A float collar for cementing and drilling equipment

Abstract

The application discloses a floating collar for well cementation, which comprises an outer cylinder and a drop-in valve body arranged coaxially, the outer cylinder is fixedly connected with and leads through a casing, the drop-in valve body is internally provided with a through hole penetrating in the axial direction, the inner wall of the outer cylinder is provided with an outer locking structure, and the outer wall of the drop-in valve body is provided with an inner locking structure; before well cementation construction, the drop-in valve body is pumped into the inner part of the outer cylinder, and the inner locking structure and the outer locking structure are in contact and locked with each other to fix the relative position of the drop-in valve body and the outer cylinder, and the drop-in valve body is internally provided with a one-way mechanism for limiting the flow of liquid in the well. The drop-in valve body is not installed during the drilling process, but is installed again before well cementation, so that the drop-in valve body is prevented from being eroded and damaged, cement slurry backflow during well cementation is prevented, safety hidden dangers are eliminated, and stability, safety and high efficiency are improved. The application further discloses a drilling equipment comprising the floating collar for well cementation.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of drilling, in particular to a float collar for cementing. BACKGROUND

[0002] In the process of casing drilling, the casing is used as a part of the drill string throughout the drilling process, and the casing is also used in the process of cementing. In the process of cementing, the float collar in the casing acts as a check valve, allowing the liquid in the well to flow from the head end to the tail end through the float collar, and preventing the backflow of cement slurry, thereby ensuring the safety of the cementing effect.

[0003] In the conventional cementing process, the float collar is lowered into the well bottom with the cementing casing, and then drilling operations are carried out. With the drilling of the drill bit, the working environment of the float collar is very harsh, and the long-term high-flow drilling fluid passing through the float collar has a significant scouring effect, and the solid particles in the drilling fluid also have a continuous erosion effect on the float collar. The float collar is damaged during drilling, and does not have the function of a check valve, causing the float collar to fail and preventing the backflow of cement slurry during cementing, which poses a safety hazard. At the same time, the float collar still needs to be drilled out during subsequent drilling, which takes a long time.

[0004] Therefore, how to provide a stable and efficient float collar for cementing is a technical problem that those skilled in the art need to solve at present. SUMMARY

[0005] The purpose of the present application is to provide a float collar for cementing, which does not install a drop-in valve body during drilling, but only installs a drop-in valve body before cementing, thereby avoiding erosion and damage to the drop-in valve body, and improving stability, safety and efficiency. Another object of the present application is to provide a drilling device comprising the above-mentioned float collar for cementing.

[0006] To solve the above technical problems, the present application provides a float collar for cementing, comprising an outer cylinder and a drop-in valve body arranged coaxially, the outer cylinder is fixedly connected and conducts the casing, the drop-in valve body is provided with an axial through hole, the inner wall of the outer cylinder is provided with an outer locking structure, the outer wall of the drop-in valve body is provided with an inner locking structure, the drop-in valve body is pumped into the inner part of the outer cylinder before cementing construction, and the inner locking structure and the outer locking structure are in contact and locked with each other to fix the relative position of the drop-in valve body and the outer cylinder, and the drop-in valve body is provided with a one-way mechanism for limiting the flow of liquid in the well.

[0007] Preferably, the one-way mechanism comprises a base and a sealing rod arranged coaxially, a first end of the base is connected to the end of the drop-in valve body and a bottom plate at the end of the base is provided with circulation holes for the liquid in the well to flow out, the sealing rod is installed inside the base, a sealing head is arranged at the first end of the sealing rod, a spring is sleeved on the outer periphery of the sealing rod, and the two ends of the spring are respectively abutted against the sealing head and the base, the spring pushes the sealing head to tightly abut against the end opening of the through hole in the drop-in valve body, and the liquid in the well pushes the sealing head to move away from the end opening of the through hole in the drop-in valve body during cementing work.

[0008] Preferably, a tapered surface is arranged at the first end of the sealing head, and a rubber layer is arranged on the first end of the sealing head, and the rubber layer can cooperate with the tapered surface at the end opening of the through hole in the drop-in valve body.

[0009] Preferably, a guide cylinder is arranged in the middle of the bottom plate at the end of the base, the sealing rod passes through the guide cylinder, the sealing rod and the guide cylinder are connected by a pin before cementing construction, and the liquid in the well pushes the sealing rod to move relative to the guide cylinder to cut the pin during cementing work.

[0010] Preferably, the circulation holes are specifically waist-shaped holes, four waist-shaped holes are arranged around the guide cylinder, and the sum of the areas of the circulation holes is greater than the area of the end opening of the through hole in the drop-in valve body.

[0011] Preferably, the outer locking structure and the inner locking structure are specifically an outer sawtooth-shaped groove and an inner sawtooth-shaped groove arranged in sequence along the axial direction, a sealing ring is arranged below the inner locking structure, and the sealing ring is in contact with the smooth inner wall below the outer locking structure to form a pressure sealing structure.

[0012] Preferably, an inner positioning step is arranged below the sealing ring, an outer positioning step is arranged at the corresponding position of the inner wall of the outer cylinder, and the inner positioning step is abutted against the outer positioning step to limit the movement of the drop-in valve body to the end.

[0013] Preferably, a retreat-stop ring is arranged below the inner positioning step, a retreat-stop groove is arranged below the outer positioning step, and the retreat-stop ring can be clamped into the retreat-stop groove.

[0014] Preferably, the drop-in valve body, the base and the sealing rod are specifically soluble metal materials that can be dissolved in the liquid in the well.

[0015] The application also provides a drilling equipment comprising a casing and a cementing float collar connected to the casing, and the cementing float collar is specifically any one of the cementing float collars described above.

[0016] The application provides a floating collar for well cementing, which comprises an outer cylinder and a drop-in valve body arranged coaxially, the outer cylinder is fixedly connected with and conducts a casing, the drop-in valve body is internally provided with an axial through hole, the inner wall of the outer cylinder is provided with an outer locking structure, and the outer wall of the drop-in valve body is provided with an inner locking structure; before well cementing construction, the drop-in valve body is pumped into the inner part of the outer cylinder, and the inner locking structure and the outer locking structure are in contact and locked with each other to fix the relative position of the drop-in valve body and the outer cylinder, and the drop-in valve body is internally provided with a one-way mechanism for limiting the flow of liquid in the well.

[0017] The outer cylinder is directly installed on the casing, and the inner diameter of the outer cylinder is consistent with the casing, so that the outer cylinder and the casing are used as a drill string in drilling work, the drop-in valve body is pumped into the inner part of the outer cylinder before well cementing construction, the two are locked and assembled into an integral whole through the locking structure, and the flow direction of the liquid in the well is controlled through the one-way mechanism, so that the function of the one-way valve is realized. The outer cylinder and the drop-in valve body adopt a split structure, the drop-in valve body is not installed during drilling, and is only installed before well cementing, so that the drop-in valve body is prevented from being eroded and damaged, cement slurry backflow in the well cementing process is prevented, safety hazards are eliminated, and stability, safety and efficiency are improved.

[0018] The application also provides a drilling equipment comprising the floating collar for well cementing, since the floating collar for well cementing has the technical effects described above, the drilling equipment should also have the same technical effects, and will not be described in detail here. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 A structural schematic view of one specific embodiment of the floating collar for well cementing provided by the application;

[0020] Figure 2 A structural schematic view of the outer cylinder in one specific embodiment of the floating collar for well cementing provided by the application;

[0021] Figure 3 A structural schematic view of the drop-in valve body in one specific embodiment of the floating collar for well cementing provided by the application;

[0022] Figure 4 A structural schematic view of the base in one specific embodiment of the floating collar for well cementing provided by the application;

[0023] Figure 5 An upper view schematic view of the base in one specific embodiment of the floating collar for well cementing provided by the application.

[0024] The outer cylinder 1, the outer sawtooth-shaped groove 11, the smooth inner wall 12, the outer positioning step 13, the retreat-stop groove 14, the drop-in valve body 2, the inner sawtooth-shaped groove 21, the inner positioning step 22, the base 3, the guide cylinder 31, the circulation hole 32, the sealing rod 4, the spring 5, the rubber layer 6, the pin 7, the sealing ring 8 and the retreat-stop ring 9. DETAILED DESCRIPTION

[0025] The core of the present application is to provide a floating collar for well cementation, without installing a drop-in valve body during drilling, only installing the drop-in valve body before well cementation, avoiding the erosion and damage of the drop-in valve body, and improving stability, safety and efficiency. Another core of the present application is to provide a drilling device comprising the floating collar for well cementation.

[0026] In order for those skilled in the art to better understand the present application, the present application will be further described in detail below in combination with the drawings and specific embodiments.

[0027] Please refer to Figures 1 to 5 , Figure 1 The structural schematic diagram of one specific embodiment of the floating collar for well cementation provided by the present application; Figure 2 The structural schematic diagram of the outer cylinder in one specific embodiment of the floating collar for well cementation provided by the present application; Figure 3 The structural schematic diagram of the drop-in valve body in one specific embodiment of the floating collar for well cementation provided by the present application; Figure 4 The structural schematic diagram of the base in one specific embodiment of the floating collar for well cementation provided by the present application; Figure 5 The upper view schematic diagram of the base in one specific embodiment of the floating collar for well cementation provided by the present application.

[0028] The specific embodiment of the present application provides a floating collar for well cementation, comprising an outer cylinder 1 and a drop-in valve body 2 arranged coaxially, the outer cylinder 1 is fixedly connected and conducts a casing, the outer cylinder 1 is a cylindrical structure, the first end and the last end of the outer cylinder 1 are provided with threaded structures, which are fixed in the middle part of the casing through the threaded structures, of course, other connection methods can also be used to make the outer cylinder 1 and the casing integrated, the inner diameter of the outer cylinder 1 is consistent with the casing, so that the outer cylinder 1 and the casing are used together as a drill string in drilling work, wherein the first end and the last end of each component are defined according to the flow direction of the liquid, the upper end is the first end and the lower end is the last end in each drawing.

[0029] Further, the drop-in valve body 2 is a reverse conical structure, the upper part has a large outer diameter, and the lower part has a small outer diameter, the drop-in valve body 2 is provided with a through hole penetrating in the axial direction inside, the outer cylinder 1 is provided with an outer locking structure in the middle part of the inner wall, the drop-in valve body 2 is provided with an inner locking structure on the outer wall of the upper end, before well cementation construction, the drop-in valve body 2 is pumped into the inside of the outer cylinder 1, and the inner locking structure and the outer locking structure are in contact and locked with each other to fix the relative position of the drop-in valve body 2 and the outer cylinder 1, the drop-in valve body 2 cannot move upward any more, the drop-in valve body 2 is provided with a one-way mechanism for limiting the flow of liquid in the well, so that the liquid in the well can only flow from the upper end to the lower end, and cannot flow in the opposite direction, preventing the hydraulic pressure from flowing from the lower end to the upper end.

[0030] The outer cylinder 1 is directly mounted on the casing, and the inner diameter of the outer cylinder 1 is consistent with the casing, so that the outer cylinder 1 and the casing are used as a drill string in the drilling work, the drop-in valve body 2 is pumped into the inner part of the outer cylinder 1 before the cementing construction, the two are locked and assembled into a whole through the locking structure, and the flow direction of the liquid in the well is controlled through the one-way mechanism, so that the function of the one-way valve is realized. The outer cylinder 1 and the drop-in valve body 2 adopt a split structure, the drop-in valve body 2 is not installed during the drilling process, and the drop-in valve body 2 is installed only before the cementing, so that the drop-in valve body 2 is prevented from being eroded and damaged, the backflow of the cement slurry in the cementing process is prevented, the safety hidden danger is eliminated, and the stability, safety and efficiency are improved.

[0031] In the floating collar for cementing provided in the specific embodiment of the present application, the one-way mechanism comprises a base 3 and a sealing rod 4 arranged coaxially, the base 3 is a cylindrical structure, the upper end is open, and the lower end is provided with a bottom plate, the first end of the base 3 is provided with an internal thread, the tail end of the drop-in valve body 2 is provided with an external thread, the first end of the base 3 is connected and conducts the tail end of the drop-in valve body 2, and the bottom plate at the tail end of the base 3 is provided with a circulating hole 32 for the liquid in the well to flow out, the sealing rod 4 is installed in the inner part of the base 3, and the first end of the sealing rod 4 is provided with a sealing head, the upper part of the sealing rod 4 is conical, the lower part is cylindrical, the sealing rod 4 is sleeved with a spring 5 on the outer periphery, and the two ends of the spring 5 are respectively abutted with the sealing head and the bottom plate of the base 3, when there is no external force, the spring 5 pushes the sealing head to tightly seal the tail end opening of the through hole in the drop-in valve body 2. During the cementing work, the liquid in the well pushes the sealing head away from the tail end opening of the through hole in the drop-in valve body 2, so as to form a fluid passage, and the liquid in the well flows through the outer cylinder 1, the liquid passage and the base 3 in turn. When the cementing process is completed, the cementing liquid no longer applies pressure to the top of the sealing rod 4, and the spring 5 pushes the sealing rod 4 to move upward again to form a seal with the drop-in valve body 2. The cementing liquid cannot flow back to the upper part of the outer cylinder 1 from the lower part through the sealing rod 4, so that the safety of the cementing operation is ensured.

[0032] Specifically, the first end of the sealing head is provided with a conical surface, and the sealing head is covered with a rubber layer 6, which can cooperate with the conical surface at the tail end opening of the through hole in the drop-in valve body 2 to form a tight sealing structure.

[0033] In order to make the sealing rod 4 move smoothly, the middle part of the bottom plate at the tail end of the base 3 is provided with a guide cylinder 31, the sealing rod 4 passes through the guide cylinder 31, the guide cylinder 31 is provided with a radial through hole, and the side surface of the sealing rod 4 is provided with a positioning hole at the corresponding position, the sealing rod 4 and the guide cylinder 31 are connected through the radially extending pin 7 before the cementing construction, the pin 7 is inserted into the through hole and the positioning hole, and the base 3 and the sealing rod 4 are stably connected before the drop-in valve body 2 is sent into the outer cylinder 1. When the liquid in the well pushes the sealing rod 4 to move downward relative to the guide cylinder 31 during the cementing work, the pin 7 will be cut off.

[0034] The circulation holes 32 are specifically waist-shaped holes, four waist-shaped holes are arranged around the guide cylinder 31, the sum of the areas of the circulation holes 32 is greater than the area of the end opening of the through hole in the input valve body 2, and the shape, number and arrangement of the circulation holes 32 can be adjusted according to the situation, such as a plurality of uniformly arranged circular holes, which are all within the protection scope of the present application.

[0035] In the floating collar for cementing provided in the specific embodiments, the outer locking structure and the inner locking structure are specifically an outer sawtooth-shaped groove 11 and an inner sawtooth-shaped groove 21 arranged in sequence along the axial direction, and the two contact to form the first locking structure. A sealing ring 8 is arranged below the inner locking structure of the outer wall of the input valve body 1, and the sealing ring 8 contacts the smooth inner wall 12 below the outer locking structure of the inner wall of the outer cylinder 1 to form a pressure sealing structure.

[0036] Further, an inner positioning step 22 is arranged below the sealing ring 8, and an outer positioning step 13 is arranged at the corresponding position of the inner wall of the outer cylinder 1, and the inner positioning step 22 abuts against the outer positioning step 13 to limit the movement of the input valve body 2 to the end. A stop ring 9 is arranged below the inner positioning step 22, and a stop groove 14 is arranged below the outer positioning step 13, and the stop ring 9 can be clamped into the stop groove 14, and the stop ring 9 is a C-shaped structure and is popped open when reaching the stop groove 14 to form the second locking structure, so that the input valve body 2 cannot move any more. There are double locking structures between the input valve body 2 and the outer cylinder 1, which can reliably lock the input valve body 2 after reaching the predetermined position, and do not affect the normal cementing process.

[0037] In the floating collar for cementing provided in the specific embodiments, the input valve body 2, the base 3 and the sealing rod 4 are specifically soluble metal materials that can dissolve in the liquid in the well, which can be aluminum-magnesium alloy and the like. After long-term soaking in the liquid, the soluble metal materials can be dissolved, and subsequent drilling operation is not needed, the post-operation procedure is simplified, and the cementing operation time is saved.

[0038] Before cementing construction, the input valve body 2 is pumped into the inner part of the outer cylinder 1, the inner positioning step 22 abuts against the outer positioning step 13 to fix the position of the input valve body 2, further, the first locking structure is formed by the outer sawtooth-shaped groove 11 and the inner sawtooth-shaped groove 21, the second locking structure is formed by the stop ring 9 and the stop groove 14, and the pressure sealing structure is formed by the sealing ring 8 and the smooth inner wall 12. The sealing rod 4 is pushed by the spring 5 to push the rubber layer 6 into sealing contact with the end opening of the inner passage of the input valve body 2, the liquid pressure pushes the sealing rod 4 to move downward, the rubber layer 6 is separated from the end opening of the inner passage of the input valve body 2 to form a passage, the hydraulic pressure passes through the input valve body 2 and the base 3, and finally flows out through the circulation holes 32, after the pressure is removed, the spring 5 pushes the sealing rod 4 to reset, and the safety of the cementing operation is ensured. After the cementing operation is completed, the input valve body 2, the base 3 and the sealing rod 4 are dissolved, and do not need to be removed, and when the well is drilled again, the drilling time is shortened.

[0039] In addition to the float collar for cementing described above, the specific embodiments of the present application also provide a drilling device comprising the float collar for cementing described above, and the structures of other parts of the drilling device refer to the prior art, which will not be described herein.

[0040] The float collar for cementing and the drilling device provided by the present application are described in detail above. The principles and embodiments of the present application are described by applying specific examples, and the above description of the examples is only used to help understand the method of the present application and its core idea. It should be pointed out that, for those skilled in the art, some improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A float collar for cementing a well, characterized in that The application relates to a well cementing device, which comprises a coaxially-arranged outer cylinder (1) and a drop-in valve body (2), the outer cylinder (1) is fixedly connected with and conducts a sleeve, the drop-in valve body (2) is internally provided with an axial through hole, the inner wall of the outer cylinder (1) is provided with an outer locking structure, the outer wall of the drop-in valve body (2) is provided with an inner locking structure, before well cementing construction, the drop-in valve body (2) is pumped into the inner part of the outer cylinder (1), the inner locking structure and the outer locking structure are in contact and are locked with each other, so that the relative position of the drop-in valve body (2) and the outer cylinder (1) is fixed, and a one-way mechanism for limiting the flow of liquid in a well is arranged in the drop-in valve body (2). The outer cylinder (1) is directly installed on the sleeve, the inner diameter of the outer cylinder (1) is consistent with the sleeve, so that the outer cylinder (1) and the sleeve are used as a drill string in well drilling work. The outer locking structure and the inner locking structure are specifically outer and inner sawtooth grooves (11) and (21) which are arranged in sequence along the axial direction, a sealing ring (8) is arranged below the inner locking structure, and the sealing ring (8) is in contact with a smooth inner wall (12) below the outer locking structure to form a pressure sealing structure.

2. The float collar for use in well cementation according to claim 1, characterized in that, The one-way mechanism comprises coaxially-arranged a base (3) and a sealing rod (4), the first end of the base (3) is connected with the end of the drop-in valve body (2) and conducts the drop-in valve body (2), the end bottom plate of the base (3) is provided with a circulating hole (32) for the flow of liquid in a well, the sealing rod (4) is installed in the inner part of the base (3), the first end of the sealing rod (4) is provided with a sealing head, the outer periphery of the sealing rod (4) is sleeved with a spring (5), the two ends of the spring (5) are respectively in abutment with the sealing head and the base (3), the spring (5) pushes the sealing head to tightly seal the end opening of the through hole in the drop-in valve body (2), and the liquid in the well pushes the sealing head to move away from the end opening of the through hole in the drop-in valve body (2) during well cementing work.

3. The float collar for use in well cementation according to claim 2, characterized in that, The first end of the sealing head is provided with a conical surface, the sealing head is covered with a rubber layer (6), and the rubber layer (6) can cooperate with the conical surface at the end opening of the through hole in the drop-in valve body (2).

4. The float collar for use in well cementation according to claim 3, characterized in that, A guide cylinder (31) is arranged in the middle of the end bottom plate of the base (3), the sealing rod (4) passes through the guide cylinder (31), the sealing rod (4) and the guide cylinder (31) are connected through a pin (7) before well cementing construction, and the liquid in the well pushes the sealing rod (4) to move relative to the guide cylinder (31) to cut the pin (7) during well cementing work.

5. The float collar for use in well cementation according to claim 4, characterized in that, The circulating hole (32) is specifically a waist-shaped hole, four waist-shaped holes are arranged around the guide cylinder (31), and the sum of the areas of the circulating holes (32) is greater than the area of the end opening of the through hole in the drop-in valve body (2).

6. The float collar for use in well cementation according to claim 2, characterized by An inner positioning step (22) is arranged below the sealing ring (8), an outer positioning step (13) is arranged at the corresponding position of the inner wall of the outer cylinder (1), and the inner positioning step (22) is in abutment with the outer positioning step (13) to limit the movement of the drop-in valve body (2) to the end.

7. The float collar for use in well cementation according to claim 6, characterized in that, The inner positioning step (22) is provided below with a retreat-stop ring (9), and the outer positioning step (13) is provided below with a retreat-stop groove (14), and the retreat-stop ring (9) can be clamped into the retreat-stop groove (14).

8. The float collar for use in well cementation according to any one of claims 2 to 7, characterized in that, The drop-in valve body (2), the base (3) and the sealing rod (4) are specifically soluble metal materials which can be dissolved in liquid in a well.

9. A drilling apparatus comprising a casing and a float collar for cementing connected to the casing, characterized in that The float collar for well cementation is specifically the float collar for well cementation according to any one of claims 1 to 8.

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