A chemical-additionable dual-channel oil well tubing

Abstract

This utility model discloses a dual-channel oil well tubing string with chemical dosing capability, comprising: an oil layer casing, a large oil tubing sleeved inside the oil layer casing, a small oil tubing sleeved inside the large oil tubing, a changeover joint installed at the bottom end of the large oil tubing, a sealing insert installed at the bottom end of the small oil tubing, a sealing cylinder installed at the top end of the changeover joint, and the bottom end of the sealing insert being inserted into and sealed to the sealing cylinder. The small oil tubing is connected to the changeover joint through the insertion structure of the sealing insert and the sealing cylinder. A positive flow valve is installed on the side end of the sealing cylinder, one end of which connects to the annulus between the large and small oil tubing, and the other end of which connects to the oil layer. A pump is installed inside the small oil tubing. This utility model allows for chemical dosing through the annulus of the large and small oil tubing. The chemical mixes with the produced fluid from the oil layer through the positive flow valve, then enters the small oil tubing through the channel inside the changeover joint and the sealing insert, and is pumped to the surface by the pump. This solves the problem of chemical dosing not being possible in wells with dead oil rings in the annulus of the casing and casing.

Description

Technical Field

[0001] This utility model relates to the field of oil well production tubing technology, and in particular to a chemical-adding dual-channel oil well tubing. Background Technology

[0002] During oil well production, the formation water has complex properties; some is corrosive, some is prone to scaling, and some crude oil has a high wax content, making the tubing prone to wax formation. Usually, it is necessary to add corrosion inhibitors, scale inhibitors, and wax removers and preventers through the annulus. However, when the crude oil has a high wax content and a high pour point, dead oil rings are easily formed in the annulus. The presence of dead oil rings prevents the agents from being added to the well through the annulus, forcing the company to periodically inspect the pump, replace the tubing and sucker rod, etc., which is costly. Utility Model Content

[0003] The purpose of this invention is to provide a dual-channel oil well tubing string that can be used for chemical dosing. Chemicals are added through the annulus of the large and small tubings. The chemicals are mixed with the produced fluid from the oil layer through a positive flow valve, and then enter the small tubing through the inner channel of the changeover joint and the sealed insertion pipe. The solution is to pump the chemicals to the surface by the oil pump, thus solving the problem that chemicals cannot be added downhole in oil wells with dead oil rings in the annulus.

[0004] To achieve the purpose of this utility model, this utility model provides a chemical-additionable dual-flow-channel oil well tubing string, comprising: an oil layer casing, a large oil tubing sleeved inside the oil layer casing, a small oil tubing sleeved inside the large oil tubing, a changeover joint installed at the bottom end of the large oil tubing, a sealing insert installed at the bottom end of the small oil tubing, a sealing cylinder installed at the top end of the changeover joint, the bottom end of the sealing insert being inserted into and sealed to the sealing cylinder, the small oil tubing being connected to the changeover joint through the insertion structure of the sealing insert and the sealing cylinder, a positive flow valve being provided on the side end of the sealing cylinder, one end of the positive flow valve being connected to the annulus between the large and small oil tubing, the other end of the positive flow valve being connected to the oil layer, and a pumping unit being installed inside the small oil tubing.

[0005] As a preferred embodiment of this utility model, the top of the oil pump is connected to a sucker rod.

[0006] As a preferred embodiment of this utility model, the sealing tube is a through-tube structure, comprising an upper connector, an intermediate body, a lower connector, and a sealing element. The upper connector, intermediate body, and lower connector are sequentially threaded together. The upper end of the upper connector is threadedly connected to the bottom end of the small oil tube, and the lower end of the upper connector is a small-diameter section used to fit the sealing element. The upper end of the intermediate body is threadedly connected to the bottom end of the upper connector, and the upper end face of the intermediate body presses against the sealing element. The lower end of the intermediate body is a small-diameter section used to fit the sealing element. The upper end of the lower connector is threadedly connected to the lower end of the intermediate body, and the upper end face of the lower connector presses against the sealing element.

[0007] As a preferred embodiment of this utility model, the lower end face of the lower connector is provided with a horseshoe-shaped guide shoe.

[0008] As a preferred embodiment of this utility model, the sealing cylinder is a through-hole structure. The through-hole of the sealing cylinder includes a large-diameter section, a small-diameter section, and a step. The small-diameter section is located below the large-diameter section, and the top of the small-diameter section transitions to the bottom of the large-diameter section through the step. The bottom end of the sealing tube is inserted into the large-diameter section until it abuts against the step. The outer wall of the bottom end of the sealing cylinder is provided with external threads and is threadedly connected to the transformation joint.

[0009] As a preferred embodiment of this utility model, the adapter includes a body, a first threaded interface at the top of the body, a second threaded interface below the first threaded interface, the diameter of the second threaded interface being smaller than the diameter of the first threaded interface, the top of the second threaded interface transitioning to the bottom of the first threaded interface via an inclined surface, the first threaded interface being threadedly connected to the bottom of the large oil pipe, the second threaded interface being threadedly connected to the bottom of the sealing cylinder, and a central through hole and an oblique through hole being provided inside the body, the central through hole and the oblique through hole being arranged side by side, the central through hole communicating with the sealing cylinder, and the oblique through hole communicating with the large oil pipe.

[0010] As a preferred embodiment of this utility model, a lower oil pipe is threadedly connected to the bottom end of the central through hole, a plug is installed at the bottom end of the lower oil pipe, and a screen pipe is installed in the middle of the lower oil pipe.

[0011] As a preferred embodiment of this utility model, the positive flow valve is installed in the oblique through hole. The positive flow valve includes a valve seat, a valve ball, a spring, and a retaining ring. The retaining ring is installed at the bottom end of the oblique through hole, and the valve seat is located in the middle of the oblique through hole. The valve seat has a flared opening structure. The valve ball is installed at the opening of the valve seat, and the outer wall of the valve ball is fitted with the oblique surface of the valve seat to form a metal seal. One end of the spring is connected to the retaining ring, and the other end of the spring is connected to the valve ball.

[0012] Compared with the prior art, this utility model provides a chemical-additionable dual-channel oil well tubing string, which has the following beneficial effects:

[0013] This invention utilizes a method of adding chemicals through the annulus of both large and small tubing. The chemicals are mixed with the produced fluid from the oil layer via a forward flow valve, then enter the small tubing through the channel inside the changeover joint and a sealed insert, and are pumped to the surface by a pump. The same path can also be used for reverse circulation well washing; forward circulation well washing can also be achieved, with the chemicals returning from the annulus formed by the large tubing and casing. This solves the problem of chemicals not being able to be added downhole in wells with dead oil rings in the annulus. Furthermore, during normal production, due to the forward flow valve structure, crude oil produced from the formation cannot enter the annulus of both large and small tubing via the changeover joint, thus preventing the formation of dead oil rings in the annulus. This significantly extends the time required for pump inspection, tubing replacement, sucker rod replacement, and other operations, reducing production costs. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model;

[0015] Figure 2 This is a schematic diagram of the sealing cannula structure of this utility model;

[0016] Figure 3 This is a schematic diagram of the sealing cylinder structure of this utility model;

[0017] Figure 4 This is a schematic diagram of the transformation connector structure of this utility model.

[0018] 1 is the oil layer casing, 2 is the large oil pipe, 3 is the small oil pipe, 4 is the changeover joint, 5 is the sealing insert, 6 is the sealing cylinder, 7 is the positive check valve, 8 is the oil layer, 9 is the oil pump, 10 is the sucker rod, 11 is the plug, 12 is the screen pipe, 13 is the upper joint, 14 is the intermediate body, 15 is the lower joint, 16 is the seal, 17 is the horseshoe-shaped guide shoe, 18 is the large diameter section, 19 is the small diameter section, 20 is the step, 21 is the body, 22 is the first threaded interface, 23 is the second threaded interface, 24 is the central through hole, 25 is the oblique through hole, 26 is the lower oil pipe, 27 is the valve seat, 28 is the valve ball, 29 is the spring, 30 is the retaining ring, and 31 is the dead oil ring. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] Please see Figures 1-4This utility model provides a chemical-additionable dual-channel oil well tubing string, comprising: an oil layer casing 1, a large oil tubing 2 sleeved inside the oil layer casing 1, a small oil tubing 3 sleeved inside the large oil tubing 2, a changeover joint 4 installed at the bottom end of the large oil tubing 2, a sealing insert 5 installed at the bottom end of the small oil tubing 3, a sealing cylinder 6 installed at the top end of the changeover joint 4, the bottom end of the sealing insert 5 being inserted into and sealed to the sealing cylinder 6, the small oil tubing 3 being connected to the changeover joint 4 through the insertion structure of the sealing insert 5 and the sealing cylinder 6, a positive flow valve 7 being provided on the side end of the sealing cylinder 6, one end of the positive flow valve 7 being connected to the annulus between the large oil tubing 2 and the small oil tubing 3, and the other end of the positive flow valve 7 being connected to the oil layer 8, and a pumping pump 9 being installed inside the small oil tubing 3.

[0021] In one embodiment of the present invention, the top of the oil pump 9 is connected to a sucker rod 10.

[0022] In one embodiment of this utility model, the sealing tube 5 is a through-tube structure and includes an upper connector 13, an intermediate body 14, a lower connector 15, and a sealing element 16. The upper connector 13, the intermediate body 14, and the lower connector 15 are sequentially threaded together. The upper end of the upper connector 13 is threadedly connected to the bottom end of the small oil tube 3. The lower end of the upper connector 13 is a small-diameter section used to fit the sealing element 16. The upper end of the intermediate body 14 is threadedly connected to the bottom end of the upper connector 13, and the upper end face of the intermediate body 14 presses against the sealing element 16. The lower end of the intermediate body 14 is a small-diameter section used to fit the sealing element 16. The upper end of the lower connector 15 is threadedly connected to the lower end of the intermediate body 14, and the upper end face of the lower connector 15 presses against the sealing element 16.

[0023] In one embodiment of this utility model, the lower end face of the lower connector 15 is provided with a horseshoe-shaped guide shoe 17.

[0024] In one embodiment of this utility model, the sealing cylinder 6 is a through-hole structure. The through hole of the sealing cylinder 6 includes a large diameter section 18, a small diameter section 19, and a step 20. The small diameter section 19 is located below the large diameter section 18, and the top of the small diameter section 19 transitions to the bottom of the large diameter section 18 through the step 20. The bottom end of the sealing tube 5 is inserted into the large diameter section 18 until it abuts against the step 20. The outer wall of the bottom end of the sealing cylinder 6 is provided with external threads and is threadedly connected to the transformation connector 4.

[0025] In one embodiment of this utility model, the adapter 4 includes a body 21. The top of the body 21 is provided with a first threaded interface 22, and a second threaded interface 23 is provided below the first threaded interface 22. The diameter of the second threaded interface 23 is smaller than the diameter of the first threaded interface 22. The top of the second threaded interface 23 transitions to the bottom of the first threaded interface 22 through an inclined surface. The first threaded interface 22 is threadedly connected to the bottom of the large oil pipe 2, and the second threaded interface 23 is threadedly connected to the bottom of the sealing cylinder 6. The body 21 has a central through hole 24 and an oblique through hole 25, which are arranged side by side. The central through hole 24 is connected to the sealing cylinder 6, and the oblique through hole 25 is connected to the large oil pipe 2.

[0026] In one embodiment of this utility model, the bottom end of the central through hole 24 is threadedly connected to a lower oil pipe 26, a plug 11 is installed at the bottom end of the lower oil pipe 26, and a screen pipe 12 is installed in the middle of the lower oil pipe 26.

[0027] In one embodiment of this utility model, the positive flow valve 7 is installed in the oblique through hole 25. The positive flow valve 7 includes a valve seat 27, a valve ball 28, a spring 29, and a retaining ring 30. The retaining ring 30 is installed at the bottom end of the oblique through hole 25. The valve seat 27 is located in the middle of the oblique through hole 25 and has a flared opening structure. The valve ball 28 is installed at the opening of the valve seat 27, and the outer wall of the valve ball 28 is fitted with the oblique surface of the valve seat 27 to form a metal seal. One end of the spring 29 is connected to the retaining ring 30, and the other end of the spring 29 is connected to the valve ball 28.

[0028] The above are merely preferred embodiments of this utility model, but the scope of protection of this utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this utility model, based on the technical solution and inventive concept of this utility model, should be included within the scope of protection of this utility model.

Claims

1. A chemical-additionable dual-channel oil well tubing string, characterized in that, include: An oil layer casing (1) is provided, with a large oil pipe (2) inside the casing (1) and a small oil pipe (3) inside the large oil pipe (2). A changeover joint (4) is installed at the bottom of the large oil pipe (2), and a sealing insert (5) is installed at the bottom of the small oil pipe (3). A sealing cylinder (6) is installed at the top of the changeover joint (4). The bottom of the sealing insert (5) is inserted into the sealing cylinder (6) for sealing connection. The small oil pipe (3) is connected to the changeover joint (4) through the insertion structure of the sealing insert (5) and the sealing cylinder (6). A positive flow valve (7) is provided on the side of the sealing cylinder (6). One end of the positive flow valve (7) is connected to the annulus between the large oil pipe (2) and the small oil pipe (3), and the other end of the positive flow valve (7) is connected to the oil layer (8). An oil pump (9) is installed inside the small oil pipe (3).

2. The chemical-additionable dual-channel oil well tubing string according to claim 1, characterized in that: The top of the oil pump (9) is connected to a sucker rod (10).

3. The chemical-additionable dual-channel oil well tubing string according to claim 1, characterized in that: The sealing tube (5) is a through tube structure and includes an upper connector (13), an intermediate body (14), a lower connector (15), and a seal (16). The upper connector (13), the intermediate body (14), and the lower connector (15) are connected by threads in sequence. The upper end of the upper connector (13) is threaded to the bottom end of the small oil tube (3). The lower end of the upper connector (13) is set as a small diameter section, which is used to fit the seal (16). The upper end of the intermediate body (14) is threaded to the bottom end of the upper connector (13), and the upper end face of the intermediate body (14) is pressed against the seal (16). The lower end of the intermediate body (14) is set as a small diameter section, which is used to fit the seal (16). The upper end of the lower connector (15) is threaded to the lower end of the intermediate body (14), and the upper end face of the lower connector (15) is pressed against the seal (16).

4. The chemical-additionable dual-channel oil well tubing string according to claim 3, characterized in that: The lower end face of the lower connector (15) is provided with a horseshoe-shaped guide shoe (17).

5. A chemical-additionable dual-channel oil well tubing string according to claim 1, characterized in that: The sealing cylinder (6) is a through-hole structure. The through hole of the sealing cylinder (6) includes a large diameter section (18), a small diameter section (19) and a step (20). The small diameter section (19) is located below the large diameter section (18), and the top of the small diameter section (19) transitions to the bottom of the large diameter section (18) through the step (20). The bottom end of the sealing tube (5) is inserted into the large diameter section (18) until it reaches the step (20). The outer wall of the bottom end of the sealing cylinder (6) is provided with external threads and is threadedly connected to the transformation connector (4).

6. The chemical-additionable dual-channel oil well tubing string according to claim 1, characterized in that: The adapter (4) includes a body (21), the top of the body (21) is provided with a first threaded interface (22), the bottom of the first threaded interface (22) is provided with a second threaded interface (23), the diameter of the second threaded interface (23) is smaller than the diameter of the first threaded interface (22), the top of the second threaded interface (23) transitions to the bottom of the first threaded interface (22) through an inclined surface, the first threaded interface (22) is threadedly connected to the bottom of the large oil pipe (2), the second threaded interface (23) is threadedly connected to the bottom of the sealing cylinder (6), the body (21) is provided with a central through hole (24) and an oblique through hole (25), the central through hole (24) and the oblique through hole (25) are arranged side by side, the central through hole (24) is connected to the sealing cylinder (6), and the oblique through hole (25) is connected to the large oil pipe (2).

7. A chemical-additionable dual-channel oil well tubing string according to claim 6, characterized in that: The bottom end of the central through hole (24) is threadedly connected to the lower oil pipe (26), the bottom end of the lower oil pipe (26) is fitted with a plug (11), and the middle of the lower oil pipe (26) is fitted with a screen pipe (12).

8. A chemical-additionable dual-channel oil well tubing string according to claim 6, characterized in that: The positive flow valve (7) is installed in the oblique through hole (25). The positive flow valve (7) includes a valve seat (27), a valve ball (28), a spring (29), and a retaining ring (30). The retaining ring (30) is installed at the bottom end of the oblique through hole (25). The valve seat (27) is opened in the middle of the oblique through hole (25). The valve seat (27) is designed with a flared opening structure. The valve ball (28) is installed at the opening of the valve seat (27), and the outer wall of the valve ball (28) is fitted with the oblique surface of the valve seat (27) to form a metal seal. One end of the spring (29) is connected to the retaining ring (30), and the other end of the spring (29) is connected to the valve ball (28).

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