodiments of this utility model is only for illustrating the technical route and features of this utility model, and its purpose is to enable those skilled in the art to understand the content of this utility model and implement it accordingly. However, this utility model is not limited to the specific embodiments described above. All changes or modifications made within the scope of the claims of this utility model should be covered by the protection scope of this utility model.

Claims

1. A device for enhancing the strength of cement sheaths in well cementing, characterized in that, include: Connecting pipe (2) is located at the bottom of production sleeve (1); A spring box (3) is provided with a braided spring (4) and is fixed to the bottom of the connecting tube (2); The spring arrangement mechanism (5) includes a first spring piece (51) and a second spring piece (52) fixed to the outside of the connecting pipe (2), an anchor rod (53), and a triggering device (54); The first spring (51) is connected to the triggering device (54) and can activate the triggering device (54) according to the change in the diameter of the cementing. After the triggering device (54) is activated, it releases the second spring (52), which pushes the anchor rod (53) and fixes the anchor rod (53) to the inner wall of the well. The anchor rod (53) is connected to the braided spring (4). When the production casing (1) continues to be pushed down, the anchor rod (53) will pull the braided spring (4) to surround the production casing (1).

2. The device for enhancing the strength of cement sheaths as described in claim 1, characterized in that, The triggering device (54) includes multiple hinge support rods (541), pin pull rods (542), pins (543), and pin pull ropes (544); Multiple hinge support rods (541) are arranged around the connecting pipe (2), and each hinge support rod (541) has a slot at the top and is hinged to the spring box (3) at the bottom, and the anchor rod (53) is inserted into the slot. One end of each of the multiple pin pull rods (542) is connected to one of the multiple hinge support rods (541), and the pin (543) holes at the other end are aligned and inserted into the pin (543). The pin (543) is connected to the first spring piece (51) through the pin pull rope (544). The first spring piece (51) can pull the pin pull rope (544) to drive the pin (543) out of the pin (543) hole.

3. The device for enhancing the strength of cement sheaths as described in claim 2, characterized in that, The first spring (51) has a spindle-shaped structure, is sleeved on the outside of the connecting pipe (2), and can expand to match the diameter of the well. The inner side of the spindle-shaped structure has multiple threading protrusions (511). The pin pull rope (544) passes through the first thread hole (8) on the multiple threading protrusions (511) in sequence and then passes through the second thread hole (9) on the connecting tube (2) to connect to the pin (543).

4. The device for enhancing the strength of cement sheaths as described in claim 2, characterized in that, The top of the anchor rod (53) has barbs (531) that are away from the connecting pipe (2) and are oriented downwards; When the pin (543) is inserted into the pin (543) hole, the top end of the hinge support rod (541) approaches the connecting pipe (2) and compresses the second spring piece (52). The hinge support rod (541) then drives the top end of the anchor rod (53) to approach the connecting pipe (2). When the pin (543) disengages from the pin (543) hole, the second spring (52) resets, and the hinge support rod (541) drives the barb (531) at the top of the anchor rod (53) to insert into the inner wall of the well.

5. The device for enhancing the strength of cement sheaths as described in claim 2, characterized in that, The pin tie rod (542) and the hinge support rod (541) are rotatably connected; or the pin tie rod (542) is flexible and is connected to the hinge support rod (541) through a threaded adjustment structure, which can pre-adjust the starting angle of the hinge support rod (541).

6. The device for enhancing the strength of cement sheaths as described in claim 2, characterized in that, It also includes a slender clamp, one end of which can extend into the connecting tube (2) and insert the pin (543) into the pin (543) hole.

7. The device for enhancing the strength of cement sheaths as described in claim 1, characterized in that, A conversion joint (6) is provided between the connecting pipe (2) and the production sleeve (1). A through hole (61) is provided on the side of the conversion joint (6) for passing through concrete. The spring box (3) and the connecting pipe (2) are fixedly connected by an annular plate (7).

8. The device for enhancing the strength of cement sheaths as described in claim 1, characterized in that, The braided spring (4) includes a braided rope (41) and a spring (42); Multiple braided ropes (41) are evenly distributed around the spring (42) and are respectively set for multiple anchor rods (53); One end of each of the braided ropes (41) is braided along the axial direction of the spring (42) with spring wire, and the other end is connected to the anchor rod (53).

9. The apparatus for enhancing the strength of cement sheaths as described in claim 1, characterized in that, The diameter of the spring box (3) is greater than the diameter of the production sleeve (1), and the diameter of the production sleeve (1) is greater than the diameter of the connecting pipe (2).

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