1. An expansion string, comprising:

the expansion cone is provided with a first through hole which is axially communicated;

the pressure relief device comprises an upper joint, a sliding sleeve and an adjusting disc, wherein the upper joint is connected to the lower part of the expansion cone, the upper joint is provided with a second through hole communicated with the first through hole, a nozzle is arranged on the side wall of the upper joint, and the lower end of the upper joint is connected with a plug; the sliding sleeve is movably arranged in the second through hole, the lower end of the sliding sleeve is connected with a spring, the lower end of the spring is connected with the plug, and a nozzle capable of being communicated with the nozzle is arranged on the side wall of the sliding sleeve; the adjusting disk is arranged in the sliding sleeve, a gap is formed between the adjusting disk and the sliding sleeve, and the adjusting disk is connected with the sliding sleeve through a connecting piece.

2. The expansion string of claim 1,

the connecting piece is the connecting rod, the first end of connecting rod with the sliding sleeve meets, the second end of connecting rod with the adjustment disk meets.

3. The expansion string of claim 2,

be equipped with first screw hole on the lateral wall of sliding sleeve, the first end of connecting rod is equipped with first external screw thread, through first external screw thread with the screw-thread fit of first screw hole, the connecting rod with the sliding sleeve meets.

4. The expansion string of claim 2,

the bottom surface of adjusting disk is equipped with the second screw hole, the second end of connecting rod is equipped with the lug, the outer peripheral face of lug is equipped with the second external screw thread, through the second external screw thread with the screw-thread fit of second screw hole, the connecting rod with the adjusting disk meets.

5. The expansion string of claim 2,

the first end of connecting rod with sliding sleeve welded connection, the second end of connecting rod with adjusting disk welded connection.

6. The expansion string of claim 1,

the connecting piece for connect in bead on the outer peripheral face of adjusting disk, the internal surface of sliding sleeve is equipped with the draw-in groove, through the bead with the joint cooperation of draw-in groove, the adjusting disk with the sliding sleeve meets.

7. The expansion string of claim 1,

the upper surface of the plug is provided with a containing groove, and the lower end of the spring is connected with the bottom of the containing groove.

8. The expansion string of claim 1,

the gap is greater than or equal to 2 mm.

9. Expansion string according to any of claims 1 to 8,

the cross section of the adjusting disc is circular, oval or polygonal.

10. The expansion string of claim 9,

the upper surface of the adjusting disc is provided with pits.

Background

At present, in the field of expansion of screen pipes or casing pipes in downhole operation of oil and gas fields, an expansion pipe column generally adopts a circulating pressurization design with matching of a nozzle and a pump truck, the pump truck is pressurized at a large displacement to generate a throttling pressure difference, and an expansion cone generates radial expansion to meet the requirements of site construction. After the pump is stopped and the inner liquid column and the outer liquid column of the pipe column are balanced, the outer diameter of the expansion cone returns to the normal size and can cross the reducing position.

However, the nozzles used in the conventional expansion string are designed to have a fixed size, and the size cannot be changed after the expansion string is lowered to the bottom of the well. The nozzle is generally 7mm-12mm, the size of the nozzle is too small to be beneficial to the balance of the internal pressure and the external pressure of the pipe column, particularly a leakage well, the height difference of the internal liquid level and the external liquid level of the pipe column is large, and long time is needed to realize the pressure balance. If the pressure is not balanced, the outer diameter of the expansion cone cannot retract to the normal size, and the result of pipe column clamping can be caused. When the size of the nozzle is overlarge, the required displacement of the pump truck is overlarge, the pump truck cannot meet the construction requirement, and more polluted liquid returns from the well, which is not beneficial to environmental protection.

Disclosure of Invention

The invention aims to provide an expansion pipe column capable of automatically adjusting the communication area of a nozzle.

To achieve the above object, the present invention provides an expansion string comprising:

the expansion cone is provided with a first through hole which is axially communicated;

the pressure relief device comprises an upper joint, a sliding sleeve and an adjusting disc, wherein the upper joint is connected to the lower part of the expansion cone, the upper joint is provided with a second through hole communicated with the first through hole, a nozzle is arranged on the side wall of the upper joint, and the lower end of the upper joint is connected with a plug; the sliding sleeve is movably arranged in the second through hole, the lower end of the sliding sleeve is connected with a spring, the lower end of the spring is connected with the plug, and a nozzle capable of being communicated with the nozzle is arranged on the side wall of the sliding sleeve; the adjusting disk is arranged in the sliding sleeve, a gap is formed between the adjusting disk and the sliding sleeve, and the adjusting disk is connected with the sliding sleeve through a connecting piece.

The expansion pipe column as described above, wherein the connecting member is a connecting rod, a first end of the connecting rod is connected to the sliding sleeve, and a second end of the connecting rod is connected to the adjusting disk.

The expansion pipe column as described above, wherein the side wall of the sliding sleeve is provided with a first threaded hole, the first end of the connecting rod is provided with a first external thread, and the connecting rod is connected with the sliding sleeve through the threaded fit of the first external thread and the first threaded hole.

The expansion pipe column as described above, wherein the bottom surface of the adjusting plate is provided with a second threaded hole, the second end of the connecting rod is provided with a projection, the outer circumferential surface of the projection is provided with a second external thread, and the connecting rod is connected with the adjusting plate through the threaded fit of the second external thread and the second threaded hole.

The expansion pipe column as described above, wherein the first end of the connecting rod is welded to the sliding sleeve, and the second end of the connecting rod is welded to the adjustment plate.

The expansion pipe column as described above, wherein the connecting member is a rib connected to the outer peripheral surface of the adjusting plate, the inner surface of the sliding sleeve is provided with a groove, and the adjusting plate is connected to the sliding sleeve by the engagement fit of the rib and the groove.

The expansion pipe column as described above, wherein the upper surface of the plug is provided with a receiving groove, and the lower end of the spring is connected to the bottom of the receiving groove.

The expansion string of the above, wherein the clearance is greater than or equal to 2 mm.

The expansion string as described above, wherein the adjustment disc has a circular, elliptical or polygonal cross-section.

The expansion string as described above, wherein the upper surface of the adjustment disc is provided with a dimple.

Compared with the prior art, the invention has the following advantages:

according to the expansion pipe column, the pressure relief device is arranged, so that the communication area of the nozzle can be automatically adjusted, the expansion pipe column can be quickly expanded, the internal pressure and the external pressure of the expansion pipe column can be quickly balanced, the return of polluted liquid is less, and the environment is protected.

Drawings

The drawings are only for purposes of illustrating and explaining the present invention and are not to be construed as limiting the scope of the present invention. Wherein:

FIG. 1 is a schematic representation of the construction of an expansion string of the present invention;

FIG. 2 is a schematic illustration of a pressure relief assembly in the expansion string of FIG. 1;

FIG. 3 is a schematic cross-sectional view taken along line A-A of FIG. 2;

FIG. 4 is a first cross-sectional view of the adjustment disk;

FIG. 5 is a second cross-sectional view of the adjustment disk;

fig. 6 is a schematic diagram of the construction of an expansion cone in the expansion string of fig. 1.

The reference numbers illustrate:

100. expanding a cone; 110. a first through hole;

200. a pressure relief device;

210. an upper joint; 211. a second through hole; 212. a nozzle;

220. a sliding sleeve; 221. a spout; 222. a first threaded hole;

230. an adjusting disk; 231. a second threaded hole; 232. a pit;

240. plugging with a thread; 241. a containing groove;

250. a spring;

260. a connecting member; 261. a bump;

300. a gap.

Detailed Description

In order to clearly understand the technical solution, the purpose and the effect of the present invention, a detailed description of the present invention will be described with reference to the accompanying drawings. Where adjective or adverbial modifiers "upper" and "lower", "inner" and "outer" are used merely to facilitate relative reference between groups of terms, and do not describe any particular directional limitation on the modified terms. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, whereby a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of such features.

As shown in fig. 1, the present invention provides an expansion string suitable for an oil well with serious leakage and a large pressure difference between the inside and the outside of the string, the expansion string comprises an expansion cone 100 and a pressure relief device 200, wherein:

as shown in fig. 6, the expansion cone 100 is provided with a first through hole 110 that is axially through, that is, the first through hole 110 communicates the upper end surface and the lower end surface of the expansion cone 100, and the specific structure and the working principle of the expansion cone 100 are the prior art and are not described herein again;

as shown in fig. 2 and 3, the pressure relief device 200 includes an upper joint 210, a sliding sleeve 220, and an adjustment disc 230, wherein:

the upper joint 210 is connected to the lower part of the expansion cone 100, the upper joint 210 is provided with a second through hole 211 communicated with the first through hole 110, the side wall of the upper joint 210 is provided with a nozzle 212, the lower end of the upper joint 210 is connected with a screwed plug 240, specifically, the upper joint 210 is columnar, the second through hole 211 is arranged along the axial direction of the upper joint 210, namely, the second through hole 211 is communicated with the upper end surface and the lower end surface of the upper joint 210, the first end of the nozzle 212 is communicated with the second through hole 211, the second end of the nozzle 212 is communicated with the outside of the upper joint 210, the upper part of the upper joint 210 is sleeved on the lower part of the expansion cone 100 and is screwed with the expansion cone 100, the screwed plug 240 is screwed on the lower end of the upper joint 210, and the lower end of the second through hole 211 is blocked by the screwed plug 240, so that liquid can only be discharged through the nozzle 212;

the sliding sleeve 220 can be movably arranged in the second through hole 211, specifically, the outer diameter of the sliding sleeve 220 is slightly smaller than the aperture of the second through hole 211, the sliding sleeve 220 can move back and forth between the lower end face of the expansion cone 100 and the upper end face of the plug 240, the lower end of the sliding sleeve 220 is connected with the spring 250, the lower end of the spring 250 is connected with the plug 240, when the sliding sleeve 220 moves towards the plug 240 under the action of external force, the spring 250 can be squeezed to generate elastic force, when the sliding sleeve 220 loses the external force, the sliding sleeve 220 can reset under the action of the elastic force of the spring 250, the side wall of the sliding sleeve 220 is provided with a nozzle 221 which can be communicated with the nozzle 212, the size of the nozzle 221 is matched with the size of the nozzle 212, and when the sliding sleeve 220 is located at an initial position, the nozzle 221 and the nozzle 212 are arranged right opposite to each other, at this time, the communication area of the nozzle 212 is the largest, when the sliding sleeve 220 moves relative to the upper joint 210, the side wall of the sliding sleeve 220 can cover part of the nozzle 212, so that the nozzle 212 is in only partial communication with the nozzle hole 221 to reduce the communication area of the nozzle 212;

the adjusting disk 230 is disposed in the sliding sleeve 220, and a gap 300 is formed between the adjusting disk 230 and the sliding sleeve 220 to facilitate the liquid circulation, the adjusting disk 230 is connected to the sliding sleeve 220 through a connecting member 260, the adjusting disk 230 is disposed along the radial direction of the sliding sleeve 220, that is, the adjusting disk 230 is integrally connected to the sliding sleeve 220 along the radial direction of the sliding sleeve 220, so that the adjusting disk 230 and the sliding sleeve 220 can move synchronously, and further, the adjusting disk 230 is located below the nozzle 221 to reduce the influence of the adjusting disk 230 on the liquid discharge.

As shown in fig. 1, when in use, during pressing, the adjusting disc 230 is subjected to three acting forces, which are respectively the pressure borne by the upper and lower end surfaces of the adjusting disc 230 and the impact force of the pressing liquid, wherein the pressures borne by the upper and lower end surfaces of the adjusting disc 230 are the same and offset with each other, so that the impact force borne by the adjusting disc 230 is only the impact force of the pressing liquid, which is only related to the liquid flow rate, and the larger the liquid flow rate is, the larger the impact force is, the adjusting disc 230 moves toward the plug 240 under the action of the impact force, the movement of the adjusting disc 230 drives the sliding sleeve 220 to move synchronously, the movement of the sliding sleeve 220 not only extrudes the spring 250, so that the spring 250 is compressed to generate an elastic force, but also causes the nozzle 221 and the nozzle 212 to be misaligned, so as to reduce the communication area of the nozzle 221, at this time, the expansion pipe column rapidly starts pressing, the expansion cone 100 starts to work, when the expansion pipe column passes through the reduced diameter position or after the construction is finished, the pump truck stops to suppress, and the flow is 0, and the regulating disc 230 loses the effort that moves towards plug 240 promptly, and sliding sleeve 220 moves towards expand awl 100 under the spring action of spring 250 until reseing, and spout 221 is just right with nozzle 212 setting this moment, and the flow area of nozzle 212 resumes to original size promptly to make the inside and outside liquid of expansion pipe column realize the balance fast, after the inside and outside liquid of expansion pipe column is balanced, the normal size of expansion awl 100 external diameter recovery.

Wherein, because the acting force acting on the adjusting disk 230 is only related to the displacement of the pump truck, but is not related to the pressure difference between the inside and the outside of the pipe column, the initial size of the nozzle 212 of the sliding sleeve 220 can be designed to be larger, thereby conveniently and rapidly realizing the pressure balance.

According to the expansion pipe column, the pressure relief device is arranged, so that the communication area of the nozzle 212 can be automatically adjusted, the expansion pipe column can be quickly pressurized and expanded, and the internal pressure and the external pressure of the expansion pipe column can be quickly balanced.

Further, the upper surface of the plug 240 is provided with a receiving groove 241, the lower end of the spring 250 is connected with the bottom of the receiving groove 241, and the outer diameter of the spring 250 can contact with the inner surface of the receiving groove 241, so that the receiving groove 241 can limit the spring 250, and the spring 250 can be smoothly compressed to generate elastic force.

Further, the gap 300 is greater than or equal to 2mm to ensure that the liquid on the upper and lower sides of the adjusting plate 230 can smoothly flow, so as to ensure that the adjusting plate 230 can smoothly drive the sliding sleeve 220 to move.

Further, as shown in fig. 4, the cross section of the adjusting disc 230 is circular, oval or polygonal, that is, as long as the structure that drives the sliding sleeve 220 to move and extrude the spring 250 under the impact of the fluid can be implemented, the adjusting disc 230 can be used, which is not described herein again, and preferably, the cross section of the adjusting disc 230 is adapted to the cross section of the sliding sleeve 220.

Still further, as shown in fig. 5, the upper surface of the adjusting plate 230 is provided with a pit 232, and the pit 232 is spherical, so that the impact force of the pressurized liquid can better act on the adjusting plate 230, and the adjusting plate 230 can drive the sliding sleeve 220 to move more quickly.

In an embodiment of the present invention, as shown in fig. 2, the connecting member 260 is a connecting rod, a first end of the connecting rod is connected to the sliding sleeve 220, and a second end of the connecting rod is connected to the adjusting plate 230, specifically, the connecting rod is a steel rod, and the steel rod has good strength and can ensure that the adjusting plate 230 is arranged along the radial direction of the sliding sleeve 220.

Further, as shown in fig. 2, a first threaded hole 222 is formed in the side wall of the sliding sleeve 220, a first external thread is formed at the first end of the connecting rod, the connecting rod is connected with the sliding sleeve 220 through the threaded fit of the first external thread and the first threaded hole 222, and the threaded connection mode is simple and convenient, so that the connecting rod and the sliding sleeve 220 can be disassembled and assembled simply and conveniently.

Further, as shown in fig. 2, the bottom surface of the adjusting disk 230 is provided with a second threaded hole 231, the second end of the connecting rod is provided with a convex block 261, the outer peripheral surface of the convex block 261 is provided with a second external thread, the connecting rod is connected with the adjusting disk 230 through the thread fit of the second external thread and the second threaded hole 231, and the mode of the thread connection is simple and convenient, so that the connecting rod and the adjusting disk 230 can be disassembled and assembled simply and conveniently.

Still further, the bump 261 and the connecting rod are of an integrated structure, so that the reliability of connection between the bump 261 and the connecting rod is ensured.

In another embodiment of the present invention, the first end of the connecting rod is welded to the sliding sleeve 220, and the second end of the connecting rod is welded to the adjusting plate 230, and the welding connection is simple and reliable.

In another embodiment of the present invention, the connecting member 260 is a rib connected to the outer circumferential surface of the adjusting disk 230, the inner surface of the sliding sleeve 220 is provided with a slot, and the adjusting disk 230 is connected to the sliding sleeve 220 by the engagement of the rib and the slot, which is simple in engagement and facilitates the detachment of the adjusting disk 230.

Further, the adjusting plate 230 and the rib are of an integrated structure, so as to ensure the reliability of the connection between the adjusting plate 230 and the rib.

The operation of the expansion string of the present invention is described in detail below with reference to the accompanying drawings:

as shown in fig. 1, during pressurization, the larger the liquid flow rate is, the larger the impact force applied to the adjusting disc 230 is, the adjusting disc 230 moves towards the plug 240 under the action of the impact force, the movement of the adjusting disc 230 drives the sliding sleeve 220 to move synchronously, the movement of the sliding sleeve 220 not only extrudes the spring 250 to compress the spring 250 to generate an elastic force, but also causes the nozzle 221 and the nozzle 212 to be dislocated to reduce the communication area of the nozzle 221, at this time, the expansion pipe column rapidly starts to be pressurized, the expansion cone 100 starts to work after undergoing radial expansion, when the expansion pipe column passes through the diameter reduction position or after construction is finished, the pump truck stops pressurization, the flow rate is 0, i.e., the adjusting disc 230 loses the acting force, the sliding sleeve 220 resets under the elastic force of the spring 250, at this time, the nozzle 221 and the nozzle 212 are arranged just opposite to each other, i.e., the flow area of the nozzle 212 returns to the original size, so that the balance of the liquid inside and the liquid outside the expansion pipe column can be rapidly realized, and the liquid inside the expansion pipe column are balanced, the outer diameter of the expansion cone 100 returns to the normal size.

In conclusion, the expansion pipe column provided by the invention can automatically adjust the communication area of the nozzle by arranging the pressure relief device, so that the expansion pipe column can be quickly pressurized and expanded, the internal pressure and the external pressure of the expansion pipe column can be quickly balanced, the return of polluted liquid is less, and the environment is protected.

The above description is only an exemplary embodiment of the present invention, and is not intended to limit the scope of the present invention. Any equivalent changes and modifications that can be made by one skilled in the art without departing from the spirit and principles of the invention should fall within the protection scope of the invention. It should be noted that the components of the present invention are not limited to the above-mentioned whole application, and various technical features described in the present specification can be selected to be used alone or in combination according to actual needs, so that the present invention naturally covers other combinations and specific applications related to the invention.