Low-pressure well follow-up kelly bar sealing device

Abstract

The utility model discloses a follow-up kelly bar sealing device for a low-pressure well, which comprises a double-ram blowout preventer fixed on a wellhead four-way joint, a cylindrical base is fixed above the double-ram blowout preventer, and a rotatable sealing connecting pipe is arranged in an inner cavity of the cylindrical base. The upper end of the sealing connecting pipe extends out of an upper end opening of the cylindrical base and is connected with a sealing cylinder in a screwed mode, a piston is arranged on the lower portion of an inner cavity of the sealing cylinder, an inner hexagonal rubber core extruded by the piston is arranged above the piston, and the periphery of the kelly bar is sleeved with the inner hexagonal rubber core in a sealed mode. The kelly bar penetrates through center holes of the piston, the sealing connecting pipe and the double-ram blowout preventer and extends underground, and the top of the inner hexagonal rubber core and the top of the sealing cylinder are covered with half-and-half glands. And an oil inlet hole is formed in the circumference of the lower part of the sealing cylinder, is positioned above a step of the reducing section of the sealing cylinder and is connected with a hydraulic cavity below the piston. The follow-up type kelly bar sealing device for the low-pressure well is reliable in sealing, convenient to construct and good in safety in overhaul, and meanwhile has high economical efficiency and practicability.

Description

Technical Field

[0001] The utility model relates to a drill pipe rotary sealing device, in particular to a low-pressure well follow-up type kelly drill pipe sealing device, belonging to the technical field of drilling equipment. Background Art

[0002] Rotary drilling and milling are important processes in the overhaul of oil and water wells. At present, during the overhaul of oil and water wells, when there is pressure at the wellhead, a gate blowout preventer is installed to prevent blowout, and a rotary blowout preventer is used to seal the square drill pipe to prevent blowout and pollution. However, the rotary blowout preventer has a complex structure, and the installation and replacement of the rubber core are very troublesome. It is basically not used on site, and in most cases it is not configured due to its high price.

[0003] When the wellhead is under pressure and needs to be overhauled, well killing or pressure relief is generally used, which leads to long construction time and high cost. Due to increasingly stringent safety and environmental protection requirements, pressure-carrying operations are required. Pressure-carrying operations require the configuration of a rotary blowout preventer with a sealed square drill pipe, but the rotary blowout preventer has a precise structure, and its installation and operation do not meet the requirements of the site. It is expensive and is rarely used in domestic oil fields. In addition, for wells with low wellhead pressure, the use of expensive rotary blowout preventers has a low cost-effectiveness and does not meet the requirements of economic and efficient development of oil fields. The existing process needs to be improved. Utility Model Content

[0004] The purpose of this section is to summarize some aspects of the embodiments of the utility model and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and utility model name of this application to avoid blurring the purpose of this section, specification abstract and utility model name, and such simplifications or omissions cannot be used to limit the scope of the utility model.

[0005] In view of the above problems and / or the problems existing in the prior art, the present utility model is proposed.

[0006] The purpose of the utility model is to overcome the problems in the prior art that the use of a rotary blowout preventer is expensive and the installation and replacement of a rubber core is inconvenient, and to provide a low-pressure well follow-up type kelly drill pipe sealing device, which has reliable sealing during overhaul, convenient construction, good safety, and high economy and practicality.

[0007] In order to solve the above technical problems, the utility model provides a low-pressure well follow-up square drill pipe sealing device, including a double-gate blowout preventer fixed on a wellhead four-way, a cylindrical base is fixed above the double-gate blowout preventer, the inner cavity of the cylindrical base is provided with a rotatable sealing connecting pipe, the upper end of the sealing connecting pipe extends from the upper port of the cylindrical base and is screwed with a sealing cylinder, a piston is provided at the lower part of the inner cavity of the sealing cylinder, an inner hexagonal rubber core squeezed by the piston is provided above the piston, the inner hexagonal rubber core sealing sleeve is fitted on the outer periphery of the square drill pipe, the square drill pipe extends downward through the central hole of the piston, the sealing connecting pipe and the double-gate blowout preventer, and the top of the inner hexagonal rubber core and the sealing cylinder are covered with a half-type pressure cap.

[0008] Furthermore, a sealing tube reduced diameter section is provided at the lower part of the sealing tube, and the upper end male thread of the sealing connecting pipe is screwed with the lower end female thread of the sealing tube reduced diameter section.

[0009] Furthermore, a piston tail tube with a reduced diameter is provided at the lower end of the piston, and the piston tail tube is inserted into the central hole of the reduced diameter section of the sealing tube.

[0010] Furthermore, an oil inlet hole is provided on the lower circumference of the sealing cylinder, and the oil inlet hole is located above the step of the reduced diameter section of the sealing cylinder and is connected to the hydraulic chamber below the piston.

[0011] Furthermore, two sealing tube O-rings are embedded in the upper inner wall of the reduced diameter section of the sealing tube to achieve sealing with the outer wall of the piston tail tube.

[0012] Furthermore, a copper ring is embedded in the middle section of the outer wall of the large end of the piston, and piston sealing rings are respectively embedded above and below the copper ring to achieve sealing with the inner wall of the sealing tube.

[0013] Furthermore, the joints of the half-type glands are provided with grooves and tenons that fit into each other.

[0014] Furthermore, the upper and lower parts of the sealing connecting tube are respectively supported in the cylindrical base by bearings, the inner ring of the bearing is supported on the outer step of the sealing connecting tube, and the outer ring of the bearing is supported on the inner step of the cylindrical base; the upper port of the cylindrical base is fixed with a bearing cover by screws.

[0015] Furthermore, an annular sealing steel gasket is embedded in the lower port of the cylindrical base, and the lower end of the sealing connecting pipe is inserted into the central hole of the annular sealing steel gasket and is sealed with each other.

[0016] Furthermore, two connecting pipe sealing rings are embedded in the inner peripheral wall of the annular sealing steel pad.

[0017] Furthermore, an annular steel gasket groove is provided at the bottom of the annular sealing steel gasket, and the steel gasket groove corresponds to the groove on the upper end face of the flange of the double-gate blowout preventer and a sealing steel ring is embedded in the groove.

[0018] Compared with the prior art, the utility model has achieved the following beneficial effects: 1. It can economically solve the difficulty of preventing blowout at the wellhead of a pressure well under pressure repair, making the repair construction convenient, safe and reliable, and at the same time having high economy and practicality;

[0019] 2. The Kelly sealant core is movable and has reliable sealing, which can solve the problem of rotating seal in low-pressure well overhaul construction;

[0020] 3. The device has a simple structure and no complicated rotating machinery. It solves the problem that the use of rotary blowout preventers is uneconomical and the installation and replacement of rubber cores are inconvenient. It has high economy and practicality.

[0021] 4. Field test operations have proved that the device is reliable and is well received at underground operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. The drawings are only provided for reference and explanation, not for limiting the present utility model. Among them:

[0023] Figure 1 This is a front view of the utility model of a follow-up Kelly drill pipe sealing device for low-pressure wells;

[0024] Figure 2 for Figure 1 Enlarged view of the upper part;

[0025] In the figure: 1. Kelly rod; 2. Half-type gland; 3. Hexagonal rubber core; 4. Sealing cylinder; 4a. Oil inlet hole; 4b. Reduced diameter section of sealing cylinder; 5. Piston; 5a. Piston tail pipe; 6. Sealing connecting pipe; 7. Bearing gland; 8. Bearing; 9. Cylindrical base; 10. Annular sealing steel pad; 11. Sealing steel ring; 12. Double gate blowout preventer. DETAILED DESCRIPTION

[0026] In the following description of the utility model, the terms "upper", "lower", "front", "back", "left", "right", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the utility model and simplifying the description, and do not mean that the device must have a specific direction.

[0027] In order to make the technical means, creative features, objectives and effects of the present invention easier to understand, the present invention is further described below with reference to specific figures. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0029] like Figure 1 , Figure 2 As shown, the utility model of the low-pressure well follow-up kelly drill pipe sealing device comprises a double-gate blowout preventer 12, a sealing cylinder 4, an inner hexagonal rubber core 3, a piston 5, a sealing connecting pipe 6 and a cylindrical base 9. The lower flange of the double-gate blowout preventer 12 is fixed to the wellhead spool by screws, the cylindrical base 9 is fixed above the double-gate blowout preventer 12, and a cylindrical base flange is provided at the bottom of the cylindrical base 9. The cylindrical base flange is fixedly connected to the upper flange of the double-gate blowout preventer 12 by screws.

[0030] An annular sealing steel pad 10 is embedded in the lower end of the cylindrical base 9, and the lower end of the sealing connecting pipe 6 is inserted into the central hole of the annular sealing steel pad 10. Two connecting pipe sealing rings are embedded in the inner circumferential wall of the annular sealing steel pad 10 to achieve sealing with the outer wall of the sealing connecting pipe 6.

[0031] An annular steel gasket groove is provided at the bottom of the annular sealing steel gasket 10 , which corresponds to the groove on the upper end face of the flange of the double-gate blowout preventer 12 and is embedded with a sealing steel ring 11 , so that the bottom of the annular sealing steel gasket 10 and the top flange of the double-gate blowout preventer 12 are sealed.

[0032] The upper and lower parts of the sealing connection pipe 6 are supported in the cylindrical base 9 by bearings 8 respectively, the inner ring of the bearing 8 is supported on the outer step of the sealing connection pipe 6, and the outer ring of the bearing 8 is supported on the inner step of the cylindrical base 9, so that the sealing connection pipe 6 can rotate in the inner cavity of the cylindrical base 9. The upper end of the cylindrical base 9 is covered with a bearing gland 7, and the circumference of the bearing gland 7 is fixed to the upper end of the cylindrical base 9 by a plurality of countersunk screws.

[0033] The upper end of the sealing connecting pipe 6 extends out from the upper port of the cylindrical base 9 and is screwed with a sealing cylinder 4. A piston 5 is provided at the lower part of the inner cavity of the sealing cylinder 4. An inner hexagonal rubber core 3 is provided above the piston 5 to be squeezed by the piston 5. The inner hexagonal rubber core 3 is sealingly sleeved on the outer periphery of the square drill pipe 1. The square drill pipe 1 passes through the central hole of the piston 5, the sealing connecting pipe 6 and the double-gate blowout preventer 12 and extends downhole. The top of the inner hexagonal rubber core 3 and the sealing cylinder 4 are covered with a half-type gland 2. The joint seam of the half-type gland 2 is provided with grooves and tenons that fit together to form a circular gland, which is easy to disassemble and assemble.

[0034] The lower end of the piston 5 is provided with a piston tail tube 5a with a reduced diameter, which is inserted into the central hole of the sealing tube reduced diameter section 4b. Two sealing tube O-rings are embedded in the upper inner wall of the sealing tube reduced diameter section 4b to achieve sealing with the outer wall of the piston tail tube 5a.

[0035] A sealing tube reduced diameter section 4b is provided at the lower part of the sealing tube 4, and the upper end male thread of the sealing connecting pipe 6 is screwed with the lower end female thread of the sealing tube reduced diameter section 4b.

[0036] An oil inlet hole 4a is provided on the lower circumference of the sealing cylinder 4. The oil inlet hole 4a is located above the step of the reduced diameter section 4b of the sealing cylinder and is connected to the hydraulic chamber below the piston 5. A copper ring is embedded in the middle section of the outer wall of the large end of the piston 5. The upper and lower parts of the copper ring are respectively embedded with piston seals to achieve sealing with the inner wall of the sealing cylinder 4. Pressure oil is injected into the lower chamber of the piston 5 through the oil inlet hole 4a to push the piston 5 upward. The piston 5 presses the inner hexagonal rubber core 3 upward, so that the inner hexagonal rubber core 3 is tightly attached to the outer periphery of the square drill rod 1 to ensure sealing. The inner hexagonal rubber core 3, the piston 5, the sealing cylinder 4 and the sealing connecting pipe 6 rotate with the square drill rod 1.

[0037] During operation, first install the double-gate blowout preventer 12 on the wellhead spool, connect the cylindrical base 9 to the upper flange of the double-gate blowout preventer 12, install the sealing connecting pipe 6 and the annular sealing steel pad 10 and the bearing 8 matched therewith, and then screw the upper end of the sealing connecting pipe 6 to the lower end of the reduced diameter section 4b of the sealing tube. After the connection, put the piston 5 into the sealing tube 4, and insert the piston tail pipe 5a below into the central hole of the reduced diameter section 4b of the sealing tube.

[0038] Then on the drilling platform, insert the lower end of the hexagonal rubber core 3 into the kelly drill rod 1 so that it is held on the kelly drill rod 1, and connect the lower end of the kelly drill rod 1 with the upper buckle of the drill rod in the well. After the connection, lower it into the well, wait for the hexagonal rubber core 3 to enter the sealing tube 4 and abut against the piston 5. Cover the upper port of the sealing tube 4 with two pairs of half-type glands 2, press the top of the hexagonal rubber core 3, and fix the half-type glands 2 with studs and nuts.

[0039] When the rotary table is started for drilling, grinding and milling, the pressure is applied, and the hydraulic pressure pushes the piston 5 upward to compress the hexagonal rubber core 3, thereby achieving sealing at two places between the hexagonal rubber core 3 and the square drill rod 1 and the sealing tube 4. When the rotary table drives the square drill rod 1 to rotate, the square drill rod 1 drives the overall sealing device to rotate accordingly.

[0040] When replacing the inner hexagonal rubber core 3, it is only necessary to disassemble the half-type gland 2, lift the square drill rod 1 to bring out the inner hexagonal rubber core 3, replace it with a new rubber core, and repeat the above installation process, which is very quick and convenient.

[0041] The dynamic seal is mainly completed by the whole device, and the gate blowout preventer undertakes the purpose of safe blowout prevention. When drilling and grinding are not carried out, the kelly 1 is pulled out and the upper part of the rotary seal device is removed as a whole, which does not affect the work of the gate blowout preventer.

[0042] The above description is only the preferred feasible embodiment of the utility model, which shows and describes the basic principle, main features and advantages of the utility model, but does not limit the scope of patent protection of the utility model. The technicians in this industry should understand that the utility model is not limited by the above embodiments. In addition to the above embodiments, the utility model can also have other implementation modes without departing from the spirit and scope of the utility model. The utility model will also have various changes and improvements. All technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the utility model. The scope of protection required by the utility model is defined by the attached claims and their equivalents. The technical features not described in the utility model can be achieved by or using existing technologies, which will not be repeated here.

Claims

1. A low-pressure well follow-up kelly sealing device, comprising a double-gate blowout preventer fixed on a wellhead spool, characterized in that: A cylindrical base is fixed above the double-gate blowout preventer, and a rotatable sealing connection pipe is provided in the inner cavity of the cylindrical base. The upper end of the sealing connection pipe extends out of the upper port of the cylindrical base and is screwed with a sealing cylinder. A piston is provided in the lower part of the inner cavity of the sealing cylinder, and an inner hexagonal rubber core squeezed by the piston is provided above the piston. The inner hexagonal rubber core sealing sleeve is fitted on the outer periphery of the square drill rod, and the square drill rod passes through the piston, the sealing connection pipe and the central hole of the double-gate blowout preventer and extends to the underground well. The tops of the inner hexagonal rubber core and the sealing cylinder are covered with half-type glands.

2. The low-pressure well follow-up kelly pipe sealing device according to claim 1 is characterized in that: A sealing tube reduced diameter section is provided at the lower part of the sealing tube, and the upper end male thread of the sealing connecting pipe is screwed with the lower end female thread of the sealing tube reduced diameter section.

3. The low-pressure well follow-up kelly pipe sealing device according to claim 2 is characterized in that: The lower end of the piston is provided with a piston tail tube with a reduced diameter, and the piston tail tube is inserted into the central hole of the reduced diameter section of the sealing cylinder.

4. The low-pressure well follow-up kelly pipe sealing device according to claim 3 is characterized in that: An oil inlet hole is arranged on the lower circumference of the sealing cylinder. The oil inlet hole is located above the step of the reduced diameter section of the sealing cylinder and is connected to the hydraulic chamber below the piston.

5. The low-pressure well follow-up kelly pipe sealing device according to claim 3 is characterized in that: Two sealing tube O-rings are embedded in the upper inner wall of the reduced diameter section of the sealing tube to achieve sealing with the outer wall of the piston tail tube.

6. The low-pressure well follow-up kelly pipe sealing device according to claim 3 is characterized in that: A copper ring is embedded in the middle section of the outer wall of the large end of the piston, and piston sealing rings are respectively embedded above and below the copper ring to achieve sealing with the inner wall of the sealing cylinder.

7. The low-pressure well follow-up kelly pipe sealing device according to claim 1, characterized in that: The joints of the half-type glands are provided with grooves and tenons which fit in with each other.

8. The low-pressure well follow-up kelly pipe sealing device according to claim 1, characterized in that: The upper and lower parts of the sealing connecting pipe are supported in the cylindrical base through bearings respectively, the inner ring of the bearing is supported on the outer step of the sealing connecting pipe, and the outer ring of the bearing is supported on the inner step of the cylindrical base; the upper port of the cylindrical base is fixed with a bearing cover by screws.

9. The low-pressure well follow-up kelly pipe sealing device according to claim 1, characterized in that: An annular sealing steel pad is embedded in the lower port of the cylindrical base, and the lower end of the sealing connecting pipe is inserted into the central hole of the annular sealing steel pad and sealed with each other.

10. The low-pressure well follow-up kelly pipe sealing device according to claim 9, characterized in that: The inner peripheral wall of the annular sealing steel pad is embedded with two connecting pipe sealing rings.

11. The low-pressure well follow-up kelly pipe sealing device according to claim 9, characterized in that: An annular steel gasket groove is provided at the bottom of the annular sealing steel gasket, and the steel gasket groove corresponds to the groove on the upper end face of the flange of the double-gate blowout preventer and a sealing steel ring is embedded in the groove.

Images