Full breakaway insert shoe

Abstract

The application relates to the technical field of drilling guide shoes, and discloses a full-crushing plug-in type guide shoe which comprises a sleeve, a guide shoe is arranged in the inside of the sleeve, a base layer is arranged in the inside of the bottom end of the guide shoe, a bottom layer damage layer is arranged in the inside of the base layer, a middle layer damage layer is arranged in the inside of the bottom layer damage layer, and a top layer damage layer is arranged in the inside of the middle layer damage layer. The bottom layer damage layer, the middle layer damage layer and the top layer damage layer are designed to be completely crushed under the action of a roller bit, so that the bottom hole diameter and the flow area are expanded, the increased diameter and the flow channel effectively improve the discharge efficiency of rock cuttings, the risk of bottom hole pressure accumulation is reduced, the mud is smooth in the drilling process, and the overall drilling efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of drilling guide shoe technology, specifically a fully fractured insertion guide shoe. Background Technology

[0002] In the extraction of resources such as oil and natural gas, drilling technology is an indispensable and crucial step, and the smooth progress of casing installation is closely related to the design of the guide shoe structure. Traditional guide shoe structures mostly use a single layer of cement or simple mixed materials as the base material, and their main function is to provide support for the bottom of the well. With the increase in drilling depth and the increasing complexity of the extraction environment, the single-layer structure of traditional guide shoes has revealed a series of problems, making it difficult to meet the drilling requirements under complex geological conditions.

[0003] To generate a sufficiently large borehole diameter, larger roller cone bits are generally used for well washing during the second phase of drilling. Using conventional roller cone bits for well washing results in a longer cumulative time required for tripping and well washing. If conventional roller cone bits are used directly for well washing, the cement sheath at the bottom of the guide shoe will be drilled through, resulting in a smaller hole diameter. When drilling to the lower bottom layer later, the annulus at the guide shoe will be pressured due to the small hole diameter, making it difficult to return cuttings.

[0004] Therefore, the present invention provides a fully ruptured insert shoe. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a fully fractured insert-type guide shoe, which solves the problems of long cumulative time required for tripping in and out of the drill string and well washing, and the small diameter of the hole after the cement sheath at the bottom of the guide shoe is drilled through when using conventional roller cone drill bits for well washing, resulting in annular pressure buildup and difficulty in returning cuttings.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: a fully fractured insertable guide shoe, including a sleeve, a guide shoe is disposed inside the sleeve, a base layer is disposed inside the bottom end of the guide shoe, a bottom layer of fracture is disposed inside the base layer, a middle layer of fracture is disposed inside the bottom layer of fracture, and a top layer of fracture is disposed inside the middle layer of fracture. The preparation method of the fully fractured insert shoe includes the following steps; S1. Mix cement with 3-5% polypropylene fiber reinforcing agent at a water-cement ratio of 0.4-0.5, stir evenly, and pour to a thickness of 10-20mm to form the compressive strength of the matrix layer. S2. Prepare the bottom layer material, middle layer material and top layer material, and process the materials; S3. The bottom layer material, the middle layer material and the top layer material are poured sequentially at the bottom of the base layer to form a multi-layer composite fracture layer; S4. Vibrate and compact each layer of material to control the porosity of each layer.

[0007] Preferably, step S1 specifically includes: S1.1. Cement and water shall be mixed evenly at a water-cement ratio of 0.4-0.5 to ensure the fluidity and strength of the cement paste; S1.2 Slowly add 3%-5% polypropylene reinforcing fiber to the cement slurry and stir for 3-5 minutes to make the fiber evenly distributed and enhance the crack resistance of the matrix layer. S1.3 Pour cement to a design thickness of 10-20mm, and use a vibrating table to vibrate and compact it to remove air bubbles and ensure the density of the layer; S1.4 After initial curing for 24 hours, place it in an environment of 60℃ and humidity above 90% for 7 days to achieve the required compressive strength.

[0008] Preferably, the bottom material in step S2 is made of large-diameter round stones with a particle size of 10-14 mm and an irregular shape. The surface of the round stones is cleaned to enhance the adhesion between the round stones and the cement matrix.

[0009] Preferably, the intermediate layer material in step S2 includes medium-sized pebbles, fine sand, and polystyrene particles. The pebbles have a particle size of 6-10 mm, the fine sand has a particle size of 0.1-1 mm, and the material is dried to avoid excessive moisture content.

[0010] Preferably, the top layer material in step S2 is composed of small-diameter aggregates, fine sand and reinforced cement slurry, with the aggregates having a particle size of 3-5 mm and the fine sand having a particle size of 0.1-1 mm.

[0011] Preferably, step S3 specifically includes: S3.1 Mix 10-14mm round stones with cement in a ratio of 1:2 to 2:1 and lay the mixture on the substrate. The thickness of the bottom layer should be controlled at 20-30mm to form the bottom damaged layer. S3.2 Mix 6-10mm round stones, 0.1-1mm fine sand and polystyrene particles in a ratio of 1:1:0.1, and mix with cement in a ratio of 1:1. Lay the mixture on the bottom damaged layer with a thickness of 15-25mm to form the middle damaged layer. S3.3 Mix small aggregates with a particle size of 3-5mm, fine sand with a particle size of 0.1-1mm, and cement in a ratio of 2:1:3. Add 0.1%-0.5% graphene nanosheets during mixing and stir. After stirring evenly, lay the mixture in the middle damaged layer with a thickness of 10-15mm to form the top damaged layer. S3.4 After pouring, preliminary curing is required, with a curing time of 24-36 hours, to ensure that the interlayer bonding force of the bottom, middle and top layers gradually increases during the curing process, and to avoid interlayer separation or slippage during subsequent drilling operations.

[0012] Preferably, the porosity of the underlying damaged layer is controlled at 30%-35%.

[0013] Preferably, the porosity of the middle damaged layer is controlled at 20%-25%.

[0014] Preferably, the porosity of the top damaged layer is controlled at 15%-20%.

[0015] This invention provides a fully fractured insert shoe. It has the following beneficial effects: 1. This invention achieves complete rock cuttings breaking through the action of a roller cone drill bit by designing a bottom layer, a middle layer, and a top layer of broken layers. This expands the bottom hole diameter and flow area, and the increased diameter and flow channels effectively improve the efficiency of cuttings removal, reduce the risk of bottom hole pressure accumulation, ensure smooth mud flow during drilling, and improve overall drilling efficiency.

[0016] 2. This invention employs a mixed design of large-diameter round stones and cement, which enables rapid and effective crushing of the bottom layer under the action of the drill bit. The high crushability of the large-diameter round stones helps to completely break the bottom layer, ensuring that the hole is drilled through and the diameter is increased.

[0017] 3. This invention not only increases the density of the layer by adding fine sand, but also enhances the crushing effect under the action of the drill bit. The fine sand and large-diameter round stones together form a crushed layer structure, which allows the drill bit to uniformly transfer energy when it acts on the bottom layer, thereby preventing the problem of reduced drillability of the guide shoe structure due to the addition of round stones. Attached Figure Description

[0018] Figure 1 This is a perspective view of the present invention; Figure 2 This is a flowchart of the method of the present invention.

[0019] Among them, 1. Sleeve; 2. Guide shoe; 3. Base layer; 4. Bottom damaged layer; 5. Middle damaged layer; 6. Top damaged layer. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please see the appendix Figure 1 The present invention provides a fully fractured insert shoe, including a sleeve 1, a shoe 2 is disposed inside the sleeve 1, a base layer 3 is disposed inside the bottom end of the shoe 2, a bottom layer 4 is disposed inside the base layer 3, a middle layer 5 is disposed inside the bottom layer 4, and a top layer 6 is disposed inside the middle layer 5. Specifically, the guide shoe 2 is installed at the bottom of the casing 1 to guide the entire casing string smoothly into the bottom of the wellbore, helping to reduce friction during casing running. Inside the guide shoe 2, there is a matrix layer 3, which serves as the base for the bottom damaged layer 4, the middle damaged layer 5, and the top damaged layer 6, while preventing damage during entry into the wellbore and providing sufficient pressure resistance. The placement of the bottom damaged layer 4, the middle damaged layer 5, and the top damaged layer 6 allows them to transmit drill bit energy laterally and laterally after contacting the roller cone bit, causing the bottom damaged layer 4, the middle damaged layer 5, and the top damaged layer 6 to break sequentially. This crushes and destroys the cement sheath not covered by the roller cone bit, completely breaking the bottom and ensuring an increase in the drilling area, thereby increasing the flow area. This solves the problem of annular pressure buildup and difficulty in cuttings return caused by a small borehole diameter at the guide shoe 2.

[0022] Please see the appendix Figure 2 The preparation method of the fully fractured insert shoe includes the following steps; S1. Mix cement with 3-5% polypropylene fiber reinforcing agent at a water-cement ratio of 0.4-0.5, stir evenly, and pour to a thickness of 10-20mm to form the compressive strength of the matrix layer. S2. Prepare the bottom layer material, middle layer material and top layer material, and process the materials; S3. The bottom layer material, the middle layer material and the top layer material are poured sequentially at the bottom of the base layer to form a multi-layer composite fracture layer; S4. Vibrate and compact each layer of material to control the porosity of each layer; Specifically, cement is mixed with 3-5% polypropylene fiber reinforcing agent at a water-cement ratio of 0.4-0.5. This water-cement ratio ensures the fluidity and strength of the cement matrix while allowing the polypropylene fibers to be evenly distributed in the cement slurry. Ordinary Portland cement is selected because it has good compatibility with polypropylene fibers. 3%-5% of the polypropylene fibers are slowly added to the cement slurry, and the mixture is stirred using a mechanical mixer for 3-5 minutes to ensure even fiber distribution. The polypropylene fibers enhance the crack resistance of the cement matrix, preventing crack propagation and thus improving the overall strength and durability of the matrix layer. The uniformly mixed cement mixture is then poured to a predetermined thickness of 10-20 mm to form the matrix layer. The matrix layer is then compacted using a vibrating table to remove air bubbles and ensure its density and uniformity. The vibration time is controlled at 1-2 minutes to avoid excessive vibration that could lead to uneven fiber distribution. After pouring, the matrix layer needs to undergo preliminary curing for 24 hours. After curing, the matrix layer is placed at a temperature of [temperature missing]. The base layer material is laid on the substrate layer, with a pouring thickness controlled at 20-30mm, forming the bottom fractured layer. During pouring, the base layer material is leveled using manual leveling tools to ensure a uniform surface. After pouring, light vibration is used to ensure material compaction, controlling the porosity of the base layer material to 30%-35%. After the base layer has initially cured, the intermediate layer material is laid on top of it, with a pouring thickness controlled at 15-25mm. The intermediate layer material consists of a uniform mixture of pebbles, fine sand, and polystyrene particles in a specific ratio, which is then evenly laid on top of the base layer. Moderate compaction forms the intermediate fractured layer, controlling the porosity at 20%-25%. The presence of polystyrene particles effectively buffers stress during drilling, preventing premature interlayer damage. After the intermediate layer has initially cured, the top layer material is laid on top of it, with a pouring thickness controlled at 10-15mm. Graphene nanosheets are added to the cement slurry of the top layer material, forming a highly sealing and compressive-resistant layer after curing. Moderate vibration is used after pouring to ensure the compactness of the top layer material and prevent air bubbles. The porosity is controlled at 15%-20% through vibration compaction. After the bottom, middle, and top layers are poured, preliminary curing is performed for 24-36 hours. Preliminary curing ensures good bonding between the layers, enhances interlayer adhesion, and prevents interlayer separation or slippage during subsequent drilling operations. Example 1;

[0023] Implementation steps; Preparation of cement grout: Take ordinary Portland cement and mix it with mud and water at a water-cement ratio of 0.45 to ensure that the cement grout has appropriate fluidity so that it can be poured evenly and meet the compressive strength requirements. Addition and mixing of the reinforcing agent: Slowly add the polypropylene fiber reinforcing agent during mixing, at a dosage of 4% of the cement weight. Mix with a mechanical mixer for 4 minutes to ensure uniform distribution of the polypropylene fibers in the cement paste. Polypropylene fibers enhance the crack resistance of cement, preventing rapid crack propagation under high pressure. Cement grout is poured into the substrate layer to a thickness of 15mm. The substrate layer is then vibrated for 1 minute using a vibrating table to compact it, removing air bubbles from the mixture and preventing structural voids caused by residual air bubbles during pouring. This ensures a uniform and dense substrate layer. After pouring, the substrate layer needs to be pre-cured for 24 hours to form a layer with initial hardness.

[0024] Preparation and treatment of the middle and top layer materials: For the bottom layer material: irregular round stones with a particle size of 12mm are selected, cleaned to enhance adhesion to cement, and mixed with cement at a 1:2 ratio. The thickness of the bottom layer material is controlled at 25mm to form an effective fracturing layer, providing initial fracturing support for the drill bit. Intermediate layer material: 8mm diameter pebbles, 0.5mm fine sand, and polystyrene particles are used in a 1:1:0.1 ratio. The addition of polystyrene particles creates a buffer zone in the intermediate layer. This mixture is stirred evenly with cement in a 1:1 ratio, with the thickness controlled at 20mm. Top layer material: The top layer material is a mixture of small aggregates (4mm particle size), fine sand, and reinforced cement paste in a 2:1:3 ratio, with 0.3% graphene nanosheets added. Graphene helps improve the compressive strength and sealing properties of the cement. The thickness of the top layer material is 12mm. Layer-by-layer pouring and compaction: The bottom, middle and top layers of material are laid on the base layer in sequence. After each layer is poured, it is compacted by light vibration on a vibrating table to ensure that the material is evenly distributed and dense. The vibration time for the bottom and middle layers is 1 minute and the vibration time for the top layer is 30 seconds. After all layers are poured, a preliminary curing process is carried out for 24 hours. The curing process ensures good bonding between the layers and avoids interlayer slippage or separation. Summarize; The guide shoe in this example exhibits excellent compressive strength, interlayer bonding, and sealing performance. Each layer of material plays a role in breaking down, cushioning, and sealing within the structure, ensuring the guide shoe remains stable under high pressure. Tests show that the recommended component ratios and process parameters can effectively improve the performance of multilayer structures, ensuring their adaptability and durability under complex geological conditions. Example 2;

[0025] Implementation steps; Cement slurry preparation: Cement and water are mixed at a water-cement ratio of 0.35 to form a cement slurry with slightly lower fluidity. The reduced fluidity may affect the uniformity of the substrate layer. Addition and mixing of reinforcing agent: The content of polypropylene fiber reinforcing agent is controlled at 2.5% of the cement weight, and mechanically mixed for 3 minutes. A lower content of polypropylene fiber reduces the crack-resistant reinforcing effect, resulting in a decrease in crack resistance. Pouring and compaction: Pour the cement slurry to the base layer, with a thickness controlled at 10mm, and use a vibrating table to perform light vibration for 30 seconds to remove air bubbles; Curing and maintenance: After initial curing for 24 hours, place the substrate layer in an environment of 50℃ and 80% humidity for 5 days. The curing time and humidity are too low, which may result in the substrate layer not meeting the strength requirements. Preparation and treatment of bottom, middle and top layer materials: Bottom layer material: 10mm pebbles are mixed with cement in a 1:2 ratio. A low mixing ratio will reduce the adhesion. The thickness is controlled at 20mm. Intermediate layer material: Select 6mm round stones, 0.2mm fine sand and polystyrene particles in a ratio of 1:1:0.05, mix with cement in a ratio of 1:1.5, and the thickness is 15mm. Top layer material: 3mm fine aggregate, fine sand, and cement slurry are mixed in a 1:1:2 ratio, with 0.05% graphene nanosheets added. Due to the low graphene content, the sealing performance of the top layer material is somewhat reduced, and the thickness is controlled at 10mm. Layer-by-layer pouring and compaction: The bottom, middle and top layers of material are poured sequentially on top of the base layer, with each layer vibrating for 30 seconds. Curing: After curing for 24 hours, the interlayer bonding force is weak, resulting in a loose structure of the shoe during testing, which is prone to delamination and poor sealing. Summarize; In this embodiment, the material and process parameters of each layer are below the recommended range, resulting in insufficient compressive strength and sealing performance of the guide shoe. During high-pressure testing, the lack of adequate crack resistance and sealing makes the guide shoe prone to crack propagation and interlayer delamination. Example 3;

[0026] Implementation steps; Matrix layer preparation; Cement slurry preparation: Cement and water are mixed at a water-cement ratio of 0.55 to form a highly fluid cement slurry, which can easily cause the fibers to sink during pouring. Addition and mixing of reinforcing agent: Add polypropylene fiber reinforcing agent at a content of 5.5% of the cement weight. Extend the mixing time to 5 minutes; over-mixing can easily cause the fibers to clump together. Pouring and compaction: The pouring thickness is 20mm, and the vibrating table is subjected to high-intensity vibration for 2 minutes. The compaction is relatively high, but some fibers may re-aggregate during the vibration process. Curing and maintenance: Initial curing for 24 hours, followed by curing the substrate layer in an environment of 70℃ and 95% humidity for 10 days; Preparation and treatment of bottom, middle and top layer materials: Bottom layer material: 14mm diameter round stones are mixed with cement in a 1:1 ratio, with a thickness of 30mm. The thickened bottom layer makes the structure more compact.

[0027] Intermediate layer material: 10mm coarse stones, 1mm fine sand and polystyrene particles are mixed in a ratio of 1:1:0.2 and mixed with cement in a ratio of 1:0.8. The thickness is 25mm.

[0028] Top layer material: A mixture of 5mm fine aggregate, fine sand, and cement slurry in a 3:1:4 ratio, with 0.6% graphene nanosheets added, forming a 15mm thick layer. The high density and high content of graphene nanosheets contribute to a superior sealing effect. Layer-by-layer pouring and compaction: After each layer of material is poured, it is treated with a high-frequency vibration table for 2 minutes, 1 minute and 30 seconds respectively. Curing: The curing time was extended to 36 hours, and it subsequently showed high compressive strength in the test, but the excessive density affected the stress buffering effect. Summarize; In this embodiment, the component ratio and process parameters exceeding the recommended range caused local aggregation problems in the shoe. The excessive density of the top layer led to uneven stress transmission. Although the compressive strength and sealing performance were improved, the excessive density resulted in uneven stress release in the structure, making it impossible to completely break down and expand the pore area.

[0029] Working principle: The guide shoe 2 is installed inside the bottom end of the casing 1. The guide shoe 2 guides the entire casing string smoothly into the bottom of the wellbore, helping to reduce friction during casing installation. When the guide shoe 2 reaches the bottom of the wellbore, the roller cone bit is inserted into the casing 1 and comes into contact with the bottom damaged layer 4, the middle damaged layer 5, and the top damaged layer 6. The roller cone bit is then used to break the top damaged layer 6 and gradually break the middle damaged layer 5. The middle layer material has a suitable structure; the elasticity of the polystyrene particles makes this layer resistant to drilling. When subjected to head impact or formation pressure, it can effectively buffer and avoid stress concentration. At the same time, it allows the large-diameter round stones in the bottom damaged layer 4 to transfer drill bit energy laterally and laterally under the action of the roller cone drill bit. This enables the roller cone drill bit to completely destroy the bottom damaged layer 4, the middle damaged layer 5, and the top damaged layer 6. It also squeezes and destroys the cement sheath not covered by the roller cone drill bit, completely crushing the bottom and ensuring that the drilling area is expanded, thereby increasing the flow area. This solves the problem of annular pressure buildup and difficulty in cuttings return at the guide shoe 2 due to the small hole diameter.

[0030] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A fully shattering insert shoe, comprising a sleeve (1), characterized in that; The sleeve (1) is provided with a guide shoe (2), the bottom end of the guide shoe (2) is provided with a base layer (3), the base layer (3) is provided with a bottom damaged layer (4), the bottom damaged layer (4) is provided with a middle damaged layer (5) from the inside, and the middle damaged layer (5) is provided with a top damaged layer (6).

2. A method for preparing a fully fractured insert shoe, comprising the fully fractured insert shoe according to any one of claims 1, characterized in that, Includes the following steps; S1. Mix cement with 3-5% polypropylene fiber reinforcing agent at a water-cement ratio of 0.4-0.5, stir evenly, and pour to a thickness of 10-20mm to form the compressive strength of the matrix layer. S2. Prepare the bottom layer material, middle layer material and top layer material, and process the materials; S3. The bottom layer material, the middle layer material and the top layer material are poured sequentially at the bottom of the base layer to form a multi-layer composite fracture layer; S4. Vibrate and compact each layer of material to control the porosity of each layer.

3. The method for preparing the fully fractured insert shoe according to claim 2, characterized in that, Step S1 specifically includes: S1.

1. Cement and water shall be mixed evenly at a water-cement ratio of 0.4-0.5 to ensure the fluidity and strength of the cement paste; S1.2 Slowly add 3%-5% polypropylene reinforcing fiber to the cement slurry and stir for 3-5 minutes to make the fiber evenly distributed and enhance the crack resistance of the matrix layer. S1.3 Pour cement to a design thickness of 10-20mm, and use a vibrating table to vibrate and compact it to remove air bubbles and ensure the density of the layer; S1.4 After initial curing for 24 hours, place it in an environment of 60℃ and humidity above 90% for 7 days to achieve the required compressive strength.

4. The method for preparing the fully fractured insert shoe according to claim 2, characterized in that, In step S2, the bottom material is made of large-diameter round stones with a particle size of 10-14 mm and an irregular shape. The surface of the round stones is cleaned to enhance the adhesion between the stones and the cement matrix.

5. The method for preparing the fully fractured insert shoe according to claim 2, characterized in that, The intermediate layer material in step S2 includes medium-sized pebbles, fine sand, and polystyrene particles. The pebbles have a particle size of 6-10 mm, the fine sand has a particle size of 0.1-1 mm, and the material is dried to avoid excessive moisture content.

6. The method for preparing the fully fractured insert shoe according to claim 2, characterized in that, The top layer material in step S2 consists of small-diameter aggregates, fine sand, and reinforced cement slurry. The aggregates have a particle size of 3-5 mm, and the fine sand has a particle size of 0.1-1 mm.

7. The method for preparing a fully fractured insert shoe according to claim 2, characterized in that, Step S3 specifically includes: S3.1 Mix 10-14mm round stones with cement in a ratio of 1:2 to 2:1 and lay the mixture on the substrate. The thickness of the bottom layer should be controlled at 20-30mm to form the bottom damaged layer. S3.2 Mix 6-10mm round stones, 0.1-1mm fine sand and polystyrene particles in a ratio of 1:1:0.1, and mix with cement in a ratio of 1:

1. Lay the mixture on the bottom damaged layer with a thickness of 15-25mm to form the middle damaged layer. S3.3 Mix small aggregates with a particle size of 3-5mm, fine sand with a particle size of 0.1-1mm, and cement in a ratio of 2:1:

3. Add 0.1%-0.5% graphene nanosheets during mixing and stir. After stirring evenly, lay the mixture in the middle damaged layer with a thickness of 10-15mm to form the top damaged layer. S3.4 After pouring, preliminary curing is required, with a curing time of 24-36 hours, to ensure that the interlayer bonding force of the bottom, middle and top layers gradually increases during the curing process, and to avoid interlayer separation or slippage during subsequent drilling operations.

8. The method for preparing the fully fractured insert shoe according to claim 7, characterized in that, The porosity of the underlying damaged layer is controlled at 30%-35%.

9. The method for preparing the fully fractured insert shoe according to claim 7, characterized in that, The porosity of the middle damaged layer is controlled at 20%-25%.

10. The method for preparing a fully fractured insert shoe according to claim 7, characterized in that, The porosity of the top damaged layer is controlled at 15%-20%.

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