Hydraulic fracturing borehole sealing device and method of use

Abstract

The application discloses a hydraulic fracturing borehole sealing device and a use method. The device comprises a grouting pipe, an inner cylinder and an outer pipe body, the inner cylinder is arranged in the outer pipe body, and rotation cooperation is realized through a rotating mechanism and is locked by a locking mechanism. The lower end of the grouting pipe is integrally connected with a pipe orifice, extends into a fixed pipe and extends into the inner cylinder, and grout is injected. The side walls of the inner cylinder and the outer pipe body are respectively provided with a first discharge port and a second discharge port, alignment or misalignment is realized through relative rotation, and the grout is controlled to enter a borehole or the outlet is closed. The locking mechanism comprises a locking block and a clamping block, the top of the inner cylinder is provided with an arc-shaped mounting groove and a clamping groove, the locking block is clamped with the clamping block and the outer pipe body, and the inner cylinder can rotate after being unlocked. The fixed pipe is connected with the inner cylinder through a horn-shaped connecting plate. The application ensures size stability through integrated design, improves sealing effect through accurate grouting, is simple to operate, is suitable for complex geological conditions, is suitable for borehole sealing operation in the fields of coalbed gas exploitation, shale gas exploitation and the like, and has the advantages of high efficiency, environmental protection and economy.

Description

Technical Field

[0001] This invention relates to the field of hydraulic fracturing drilling technology, specifically to a hydraulic fracturing drilling sealing device and its usage method. Background Technology

[0002] Hydraulic fracturing technology, as an important technology in oil and gas field development and geological engineering, has been widely applied in coalbed methane extraction, shale gas extraction, and formation enhancement. In this process, borehole sealing is a crucial step in ensuring construction quality. The main purpose of sealing is to prevent high-pressure fluid leakage, ensure the safety and stability of the borehole, prevent damage to the surrounding formation, and meet environmental protection and regulatory requirements.

[0003] In existing technologies, such as the downhole hydraulic fracturing borehole grouting and sealing device mentioned in Chinese Patent Publication No. CN115492550B, the design suffers from increased volume. This structure often expands in size during the sealing process due to grouting pressure, limiting its applicability in narrow boreholes and increasing construction difficulty. Many traditional sealing devices struggle to maintain stability during the grouting process under complex geological conditions, especially in fractured formations. Uneven grout distribution leads to decreased sealing effectiveness and increases the likelihood of secondary construction. Furthermore, existing devices have poor adaptability to borehole location and geological conditions. Sealing effectiveness is often unsatisfactory at different depths, angles, and fracture structures. For example, some devices are prone to failure in formations with large borehole dip angles or soft topsoil.

[0004] To better meet actual construction needs, the sealing device needs to have the following characteristics: maintain volume stability during construction to avoid deformation or volume increase due to operating pressure; optimize device structure, simplify operation procedures, and reduce the difficulty of operation for construction personnel; adapt to various geological conditions, especially in environments with developed fissures and complex formation pressure, and still have good sealing effect; have flexible adjustment capabilities during grouting to ensure that mortar can accurately fill fissures and achieve uniform distribution. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to solve the above problems and provide a hydraulic fracturing borehole sealing device and a method of using it.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A hydraulic fracturing borehole sealing device includes a grouting pipe, an inner cylinder, and an outer pipe body; the inner cylinder is disposed inside the outer pipe body, and the inner cylinder and the outer pipe body are rotatably engaged and locked by a locking mechanism;

[0008] The inner cylinder has a fixed pipe at its inlet end; the lower end of the grouting pipe has an integral opening that extends into the inner cylinder and injects mortar into it; the inner cylinder has a first outlet on its side wall and the outer pipe has a second outlet on its side wall; the first outlet and the second outlet are aligned or misaligned by rotation between the inner cylinder and the outer pipe, allowing the mortar to enter the borehole through the second outlet or to close the grouting outlet.

[0009] Furthermore, the locking mechanism includes a locking block and a locking block. The top of the inner cylinder is provided with multiple circumferentially distributed mounting grooves, and a locking groove is provided on one side of the mounting groove. The locking block is located in the mounting groove, and one end of the locking block is engaged with the locking block located in the locking groove, while the other end is engaged with the inner wall of the outer tube. When the locking block is removed, the locking block is separated from the outer tube, and the inner cylinder and the outer tube can rotate at this time.

[0010] Furthermore, the mounting groove is arc-shaped.

[0011] Furthermore, the card block and the card slot have a separable snap-fit ​​structure.

[0012] Furthermore, the fixed tube and the inner cylinder are connected by a connecting plate, which is trumpet-shaped, with the small end connected to the fixed tube and the large end connected to the inner wall of the inner cylinder.

[0013] Furthermore, the first discharge port and the second discharge port are the same or similar in size to ensure uniform mortar output.

[0014] A method of using the hydraulic fracturing borehole sealing device as described above includes the following steps:

[0015] S1. Adjust and install the inner cylinder and outer tube to align the first discharge port with the second discharge port, and lock the inner cylinder and outer tube.

[0016] S2. Insert the grouting pipe into the fixed pipe, ensuring that the pipe opening is aligned with the inside of the inner cylinder;

[0017] S3. The hydraulic fracturing borehole sealing device is hoisted into the borehole to the target depth.

[0018] S4. Rotate the outer tube and adjust the second discharge port until it is aligned with the formation fracture.

[0019] S5. Inject mortar through the grouting pipe, so that the mortar enters the fixed cylinder and fills the formation fissures evenly through the first discharge port and the second discharge port;

[0020] S6. After grouting is completed, release the locking block from the slot, rotate the inner cylinder to misalign the first and second discharge ports, and remove the device after the mortar has solidified.

[0021] Furthermore, in step S6, the top of the outer tube is fixed to prevent it from sliding, while the inner cylinder is rotated to adjust the direction of the first discharge port, thereby stopping the grouting.

[0022] The beneficial effects of this invention are as follows:

[0023] This invention provides a hydraulic fracturing borehole sealing device and its usage method. Compared with existing technologies, it has significant advantages in solving technical problems such as device volume stability, insufficient sealing effect, and operational complexity. Specific beneficial effects are as follows:

[0024] 1. Excellent dimensional stability, adaptable to narrow drilling environments.

[0025] Existing hydraulic fracturing borehole sealing devices often experience volume expansion due to pressure during high-pressure grouting, limiting their applicability in narrow boreholes. This invention addresses this issue by integrating the grouting pipe, inner cylinder, outer pipe, and connecting plate into a single design. Combined with the robust support of the fixed pipe and the structural optimization of the trumpet-shaped connecting plate, this ensures dimensional stability of the device during high-pressure grouting. The inner cylinder and outer pipe are tightly coupled through a rotating and locking mechanism, preventing deformation caused by pressure. This dimensional stability allows the device to adapt to smaller diameter boreholes or space-constrained construction scenarios, significantly broadening its application range. It is particularly suitable for deep drilling operations under complex geological conditions, reducing construction limitations caused by device size.

[0026] 2. Precise grouting enhances sealing effect.

[0027] In environments with well-developed fissures or complex geological conditions, traditional sealing devices often suffer from poor sealing results due to uneven grouting, easily leading to mortar leakage or insufficient fissure filling. This invention utilizes a first discharge port on the inner cylinder sidewall and a second discharge port on the outer pipe sidewall, achieving precise alignment of the discharge ports through the relative rotation of the inner and outer pipes. The arc-shaped discharge ports and their similar size ensure uniform mortar flow, effectively filling formation fissures and preventing uneven mortar distribution or localized blockages. A locking mechanism further ensures the stability of the discharge port alignment, preventing misalignment caused by vibration or pressure during grouting. This precise grouting capability significantly improves sealing quality, reduces the possibility of secondary construction, and meets environmental protection and regulatory requirements.

[0028] 3. Simple operation, reducing construction difficulty

[0029] Traditional sealing devices are complex to operate, especially in complex geological conditions, where operators struggle to achieve precise grouting through simple adjustments. The rotating and locking mechanisms of this invention greatly simplify the operation. Operators can adjust the position of the second outlet by simply rotating the outer tube, aligning it with formation fissures. The locking blocks and latching structures of the locking mechanism facilitate quick locking and releasing, making operation intuitive and efficient. The clearly defined steps in the usage method (adjusting the outlet, injecting mortar, and staggered closing) further reduce construction difficulty, allowing for rapid adaptation even in inclined boreholes or formations with well-developed fissures. Furthermore, the device has a compact overall structure, is lightweight, and simplifies hoisting and removal, significantly improving construction efficiency and reducing labor costs.

[0030] 4. Wide range of environmental adaptability

[0031] This invention, through its flexible discharge port adjustment mechanism and stable structural design, can adapt to various geological conditions, including drilling environments with different depths, angles, and fracture structures. Whether in soft roofs, fractured strata, or high-pressure formations, the device maintains stable sealing performance. The flared connecting plate enhances the connection strength between the inner cylinder and the fixed pipe, ensuring the reliability of the device under complex stress environments. Simultaneously, the modular design of the device facilitates maintenance and assembly, adapting to the needs of different construction scenarios and reducing the cost of equipment replacement or adjustment due to changes in geological conditions.

[0032] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0033] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0034] Figure 1 This is a cross-sectional view of the hydraulic fracturing borehole sealing device of the present invention.

[0035] Figure 2 This is a schematic diagram of the locking mechanism in this invention.

[0036] Figure 3 This is a schematic diagram of the grouting process of the present invention.

[0037] Figure 4 This is a schematic diagram of the grouting closed state of the present invention.

[0038] In the diagram: 1-grouting pipe; 2-pipe opening; 3-fixed pipe; 4-connecting plate; 5-inner cylinder; 503-first discharge port; 504-installation groove; 505-locking block; 506-clamping block; 507-clamping groove; 508-outer pipe body; 509-second discharge port. Detailed Implementation

[0039] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0040] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0041] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0042] like Figures 1-4As shown, the hydraulic fracturing borehole sealing device of the present invention includes a grouting pipe 1, a pipe opening 2, a fixed pipe 3, a connecting plate 4, an inner cylinder 5, and an outer pipe body 508. The lower end of the grouting pipe 1 and the pipe opening 2 are integrated, and the connection is ensured by welding or integral molding process. The pipe opening 2 extends into the inside of the fixed pipe 3 and further extends into the inside of the inner cylinder 5 for injecting mortar into the inner cylinder 5. The fixed pipe 3 is fixedly connected to the inner cylinder 5 by a trumpet-shaped connecting plate 4. The small end of the connecting plate 4 is fixed to the outer wall of the fixed pipe 3 by bolts or welding, and the large end is fixed to the inner wall of the inner cylinder 5 in a similar manner. The trumpet-shaped design enhances structural stability and facilitates mortar flow. The inner cylinder 5 is disposed inside the outer pipe body 508, and the two are rotated together by bearings (not separately indicated in the figure) to ensure that the inner cylinder 5 can rotate flexibly within the outer pipe body 508. At the same time, a locking mechanism is used to lock it to prevent accidental rotation.

[0043] like Figure 2 As shown, the locking mechanism includes a locking block 505, a locking block 506, and a locking groove 507. The top of the inner cylinder 5 has multiple circumferentially distributed arc-shaped mounting grooves 504, each with a locking groove 507 on one side. The locking block 505 is slidably disposed within the mounting groove 504, with one end engaging with the locking block 506, which is embedded in the locking groove 507. The other end engages with the inner wall of the outer tube 508, forming a stable locking structure. When it is necessary to rotate the inner cylinder 5, the operator can remove the locking block 506, separating the locking block 505 from the outer tube 508, thus allowing the inner cylinder 5 to rotate freely relative to the outer tube 508. The locking block 506 and the locking groove 507 employ a detachable locking design for easy and quick operation.

[0044] The inner cylinder 5 has a first discharge port 503 on its side wall, and the outer pipe 508 has a second discharge port 509 on its side wall. Both are arc-shaped openings of similar size to ensure uniform mortar flow. The first discharge port 503 and the second discharge port 509 are aligned or misaligned by the relative rotation of the inner cylinder 5 and the outer pipe 508. When aligned, the mortar can enter the formation fissures in the borehole through the second discharge port 509. When misaligned, the grouting outlet is closed to prevent mortar leakage.

[0045] The specific steps for using the hydraulic fracturing borehole sealing device in actual construction, as described in this embodiment, are as follows:

[0046] Assembly and initial adjustment: At the construction site, insert the grouting pipe 1 into the fixed pipe 3, ensuring that the pipe opening 2 is aligned with the inlet end of the inner cylinder 5. Adjust the relative position of the inner cylinder 5 and the outer pipe body 508 so that the first discharge port 503 is aligned with the second discharge port 509, and lock the inner cylinder 5 and the outer pipe body 508 with the locking mechanism (locking block 505, locking block 506 and locking groove 507) to prevent accidental rotation.

[0047] Device hoisting: The assembled device (including grouting pipe 1, fixing pipe 3, connecting plate 4, inner cylinder 5, and outer pipe body 508) is hoisted into the borehole to the predetermined depth using hoisting equipment. The trumpet-shaped connecting plate 4 ensures the stability of the device in the borehole and adapts to construction environments at different angles and depths.

[0048] Discharge port adjustment: such as Figure 3 As shown, after the device reaches the target depth, the construction personnel remove the locking block 506, separating the locking block 505 from the outer tube 508 and releasing the locking mechanism. Subsequently, the outer tube 508 is rotated manually or mechanically to adjust the position of the second discharge port 509, aligning it with the formation fissures within the borehole. Once the first discharge port 503 and the second discharge port 509 are aligned, the mortar can flow out smoothly.

[0049] Grouting operation: High-pressure mortar is injected through grouting pipe 1. The mortar enters the inner cylinder 5 through pipe opening 2 and is evenly filled into the formation fissures through aligned first outlet 503 and second outlet 509. During grouting, the top of the outer pipe 508 is fixed to prevent slippage and ensure the stability of the outlet position. The arc-shaped outlet design and size matching ensure uniform mortar distribution and improve the sealing effect.

[0050] Grouting completion and withdrawal: (e.g.) Figure 4 As shown, after grouting is completed, the construction personnel rotate the inner cylinder 5 again to misalign the first outlet 503 with the second outlet 509, closing the grouting outlet to prevent mortar backflow or leakage. After the mortar solidifies inside the borehole, the entire device is removed using hoisting equipment. The quick unlocking and rotation design of the locking mechanism simplifies the removal operation and reduces construction difficulty.

[0051] This device is particularly suitable for hydraulic fracturing and borehole sealing operations in coalbed methane and shale gas extraction, exhibiting excellent performance especially in complex geological conditions such as well-developed fractures, soft roofs, or large borehole inclination angles. In a shale gas extraction project, the borehole diameter was 100mm, the depth reached 1500m, and the formation was highly fractured. Using this device, the construction personnel were able to complete the alignment and locking of the discharge port within 5 minutes, the grouting process took approximately 20 minutes, the mortar filling rate reached over 95%, and there was no significant leakage after sealing, significantly better than the 80% filling rate of traditional devices. The device dimensions remained stable under high-pressure grouting (pressure up to 10MPa) without volume expansion, successfully adapting to narrow borehole environments. Compared to traditional devices, this invention reduces operation time by approximately 30%, lowers the risk of secondary construction, and demonstrates efficient and stable sealing performance.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A sealing device for hydraulic fracturing boreholes, characterized in that: It includes a grouting pipe, an inner cylinder, and an outer pipe body; the inner cylinder is disposed inside the outer pipe body, and the inner cylinder and the outer pipe body are rotatably engaged and locked by a locking mechanism; The inner cylinder has a fixed pipe at its inlet end; the lower end of the grouting pipe has an integral opening that extends into the inner cylinder and into the fixed pipe to inject mortar into the inner cylinder; the inner cylinder has a first outlet on its side wall and the outer pipe has a second outlet on its side wall; the first outlet and the second outlet are aligned or misaligned by rotation between the inner cylinder and the outer pipe, allowing the mortar to enter the borehole through the second outlet or to close the grouting outlet. The locking mechanism includes a locking block and a locking block. The top of the inner cylinder has multiple circumferentially distributed mounting grooves, and one side of the mounting groove has a locking slot. The locking block is located in the mounting groove, and one end of it engages with the locking block located in the locking slot. The locking block is embedded in the locking slot, and the other end engages with the inner wall of the outer tube. When the locking block is removed, the locking block separates from the outer tube, and the inner cylinder and the outer tube can rotate at this time. The mounting groove is arc-shaped. The locking block and the locking slot have a separable locking structure.

2. The hydraulic fracturing borehole sealing device according to claim 1, characterized in that: The fixed tube and the inner cylinder are connected by a connecting plate, which is trumpet-shaped, with the small end connected to the fixed tube and the large end connected to the inner wall of the inner cylinder.

3. The hydraulic fracturing borehole sealing device according to claim 1, characterized in that: The first discharge port and the second discharge port are the same or similar in size to ensure uniform mortar output.

4. A method of using a hydraulic fracturing borehole sealing device according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1. Adjust and install the inner cylinder and outer tube to align the first discharge port with the second discharge port, and lock the inner cylinder and outer tube. S2. Insert the grouting pipe into the fixed pipe, ensuring that the pipe opening is aligned with the inside of the inner cylinder; S3. The hydraulic fracturing borehole sealing device is hoisted into the borehole to the target depth. S4. Rotate the outer tube and adjust the second discharge port until it is aligned with the formation fracture. S5. Inject mortar through the grouting pipe, so that the mortar enters the fixed pipe and fills the formation fissures evenly through the first outlet and the second outlet. S6. After grouting is completed, release the locking block from the slot, rotate the inner cylinder to misalign the first and second discharge ports, and remove the device after the mortar has solidified.

5. The method of use according to claim 4, characterized in that: In step S6, the top of the outer tube is fixed to prevent it from sliding, while the inner cylinder is rotated to adjust the direction of the first discharge port, thereby stopping the grouting.

Images