Drill rod dynamic operation sealing device and construction method thereof

Abstract

The invention relates to the technical field of oil exploitation, and discloses a drill rod dynamic operation sealing device which comprises a sealing rubber core, the sealing rubber core comprises a lantern ring on the upper portion and a sleeve integrally connected to the lower end face of the lantern ring, an inner hole is formed in the middle of the sealing rubber core, and the sealing rubber core is arranged on a drill rod in a sleeving mode through the inner hole; and an inner skeleton is melted into the sealing rubber core and is made of a high-strength alloy spring steel material. The sealing rubber core can effectively prevent well fluid from overflowing from an annular space of a drilling tool and a casing pipe, unsafe factors caused by the well fluid to well repair operation are eliminated, the sealing rubber core has the pressure bearing capacity of 8 MPa or above, the HXNBR rubber core is used, and the dynamic sealing range is phi 71 mm-phi 108 mm; and oil-water overflow at a well mouth can be fully sealed in the drill rod tripping operation.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum exploitation, in particular to a drill rod dynamic operation sealing device and a construction method thereof. Background Art

[0002] In the process of oil production, horizontal wellbore management, accident well salvage, secondary well sealing and other difficult and complex overhaul operations, 7 / 8″ drill pipes are used very frequently. Among the more than 60,000 production wells in Changqing Oilfield, more than 2,000 wells are overhauled each year. 7 / 8″ drill pipe outer diameter range is φ73mm~φ105mm, such as Figure 1 As shown in the figure, it is extremely difficult to seal during the dynamic operation of raising and lowering the pipe string. In the national downhole operation system, there is no corresponding sealing device. During the dynamic operation, the wellhead annulus is always open, the oil and water overflow cannot be controlled, and the oil and water carried by the drill pipe fall over an area of ​​200m 2 The labor intensity of clean production is huge. The construction environment at the wellhead is harsh, and the operators have difficulty in moving, which seriously restricts work efficiency. The accompanying safety hazards such as falling risks and mechanical injuries run through the entire construction process.

[0003] Based on this, we designed a drill pipe dynamic operation sealing device and its construction method. Summary of the invention

[0004] 1. Technical issues to be solved

[0005] In view of the deficiencies in the prior art, the present invention provides a drill pipe dynamic operation sealing device and a construction method thereof, which can effectively prevent well fluid from overflowing from the annular space between the drill tool and the casing, eliminate the unsafe factors caused by the well fluid to the well repair operation, and is suitable for various processes in which there is pressure in the well and the drill tool needs to move up and down and rotate.

[0006] (II) Technical solution

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A dynamic operation sealing device for a drill pipe comprises a sealing rubber core, wherein the sealing rubber core comprises an upper ring and a sleeve integrally connected to the lower end surface of the ring, an inner hole is provided in the middle of the sealing rubber core, and the sealing rubber core is sleeved on the drill pipe through the inner hole; an inner skeleton is melted into the interior of the sealing rubber core, and the inner skeleton is made of high-strength alloy spring steel.

[0009] Preferably, the sealing rubber core uses HXNBR hydrogenated hydroxynitrile rubber rubber core.

[0010] Preferably, the lower end surface of the sealant core is further provided with a trapezoidal ring, the diameter of which is larger than the outer diameter of the sleeve, and is used to be embedded in the sealing groove of the blowout preventer to achieve a sealing effect.

[0011] Preferably, the inner hole has an upper diameter of 120 mm, a middle diameter of 70 mm, and a lower diameter of 112 mm.

[0012] Preferably, the dynamic sealing range of the sealing rubber core is: φ71mm~φ108mm.

[0013] Preferably, the endoskeleton comprises a metal flange, a fixing ring 1, a fixing ring 2 and a U-shaped spring steel, a through hole is provided in the middle of the metal flange, and an extension portion is provided at the through hole of the metal flange, a fixing ring 1 and a fixing ring 2 are provided on the outside of the extension portion, a plurality of U-shaped spring steels are fixedly connected to the lower end surface of the metal flange, and the plurality of U-shaped spring steels are distributed in an annular array on the outside of the through hole, and the upper end of the U-shaped spring steel passes through the fixing ring 2 and the fixing ring 1 in sequence and is fixedly connected to the lower end of the metal flange;

[0014] The function of the metal flange is to increase the structural stability of the sealant core and prevent the sealant core from wrinkling when the drill pipe is raised or lowered.

[0015] The U-shaped spring steel makes the sealant core more elastic, so that it can fit more closely to the outer wall of the drill pipe.

[0016] A construction method for a drill pipe dynamic operation sealing device comprises the following steps:

[0017] Step 1: Use the hydraulic disassembly tool to install the sealant core sleeve to 2 7 On the short drill rod of / 8″ drill rod, put on the sealant core gland at the same time;

[0018] Step 2: Install the short drill pipe onto the imported drill pipe so that the sealant core is embedded in the blowout preventer (applicable to "150", "250" and "350" ram blowout preventers), and connect the sealant core gland and the blowout preventer with bolts to fix the sealant core;

[0019] Step 3: Start the oil production equipment and drive the drill pipe to go up and down.

[0020] (III) Beneficial effects

[0021] Compared with the prior art, the present invention provides a drill pipe dynamic operation sealing device and a construction method thereof, which have the following beneficial effects:

[0022] 1. The sealant core of the present invention can effectively prevent well fluid from overflowing from the annular space of the drilling tool and casing, eliminate the unsafe factors caused by the well fluid to the well repair operation, have a pressure bearing capacity of more than 8MPa, use HXNBR hydrogenated hydroxy nitrile rubber core, dynamic sealing range: φ71mm~φ108mm; during the operation of pulling and lowering the drill pipe, the oil and water overflow at the wellhead can be fully sealed.

[0023] 2. No change in wellhead operating height: 2 7 / 8″drill pipe annular self-sealing well sealer is embedded in the inner cavity of the blowout preventer, which does not change the height of the original operating equipment, the wellhead operating height, or the working intensity of the wellhead operators, and can meet the construction requirements of grinding and milling operations, casing milling operations, and well washing operations.

[0024] 3. Sealant core increases the internal skeleton: 2 7 / 8″ The outer diameter of the drill pipe body is φ73mm, and the outer diameter of the coupling is φ105mm. The sealing diameter range is large, which is easy to cause the sealant core to deform and fail. By melting the inner skeleton of high-strength alloy spring steel into the sealant core, the stability and sealing of the sealing component are effectively improved. It is a solution to 2 7 / Key technology for dynamic sealing of 8″ drill pipe.

[0025] 4. By adding composite material annular sealing devices to the cavity of the "150", "250" and "350" ram blowout preventers, 2 7 / 8″ drill pipe is cleanly taken out of the well, and the wear resistance of the sealant core of the well sealer reaches more than 500 drill pipes. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 For 2 7 / Schematic diagram of the structure of 8″ drill pipe;

[0027] Figure 2 It is a structural schematic diagram of the present invention;

[0028] Figure 3 is a schematic diagram of the structure of the endoskeleton in the present invention;

[0029] Figure 4 is a cross-sectional view of the sealing rubber core of the present invention;

[0030] Figure 5 It is a sectional stereoscopic diagram of the sealing rubber core of the present invention;

[0031] Figure 6 is a front view of the endoskeleton of the present invention;

[0032] Figure 7 It is a cross-sectional view of the connection between the sealing rubber core and the inner skeleton of the present invention;

[0033] Figure 8 It is a schematic diagram of the structure of the present invention when it is in use.

[0034] In the figure: 1. Sealant core; 11. Ring; 12. Sleeve; 13. Trapezoidal ring; 14. Inner hole; 2. Inner skeleton; 21. Metal flange; 22. Fixing ring 1; 23. Fixing ring 2; 24. U-shaped spring steel. DETAILED DESCRIPTION

[0035] Figure 1 For 2 7 / 8" drill rod structural diagram, the present invention is mainly aimed at 2 7 The outer wall of the drill pipe is sealed during the tripping operation to prevent the oil and water from overflowing from the gap of the drill pipe during the tripping operation. The technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiment of the present invention.

[0036] Example: See Figure 2-8 A dynamic operation sealing device for a drill pipe comprises a sealing rubber core 1, wherein the sealing rubber core 1 comprises an upper sleeve 11 and a sleeve 12 integrally connected to the lower end surface of the sleeve 11, an inner hole 14 is arranged in the middle of the sealing rubber core 1, and the sealing rubber core 1 is sleeved on the drill pipe through the inner hole 14; an inner skeleton 2 is melted into the interior of the sealing rubber core 1, and the inner skeleton 2 is made of alloy spring steel.

[0037] Due to 2 7 The outer diameter of the / 8″ drill pipe body is φ73mm, the outer diameter of the coupling is φ105mm, and the sealing diameter range is large, which easily causes the sealant core 1 to deform and fail. By melting the inner skeleton 2 made of high-strength alloy spring steel into the sealant core 1, the stability and sealing of the sealing component are effectively improved.

[0038] In this embodiment, the sealing rubber core 1 uses HXNBR hydrogenated hydroxynitrile rubber rubber core.

[0039] In this embodiment, a trapezoidal ring 13 is further provided on the lower end surface of the sealant core 1. The diameter of the trapezoidal ring 13 is larger than the outer diameter of the sleeve 12 and is used to be embedded in the sealing groove of the blowout preventer to achieve a sealing effect.

[0040] In this embodiment, the diameter of the inner hole 14 at the upper end is 120 mm, the diameter of the middle part is 70 mm, and the diameter of the lower end is 112 mm.

[0041] In this embodiment, the dynamic sealing range of the sealing rubber core 1 is φ71mm~φ108mm, and the pressure bearing capacity is above 8MPa.

[0042] In this embodiment, the endoskeleton 2 includes a metal flange 21, a fixing ring 1 22, a fixing ring 23 and a U-shaped spring steel 24. A through hole is provided in the middle of the metal flange 21, and an extension portion is provided at the through hole of the metal flange 21, and a fixing ring 1 22 and a fixing ring 23 are provided on the outside of the extension portion. A plurality of U-shaped spring steels 24 are fixedly connected to the lower end surface of the metal flange 21, and the plurality of U-shaped spring steels 24 are distributed in a circular array on the outside of the through hole, and the upper end of the U-shaped spring steel 24 passes through the fixing ring 23 and the fixing ring 1 22 in sequence and is fixedly connected to the lower end of the metal flange 21;

[0043] The function of the metal flange 21 is to increase the structural stability of the sealant core 1 and prevent the sealant core 1 from wrinkling when the drill pipe is raised or lowered.

[0044] The U-shaped spring steel 24 makes the sealant core 1 more elastic, so that it can fit more closely to the outer wall of the drill pipe and use the change in the diameter of the drill pipe to achieve a better sealing effect and prevent oil and water overflow.

[0045] A construction method for a drill pipe dynamic operation sealing device comprises the following steps:

[0046] Step 1: Use the hydraulic disassembly tool to install the sealant core 1 onto 2 7 On the short drill rod of / 8″ drill rod, put on the sealant core 1 gland at the same time;

[0047] Step 2: Install the short drill pipe onto the imported drill pipe so that the sealant core 1 is embedded in the blowout preventer, which is a "150", "250" or "350" gate blowout preventer, and fix the sealant core 1 gland and the blowout preventer with bolts to fix the sealant core 1;

[0048] By embedding it into the inner cavity of the blowout preventer, the height of the original operating equipment, the operating height of the wellhead, and the working intensity of the wellhead operators are not changed, and the construction requirements of grinding and milling operations, casing milling operations, and well washing operations can be met.

[0049] By adding composite material annular sealing devices in the cavity of the "150", "250" and "350" gate blowout preventers, 2 7 / 8″ drill pipe is cleaned out of the well, and the wear resistance of the sealant core 1 of the well sealer reaches more than 500 drill pipes.

[0050] Step 3: Start the oil production equipment and drive the drill pipe to go up and down.

[0051] Scientific and technological applications of the invention:

[0052] Project Name: 2 7 / 8″Drill Pipe Dynamic Operation Sealing Device

[0053] Application unit: Downhole Operation Team of the Second Oil Production Plant of Changqing Oilfield Branch

[0054] Application results start and end time: September 2022-August 2023

[0055] Application and economic benefits:

[0056] So far, the results have been successfully applied in 79 overhaul sites, including Huan 1*8-95 Well, Xinzhong 8* Well, Hua C*-6 Well, Chengye* Well, etc. After the device was put into use, the construction conditions under the wellhead oil sludge and sewage environment were completely changed, effectively reducing labor injuries. Under the condition of closed wellhead annulus, oil and water do not come out of the well, which greatly improves work efficiency. The construction period of 79 wells was reduced by 395 days in total; the total amount of polymer membrane used was reduced by 11,400m 2 , reducing the amount of sludge produced by 38,000 kg, increasing crude oil production by 612.3 tons, with a total economic benefit of 9.02 million yuan, achieving both economic and environmental benefits.

[0057] Calculation basis:

[0058] Crude oil market price: 4,500 yuan / ton

[0059] Production of a single well at the second oil production plant: 1.55 tons

[0060] Polymer membrane cost: 130 yuan / m 2

[0061] Sludge disposal fee: 1,200 yuan / ton

[0062] Construction cost of oil well overhaul operation: 12,000 yuan / day.

Claims

1. A drill pipe dynamic operation sealing device, comprising a sealing rubber core (1), characterized in that: The sealing rubber core (1) comprises an upper sleeve (11) and a sleeve (12) integrally connected to the lower end surface of the sleeve (11); an inner hole (14) is provided in the middle of the sealing rubber core (1) and is sleeved on the drill rod through the inner hole (14); an inner skeleton (2) is melted into the interior of the sealing rubber core (1), and the inner skeleton (2) is made of alloy spring steel.

2. A drill pipe dynamic operation sealing device according to claim 1, characterized in that: The sealing rubber core (1) uses HXNBR hydrogenated hydroxynitrile rubber rubber core.

3. A drill pipe dynamic operation sealing device according to claim 1, characterized in that: The lower end surface of the sealing rubber core (1) is also provided with a trapezoidal ring (13), and the diameter of the trapezoidal ring (13) is greater than the outer diameter of the sleeve (12).

4. A drill pipe dynamic operation sealing device according to claim 1, characterized in that: The inner hole (14) has an upper diameter of φ120 mm, a middle diameter of φ70 mm, and a lower diameter of φ112 mm.

5. A drill pipe dynamic operation sealing device according to claim 4, characterized in that: The dynamic sealing range of the sealing rubber core (1) is φ71mm~φ108mm.

6. A drill pipe dynamic operation sealing device according to claim 5, characterized in that: The internal skeleton (2) comprises a metal flange (21), a fixing ring 1 (22), a fixing ring 2 (23) and a U-shaped spring steel (24); a through hole is provided in the middle of the metal flange (21), and an extension portion is provided at the through hole of the metal flange (21); a fixing ring 1 (22) and a fixing ring 2 (23) are provided on the outer side of the extension portion; a plurality of U-shaped spring steels (24) are fixedly connected to the lower end surface of the metal flange (21), and the plurality of U-shaped spring steels (24) are distributed in a circular array on the outer side of the through hole; the upper end of the U-shaped spring steel (24) passes through the fixing ring 2 (23) and the fixing ring 1 (22) in sequence and is fixedly connected to the lower end of the metal flange (21).

7. A construction method for a drill pipe dynamic operation sealing device according to any one of claims 1 to 6, characterized in that: The steps include: Step 1: Use the hydraulic disassembly tool to put the sealant core (1) onto 2 7 On the short drill rod of / 8″ drill rod, put the sealing rubber core (1) gland at the same time; Step 2: Install the short drill pipe onto the imported drill pipe so that the sealant core (1) is embedded in the blowout preventer, and the sealant core (1) gland and the blowout preventer are fixedly connected by bolts, thereby fixing the sealant core (1); Step 3: Start the oil production equipment and drive the drill pipe to go up and down.

8. The construction method of a drill pipe dynamic operation sealing device according to claim 7, characterized in that: The sealing rubber core (1) is suitable for "150 type", "250 type" and "350 type" gate blowout preventers.

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