A high pressure wellhead lock ring release tool and method of use

Abstract

The application discloses a high-pressure wellhead lock ring releasing tool and a use method thereof. The tool comprises a mandrel, a lower end of which is connected with an extended short drill rod; an outer cylinder is arranged on the outer periphery of the mandrel; an upper end of the outer cylinder is fixedly provided with an upper cover, a through hole which is matched with the outer periphery of the mandrel is arranged in the center of the upper cover; the outer cylinder is detachably connected with the mandrel; a plurality of connecting bolts are uniformly arranged on the inner wall of the lower part of the outer cylinder in the circumferential direction; an inner cylinder is provided with an insertion part which is used for being inserted into the lower part of the outer cylinder; a plurality of J-shaped grooves are uniformly arranged on the upper edge of the insertion part in the circumferential direction respectively, and the positions and the number of the plurality of J-shaped grooves are matched with those of the plurality of connecting bolts; a lock ring pressing cylinder is fixedly connected with the lower edge of the inner cylinder; and a plurality of elastic shear pins are arranged on the inner periphery of the lower part of the inner cylinder in the circumferential direction. The tool has the beneficial effect that the lock ring arranged in the annulus between the low-pressure wellhead and the high-pressure wellhead can be pressed down, so that the high-pressure wellhead is separated from the low-pressure wellhead.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas drilling equipment, and particularly relates to a high-pressure wellhead lock ring releasing tool and a use method thereof. BACKGROUND

[0002] The underwater wellhead is a key equipment for deepwater oil and gas exploration and development, and is usually composed of a low-pressure wellhead and a high-pressure wellhead. The lock ring is used for connecting and limiting between the low-pressure wellhead and the high-pressure wellhead, so as to prevent the high-pressure wellhead from accidentally coming out of the low-pressure wellhead during drilling and completion. Figure 4 and Figure 5 As shown in the drawings, the lock ring, also known as a C-shaped ring, is made of metal material and is a circular ring with a notch. The outer periphery of the lock ring is provided with a first taper surface, a water platform step surface, a vertical step surface and a second taper surface connected in sequence from top to bottom. The upper and lower parts of the lock ring are respectively provided with cover plates for limiting the axial position of the lock ring on the high-pressure wellhead. The inner periphery of the low-pressure wellhead at the position corresponding to the lock ring is provided with a clamping groove matched with the water platform step surface and the vertical step surface. In the free state, the water platform step surface and the vertical step surface of the lock ring are embedded in the clamping groove, and the inner periphery of the lock ring is matched with the outer periphery of the high-pressure wellhead to realize the connection of the low-pressure wellhead and the high-pressure wellhead.

[0003] During the permanent well abandonment stage, the hydraulic cutter and the abrasive jet cutting tool are usually used to cut the extension casing welded below the high-pressure wellhead and the low-pressure wellhead. However, since the casing welded below the low-pressure wellhead is usually a large-size casing with a wall thickness of 1 inch or even 2 inches, and the size difference between the high-pressure wellhead and the lower extension casing of the low-pressure wellhead is large, the requirements for the cutting and recycling tool are extremely high.

[0004] Therefore, a high-pressure wellhead lock ring releasing tool capable of pressing down the lock ring to make the lock ring radially contract and separate the high-pressure wellhead from the low-pressure wellhead to realize the separate recycling of the low-pressure wellhead and the high-pressure wellhead becomes the key to solve the problem. SUMMARY

[0005] The present application aims to provide a high-pressure wellhead lock ring releasing tool which can press down the lock ring arranged in the annulus between the low-pressure wellhead and the high-pressure wellhead to make the lock ring radially contract and separate the high-pressure wellhead from the low-pressure wellhead.

[0006] The present application aims to provide a use method of the high-pressure wellhead lock ring releasing tool which can separate the high-pressure wellhead from the low-pressure wellhead.

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical solutions, including the following steps:

[0008] a mandrel, the lower end of which is connected with the long short drill pipe;

[0009] An outer cylinder is sleeved on the outer periphery of the mandrel; an upper end of the outer cylinder is fixedly provided with an upper cover, and a through hole matched with the outer periphery of the mandrel is arranged at the center of the upper cover; the outer cylinder is detachably connected with the mandrel; a plurality of connecting bolts are uniformly arranged on the inner wall of the lower part of the outer cylinder in the circumferential direction;

[0010] An inner cylinder is provided with an insertion part at the upper part thereof, and the outer periphery of the insertion part is matched with the inner periphery of the lower part of the outer cylinder;

[0011] A plurality of J-shaped grooves are uniformly arranged on the upper edge of the insertion part in the circumferential direction, and the number and positions of the J-shaped grooves are matched with those of the connecting bolts; the J-shaped grooves are matched with the connecting bolts to realize the detachable connection between the inner cylinder and the outer cylinder;

[0012] A lock ring pressing cylinder is fixedly connected with the lower edge of the inner cylinder; the lock ring pressing cylinder is inserted into the annular space between the low-pressure wellhead and the high-pressure wellhead, and the lock ring is arranged in the annular space between the low-pressure wellhead and the high-pressure wellhead; the lock ring is radially contracted;

[0013] A plurality of elastic shear pins are uniformly arranged on the inner periphery of the lower part of the inner cylinder in the circumferential direction, and are inserted into the limiting grooves on the outer periphery of the high-pressure wellhead to realize the connection between the inner cylinder and the high-pressure wellhead.

[0014] Preferably, the application further comprises:

[0015] An annular groove is arranged on the outer periphery of the upper part of the mandrel;

[0016] A pair of half circular ring plates are oppositely buckled to form a circular ring structure, and a circular hole is formed at the center of the circular ring structure; the circular hole is in interference fit with the outer periphery of the annular groove;

[0017] A plurality of groups of connecting pins are arranged in the circumferential direction, and each group has two connecting pins; the connecting pins are used to detachably connect the outer cylinder with the mandrel;

[0018] The buckling parts are arranged in an upper-lower staggered manner between the pair of half circular ring plates; and the length of the annular groove is greater than the thickness of the buckling parts.

[0019] Preferably, the application further comprises:

[0020] A limiting flange is arranged on the outer periphery of the mandrel and located directly below the upper cover; the limiting flange is used to abut against the lower end surface of the upper cover.

[0021] Preferably, an inclined surface structure is arranged at the lower end of the lock ring pressing cylinder.

[0022] Preferably, the upper end of the J-shaped groove is a chamfered structure and has a guiding effect.

[0023] The application relates to a method for using a high-pressure wellhead lock ring releasing tool, and the high-pressure wellhead lock ring releasing tool comprises the following steps:

[0024] S1, the high-pressure wellhead lock ring releasing tool is lowered, and the high-pressure wellhead lock ring releasing tool is arranged at a high-pressure wellhead;

[0025] S2, the high-pressure wellhead lock ring releasing tool is pressed, the lock ring in the annulus between the high-pressure wellhead and a low-pressure wellhead is compressed, the lock ring is radially contracted, and the high-pressure wellhead is separated from the low-pressure wellhead;

[0026] S3, the high-pressure wellhead lock ring releasing tool is lifted, the elastic shear pin is connected with a limiting groove of the high-pressure wellhead, and it is verified that the lock ring has been completely contracted;

[0027] S4, the mandrel of the high-pressure wellhead lock ring releasing tool is rotated, then the high-pressure wellhead lock ring releasing tool is lifted, the connecting bolt is slid along the J-shaped groove, the outer cylinder is separated from the inner cylinder, the inner cylinder and the lock ring cylinder are left on the high-pressure wellhead under the locking action of the elastic shear pin, and the mandrel, the outer cylinder and the long short drill rod are retracted;

[0028] S5, the high-pressure wellhead is cut and recovered;

[0029] S6, the low-pressure wellhead is cut and recovered;

[0030] S7, after returning to the land, the stretching frame is used to fix the high-pressure wellhead and the inner cylinder respectively, the inner cylinder is lifted to shear the elastic shear pin, and the inner cylinder is separated from the high-pressure wellhead.

[0031] The application has the beneficial effect that the lock ring arranged in the annulus between the low-pressure wellhead and the high-pressure wellhead can be pressed, the lock ring is radially contracted, and the high-pressure wellhead is separated from the low-pressure wellhead. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is a sectional view of the high-pressure wellhead lock ring releasing tool.

[0033] Figure 2 It is a sectional view of the high-pressure wellhead lock ring releasing tool.

[0034] Figure 3 It is a perspective view of the inner cylinder.

[0035] Figure 4 It is a perspective view of the lock ring.

[0036] Figure 5 It is a sectional view of the lock ring. DETAILED DESCRIPTION

[0037] The application will be further described in detail below with reference to the drawings, so that those skilled in the art can implement the application according to the description and the drawings.

[0038] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0039] like Figures 1-5 As shown, a high-pressure wellhead lock ring release tool of the present invention includes:

[0040] Mandrel 1, the lower end of which is connected to the short drill rod 9 with matching length;

[0041] The outer cylinder 4 is sleeved on the outer periphery of the mandrel 1; the upper end of the outer cylinder 4 is fixedly provided with an upper cover 10, and the center of the upper cover 10 is provided with a through hole that is adapted to the outer periphery of the mandrel 1; the outer cylinder 4 and the mandrel 1 are detachably connected; a plurality of connecting bolts 5 are evenly distributed along the circumference on the inner wall of the lower part of the outer cylinder 4.

[0042] The inner cylinder 6 has an insertion part at its upper part for inserting into the lower part of the outer cylinder 4, and the outer periphery of the insertion part is adapted to the inner periphery of the lower part of the outer cylinder 4;

[0043] Multiple J-shaped grooves 11 are evenly distributed along the circumference on the upper edge of the insertion part and are adapted to the position and number of the multiple connecting bolts 5; the multiple J-shaped grooves 11 are used to cooperate with the multiple connecting bolts 5 to realize the detachable connection between the inner cylinder 6 and the outer cylinder 4;

[0044] The upper end of the locking ring cylinder 8 is fixedly connected to the lower edge of the inner cylinder 6; the locking ring cylinder 8 is used to insert into the annulus of the low-pressure wellhead E2 and the high-pressure wellhead E1, and press down the locking ring E3 set in the annulus of the low-pressure wellhead E2 and the high-pressure wellhead E1, so that the locking ring E3 will generate radial contraction.

[0045] Multiple elastic shear pins 7 are evenly distributed along the circumference of the inner cylinder 6 at the lower part of the inner cylinder 6, and are used to insert into the limiting groove on the outer circumference of the high-pressure wellhead E1 to connect the inner cylinder 6 to the high-pressure wellhead E1.

[0046] In another embodiment, it also includes:

[0047] An annular groove is provided on the outer periphery of the upper part of the mandrel 1;

[0048] A pair of semi-circular plates 2 are interlocked to form a circular structure, and a circular hole is formed in the center of the circular structure. The circular hole is interference-fitted with the outer periphery of the annular groove.

[0049] Multiple sets of connecting pins 3, two in each set, are evenly distributed along the circumference to detachably connect the outer cylinder 4 to the spindle 1.

[0050] Among them, there is an interlocking fastening part between the pair of semi-circular ring plates 2; the groove length of the annular groove is greater than the thickness of the fastening part.

[0051] In another embodiment, further comprising:

[0052] A limiting flange 12 is arranged on the outer periphery of the mandrel 1 and directly below the upper cover 10, and is used to abut the lower end surface of the upper cover 10.

[0053] In another embodiment, a bevel structure is arranged at the lower end of the lock ring compression cylinder 8.

[0054] In another embodiment, the upper end of the J-shaped groove 11 is a chamfer structure 13, which has a guiding effect.

[0055] A method for using a high-pressure wellhead lock ring release tool, which applies any of the above high-pressure wellhead lock ring release tools, comprising the following steps:

[0056] S1, lower the high-pressure wellhead lock ring release tool, and seat the high-pressure wellhead lock ring release tool in the high-pressure wellhead E1;

[0057] S2, press down the high-pressure wellhead lock ring release tool, so that the lock ring compression cylinder 8 compresses the lock ring E3 in the annulus between the low-pressure wellhead E2 and the high-pressure wellhead E1. Due to the arrangement of the first tapered surface E3-1 and the notch E3-4, the downward pressure of the lock ring compression cylinder 8 causes the lock ring E3 to shrink radially, and the horizontal stepped surface E3-2 and the vertical stepped surface E3-3 exit the clamping groove of the low-pressure wellhead E2, so that the high-pressure wellhead E1 is separated from the low-pressure wellhead E2;

[0058] S3, raise the high-pressure wellhead lock ring release tool, and confirm that the elastic shear pin 7 is connected with the limiting groove of the high-pressure wellhead E1, and verify that the lock ring E3 has been completely contracted;

[0059] S4, first rotate the mandrel 1 of the high-pressure wellhead lock ring release tool, and then raise it, so that the connecting bolt 5 slides out along the J-shaped groove 11, and the outer cylinder 4 is separated from the inner cylinder 6. The inner cylinder 6 and the lock ring compression cylinder 8 are left on the high-pressure wellhead E1 under the locking action of the elastic shear pin 7, and the mandrel 1, the outer cylinder 4 and the extended short drill pipe 9 are retracted.

[0060] S5, cut and recover the high-pressure wellhead E1;

[0061] S6, cut and recover the low-pressure wellhead E2;

[0062] S7, after returning to land, use the stretching frame to fix the high-pressure wellhead E1 and the inner cylinder 6 respectively, raise the inner cylinder 6 to shear the elastic shear pin 7, and separate the inner cylinder 6 from the high-pressure wellhead E1.

[0063] In summary, the high-pressure wellhead lock ring release tool and the method for using the same can press down the lock ring E3 arranged in the annulus between the low-pressure wellhead E2 and the high-pressure wellhead E1, cause the lock ring E3 to shrink radially, and separate the high-pressure wellhead E1 from the low-pressure wellhead E2.

[0064] While embodiments of the application have been disclosed in connection with the above specification and drawings this description is not intended to limit the scope of the application and many modifications, enhancements, alternatives, and variations will become apparent to those skilled in the art from this disclosure. Accordingly, it is expressly intended that the description should not limit the application as claimed but rather the only limitation placed on the scope of the application be the scope of the claims as set out below and equivalents thereof.

Claims

1. A high-pressure wellhead locking ring release tool, characterized in that, include: The mandrel, the lower end of which is connected to a short drill rod of appropriate length; An outer cylinder is fitted around the outer periphery of the mandrel; a top cover is fixedly provided at the upper end of the outer cylinder, and a through hole adapted to the outer periphery of the mandrel is provided at the center of the top cover; the outer cylinder and the mandrel are detachably connected; a plurality of connecting bolts are evenly distributed along the circumference on the inner wall of the lower part of the outer cylinder. The inner cylinder has an insertion part at its upper part for inserting into the lower part of the outer cylinder, and the outer periphery of the insertion part is adapted to the inner periphery of the lower part of the outer cylinder; Multiple J-shaped grooves are evenly distributed along the circumference on the upper edge of the insertion part and are adapted to the position and number of the multiple connecting bolts; the multiple J-shaped grooves are used to cooperate with the multiple connecting bolts to realize the detachable connection between the inner cylinder and the outer cylinder; A locking ring cylinder, the upper end of which is fixedly connected to the lower edge of the inner cylinder; the locking ring cylinder is used to insert into the annulus of the low-pressure wellhead and the high-pressure wellhead, and press down the locking ring set in the annulus of the low-pressure wellhead and the high-pressure wellhead, so that the locking ring will generate radial contraction; Multiple elastic shear pins are evenly distributed along the circumference of the inner cylinder at the lower part of the inner cylinder. They are used to insert into the limiting groove on the outer circumference of the high-pressure wellhead to connect the inner cylinder to the high-pressure wellhead.

2. The high-pressure wellhead locking ring release tool according to claim 1, characterized in that, Also includes: An annular groove is provided on the outer periphery of the upper part of the mandrel; A pair of semi-circular ring plates are interlocked to form a ring structure, and a circular hole is formed in the center of the ring structure. The circular hole is interference-fitted with the outer periphery of the annular groove. Multiple sets of connecting pins, two in each set, are evenly distributed along the circumference to detachably connect the outer cylinder to the spindle. The pair of semi-circular ring plates are provided with staggered fastening parts; the length of the annular groove is greater than the thickness of the fastening parts.

3. The high-pressure wellhead locking ring release tool according to claim 2, characterized in that, Also includes: A limiting flange is disposed on the outer periphery of the mandrel and located directly below the upper cover, for abutting against the lower end face of the upper cover.

4. The high-pressure wellhead locking ring release tool according to claim 1, characterized in that: An inclined surface structure is provided at the lower end of the locking ring pressure cylinder.

5. The high-pressure wellhead locking ring release tool according to claim 1, characterized in that: The upper port of the J-shaped groove has a chamfered structure, which serves a guiding function.

6. A method for using a high-pressure wellhead lock ring release tool, employing the high-pressure wellhead lock ring release tool according to any one of claims 1-5, characterized in that... Includes the following steps: S1. Lower the high-pressure wellhead lock ring release tool and place the high-pressure wellhead lock ring release tool at the high-pressure wellhead; S2. Press down the high-pressure wellhead locking ring release tool to compress the locking ring in the annulus between the low-pressure and high-pressure wellheads, causing the locking ring to contract radially and separating the high-pressure and low-pressure wellheads. S3. Use the high-pressure wellhead locking ring release tool to confirm that the elastic shear pin is connected to the limiting groove of the high-pressure wellhead and verify that the locking ring has fully contracted. S4. First, rotate the mandrel of the high-pressure wellhead locking ring release tool, then lift it up so that the connecting bolt slides out along the J-shaped groove, separating the outer cylinder from the inner cylinder. The inner cylinder and the locking ring pressure cylinder remain on the high-pressure wellhead under the locking action of the elastic shear pin. Then, retract the mandrel, outer cylinder, and matching long and short drill pipes. S5. Cut and recover the high-pressure wellhead; S6. Cut and recover the low-pressure wellhead; S7. After returning to land, use the tensioning frame to fix the high-pressure wellhead and inner cylinder respectively, lift the inner cylinder to cut the elastic shear pin, and separate the inner cylinder from the high-pressure wellhead.

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