Double cup slip type bridge plug

Abstract

This utility model belongs to the technical field of downhole plugging tools for coalbed methane extraction. The purpose is to provide a reliable, tight-sealing, and cost-effective double-cup type slip bridge plug. The technical solution includes a central tube, an anchoring mechanism, and a sealing mechanism. Both the anchoring and sealing mechanisms are fitted outside the central tube. It also includes an upper cup-shaped rubber sleeve and a lower cup-shaped rubber sleeve. Both the upper and lower cup-shaped rubber sleeves are cup-shaped with a circular bottom and conical sidewalls. The diameter of their edges is between the diameter of their bottom and the inner diameter of the well casing. The bottoms of the upper and lower cup-shaped rubber sleeves are opposite each other and fitted outside the central tube. The sealing mechanism is a rubber sleeve, with the upper cup-shaped rubber sleeve installed above the lower cup-shaped rubber sleeve and the lower cup-shaped rubber sleeve installed below it. The anchoring mechanism includes an upper cone, an upper slip, a lower cone, and a lower slip. The upper cone is embedded in the upper slip, and the lower cone is embedded in the lower slip. This utility model is used for temporary or long-term downhole plugging.

Description

Technical Field

[0001] This utility model relates to a double-cup type slip bridge plug, belonging to the technical field of downhole sealing tools for coalbed methane extraction. Background Technology

[0002] In oil exploration and development, sealing is a common and crucial operational procedure. Depending on the specific operational objective, relevant producing layers need to be temporarily or permanently sealed to accurately assess their characteristics and scientifically and rationally formulate and implement development plans. This includes stratified oil testing, stratified fracturing, stratified acidizing, stratified water injection, stratified oil production, and sealing of cross-contaminating, water-bearing, dry, and abandoned layers. Compared to oil and gas wells, coalbed methane wells are shallower, and a single coalbed methane well typically contains multiple producing layers. Especially near water-conducting faults and adjacent peak formations, producing layers can easily connect with aquifers during fracturing, making it difficult for the fluid level inside the wellbore to drop.

[0003] Taking the Qinshui block in Jincheng City, Shanxi Province as an example, the target formations for coalbed methane wells are No. 3, No. 9, and No. 15. Some wells, after years of drainage, have consistently maintained an average water production of 20 m³ / s. 3 / d, and the liquid level drops slowly, so the gas production can never reach the expected level. After analyzing the geological data, it was found that the top and bottom plates of the No. 3 coal seam are mainly mudstone or silty mudstone, with weak water-bearing and water-conducting capacity, which has little impact on coalbed methane extraction. However, the top plate of the No. 15 coal seam has a stable K2 limestone layer with well-developed fractures and strong local water-bearing capacity. Water can flow into the No. 15 coal seam along faults or fractures, which will have an adverse effect on drainage and pressure reduction of the No. 15 coal seam. In addition, the bottom plate of the No. 15 coal seam is about 15-20m away from the Fengfeng Formation. The Fengfeng Formation is mainly composed of limestone with many fractures, developed karst caves, and possible underground rivers, and has abundant water content. The well pocket after drilling is generally 40-50m deep, and the Fengfeng Formation has been exposed. The groundwater in the Fengfeng Formation may flow into the casing through the perforation section along the gap between the production casing and the cement sheath, which will eventually make it difficult for the liquid level in the wellbore to drop. Therefore, it is necessary to seal the lower producing layer and extract the coalbed methane from the upper producing layer.

[0004] Slip bridge plugs are commonly used for sealing. The structure of slip bridge plugs generally uses slip anchoring and rubber sleeve sealing. However, the rubber sleeve is usually cylindrical. It relies on the compression of both sides to make the middle bulge and tightly adhere to the casing wall to achieve a sealing effect. However, the downhole conditions are complex. Under long-term pressure or corrosive fluid, the rubber sleeve may not seal properly or even fail. Therefore, it is necessary to design a sealing tool with more reliable performance and reasonable cost. Utility Model Content

[0005] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide a double cup type slip bridge plug that is structurally reliable, tightly sealed, and reasonably cost-effective.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a double-cup type slip bridge plug, comprising a central tube, an anchoring mechanism, and a sealing mechanism, both of which are fitted outside the central tube. It also includes an upper cup-shaped rubber sleeve and a lower cup-shaped rubber sleeve, both of which are cup-shaped with a circular bottom and conical sidewalls. The diameter of their edges is between the diameter of their bottom and the inner diameter of the well casing. The bottoms of the upper and lower cup-shaped rubber sleeves are opposite each other and fitted outside the central tube.

[0007] Optionally, the upper cup-shaped rubber tube and the lower cup-shaped rubber tube may also be grooved with raised edges.

[0008] Preferably, the sealing mechanism is a rubber cylinder, with an upper cup-shaped rubber cylinder installed above the rubber cylinder and a lower cup-shaped rubber cylinder installed below the rubber cylinder.

[0009] Preferably, an upper spacer ring is provided between the rubber tube and the upper cup-shaped rubber tube, an upper pressure ring is provided above the upper cup-shaped rubber tube, and the bottom of the upper cup-shaped rubber tube is clamped between the upper pressure ring and the upper spacer ring; A lower partition ring is provided between the rubber tube and the lower cup-shaped rubber tube, and a lower pressure ring is provided below the lower cup-shaped rubber tube. The bottom of the lower cup-shaped rubber tube is clamped between the lower pressure ring and the lower partition ring.

[0010] Preferably, the anchoring mechanism includes an upper cone, an upper slip, a lower cone, and a lower slip. The upper cone is positioned above the upper pressure ring, the upper slip is positioned above the upper cone, and the upper cone is embedded in the upper slip. The lower cone is positioned below the lower pressure ring, the lower slip is positioned below the lower cone, and the lower cone is embedded in the lower slip.

[0011] Preferably, the upper and lower cup-shaped rubber cylinders are made of rubber with built-in metal support and an anti-extrusion mesh layer.

[0012] Compared with the prior art, the present invention has the following beneficial effects.

[0013] This utility model includes an upper cup-shaped rubber sleeve and a lower cup-shaped rubber sleeve. Due to their own shapes, the upper and lower cup-shaped rubber sleeves are expanded and tightly adhere to the inner wall of the well casing under the action of the upper and lower flow pressure, so as to reliably seal the well casing. It has the characteristics of becoming tighter and better sealing as the pressure increases, and has stable performance and good sealing effect. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the structure of this utility model.

[0016] Figure 2 This is a diagram showing the usage state of this utility model.

[0017] In the diagram: 1 is the central tube, 2 is the upper cup-shaped rubber tube, 3 is the lower cup-shaped rubber tube, 4 is the rubber tube, 5 is the upper spacer ring, 6 is the upper pressure ring, 7 is the lower spacer ring, 8 is the lower pressure ring, 9 is the upper cone, 10 is the upper slip, 11 is the lower cone, and 12 is the lower slip. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described in conjunction with the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model.

[0019] It should be noted that the structures, proportions, sizes, etc. shown in the accompanying drawings of this specification are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which this utility model can be implemented. Therefore, they have no substantial technical significance. Any modification to the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed in this utility model, provided that it does not affect the effects and purposes that this utility model can produce. It should be noted that in this specification, relational terms such as "first" and "second" are only used to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0020] The present invention provides the following embodiments.

[0021] like Figure 1 As shown, this utility model discloses a double-cup type slip bridge plug, including a central tube 1, an anchoring mechanism, and a sealing mechanism. The anchoring mechanism and the sealing mechanism are both fitted outside the central tube 1. It also includes an upper cup-shaped rubber sleeve 2 and a lower cup-shaped rubber sleeve 3. The upper cup-shaped rubber sleeve 2 and the lower cup-shaped rubber sleeve 3 are both cup-shaped with a circular bottom and a conical side wall. The diameter of their edges is between the diameter of their bottom and the inner diameter of the well casing. The bottom of the upper cup-shaped rubber sleeve 2 is opposite to the bottom of the lower cup-shaped rubber sleeve 3 and is fitted outside the central tube 1.

[0022] The upper cup-shaped rubber tube 2 and the lower cup-shaped rubber tube 3 can also be grooved with raised edges, or other similar shapes, such as plate-shaped, bowl-shaped, etc.

[0023] The sealing mechanism is a rubber cylinder 4, with an upper cup-shaped rubber cylinder 2 installed above the rubber cylinder 4 and a lower cup-shaped rubber cylinder 3 installed below the rubber cylinder 4.

[0024] An upper partition ring 5 is provided between the glue tube 4 and the upper cup-shaped glue tube 2, an upper pressure ring 6 is provided above the upper cup-shaped glue tube 2, and the bottom of the upper cup-shaped glue tube 2 is clamped between the upper pressure ring 6 and the upper partition ring 5. A lower partition ring 7 is provided between the rubber tube 4 and the lower cup-shaped rubber tube 3, and a lower pressure ring 8 is provided below the lower cup-shaped rubber tube 3. The bottom of the lower cup-shaped rubber tube 3 is clamped between the lower pressure ring 8 and the lower partition ring 7.

[0025] The anchoring mechanism includes an upper cone 9, an upper slip 10, a lower cone 11, and a lower slip 12. The upper cone 9 is positioned above the upper pressure ring 6, the upper slip 10 is positioned above the upper cone 9 and is embedded in the upper slip 10, the lower cone 11 is positioned below the lower pressure ring 8, and the lower slip 12 is positioned below the lower cone 11 and is embedded in the lower slip 12.

[0026] The upper cup-shaped rubber cylinder 2 and the lower cup-shaped rubber cylinder 3 are made of rubber with built-in metal support components and an anti-extrusion mesh layer. This type of rubber is an existing material.

[0027] This invention is particularly suitable for well casings that require long-term sealing. The upper cup-shaped rubber sleeve 2 and the lower cup-shaped rubber sleeve 3 in the structure reliably seal the well casing under the action of the upper and lower flow pressure. It has the characteristics of becoming tighter and better sealing as pressure increases, and it has stable performance and good sealing effect.

[0028] The core of this utility model is the upper cup-shaped rubber tube 2 and the lower cup-shaped rubber tube 3. They can be in the form of a permanent bridge plug, or they can include an unsealing mechanism to become a removable bridge plug, or they can be made of soluble material to become a soluble bridge plug.

[0029] like Figure 2 As shown, this utility model can be used to seal the No. 15 coal seam that has a water-bearing layer, realize the effective extraction of coalbed methane in the upper No. 3 and No. 9 coal seams, and increase the gas production of coalbed methane wells. It can also be used for stratified oil testing, stratified fracturing, stratified acidizing, stratified water injection, stratified oil production, as well as sealing cross-flowing layers, water layers, dry layers, abandoned layers, etc.

[0030] This utility model achieves Figure 2 The process steps for sealing the middle are as follows. In this step, a ball-type bridge plug is used.

[0031] S1. Preparations before operation: Select coalbed methane wells where the liquid level is difficult to drop due to the connection of water-conducting faults or the connection of Ordovician limestone water during the fracturing of the lower coal seam as test wells. Before the present invention is put into the well, necessary inspections and pressure tests are carried out on each component on the ground. The construction vehicle is in place, the pulleys and blowout preventer are connected, and the preparations before the bridge plug is lowered are completed.

[0032] S2. Sand Exploration and Sand Removal Operations: Connect three sand exploration tubing pipes to the conventional well with a φ73mm tubing and place them into the wellbore for sand exploration operations. When exploring the sand surface, the sand exploration tubing needs to be pressurized, and the pressure value needs to reach 20KN. If there is sand column and it affects the setting position, a sand shovel and sand sinker pipe need to be installed for sand removal operations.

[0033] S3. Scrapping and Wellbore Clearing Operation: Due to the low mechanical strength of slip-type bridge plugs during setting, scraping operations are required in the set section to remove cement residue, burrs, dead oil, and hard wax from the original casing inner wall. This ensures effective sealing of the casing during bridge plug setting. The descent speed of the scraper must be carefully controlled, not exceeding 25 m / h, and the resistance should not exceed 2 tons to prevent casing deformation from jamming the scraper. After scraping, a φ116mm well gauge should be run to clear the well to the set position to ensure smooth subsequent installation of the bridge plug string.

[0034] S4. Sealing Operation: First, lower the φ114mm model, its setting tool, and tubing string. During the well entry process, strictly control the contact between the model and the derrick / drill platform, while controlling the lowering speed to minimize collisions and impacts between the model and the casing and couplings. After lowering to the setting position, insert a φ38mm steel ball into the tubing and connect the surface pipeline and pump truck. Use the surface pump truck to pressurize and seal the well until the model detaches. Stop pressurizing, raise the tubing string, connect the tubing short section under the string, and lower it into the well. Check for any displacement of the model to determine if the setting is secure.

[0035] S5. Pump commissioning: The inspected oil pump is lowered into the wellbore, the pumping unit is installed on the ground, and the well site is restored to its original state before power is supplied for commissioning to complete the extraction of the upper coalbed methane production layer.

[0036] The following points should be noted in S4: When setting the seal, the setting position should avoid the casing coupling. When pressurizing, the pump truck should pressurize to 8 MPa in first gear, stop the pump and stabilize the pressure for 5 minutes, then slowly pressurize to 12 MPa, stop the pump and stabilize the pressure for 5 minutes, then pressurize to 18 MPa again until the bridge plug disengages. When the oil pipe short section is lowered to probe the bridge plug, the pressure should be increased to 30 kN. No displacement of this utility model indicates that the sealing operation is qualified.

[0037] In S4, after the pump truck pressurizes, the setting tool applies downward pressure to the upper slip 10, causing the upper slip 10 to move downward, which in turn moves the lower cone 9 downward. The lower cone 9 then moves the upper cup-shaped rubber sleeve 2, rubber sleeve 4, lower cup-shaped rubber sleeve 3, and lower cone 11 downward. Simultaneously, the upper slip 10 and lower slip 12 are opened and embedded into the inner wall of the casing for anchoring. Then, the setting tool continues to press down, and the rubber sleeve 4 is squeezed and deformed, pressing against the inner wall of the casing to achieve a seal. Then, the setting tool disengages from the present invention, completing the setting process. After the coalbed methane well resumes normal operation, the upward and downward flow pressure in the wellbore acts on the upper cup-shaped rubber sleeve 2 and lower cup-shaped rubber sleeve 3, squeezing and expanding them towards the center, making the seal more tight and reliable.

[0038] The above description is merely a preferred embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A double cup-type slip bridge plug, comprising a center pipe (1), an anchoring mechanism and a sealing mechanism, the anchoring mechanism and the sealing mechanism are sleeved outside the center pipe (1), characterized in that: It also includes an upper cup-shaped rubber tube (2) and a lower cup-shaped rubber tube (3). The upper cup-shaped rubber tube (2) and the lower cup-shaped rubber tube (3) are both cup-shaped with a circular bottom and a conical side wall. The diameter of their edges is between the diameter of their bottom and the inner diameter of the well casing. The bottom of the upper cup-shaped rubber tube (2) is opposite to the bottom of the lower cup-shaped rubber tube (3) and is fitted outside the central tube (1).

2. A dual cup slip type bridge plug as defined in claim 1, wherein: Both the upper cup-shaped rubber tube (2) and the lower cup-shaped rubber tube (3) are grooved with raised edges.

3. A dual cup slip type bridge plug as claimed in claim 1 or 2, wherein: The sealing mechanism is a rubber tube (4), with an upper cup-shaped rubber tube (2) installed above the rubber tube (4) and a lower cup-shaped rubber tube (3) installed below the rubber tube (4).

4. A dual cup slip-type bridge plug as defined in claim 3, wherein: An upper partition ring (5) is provided between the rubber tube (4) and the upper cup-shaped rubber tube (2), and an upper pressure ring (6) is provided above the upper cup-shaped rubber tube (2). The bottom of the upper cup-shaped rubber tube (2) is clamped between the upper pressure ring (6) and the upper partition ring (5). A lower partition ring (7) is provided between the rubber tube (4) and the lower cup-shaped rubber tube (3), and a lower pressure ring (8) is provided below the lower cup-shaped rubber tube (3). The bottom of the lower cup-shaped rubber tube (3) is clamped between the lower pressure ring (8) and the lower partition ring (7).

5. A dual cup slip type bridge plug as defined in claim 4 wherein: The anchoring mechanism includes an upper cone (9), an upper slip (10), a lower cone (11), and a lower slip (12). The upper cone (9) is positioned above the upper pressure ring (6), the upper slip (10) is positioned above the upper cone (9), and the upper cone (9) is embedded in the upper slip (10). The lower cone (11) is positioned below the lower pressure ring (8), and the lower slip (12) is positioned below the lower cone (11), and the lower cone (11) is embedded in the lower slip (12).

6. A dual cup slip type bridge plug as claimed in claim 1 or 2, wherein: The upper cup-shaped rubber cylinder (2) and the lower cup-shaped rubber cylinder (3) are made of rubber with built-in metal support and anti-extrusion mesh layer.

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