Wellhead single compensation device and using method thereof

Abstract

The invention belongs to the technical field of oil casing pipes, and particularly relates to a wellhead single compensation device which comprises a safety slip and two sets of compensation action mechanisms. Each compensation action mechanism comprises a bearing tension spring, a compensation air cylinder and a mechanical arm which are sequentially connected from bottom to top. The lower ends of the two bearing tension springs are respectively connected with the safety slips; the extension end of the compensation cylinder is connected with the mechanical arm; the upper end of the mechanical arm is connected with an elevator of drilling equipment; during use, an oil casing coupling is hung above an elevator, an oil casing body penetrates through the safety slip, and the two compensation action mechanisms are symmetrically arranged on the two sides of the oil casing body in parallel. The wellhead single compensation device is convenient to operate on site and high in efficiency; and the quality of field operation can be improved, the safety use of the oil casing thread and the reliability of the whole pipe column can be improved, and the use requirements in the oil and gas exploitation field in China can be met.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil casings, and particularly relates to a wellhead single - string compensation device and a using method thereof. Background Art

[0002] With the further development of oil and gas exploration, many oil and gas fields in the western and southwestern regions of China have harsh environments such as high temperature (greater than 140 °C), high pressure (greater than 100 MPa), deep well depth (greater than 5000 m), and high - corrosion media (CO 2 、H 2 S、Cl － ), etc., which pose more stringent requirements on the performance of oil casings. At present, the main connection method for oil casings in ultra - deep high - temperature and high - pressure gas wells is to use special thread joints. The quality of on - site threading directly affects the structural integrity and sealing integrity of the entire pipe string during service. Due to the complex on - site operation environment, during the threading process, factors such as the self - weight of the oil casing, misalignment of the wellhead, swing of the traveling block, and wind force will all affect the accuracy of the male thread of the oil casing entering the thread groove of the coupling, thus causing problems. During on - site operation, if problems such as inaccurate threading, wrong threading, insufficient or excessive threading torque occur, it will cause damage to the threads. At the same time, due to the barrel effect of special thread sealing, leakage and other failures are likely to occur first at the weak points, posing a great threat to the safety of the entire pipe string. Summary of the Invention

[0003] The purpose of the present invention is to provide a wellhead single - string compensation device and a using method thereof, which solve the problem that the oil casing cannot be accurately and efficiently threaded due to factors such as its own weight, misalignment of the wellhead, swing of the traveling block, and wind force.

[0004] The present invention is realized through the following technical solutions:

[0005] The present invention discloses a wellhead single - string compensator device, which includes a safety slip and two sets of compensation mechanisms;

[0006] Each set of compensation mechanism includes a load - bearing spring, a compensation cylinder, and a robotic arm connected in sequence from bottom to top;

[0007] The lower ends of the two load - bearing springs are respectively connected to the safety slip; the extending end of the compensation cylinder is connected to the robotic arm;

[0008] The upper end of the robotic arm is connected to the elevator of the drilling equipment;

[0009] During use, the coupling of the oil casing is suspended above the elevator, the body of the oil casing passes through the safety slip, and the two sets of compensation mechanisms are arranged parallel and symmetrically on both sides of the body of the oil casing.

[0010] Further, the safety slips include a slips housing, and a slips body formed by splicing two slips split teeth is disposed in the slips housing;

[0011] The inner wall of the slips housing is a cone. When the two slips split teeth extend out of the slips housing, the safety slips are in a released state; when the two slips split teeth are in the slips housing, the safety slips are in a clamped state.

[0012] Further, friction blocks are disposed on the inner walls of the slips split teeth.

[0013] Further, two hooks are symmetrically disposed on the outer circular surface of the safety slips, and the lower ends of two load-bearing tension springs are respectively hooked to the hooks.

[0014] Further, the load-bearing tension spring adopts a mechanical spring energy storage structure; the compensating cylinder adopts a unidirectional acting cylinder.

[0015] Further, the compensating cylinder is connected to the load-bearing tension spring, and the length and compensating force of the tension spring are adjusted according to different specifications of the pipe and on-site requirements.

[0016] Further, a hanging ear is prefabricated at the lower end of the compensating cylinder, and the hanging ear is connected to the hook of the load-bearing tension spring.

[0017] Further, two hanging holes are prefabricated on the elevating bowl, and the robotic arm is hooked in the hanging holes of the elevating bowl.

[0018] Further, the extending end of the compensating cylinder is a push rod, and the end of the push rod is hinged to the robotic arm through a connecting rod;

[0019] A U-shaped groove is prefabricated at the end of the push rod, and a hole body is prefabricated at the lower end of the robotic arm, and the connecting rod passes through the hole body and the U-shaped groove.

[0020] The present invention also discloses a using method of the wellhead single joint compensator device, including the following steps:

[0021] S1. Install the wellhead single joint compensator device on the platform elevating bowl, and make the compensating cylinder in an extended state;

[0022] S2. Lift out the oil casing pipe body, and make the oil casing pipe body pass through the safety slips;

[0023] S3. Suspend the oil casing coupling above the wellhead elevating bowl, and lift the elevating bowl;

[0024] S4. Contract the compensating cylinder while the safety slips automatically clamp the oil casing pipe body and lift the oil casing pipe body;

[0025] S5. At this time, the oil casing pipe body is in a zero gravity state under the action of the wellhead single joint compensator device, and the oil casing threads are butted, leaded or made up;

[0026] S6. Relax the compensation cylinder and release the single-stand compensator device at the wellhead.

[0027] S7. Repeat S2 - S6 until the casing and tubing running into the well is completed.

[0028] Compared with the prior art, the present invention has the following beneficial technical effects:

[0029] The present invention discloses a single-stand compensator device at the wellhead, which includes a safety slip and two groups of compensation mechanisms. Each group of compensation mechanisms includes a load-bearing tension spring, a compensation cylinder, and a robotic arm connected in sequence from bottom to top. Among them, the load-bearing tension spring adopts a mechanical spring energy storage structure. By setting a tension spring force with a high safety factor, it mainly realizes that after the compensation cylinder compensates the casing and tubing to a suitable position, the self-weight of the pipe string is balanced with the tensile force of the tension spring, achieving the purpose that the tubing can float up and down in a short distance near the wellhead tongs; the compensation cylinder adopts a single-acting cylinder design. The pneumatic transmission mechanism converts the pressure of compressed air into mechanical energy to drive the mechanism to move linearly back and forth, mainly realizing the operation of clamping and releasing the pipe string by controlling the lifting of the slip; the safety slip is the key component to realize the compensation function, and the safety slip is used to clamp and release the tubing.

[0030] Considering the safety of on-site construction and the moving distance, the compensation cylinder of the entire single-stand compensator device at the wellhead is placed above the load-bearing tension spring, and the safety slip is placed at the lowermost end of the entire single-stand power compensator, making the entire compensator no longer rely on the wellhead collar, having greater flexibility and operating space. The upper end of the compensator is directly connected to the elevating bail of the drilling equipment through the robotic arm, realizing the integration of running in and pulling out the pipe string, simplifying the structure of the single-stand power compensator and making the operation more flexible. The single-stand compensator device at the wellhead of the present invention is convenient for on-site operation and has high efficiency; it can improve the quality of on-site operation, the safe use of the casing and tubing threads, and the reliability of the overall pipe string, and can meet the use needs in the oil and gas exploitation field in China.

[0031] Furthermore, the safety slip includes a slip housing. In the slip housing, there is a slip body composed of two split slip teeth spliced together. The inner wall of the slip housing is a cone, which is convenient for separating the slip body and the slip housing. When the two split slip teeth extend out of the slip housing, the safety slip is in the released state; when the two split slip teeth are inside the slip housing, the safety slip is in the clamped state, so that the clamping and releasing of the tubing by the slip teeth can be controlled through the safety slip.

[0032] Furthermore, friction blocks are provided on the inner walls of the split slip teeth to increase friction and enhance the clamping force.

[0033] The present invention also discloses a method for using a single - root compensator device. After installing the oil - casing pipe body into the single - root compensator device designed, the influence of the self - gravity of the oil - casing can be completely overcome; the single - root compensator for the oil - casing pipe body is convenient for on - site operation and has high efficiency; the single - root compensator for the oil - casing pipe body can meet the use requirements of oil - casings with different sizes on site; the single - root compensator for the oil - casing pipe body can significantly reduce the influence of the on - site environment and can be applicable to various harsh working conditions and construction conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic structural diagram of the wellhead single - root compensator device of the present invention;

[0035] Figure 2 is a schematic structural diagram when the safety slip is in the released state;

[0036] Figure 3 is a schematic structural diagram when the safety slip is in the clamped state;

[0037] Wherein: 1. Oil - casing coupling; 2. Elevator; 3. Manipulator; 4. Compensation cylinder; 5. Load - bearing tension spring; 6. Safety slip; 7. Oil - casing pipe body; 8. Tooth - body connecting piece; 9. Slip housing; 10. Split - tooth body of the slip; 11. Friction block. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] In order to make the objectives, technical solutions and advantages of the present invention clearer, the following further detailed description is provided in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments.

[0039] The components described and shown in the drawings and embodiments of the present invention can be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of the present invention provided in the following drawings is not intended to limit the scope of the present invention claimed, but merely represents a selected embodiment of the present invention. Based on the drawings and embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present invention.

[0040] It should be noted that the term "comprising", "including" or any other variant is intended to cover non - exclusive inclusion, so that a process, element, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to the process, element, method, article or device.

[0041] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0042] A single-rod compensation device for wellhead proposed by the present invention, as Figure 1 shown, mainly consists of a load-bearing spring 5, a compensation cylinder 4 and a safety slip 6. One load-bearing spring 5, one compensation cylinder 4 and one safety slip 6 form a set of compensation mechanism, as Figure 1 shown. In the whole single-rod compensation device for wellhead, the compensation cylinder 4 is placed above the load-bearing spring 5, and the safety slip 6 is placed at the bottom end of the whole single-rod power compensator, so that the whole compensator no longer relies on the coupling of the wellhead, and has greater flexibility and operating space. The load-bearing spring 5 at the upper end of the compensator is directly connected to the elevator 2 of the drilling equipment through the robotic arm 3, realizing the integration with the pipe string being lowered, simplifying the structure of the single-rod power compensator and making the operation more flexible.

[0043] Furthermore, each single-rod compensator structure is composed of 2 sets of compensation mechanisms parallel to the oil casing pipe body 7. Each set of compensation mechanism is formed by hingedly connecting the upper compensation cylinder 4 and the lower load-bearing spring 5, and the length and compensation force can be adjusted according to different specifications of the pipes and on-site requirements.

[0044] When casing running operation for 7-6 / 8in casing (wall thickness 15.11mm) is required on site, among them, the load-bearing spring 5 adopts a mechanical spring energy storage structure. The maximum working load of a single load-bearing spring 5 is 520kg, the load of the pipe string + the lower safety slip 6 is 685kg. Two load-bearing springs 5 are used on the left and right. The self-weight of the pipe string is balanced with the tensile force of the springs, and the calculated safety factor is 1.52, achieving the purpose that the casing can float up and down in a short distance near the wellhead tongs.

[0045] The compensation cylinder 4 adopts a single-acting cylinder design. The pneumatic transmission mechanism converts the pressure of compressed air into mechanical energy to drive the linear reciprocating motion of the mechanism, mainly realizing the operation of clamping and releasing the pipe string by controlling the lifting and lowering of the slips. The load of the pipe string + the lower safety slip 6 + the spring is 700kg. One compensation cylinder 4 is arranged on each of the left and right sides. The maximum working tensile and lowering load of each compensation cylinder 4 is 525kg, and the calculated safety factor is 1.5.

[0046] The safety slip 6 is a key component to realize the compensation function, as Figure 2 shown. The safety slip 6 includes a slip housing 9. In the slip housing 9, there is a slip body formed by splicing two split slip teeth 10. Friction blocks 11 are arranged on the inner walls of the split slip teeth 10 to increase friction and enhance the clamping force.

[0047] Specifically, as Figure 2 shown, tooth connectors 8 are arranged at both ends of one split slip tooth 10, and slots are arranged at both ends of the other split slip tooth 10. The tooth connectors 8 are matched with the slots.

[0048] The inner wall of the slip housing 9 is conical. When the two slip split teeth 10 extend out of the slip housing 9, the safety slip 6 is in a released state; as Figure 3 shown, when the two slip split teeth 10 are in the slip housing 9, the safety slip 6 is in a clamped state. Then, the clamping and releasing of the slip teeth on the tubing can be controlled by the safety slip 6. The string load is 680 kg, and the actual load on the safety slip 6 is about 2500 kg, with a safety factor greater than 3.5.

[0049] As Figure 1 shown, two hooks are symmetrically provided on the outer cylindrical surface of the safety slip 6, and the lower ends of the two load-bearing tension springs 5 are respectively hooked to the hooks.

[0050] The lower end of the compensating cylinder 4 is prefabricated with a hanging ear, and the hanging ear is connected to the hook of the load-bearing tension spring 5.

[0051] Specifically, two hanging holes are prefabricated on the elevating bail 2, and the robotic arm 3 is hooked in the hanging holes of the elevating bail 2. The robotic arm 3 is of a collar structure. Of course, it can also be other structures as long as it can be ensured to be hooked in the elevating bail 2.

[0052] The extending end of the compensating cylinder 4 is a push rod, and the end of the push rod is hinged to the robotic arm 3 through a connecting rod; a U-shaped groove is prefabricated at the end of the push rod, and a hole body is prefabricated at the lower end of the robotic arm 3, and the connecting rod passes through the hole body and the U-shaped groove.

[0053] After arriving at the site, install the single-string dynamic compensator for the oil casing pipe body on the platform elevating bail 2 (to make the cylinder in an extended state); use the elevating bail 2 to lift out the oil casing pipe body 7, so that the oil casing pipe body 7 passes through the single-string dynamic compensator and the safety slip 6, and make the oil casing coupling 1 hang above the wellhead elevating bail 2; lift the elevating bail 2, contract the compensating cylinder 4 while the safety slip 6 automatically clamps the casing and lifts the casing; at this time, the casing is in a zero-gravity state under the action of the single-string dynamic compensator, thread the casing, lead the thread, and make up the thread; relax the compensating cylinder 4, release the single-string dynamic compensator, and repeat the above steps until the oil casing is lowered into the well is completed.

[0054] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the specific implementation manners of the present invention can still be modified or equivalently replaced, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A single-rod compensator device for wellhead, Characterized in that, It includes a safety slip (6) and two sets of compensation mechanisms; Each set of compensation mechanism includes a load-bearing tension spring (5), a compensation cylinder (4) and a robotic arm (3) connected in sequence from bottom to top; The lower ends of the two load-bearing tension springs (5) are respectively connected to the safety slip (6); the extending end of the compensation cylinder (4) is connected to the robotic arm (3); The upper end of the robotic arm (3) is connected to the elevator (2) of the drilling equipment; During use, the oil casing coupling (1) is suspended above the elevator (2), the oil casing body (7) passes through the safety slip (6), and the two sets of compensation mechanisms are arranged parallel and symmetrically on both sides of the oil casing body (7).

2. A single-rod compensator device for wellhead according to claim 1, Characterized in that, The safety slip (6) includes a slip housing (9), and a slip body formed by splicing two slip split teeth (10) is arranged in the slip housing (9); The inner wall of the slip housing (9) is a cone. When the two slip split teeth (10) extend out of the slip housing (9), the safety slip (6) is in a loose state; when the two slip split teeth (10) are in the slip housing (9), the safety slip (6) is in a clamped state.

3. A single-rod compensator device for wellhead according to claim 2, Characterized in that, Friction blocks (11) are arranged on the inner walls of the slip split teeth (10).

4. A single-rod compensator device for wellhead according to claim 1, Characterized in that, Two hooks are symmetrically arranged on the outer circle of the safety slip (6), and the lower ends of the two load-bearing tension springs (5) are respectively hooked to the hooks.

5. A single-rod compensator device for wellhead according to claim 1, Characterized in that, The load-bearing tension spring (5) adopts a mechanical spring energy storage structure; the compensation cylinder (4) adopts a single-acting cylinder.

6. A single-rod compensator device for wellhead according to claim 1, Characterized in that, The compensation cylinder (4) is connected to the load-bearing tension spring (5), and the length and compensation force of the tension spring are adjusted according to different specifications of the pipe and on-site requirements.

7. A single-rod compensator device for wellhead according to claim 1, Characterized in that, A hanging ear is prefabricated at the lower end of the compensation cylinder (4), and the hanging ear is connected to the hook of the load-bearing tension spring (5).

8. A single-rod compensator device for wellhead according to claim 1, Characterized in that, Two hanging holes are prefabricated on the elevator (2), and the robotic arm (3) is hooked in the hanging holes of the elevator (2).

9. A single-rod compensator device for wellhead according to claim 1, Characterized in that, The extending end of the compensation cylinder (4) is a push rod, and the end of the push rod is hinged to the robotic arm (3) through a connecting rod; A U-shaped groove is prefabricated at the end of the push rod, and a hole body is prefabricated at the lower end of the robotic arm (3), and the connecting rod passes through the hole body and the U-shaped groove.

10. The usage method of the single-rod compensator device for wellhead according to any one of claims 1-9, Characterized in that, It includes the following steps: S1. Install the single-rod compensator device for wellhead on the platform elevator (2) and make the compensation cylinder (4) in an extended state; S2. Lift out the casing string (7) so that the casing string (7) passes through the safety slips (6). S3. Suspend the casing coupling (1) above the wellhead elevator (2) and raise the elevator (2). S4. Retract the compensation cylinder (4) while the safety slips (6) automatically clamp the casing string (7) and lift the casing string (7). S5. At this time, the casing string (7) is in a zero-gravity state under the action of the single-string compensator device at the wellhead. Mate, guide or make up the casing threads. S6. Release the compensation cylinder (4) to release the single-string compensator device at the wellhead. S7. Repeat S2 - S6 until the casing running is completed.

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