Coiled tubing hydraulic cement throwing device and cement throwing method thereof

Abstract

According to the continuous oil pipe hydraulic cement throwing device and the cement throwing method thereof, the original well liquid level is not damaged, and the one-time cement injection success rate of a leakage well can be greatly increased. The mortar throwing device comprises a continuous oil pipe and a mortar throwing barrel which are communicated, the continuous oil pipe is communicated with a ground hydraulic pump set, the mortar throwing barrel comprises a piston rod and a hollow piston fixedly connected to the bottom end of the piston rod, the outer wall of the piston rod is fixedly sleeved with a shearing thread ring, the shearing thread ring is connected with a cylinder cover through a plurality of safety pins, and the piston rod is sleeved with the cylinder cover; the outer wall of the cylinder cover is slidably connected with the inner wall of the cylinder barrel, the piston is sleeved with the cylinder barrel, and the outer wall of the piston is fixedly connected with the inner wall of the cylinder barrel. An extrusion cavity is formed between the inner wall of the cylinder cover and the outer wall of the piston rod, so that force for cutting off the safety pin is transmitted through the extrusion cavity, and the piston rod and the cylinder cover can slide relatively after the safety pin is cut off; the bottom end of the cylinder barrel is connected with a plastic bottom plug through a plurality of iron shear pins, and cement ash is stored in the space between the piston in the cylinder barrel and the plastic bottom plug.

Description

Technical Field

[0001] The invention belongs to the field of oil field downhole operations, relates to an oil and gas well ash injection construction process, and specifically relates to a continuous oil pipe hydraulic ash injection device and an ash injection method thereof. Background Art

[0002] Cement plugging, commonly known as cement injection, is the most commonly used method for sealing the formation. Its purpose is to prevent fluid leakage and pressure transmission between formations. However, for oil and gas wells with serious leakage and unable to establish circulation, ordinary cement injection process cannot be completed. Generally, plugging process measures need to be taken. After the circulation is established, the cement injection process is implemented. The steps are usually to use cement temporary plugging agent for temporary plugging construction first, and then implement ordinary cement injection process. Due to the different pressure-bearing effect of temporary plugging agent in each well, the cement surface sinks, and more than 50% of temporary plugging wells also need secondary cement injection; in addition, some wells use sand filling process, and there is no other oil layer on the cement surface. Cement is directly injected on the sand surface, with a success rate of 100%, but interlayer cement injection cannot be completed. The cost and time cost of sand filling process are high. More than 80% of wells need secondary sand filling or high sand flushing on the sand surface to maintain the stability of the sand surface. After the sand surface is still, the sand surface needs to be re-explored. In order to improve the one-time success rate of cement injection in leaking wells, a study on the hydraulic cement injection process of continuous tubing was carried out. Summary of the invention

[0003] In order to overcome the shortcomings of the prior art, the present invention provides a continuous oil pipe hydraulic ash injection device and a ash injection method thereof, which uses a continuous oil pipe to send an ash injection cylinder into a predetermined ash injection well section, and the ash injection process is completed by pressure injection without damaging the original well liquid level. The original well static liquid level is used to support a 10-20m ash column, which can greatly improve the one-time success rate of ash injection in a lost well.

[0004] The technical solution adopted by the present invention to solve the technical problem is:

[0005] A continuous oil pipe hydraulic ash throwing device comprises a connected continuous oil pipe and an ash throwing cylinder, the continuous oil pipe is connected to a ground hydraulic pump group, the ash throwing cylinder comprises a piston rod and a hollow piston fixedly connected to the bottom end of the piston rod, the outer wall of the piston rod is fixedly sleeved with a shear thread ring, the shear thread ring is connected to the cylinder cover through a plurality of safety pins, and the cylinder cover is sleeved on the outside of the piston rod; the outer wall of the cylinder cover is slidably connected to the inner wall of the cylinder barrel, the cylinder barrel is sleeved on the outside of the piston and the outer wall of the piston is fixedly connected to the inner wall of the cylinder barrel; an extrusion cavity located above the shear thread ring is formed between the inner wall of the cylinder cover and the outer wall of the piston rod, a hole communicating with the extrusion cavity is formed on the rod body of the piston rod, and the force of cutting off the safety pin is transmitted to the extrusion cavity through the hole, and the piston rod and the cylinder cover can slide relatively after the safety pin is cut off; the bottom end of the cylinder barrel is connected to a plastic bottom plug through a plurality of iron shear pins, and cement ash is stored in the space between the piston and the plastic bottom plug inside the cylinder barrel.

[0006] As a further implementation scheme of the present invention, a through cavity is provided in the middle of the plastic bottom plug, and a check valve cover, a spring and a steel ball are provided in the cavity which are connected in sequence from top to bottom.

[0007] As a further embodiment of the present invention, an O-ring is provided between the outer wall of the plastic bottom plug and the inner wall of the cylinder.

[0008] As a further embodiment of the present invention, a V-shaped piston combination sealing ring is provided between the outer wall of the piston and the inner wall of the cylinder, and the V-shaped piston combination sealing ring is compressed and limited between the outer wall of the piston and the inner wall of the cylinder by a sealing ring gland.

[0009] As a further embodiment of the present invention, the sealing ring gland is fixedly connected between the outer wall of the bottom end of the piston and the inner wall of the cylinder barrel by means of a hexagonal cone-end set screw.

[0010] As a further embodiment of the present invention, a multi-stage sealing ring a is provided between the outer wall of the piston rod and the inner wall of the cylinder head.

[0011] As a further embodiment of the present invention, a sealing ring b is provided between the outer wall of the cylinder cover and the inner wall of the cylinder barrel.

[0012] As a further implementation scheme of the present invention, the coiled tubing is connected to a hydraulic safety joint via an external connector, the hydraulic safety joint is connected to a buckle changer, and the buckle changer is fixedly connected to the top of the cylinder head.

[0013] A method for feeding ash using a coiled tubing hydraulic ash feeding device, the steps are as follows:

[0014] Prepare the cement cylinder: store cement ash in the lower space of the cylinder. After a sufficient amount of cement ash is stored, connect the plastic bottom plug to the bottom of the cylinder through a number of iron shear nails to accommodate the cement ash in the space between the piston inside the cylinder and the plastic bottom plug;

[0015] Connect the coiled tubing: connect the cement ash cylinder storing cement ash to the coiled tubing, and use the coiled tubing to send the cement ash device to the preset position underground;

[0016] Connect the hydraulic pump group: connect the coiled tubing to the hydraulic pump group so that the ground hydraulic pump group can provide the pressure required for the ash throwing action;

[0017] Apply pressure: Start the hydraulic pump group to transmit the hydraulic pressure to the continuous oil pipe and the ash barrel. The hydraulic pressure enters the extrusion chamber through the hole on the piston rod body, applies force to cut off the safety pin, and continues to pump in pressure to push the piston rod to slide downward along the inner wall of the cylinder cover, and drives the cylinder barrel to slide downward through the piston; continue to pump in pressure until the iron shear nails are cut off under the pressure, so that the plastic bottom plug is separated from the cylinder barrel and falls off, maintain the pressure and continue to pump in, the cylinder barrel continues to move downward, and pushes the cement ash to the preset ash injection position. After all the cement ash has fallen, pull out the continuous oil pipe and take out the ash barrel to complete the ash injection process.

[0018] The beneficial effects of the present invention include:

[0019] The ash injection device and ash injection method do not need to replenish the downhole liquid level, do not need to backwash, etc. to destroy the static liquid level in the well, and use the static liquid level in the oil well to retain 10-20m of ash surface. There is no need to establish circulation, so the static liquid level in the well is protected. Especially for wells with serious leakage or wells that cannot establish circulation and have static liquid surface, ash injection wells with sand surface, and small-dose 3-5m ash plugs between layers, the continuous tubing ash injection process can be completed at one time, and the success rate reaches more than 90%. The ash injection device and ash injection method can be used for wells with serious leakage, ash injection wells with sand surface, and ash injection measures with small-dose 3-5m ash plugs between layers, saving the cost of temporary plugging agents for oil and gas wells, reducing construction procedures, improving the one-time success rate of continuous tubing ash injection, shortening the operation cycle, and achieving quality improvement and efficiency increase, and has a relatively broad application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of the ash throwing device of the present invention;

[0021] Figure 2 yes Figure 1 AA cross-section diagram;

[0022] Figure 3 yes Figure 1 BB cross-section diagram;

[0023] Figure 4 yes Figure 1 CC cross-section diagram.

[0024] In the figure: 1-piston rod, 2-cylinder head, 3-shear thread ring, 4-piston, 5-sealing ring gland, 6-cylinder barrel, 7-plastic bottom plug, 8-check valve cover, 9-iron shear nail, 10-steel ball, 11-spring, 12-O-type sealing ring, 13-hexagonal cone end set screw, 14-V-type piston combination sealing ring, 15-safety pin, 16-sealing ring a, 17-sealing ring b, 18-hole, 19-extrusion chamber. DETAILED DESCRIPTION

[0025] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper", "lower", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "a", "b", etc. are only used to distinguish components, and cannot be understood as indicating or implying relative importance.

[0027] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0028] Example 1

[0029] A continuous tubing hydraulic ash injection device and ash injection method thereof, using continuous tubing to send an ash injection tube into a predetermined ash injection well section, and completing the ash injection process by pressure injection. On the basis of not destroying the original well liquid level, the original well static liquid level is used to support a 10-20m ash column, which can greatly improve the one-time success rate of ash injection in a leaking well.

[0030] Specifically, the continuous tubing hydraulic ash-feeding device has a continuous tubing connected to a hydraulic safety joint through an external connector, the hydraulic safety joint is connected to a buckle changer, the buckle changer is connected to an ash-feeding barrel, and the continuous tubing is connected to a ground hydraulic pump group.

[0031] like Figure 1 As shown, the ash throwing cylinder includes a piston rod 1 and a hollow piston 4 fixedly connected to the bottom end of the piston rod 1. The outer wall of the piston rod 1 is fixedly sleeved with a shear thread ring 3. Figure 1 and Figure 3 The shear thread ring 3 is connected to the cylinder cover 2 through two safety pins 15. The cylinder cover 2 is mounted on the outside of the piston rod 1. A multi-stage sealing ring a16 is provided between the outer wall of the piston rod 1 and the inner wall of the cylinder cover 2;

[0032] The outer wall of the cylinder head 2 is slidably connected with the inner wall of the cylinder barrel 6, and a sealing ring b17 is provided between the outer wall of the cylinder head 2 and the inner wall of the cylinder barrel 6; the cylinder barrel 6 is mounted on the outside of the piston 4 and the outer wall of the piston 4 is fixedly connected with the inner wall of the cylinder barrel 6, and a V-shaped piston combination sealing ring 14 is provided between the outer wall of the piston 4 and the inner wall of the cylinder barrel 6, and the V-shaped piston combination sealing ring 14 is compressed and limited between the outer wall of the piston 4 and the inner wall of the cylinder barrel 6 by the sealing ring gland 5, and the sealing ring gland 5 is fixedly connected between the outer wall of the bottom end of the piston 4 and the inner wall of the cylinder barrel 6 by the hexagonal cone end set screw 13.

[0033] refer to Figure 1 and Figure 2 An extrusion chamber 19 is formed between the inner wall of the cylinder head 2 and the outer wall of the piston rod 1, and is located above the shear thread ring 3. A hole 18 communicating with the extrusion chamber 19 is formed on the body of the piston rod 1, so as to transmit the force of cutting off the safety pin 15 to the extrusion chamber 19 through the hole 18. After the safety pin 15 is cut off, the piston rod 1 and the cylinder head 2 can slide relative to each other;

[0034] refer to Figure 1 and Figure 4 The bottom end of the cylinder 6 is connected to a plastic bottom plug 7 through 8 iron shear nails 9 evenly distributed in the circumference, and an O-ring 12 is arranged between the outer wall of the plastic bottom plug 7 and the inner wall of the cylinder 6; cement ash is stored in the space between the piston 4 and the plastic bottom plug 7 inside the cylinder 6. A through cavity is arranged in the middle of the plastic bottom plug 7, and a check valve cover 8, a spring 11, and a steel ball 10 are arranged in sequence from top to bottom in the cavity.

[0035] Based on the above structural setting, the ash feeding method of the coiled tubing hydraulic ash feeding device has the following steps:

[0036] Prepare the cement cylinder: store cement ash in the lower space of the cylinder 6. After a sufficient amount of cement ash is stored, connect the plastic bottom plug 7 to the bottom end of the cylinder 6 through a number of iron shear nails 9 to accommodate the cement ash in the space between the piston 4 and the plastic bottom plug 7 inside the cylinder 6;

[0037] Connect the coiled tubing: connect the cement ash cylinder storing cement ash to the coiled tubing, and use the coiled tubing to send the cement ash device to the preset position underground;

[0038] Connect the hydraulic pump group: connect the coiled tubing to the hydraulic pump group so that the ground hydraulic pump group can provide the pressure required for the ash throwing action;

[0039] Apply pressure: Start the hydraulic pump group to transmit the hydraulic pressure to the continuous oil pipe and the ash barrel. The hydraulic pressure enters the extrusion chamber 19 through the hole 18 on the rod body of the piston rod 1, and force is applied to cut off the safety pin 15. Continue to pump in pressure, push the piston rod 1 to slide downward along the inner wall of the cylinder cover 2, and drive the cylinder 6 to slide downward through the piston 4; continue to pump in pressure until the iron shear nails 9 are cut off under the pressure, so that the plastic bottom plug 7 is separated from the cylinder 6 and falls off, maintain the pressure and continue to pump in, the cylinder 6 continues to move downward, and pushes the cement ash to fall into the preset ash injection position. After all the cement ash has fallen, pull out the continuous oil pipe and take out the ash barrel to complete the ash injection process. Preferably, since a single-flow valve cover 8, a spring 11, and a ∮12mm steel ball 10 are sequentially connected from top to bottom in the through cavity in the middle of the plastic bottom plug 7, on the one hand, the single-flow valve cover 8 can prevent backflow, and on the other hand, the pressure from the hydraulic pump group is transmitted downward through the single-flow valve cover 8, so that the steel ball 10 is pushed downward to pull the spring 11, thereby assisting the smooth falling off of the plastic bottom plug 7, and further ensuring the successful implementation of the ash throwing action.

[0040] Based on the above implementation scheme, the principle of the present invention is: utilizing the static liquid level of the original well, without breaking the balance of the static liquid level, using a continuous oil pipe to send the ash injection barrel to the predetermined position, cutting off the safety pin by ground pressure, continuing to pressurize, pushing the piston and the cylinder head to relative displacement, the plastic bottom plug at the bottom end of the ash injection barrel is knocked off, continuing to pressurize, leaving the cement slurry at the ash injection position, pulling out the continuous oil pipe to take out the ash injection barrel, and completing the ash injection process; at the same time, research is done on the slow setting of cement slurry, precise calibration of the depth of the continuous oil pipe into the well, etc., to ensure the ash injection accuracy of the continuous oil pipe and the one-time success rate of ash injection.

[0041] Application Example 1

[0042] Construction purpose: lime injection construction in a well

[0043] Pipe string structure: 2.0〃 coiled tubing + external connector + hydraulic safety joint + buckle changer + φ114mm ash throwing cylinder.

[0044] Construction process: For a well with serious leakage, 5.5 tons of cement temporary plugging agent was first used for temporary plugging of oil and gas wells. Due to the different pressure-bearing effects of the temporary plugging agent, the cement surface sank, resulting in cement injection failure. Therefore, a continuous tubing hydraulic cement injection device was used to inject cement, and it went down to the designed predetermined position. The bottom hydraulic pump group was turned on to increase the pressure to 14.5MPa to cut off the two safety pins. At this time, the injection pressure was continued. The 8 iron shear nails of the plastic bottom plug were cut off under a thrust of about 3.2 tons, and the plastic bottom plug fell off. At this time, the injection pressure was continued, and the cylinder continued to move downward to push 200 liters of cement slurry into the predetermined position. After the injection was completed, the cement injection of the leaking well was successful at one time.

[0045] Conclusion: This construction does not need to replenish the downhole liquid level, backwash, etc. to destroy the static liquid level in the well. It uses the static liquid level in the oil well to retain 15m of ash surface. There is no need to establish a circulation, and the ash injection process is completed in one go, reducing construction processes, shortening the operation cycle, and achieving quality and efficiency improvements.

[0046] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A coiled tubing hydraulic ash throwing device, characterized in that: The utility model comprises a continuous oil pipe and an ash throwing cylinder which are connected to each other. The continuous oil pipe is connected to a ground hydraulic pump group. The ash throwing cylinder comprises a piston rod (1) and a hollow piston (4) fixedly connected to the bottom end of the piston rod (1). The outer wall of the piston rod (1) is fixedly sleeved with a shear thread ring (3). The shear thread ring (3) is connected to a cylinder cover (2) through a plurality of safety pins (15). The cylinder cover (2) is sleeved on the outside of the piston rod (1); the outer wall of the cylinder cover (2) is slidably connected to the inner wall of a cylinder barrel (6). The cylinder barrel (6) is sleeved on the outside of the piston (4) and the outer wall of the piston (4) is fixedly connected to the inner wall of the cylinder barrel (6); the cylinder cover (2) An extrusion chamber (19) located above the shear thread ring (3) is formed between the inner wall and the outer wall of the piston rod (1); a hole (18) communicating with the extrusion chamber (19) is formed on the body of the piston rod (1) for transmitting a force for cutting off the safety pin (15) to the extrusion chamber (19) through the hole (18); after the safety pin (15) is cut off, the piston rod (1) and the cylinder cover (2) can slide relative to each other; the bottom end of the cylinder barrel (6) is connected to a plastic bottom plug (7) through a plurality of iron shear nails (9); cement ash is stored in the space between the piston (4) and the plastic bottom plug (7) inside the cylinder barrel (6).

2. A coiled tubing hydraulic ash throwing device according to claim 1, characterized in that: A through cavity is provided in the middle of the plastic bottom plug (7), and a check valve cover (8), a spring (11), and a steel ball (10) are provided in the cavity from top to bottom, which are connected in sequence.

3. A coiled tubing hydraulic ash throwing device according to claim 2, characterized in that: An O-type sealing ring (12) is provided between the outer wall of the plastic bottom plug (7) and the inner wall of the cylinder barrel (6).

4. The coiled tubing hydraulic ash throwing device according to claim 1, characterized in that: A V-shaped piston combination sealing ring (14) is provided between the outer wall of the piston (4) and the inner wall of the cylinder barrel (6). The V-shaped piston combination sealing ring (14) is compressed and limited between the outer wall of the piston (4) and the inner wall of the cylinder barrel (6) by a sealing ring gland (5).

5. A coiled tubing hydraulic ash throwing device according to claim 4, characterized in that: The sealing ring gland (5) is fixedly connected between the outer wall of the bottom end of the piston (4) and the inner wall of the cylinder (6) by means of a hexagonal cone-end set screw (13).

6. The coiled tubing hydraulic ash throwing device according to claim 1, characterized in that: A multi-stage sealing ring a (16) is provided between the outer wall of the piston rod (1) and the inner wall of the cylinder cover (2).

7. The coiled tubing hydraulic ash throwing device according to claim 1, characterized in that: A sealing ring b (17) is provided between the outer wall of the cylinder cover (2) and the inner wall of the cylinder barrel (6).

8. A coiled tubing hydraulic ash throwing device according to any one of claims 1 to 7, characterized in that: The coiled oil pipe is connected to a hydraulic safety joint via an external connector, the hydraulic safety joint is connected to a buckle changer, and the buckle changer is fixedly connected to the top of the cylinder cover (2).

9. A method for applying ash to a coiled tubing hydraulic ash applying device, characterized in that: Here are the steps: Prepare the cement cylinder: store cement ash in the lower space of the cylinder (6), and after a sufficient amount of cement ash is stored, connect the plastic bottom plug (7) to the bottom end of the cylinder (6) through a plurality of iron shear nails (9) to accommodate the cement ash in the space between the piston (4) inside the cylinder (6) and the plastic bottom plug (7); Connect the coiled tubing: connect the cement ash cylinder storing cement ash to the coiled tubing, and use the coiled tubing to send the cement ash device to the preset position underground; Connect the hydraulic pump group: connect the coiled tubing to the hydraulic pump group so that the ground hydraulic pump group can provide the pressure required for the ash throwing action; Applying pressure: Start the hydraulic pump group to transmit the hydraulic pressure to the continuous oil pipe and the ash injection barrel. The hydraulic pressure enters the extrusion chamber (19) through the hole (18) on the rod body of the piston rod (1), applies force to cut off the safety pin (15), and continues to pump in pressure to push the piston rod (1) to slide downward along the inner wall of the cylinder cover (2), and drive the cylinder barrel (6) to slide downward through the piston (4); continue to pump in pressure until the iron shear nails (9) are cut off under the pressure so that the plastic bottom plug (7) separates from the cylinder barrel (6) and falls off, maintain the pressure and continue to pump in, the cylinder barrel (6) continues to move downward, and pushes the cement ash to fall into the preset ash injection position. After all the cement ash has fallen, the continuous oil pipe is pulled out and the ash injection barrel is taken out to complete the ash injection process.

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