Self-grouting float collar and using method
Through the dual-valve structure of metal ball valve and rubber mushroom valve, the seal failure problem of floating hoop shoes under high temperature and high pressure and corrosive gas conditions is solved, and the pressure balance and construction efficiency are improved during self-grouting.
Patent Information
- Application Number
- CN202311795978.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-25
- Publication Date
- 2025-07-04
AI Technical Summary
Existing floating hoop shoes frequently fail under high temperature and high pressure and corrosive gas conditions, resulting in reduced sealing performance, and there are problems of cementing cement backflow and mud accumulation during self-grouting, which affects the stability of the wellbore and construction efficiency.
The dual-valve structure of metal ball valve and rubber mushroom valve is adopted. The metal ball valve is resistant to high temperature and corrosion. The mushroom valve is made of high temperature and corrosion resistant rubber materials. The dual-valve structure channel is opened before and during the well downward process to achieve self-grouting. After the casing is lowered to the design depth, the dual-valve structure is closed to avoid backflow of cement cement.
The pressure balance between the inner and outer casing under complex working conditions is achieved, the drilling rig load is reduced, the cement cement backflow is avoided, and the construction efficiency and wellbore stability is improved.
Smart Images
Figure CN120251144A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of oil and gas drilling and completion, and particularly relates to a self-grouting float collar and a using method thereof. Background Art
[0002] In order to ensure the safety of various pipe strings and tools lowered into the well and maintain the stability of the wellbore, it is necessary to consider the internal and external pressure balance of the pipe strings and tools and the upward return velocity of the mud in the wellbore annulus. The existing solution is to install a float collar and a float shoe at the lower part of the casing to prevent the cement slurry from flowing back after cementing is completed.
[0003] Conventional float collars and float shoes do not have an automatic grouting function. It is necessary to manually pour mud into the casing from the wellhead as the casing is lowered to achieve the dynamic balance of the internal and external pressures of the casing. The advantage is that it can reduce the weight of the casing string, thereby reducing the load on the drilling rig. The disadvantages are as follows: First, the downhole agitation pressure is high during the casing running process, which is likely to cause lost circulation; second, the upward return velocity of the mud in the wellbore annulus is high during the casing running process, which seriously scours the wellbore wall and is not conducive to the stability of the wellbore. Problems such as non-return of mud during the casing running process and difficulty in starting the pump after the casing is run are often encountered; third, the mud filling is discontinuous. During mud filling, the casing running operation must be stopped, and accidents such as stuck casing are likely to occur; fourth, the reliability of mud filling is poor, and it is difficult to meet the requirement of filling each time, which is likely to cause excessive hollowing and thus generate too large a differential pressure between the internal and external liquid columns of the casing; fifth, the production efficiency is low, the construction time is long, which is not conducive to downhole safety, especially for high-pressure gas wells.
[0004] The existing self-grouting float collars and float shoes automatically pour mud into the casing as the casing is lowered into the well, which can balance the internal and external pressures of the casing. However, they frequently fail under the working conditions of high temperature and high pressure and corrosive gases. The main reasons are as follows: First, high temperature reduces the performance of the housing and components and cannot meet the index requirements; second, when there is carbon dioxide or hydrogen sulfide gas, it will corrode the sealing rubber, cast iron, and aluminum alloy materials, resulting in a decrease in sealing performance and causing sealing failure; third, during cyclic operation, a large amount of mud accumulates between the rod hole and the guide rod, affecting the normal reset of the guide rod and causing the anti-backpressure effect of the float collar and float shoe to fail. Summary of the Invention
[0005] In view of the above problems, the object of the present invention is to provide a self-grouting float collar and a using method thereof. The self-grouting float collar and float shoe adopt a double-valve structure of a metal ball valve and a rubber mushroom valve. The metal ball valve is resistant to high temperature and corrosion, meeting the performance requirements of the float collar and float shoe for complex working conditions; the rubber mushroom valve is made of rubber material resistant to high temperature and corrosion, playing a dual guarantee role. Before and during the casing running, the channels of the double-valve structure are opened to achieve self-grouting. When the casing reaches the designed depth and the bump pressure is completed, the channels of the double-valve structure are closed to prevent the backflow of the cement slurry for cementing.
[0006] The technical solution of the present invention lies in: a self-grouting float collar, including a float collar and float shoe body. The interior of the float collar and float shoe body is hollow, and a metal ball valve and a mushroom valve are successively arranged on the inner wall of the hollow from top to bottom. The metal ball valve includes a metal ball valve seat, a ball valve body is arranged below the metal ball valve seat, the ball valve body is connected with a valve core trunnion, gears are respectively arranged at both ends of the valve core trunnion, and the gears are located in the gap between the inner wall of the float collar and float shoe body and the metal ball valve seat. The gears are connected with a valve rod, and fixed teeth meshing with the gears are arranged on the surface of the valve rod. A hydraulic piston and a check valve are successively arranged in the gap between the float collar and float shoe body above the valve rod and the metal ball valve seat. The mushroom valve includes a mushroom valve seat, a mushroom valve body is arranged below the mushroom valve seat, a mushroom valve spring seat is arranged below the mushroom valve body, a mushroom valve spring is arranged in the mushroom valve spring seat, the mushroom valve spring is fixedly connected with the mushroom valve body, and a mushroom valve limit pin is further arranged below the mushroom valve body.
[0007] Mating teeth are arranged on the inner wall of the float collar and float shoe body below the gears, and teeth matching the mating teeth are arranged on the lower part of the valve rod.
[0008] An upper joint is arranged on the upper part of the float collar and float shoe body, and a lower joint is arranged on the lower part.
[0009] A slideway is arranged on the inner wall of the float collar and float shoe body, and the valve rod is located in the slideway.
[0010] The material of the mushroom valve body is rubber, and the top of the mushroom valve body is arc-shaped.
[0011] The gears drive the valve core trunnion and the ball valve body to rotate. When the gears rotate 1 / 4 turn, the ball valve body rotates 90°.
[0012] A using method of a self-grouting float collar, using the self-grouting float collar as described above, includes the following steps: S1: Install the self-grouting float collar at the lower end of the casing string, separated from the float shoe by 1 or 2 casings, and lower it into the well to the designed position of the completion string along with the casing string. During the process of lowering the casing, the metal ball valve and the mushroom valve are in the open position, and the drilling fluid enters the inside of the string from the float shoe to achieve self-grouting; S2: After the casing is lowered to the designed position, a rubber plug is dropped to apply pressure. After the pressure application is qualified, continue to apply pressure, and the metal ball valve and the mushroom valve are closed to ensure that the cement slurry for well cementing does not flow back. The specific process is as follows: S21: First, the high pressure generated after pressure application opens the check valve of the metal ball valve, and the drilling fluid or displacement fluid flows through the check valve, pushing the hydraulic piston downward, causing the valve rod to move downward, driving the gears to rotate. When the gears rotate 1 / 4 turn, the ball valve body rotates 90° and contacts the metal ball valve seat to achieve the closing of the metal ball valve; S22: During the downward movement of the valve stem, the lower end of the valve stem contacts and cuts off the mushroom valve limit pin. Under the action of the mushroom valve spring, the mushroom valve body is forced to reset and return to the mushroom valve seat, closing the mushroom valve.
[0013] The technical effects of the present invention are as follows: 1. The present invention adopts a double-valve structure of a metal ball valve and a rubber mushroom valve. The metal ball valve is resistant to high temperature and corrosion, meeting the performance requirements of the float collar and float shoe for complex working conditions; the rubber mushroom valve is made of rubber material resistant to high temperature and corrosion, playing a dual guarantee role. Before and during the wellbore operation, the channels of the double-valve structure are opened to achieve self-grouting. When the casing reaches the designed depth and the bump pressure is completed, continuous pressurization is applied to rotate and reset the upper metal ball valve into the ball seat and lock it, achieving metal-to-metal sealing; the limit pin of the lower rubber mushroom valve is cut off, and its mushroom valve is reset to the valve seat under the action of its spring, achieving rubber-to-valve seat sealing, and the channels of the double-valve structure are closed, avoiding the backflow of cement slurry during cementing; 2. The present invention drives the valve stem by a hydraulic piston to push the gear to close the metal ball valve. It has a fully mechanical structure, simple structure, and low failure rate of the tool, meeting the performance requirements of the float collar and float shoe for complex working conditions; 2. During the casing running process of the self-grouting string structure of the present invention, self-grouting is carried out throughout the process, balancing the pressure inside and outside the casing, reducing the weight of the casing string, and thus reducing the load on the drilling rig.
[0014] The following will be further described with reference to the accompanying drawings. Description of the Drawings
[0015] Figure 1 It is a schematic structural diagram of the self-grouting state of a self-grouting float collar according to an embodiment of the present invention.
[0016] Figure 2 It is a schematic structural diagram of the double-valve reset state of a self-grouting float collar according to an embodiment of the present invention.
[0017] Reference numerals: 1 - upper sub, 2 - check valve, 3 - hydraulic piston, 4 - gear, 5 - mushroom valve seat, 6 - mushroom valve body, 7 - mushroom valve spring, 8 - metal ball valve seat, 9 - valve stem, 10 - spool trunnion, 11 - ball valve body, 12 - buttress thread, 13 - mushroom valve limit pin, 14 - mushroom valve spring seat, 15 - lower sub, 16 - float collar and float shoe body. Detailed Description of the Invention Embodiment 1
[0018] As Figure 1 、 Figure 2As shown in the figure, a self-grouting float collar includes a float collar and float shoe body 16. The interior of the float collar and float shoe body 16 is hollow, and a metal ball valve and a mushroom valve are successively arranged on the inner wall of the hollow from top to bottom. The metal ball valve includes a metal ball valve seat 8. A ball valve body 11 is arranged below the metal ball valve seat 8. The ball valve body 11 is connected with a valve core trunnion 10. Gears 4 are respectively arranged at both ends of the valve core trunnion 10. The gears 4 are located in the gap between the inner wall of the float collar and float shoe body 16 and the metal ball valve seat 8. The gears 4 are connected with a valve rod 9. Fixed teeth meshing with the gears 4 are arranged on the surface of the valve rod 9. A hydraulic piston 3 and a check valve 2 are successively arranged in the gap between the float collar and float shoe body 16 and the metal ball valve seat 8 above the upper part of the valve rod 9. The mushroom valve includes a mushroom valve seat 5. A mushroom valve body 6 is arranged below the mushroom valve seat 5. A mushroom valve spring seat 14 is arranged below the mushroom valve body 6. A mushroom valve spring 7 is arranged in the mushroom valve spring seat 14. The mushroom valve spring 7 is fixedly connected with the mushroom valve body 6. A mushroom valve limit pin 13 is also arranged below the mushroom valve body 6.
[0019] During the actual use process, the invention is installed at the lower end of the casing string, separated from the float shoe by 1 or 2 casings, and is lowered into the well to the designed position of the completion string along with the casing string. During the casing lowering process, the metal ball valve and the mushroom valve are in the open position, and the drilling fluid enters the inside of the string from the float shoe to achieve self-grouting. After the casing is lowered to the designed position, a rubber plug is dropped and pressed. After the pressing is qualified, continue to apply pressure. The metal ball valve and the mushroom valve are closed to ensure that the cement slurry for well cementing does not flow back. The specific process is as follows: First, the high pressure generated after pressing opens the check valve 2 of the metal ball valve, and the drilling fluid or displacement fluid flows through the check valve 2, pushing the hydraulic piston 3 downward, causing the valve rod 9 to move downward, driving the gear 4 to rotate. The gear 4 rotates 1 / 4 turn, and the ball valve body 11 rotates 90°, contacting the metal ball valve seat 8 to achieve the closing of the metal ball valve. During the downward movement of the valve rod 9, the lower end of the valve rod 9 contacts and cuts off the mushroom valve limit pin 13. Under the action of the mushroom valve spring 7, the mushroom valve body 6 is forced to reset and return to the mushroom valve seat 5 to achieve the closing of the mushroom valve. Through the double-valve structure of the metal ball valve and the rubber mushroom valve, the metal ball valve is resistant to high temperature and corrosion, meeting the performance requirements of the float collar and float shoe for complex working conditions; the rubber mushroom valve is made of rubber material resistant to high temperature and corrosion, playing a double guarantee role. Before and during the well lowering process, the channels of the double-valve structure are opened to achieve self-grouting. When the casing reaches the designed depth and the pressing is completed, continue to apply pressure, and the channels of the double-valve structure are closed to avoid the backflow of the well cementing cement slurry. Embodiment 2
[0020] Preferably, on the basis of Embodiment 1, in this embodiment, preferably, a dovetail 12 is arranged on the inner wall of the float collar and float shoe body 16 below the gear 4, and teeth matching the dovetail 12 are arranged on the lower part of the valve rod 9.
[0021] During actual use, on the inner wall of the float collar and float shoe body 16 of the present invention, there is a buttress thread 12 below the gear 4, and teeth matching the buttress thread 12 are provided at the lower part of the valve stem 9, which is convenient for controlling the movement stroke of the valve stem. The buttress thread on the valve stem is closely matched with the buttress thread inside the housing, preventing other actions of the ball valve and affecting the sealing performance of the ball valve. Embodiment 3
[0022] Preferably, on the basis of Embodiment 1 or Embodiment 2, in this embodiment, preferably, an upper sub 1 is provided at the upper part of the float collar and float shoe body 16, and a lower sub 15 is provided at the lower part.
[0023] During actual use, an upper sub 1 is provided at the upper part of the float collar and float shoe body 16 of the present invention, and a lower sub 15 is provided at the lower part, which is convenient for connecting with the upper casing string and the lower casing. Embodiment 4
[0024] Preferably, on the basis of Embodiment 1 or Embodiment 3, in this embodiment, preferably, a slideway is provided on the inner wall of the float collar and float shoe body 16, and the valve stem 9 is located in the slideway.
[0025] During actual use, a slideway is provided on the inner wall of the float collar and float shoe body 16 of the present invention, and the valve stem 9 is located in the slideway. The slideway is convenient for defining the movement direction of the valve stem 9. Embodiment 5
[0026] Preferably, on the basis of Embodiment 1 or Embodiment 4, in this embodiment, preferably, the material of the mushroom valve body 6 is rubber, and the top of the mushroom valve body 6 is arc-shaped.
[0027] During actual use, the material of the mushroom valve body 6 of the present invention is rubber, preferably a rubber material with high temperature resistance and corrosion resistance, which provides double protection for the sealing of the metal ball valve. Embodiment 6
[0028] Preferably, on the basis of Embodiment 1 or Embodiment 5, in this embodiment, preferably, the gear 4 drives the spool trunnion 10 and the ball valve body 11 to rotate. When the gear 4 rotates 1 / 4 turn, the ball valve body 11 rotates 90°.
[0029] During actual use, the gear 4 of the present invention drives the spool trunnion 10 and the ball valve body 11 to rotate. When the gear 4 rotates 1 / 4 turn, the ball valve body 11 rotates 90°. Rotating the gear 4 by 1 / 4 turn can achieve the closing of the metal ball valve, and the operation is simple and convenient. Embodiment 7
[0030] A method for using a self-grouting float collar, using a self-grouting float collar as described above, includes the following steps: S1: Install the self-grouting float collar at the lower end of the casing string, separated from the float shoe by 1 or 2 casing joints, and lower it into the well to the position required by the completion string design. During the casing running process, the metal ball valve and the mushroom valve are in the open position, and the drilling fluid enters the inside of the string from the float shoe to achieve self-grouting. S2: After the casing is lowered to the designed position, drop a plug to make a bump pressure. After the bump pressure is qualified, continue to apply pressure, and the metal ball valve and the mushroom valve will close to ensure that the cement slurry for cementing does not flow back. The specific process is as follows: S21: First, the high pressure generated after the bump pressure opens the check valve 2 of the metal ball valve, and the drilling fluid or displacement fluid flows through the check valve 2, pushing the hydraulic piston 3 downward, causing the valve stem 9 to move downward, driving the gear 4 to rotate. The gear 4 rotates 1 / 4 turn, and the ball valve body 11 rotates 90°, contacting the metal ball valve seat 8 to achieve the closing of the metal ball valve. S22: During the downward movement of the valve stem 9, the lower end of the valve stem 9 contacts and cuts off the mushroom valve limit pin 13. Under the action of the mushroom valve spring 7, the mushroom valve body 6 is forced to reset and return to the mushroom valve seat 5 to achieve the closing of the mushroom valve.
[0031] As described above, it is only the preferred specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.
Claims
1. A self-grouting float collar, characterized in that: It includes a float collar and float shoe body (16). The inside of the float collar and float shoe body (16) is hollow. Inside the hollow inner wall, a metal ball valve and a mushroom valve are successively arranged from top to bottom. The metal ball valve includes a metal ball valve seat (8). Below the metal ball valve seat (8), a ball valve body (11) is provided. The ball valve body (11) is connected with a spool trunnion (10). At both ends of the spool trunnion (10), gears (4) are respectively provided. The gears (4) are located in the gap between the inner wall of the float collar and float shoe body (16) and the metal ball valve seat (8). The gears (4) are connected with a valve rod (9). On the surface of the valve rod (9), fixed teeth meshing with the gears (4) are provided. In the gap between the float collar and float shoe body (16) and the metal ball valve seat (8) above the valve rod (9), a hydraulic piston (3) and a check valve (2) are successively arranged. The mushroom valve includes a mushroom valve seat (5). Below the mushroom valve seat (5), a mushroom valve body (6) is provided. Below the mushroom valve body (6), a mushroom valve spring seat (14) is provided. Inside the mushroom valve spring seat (14), a mushroom valve spring (7) is provided. The mushroom valve spring (7) is fixedly connected with the mushroom valve body (6). Below the mushroom valve body (6), a mushroom valve limit pin (13) is also provided.
2. The self-grouting float collar according to claim 1, characterized in that: On the inner wall of the float collar and float shoe body (16) below the gears (4), a sawtooth (12) is provided. On the lower part of the valve rod (9), teeth matching the sawtooth (12) are provided.
3. The self-grouting float collar according to claim 1, characterized in that: On the upper part of the float collar and float shoe body (16), an upper sub (1) is provided, and on the lower part, a lower sub (15) is provided.
4. The self-grouting float collar according to claim 1, wherein: On the inner wall of the float collar and float shoe body (16), a slideway is provided, and the valve rod (9) is located in the slideway.
5. The self-grouting float collar according to claim 1, wherein: The material of the mushroom valve body (6) is rubber, and the top of the mushroom valve body (6) is arc-shaped.
6. The self-grouting float collar according to claim 1, wherein: The gears (4) drive the spool trunnion (10) and the ball valve body (11) to rotate. When the gears (4) rotate a quarter of a turn, the ball valve body (11) rotates 90°.
7. A method for using a self-grouting float collar, which uses a self-grouting float collar as described in claim 1, characterized in that: It includes the following steps: S1: Install the self-grouting float collar at the lower end of the casing string, separated from the float shoe by 1 or 2 casings, and lower it into the well to the designed position of the completion string with the casing string. During the process of lowering the casing, the metal ball valve and the mushroom valve are in the open position, and the drilling fluid enters the inside of the string from the float shoe to achieve self-grouting. S2: After the casing is lowered to the designed position, a rubber plug is dropped to apply pressure. After the pressure application is qualified, continue to apply pressure, and the metal ball valve and the mushroom valve are closed to ensure that the cement slurry for cementing does not flow back. The specific process is as follows: S21: First, the high pressure generated after the pressure application opens the check valve (2) of the metal ball valve. The drilling fluid or displacement fluid flows through the check valve (2), pushes the hydraulic piston (3) to descend, causes the valve rod (9) to descend, drives the gears (4) to rotate. When the gears (4) rotate a quarter of a turn, the ball valve body (11) rotates 90° and contacts the metal ball valve seat (8) to achieve the closing of the metal ball valve. S22: During the descending process of the valve rod (9), the lower end of the valve rod (9) contacts and cuts off the mushroom valve limit pin (13). Under the action of the mushroom valve spring (7), the mushroom valve body (6) is forced to reset and return to the mushroom valve seat (5) to achieve the closing of the mushroom valve.