Device and method for cross-core fishing of coiled tubing

Abstract

The invention relates to a device and method for cross-core fishing of coiled tubing. The device comprises a body, a steel wire rope, a union joint and a sealing mechanism. The upper end of the body is connected with the sealing mechanism, the steel wire rope penetrates through the sealing mechanism and the body, the outer diameter of the body is consistent with that of an oil pipe, the two ends of the steel wire rope are provided with an upper connector and a lower connector respectively, the upper connector is connected with a lifting wire and connected with a crane, and the lower connector is connected with a ball head quick connector and connected with a coiled tubing to be fished. And the union joint is arranged on the body and is connected with a pump injection pipeline. By means of the sealing performance, the tensile strength and the flexibility of the sealing mechanism and the steel wire rope, the problem that environment pollution or well control risks are caused due to the fact that common cross-core fishing cannot achieve sealing circulation is solved, the safety of cross-core fishing of the coiled tubing can be improved, operation is easy, the time efficiency is high, and the cross-core fishing device is suitable for fishing of clamped and buried coiled tubing of different sizes and wide in applicability.

Description

Technical Field

[0001] The present invention relates to the technical field of well repair, and more particularly to a device and method for fishing a coiled tubing through a core. Background Art

[0002] With the exploration and development of the Fuling shale gas field, coiled tubing is increasingly used in the oil test and completion stage. With the continuous deepening of oil and gas field exploration and development, the formation energy gradually decreases. When using coiled tubing for sand flushing or drilling plug construction, gravel or debris may not be returned in time, resulting in the failure of buried coiled tubing. If the coiled tubing and the tools connected to the lower part are stuck in the casing, the coiled tubing can be easily broken from the upper part by forcibly pulling it up and releasing it. Once the coiled tubing is broken from the upper part, due to its particularity, it is very difficult and risky to release and salvage it. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a device and method for salvaging a coiled tubing through a core, which can remove the stuck state of the coiled tubing in the well without damaging the wellbore conditions and the coiled tubing, thereby improving the salvage and unblocking efficiency while meeting the requirements of not polluting the environment and controlling well control risks.

[0004] The technical solution adopted by the present invention to solve its technical problems is: constructing a device for through-hole salvaging continuous oil pipe, comprising a body, a wire rope, a union joint and a sealing mechanism; the upper end of the body is connected to the sealing mechanism, the wire rope passes through the sealing mechanism and the body, the outer diameter of the body is consistent with the outer diameter of the oil pipe, the two ends of the wire rope are respectively provided with an upper joint and a lower joint, the upper joint is used to be connected to a crane, and the lower joint is used to be connected to the continuous oil pipe to be salvaged, the union joint is arranged on the body, and the union joint is connected to the pumping pipeline.

[0005] In the above scheme, the sealing mechanism includes an upper shell, an overflow port, a sealing rubber barrel, a lower shell and a pressure port; the upper shell and the lower shell are connected by threads, a bell mouth is provided at the upper end of the upper shell, an upper pad and a baffle are provided between the bell mouth and the upper shell, the overflow port and the pressure port are arranged on the upper shell, a lower pad and a baffle are provided inside the lower shell, the sealing rubber barrel is fixed between the upper pad and the lower pad, the baffle and the baffle are used to prevent the hydraulic oil from overflowing when pressurizing from the pressure port, the wire rope is inserted from the bell mouth, and the sealing rubber barrel forms a seal with the wire rope under the action of hydraulic loading.

[0006] In the above solution, a sheath is provided on the outside of the sealing rubber barrel.

[0007] In the above solution, a spring is provided between the upper shell and the lower shell.

[0008] In the above solution, the union is connected to the pinball disk to ensure that the union can rotate 360 ​​degrees.

[0009] In the above scheme, the pinball disk includes a loading mechanism and a rotating structure, and the union is connected to the rotating structure.

[0010] In the above scheme, the upper joint and the lower joint both include a fixed head and a fixed lead block, and the outer diameter of the fixed head is smaller than the inner diameter of the body.

[0011] The present invention also provides a method for salvaging a coiled tubing through a core, and the method adopts the device for salvaging a coiled tubing through a core, comprising the following steps:

[0012] S1, well killing: prepare well killing fluid according to the shut-in pressure and formation pressure coefficient, reduce the pressure in the casing and coiled tubing to 0, and cut the coiled tubing;

[0013] S2. Use a workover rig to select a tubing of appropriate size and run it through the tubing until it encounters resistance;

[0014] S3, the through-core fishing coiled tubing device is connected to the through-core fishing coiled tubing, the through-core fishing coiled tubing tool can move up and down with the traveling block of the workover rig, the wire rope is passed through the through-core fishing coiled tubing, the lower end of the wire rope is connected to the ball head quick connector, the ball head quick connector is connected to the coiled tubing, the body is connected to the wellhead tubing, the upper joint is connected to the lifting wire and then connected to the crane, and the union is connected to the pumping pipeline;

[0015] S4. Dynamic sealing of the wire rope is achieved by applying pressure to the sealing mechanism, so as to ensure that the device for salvaging the coiled tubing through the core can move up and down with the traveling pulley of the workover rig;

[0016] S5. Circulate working fluid from the union joint through pumping equipment to carry debris and other debris from the blocked part of the tubing, i.e., where the coiled tubing is stuck, out of the ground through positive circulation;

[0017] S6. Keep the cycle, lower the tubing deeper by the traveling block to continuously remove the obstruction outside the coiled tubing. When the tubing is lowered to the rotary table, the connection between the tubing and the through-core fishing device needs to be disconnected. First, disconnect the tubing male thread from the wellhead tubing, then disconnect the ball head quick connector, pass the wire rope through another through-core tubing, then restore the connection of the ball head quick connector and the tubing male thread to the through-core tubing, thereby achieving continuous washing and removing the obstruction outside the coiled tubing.

[0018] S7. After the coiled tubing is unblocked, remove the through-core fishing device for the coiled tubing, and use a through-core rod with the same outer diameter as the coiled tubing to connect the coiled tubing. If the bottom tool of the coiled tubing can pass through the through-core tubing, place the tubing on the turntable of the workover rig, use the coiled tubing equipment to rewind the coiled tubing in the well, and then pull out the tubing; otherwise, reverse through-core fishing to pull out the tubing in the well, and then use the coiled tubing equipment to rewind the coiled tubing in the well.

[0019] The device and method for fishing coiled tubing through the core of the present invention have the following beneficial effects:

[0020] 1. When the coiled tubing is stuck and cannot be salvaged using conventional methods, a workover rig is used for through-hole salvage. The through-hole salvage device is connected to the tubing with a crane, and the steel wire rope is passed through the tubing and connected to the top of the coiled tubing to be salvaged. The tubing is docked to achieve through-hole lifting, maintaining the integrity of the coiled tubing and avoiding underground complexity and engineering risks. The present invention solves the problem that traditional salvage cannot ensure the integrity of the coiled tubing and solves the problem of underground stuckness, avoids environmental pollution, and the well control risk is controllable, and the salvage and unblocking efficiency is high.

[0021] 2. The device of the present invention is used on a workover rig platform and is pressurized by a hand pump to seal the entire space composed of the wire rope, the body and the oil pipe. The function of continuous circulation and casing washing is realized from the union joint. The circulation channel is for oil pipe injection and casing return. It does not produce any adverse effects on the well and does not increase the risk of continuous oil pipe breaking. Even if the salvage is not successful, it does not interfere with the state in the well.

[0022] 3. The present invention does not need to lower other tools. By continuously inserting the through-core fishing coiled tubing device on the ground, the through-core fishing coiled tubing is pulled out, and the through-core fishing tubing string is continuously extended, thereby removing the stuck coiled tubing in the well. The construction process is simple, the construction success rate is high, and the safety is good.

[0023] 4. The present invention can be applied to the operation of salvaging a coiled tubing that is buried and extends to the wellhead. Compared with other well repair measures, the number of tools used is small, and the construction operations are concentrated on the ground. It has the advantages of not damaging the coiled tubing, not damaging the wellbore environment, and not affecting subsequent construction measures. It has a high construction success rate and good safety, and has good economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0025] Figure 1 It is a structural schematic diagram of a device for salvaging a coiled tubing through a core according to the present invention;

[0026] Figure 2 It is a cross-sectional view of a device for fishing a coiled tubing through a core according to the present invention;

[0027] Figure 3 It is a schematic diagram of another angle of the device for salvaging coiled tubing according to the present invention. DETAILED DESCRIPTION

[0028] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0029] like Figure 1-3 As shown, the device for fishing coiled tubing through the core of the present invention comprises a body 1, a steel wire rope 2, a union 3 and a sealing mechanism 4.

[0030] The upper end of the body 1 is connected to the sealing mechanism 4, and the wire rope 2 passes through the sealing mechanism 4 and the body 1. The outer diameter of the body 1 is consistent with the outer diameter of the oil pipe. The two ends of the wire rope 2 are respectively provided with an upper joint 2032 and a lower joint 2031. The upper joint 2032 is used to connect to the crane, and the lower joint 2031 is used to connect to the coiled oil pipe to be salvaged. The union 3 is arranged on the body 1, and the union 3 is connected to the pumping pipeline.

[0031] The sealing mechanism 4 includes an upper shell 402, an overflow port 405, a sealing glue barrel 408, a lower shell 410 and a pressing port 412. The upper shell 402 is connected to the lower shell 410 by threads, and the body 1 is connected to the lower shell 410 by connecting threads 102.

[0032] A bell mouth 401 is provided at the upper end of the upper shell 402. An upper pad 403 and a flow block 404 are provided between the bell mouth 401 and the upper shell 402, and an overflow port 405 and a pressure port 412 are provided on the upper shell 402. A lower pad 409 and a flow block 411 are provided inside the lower shell 410, and a sealing rubber barrel 408 is fixed between the upper pad 403 and the lower pad 409. The flow block 404 and the flow block 411 are used to prevent the hydraulic oil from overflowing when pressurizing from the pressure port 412. The steel wire rope 2 is inserted from the bell mouth 401, and the sealing rubber barrel 408 forms a seal with the steel wire rope 2 under the action of hydraulic loading.

[0033] The steel wire rope 2 and the sealing mechanism 4 press and squeeze the sealing rubber barrel 408 through the pressurizing port 412, reducing the gap between the sealing rubber barrel 408 and the sealing steel wire rope 2, thereby isolating the pressure in the body 1 and the connected oil pipe. The sealing steel wire rope 2 can pass through the body 1 when the hand pressure pump is not used to pressurize the pressurizing port 412. After the pressurization, a certain force needs to be applied to make the body 1 and the through-core steel wire rope 2 relatively displaced.

[0034] Preferably, a protective sleeve 407 is provided on the outside of the sealant barrel 408. After the sealant barrel 40 is worn, the upper and lower shells can be disassembled for replacement, and the protective sleeve 407 is used to protect the sealant barrel 408 from excessive wear.

[0035] Preferably, a spring 406 is provided between the upper shell 402 and the lower shell 410 .

[0036] Preferably, the union 3 is connected to the pinball disk 5 to ensure that the union 3 can rotate 360 ​​degrees. The pinball disk 5 includes a loading mechanism 501 and a rotating structure 502, and the union 3 is connected to the rotating structure 502.

[0037] Preferably, the upper joint 2032 and the lower joint 2031 both include a fixed head 201 and a fixed lead block 202, and the outer diameter of the fixed head 201 is smaller than the inner diameter of the body 1. The buckle type of the upper joint 2032 and the lower joint 2031 is consistent with the upper and lower connected tools. The upper joint 2032 is connected to the lifting wire 6 and then to the crane, and the lower joint 2031 is connected to the ball head quick connector 7 and then to the Roll-on connector on the salvaged coiled tubing.

[0038] The present invention also provides a method for fishing a coiled tubing through a core, comprising the following steps:

[0039] S1, well killing: prepare well killing fluid according to the shut-in pressure and formation pressure coefficient, reduce the pressure in the casing and coiled tubing to 0, and cut the coiled tubing;

[0040] S2. Use a workover rig to select a tubing of appropriate size and run it through the tubing until it encounters resistance;

[0041] S3, connect the through-core fishing coiled tubing device to the through-core fishing tubing, the through-core fishing coiled tubing tool can move up and down with the traveling block of the workover rig, the wire rope 2 is inserted into the through-core fishing tubing, the lower joint 2031 is connected to the coiled tubing, the tubing male thread 101 of the body 1 is connected to the wellhead tubing, the upper joint 2032 is connected to the crane, and the union 3 is connected to the pumping pipeline; the crane lifts a certain tonnage to prevent the coiled tubing from sliding down after the jam is removed;

[0042] S4, pressurizing the pressure port 412 by a hand pump to achieve dynamic sealing of the wire rope 2, so as to ensure that the device for drilling through the core and fishing the coiled tubing can move up and down with the traveling pulley of the workover rig;

[0043] S5. Circulate working fluid from the union joint 3 through the pumping equipment to carry debris and other debris from the blocked part of the tubing, i.e., the buried part of the coiled tubing, out of the ground through positive circulation, i.e., the tubing is injected into the casing and returned;

[0044] S6, keep the cycle, the traveling block lowers the tubing to deepen to continuously remove the obstruction outside the coiled tubing, when the tubing is lowered to the turntable, the connection between the tubing and the through-core fishing device needs to be disconnected; first disconnect the tubing male thread 101 from the wellhead tubing, then disconnect the ball head quick connector 7, pass the wire rope 2 into another through-core tubing, restore the connection of the ball head quick connector 7, and connect the tubing male thread 101 to the through-core tubing, so as to achieve continuous washing and remove the obstruction outside the coiled tubing;

[0045] S7. After the coiled tubing is unblocked, remove the through-core fishing device for the coiled tubing, and use a through-core rod with the same outer diameter as the coiled tubing to connect the coiled tubing. If the bottom tool of the coiled tubing can pass through the through-core tubing, place the tubing on the turntable of the workover rig, use the coiled tubing equipment to rewind the coiled tubing in the well, and then pull out the tubing; otherwise, reverse through-core fishing to pull out the tubing in the well, and then use the coiled tubing equipment to rewind the coiled tubing in the well.

[0046] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A device for fishing coiled tubing through a core, characterized in that: The invention comprises a body (1), a steel wire rope (2), a union joint (3) and a sealing mechanism (4); the upper end of the body (1) is connected to the sealing mechanism (4); the steel wire rope (2) passes through the sealing mechanism (4) and the body (1); the outer diameter of the body (1) is consistent with the outer diameter of the oil pipe; the two ends of the steel wire rope (2) are respectively provided with an upper joint (2032) and a lower joint (2031); the upper joint (2032) is used to be connected to a crane; the lower joint (2031) is used to be connected to a continuous oil pipe to be salvaged; the union joint (3) is arranged on the body (1); and the union joint (3) is connected to a pumping pipeline.

2. The device for fishing coiled tubing through a core according to claim 1, characterized in that: The sealing mechanism (4) comprises an upper shell (402), an overflow port (405), a sealing glue barrel (408), a lower shell (410) and a pressure port (412); the upper shell (402) and the lower shell (410) are connected by threads, a bell mouth (401) is provided at the upper end of the upper shell (402), an upper cushion block (403) and a baffle (404) are provided between the bell mouth (401) and the upper shell (402), and the overflow port (405) and the pressure port (412) are provided on the upper shell (402). On the shell (402), a lower pad (409) and a choke tube (411) are provided inside the lower shell (410), the sealing rubber barrel (408) is fixed between the upper pad (403) and the lower pad (409), the choke plate (404) and the choke tube (411) are used to prevent the hydraulic oil from overflowing when the pressure is applied from the pressure port (412), the steel wire rope (2) is inserted from the bell mouth (401), and the sealing rubber barrel (408) forms a seal with the steel wire rope (2) under the action of hydraulic loading.

3. The device for fishing coiled tubing through a core according to claim 2, characterized in that: A protective sheath (407) is provided on the outer side of the sealing rubber barrel (408).

4. The device for fishing coiled tubing through a core according to claim 2, characterized in that: A spring (406) is provided between the upper shell (402) and the lower shell (410).

5. The device for fishing coiled tubing through a core according to claim 1, characterized in that: The union joint (3) is connected to the pinball disk (5) to ensure that the union joint (3) can rotate 360 ​​degrees.

6. The device for fishing coiled tubing through a core according to claim 5, characterized in that: The pinball disk (5) comprises a loading mechanism (501) and a rotating structure (502), and the union (3) is connected to the rotating structure (502).

7. The device for fishing coiled tubing through a core according to claim 1, characterized in that: The upper joint (2032) and the lower joint (2031) both comprise a fixed head (201) and a fixed lead block (202); the outer diameter of the fixed head (201) is smaller than the inner diameter of the body (1); the upper joint (2032) is connected to a lifting wire (6) and then to a crane; the lower joint (2031) is connected to a ball head quick connector (7) and then to a Roll-on connector on a salvaged coiled tubing.

8. A method for salvaging a coiled tubing through a core, using the device for salvaging a coiled tubing through a core according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, well killing: prepare well killing fluid according to the shut-in pressure and formation pressure coefficient, reduce the pressure in the casing and coiled tubing to 0, and cut the coiled tubing; S2. Use a workover rig to select a tubing of appropriate size and run it through the tubing until it encounters resistance; S3, the through-core salvage coiled tubing device is connected to the through-core tubing, the through-core salvage coiled tubing tool can move up and down with the traveling pulley of the well repair rig, the wire rope (2) is inserted into the through-core tubing, the lower joint (2031) is connected to the ball head quick connector (7) and then connected to the Roll-on connector on the salvaged coiled tubing, the body (1) is connected to the wellhead tubing, the upper joint (2032) is connected to the lifting wire (6) and then connected to the crane, and the union (3) is connected to the pumping pipeline; S4, by applying pressure to the sealing mechanism (4), a dynamic seal of the steel wire rope (2) is achieved, so as to ensure that the device for salvaging the coiled tubing through the core can move up and down with the traveling pulley of the workover rig; S5. Circulate working fluid from the union (3) through a pumping device to carry debris and other debris from where the tubing is blocked, i.e. where the coiled tubing is stuck, out of the ground through a positive circulation method; S6, keep the cycle, the traveling block lowers the tubing deeper to continuously remove the obstruction outside the coiled tubing, when the tubing is lowered to the rotary table, the connection between the tubing and the through-core fishing device needs to be disconnected; first disconnect the tubing male thread (101) connected to the wellhead tubing, disconnect the connection from the ball head quick connector (7), pass the steel wire rope (2) through another through-core tubing, then restore the connection of the ball head quick connector (7) and the tubing male thread (101) connected to the through-core tubing, thereby achieving continuous washing and removing the obstruction outside the coiled tubing; S7. After the coiled tubing is unblocked, remove the through-core fishing device for the coiled tubing, and use a through-core rod with the same outer diameter as the coiled tubing to connect the coiled tubing. If the bottom tool of the coiled tubing can pass through the through-core tubing, place the tubing on the turntable of the workover rig, use the coiled tubing equipment to rewind the coiled tubing in the well, and then pull out the tubing; otherwise, reverse through-core fishing to pull out the tubing in the well, and then use the coiled tubing equipment to rewind the coiled tubing in the well.

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