CN109236229B

CN109236229B - Mixed bridge plug

Info

Publication number: CN109236229B
Application number: CN201811173376.7A
Authority: CN
Inventors: 张伟; 金宁静
Original assignee: Chengdu Vertechs Oil & Gas Technology Co Ltd
Current assignee: Chengdu Vertechs Oil & Gas Technology Co Ltd
Priority date: 2018-10-09
Filing date: 2018-10-09
Publication date: 2019-12-27
Anticipated expiration: 2038-10-09
Also published as: CN109236229A

Abstract

The invention relates to a hybrid bridge plug for temporarily plugging an oil gas shaft, which comprises a mandrel and a rubber cylinder, wherein the rubber cylinder is sleeved on the middle position of the outer surface of the mandrel in a sliding manner, one end of the outer surface of the mandrel, which is positioned on the rubber cylinder, is sequentially sleeved with a first cone sleeve and a first slip seat limiting structure, and one end of the mandrel is provided with a first joint; the outer surface of the mandrel is positioned at the other end of the rubber cylinder and is sequentially sleeved with a second cone sleeve and a push ring, and the other end of the mandrel is provided with a second joint; the mandrel comprises a first mandrel and a second mandrel, the second mandrel is abutted to the first joint, the length of the second mandrel is less than or equal to the setting stroke of the hybrid bridge plug, and the second mandrel and the first joint are made of soluble materials. After all of the bridge plugs in the wellbore have been drilled out prior to production of the oil or gas well, the second mandrel and first sub are dissolved directly with little residue downhole.

Description

Mixed bridge plug

Technical Field

The invention relates to the technical field of downhole tools used for the staged reconstruction of the inner diameter of a temporary plugging casing pipe in oil and gas well fracturing, in particular to a hybrid bridge plug.

Background

In staged fracturing modification operation of oil and gas wells, a composite bridge plug or a cast iron bridge plug is usually used as a staged tool. The two bridge plugs have the advantages that the composite bridge plugs have the characteristic of high drilling and grinding speed, and after the fracturing operation is finished, the composite bridge plugs must be quickly drilled and ground through a coiled tubing to form a full-drift-diameter well hole.

For a traditional bridge plug, a first joint and a second joint are arranged at two ends of the bridge plug, and are provided with mutual meshing structures, so that in drilling and grinding of a plurality of bridge plugs in an oil-gas well, the first joint of the previous bridge plug can fall off to the second joint of the next bridge plug; due to the mutual engagement structure, the first joint of the previous bridge plug is ensured to be completely drilled and ground; but for the last bridge plug in the well the first joint is either dropped directly to the bottom of the well and remains at the bottom.

Meanwhile, after the slips of the bridge plug are drilled and ground, the mandrel of the bridge plug loses the limiting of the slips, and the mandrel at the rear section can fall off to the bottom of the well.

The first joint and the rear section mandrel are left at the bottom of the well, and the production of the oil and gas well is seriously influenced.

Disclosure of Invention

The invention provides a hybrid bridge plug, which aims to solve the technical problem that a large amount of residues exist at the bottom of a well in the process of modifying the conventional bridge plug.

In order to solve the technical problem, the invention provides a hybrid bridge plug which is used for temporarily plugging an oil gas shaft and comprises a hollow mandrel and a rubber cylinder, wherein the rubber cylinder is sleeved on the middle position of the outer surface of the mandrel in a sliding manner, a first cone sleeve and a first slip seat limiting structure are sequentially sleeved on one end, located on the rubber cylinder, of the outer surface of the mandrel, and a first connector is sleeved on one end of the mandrel; a second cone sleeve and a push ring are sequentially sleeved on the outer surface of the mandrel at the other end of the rubber cylinder, and a second joint is sleeved on the other end of the mandrel; the mandrel, the first cone sleeve, the first slip seat limiting structure, the push ring, the second cone sleeve, the first joint and the second joint are all made of composite materials; the core shaft comprises a first core shaft and a second core shaft which are mutually abutted, the second core shaft is abutted with the first joint, when the mixed bridge plug is completely set, the second core shaft is positioned on the outer side of the slip, the length of the second core shaft is smaller than or equal to the set stroke of the mixed bridge plug, and the second core shaft and the first joint are made of soluble materials.

The invention has the beneficial effects that: setting the bridge plug into a two-section structure, wherein the length of the second mandrel is less than or equal to the setting stroke of the mixed bridge plug; that is, when setting is complete, the second mandrel is out of the slip path, i.e., the second mandrel is exposed out of the slips. Meanwhile, the second mandrel and the first joint are made of soluble materials, so that all bridge plugs in a shaft are drilled and ground before the oil and gas well needs to be produced, the second mandrel and the first joint can be directly dissolved, and almost no residue exists at the bottom of the well. Furthermore, the bridge plug is arranged into a two-section structure, and the length of the second mandrel is less than or equal to the setting stroke of the hybrid bridge plug; when the bridge plug setting is completed, the clamping force of the slips acts on the first mandrel, and the reliability of the bridge plug is ensured because the first mandrel is made of insoluble materials.

Further, the length of the first joint is between 1/5 and 1/6 of the mandrel length.

The beneficial effect of adopting the further scheme is that: conventional bridge plugs are relatively heavy because the entire first connector length can reach 1/4 to 1/5 of the mandrel length due to the provision of the engagement structure to match the engagement between the two connectors. The first joint made of the soluble material is high in hardness, the strength requirement of the bridge plug can be met without setting the first joint for a long time, the weight and the length of the bridge plug are reduced, and the convenience of the bridge plug is improved.

Further, a second slip seat limiting structure is sleeved on the mandrel and located between the second cone sleeve and the push ring; and the second slip seat limiting structure and the first slip seat limiting structure are provided with limiting slips.

The beneficial effect of adopting the further scheme is that: the double-limiting slip is simple in structure, and reliable and stable in limiting.

Further, be provided with in the first joint and lose the bracelet, lose the bracelet with first joint threaded connection.

The beneficial effect of adopting the further scheme is that: through setting up alone and losing the bracelet, the operation of the bridge plug setting of being convenient for improves the reliability of setting.

Advance one, the hand ring of losing is soluble material preparation and forms.

The beneficial effect of adopting the further scheme is that: the throwing ring is also a soluble material, so that the bridge plug component is further ensured not to be remained in the well bottom.

Further, a through hole is formed in the second mandrel in the radial direction.

The beneficial effect of adopting the further scheme is that: in the product in-service use process, have a plurality of bridging plugs and use together, in the fracturing work progress, the one end of the dabber in the bridging plug can seal the dabber internal diameter through the ball sealer, when the ball sealer of lower bridging plug returns to arrange this bridging plug and set up the position when returning to arrange, the ball sealer can contact bottom the nipple joint with the lower clutch, nevertheless can not block up the through-hole, well fluid still has flow channel when returning to arrange.

Further, the bypass hole is a plurality of.

The beneficial effect of adopting the further scheme is that: the plurality of through holes prevent one of the holes from being blocked to influence the well fluid flow-back.

Furthermore, a plurality of through holes are uniformly distributed on the circumference of the second mandrel.

The beneficial effect of adopting the further scheme is that: the even distribution of through-hole sets up the smoothness nature of guaranteeing the liquid flow around the bridging plug.

Further, the end of the first joint is of a plane structure.

The beneficial effect of adopting the further scheme is that: conventional bridge plugs are provided with engagement structures for mating engagement between two connectors. The first joint made of soluble materials does not need to be provided with an engaging structure, so that the weight and the length of the bridge plug are reduced, and the convenience of the bridge plug is improved.

Further, the outer surface roughness Ra of the first mandrel is less than 6.3.

The beneficial effect of adopting the further scheme is that: the first connector made of soluble materials has high surface smoothness, small friction coefficient and convenient setting process.

Further, the other end of the second joint is provided with an interlocking structure.

The beneficial effect of adopting the further scheme is that: the other end that the second connects is provided with interlocking structure, is convenient for match with conventional bridge plug, realizes with the whole adaptation of conventional bridge plug and use, has improved the application range and the commonality of product.

Drawings

FIG. 1 is a schematic cross-sectional view of an embodiment of the present invention,

figure 2 is a schematic cross-sectional view of a seated configuration in accordance with an embodiment of the present invention,

in the drawings, the components represented by the respective reference numerals are listed below:

1. a second joint, 2, a mandrel, 21, a first mandrel, 22, a second mandrel, 3, a push ring, 4, a second slip seat limiting structure, 5, a limiting slip, 6, a second cone sleeve, 7, a rubber cylinder, 8, a first cone sleeve, 9, a first slip seat limiting structure, 10, a first joint, 11, a releasing ring, 12, an interlocking structure, 13, an oil and gas well bore, 14, a fracturing ball

Detailed Description

The present invention will be further described with reference to the accompanying drawings and embodiments.

Referring to fig. 1, a schematic cross-sectional view of a hybrid bridge plug according to an embodiment of the invention is used for temporarily plugging an oil and gas wellbore, and includes a hollow mandrel 2 and a rubber cylinder 7, wherein the rubber cylinder 7 is slidably sleeved on the middle position of the outer surface of the mandrel 2, a first cone sleeve 8 and a first slip seat limiting structure 9 are sequentially sleeved on one end of the outer surface of the mandrel 2, which is located at the rubber cylinder 7, and a first joint 10 is sleeved on one end of the mandrel 2; the outer surface of the mandrel 2 is positioned at the other end of the rubber cylinder 7 and is sequentially sleeved with a second cone sleeve 6 and a push ring 3, and the other end of the mandrel 2 is sleeved with a second joint 1; the mandrel 2, the first cone sleeve 8, the first slip seat limiting structure 9, the push ring 3, the second cone sleeve 6, the first joint 10 and the second joint 1 are all made of composite materials; the mandrel 2 comprises a first mandrel 21 and a second mandrel 22 which are mutually abutted, the second mandrel 22 is abutted with the first connector 10, the length of the second mandrel 22 is less than or equal to the setting stroke of the hybrid bridge plug, and when the hybrid bridge plug is completely set, the second mandrel 22 is positioned on the outer side of the slips 9. The second mandrel 22 and the first joint 10 are made of a soluble material. A second slip seat limiting structure 4 is sleeved on the mandrel 2, and the second slip seat limiting structure 4 is positioned between the second cone sleeve 6 and the push ring 3; and the second slip seat limiting structure 4 and the first slip seat limiting structure 9 are provided with limiting slips 5.

The composite material in this embodiment means: fiber composites, sandwich composites, particulate composites, hybrid composites, and the like, which are commonly used in the art.

Soluble materials in this embodiment refer to: soluble magnesium aluminum alloy, polyglycolic acid (PGA), and the like, which are commonly used in the art.

The working principle of the bridge plug is as follows: the mixed bridge plug is matched with the setting adapter and then is connected with a setting tool together and then enters a well, namely the setting adapter is in adaptive connection with the releasing ring, after the designed setting depth is reached, the setting tool is triggered to generate certain thrust to push the push ring 3 to move downwards, and the rubber cylinder 7 is extruded and generates elastic deformation and contacts with the inner wall of the casing pipe to form initial sealing; when the thrust is larger than the breaking force of the first slip seat limiting structure 4 and the second slip seat limiting structure 4, the slip seat limiting structures will break and move along the conical surfaces of the first cone sleeve 6 and the second cone sleeve 6 until the limiting slips 5 are tightly anchored with the inner wall of the oil-gas well bore; when the thrust that the setting instrument provided continues to increase, after the shearing pin shearing force that is greater than the setting adapter, set, lose the bracelet and fall with the setting adapter, the bridge plug is stayed at the design setting degree of depth, then accomplishes perforation operation and retrieves the setting instrument, drops into the soluble fracturing ball of corresponding size at the well head. The soluble fracturing ball can fall on the ball seat at the top of the mandrel 2 of the hybrid bridge plug under the action of gravity in the vertical well section, and can be pushed to fall on the ball seat at the top of the mandrel 2 of the hybrid bridge plug by injecting liquid in the horizontal well section. After the fracturing ball falls on the ball seat, fracturing liquid is continuously pumped by a fracturing pump truck to apply pressure to the ball, so that the sealing between the ball and the ball seat can be realized, the fracturing liquid can enter the stratum through perforation holes in the casing pipe to start fracturing the stratum, when the total amount of the designed propping agent is completely pumped into the stratum, the fracturing construction is completed, and the steps are repeated until all layers are transformed.

In the field of bridge plug technology, the setting stroke is the distance that the slips move relative to the mandrel, that is, the length of the mandrel exposed out of the slips after the slips move.

The hybrid bridge plug in this embodiment is set at the last position in the entire downhole, and after setting is completed, the second mandrel is out of the slip stroke, as shown in fig. 2; the bridge plug is left in the oil gas shaft 13 to design the setting depth, then perforation operation is completed, the setting tool is recovered, soluble fracturing balls 14 with corresponding sizes are thrown into a wellhead, and then the mandrel is pushed to move, so that the second mandrel 22 is completely positioned outside the first slip seat limiting structure 9. Meanwhile, as the second mandrel 22 and the first connector 10 are made of soluble materials, when the oil and gas well needs to be reformed for the second time, the second mandrel 22 and the first connector can be directly dissolved, and almost no residue exists at the bottom of the well. Furthermore, the bridge plug is provided with a two-section structure, and the length of the second mandrel 22 is less than or equal to the setting stroke of the hybrid bridge plug; when the bridge plug setting is completed, the clamping force of the slips acts on the first mandrel, and the reliability of the bridge plug is ensured because the first mandrel is made of insoluble materials.

In this embodiment, the length of the first joint 10 is 1/5 the length of the mandrel 2.

Conventional bridge plugs are relatively heavy because the entire first connector length can reach 1/4 to 1/5 of the mandrel length due to the provision of the engagement structure to match the engagement between the two connectors. The first joint made of the soluble material is high in hardness, the strength requirement of the bridge plug can be met without setting the first joint for a long time, the weight and the length of the bridge plug are reduced, and the convenience of the bridge plug is improved.

In the present embodiment, the release ring 11 is made of soluble material; the lost ring can be dissolved away, and the bridge plug component can not remain in the well bottom.

In the present embodiment, a plurality of through holes are provided in the radial direction of the second mandrel 22, and the plurality of through holes are uniformly distributed in the circumferential direction of the second mandrel 22.

In the actual use process of a product, a plurality of bridge plugs are used together, in the fracturing construction process, one end of a mandrel in each bridge plug can seal the inner diameter of the mandrel through a sealing ball, when the sealing ball of a lower bridge plug is discharged back to the bridge plug setting position in the back discharge process, the sealing ball can be in contact with the bottom of a lower connector short section, but cannot block a through hole, and well fluid still has a flow channel in the back discharge process; the even distribution of through-hole sets up the smoothness nature of guaranteeing the liquid flow around the bridging plug. Meanwhile, the second mandrel is made of a soluble material and is provided with a plurality of through holes, so that the contact area of the underground slurry and the second mandrel is increased, and the dissolving speed of the second mandrel is increased.

In this embodiment, the end of the first connector 10 is a planar structure.

Conventional bridge plugs are provided with engagement structures for mating engagement between two connectors. The first joint made of soluble materials does not need to be provided with an engaging structure, so that the weight and the length of the bridge plug are reduced, and the convenience of the bridge plug is improved.

The outer surface roughness Ra of the first mandrel 21 was 3.2.

The first connector made of soluble materials has high surface smoothness, small friction coefficient and convenient setting process.

In this embodiment, the other end of the second joint 1 is provided with an interlocking structure 12.

The other end of the second joint 1 is provided with an interlocking structure, so that the second joint can be conveniently matched with a conventional bridge plug, the integral adaptation and use of the conventional bridge plug are realized, and the application range and the universality of a product are improved.

In the description of the present invention, it is to be understood that the terms "center", "length", "width", "up", "down", "vertical", "horizontal", "top", "bottom", "inner", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

The hybrid bridge plug of the present invention is described in detail above, and the principles and embodiments of the present invention are described herein using specific examples. The above description of the embodiments is only intended to facilitate the understanding of the core ideas of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims

1. A hybrid bridge plug is used for temporarily plugging an oil gas shaft and is characterized by comprising a hollow mandrel (2) and a rubber cylinder (7), wherein the rubber cylinder (7) is sleeved on the middle position of the outer surface of the mandrel (2) in a sliding manner, one end, located on the rubber cylinder (7), of the outer surface of the mandrel (2) is sequentially sleeved with a first cone sleeve (8) and a first slip seat limiting structure (9), and one end of the mandrel (2) is sleeved with a first connector (10); the outer surface of the mandrel (2) is positioned at the other end of the rubber cylinder (7) and is sequentially sleeved with a second cone sleeve (6) and a push ring (3), and the other end of the mandrel (2) is sleeved with a second joint (1); the mandrel (2), the first cone sleeve (8), the first slip seat limiting structure (9), the push ring (3), the second cone sleeve (6), the first joint (10) and the second joint (1) are all made of composite materials; the mandrel (2) comprises a first mandrel (21) and a second mandrel (22) which are mutually abutted, the second mandrel (22) is abutted to the first joint (10), the length of the second mandrel (22) is smaller than or equal to the setting stroke of the hybrid bridge plug, when the hybrid bridge plug completes setting, the second mandrel (22) is located on the outer side of the slip (9), and the second mandrel (22) and the first joint (10) are made of soluble materials.

2. The hybrid bridge plug of claim 1, wherein the length of the first joint (10) is between 1/5 and 1/6 of the length of the mandrel (2).

3. The hybrid bridge plug according to claim 1 or 2, wherein a second slip seat limiting structure (4) is sleeved on the mandrel (2), and the second slip seat limiting structure (4) is located between the second cone sleeve (6) and the push ring (3); and the second slip seat limiting structure (4) and the first slip seat limiting structure (9) are provided with limiting slips (5).

4. The hybrid bridge plug according to claim 3, characterized in that a throwaway ring (11) is provided in the first joint (10), the throwaway ring (11) being in threaded connection with the first joint (10).

5. Hybrid bridge plug according to claim 4, characterised in that the throwaway ring (11) is made of soluble material.

6. A hybrid bridge plug according to claim 1 or 2, characterized in that the second mandrel (22) is provided with a through hole in the radial direction.

7. The hybrid bridge plug of claim 6, wherein the through-hole is plural.

8. The hybrid bridge plug of claim 7, wherein a plurality of the through-holes are evenly distributed in the circumferential direction of the second mandrel (22).

9. The hybrid bridge plug according to claim 1 or 2, wherein the end of the first joint (10) is of planar configuration.

10. The hybrid bridge plug of claim 1 or 2, wherein the first mandrel (21) has an outer surface roughness Ra of less than 6.3.