CN108571299B

CN108571299B - Bridge plug

Info

Publication number: CN108571299B
Application number: CN201710148074.3A
Authority: CN
Inventors: 薛占峰; 吴晋霞; 魏辽; 崔晓杰; 袁大勇; 马善坤
Original assignee: China Petroleum and Chemical Corp; Sinopec Research Institute of Petroleum Engineering
Current assignee: China Petroleum and Chemical Corp; Sinopec Research Institute of Petroleum Engineering
Priority date: 2017-03-13
Filing date: 2017-03-13
Publication date: 2020-07-31
Anticipated expiration: 2037-03-13
Also published as: CN108571299A

Abstract

The invention relates to a bridge plug. This bridging plug includes the bridging plug body, and the cover is equipped with the slips and is in the slips driving piece on slips upper reaches on the bridging plug body, and the slips driving piece links to each other through elastic anti-moving back mechanism with the bridging plug body. The bridge plug body is also sleeved with an elastic body, and the elastic body is positioned at the downstream of the slips and is abutted against the slips. When the bridge plug is used, after the slips are hung and the slip driving piece is unloaded, the elastic rubber barrel can extrude the slips, so that the slips are prevented from returning or even being hung.

Description

Bridge plug

Technical Field

The invention relates to an oil field development tool, in particular to a bridge plug.

Background

In the process of oil field development, the bridge plug staged fracturing method is more and more widely applied. In the method, a cable or a coiled tubing is adopted to lower the bridge plug step by step, and the fracturing construction is carried out after the bridge plug is set, seated and hung.

In order to ensure that the bridge plug can be drilled out so as to further reform the reservoir in the later stage, the commonly used bridge plug adopts the whole slip made of cast iron as a suspension device, and an anti-backing mechanism is used for preventing backing. However, after the whole slip is hung in a sitting mode, due to the structural limitation of the anti-back mechanism, a small amount of back-off phenomenon usually occurs, so that the slip is hung in a sitting mode or is hung in an unhooking mode, and then the bridge plug is layered and loses efficacy.

Disclosure of Invention

In order to solve the problems, the invention provides a bridge plug. When the bridge plug is used, after the slips are hung and the slip driving piece is unloaded, the elastic rubber barrel can extrude the slips, so that the slips are prevented from returning or even being hung.

The bridge plug comprises a bridge plug body, wherein a slip and a slip driving piece positioned at the upstream of the slip are sleeved on the bridge plug body, and the slip driving piece is connected with the bridge plug body through an elastic anti-back mechanism. The bridge plug body is also sleeved with an elastic body, and the elastic body is positioned at the downstream of the slips and is abutted against the slips.

In construction using the bridge plug of the present invention, a downstream-facing force is first applied to the slip drivers to move the slip drivers downstream to move the slips downstream and expand outward to complete the setting. The slips moving downstream may cause a squeeze on the elastomer. After the setting is completed, and after the slip driver is unloaded (i.e., the force is removed), the squeezed elastomer will expand and push the slips upstream until the slips and slip driver are tightly abutted together. Therefore, under the clamping of the elastic body and the slip driving piece, the slip cannot retreat, and further cannot be hung.

In one embodiment, the end edge of the elastomer is fitted with an anti-extrusion ring. In a preferred embodiment, the elastomer is a glue barrel. The hardness of the anti-extrusion ring is greater than that of an elastomer, such as a metal annulus. Therefore, the extrusion force of the slips to the rubber barrel is borne by the anti-protruding ring, so that the slips are prevented from damaging the rubber barrel.

In one embodiment, the anti-rotation device further comprises an anti-rotation pin arranged on the bridge plug body, the anti-rotation pin is clamped with the gap of the slip, and the elastic body presses the anti-rotation pin on the bridge plug body. According to the structure, the anti-rotation pin cannot move relative to the bridge plug body under the action of the elastic body, so that the slip clamped with the elastic body cannot move relative to the bridge plug body. Thus, when the bridge plug is drilled out later, the slips can be kept suspended instead of rotating along with the drill bit, so that the bridge plug can be conveniently drilled out.

In one embodiment, the number of anti-rotation pins matches the number of slip slots.

In a preferred embodiment, recesses are formed in the elastomer body, which recesses hold the rotation-blocking pins. Thus, the elastic body can hold the rotation preventing pin more stably.

In one embodiment, the bridge plug body includes a base and a socket disposed on the base, the socket extending from a downstream end of the base to the anti-backup mechanism, and the anti-backup pin being mounted on the socket.

In one embodiment, the downstream end of the cartridge has a radially outward projection on which a receiving groove is formed for receiving an anti-rotation pin. The receiving slots make the anti-rotation pins more stable (i.e., do not move relative to the bridge plug body). In addition, by providing the receiving groove, it is also made easier to mount the rotation preventing pin at an accurate position.

In one embodiment, the anti-retreat mechanism is a clamp spring, the upstream surface of the clamp spring is an inclined surface, and the downstream surface of the clamp spring is a vertical surface.

In one embodiment, the slip driver is a cone sleeve that is axially movable.

Compared with the prior art, the invention has the advantages that: (1) after the slips are completely hung, after the slip driving piece is unloaded, the extruded elastic body can be expanded to push the slips upstream until the slips and the slip driving piece are tightly abutted together. Therefore, under the clamping of the elastic body and the slip driving piece, the slip cannot retreat, and further cannot be hung. (2) Through installing the anti-rotating pin on the bridge plug, can also conveniently bore the bridge plug in the later stage and remove.

Drawings

The invention will be described in more detail hereinafter on the basis of embodiments and with reference to the accompanying drawings. Wherein:

FIG. 1 schematically illustrates the structure of a bridge plug according to the present invention;

FIG. 2 is an enlarged view of portion A of FIG. 1;

fig. 3 schematically shows the structure of an elastic body according to the present invention.

In the drawings, like parts are provided with like reference numerals. The drawings are not to scale.

Detailed Description

The invention will be further explained with reference to the drawings.

FIG. 1 schematically shows a bridge plug 100 according to the present invention. As shown in fig. 1, the bridge plug 100 includes at least a plug body 2, slips 3 fitted over the plug body 2, a slip driver 1 upstream of the slips 3, and an elastomer 4 downstream of the slips 3. The slip driver 1 and the resilient member 4 each contact a respective end of the slips 3. The slip driving piece 1 is also connected with the bridge plug body 2 through an elastic anti-back mechanism 8. In the event of a downstream-directed force, the slip driver 1 can move downstream along the plug body 2 beyond the anti-roll back mechanism 8 and push the slips 3 radially outward and downstream, causing the slips 3 to radially expand (thereby effecting a ride) and push the elastomer 4. After the force on the slip driver 1 is removed, the elastomer 4 may push the slips 3 slightly upstream so that the slips 3 are in intimate contact with both the slip driver 1 and the elastomer 4, thereby preventing the slips 3 from backing off and, thus, preventing the slips 3 from becoming unsettled. Note that in the present application, "upstream" refers to the direction of the arrow 10 in fig. 2, and "downstream" is the opposite direction to "upstream".

Preferably, the slip driver 1 is configured as a drogue. The inner surface of the upstream portion of the slips 3 is configured to conform to the taper of the taper sleeve. In this way the slip driver 1 can be moved very easily under force between the slips 3 and the plug body 2, thereby flaring the slips 3 radially outwardly and moving downstream. In another preferred embodiment, the anti-back mechanism 8 is a clamp spring, the upstream surface of the clamp spring 8 is an inclined surface, and the downstream surface is a vertical surface. This allows the slip driver 1 to move easily downstream but not upstream (due to the blocking action of the vertical surfaces of the circlips), thus ensuring that the slip driver 1 and the elastomer 4 tightly grip the slips 3 and preventing the slips 3 from backing out or even hanging apart.

As shown in fig. 1 or 2, the bridge plug 100 further includes an anti-rotation pin 6. The anti-rotation pins 6 are pressed against the bridge plug body 2 by the elastic body 4 and snap into the slots of the slips 3 (the structure of the slips 3 is well known to those skilled in the art and will not be described here), even after the slips 3 are opened. The number of anti-rotation pins 6 matches the number of slots of the slips 3. It should be noted that the anti-rotation pins 6 are downstream of and spaced from the slip driver 1 so that there is sufficient space for the slip driver 1 to move downstream. The anti-rotation pin 6 is arranged for the purpose of: the anti-rotation pins 6 are fixed relative to the plug body 2 due to the captive action of the elastomer 4 and therefore the slips 3 are also fixed relative to the plug body 2. Thus, the bridge plug body 2, the taper sleeve 1, the slips 3, the anti-rotation pin 6 and the elastic body 4 form a whole fixed in the sleeve. When the bridge plug 100 is drilled out, the slips 3 still have the hanging capability even when the slips 3 are drilled and milled, but the slips 3 are rotated together with the drill bit, so that the whole bridge plug 100 can be conveniently drilled out.

The elastomer 4 is preferably configured as a glue bucket. Fig. 3 schematically shows the structure of the glue barrel 4 (or elastomer). As shown in fig. 3, a recess 41 for holding the rotation prevention pin 6 is provided on the inner wall of the glue barrel 4. In this way, the anti-rotation pins 6 can be positioned easily, simplifying the assembling work of the bridge plug 100.

As also shown in fig. 2 and 3, a hard anti-protrusion ring 5 is mounted on the upstream end edge of the glue barrel 4. In one embodiment, the anti-extrusion ring 5 is a metal annulus. In the assembled state, the downstream ends of the slips 3 would press against the anti-extrusion ring 5, rather than directly against the glue barrel 4. Thus, the anti-protruding ring 5 can directly bear the extrusion force of the slips 3 on the rubber barrel 4, and the strength of the anti-protruding ring 5 is greater than that of the rubber barrel 4, so that the rubber barrel 4 is prevented from being damaged by the slips 3.

As shown in fig. 2 again, the bridge plug body 2 includes a base 21 and a clamping seat 7 sleeved on the base 21. The clamping seat 7 is fixedly connected to the base body 21 by means of a bolt 73 at its downstream end and extends upstream to the anti-backup mechanism 8. Thus, the slip driver 1 will move downstream along the cartridge 7 after passing over the anti-back mechanism 8.

The anti-rotation pin 6 is mounted on the card holder 7. Specifically, a radially outward projection 71 is provided at the downstream end portion of the holder 7, and a receiving groove 72 for receiving the rotation preventing pin 6 is formed on the projection 71. Thus, the anti-rotation pin 6 is more stable under the combined action of the bearing groove 72 and the glue barrel 4, so that the slip 3 can be more stably fixed. It should be noted that the downstream end edge of the glue barrel 4 is also fitted with a hard anti-extrusion ring 5. Thus, when the glue barrel 4 is pressed, the downstream end portion thereof is not damaged by the projection 71 of the cartridge 7.

In general, the bridge plug 100 of the present invention does not get unhooked due to slip retraction, and can be conveniently and quickly drilled out at a later stage.

While the invention has been described with reference to a preferred embodiment, various modifications may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In particular, the technical features mentioned in the embodiments can be combined in any way as long as there is no structural conflict. It is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. A bridge plug, comprising:

the bridge plug comprises a bridge plug body, wherein a slip and a slip driving piece positioned at the upstream of the slip are sleeved on the bridge plug body, the slip driving piece is connected with the bridge plug body through an elastic anti-return mechanism,

an elastomer is further sleeved on the bridge plug body, the elastomer is located at the downstream of the slips and is abutted with the slips,

the anti-rotation pin is arranged on the bridge plug body and is clamped with the gap of the slip, the elastomer compresses the anti-rotation pin on the bridge plug body,

the bridge plug body comprises a base body and a clamping seat sleeved on the base body, the clamping seat extends to the anti-backing mechanism from the downstream end of the base body, the anti-rotating pin is installed on the clamping seat, the downstream end of the clamping seat is provided with a radial outward bulge, and a bearing groove for bearing the anti-rotating pin is formed in the bulge.

2. The bridge plug of claim 1, wherein an end edge of the elastomer body is fitted with an anti-extrusion ring.

3. The bridge plug of claim 2, wherein the elastomer is a rubber barrel and the anti-extrusion ring is a metal annulus.

4. The bridge plug of claim 1, wherein the number of anti-rotation pins matches the number of slips' slots.

5. The bridge plug according to claim 4, wherein a recess is configured on the elastomer to clamp the anti-rotation pin.

6. The bridge plug of claim 1, wherein the anti-back-off mechanism is a circlip, an upstream face of the circlip being a sloped face and a downstream face being a vertical face.

7. A bridge plug as claimed in any of claims 1 to 6, wherein the slip drive is an axially movable taper sleeve.