A device for cleaning heavy oil from wellbore.

Abstract

This invention provides a device for cleaning heavy oil from wellbore, comprising: a central pipe connected to the bottom end of a tubing string and multiple scraper groups arranged along the outer periphery of the central pipe. Each scraper group is located at a different height on the outer periphery of the central pipe, and each scraper group includes multiple scrapers evenly arranged on the outer periphery of the central pipe. The projections of all scrapers along the axial direction of the central pipe are staggered and evenly distributed. This invention can effectively prevent large chunks of heavy oil from flowing back and clogging the channel, and can also prevent secondary flow of heavy oil and blowouts.

Description

Technical Field

[0001] This utility model belongs to the field of oilfield development technology, specifically, it relates to a device for cleaning heavy oil in wellbores. Background Technology

[0002] After a wellbore blockage accident occurs in heavy oil wells, if production is to be restored, it is necessary to clean the heavy oil in the wellbore through downhole operations to remove the blockage. Currently, the processes for cleaning heavy oil in wellbores include: (1) hot thin oil dissolution and high-temperature viscosity reduction in coiled tubing, which has the disadvantages of high cost and high risk; (2) segmented hot washing of bare tubing, which has the disadvantages of long construction period and poor effect; (3) rotary pressurized well fluid circulation and crushing of drill bit or grinding shoe, which has the disadvantages of slow advance, long construction period and secondary blockage accident caused by lifting piston. Since drill bit is mainly used to drill through hard and brittle formation minerals and clean obstacles formed by hard and brittle minerals in the wellbore, and grinding shoe is mainly used to grind away hard obstacles formed by artificial materials such as metal in the well, both have a certain effect on treating heavy oil, but the treatment efficiency is low and there are a lot of large pieces of heavy oil left. Moreover, when the tubing is lifted after the treatment is completed, the heavy oil is often back up, causing blockage of the wellbore. Utility Model Content

[0003] One objective of this invention is to provide a device for cleaning heavy oil in wellbore, so as to effectively prevent large pieces of heavy oil from flowing back and blocking the channel, while avoiding secondary flow of heavy oil and overflow blowout.

[0004] According to the present invention, an apparatus for cleaning heavy oil in a wellbore is provided, comprising: a central pipe connected to the bottom end of a tubing string and a plurality of scraper groups arranged along the outer periphery of the central pipe, each scraper group being located at a different height on the outer periphery of the central pipe, and each scraper group comprising: a plurality of scrapers uniformly arranged on the outer periphery of the central pipe, wherein the projections of all the scrapers along the axial direction of the central pipe are staggered and uniformly distributed.

[0005] In a preferred embodiment, the system includes a second scraper group and a first scraper group, wherein the second scraper group is located above the first scraper group.

[0006] In a preferred embodiment, the distance between the first scraper group and the second scraper group along the axis of the central tube is 100 mm.

[0007] In a preferred embodiment, the second scraper group and the first scraper group have the same number of scrapers.

[0008] In a preferred embodiment, both the second scraper group and the first scraper group have three scrapers, and adjacent scrapers in each scraper group are at a 120° angle to each other. The projections of all scrapers along the axis of the central tube are staggered and evenly distributed at a 60° angle.

[0009] In a preferred embodiment, both the first scraper group and the second scraper group are made of quenched steel plates with a thickness of 20 mm, welded to the outer surface of the central tube.

[0010] In a preferred embodiment, the top end of the central tube is provided with an upper connector, which is connected to the bottom end of the tube column.

[0011] In a preferred embodiment, the upper connector is connected to the bottom end of the tubing via a snap-fit.

[0012] In a preferred embodiment, the scrapers of the second scraper group and the first scraper group are configured with a 45° bevel on the side away from the central tube in the radial direction of the central tube to form a sharp cutting edge, and the bevels extend in the same direction on the side away from the central tube.

[0013] In a preferred embodiment, all the scrapers of the first scraper group extend from the bottom port of the central tube along the axial direction of the central tube, and extend inward along the radial direction of the central tube, then extend upward along the axial direction of the central tube, and then extend inward along the radial direction of the central tube to the center of the central tube, so that the bottom port of the central tube forms three nozzles distributed in three directions between the scrapers.

[0014] This utility model has at least the following technical effects:

[0015] According to this utility model, a central tube connected to the bottom end of the tubing string and multiple scraper groups arranged along the outer periphery of the central tube are provided. Each scraper group is located at a different height on the outer periphery of the central tube, and each scraper group includes multiple scrapers evenly arranged on the outer periphery of the central tube. The projections of all scrapers along the axis of the central tube are staggered and evenly distributed, thereby effectively preventing large pieces of heavy oil from returning and blocking the channel by cutting the heavy oil multiple times. At the same time, during the lifting process, the "piston-pulling" effect of suction can be greatly reduced, avoiding secondary return of heavy oil and overflow blowout. Attached Figure Description

[0016] Figure 1 A schematic diagram of the overall structure of an apparatus for cleaning heavy oil in a wellbore according to an embodiment of the present invention is shown.

[0017] Figure 2 Another structural schematic diagram of an apparatus for cleaning heavy oil in a wellbore according to one embodiment of the present invention is shown schematically;

[0018] Figure 3 A bottom view schematic diagram of a device for cleaning heavy oil in a wellbore according to an embodiment of the present invention is shown.

[0019] In this application, all the accompanying drawings are schematic drawings, used only to illustrate the principle of the present invention, and are not drawn to scale. Detailed Implementation

[0020] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0021] In the description of this utility model, it should be understood that the terms "outer," "inner," etc., indicating the orientation or positional relationship are 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 indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this utility model. In this utility model, "a plurality of" means two or more.

[0022] In this utility model, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0023] like Figures 1 to 2 As shown, the device 100 for cleaning heavy oil in wellbore according to this invention includes: a central pipe 2 connected to the bottom end of a tubing string (e.g., tubing); and multiple scraper groups arranged along the outer periphery of the central pipe 2. Each scraper group is located at a different height along the axial direction of the central pipe 2, and each scraper group includes multiple scrapers evenly arranged around the outer periphery of the central pipe 2. The projections of all scrapers along the axial direction of the central pipe 2 are staggered and evenly distributed. For example, the device 100 for cleaning heavy oil in wellbore according to this invention includes: a second scraper group 3 and a first scraper group 4 arranged near the bottom end of the central pipe 2. The second scraper group 3 is located above the first scraper group 4, and both the second scraper group 3 and the first scraper group 4 include multiple scrapers evenly arranged around the outer periphery of the central pipe 2.

[0024] The following is a brief description of the usage process of the device 100 for cleaning heavy oil in wellbore according to this utility model. The device is connected to the bottom of the tubing string and lowered down into the well to the top of the heavy oil. Well fluid is circulated in a positive direction. While the tubing string is rotated clockwise, it is lowered. The scrapers of the first scraper group 4 rotate clockwise and scrape downwards, breaking the highly viscoelastic heavy oil into larger fragments. These fragments are carried upwards by the well fluid from the annulus to the second scraper group 3. The larger heavy oil fragments are further broken into smaller fragments by the scrapers of the second scraper group 3, and then more evenly mixed with the well fluid before returning to the wellhead surface, effectively preventing large pieces of heavy oil from returning and clogging the passage.

[0025] Furthermore, the device 100 for cleaning heavy oil in the wellbore described in this utility model significantly reduces the overall area of ​​the iron structure along the radial direction of the tubing compared to the drill bit shoe. When it is lifted, it can greatly reduce the "piston-pulling" effect of suction, and avoid secondary backflow of heavy oil and overflow blowout.

[0026] In one or more embodiments, an upper connector 1 is provided at the top end of the central tube 2, and the upper connector 1 is connected to the bottom end of the tube column. Optionally, the upper connector 1 is connected to the bottom end of the tube column by a snap-fit. The central tube 2 and the upper connector 1 are integrally formed, and the outer diameter of the central tube 2 is 73 mm and the inner diameter is 50 mm.

[0027] In one or more embodiments, the second scraper group 3 and the first scraper group 4 have the same number of scrapers. Optionally, both the second scraper group 3 and the first scraper group 4 have three scrapers evenly arranged along the outer periphery of the central tube 2, with adjacent scrapers in each scraper group forming a 120° angle, and the projections of all scrapers along the axial direction of the central tube 2 are staggered and evenly distributed at a 60° angle.

[0028] In one or more embodiments, the first scraper group 4 and the second scraper group 3 are both made of quenched steel plates with a thickness of 20 mm welded to the outer surface of the central tube 2.

[0029] like Figure 2 As shown, in one or more embodiments, the scrapers of the second scraper group 3 and the first scraper group 4 are constructed with a 45° bevel on the side of the central tube 2 away from the central tube 2 in the radial direction to form a sharp cutting edge, and the extension direction of each bevel on the side away from the central tube 2 is the same, for example, along the same initial rotation direction after the tube is lowered (i.e., in a clockwise direction). The length of the second scraper group 3 along the axial direction of the central tube 2 is 200 mm, and the length of the first scraper group 4 along the axial direction of the central tube 2 is 240 mm.

[0030] like Figure 3As shown, in one or more embodiments, all scrapers of the first scraper group 4 extend 25 mm from the bottom port of the central tube 2 along the axial direction of the central tube 2, extend inward along the radial direction of the central tube 2, then extend upward 90 mm along the axial direction of the central tube 2, and then extend inward along the radial direction of the central tube 2 to the center of the central tube 2, so that the bottom port of the central tube 2 forms three nozzles distributed in three directions between the scrapers to increase the flow rate and thereby enhance the ability to flush and backflow the heavy oil.

[0031] In one or more embodiments, the first scraper group 4 and the second scraper group 3 are spaced 100 mm apart along the axis of the central tube 2.

[0032] In one or more embodiments, for sleeves of different sizes, the first scraper group 4 and the second scraper group 3 extend beyond the outer surface of the central tube 2 in the radial direction.

[0033] Although the present invention has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An apparatus for cleaning a wellbore of heavy oil, comprising: include: A central tube connected to the bottom end of the tubing column and multiple scraper groups arranged along the outer periphery of the central tube, each scraper group being located at a different height on the outer periphery of the central tube, and each scraper group comprising: multiple scrapers uniformly arranged on the outer periphery of the central tube, with the projections of all scrapers along the axial direction of the central tube being staggered and evenly distributed.

2. The apparatus for cleaning heavy oil from a wellbore of claim 1, wherein, include: A second scraper group and a first scraper group, wherein the second scraper group is located above the first scraper group.

3. The apparatus for cleaning heavy oil from a wellbore of claim 2, wherein, The distance between the first scraper group and the second scraper group along the axis of the central tube is 100 mm.

4. The apparatus for cleaning heavy oil from a wellbore of claim 2, wherein, The second scraper group and the first scraper group have the same number of scrapers.

5. The apparatus for cleaning heavy oil from a wellbore of claim 3, wherein, Both the second scraper group and the first scraper group have three scrapers, and the adjacent scrapers in each scraper group are at a 120° angle to each other. The projections of all scrapers along the axis of the central tube are staggered and evenly distributed at a 60° angle.

6. The apparatus for cleaning heavy oil from a wellbore of any one of claims 2 to 5, wherein, Both the first scraper assembly and the second scraper assembly are made of quenched steel plates with a thickness of 20mm, welded to the outer surface of the central tube.

7. The apparatus for cleaning heavy oil from a wellbore of claim 1 or 2, wherein, The top end of the central tube is provided with an upper connector, which is connected to the bottom end of the tube column.

8. The apparatus for cleaning heavy oil from a wellbore of claim 7, wherein, The upper connector is connected to the bottom end of the tubing via a snap fastener.

9. The apparatus for cleaning heavy oil from a wellbore of claim 2, wherein, The scrapers of the second scraper group and the first scraper group are constructed with a 45° bevel on the side away from the central tube in the radial direction of the central tube to form a sharp cutting edge, and the bevels extend in the same direction on the side away from the central tube.

10. The apparatus for cleaning heavy oil from a wellbore of claim 2, wherein, All the scrapers of the first scraper group extend from the bottom port of the central tube along the axial direction of the central tube, and extend inward along the radial direction of the central tube, then extend upward along the axial direction of the central tube, and then extend inward along the radial direction of the central tube to the center of the central tube, so that the bottom port of the central tube forms three nozzles distributed in three directions between the scrapers.

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