WO2020073349A1

WO2020073349A1 - Mixture bridge plug

Info

Publication number: WO2020073349A1
Application number: PCT/CN2018/110680
Authority: WO
Inventors: 张伟; 金宁静
Original assignee: 成都维泰油气能源技术有限公司
Priority date: 2018-10-09
Filing date: 2018-10-17
Publication date: 2020-04-16

Abstract

Disclosed is a mixture bridge plug for temporarily plugging an oil and gas wellbore. The bridge plug comprises a core shaft (2) and a rubber cylinder (7), wherein the rubber cylinder (7) is slidably sheathed onto the middle of an outer surface of the core shaft (2); a first conical sleeve (8) and a first clamp seat limiting structure (9) are successively sheathed onto one end, at the rubber cylinder (7), of the outer surface of the core shaft (2), and a first connector (10) is provided at one end of the core shaft (2); a second conical sleeve (6) and a push ring (3) are successively sheathed onto the other end, at the rubber cylinder (7), of the outer surface of the core shaft (2), and a second connector (1) is provided at the other end of the core shaft (2); and the core shaft (2) comprises a first core shaft (21) and a second core shaft (22), wherein the second core shaft (22) abuts against the first connector (10); the length of the second core shaft (22) is smaller than or equal to a travel distance of a packer of the mixture bridge plug; and the second core shaft (22) and the first connector (10) are made of soluble materials. Before oil-gas well production, after all the bridge plugs in the wellbore are drilled off, the second core shaft (22) and the first connector (10) can be directly dissolved, and little residue is left at the bottom of a well.

Description

Hybrid bridge plug

Technical field

The invention relates to the technical field of a downhole tool used for temporarily blocking the inner diameter of a casing in fracturing and staged reconstruction of oil and gas wells, in particular to a hybrid bridge plug.

Background technique

In the staged fracturing and reforming operations of oil and gas wells, composite bridge plugs or cast iron bridge plugs are usually used as tools for segmentation. These two kinds of bridge plugs have their own advantages. For example, composite bridge plugs have the characteristics of fast drilling and grinding speed. After the fracturing operation, these composite bridge plugs must be quickly drilled and milled through coiled tubing to form a full-bore wellbore. .

For a traditional bridge plug, a first joint and a second joint are provided at both ends of the bridge plug. The first joint and the second joint are provided with an intermeshing structure. In the drilling and grinding of multiple bridge plugs in oil and gas wells, the previous one The first joint of the bridge plug will fall off to the second joint of the next bridge plug; due to the inter-engagement structure, it is ensured that the first joint of the previous bridge plug is completely drilled out; but for the last bridge plug in the oil and gas well, the first The joint may fall off directly to the bottom of the oil and gas well and remain at the bottom of the well.

At the same time, after the slip of the bridge plug is drilled and polished, the mandrel of the bridge plug loses the limit of the slip, and the mandrel in the rear section will also fall off to the bottom of the well.

The above-mentioned first joint and the rear mandrel remain at the bottom of the well, which seriously affects the production of oil and gas wells.

Summary of the invention

The invention provides a hybrid bridge plug to solve the technical problem that the existing bridge plug has a large amount of residues at the bottom of the well during the transformation process.

In order to solve the above technical problems, the present invention provides a hybrid bridge plug for temporarily plugging an oil and gas wellbore, which includes a hollow mandrel and a rubber cylinder, and the rubber cylinder is slidably sleeved on the middle of the outer surface of the mandrel , The outer surface of the mandrel is located at one end of the rubber sleeve, and a first cone sleeve and a first slip seat limiting structure are sequentially sleeved, and one end of the mandrel is sleeved with a first joint; The outer surface of the mandrel is located at the other end of the rubber sleeve, and a second cone sleeve and a push ring are sequentially sleeved, and the other end of the mandrel is sleeved with a second joint; the mandrel, the first The cone sleeve, the first slip position limiting structure, the push ring, the second cone sleeve, the first joint and the second joint are all made of composite materials; The mandrel includes a first mandrel and a second mandrel that are in contact with each other, the second mandrel is in contact with the first joint, and when the hybrid bridge plug is seated, the second mandrel The length of the second mandrel located on the outside of the slip is less than or equal to the seating stroke of the hybrid bridge plug, the second mandrel and The first joint is made of soluble material.

The beneficial effect of the present invention is that: the bridge plug is arranged in a two-stage structure, and the length of the second core shaft is less than or equal to the sealing stroke of the hybrid bridge plug; that is, when the sealing is completed, the second core The shaft is located outside of the slip, that is, the second mandrel is exposed outside the slip. At the same time, since the second mandrel and the first joint are made of soluble materials, before the oil and gas well needs production, all bridge plugs in the wellbore, the second mandrel and the first joint are drilled and ground It will dissolve directly, with almost no residue at the bottom of the well. Furthermore, the bridge plug is arranged in a two-stage structure, and the length of the second mandrel is less than or equal to the seating stroke of the hybrid bridge plug; when the sealing of the bridge plug is completed, the clamping force of the slips acts on On the first mandrel, since the first mandrel is an insoluble material, the reliability of the bridge plug is ensured.

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

The beneficial effect of using the above further scheme is that the conventional bridge plug is provided with an engagement structure in order to match the engagement between the two joints, the length of the entire first joint will reach 1/4 to 1/5 of the length of the mandrel, and the bridge plug is bulky . The first joint adopting the soluble material has high hardness, and the strength requirement of the bridge plug can be achieved without setting a long length, which reduces the weight and length of the bridge plug and improves the convenience of the bridge plug.

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

The beneficial effect of adopting the above further scheme is that the structure of the double limit slip is simple, and the limit is reliable and stable.

Further, the first joint is provided with a wristband, and the wristband is screw-connected with the first joint.

The beneficial effect of adopting the above-mentioned further scheme is that, by separately setting the lost bracelet, the operation of the bridge plug seat seal is facilitated, and the reliability of the seat seal is improved.

Further, the lost bracelet is made of soluble materials.

The beneficial effect of adopting the above-mentioned further scheme is that the lost bracelet is also a soluble material, which further ensures that the bridge plug components will not remain in the bottom of the well.

Further, the second core shaft is provided with a through hole in the radial direction.

The beneficial effect of using the above further scheme is that during the actual use of the product, multiple bridge plugs will be used together. During the fracturing process, one end of the mandrel in the bridge plug will seal the inner diameter of the mandrel through the sealing ball to return When the sealing ball of the lower bridge plug is returned to the seated position of the bridge plug during discharging, the sealing ball will contact the bottom of the lower joint stub, but it will not block the through hole, and the well fluid will still have a flow channel when returning.

Further, there are multiple bypass holes.

The beneficial effect of adopting the above-mentioned further scheme is that multiple through holes prevent one of the holes from clogging and affecting well fluid backflow.

Further, a plurality of the through holes are evenly distributed in the circumferential direction of the second mandrel.

The beneficial effect of adopting the above further scheme is that the uniform distribution of the through holes ensures smooth flow of liquid around the bridge plug.

Further, the end of the first joint has a planar structure.

The beneficial effect of adopting the above further solution is that the conventional bridge plug is provided with an engagement structure in order to match the engagement between the two joints. The first joint adopting the soluble material does not need to be provided with an engagement structure, which reduces the weight and length of the bridge plug and improves the convenience of the bridge plug.

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

The beneficial effect of adopting the above further scheme is that the surface smoothness of the first joint adopting the soluble material is high, the friction coefficient is small, and the sealing process is more convenient.

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

The beneficial effect of adopting the above further scheme is that the other end of the second joint is provided with an interlocking structure, which is convenient for matching with the conventional bridge plug, realizes the overall adaptation and use of the conventional bridge plug, and improves the range and versatility of the product.

BRIEF DESCRIPTION

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

2 is a schematic diagram of a cross-sectional structure after sealing according to an embodiment of the present invention,

In the drawings, the list of parts represented by each reference number is as follows:

1. The second joint, 2. The mandrel, 21, the first mandrel, 22, the second mandrel, 3. The push ring, 4. The limit structure of the second slip holder, 5. The limit slip, 6. The second cone sleeve, 7, rubber cartridge, 8, the first cone sleeve, 9, the first slip holder limit structure, 10, the first joint, 11, the lost bracelet, 12, the interlocking structure , 13, oil and gas wellbore, 14, fracturing ball

detailed description

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

A schematic cross-sectional view of a hybrid bridge plug according to an embodiment of the present invention is shown in FIG. 1, and is used to temporarily block an oil and gas wellbore, including a hollow mandrel 2 and a rubber cylinder 7. In terms of position, the outer surface of the mandrel 2 is located at one end of the rubber cylinder 7 in turn with a first cone sleeve 8 and a first slip holder limiting structure 9, and one end of the mandrel 2 is sleeved with a first joint 10; The outer surface of the mandrel 2 is located at the other end of the rubber cylinder 7 and the second cone sleeve 6 and the push ring 3 are sleeved in sequence. The other end of the mandrel 2 is sleeved with a second joint 1; the mandrel 2 and the first cone The body sleeve 8, the first slip holder 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 includes Connected to the first mandrel 21 and the second mandrel 22, the second mandrel 22 is in contact with the first joint 10, the length of the second mandrel 22 is less than or equal to the sealing stroke of the hybrid bridge plug, when the hybrid bridge plug is completed When the seat is sealed, the second mandrel 22 is located outside the slip 9. The second mandrel 22 and the first joint 10 are made of soluble materials. The mandrel 2 is sleeved with a second slip holder limit structure 4, the second slip holder limit structure 4 is located between the second cone sleeve 6 and the push ring 3; the second slip holder limit structure 4 A limited-position slip 5 is set on the limiting structure 9 of the first slip.

In this embodiment, the composite material refers to: fiber composite material, sandwich composite material, fine particle composite material, hybrid composite material and other materials commonly used in the technical field.

In this embodiment, the soluble material refers to: soluble magnesium aluminum alloy, polyglycolic acid (PGA) and other materials commonly used in the technical field.

The working principle of the bridge plug is: the hybrid bridge plug is connected with the setting adapter together with the setting tool and then enters the well, that is, the setting adapter is connected to the lost bracelet, and after reaching the design setting depth, by triggering the setting tool It generates a certain thrust, pushes the push ring 3 downward, and the rubber cylinder 7 will be squeezed and elastically deformed and contact the inner wall of the sleeve to form an initial seal; when the thrust is greater than the first and second slip seat limit structures After the rupture force of 4, the limit structure of the slip holder will rupture and move along the conical surface of the first and second cone sleeves 6 until the limit slip 5 is tightly anchored with the inner wall of the oil and gas wellbore; The thrust provided by the sealing tool continues to increase until it is greater than the shearing force of the shear pin of the setting adapter, the setting seal, the bracelet and the setting adapter fall off, the bridge plug remains at the design setting depth, and then the perforating operation is completed and recovered Set the tool and put the soluble fracturing ball of corresponding size in the wellhead. In the vertical well section, the soluble fracturing ball can fall to the ball seat on the top of the mandrel 2 of the mixing bridge plug under the action of gravity. In the horizontal well section, the soluble fracturing ball can be pushed to the ball on the top of the mandrel 2 of the mixing bridge plug by injecting liquid Seat. After the fracturing ball falls on the ball seat, continue to inject fracturing liquid through the fracturing pump to apply pressure to the ball to achieve the sealing of the ball and the ball seat, so the fracturing liquid will enter through the perforation hole on the casing Strata, fracturing the stratum. When the total amount of designed proppant is pumped into the stratum, the fracturing construction is completed, and the above steps are repeated until the completion of all stratum transformations.

In the field of bridge plug technology, the seat sealing stroke is the distance that the slip moves relative to the mandrel, that is, the length of the slip exposed by the mandrel after the slip has moved.

The hybrid bridge plug in this embodiment is set at the last position of the whole downhole. When the sealing is completed, the second mandrel is located outside the slippage, as shown in Figure 2; the bridge plug is left in the oil and gas wellbore 13 design Set the depth, then complete the perforating operation and recover the set tool, put the soluble fracturing ball 14 of the corresponding size at the wellhead, and then push the mandrel to move, so that the second mandrel 22 is completely located in the first slip holder limit structure 9 and beyond. At the same time, since the second mandrel 22 and the first joint 10 are made of soluble materials, when the oil and gas well needs to be rebuilt, the second mandrel 22 and the first joint will be dissolved directly, and there is almost no residue The object is at the bottom of the well. Furthermore, the bridge plug is set in a two-stage structure, and the length of the second mandrel 22 is less than or equal to the seating stroke of the hybrid bridge plug; when the sealing of the bridge plug is completed, the clamping force of the slips acts on the first core On the shaft, since the first mandrel is an insoluble material, the reliability of the bridge plug is ensured.

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

Since the conventional bridge plug is provided with an engagement structure in order to match the engagement between the two joints, the length of the entire first joint will reach 1/4 to 1/5 of the length of the mandrel, and the bridge plug is relatively bulky. The first joint adopting the soluble material has high hardness, and the strength requirement of the bridge plug can be achieved without setting a long length, which reduces the weight and length of the bridge plug and improves the convenience of the bridge plug.

In this embodiment, the wristband 11 is made of a soluble material; in this way, the wristband will also be dissolved, and the bridge plug component will not remain in the bottom of the well.

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

In the actual use of the product, multiple bridge plugs will be used together. During the fracturing process, one end of the mandrel in the bridge plug will seal the inner diameter of the mandrel through the sealing ball. When returning, the sealing ball of the lower bridge plug When returning to the sealing position of the bridge plug, the sealing ball will contact the bottom of the lower joint stub, but it will not block the through hole. The well fluid still has a flow channel during the back discharge; the uniform distribution of the through hole ensures that the bridge plug Smooth flow of liquid around. At the same time, since the second mandrel is a soluble material, a plurality of through holes are provided, which increases the contact area of the downhole slurry and the second mandrel, and increases the dissolution speed of the second mandrel.

In this embodiment, the end of the first joint 10 has a planar structure.

The conventional bridge plug is provided with an engagement structure in order to match the engagement between the two joints. The first joint adopting the soluble material does not need to be provided with an engagement structure, which reduces the weight and length of the bridge plug and improves the convenience of the bridge plug.

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

The first joint using soluble materials has a high surface smoothness, a small friction coefficient, and a convenient sealing 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 connector 1 is provided with an interlocking structure, which is convenient for matching with the conventional bridge plug, realizes the overall adaptation and use of the conventional bridge plug, and improves the use range and versatility of the product.

In the description of the present invention, it should be understood that the terms "center", "length", "width", "upper", "lower", "vertical", "horizontal", "top", "bottom", The orientation or positional relationship indicated by "inner" etc. is based on the orientation or positional relationship shown in the drawings, only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, It is constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

In the present invention, unless otherwise clearly specified and defined, the terms "installation", "connection", "connection", "fixation" and other terms should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection , Or integrated; it can be directly connected or indirectly connected through an intermediate medium, it can be the connection between the two elements or the interaction between the two elements. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

In the present invention, unless otherwise clearly specified and defined, the first feature "above" or "below" the second feature may include the first and second features in direct contact, or may include the first and second features Contact not directly but through other features between them. Moreover, the first feature is “above”, “above” and “above” the second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature is "below", "below" and "below" the second feature includes that the first feature is directly below and obliquely below the second feature, or simply means that the first feature is less horizontal than the second feature.

The hybrid bridge plug of the present invention has been described in detail above, and specific examples have been used in this article to explain the principle and implementation of the present invention. The descriptions of the above embodiments are only used to help understand the core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation and application scope. As mentioned above, the content of this specification should not be construed as limiting the present invention.

Claims

A hybrid bridge plug is used for temporarily plugging oil and gas wellbore, which is characterized by comprising a hollow core shaft (2) and a rubber cylinder (7), the rubber cylinder (7) is slidably sleeved on the core shaft (2 ) At the middle of the outer surface of the outer surface, the outer surface of the mandrel (2) is located at one end of the rubber cylinder (7) and is sequentially sleeved with a first cone sleeve (8) and a first slip seat limiting structure (9), one end of the mandrel (2) is sleeved with a first joint (10); the outer surface of the mandrel (2) is located at the other end of the rubber cylinder (7), and a second sleeve is sleeved in sequence A cone sleeve (6) and a push ring (3), 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 holder limiting structure (9), the push ring (3), the second cone sleeve (6), the first joint (10) and the first Both joints (1) are made of composite materials; the mandrel (2) includes a first mandrel (21) and a second mandrel (22) that are in contact with each other, and the second mandrel (22) In contact with the first joint (10), the length of the second mandrel (22) is less than or equal to the sealing stroke of the hybrid bridge plug. When the hybrid bridge plug completes the sealing, the The second mandrel (22) is located outside the slip (9), and the second mandrel (22) and the first joint (10) are made of soluble materials.
The hybrid bridge plug according to claim 1, wherein the length of the first joint (10) is between 1/5 and 1/6 of the length of the mandrel (2).
The hybrid bridge plug according to claim 1 or 2, characterized in that a second slip seat limiting structure (4) is sleeved on the mandrel (2), and the second slip seat limiting structure (4) Located between the second cone sleeve (6) and the push ring (3); on the second slip holder limit structure (4) and the first slip holder limit structure (9) Set the limit slip (5).
The hybrid bridge plug according to claim 3, wherein the first joint (10) is provided with a wristband (11), the wristband (11) and the first joint (10) Threaded connection.
The hybrid bridge plug according to claim 4, characterized in that the bracelet (11) is made of a soluble material.
The hybrid bridge plug according to claim 1 or 2, wherein the second mandrel (22) is provided with a through hole in the radial direction.
The hybrid bridge plug according to claim 6, wherein there are a plurality of through holes.
The hybrid bridge plug according to claim 7, wherein a plurality of the through holes are evenly distributed in the circumferential direction of the second mandrel (22).
The hybrid bridge plug according to claim 1 or 2, wherein the end of the first joint (10) has a planar structure.
The hybrid bridge plug according to claim 1 or 2, wherein the outer surface roughness Ra of the first mandrel (21) is less than 6.3.