Scraper

Abstract

The invention provides a scraper which comprises a center pipe, a first fixing part, a first piston, a second piston, a scraper sleeve, one or more scrapers and a piston bush, the one or more scrapers abut against the interior of the scraper sleeve, the first piston is fixedly connected with the scraper sleeve, the scraper sleeve is fixedly connected through the first fixing part, and the second piston is fixedly connected with the piston bush through the second fixing part. The first piston and the second piston are both located between the piston sleeve and the center pipe, and a closed air cavity is formed among the first piston, the second piston, the inner wall of the piston sleeve and the outer wall of the center pipe, so that the first piston has the trend of moving in the axis direction of the center pipe in the well descending process of the scraper. After the first piston cuts off the first fixing piece through the movement trend, the first piston can drive the scraper sleeve to move in the axis direction of the center pipe so that the scraper can be popped out. The situation that the drift diameter of a casing pipe in a well drilling well cannot be matched with the outer diameter of a scraper usually can be avoided, and the setting success rate of the bridge plug is increased.

Description

Technical Field

[0001] The invention relates to the technical field of drilling equipment, in particular to a scraper. Background Art

[0002] Before side drilling with casing windows in the well, it is necessary to drive a cement plug below the side drilling point to seal the lower well section. Before driving the cement plug, it is necessary to first set a bridge plug in the lower part to ensure the success rate and quality of the cement plug. The pipe scraping process is an important process to ensure the success rate of the bridge plug setting. The pipe scraping is usually achieved by the scraper blade.

[0003] In actual working conditions, the diameter of the inner casing of the drilling well is usually not compatible with the size of the outer diameter of the scraper. If the scraper blade of the scraper is in the extended state and enters the drilling well, the scraper is often unable to pass through the wellhead spool due to its too large outer diameter, and it is also impossible to perform pipe scraping operations on the pre-sealed bridge plug section, resulting in a low success rate of bridge plug sealing. In addition, for some scrapers, when the blade is in the open state, although they can enter and pass through the outer diameter of the wellhead spool, the outer diameter of the scraper after the blade is opened is too small, which also causes the scraper to fail to scrape the pipe. Summary of the invention

[0004] One object of the present invention is to provide a scraper, whose scraper blade is in a retracted state before entering the well. After entering the well to a certain depth, it can pop out to scrape the casing, thereby avoiding the situation that the diameter of the casing inside the drilling is usually not compatible with the size of the scraper outer diameter, facilitating efficient scraping operations on the pre-sealed bridge plug well section and improving the success rate of bridge plug sealing.

[0005] According to the present invention, a scraper is provided, comprising a center tube, a first fixing member, a first piston, a second piston, a scraper sleeve, one or more scrapers and a piston sleeve, wherein one or more scrapers are abutted against the interior of the scraper sleeve, the first piston is fixedly connected to the scraper sleeve, the first fixing member fixes the scraper sleeve, the first piston and the second piston are both located between the piston sleeve and the center tube, and a closed air cavity is formed between the first piston, the second piston, the inner wall of the piston sleeve and the outer wall of the center tube, so that when the scraper is lowered into the well, the first piston has a tendency to move along the axis of the center tube, and after the first piston shears off the first fixing member through the movement tendency, the first piston can drive the scraper sleeve to move along the axis of the center tube to make the scraper pop out.

[0006] In a preferred embodiment, the scraper further comprises an elastic member and a scraper blade holder, wherein a first end of the elastic member is connected to the scraper blade holder, and a second end of the elastic member is connected to the scraper blade.

[0007] In a preferred embodiment, the first piston can be engaged with the central tube during movement along the axial direction of the central tube.

[0008] In a preferred embodiment, the first piston is provided with a through hole in a direction perpendicular to the central tube, an elastic portion and a second fixing member connected to the elastic portion are provided in the through hole, and a groove is provided on the outer wall of the central tube, and the second fixing member can bounce into the groove when passing through the groove.

[0009] In a preferred embodiment, the scraper further comprises a third fixing member, and the third fixing member fixes the second piston.

[0010] In a preferred embodiment, the second piston has a tendency to move along the axis of the central tube under the pressure of the liquid column. After the second piston cuts off the third fixing member through the movement tendency, the air cavity can be eliminated by moving in the piston sleeve.

[0011] In a preferred embodiment, a cavity formed by the second piston, a sealing portion and a portion of the outer surface of the center tube is provided on the side of the second piston away from the air cavity. The contact portion between the second piston and the sealing portion is sealed by a first seal, and the bottom of the second piston and the outer surface of the center tube are sealed by a second seal. On the path of the second piston moving toward the first piston, the diameter of the center tube becomes smaller. When the second piston moves to the diameter-changing position of the center tube, the second piston disengages from the first seal, so that the air cavity and the cavity are connected through the gap between the top of the second piston and the piston sleeve.

[0012] In a preferred embodiment, the force applied by the first piston to the first fixing member is greater than the force applied by the second piston to the third fixing member.

[0013] In a preferred embodiment, the first piston can shear off the second fixing member under the action of external pressure, and drive the scraper sleeve to move along the axial direction of the central tube toward the scraper seat, so that the scraper sleeve can accommodate the scraper into the scraper seat.

[0014] In a preferred embodiment, both ends of the scraper blade are respectively configured as first inclined surfaces, and the end of the scraper blade cover is configured as a second inclined surface, and the second inclined surface can be fitted with the first inclined surface.

[0015] The present invention has one or more scrapers abutting against the interior of the scraper sleeve, the first piston is fixedly connected to the scraper sleeve and the first fixing piece fixes the scraper sleeve, the first piston and the second piston are both located between the piston sleeve and the center tube, and a closed air cavity is formed between the first piston, the second piston, the inner wall of the piston sleeve and the outer wall of the center tube, so that when the scraper is lowered into the well, the first piston has a tendency to move along the axis of the center tube, and after the first piston cuts off the first fixing piece through the movement tendency, the first piston can drive the scraper sleeve to move along the axis of the center tube, so that the scraper pops out, and can The scraper blade of the scraper described in the present invention is in a retracted state before entering the well, thereby reducing the outer diameter of the scraper to facilitate entering the well. After the scraper is lowered into the well to a certain depth, the first piston shears the first fixing part through the movement trend under the action of the pressure difference on both sides, and moves along the axial direction of the central pipe toward the second piston and drives the scraper blade sleeve to move, so that the scraper blade can pop out to scrape the casing, thereby avoiding the diameter of the casing inside the drilling usually not being able to adapt to the size of the outer diameter of the scraper, facilitating efficient scraping operations on the pre-sealed bridge plug well section, and improving the success rate of bridge plug sealing.

[0016] The present invention provides a through hole in the first piston along a direction perpendicular to the center tube, an elastic part and a second fixing part connected to the elastic part in the through hole, and a groove on the outer wall of the center tube. During the movement of the first piston along the axial direction of the center tube, the end of the second fixing part slides in contact with the outer wall of the center tube. When the second fixing part passes through the groove, the second fixing part can bounce into the groove under the elastic force of the elastic part, thereby preventing the first piston from moving in the opposite direction under the external force during the movement toward the second piston, causing the scraper sleeve to retract the scraper into the scraper seat, thereby avoiding a reduction in the scraper operation efficiency.

[0017] The present invention fixes the second piston with a third fixing member, thereby preventing the first piston from colliding with the second piston when the first piston moves toward the first joint along the axial direction of the central tube, thereby ensuring that a certain distance can be maintained between the opposite end faces of the first piston and the second piston.

[0018] The present invention enables the first piston to shear off the second fixing part under the action of external pressure, and drives the scraper sleeve to move along the axial direction of the central pipe toward the scraper seat, so that the scraper sleeve can accommodate the scraper in the scraper seat. After the scraping construction is completed, the scraper can be retracted again by pressing to reduce the outer diameter of the scraper, thereby facilitating the scraper to be lifted out of the well.

[0019] The present invention configures the two ends of the scraper blade as first inclined surfaces respectively, and the end of the scraper cover as a second inclined surface. The second inclined surface can fit with the first inclined surface. The inclined surfaces cooperate with each other, so that the scraper cover can accommodate the scraper into the scraper seat, thereby improving the scraper recovery efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The overall structure of the scraper according to the present invention is schematically shown;

[0021] Figure 2 A partial enlarged view of a scraper according to the present invention is schematically shown;

[0022] Figure 3 The schematic diagram of the structure after the second piston moves is shown schematically.

[0023] In the present application, all drawings are schematic drawings, which are only used to illustrate the principles of the present invention and are not drawn according to the actual scale. DETAILED DESCRIPTION

[0024] like Figure 1 as well as Figure 2 As shown, the scraper 100 of the present invention comprises: a central tube 2, a first fixing member 3, a first piston 6, a second piston 4, a scraper sleeve 9, one or more scrapers 8, a piston sleeve 5, a first joint 1 and a second joint 11, wherein the first joint 1 and the second joint 11 are respectively fixedly arranged at the first end and the second end of the central tube 2, and the first joint 1 and the second joint 11 are connected to the central tube 2 by threads and sealed by O-rings. One or more scrapers 8 are abutted against the interior of the scraper sleeve 9, and the first piston 6 is fixedly connected to the scraper sleeve 9. For example, the first piston 6 is fixedly connected to the scraper sleeve 9 by a threaded member. The scraper sleeve 9 can move along the axial direction of the central tube 2 under the action of the first piston 6. When the scraper sleeve 9 moves and is no longer abutted against one or more scrapers 8 inside it, the scrapers 8 can pop out and scrape the pipe in the well section.

[0025] The first fixing part 3 fixes the scraper sleeve 9 to the scraper limiting ring (not shown in the figure). The first fixing part 3 can be a shear pin. The first piston 6 and the second piston 4 are both located between the piston sleeve 5 and the center tube 2 and the two are arranged opposite to each other and separated by a certain distance. The first piston 6 and the second piston 4 can both move along the axial direction of the center tube 2. The contact surfaces between the first piston 6, the second piston 4, the piston sleeve 5 and the central tube 2 are all sealed by O-rings so that a closed air cavity s is formed between the two opposite end surfaces of the first piston 6 and the second piston 4, a portion of the inner wall of the piston sleeve 5 and a portion of the outer wall of the central tube 2. During the process of the scraper 100 described in the present invention entering the well for operation, there is a pressure difference on both sides of the first piston 6, that is, the pressure on the side of the first piston 6 close to the scraper sleeve 9 is the pressure applied by the liquid column in the well, and there is a pressure difference between the pressure on this side and the pressure on the side of the first piston 6 in contact with the air cavity s, and the pressure difference gradually increases with the increase of the depth of the well, so that the first piston 6 has a tendency to move toward the second piston 4 along the axial direction of the central tube 2. The first piston 6 can apply a shear force to the first fixing member 3 through the movement tendency, and after the first fixing member 3 is cut off, the first piston 6 can move toward the second piston 4 along the axial direction of the central tube 2 and drive the scraper sleeve 9 to move, so that the scraper 8 pops out.

[0026] In the present invention, one or more scrapers 8 are abutted against the interior of the scraper sleeve 9, the first piston 6 is fixedly connected to the scraper sleeve 9, the first fixing member 3 fixes the scraper sleeve 9, the first piston 6 and the second piston 4 are both located between the piston sleeve 5 and the central tube 2, and a closed air chamber s is formed between the first piston 6, the second piston 4, the inner wall of the piston sleeve 5 and the outer wall of the central tube 2, so that when the scraper 100 is lowered into the well, the first piston 6 has a tendency to move along the axial direction of the central tube 2, and after the first piston 6 cuts off the first fixing member 3 through the movement tendency, the first piston 6 can drive the scraper sleeve 9 to move along the axial direction of the central tube 2, so that the scraper 8 can be elastically moved. The scraper 8 of the scraper 100 described in the present invention can be in a retracted state before entering the well, thereby reducing the outer diameter of the scraper 100 to facilitate entering the well. After the scraper 100 is lowered into the well to a certain depth, the first piston 6, under the action of the pressure difference on both sides, shears the first fixing part 3 through the movement trend, and moves along the axial direction of the central pipe 2 toward the second piston 4 and drives the scraper sleeve 9 to move, so that the scraper 8 can pop out to scrape the casing, thereby avoiding the diameter of the casing inside the drilling usually not being able to adapt to the size of the outer diameter of the scraper, facilitating efficient scraping operations on the pre-sealed bridge plug well section, and improving the success rate of bridge plug sealing.

[0027] In one or more embodiments, the scraper 100 described in the present invention also includes an elastic member 7 and a scraper seat 71. The scraper seat 71 is fixedly arranged on the outer wall of the central tube 2. The first end of the elastic member 7 is connected to the scraper seat 71. The scraper seat 71 is used to accommodate one or more scrapers 8. The second end of the elastic member 7 is connected to the scraper 8. The elastic member 7 is in a compressed state between the scraper seat 71 and the scraper 8.

[0028] The present invention connects the first end of the elastic member 7 to the scraper seat 71 and the second end of the elastic member 7 to the scraper 8. When the scraper sleeve 9 moves under the action of the first piston 6 and is no longer in contact with one or more scrapers 8 inside it, the scraper 8 can pop out under the elastic force of the elastic member 7 and perform scraping operations in the well section.

[0029] In one or more embodiments, the first piston 6 can be engaged with the central tube 2 during movement along the axial direction of the central tube 2 .

[0030] The present invention enables the first piston 6 to be clamped to the central tube 2 during the movement along the axial direction of the central tube 2, thereby preventing the first piston 6 from moving in the opposite direction under the external force during the movement toward the second piston 4, causing the scraper sleeve 9 to retract the scraper 8 into the scraper seat 71.

[0031] In one or more embodiments, the first piston 6 is provided with a through hole (not shown) in a direction perpendicular to the center tube 2, an elastic portion 61 and a second fixing member 62 connected to the elastic portion 61 are provided in the through hole, a groove 21 is provided on the outer wall of the center tube 2, and the second fixing member 62 can bounce into the groove 21 when passing through the groove 21. Optionally, the groove 21 is provided close to the end face of the first piston 6.

[0032] The present invention provides a through hole in the first piston 6 along the direction perpendicular to the central tube 2, an elastic part 61 and a second fixing part 62 connected to the elastic part 61 are provided in the through hole, and a groove 21 is provided on the outer wall of the central tube 2. When the first piston 6 moves along the axial direction of the central tube 2, the end of the second fixing part 62 slides and contacts with the outer wall of the central tube 2. When the second fixing part 62 passes through the groove 21, the second fixing part 62 can be rebounded into the groove 21 under the elastic force of the elastic part 61, thereby preventing the first piston 6 from moving in the opposite direction under the external force when moving toward the second piston 4, causing the scraper cover 9 to retract the scraper 8 into the scraper seat 71, thereby avoiding reducing the scraper operation efficiency. The second fixing part 62 can be a shear pin.

[0033] In one or more embodiments, the scraper 100 of the present invention further includes a third fixing member 63, which is used to fix the second piston 4 to the central tube 2. The third fixing member 63 may be a shear pin, and the second piston 4 has a tendency to move along the axial direction of the central tube 2 under the action of the liquid column pressure. Since the pressure on the side of the second piston 4 away from the air cavity s is the pressure applied by the liquid column in the well, there is a pressure difference between the pressure on this side and the pressure on the side of the second piston 4 in contact with the air cavity s, and the pressure difference gradually increases with the increase in the depth of the well, so that the second piston 4 has a tendency to move along the axial direction of the central tube 2 toward the first piston 6. After the second piston 4 shears off the third fixing member 63 through the movement tendency, it can eliminate the air cavity s by moving along the axial direction of the central tube 2 in the piston sleeve 5.

[0034] The present invention fixes the second piston 4 with the third fixing member 63, thereby preventing the first piston 6 from colliding with the second piston 4 when the first piston 6 moves toward the first joint 1 along the axial direction of the center tube 2, thereby ensuring that a certain distance can be maintained between the opposite end faces of the first piston 6 and the second piston 4.

[0035] The present invention enables the second piston 4 to shear the third fixing piece 63 through the movement tendency, and then eliminate the air cavity s in the piston sleeve 5 by moving along the axial direction of the central tube 2. After the air cavity s is eliminated, the scraper 100 described in the present invention can go down to a deeper position in the well without damaging the first piston 6 and the second piston 4. It can also facilitate the subsequent injection of water into the air cavity s to increase the pressure, and enable the first piston 6 to move toward the direction close to the piston seat 71 under the action of pressure, so as to facilitate the retraction of the scraper 8 to the piston seat 71.

[0036] like Figure 3 As shown, in one or more embodiments, a cavity p is provided on the side of the second piston 4 away from the air cavity s, and the cavity p is surrounded by the second piston 4, the sealing portion 101 and the outer surface of a part of the center tube 2. The contact portion between the second piston 4 and the sealing portion 101 is sealed by a first seal c, and the bottom of the second piston 4 and the outer surface of the center tube 2 are sealed by a second seal d. The cavity p is connected with the interior of the center tube 2 through an internal channel 22. On the path where the second piston 4 moves toward the first piston 6, the diameter of the center tube 2 becomes smaller, that is, the diameter of the center tube 2 at D1 is larger than the diameter at D2. When the second piston 4 moves along the axial direction of the center tube 2 to the second diameter D2 position where the center tube 2 changes diameter, the second piston 4 disengages from the first seal c, so that the air cavity s is connected with the cavity p through the gap between the top of the second piston 4 and the piston sleeve 5, thereby destroying the closed air cavity s.

[0037] In one or more embodiments, the cross-sectional area of ​​the first piston 6 is greater than the cross-sectional area of ​​the second piston 4. Under the pressure of the liquid column, the shear force applied by the first piston 6 to the first fixing member 3 is greater than the shear force applied by the second piston 4 to the third fixing member 63.

[0038] The shear force is greater than the shear force applied by the second piston 4 to the third fixing member 63, so that the first fixing member 3 can be sheared off by the first piston 6 first and the first piston 6 can move a certain distance along the axial direction of the central pipe 2 and be fixed before the third fixing member 63 can be sheared off by the second piston 4, thereby ensuring that after the scraper 100 described in the present invention descends to a certain depth in the well, the scraper blade 8 can be released first for scraping pipe operation, and in the process of continuing to descend in the well, the air cavity s can be broken to protect the first piston 6 and the second piston 4.

[0039] In one or more embodiments, the interior of the center pipe 2 described in the present invention is connected to the interior of the air cavity s through an internal pipe 22 perpendicular to the axis of the center pipe 2. Water can be pumped into the interior of the center pipe 2 and into the air cavity s outside the well through a pump and a pipe to seal and pressurize the interior of the scraper 100. The first piston 6 can cut off the second fixing part 62 under the action of the external water pressure, and drive the scraper sleeve 9 to move along the axial direction of the center pipe 2 toward the direction close to the scraper 8. Under the squeezing of the piston force, the scraper sleeve 9 can accommodate the scraper 8 in the scraper seat 71.

[0040] The present invention enables the first piston 6 to shear off the second fixing piece 62 under the action of external pressure, and drives the scraper sleeve 9 to move along the axial direction of the central pipe 2 toward the scraper seat 71, so that the scraper sleeve 9 can accommodate the scraper 8 into the scraper seat 71. After the scraping construction is completed, the scraper 8 can be retracted again by pressing to reduce the outer diameter of the scraper 100, thereby facilitating the scraper 100 to be lifted out of the well.

[0041] In one or more embodiments, both ends of the scraper blade 8 are respectively configured as first inclined surfaces, and the end of the scraper blade cover 9 is configured as a second inclined surface, and the second inclined surface can be fitted with the first inclined surface.

[0042] The present invention configures the two ends of the scraper blade 8 as first inclined surfaces respectively, and the end of the scraper cover 9 as a second inclined surface. The second inclined surface can fit together with the first inclined surface. The inclined surfaces cooperate with each other, so that the scraper cover 9 can accommodate the scraper blade 8 in the scraper seat 71, thereby improving the recovery efficiency of the scraper blade 8.

[0043] In one or more embodiments, the scraper 100 described in the present invention includes two scraping components symmetrically arranged along the axial direction of the central tube 2, each scraping component includes a first fixing member 3, a first piston 6, a second piston 4, a scraper sleeve 9, one or more scrapers 8, a piston sleeve 5 and an elastic member 7.

[0044] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. 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. A scraper, comprising: A central tube, a first fixing member, a first piston, a second piston, a scraper sleeve, one or more scrapers and a piston sleeve, wherein the scraper sleeve is abutted against one or more scrapers, The first piston is fixedly connected to the scraper sleeve, and the first fixing member fixes the scraper sleeve. The first piston and the second piston are both located between the piston sleeve and the central tube, and a closed air cavity is formed between the first piston, the second piston, the inner wall of the piston sleeve and the outer wall of the central tube, so that when the scraper is lowered into the well, the first piston has a tendency to move along the axial direction of the central tube. After the first piston cuts off the first fixing member through the movement trend, the first piston can drive the scraper cover to move along the axis direction of the central tube, so that the scraper pops out.

2. The scraper according to claim 1, characterized in that: The scraper also includes an elastic member and a scraper seat, wherein a first end of the elastic member is connected to the scraper seat, and a second end of the elastic member is connected to the scraper.

3. The scraper according to claim 2, characterized in that: The first piston can be engaged with the central tube during movement along the axial direction of the central tube.

4. The scraper according to claim 3, characterized in that: The first piston is provided with a through hole in a direction perpendicular to the central tube, an elastic part and a second fixing member connected to the elastic part are provided in the through hole, a groove is provided on the outer wall of the central tube, and the second fixing member can bounce into the groove when passing through the groove.

5. The scraper according to claim 1, characterized in that: The scraper further includes a third fixing member, and the third fixing member fixes the second piston.

6. The scraper according to claim 5, characterized in that: The second piston has a tendency to move along the axis direction of the central tube under the action of the liquid column pressure. After the second piston cuts off the third fixing member through the movement tendency, the air cavity can be eliminated by moving in the piston sleeve.

7. The scraper according to claim 6, characterized in that: A cavity formed by the second piston, a sealing portion and a portion of the outer surface of the center tube is provided on the side of the second piston away from the air cavity. The contact portion between the second piston and the sealing portion is sealed by a first seal, and the bottom of the second piston and the outer surface of the center tube are sealed by a second seal. On the path of the second piston moving toward the first piston, the diameter of the center tube becomes smaller. When the second piston moves to the diameter-changing position of the center tube, the second piston disengages from the first seal, so that the air cavity and the cavity are connected through the gap between the top of the second piston and the piston sleeve.

8. The scraper according to claim 5, characterized in that: The force applied by the first piston to the first fixing member is greater than the force applied by the second piston to the third fixing member.

9. The scraper according to claim 4, characterized in that: The first piston can shear off the second fixing member under the action of external pressure, and drive the scraper sleeve to move along the axial direction of the central tube toward the scraper seat, so that the scraper sleeve can accommodate the scraper into the scraper seat.

10. The scraper according to claim 9, characterized in that Both ends of the scraper blade are respectively configured as first inclined surfaces, and the end of the scraper blade cover is configured as a second inclined surface, and the second inclined surface can be fitted with the first inclined surface.

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