Mechanical scale removal device for water injection string test passage

Abstract

This utility model discloses a mechanical descaling device for a water injection tubing test channel, including a rope cap connected to the lower end of a steel wire rope, a weight rod connected below the rope cap, a threaded joint connected to the lower end of the weight rod, a central rod connected to the lower end of the threaded joint, a scraper guide sleeve fitted around the middle section of the central rod with a clearance fit, and a spiral scraper blade wound around the outer circumference of the scraper guide. A guide cone is screwed onto the lower end of the central rod. An upper spring is fitted onto the upper end of the central rod, located between the upper end of the scraper guide and the bottom of the threaded joint. A lower spring is fitted onto the lower end of the central rod, located between the lower end of the scraper guide and the top of the guide cone. This mechanical descaling device for a water injection tubing test channel can handle hard scale layers in narrow flow channels of multi-layer injection well tubing and water distributor locations, meeting the needs of normal water injection well testing and avoiding the risk of testing instruments and descaling tools getting stuck during testing and descaling.

Description

Technical Field

[0001] This utility model relates to a descaling device for oilfield water injection wells, and more particularly to a mechanical descaling device for a water injection tubing test channel, belonging to the technical field of downhole descaling tools. Background Technology

[0002] During long-term operation, oilfield water injection wells experience scaling due to factors such as chemical incompatibility between formation water and injected water, temperature and pressure changes, and microbial activity. This scaling problem, especially at the water distributor, becomes increasingly severe. Consequently, during water injection well testing, testing instruments encounter obstacles or jams, making it impossible to complete relevant tests and thus hindering the assessment of water injection effectiveness, ultimately impacting oilfield development.

[0003] Some injection wells have severe scaling and fail to meet injection standards. If the testing and adjustment instruments still encounter obstacles after measures such as hot washing, well cleaning operations will be arranged. The cost of well cleaning operations for a single well is around 200,000 yuan, which greatly affects the development efficiency of the oilfield.

[0004] Currently, oilfields mainly employ physical, chemical, and mechanical methods for descaling. Physical descaling methods, such as high-pressure water jet descaling and ultrasonic descaling, have high equipment costs. Improper operation of high-pressure jet descaling can easily lead to safety hazards, and ultrasonic waves attenuate rapidly in long-distance pipelines, resulting in uneven wellbore cleaning. Chemical acid washing descaling: Acids can easily corrode downhole tubing and tools, easily causing secondary precipitation and acid-sensitive damage to the formation. Mechanical descaling: Currently used mechanical descaling tools are prone to jamming due to uneven scale buildup, requiring additional well workover operations. It is also labor-intensive, requiring frequent changes of different sized tools downhole, and has low descaling efficiency, with a success rate of less than 5%. Utility Model Content

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, and such simplifications or omissions should not be construed as limiting the scope of the present invention.

[0006] In view of the problems existing in the above and / or prior art, this utility model is proposed.

[0007] The purpose of this invention is to overcome the problems existing in the prior art and provide a mechanical descaling device for the test channel of a water injection tubing. This device can handle the hard scale layer in the narrow flow channels of multi-layer sub-injection well tubing and water distributor positions, ensure the integrity of the original adjustment function of the water distributor, meet the needs of normal testing of water injection wells, and avoid the risk of testing instruments and descaling tools getting stuck during testing and descaling.

[0008] To solve the above technical problems, this utility model provides a mechanical descaling device for a water injection pipe test channel, including a rope cap connected to the lower end of a steel wire rope, a weight rod connected below the rope cap, a threaded joint connected to the lower end of the weight rod, a central rod connected to the lower end of the threaded joint, a scraper guide tube fitted around the middle section of the central rod, the scraper guide tube and the central rod being clearance-fitted, a spiral scraper blade wound around the outer circumference of the scraper guide tube, and a guide cone screwed onto the lower end of the central rod.

[0009] As a preferred embodiment of this utility model, an upper spring is fitted onto the upper end of the central rod, and the upper spring is located between the upper end of the scraper guide tube and the bottom of the threaded joint.

[0010] As a further preferred embodiment of this utility model, a lower spring is fitted at the lower end of the central rod, and the lower spring is located between the lower end of the scraper guide tube and the top of the guide cone.

[0011] As a further preferred embodiment of this utility model, the upper end of the center rod is also screwed with a lock nut, the top of the lock nut abutting against the bottom of the threaded joint, and the upper spring is located between the upper end of the scraper guide tube and the bottom of the lock nut.

[0012] As a further preferred embodiment of this utility model, a lower lock nut is screwed to the lower end of the center rod, the bottom of the lower lock nut is pressed against the top of the guide cone, and the lower spring is located between the lower end of the lower spring and the top of the guide cone.

[0013] As a further preferred embodiment of this utility model, the spiral scraper blade is olive-shaped with a large diameter in the middle and gradually narrows towards both ends.

[0014] As a further preferred embodiment of this utility model, the maximum outer diameter of the middle part of the spiral scraper is 45mm, which gradually decreases to 40mm towards both ends.

[0015] As a further preferred embodiment of this utility model, the spiral scraper blade is capable of axial displacement and free rotation on the central rod, and a guide groove is formed between adjacent spirals.

[0016] As a further preferred embodiment of this utility model, the weight bar is a tungsten steel weight bar, and the spiral outer edge of the spiral scraper is provided with a hard alloy layer.

[0017] Compared with the prior art, the advantages or beneficial effects of the embodiments of this application include at least the following: 1. The spiral scraping assembly consists of a scraping blade guide and a spiral scraping blade, with a variable diameter structure from the middle to both ends of the maximum outer diameter, which reduces the process of frequently changing existing scraping tools with different diameters and sequentially going down into the well for construction, thereby reducing labor intensity, construction costs and time.

[0018] 2. The spiral scraper blades can move axially and rotate freely on the central rod, reducing the contact area when contacting scaled areas. This increases the descaling effect while preventing tools from getting stuck in scale, thus reducing the cost of well workover operations in water injection wells.

[0019] 3. Descaling can be completed simply by lowering the wire rope well test winch, resulting in low construction costs and low labor intensity. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. The drawings are provided for reference and illustration only and are not intended to limit this utility model. Wherein: Figure 1 This is a front view of the mechanical descaling device for the water injection tubing test channel of this utility model; Figure 2 This is a perspective view of the mechanical descaling device for the water injection tubing test channel of this utility model; In the diagram: 1. Guide cone; 2. Lower lock nut; 3. Lower spring; 4. Scraper guide tube; 5. Spiral scraper; 6. Upper spring; 7. Center rod; 8. Upper lock nut; 9. Threaded joint; 10. Weight rod; 11. Rope cap. Detailed Implementation

[0021] In the following description of this utility model, the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not mean that the device must have a specific orientation.

[0022] To make the technical means, creative features, achieved objectives and effects of this utility model easier to understand, the present utility model will be further described below with reference to specific illustrations. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0024] like Figure 1 , Figure 2As shown, the mechanical descaling device for the water injection pipe test channel of this utility model includes, from bottom to top, a guide cone 1, a lower lock nut 2, a lower spring 3, a scraper guide tube 4, a spiral scraper blade 5, an upper spring 6, a center rod 7, an upper lock nut 8, a threaded joint 9, a weight rod 10, and a rope cap 11. The spiral scraper blade 5 is wound around the outer circumference of the scraper guide tube 4, and the two constitute a spiral scraping assembly. The spiral scraper blade 5 is olive-shaped, with a large diameter in the middle and gradually decreasing towards both ends. The maximum outer diameter in the middle is 45mm, gradually decreasing to 40mm towards both ends. This variable diameter structure from the middle to both ends allows for a larger range of pipe diameters, reducing the need for frequent changes to different pipe diameter tools. The spiral outer edge of the spiral scraper blade 5 is provided with a hard alloy layer to extend its service life.

[0025] The scraper guide 4 is fitted onto the central rod 7 with a clearance fit, allowing for axial movement and a certain amount of vertical movement space. The lower spring 3 is fitted onto the lower part of the central rod 7 and located below the scraper guide 4. The lower end of the central rod 7 is threadedly connected to the guide cone 1 and locked by the lower lock nut 2 and cap.

[0026] The upper spring 6 is mounted on the upper part of the central rod 7 and located above the scraper guide 4. The upper end of the central rod 7 is connected to the upper lock nut 8 and the threaded connector 9. The upper lock nut 8 presses down on the threaded connector 9 to lock it. During the descaling process, when the spiral scraper 5 is obstructed, the central rod 7 can move up and down, which allows the stepped surfaces of the upper lock nuts 8 and lower lock nuts 2 at both ends of the central rod 7 to vibrate against the spiral scraper assembly to achieve the descaling effect.

[0027] A weight bar 10 is screwed onto the upper part of the threaded connector 9 to generate sufficient downward scraping force when the tool falls and impacts downward. A rope cap 11 is connected to the upper end of the weight bar 10 for connecting to the lower end of the wire rope.

[0028] This device utilizes the principle of mechanical impact and the characteristic that the spiral scraper 5 installed on the outer periphery of the scraper guide 4 can rotate freely. It is lowered into the water injection well shaft by a winch through a steel wire rope connected to the rope cap 11. When the tool reaches the position where it encounters scale, it is lifted a certain distance and then lowered in a free-falling state. When the first-stage scraper of the spiral scraper 5 contacts the scale position, the spiral scraping assembly stops moving downward. The guide cone 1 and the central rod 7 continue to descend. The step formed by the upper locking nut 8 impacts the upper spring 6. The lower end of the upper spring 6 impacts the spiral scraping assembly downward. The upper spring 6 buffers the impact, playing a certain role in shock absorption and protection, and causing the spiral scraper 5 to rotate. The downward impact process produces a downward rotating scraping effect.

[0029] Then, the center rod 7 is lifted, and the lower lock nut 2 strikes the lower end of the lower spring 3 upwards. The upper end of the lower spring 3 strikes the spiral scraping assembly upwards. The lower spring 3 buffers the impact, providing shock absorption and protection, and also causes the spiral scraper blade 5 to rotate. The upward impact produces an upward rotating scraping effect. Repeat the above operation multiple times to scrape away the scale buildup on the inner wall of the tubing, achieving the descaling effect.

[0030] The guide grooves between the pitches of the spiral scraper blades 5 guide the scraped debris to fall to the bottom of the well along the spiral trajectory. The axially movable scraper blade guide tube 4 is combined with the spiral scraper blades 5 to prevent the tool from getting stuck during the descaling process.

[0031] The weight bar 10 is made of tungsten steel, which provides a large weight in a small volume. It has extremely high hardness and strength, and is not easily deformed or damaged in the harsh working environment downhole. It can also effectively reduce wear during use, extend the service life of the weight bar, and reduce replacement costs.

[0032] The operation process of the mechanical descaling device in the test channel of this water injection tubing is as follows: 1. Pull the wire rope out of the winch, tie a wire rope knot and connect it to the rope cap 11, ensuring that the knot can rotate freely inside the rope cap 11. Connect the weight rod 10, threaded joint 9, upper lock nut 8 and center rod 7 in sequence from top to bottom. Then install the spring 6, spiral scraping assembly and lower spring 3 on the center rod 7. Finally, connect the guide cone 1 and lower lock nut 2 to the lower end of the center rod 7.

[0033] 2. Guided by the guide cone 1, the device passes through the blowout preventer at the wellhead and is lowered into the tubing in the well. It is lowered at the required speed. When it reaches the position where it encounters obstruction due to scaling, the tool is lifted 50-100 meters by the winch. The brake is then released, allowing the tool to fall naturally under gravity at the speed of free fall.

[0034] 3. When the spiral scraper blade 5 contacts the scaled area, it stops. The step above the center rod 7 and the upper spring 6 impact the spiral scraper assembly, generating an impact force downward to clean the scaled area in the tubing channel. The debris generated by scraping falls into the bottom of the well along the hollow guide groove of the spiral scraper blade 5.

[0035] 4. If the cleaning is not completed by flushing, lift the center rod 7 and strike the spiral scraper assembly upwards. Repeat the above operation several times until the scale on the inner wall of the tube column is scraped off.

[0036] The above description is merely a preferred embodiment of the present utility model, showing and describing the basic principles, main features, and advantages of the present utility model. It is not intended to limit the scope of patent protection of the present utility model. Those skilled in the art should understand that the present utility model is not limited to the above embodiments. In addition to the above embodiments, the present utility model may have other implementations without departing from the spirit and scope of the present utility model. Various changes and improvements to the present utility model are also possible. All technical solutions formed by equivalent substitutions or equivalent transformations fall within the scope of protection claimed by the present utility model. The scope of protection claimed by the present utility model is defined by the appended claims and their equivalents. Technical features not described in the present utility model can be implemented by or using existing technology, and will not be elaborated here.

Claims

1. A mechanical descaling device for a water injection tubing test channel, comprising a rope cap (11) connected to the lower end of a steel wire rope, characterized in that, A weighted rod (10) is connected below the rope cap (11). A threaded connector (9) is connected to the lower end of the weighted rod (10). A central rod (7) is connected to the lower end of the threaded connector (9). A scraper guide (4) is fitted around the middle section of the central rod (7). The scraper guide (4) is clearance-fitted with the central rod (7). A spiral scraper (5) is wound around the outer circumference of the scraper guide (4). A guide cone (1) is screwed onto the lower end of the central rod (7).

2. The mechanical descaling device for the water injection tubing test channel according to claim 1, characterized in that: The upper end of the central rod (7) is fitted with an upper spring (6), which is located between the upper end of the scraper guide tube (4) and the bottom of the threaded joint (9).

3. The mechanical descaling device for the water injection tubing test channel according to claim 1, characterized in that: The lower end of the central rod (7) is fitted with a lower spring (3), which is located between the lower end of the scraper guide tube (4) and the top of the guide cone (1).

4. The mechanical descaling device for the water injection tubing test channel according to claim 2, characterized in that: The upper end of the central rod (7) is also screwed with a lock nut (8), the top of the lock nut (8) abuts against the bottom of the threaded joint (9), and the upper spring (6) is located between the upper end of the scraper guide tube (4) and the bottom of the lock nut (8).

5. The mechanical descaling device for the water injection tubing test channel according to claim 3, characterized in that: The lower end of the central rod (7) is also screwed with a lower lock nut (2), the bottom of the lower lock nut (2) is pressed against the top of the guide cone (1), and the lower spring (3) is located between the lower end of the lower spring (3) and the top of the guide cone (1).

6. The mechanical descaling device for the water injection tubing test channel according to claim 1, characterized in that: The spiral scraper blade (5) is olive-shaped with a large diameter in the middle and gradually narrows towards both ends.

7. The mechanical descaling device for the water injection tubing test channel according to claim 6, characterized in that: The spiral scraper (5) has a maximum outer diameter of 45 mm in the middle part and gradually decreases to 40 mm towards both ends.

8. The water injection string test passage mechanical scale removal device of claim 1, wherein: The spiral scraper blade (5) can be axially displaced and freely rotated on the central rod (7), and a guide groove is formed between adjacent spirals.

9. The mechanical descaling device for the water injection tubing test channel according to claim 1, characterized in that: The weight bar (10) is a tungsten steel weight bar, and the spiral outer edge of the spiral scraper (5) is provided with a hard alloy layer.

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