A wellhead limited-entry guide annulus displacement system

Abstract

The application discloses a wellhead limited-distance guide annulus displacement system, which comprises a power source, a push rod cylinder, an elbow pipe and an intelligent pressure relief monitoring device connected in sequence along the direction from the ground to the casing annulus; the intelligent pressure relief monitoring device is connected with a wellhead cross; a guide joint assembly and a guide counterweight mechanism are connected in sequence from top to bottom in the casing annulus; a guide channel is arranged in the intelligent pressure relief monitoring device; a guide protection pipe is arranged in the guide channel; a flexible hose is arranged in the guide protection pipe; a compression spring is arranged in the elbow pipe; the guide protection pipe extends into the casing annulus; a gate valve in communication with the guide channel is further arranged; the push rod cylinder is vertically arranged; the intelligent pressure relief monitoring device is horizontally arranged; the push rod of the push rod cylinder is used for pushing the compression spring; and one end of the flexible hose in the guide protection pipe penetrates out of the guide protection pipe and enters the guide joint assembly under the action of the compression spring. The application realizes annular bidirectional sealing, pressure isolation and fluid displacement, and significantly improves operation safety, sealing reliability and construction efficiency.

Description

Technical Field

[0001] This invention relates to the field of wellbore operation technology in oil and gas field development, and in particular to a wellhead distance-limited guide annulus replacement system. Background Technology

[0002] During oil and gas extraction, uneven distribution of cement slurry during solidification and settling can lead to a lack of cement slurry or poor consolidation quality in the annulus between the technical casing and the production casing. This prevents the cement sheath from effectively sealing the space between the casing and the formation. Such poor annulus sealing can cause casing corrosion, perforation, or even breakage, severely impacting the well's service life. Furthermore, some wellbores may experience cross-channeling, allowing surface or formation gases and harmful substances to enter the casing annulus, resulting in increased annular pressure, environmental pollution, and potential safety hazards.

[0003] Existing methods for managing pressurized annulus in casing systems have significant limitations. One common method is to pull out the casing string, repair or replace the leaking area, and then run it back into the well to continue production. However, this method is not only costly in terms of manpower, resources, and time, but also technically challenging. Furthermore, it is prone to safety accidents such as blowouts, personnel injuries, and leaks of harmful gases during the casing string pulling and secondary well completion operations. Simultaneously, the suspension of operations significantly impacts the production progress and output of oil and gas fields. Another method is to inject cement into the annulus to seal microfractures. However, cement annulus fractures are usually small, and cement slurry containing solid particles is difficult to fully fill deep into the annulus, resulting in high construction difficulty, high risk, low success rate, and short effective period. In addition, while some methods can alleviate pressurized annulus problems, they require long-term monitoring and maintenance, which also consumes significant manpower and resources. For example, injecting annulus protective fluid into the annulus of pressurized gas wells from the surface requires regular monitoring of the protective fluid's condition and periodic replenishment, replacement, and performance adjustment, leading to high operation and maintenance costs.

[0004] In offshore oilfield platform operations, annular injection operations face increasingly complex challenges. Due to limited platform space and the close proximity of individual wellheads to adjacent wellheads, conventional annular injection, plugging, or cement injection operations are easily affected by space constraints, resulting in high construction difficulty, high operational safety risks, and potential interference with the normal production operations of adjacent wellheads. Traditional methods, such as removing casing strings for repair or injecting cement into micro-fractures in the annulus, require significant manpower, resources, and time in confined spaces, and are prone to safety accidents such as blowouts, personnel injuries, and hazardous gas leaks. Even with periodic injection of annular protective fluid, frequent monitoring and maintenance are necessary, and the high frequency of operations on space-constrained offshore platforms further increases operational complexity and safety risks. Therefore, the application of existing annular pressurization treatment technologies in the offshore oilfield environment is significantly limited, making it difficult to meet the demands for safe, efficient, and continuous production.

[0005] Whether it is an onshore or offshore oil and gas field, the annular pressure treatment process or the annular protective fluid replacement process must ensure the safety and sealing of the annular pressure release process, as well as the bidirectional sealing of the annular during operation. Once natural gas leaks, it will cause great safety hazards and property losses to oil and gas wells, platforms and workers. Therefore, bidirectional sealing of the annular is the key to safety management during operation. Summary of the Invention

[0006] The purpose of this application is to provide a wellhead limited-distance directional annulus replacement system to solve the problems mentioned in the background art.

[0007] The present invention solves its problems through the following technical solution: A wellhead-limited guide annulus replacement system includes a power source, a push rod cylinder, a bend, and an intelligent pressure relief monitoring device connected sequentially along the ground towards the casing annulus. The intelligent pressure relief monitoring device is connected to the wellhead four-way connector. A guide joint assembly and a guide counterweight mechanism are connected sequentially from top to bottom within the casing annulus. The intelligent pressure relief monitoring device has a guide channel, within which a guide sleeve is installed. A flexible hose is installed within the guide sleeve, and a compression spring is installed within the bend. The guide sleeve extends into the casing annulus. The intelligent pressure relief monitoring device has a gate valve connected to the guide channel and a storage tank. The push rod cylinder is vertically positioned, and the intelligent pressure relief monitoring device is horizontally positioned. The power source is used to move the push rod of the push rod cylinder. The push rod of the push rod cylinder pushes the front end of the compression spring into the guide sleeve. Under the action of the compression spring, one end of the flexible hose inside the guide sleeve passes through the guide sleeve and enters the guide joint assembly.

[0008] Optionally, the guide channel further includes a roller sleeve and a roller, wherein the roller sleeve is disposed within the guide tube near one end of the guide joint assembly via the roller, and the roller sleeve rolls relative to the roller.

[0009] Optionally, the guide joint assembly includes a pressure sleeve, a pressure inner joint, a spring, and a guide head, which are arranged sequentially from top to bottom via a wire rope.

[0010] Optionally, the guide counterweight mechanism includes a connecting cap, multiple spherical counterweight units, and a counterweight guide head arranged sequentially from top to bottom via a wire rope. The uppermost spherical counterweight unit and the lowermost spherical counterweight unit are respectively provided with fixing caps, and a support spring is provided between adjacent spherical counterweight units.

[0011] Optionally, one end of the push rod cylinder is connected to the power source, and the other end is connected to the flange at the liquid inlet direction of the bend; one end of the intelligent pressure relief monitoring device is connected to the flange at the liquid outlet direction of the bend, and the other end is connected to the flange at the wellhead four-way; the guide channel, the guide joint assembly, and the guide counterweight mechanism are connected by a steel wire rope.

[0012] Optionally, the intelligent pressure relief monitoring device further includes a pressure sensor and a temperature sensor, which are connected to the guide channel.

[0013] Optionally, the intelligent pressure relief monitoring device further includes a flow meter and a flexible hose tension monitor, wherein the flow meter is connected to the guide channel and the flexible hose tension monitor is located inside the guide channel.

[0014] Optionally, the storage tank is equipped with a gas discharge pipe, a liquid discharge pipe, and a discharge valve.

[0015] Optionally, the flexible hose is a high-pressure flexible composite tube or a steel wire spiral hose.

[0016] In summary, the technical effects and advantages of this invention are as follows: 1. This invention involves installing a bend at the wellhead and connecting the entire system via a flexible hose, creating a leak-free, fully sealed channel composed of the bend, an intelligent pressure relief monitoring device, a gate valve, and a guide channel. This design not only solves the problem of limited space at the wellhead wing valve location, preventing the parallel arrangement of thrust and guide delivery power components, but also effectively seals the casing annulus, isolating it from wellbore pressure and achieving both a fully sealed channel and optimized wellhead space. 2. Roller sleeves and rollers are installed within the guide channel to guide the flexible hose to achieve a 90° reversal. With the coordinated action of the guide joint assembly and the guide counterweight mechanism, the flexible hose maintains a stable shape and direction of movement during its smooth descent, achieving precise guidance and trajectory control. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the wellhead spacing guide annulus replacement system in one embodiment of the present invention; Figure 2 This is a cross-sectional view of a wellhead distance-limiting guide annulus replacement system in one embodiment of the present invention, with the bend pipe, push rod cylinder and power source removed; Figure 3 This is a schematic diagram of the guide channel structure in one embodiment of the present invention; Figure 4 This is a schematic diagram of the guide joint assembly in one embodiment of the present invention; Figure 5This is a schematic diagram of the guiding counterweight mechanism in one embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of the roller and roller sleeve in one embodiment of the present invention; Figure 7 This is a schematic diagram of the connection between the push rod cylinder and the bent pipe in one embodiment of the present invention.

[0019] in: 1. Push rod cylinder; 2. Bend; 3. Intelligent pressure relief monitoring device; 4. Gate valve; 5. Flexible hose; 6. Guide channel; 601. Compression spring; 602. Guide sleeve; 603. Roller sleeve; 604. Roller; 7. Guide joint assembly; 701. Pressure sleeve; 702. Pressure inner joint; 703. Spring; 704. Wire rope; 705. Guide head; 8. Guide counterweight mechanism; 801. Connecting cap; 802. Fixing cap; 803. Support spring; 804. Spherical counterweight unit; 805. Counterweight guide head; 9. Wellhead four-way valve; 10. Wellbore; 1001. Technical casing; 1002. Production casing; 1003. Annulus; 11. Power source; 12. Storage tank; 13. Push rod. Detailed Implementation

[0020] The technical solutions of 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] The problem this invention aims to solve is that existing casing annulus pressurization treatment technologies suffer from high costs, high risks, low efficiency, and poor results, failing to meet the needs of long-term, efficient, and safe development of oil and gas fields. Furthermore, considering the limited space on offshore oilfield platforms and the close proximity of individual wellheads to other wellheads, this invention provides a system with guiding capabilities that enables bidirectional sealing of the annulus and replacement of protective fluid within a limited space. The goal is to improve the safety, construction efficiency, and reliability of casing annulus pressurization treatment.

[0022] This embodiment proposes a wellhead-limited guide annulus replacement system, such as... Figures 1-7As shown, the system includes a power source 11, a push rod cylinder 1, a bend 2, and an intelligent pressure relief monitoring device 3 connected sequentially along the ground towards the casing annulus 1003 (in the fluid inlet direction). The intelligent pressure relief monitoring device 3 is connected to the wellhead four-way connector 9. A guide joint assembly 7 and a guide counterweight mechanism 8 are connected sequentially from top to bottom within the casing annulus 1003. The intelligent pressure relief monitoring device 3 has a guide channel 6, within which a guide protective tube 602 is installed. A flexible hose 5 is installed within the guide protective tube 602, and a compression spring 601 is installed within the bend 2. The guide protective tube 602 extends into… In the annulus 1003, the intelligent pressure relief monitoring device 3 is equipped with a gate valve 4 that communicates with the guide channel 6. The gate valve 4 is connected to the storage tank 12. The push rod cylinder 1 is vertically arranged, and the intelligent pressure relief monitoring device 3 is horizontally arranged. The power source 11 is used to push the push rod 13 of the push rod cylinder 1 to move. The push rod 13 of the push rod cylinder 1 is used to push the front end of the compression spring 601 into the guide tube 602. Under the action of the compression spring 601, one end of the flexible hose 5 in the guide tube 602 passes through the guide tube 602 and enters the guide joint assembly 7.

[0023] The compression spring 601 is located inside the bend 2. The push rod 13 of the push rod cylinder 1 is connected to one end of the spring 703, and the other end of the spring 703 extends into the guide tube 602. The spring 703 is always compressed and bent at 90°, cleverly converting the vertical movement of the push rod 13 into the horizontal movement of the flexible hose 5. Therefore, the push rod 13 moves vertically, which is converted into the horizontal movement of the flexible hose 5 by the compression and bending of the compression spring 601 inside the bend 2. The compression and recovery process of the compression spring 601 in the guide channel 6 can drive the flexible hose 5 to move along the guide tube 602. The guide tube 602 can constrain, guide, and protect the flexible hose 5, so that it maintains a stable shape and direction during movement. There is a gap between the guide tube 602 and the guide channel 6 for the gas and liquid to flow in the annulus 1003. The gas and liquid in the annulus 1003 enter the storage tank 12 through the gate valve 4. The bend 2, intelligent pressure relief monitoring device 3, gate valve 4 and guide channel 6 are all connected to the pressure of the annulus 1003, so they need to be sealed. The sealing is achieved by setting a sealing element, and the sealing method is existing technology.

[0024] Optionally, the guide channel 6 further includes a roller sleeve 603 and a roller 604. The roller sleeve 603 and the roller 604 are both disposed inside the guide tube 602 near one end of the guide joint assembly 7, and the roller sleeve 603 rolls relative to the roller 604. The roller sleeve 603 and the roller 604 of the guide channel 6 guide the flexible hose 5 to change direction by 90°. In this embodiment, the roller sleeve 603 is installed 10 mm away from the end of the guide tube 602, and both ends of the roller 604 are installed in the threaded holes of the guide tube 602. The roller sleeve 603 is installed on the roller 604, and the roller sleeve 603 is mounted on the roller 604. Due to the gap between the roller sleeve 603 and the roller 604, they are in a rotating state.

[0025] Specifically, the guide connector assembly 7 includes, from top to bottom, a crimp sleeve 701, a crimp inner connector 702, a spring 703, and a guide head 705, which are sequentially connected by a wire rope 704. The crimp sleeve 701 is used to fix the crimp inner connector 702. The crimp inner connector 702 is installed at the end of the flexible hose 5, thereby connecting the spring 703, the wire rope 704, and the guide head. The function of the spring 703 is to constrain the guide head 705. When the guide head 705 encounters an obstruction, the spring 703 compresses, allowing the guide head 705 to receive additional force, deflecting the obstructed position and thus avoiding the obstructed area.

[0026] Specifically, the guide counterweight mechanism 8 includes, from top to bottom, a connecting cap 801, multiple spherical counterweight units 804, and a counterweight guide head 805, all connected by a steel wire rope 704. The uppermost spherical counterweight unit 804 and the lowermost spherical counterweight unit 804 are respectively provided with fixing caps 802, and supporting springs 803 are provided between adjacent spherical counterweight units 804. The guide counterweight mechanism 8 and the guide joint assembly 7 are connected by the intermediate steel wire rope 704. The connecting cap 801 serves two purposes: first, to fix the steel wire rope 704, and second, to connect with the guide head 705.

[0027] Optionally, one end of the push rod cylinder 1 is connected to the power source 11, and the other end is connected to the flange at the liquid inlet direction of the bend 2; one end of the intelligent pressure relief monitoring device 3 is connected to the flange at the liquid outlet direction of the bend 2, and the other end is connected to the flange at the wellhead four-way 9; the guide channel 6, the guide joint assembly 7, and the guide counterweight mechanism 8 are connected by a steel wire rope 704.

[0028] Optionally, the intelligent pressure relief monitoring device 3 further includes a pressure sensor and a temperature sensor (or a pressure gauge, thermometer), which are connected to the guide channel 6. In this embodiment, connection holes for the pressure sensor and temperature sensor are provided on the flange, and the pressure sensor and temperature sensor are connected to the guide channel 6. The setting and installation of the pressure sensor and temperature sensor are existing technologies.

[0029] Optionally, the intelligent pressure relief monitoring device 3 further includes a flow meter and a flexible hose tension monitor. The flow meter is connected to the guide channel 6, and the flexible hose tension monitor is located within the guide channel 6. The installation of the flow meter and the flexible hose tension monitor is prior art.

[0030] Optionally, the storage tank 12 is provided with a gas discharge pipe, a liquid discharge pipe, and a discharge valve.

[0031] Optionally, the flexible hose 5 is a high-pressure flexible composite tube or a steel wire spiral hose; it has high temperature and high pressure resistance, corrosion resistance and torsion resistance.

[0032] In this embodiment, the operation process employs a pressure-temperature-flow-tension coupling monitoring method, an annular bidirectional sealing method, and a wellhead distance-limiting guidance design method.

[0033] The working process of this embodiment: Before operation, connect each unit device of the system in this embodiment in sequence; before formally carrying out injection or replacement operation, first test the intelligent pressure relief monitoring device 3. After confirming that the connection of the bend 2, intelligent pressure relief monitoring device 3, gate valve 4 and guide channel 6 is firm and leak-free by using the pressure sensor, temperature sensor (or pressure gauge, thermometer), flow meter and flexible pipe tension monitoring system, open the gate valve 4 to the target pressure, so that the gas in the wellbore enters the storage tank 12 through the channel, and perform component analysis and harmless treatment on the gas in the storage tank 12.

[0034] After the pressure test is passed, the power source 11 is started to drive the push rod cylinder 1. The push rod cylinder 1 pushes the compression spring 601 inside the bend 2 into the guide tube 602 and compresses it, thereby compressing the spring 601 and driving the flexible hose 5 forward along the guide tube 602. Under the constraint and protection of the guide tube 602, the flexible hose 5 maintains a stable shape; when it moves to the position of the roller sleeve 603 and the roller 604, under the synergistic action of the guide joint assembly 7 and the guide counterweight mechanism 8, it achieves a 90° reversal and smoothly enters the wellbore annulus 1003, descending along the predetermined trajectory to the predetermined position. This process effectively prevents the flexible tube from twisting, tangling and deforming, achieving precise guidance and distance control.

[0035] After the flexible hose 5 is lowered, annular injection or replacement operations can be formally performed. After the operation, the system can be recovered as a whole using a dedicated recovery device for easy reuse, improving operational efficiency and safety. Annular injection or replacement operations are existing technologies; annular injection involves injecting a plugging agent or annular protective fluid into the annulus. Existing technology involves direct injection through the wellhead's wing valve. This application uses a lowered flexible hose for injection. Replacement operations replace the existing protective fluid in the annulus. Existing technology involves direct injection through the wellhead's wing valve, utilizing gravity for replacement. This application uses a lowered flexible hose for injection.

[0036] This embodiment of a wellhead-limited guide annulus replacement system includes a power source, push rod cylinder, bend pipe, intelligent pressure relief monitoring device, gate valve, high-pressure flexible pipe, guide channel, guide joint assembly, guide counterweight mechanism, and storage tank. The system forms a leak-free, fully sealed channel. A 90° reversal of the high-pressure flexible pipe is achieved using a roller sleeve and rollers. The guide joint assembly and guide counterweight mechanism work together to ensure stable and accurate positioning during the lowering process. The intelligent pressure relief monitoring device has pressure, temperature, flow rate, and tension monitoring functions, enabling real-time monitoring and safe pressure relief. The system has a compact structure and is suitable for offshore platforms and onshore well sites with limited wellhead space. It can efficiently carry out annulus injection or fluid replacement operations, avoiding the high risks and costs of traditional pipe pulling or cement injection. This invention achieves bidirectional annulus sealing, pressure isolation, and fluid replacement, significantly improving operational safety, sealing reliability, and construction efficiency.

[0037] Finally, it should be noted that: the accompanying drawings of the embodiments disclosed in this invention only involve structures related to the embodiments disclosed in this invention, and other structures can refer to general designs. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other.

[0038] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A wellhead distance-limiting guide annulus replacement system, characterized in that, The system includes a power source, a push rod cylinder, a bend, and an intelligent pressure relief monitoring device, connected sequentially along the ground towards the casing annulus. The intelligent pressure relief monitoring device is connected to the wellhead four-way connector. A guide joint assembly and a guide counterweight mechanism are connected sequentially from top to bottom within the casing annulus. The intelligent pressure relief monitoring device has a guide channel, within which a guide sleeve is installed. A flexible hose is installed within the guide sleeve, and a compression spring is installed within the bend. The guide sleeve extends into the casing annulus. The intelligent pressure relief monitoring device has a gate valve connected to the guide channel and a storage tank. The push rod cylinder is vertically positioned, and the intelligent pressure relief monitoring device is horizontally positioned. The power source is used to move the push rod of the push rod cylinder. The push rod of the push rod cylinder pushes the front end of the compression spring into the guide sleeve. Under the action of the compression spring, one end of the flexible hose inside the guide sleeve passes through the guide sleeve and enters the guide joint assembly.

2. The wellhead spacing guide annulus replacement system according to claim 1, characterized in that, The guide channel also includes a roller sleeve and a roller. The roller sleeve is located inside the guide tube near one end of the guide joint assembly via the roller. The roller sleeve rolls relative to the roller.

3. The wellhead spacing guide annulus replacement system according to claim 1, characterized in that, The guide joint assembly includes, from top to bottom, a pressure sleeve, a pressure inner joint, a spring, and a guide head, which are arranged sequentially by a wire rope.

4. The wellhead spacing guide annulus replacement system according to claim 3, characterized in that, The guiding counterweight mechanism includes a connecting cap, multiple spherical counterweight units, and a counterweight guide head arranged sequentially from top to bottom via a steel wire rope. The uppermost spherical counterweight unit and the lowermost spherical counterweight unit are respectively provided with fixing caps, and a support spring is provided between adjacent spherical counterweight units.

5. The wellhead spacing guide annulus replacement system according to claim 1, characterized in that, One end of the push rod cylinder is connected to the power source, and the other end is connected to the flange at the liquid inlet direction of the bend; one end of the intelligent pressure relief monitoring device is connected to the flange at the liquid outlet direction of the bend, and the other end is connected to the flange at the wellhead four-way; the guide channel, the guide joint assembly, and the guide counterweight mechanism are connected by a steel wire rope.

6. The wellhead spacing guide annulus replacement system according to claim 1, characterized in that, The intelligent pressure relief monitoring device also includes a pressure sensor and a temperature sensor, which are connected to the guide channel.

7. The wellhead spacing guide annulus replacement system according to claim 1, characterized in that, The intelligent pressure relief monitoring device also includes a flow meter and a flexible hose tension monitor. The flow meter is connected to the guide channel, and the flexible hose tension monitor is located inside the guide channel.

8. The wellhead spacing guide annulus replacement system according to claim 1, characterized in that, The storage tank is equipped with a gas discharge pipe, a liquid discharge pipe, and a discharge valve.

9. The wellhead spacing guide annulus replacement system according to claim 1, characterized in that, The flexible hose is either a high-pressure flexible composite tube or a steel wire wound hose.

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