A seat-mounted self-locking floating hoop and matching rubber plug device and use method thereof

Abstract

The present invention provides a seat-hanging self-locking floating hoop and a matching rubber plug device and a method of use. The device includes a seat-hanging self-locking floating hoop and a seat-hanging self-locking rubber plug. The seat-hanging self-locking rubber plug is connected to the seat-hanging self-locking floating hoop through a seat-hanging ring. The seat-hanging self-locking rubber plug includes a rubber plug body, a spring limiting shaft, a rubber plug spring, a fixing ring, a seat-hanging head, a mud scraping ring and a pressure ring; the outer lower end of the seat-hanging head is sleeved with a pressure ring and a mud scraping ring in sequence from bottom to top; the fixing ring is sleeved on the upper end of the seat-hanging head, the lower part of the spring limiting shaft is located in the fixing ring, and the rubber plug spring is arranged between the spring limiting shaft and the fixing ring; the fixing ring is connected to the rubber plug body. In the present invention, the valve hole in the valve seat adopts a straight hole structure, which effectively reduces the accumulation of mud and sand and improves the reliability of the device. The provision of the mud scraping ring in the present invention can effectively scrape off the residual mud and sand on the sealing surface, thereby improving the sealing and seat hanging reliability.

Description

Technical Field

[0001] The invention relates to the technical field of cementing construction for petroleum well completion, and in particular to a seat-hanging self-locking floating collar and a matching rubber plug device and a use method thereof. Background Art

[0002] The existing self-locking anti-backward floating adopts a limit ring type reduced diameter self-locking or barbed ring type meshing self-locking structure. When used on site, there are situations where the rubber plug is damaged by wear or the mud and sand cannot mesh, and it is impossible to ensure that the rubber plug and the matching anti-backward floating hoop are completely locked after collision and pressure. In the case of failure of the single flow valve of the floating hoop and the floating shoe, the reverse flow cannot be cut off, and cement plugs are easily left. The positive pressure bearing capacity after the rubber plug is collided and pressed is also difficult to meet the requirements of wellbore sealing for later completion and fracturing.

[0003] The invention with invention patent number CN202010764385.4 discloses a floating hoop and rubber plug interlocking device and application method, specifically, a shrink pin method is used to achieve interlocking of the rubber plug and the floating hoop.

[0004] The invention with patent number CN201911095001.8 discloses a self-locking impact-pressure floating collar device and a cementing rubber plug anti-floating method, which specifically adopts a reverse barbed petal structure to achieve interlocking of the rubber plug and the floating collar.

[0005] The [Utility Model] with application number CN201921794218.3 discloses a double-sealed anti-backward floating rubber plug and a self-locking anti-backward floating hoop, which specifically adopts a barbed ring-type meshing self-locking structure to achieve interlocking of the rubber plug and the floating hoop.

[0006] According to the documents retrieved above, each self-locking method is not easy to operate and is not safe. Summary of the invention

[0007] In order to overcome the existing problems of poor operation, reliability and insecurity, the present invention provides a seat-hanging self-locking floating hoop and a matching rubber plug device and a method of using the same. In the present invention, the valve hole in the valve seat adopts a straight hole structure, which effectively reduces the accumulation of mud and sand and improves the reliability of the device. The present invention has a self-locking function. During the collision and pressure process, the rubber plug body moves downward, and the seat hanging head body of the seat hanging head is compressed by the spring limit shaft, so that the seat hanging ring expands and realizes mechanical seat hanging self-locking with the inner wall of the valve seat. The setting of the scraper ring in the present invention can effectively scrape off the residual mud and sand on the sealing surface, thereby improving the sealing and seat hanging reliability.

[0008] The technical solution adopted by the present invention is:

[0009] A seat-hanging self-locking floating hoop and a matching rubber plug device, comprising a seat-hanging self-locking floating hoop and a seat-hanging self-locking rubber plug. The seat-hanging self-locking rubber plug is connected in the seat-hanging self-locking floating hoop through a seat-hanging ring.

[0010] The seat-hanging self-locking rubber plug comprises a rubber plug body, a spring limiting shaft, a rubber plug spring, a fixing ring, a seat-hanging head, a mud scraping ring and a pressure ring; the pressure ring and the mud scraping ring are sleeved on the outer side of the lower end of the seat-hanging head in sequence from bottom to top; the fixing ring is sleeved on the upper end of the seat-hanging head, the lower part of the spring limiting shaft is located in the fixing ring, and the rubber plug spring is arranged between the spring limiting shaft and the fixing ring; the fixing ring is connected to the rubber plug body.

[0011] The seat hanging head includes a seat hanging head body and a circular ring protrusion, the circular ring protrusion is located at the center of the upper end of the seat hanging head body, and the maximum outer diameter of the circular ring protrusion is smaller than the outer diameter of the upper end of the seat hanging head body; the lower end of the circular ring protrusion and the upper end of the seat hanging head body form an annulus; the seat hanging head body is a cylindrical structure with a larger bottom and a smaller top; two stepped external threads are opened at the lower end of the seat hanging head body; the two external threads are respectively connected to the corresponding pressure ring and the scraper ring; the seat hanging ring is sleeved on the outer wall of the upper end of the seat hanging head body.

[0012] A plurality of sliding grooves are provided on the side wall of the circular ring protrusion.

[0013] The slide groove on the circular ring protrusion is fixed by the corresponding pin hole on the fixed shaft and the fixed ring.

[0014] The spring limiting shaft comprises a limiting shaft body and a limiting plate. The limiting plate is located at the upper end of the limiting shaft body, and the outer diameter of the limiting plate is greater than the outer diameter of the lower end shaft of the spring limiting shaft.

[0015] A circular hole is opened at the lower end of the plug body, a fixing ring is arranged in the circular hole, the outer diameter of the limiting plate of the spring limiting shaft arranged in the fixing ring matches the size of the circular hole, and the limiting plate of the spring limiting shaft is in contact with and connected to the bottom surface of the circular hole.

[0016] The seat hanging head is provided with a sealing groove, and a first sealing ring is arranged in the sealing groove.

[0017] The seat-hung self-locking floating hoop comprises a floating hoop shell, a righting ring, a valve seat, a rubber valve, a floating hoop spring and a spring cover; the floating hoop spring is arranged on the rubber valve, the lower end of the rubber valve is connected to the spring cover, the upper end of the rubber valve is connected to the valve seat, the valve seat is arranged in the righting ring, and the righting ring is located in the floating hoop shell; the valve seat and the floating hoop shell are sealed and connected by a second sealing ring.

[0018] A method for using a seat-mounted self-locking floating collar and a matching rubber plug device, the specific steps are:

[0019] Step 1: Install the self-locking floating collar between the required casing strings;

[0020] Step 2: insert the casing into the well and perform cementing operations;

[0021] Step 3: Before cementing and displacement, install the seat-hanging self-locking rubber plug into the casing string to displace cement slurry;

[0022] Step 4: When the seat-hanging self-locking rubber plug enters the seat-hanging self-locking floating hoop, the scraper ring circulates the mud and debris in the inner hole of the valve seat to scrape. Finally, when the pressure ring reaches the bottom of the inner hole of the valve seat, the seat head compresses the spring backward and contracts. The rubber plug body pushes the seat ring to expand along the conical surface of the seat head to realize seat self-locking. At the same time, the first sealing ring realizes channel sealing to achieve seat sealing.

[0023] The beneficial effects of the present invention are:

[0024] The present invention provides a scraper ring, which can effectively scrape off residual mud and sand on the sealing surface. The scraper ring is a truncated cone-shaped ring that is larger at the top and smaller at the bottom. The maximum outer diameter of the scraper ring is larger than the maximum outer diameter of the lower end of the seat hanging head. Such a scraper ring improves the reliability of sealing and seat hanging.

[0025] The invention has a self-locking function. During the collision and pressing process of the displacement fluid, the rubber plug body moves downward, and the seat hanging head body of the seat hanging head is compressed by the spring limit shaft, so that the seat hanging ring expands and realizes mechanical seat hanging self-locking with the inner wall of the valve seat.

[0026] In the present invention, the countersunk hole at the upper port of the valve seat increases the sealing gradient of the seat-mounted self-locking rubber plug to the valve hole on the valve seat, and the side wall of the countersunk hole is conical, which increases the sealing surface of the seat-mounted self-locking rubber plug to the countersunk hole, further improving the sealing between the seat-mounted self-locking rubber plug and the valve seat.

[0027] In the present invention, the valve hole in the valve seat adopts a straight hole structure, which effectively reduces the accumulation of mud and sand and improves the reliability of the device.

[0028] The following is a further description with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the structure of the seat-hung self-locking rubber plug in the present invention.

[0030] Figure 2 It is a schematic diagram of the structure of the seat-hung self-locking floating hoop in the present invention.

[0031] Figure 3 It is a front schematic diagram of the seat hanging of the present invention.

[0032] Figure 4 It is a schematic diagram of the seat hanging of the present invention.

[0033] FIG. 5 ( a ) is a schematic diagram of the three-dimensional structure of the seat hanging head of the present invention.

[0034] FIG. 5( b ) is a front view of the seat hanging head of the present invention.

[0035] FIG5( c ) is a cross-sectional view of the seat hanging head of the present invention.

[0036] Figure 6 It is a schematic diagram of the structure of the rubber plug body.

[0037] Figure 7 It is a schematic diagram of the spring limit shaft structure.

[0038] In the figure, the reference numerals are: 1, rubber plug body; 2, spring limit shaft; 3, rubber plug spring; 4, fixed ring; 5, fixed shaft; 6, seat hanging ring; 7, seat hanging head; 701, seat hanging head body; 702, circular ring protrusion; 703, slide groove; 704, sealing groove; 8, mud scraper ring; 9, small sealing ring; 10, pressure ring; 11, floating hoop shell; 12, righting ring; 13, valve seat; 14, rubber hanging valve; 15, large sealing ring; 16, floating hoop spring; 17, spring cover. DETAILED DESCRIPTION

[0039] Embodiment 1:

[0040] In order to overcome the problems of poor reliability and insecurity of the existing operation, the present invention provides Figure 1-7 The present invention shows a seat-hanging self-locking floating hoop and a matching rubber plug device and a method of using the same. In the present invention, the valve hole in the valve seat adopts a straight hole structure, which effectively reduces the accumulation of mud and sand and improves the reliability of the device. The present invention has a self-locking function. During the collision and pressure process, the rubber plug body moves downward, and the seat hanging head body of the seat hanging head is compressed by the spring limit shaft, so that the seat hanging ring expands and realizes mechanical seat hanging self-locking with the inner wall of the valve seat. The setting of the scraper ring in the present invention can effectively scrape off the residual mud and sand on the sealing surface, thereby improving the sealing and seat hanging reliability.

[0041] A seat-hanging self-locking floating hoop and a matching rubber plug device, comprising a seat-hanging self-locking floating hoop and a seat-hanging self-locking rubber plug, wherein the seat-hanging self-locking rubber plug is connected in the seat-hanging self-locking floating hoop through a seat-hanging ring 6.

[0042] When the present invention is in use, during the process of displacement fluid impacting and pressing the seat-hanging self-locking rubber plug, the seat-hanging self-locking rubber plug downwardly enters into the seat-hanging self-locking floating hoop, compresses the seat-hanging self-locking rubber plug so that the seat-hanging ring 6 expands, realizes mechanical seat-hanging self-locking with the inner wall of the seat-hanging self-locking floating hoop, ensures that the seat-hanging self-locking rubber plug will not float, and improves reliability.

[0043] Embodiment 2:

[0044] Based on Example 1, in this embodiment, preferably, Figure 1As shown, the seat-hanging self-locking rubber plug includes a rubber plug body 1, a spring limiting shaft 2, a rubber plug spring 3, a fixing ring 4, a seat-hanging head 7, a mud scraping ring 8 and a pressure ring 10; the pressure ring 10 and the mud scraping ring 8 are sequentially sleeved on the outer side of the lower end of the seat-hanging head 7 from bottom to top; the fixing ring 4 is sleeved on the upper end of the seat-hanging head 7, the lower part of the spring limiting shaft 2 is located in the fixing ring 4, and the rubber plug spring 3 is arranged between the spring limiting shaft 2 and the fixing ring 4; the fixing ring 4 is connected to the rubber plug body 1.

[0045] The present invention provides a scraper ring 8, which can effectively scrape away residual mud and sand on the sealing surface, thereby improving the reliability of sealing and seat hanging. In the present invention, the scraper ring 8 is a truncated cone-shaped ring with a larger upper portion and a smaller lower portion. The maximum outer diameter of the scraper ring 8 is greater than the maximum outer diameter of the lower end of the seat hanging head 7.

[0046] Preferably, the side wall of the annular protrusion 702 is provided with a plurality of sliding grooves 703. 704

[0047] Preferably, the slide groove 703 on the annular protrusion 702 is fixed by a corresponding pin hole on the fixing shaft 5 and the fixing ring 4 .

[0048] Preferably, the spring limiting shaft 2 comprises a limiting shaft body and a limiting plate, wherein the limiting plate is located at the upper end of the limiting shaft body, and the outer diameter of the limiting plate is greater than the outer diameter of the lower end shaft of the spring limiting shaft 2 .

[0049] Preferably, a circular hole is opened at the lower end of the plug body 1, a fixing ring 4 is arranged in the circular hole, the outer diameter of the limiting plate of the spring limiting shaft 2 arranged in the fixing ring 4 matches the size of the circular hole, and the limiting plate of the spring limiting shaft 2 is in contact and connected with the bottom surface of the circular hole.

[0050] Preferably, a sealing groove 704 is provided on the seat hanging head 7, and a first sealing ring 9 is installed in the sealing groove 704.

[0051] In the present invention, there are two sealing grooves, and first sealing rings 9 are arranged in both sealing grooves.

[0052] Preferably, as shown in Figures 5(a), 5(b) and 5(c), the seat head 7 includes a seat head body 701 and an annular protrusion 702, the annular protrusion 702 is located at the center of the upper end of the seat head body 701, and the maximum outer diameter of the annular protrusion 702 is smaller than the outer diameter of the upper end of the seat head body 701; the lower end of the annular protrusion 702 forms an annulus with the upper end of the seat head body 701; the seat head body 701 is a cylindrical structure with a larger lower portion and a smaller upper portion; the lower end of the seat head body 701 is provided with two stepped external threads; the two external threads are respectively connected to the corresponding pressure ring 10 and the scraper ring 8; the seat ring 6 is sleeved on the outer wall of the upper end of the seat head body 701.

[0053] In the present invention, the inner wall of the seat hanging ring 6 is larger at the bottom and smaller at the top, which is opposite to the seat hanging head body 701 . The seat hanging ring 6 is closely attached to the seat hanging head body 701 and sleeved on the upper end of the seat hanging head body 701 .

[0054] In the present invention, the assembly process of the seat-hung self-locking rubber plug is as follows:

[0055] First, install the scraper ring 8 into the corresponding shaft of the seat hanging head 7, then tighten and fix the pressure ring 10 with the corresponding thread of the seat hanging head 7, then install the first sealing ring 9 into the corresponding sealing groove of the seat hanging head 7, then put the seat hanging ring 6 on the top of the seat hanging head 7, then put the fixing ring 4 into the upper end of the seat hanging head 7, ensure that the angle of the pin hole on the fixing ring 4 corresponds to the sliding groove of the seat hanging head 7, then install the 4 fixing shafts 5, then put the rubber plug spring 3 into the spring limiting shaft 2, then put the spring limiting shaft 2 into the hole of the fixing ring 4, and finally tighten the fixing ring 4 with the rubber plug body 1, so far the seat hanging self-locking rubber plug in the invention device is assembled. In the present invention, the seat hanging self-locking rubber plug shrinks during the collision and pressure process, forcing the seat hanging ring 6 to expand and open the valve seat 13 with the floating hoop to realize mechanical seat hanging self-locking.

[0056] In the present invention, Figure 7 As shown, the plug body 1 is in the shape of a cylindrical cone as a whole, and a plurality of triangular teeth are symmetrically arranged on both sides of the plug body 1. The end face diameter of the lower end face of the plug body 1 is smaller than the cross-sectional diameter of the middle part of the plug body 1. The upper end of the plug body 1 is in the shape of a fishtail, and a countersunk hole is opened at the upper end of the plug body 1; a circular hole is opened in the middle of the lower end of the plug body 1, and the inner diameter of the circular hole matches the outer diameter of the fixing ring 4.

[0057] In the present invention, Figure 6 As shown, the length of the limiting shaft body of the spring limiting shaft 2 is longer than the length of the fixing ring 4. During the collision and pressing process, the rubber plug body 1 moves downward, and the seat hanging head body 701 of the seat hanging head 7 is compressed by the spring limiting shaft 2, so that the seat hanging ring 6 expands and realizes mechanical seat self-locking with the inner wall of the valve seat 13. In the present invention, the upper end of the rubber plug spring 3 is clamped on the lower surface of the limiting plate of the spring limiting shaft 2. The size of the limiting plate of the spring limiting shaft 2 matches the circular hole at the lower end of the rubber plug body 1. The size of the circular hole is determined according to the cooperation of the spring limiting shaft 2 and the circular ring protrusion 702. Ensure that the fixing ring 4 moves up and down along the limiting shaft of the spring limiting shaft 2.

[0058] Preferably, Figure 2 As shown, the seat-hung self-locking floating hoop includes a floating hoop shell 11, a righting ring 12, a valve seat 13, a rubber valve 14, a floating hoop spring 16 and a spring cover 17; the floating hoop spring 16 is arranged on the rubber valve 14, the lower end of the rubber valve 14 is connected to the spring cover 17, the upper end of the rubber valve 14 is connected to the valve seat 13, the valve seat 13 is arranged in the righting ring 12, and the righting ring 12 is located in the floating hoop shell 11; the valve seat 13 and the floating hoop shell 11 are sealed and connected via a second sealing ring 15.

[0059] In the present invention, the assembly process of the seat-hanging self-locking floating collar is as follows:

[0060] First, insert the floating hoop spring 16 into the rubber valve 14, then put the rubber valve 14 with the spring into the corresponding hole of the valve seat 13, then install the spring cover 17 into the valve seat 13, then install the large sealing ring 15 in the corresponding sealing groove of the valve seat 13, then install the valve seat 13 into the inner hole of the floating hoop shell 11, and finally install the straightening ring 12 into the inside of the floating hoop shell 11.

[0061] In the present invention, the upper port of the valve seat 13 is provided with a countersunk hole, and the side wall of the countersunk hole is tapered. The countersunk hole at the upper port of the valve seat 13 increases the sealing gradient of the seat-hanging self-locking rubber plug to the valve hole on the valve seat 13, and the side wall of the countersunk hole is tapered, which increases the sealing surface of the seat-hanging self-locking rubber plug to the countersunk hole, and further improves the sealing between the seat-hanging self-locking rubber plug and the valve seat 13. The valve hole in the valve seat 13 adopts a straight hole structure, which effectively reduces the accumulation of silt and improves the reliability of the device. In the present invention, the valve seat 13 is directly or indirectly connected to the lower part of the floating hoop shell 11, and the valve seat 13 is provided with a valve hole, and the lower port of the valve hole is a bell mouth.

[0062] In the present invention, an annular conical surface is provided in the upper port and the lower port of the righting ring 12, respectively. The annular conical surface in the core of the upper port and the lower port of the righting ring 12 forms a transitional constriction, which will not scratch the seat-hanging self-locking rubber plug passing through. The righting ring 12 is sleeved in the floating hoop shell 11, which is equivalent to reducing the inner diameter of the floating hoop shell 11 at this point, and can right the seat-hanging self-locking rubber plug, so that the lower end of the seat-hanging self-locking rubber plug is facing the valve seat 13, and the valve hole on the valve seat 13 is kept blocked.

[0063] In the present invention, the structure of the rubber valve 14 is determined according to the needs. The rubber valve 14 includes two parts, a rubber valve body and a straight rod. The straight rod is arranged at the lower end of the rubber valve body. The left and right sides of the rubber valve body are provided with pointed protrusions, and the upper surface is arc-shaped. The upper end of the rubber valve 14 covers the valve hole of the valve seat 13 upward, and the lower end of the rubber valve 14 is provided with a straight rod, which passes downward through the through hole on the spring cover 17; the floating hoop spring 16 is mounted on the straight rod, and the upper end of the floating hoop spring 16 is pressed against the rubber valve body of the rubber valve 14, and the lower end is pressed against the spring cover 17.

[0064] In the present invention, the spring cover 17 is cylindrical, and a through hole is provided at the bottom thereof. The side wall of the spring cover 17 is hollowed out, and the upper end of the spring cover 17 is connected to the lower end of the valve seat 13 .

[0065] A method for using a seat-mounted self-locking floating collar and a matching rubber plug device, the specific steps are:

[0066] Step 1: Install the self-locking floating collar between the required casing strings;

[0067] Step 2: insert the casing into the well and perform cementing operations;

[0068] Step 3: Before cementing and displacement, install the seat-hanging self-locking rubber plug into the casing string to displace cement slurry;

[0069] Step 4: When the seat-hanging self-locking rubber plug enters the seat-hanging self-locking floating hoop, the scraper ring 9 scrapes the mud and debris from the inner hole of the valve seat 14 in a circulating manner. Finally, when the pressure ring 10 reaches the bottom of the inner hole of the valve seat 13, the seat head 7 compresses the spring backward and contracts. The rubber plug body 1 pushes the seat ring 6 to expand along the conical surface of the seat head 7 to realize the seat self-locking. At the same time, the first sealing ring 9 realizes the channel sealing to achieve the seat sealing.

[0070] like Figure 3 and Figure 4 As shown, when the present invention is used, firstly, the seat-hanging self-locking floating collar of the present invention is installed between the 5-1 / 2" casing string, which can be used in conjunction with the floating shoe, and then the casing is strung into the well for cementing construction. Before cementing displacement, the seat-hanging self-locking rubber plug of the present invention is installed in the casing string for displacement cement slurry construction. When the seat-hanging self-locking rubber plug enters the seat-hanging self-locking floating collar, the scraper ring 9 scrapes the circulating mud debris on the inner hole of the valve seat 14. Finally, when the pressure ring 10 reaches the bottom of the inner hole of the valve seat 13, the seat hanging head 7 compresses the spring backward and contracts, and the rubber plug body 1 pushes the seat hanging ring 6 to expand along the cone surface of the seat hanging head 7 to realize the seat hanging self-locking. At the same time, the double inverted sealing ring 9 realizes the channel sealing, achieves the seat hanging sealing effect, and the reverse flow is quickly cut off, and the cement plug is prevented from being left in the casing at the bottom of the well. The use method of the whole device is simple to operate and has high safety.

[0071] In the present invention, the inner hole of the valve seat 13 is a round through hole with high surface finish. The present invention is simple to operate and highly safe. After the rubber plug is self-locked, the positive pressure of the floating hoop is greater than 65MPa.

[0072] The invention effectively solves the technical problems of unstable pressure and rubber plug floating caused by rubber plug wear in oil and gas horizontal wells, improves the positive pressure bearing capacity of the casing string after collision pressure, and meets the requirements of completion and fracturing on wellbore sealing.

[0073] The above examples are merely illustrative of the present invention and do not constitute a limitation on the protection scope of the present invention. Any design that is the same or similar to the present invention belongs to the protection scope of the present invention. The device structure and method steps not described in detail in the present invention are all prior art and will not be further described in the present invention.

Claims

1. A seat-mounted self-locking floating hoop and matching rubber plug device, characterized in that: The invention comprises a seat-hanging self-locking floating hoop and a seat-hanging self-locking rubber plug, wherein the seat-hanging self-locking rubber plug is connected to the seat-hanging self-locking floating hoop via a seat-hanging ring (6); the seat-hanging self-locking rubber plug comprises a rubber plug body (1), a spring limiting shaft (2), a rubber plug spring (3), a fixing ring (4), a seat-hanging head (7), a mud scraping ring (8) and a pressure ring (10); the pressure ring (10) and the mud scraping ring (8) are sleeved on the outside of the lower end of the seat-hanging head (7) in sequence from bottom to top; the fixing ring (4) is sleeved on the upper end of the seat-hanging head (7), and the lower part of the spring limiting shaft (2) is located on the fixing ring (10). 4), the rubber plug spring (3) is arranged between the spring limiting shaft (2) and the fixing ring (4); the fixing ring (4) is connected to the rubber plug body (1); the seat hanging head (7) comprises a seat hanging head body (701) and a circular ring protrusion (702), the circular ring protrusion (702) is located at the center of the upper end of the seat hanging head body (701), and the maximum outer diameter of the circular ring protrusion (702) is smaller than the outer diameter of the upper end of the seat hanging head body (701); the lower end of the circular ring protrusion (702) and the upper end of the seat hanging head body (701) form an annular space; the seat hanging head body ( 701) is a cylindrical structure with a larger bottom and a smaller top; the lower end of the seat hanging head body (701) is provided with two stepped external threads; the two external threads are respectively connected to the corresponding pressure ring (10) and the scraper ring (8); the upper end outer wall of the seat hanging head body (701) is sleeved with a seat hanging ring (6); the seat hanging self-locking floating hoop comprises a floating hoop shell (11), a straightening ring (12), a valve seat (13), a rubber hanging valve (14), a floating hoop spring (16) and a spring cover (17); the floating hoop spring (16) is arranged on the rubber hanging valve (14), and the rubber hanging valve (17) is provided on the floating hoop spring (16). The lower end of the rubber valve (14) is connected to the spring cover (17), the upper end of the rubber valve (14) is connected to the valve seat (13), the valve seat (13) is arranged in the righting ring (12), and the righting ring (12) is located in the floating hoop shell (11); the valve seat (13) and the floating hoop shell (11) are sealed and connected via a second sealing ring (15); a plurality of slide grooves (703) are formed on the side wall of the circular protrusion (702); the slide grooves (703) on the circular protrusion (702) are fixed via corresponding pin holes on the fixed shaft (5) and the fixed ring (4).

2. A seat-mounted self-locking floating collar and matching rubber plug device according to claim 1, characterized in that: The spring limiting shaft (2) comprises a limiting shaft body and a limiting plate, wherein the limiting plate is located at the upper end of the limiting shaft body, and the outer diameter of the limiting plate is greater than the outer diameter of the lower end shaft of the spring limiting shaft (2).

3. A seat-mounted self-locking floating collar and matching rubber plug device according to claim 1, characterized in that: A circular hole is formed at the lower end of the rubber plug body (1), a fixing ring (4) is arranged in the circular hole, the outer diameter of the limiting plate of the spring limiting shaft (2) arranged in the fixing ring (4) matches the size of the circular hole, and the limiting plate of the spring limiting shaft (2) is in contact with and connected to the bottom surface of the circular hole.

4. A seat-mounted self-locking floating collar and matching rubber plug device according to claim 1, characterized in that: The seat hanging head (7) is provided with a sealing groove (704), and a first sealing ring (9) is installed in the sealing groove (704).

5. The method for using the seat-mounted self-locking floating collar and the matching rubber plug device according to any one of claims 1 to 4, characterized in that: The specific steps are: Step 1: Install the self-locking floating collar between the required casing strings; Step 2: insert the casing into the well and perform cementing operations; Step 3: Before cementing and displacement, install the seat-hanging self-locking rubber plug into the casing string to displace cement slurry; Step 4: When the seat-hanging self-locking rubber plug enters the seat-hanging self-locking floating hoop, the scraper ring (8) scrapes the mud and debris from the inner hole of the valve seat (13) in a circulating manner. Finally, when the pressure ring (10) reaches the bottom of the inner hole of the valve seat (13), the seat-hanging head (7) compresses the rubber plug spring backwards and the rubber plug body (1) pushes the seat-hanging ring (6) to expand along the conical surface of the seat-hanging head (7) to realize the seat-hanging self-locking. At the same time, the first sealing ring (9) realizes the channel sealing to achieve the seat-hanging sealing.

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