A full-gauge switchable frac completion device and method of completion

Abstract

The present application relates to a kind of petroleum development technical field, in particular to a kind of full bore switchable fracturing completion device and completion method.Full bore switchable fracturing completion device is connected with more than one level of unblocking fracturing packer at the lower end of Y445 release packer, and full bore unlimited level fracturing switch, hydraulic oil production switch and constant pressure one-way balance valve are installed between two unblocking fracturing packers respectively, ground wellhead fracturing supercharging device is installed at ground wellhead, full bore unlimited level fracturing switch is used to realize full bore fracturing, ground wellhead fracturing supercharging device is used to improve the pressure of fracturing fluid, hydraulic oil production switch is used to realize separate layer oil production, and constant pressure one-way balance valve is used to realize pressure relief after fracturing.The beneficial effect is that the present application combines full bore unlimited level fracturing switch with hydraulic oil production switch for separate layer oil production, without the need to pull out fracturing string and then lower oil production equipment, without the need for multiple construction, and without the need for superhigh pressure fracturing equipment, thereby reducing operation cost.

Description

Technical Field

[0001] This invention relates to the field of petroleum development technology, and in particular to a full-bore switchable fracturing completion device and completion method. Background Technology

[0002] In the petroleum industry, well completion technology is a crucial link between drilling and oil production. Its core objective is to establish an efficient and stable connection between the oil and gas reservoir and the wellbore, while protecting the reservoir, in order to achieve high and stable production and extend well life. Conventional well completion techniques include perforated completion, open-hole completion, slotted liner completion, and gravel packing completion. However, with the development of petroleum development technology, a large amount of oil reservoirs are still stored in hard rock. To obtain this oil hidden in the rock, fracturing operations are required. Fracturing involves using strong external pressure to crush the rock, releasing the hidden oil and gas. To improve the effectiveness of fracturing operations, layered fracturing has been adopted. This method allows for the full utilization of limited fracturing fluid, maximizing its effectiveness. Currently, the fracturing switches used in layered fracturing typically employ a step-by-step ball-dropping method. However, due to the limited inner diameter of the fracturing tubing, the decreasing inner diameter at each stage directly affects the flow of fracturing fluid, impacting the fracturing effect and consequently affecting the overall oil and gas resource development of the well, as well as the implementation of well completion procedures. Furthermore, existing fracturing operations require retrieving the entire fracturing tubing after fracturing and then re-installing the production tubing. This not only necessitates repeated operations, increasing costs and wasting time, but also introduces significant risks due to varying well conditions, such as the possibility of blowouts in some fracturing wells. Furthermore, the rocks in deep strata have high compressive strength, requiring pressures exceeding 100 MPa to fracture. This necessitates extremely powerful fracturing trucks for existing fracturing operations, sometimes even requiring ultra-high pressure fracturing equipment. These equipment are expensive and difficult to manufacture, resulting in high costs and safety hazards associated with fracturing operations. Summary of the Invention

[0003] The purpose of this invention is to address the aforementioned deficiencies in existing technologies by providing a full-bore switchable fracturing and completion device and method. This device combines a full-bore, infinite-stage fracturing switch with a hydraulic production switch for stratified oil production. It eliminates the need to retrieve the fracturing tubing and run it back into the production equipment, enabling fracturing and oil production to be performed in a single operation, reducing the need for multiple operations and lowering operating costs. Furthermore, by utilizing a newly designed surface wellhead fracturing booster device, it eliminates the need for ultra-high-pressure fracturing equipment, significantly reducing fracturing costs and safety hazards.

[0004] The present invention discloses a full-bore switchable fracturing and completion device, the technical solution of which includes a blind plug, a hydraulic production switch, a Y445 release packer, tubing, and wellhead equipment. It further includes a constant-pressure one-way balance valve, a full-bore unlimited-stage fracturing switch, a releaseable fracturing packer, and a surface wellhead fracturing booster device. The Y445 release packer is connected via tubing. At the lower end of the Y445 release packer, one or more releaseable fracturing packers are connected to isolate different reservoirs. A blind plug is installed at the bottom. Between two releaseable fracturing packers, the full-bore unlimited-stage fracturing switch, the hydraulic production switch, and the constant-pressure one-way balance valve are connected via tubing. A surface wellhead fracturing booster device is installed at the wellhead. Full-bore fracturing is achieved through the full-bore unlimited-stage fracturing switch. The surface wellhead fracturing booster device increases the pressure of the fracturing fluid. Layered oil production is achieved through the hydraulic production switch. Pressure relief after fracturing is achieved through the constant-pressure one-way balance valve. The surface wellhead fracturing booster device includes a hydraulic booster pump, a three-position four-way solenoid valve, a booster pipeline control valve, a pressure relief control valve, a pressure relief pipeline pressure gauge, a fracturing fluid main pipeline, a fracturing fluid main pipeline control valve, a fracturing pump truck, a fracturing fluid storage tank, a supply pipeline, and a return pipeline. The upper part of the hydraulic booster pump is connected to the fracturing pump truck through the three-position four-way solenoid valve, the booster pipeline control valve, and the supply pipeline. It is connected to the fracturing fluid storage tank through the return pipeline. The middle part of the supply pipeline is connected to the middle part of the hydraulic booster pump through the fracturing fluid main pipeline and the fracturing fluid main pipeline control valve. The lower middle side of the hydraulic booster pump is equipped with a pressure relief control valve and a pressure relief pipeline pressure gauge. The full-bore unlimited-stage fracturing switch includes a fracturing switch device, a fracturing switch tracker, a circulating fluid controller, a fracturing fluid pressure relief device, a cylinder liner body, and a central tube. The cylinder liner body is installed outside the central tube. The fracturing fluid pressure relief device is installed on the top of the cylinder liner body. The fracturing switch device is installed below the fracturing fluid pressure relief device. The fracturing switch tracker is installed below the fracturing switch device. The circulating fluid controller is installed at the bottom of the fracturing switch tracker.

[0005] Preferably, the aforementioned hydraulic booster pump includes a booster inlet, a return inlet, a fracturing fluid inlet, a pressure relief port, a hydraulic cylinder body, a return spring, a fracturing fluid check valve, a booster cylinder, and a booster piston. The lower end of the booster cylinder is connected to the hydraulic cylinder body, and the lower end of the hydraulic cylinder body is fixedly connected to the wellhead flange. The sidewalls of the booster cylinder are respectively provided with a booster inlet and a return inlet. A booster piston is installed in the inner cavity of the booster cylinder, and the upper surface area of ​​the booster piston is larger than the lower surface area. The upper side of the outer wall of the hydraulic cylinder body is provided with a fracturing fluid inlet, and the lower side is provided with a pressure relief port. A fracturing fluid check valve is installed in the inner cavity of the hydraulic cylinder body, and a return spring is installed on the lower side of the fracturing fluid check valve.

[0006] Preferably, the upper part of the central tube of the above-mentioned full-bore unlimited-stage fracturing switch is provided with a fracturing fluid internal drain hole, and the upper side of the cylinder liner body is provided with a fracturing fluid external drain hole. A sliding sleeve is installed on the inner side of the fracturing fluid external drain hole. A fracturing switch is installed between the fracturing fluid internal drain hole and the sliding sleeve. The middle outer wall of the central tube is provided with a shallow track groove, the lower part of the central tube is provided with a circulation fluid port, and the bottom end is provided with a central tube lower connector.

[0007] Preferably, the fracturing switch includes an opening piston and a constant pressure opening valve. The opening piston is located in the annulus between the cylinder liner body and the central tube. A liquid passage is provided at the center of the opening piston, and a constant pressure opening valve is installed on the liquid passage. The upper surface area of ​​the opening piston is larger than the lower surface area.

[0008] Preferably, the fracturing switch track device mentioned above includes a rotating cap, a rotating ring, a track pin, and a rotating cap spring. The upper end of the rotating cap contacts the lower end of the sliding sleeve and the constant pressure opening valve. The rotating cap spring is installed at the lower end of the rotating cap. The rotating ring is installed inside the rotating cap. The track pin is installed on the rotating ring. The track pin is connected to a shallow track groove provided on the outer wall of the central tube.

[0009] Preferably, the above-mentioned circulating fluid controller includes a controller body, a balance plug, and a balance spring. The upper end of the controller body is a necked-up connector, which is threadedly connected to the lower end of the cylinder liner body. A balance plug is installed in the annulus between the necked-up connector and the central tube of the controller body. A balance spring is installed at the lower end of the balance plug. The outer diameter of the balance plug is the same as the inner diameter of the necked-up connector, and the inner diameter of the controller body is larger than the inner diameter of the necked-up connector. When the balance plug moves down into the lower part of the controller body, the circulating fluid communicates with the circulating fluid port along the annulus between the controller body and the central tube.

[0010] Preferably, the fracturing fluid pressure relief device includes a pressure relief device body, an upper pressure relief channel, a pressure relief valve, and a lower pressure relief hole. The pressure relief device body is installed on the top of the cylinder liner body and the central tube. The inner wall of the pressure relief device body is threaded to the top of the central tube, and the outer wall of the pressure relief device body is threaded to the top of the cylinder liner body. The pressure relief device body is provided with an upper pressure relief channel, and a pressure relief valve is installed in the upper pressure relief channel. The bottom of the pressure relief valve is provided with a lower pressure relief hole, which communicates with the annulus of the cylinder liner body and the central tube.

[0011] Preferably, the aforementioned constant pressure one-way balancing valve includes a balancing valve body, a main pressure relief channel, a constant pressure plug, a constant pressure spring, an adjusting screw, and an internal pressure relief hole. The main pressure relief channel is provided inside the outer wall of the balancing valve body, and the outer end of the main pressure relief channel is connected to the outer wall surface of the balancing valve body. A pressure relief valve seat is provided inside the main pressure relief channel, and a constant pressure plug is installed under the pressure relief valve seat. A constant pressure spring is installed at the lower part of the constant pressure plug, and an adjusting screw is installed at the lower end of the constant pressure spring. An internal pressure relief hole is provided in the middle of the inner wall of the balancing valve body, and one end of the internal pressure relief hole is connected to the inner wall surface of the balancing valve body, and the other end is connected to the lower part of the constant pressure plug in the main pressure relief channel.

[0012] Preferably, the aforementioned resealable fracturing packer includes an upper packer connector, a central packer tube, an expanding rubber tube, a lower rubber tube support sleeve, a release mechanism, a setting inlet, a rubber tube skeleton, and a lower packer connector. The upper part of the central packer tube is provided with a setting inlet. The upper end of the central packer tube is connected to the upper packer connector, and the lower end is provided with the lower packer connector. The lower rubber tube support sleeve is installed above the lower packer connector. An expanding rubber tube is installed between the upper packer connector and the lower rubber tube support sleeve, and a release mechanism is installed between the lower end of the expanding rubber tube and the lower rubber tube support sleeve. The interior of the expanding rubber tube is provided with a rubber tube skeleton. The release mechanism includes a fixing ring, a shear pin, and a locking ring. The lower end of the expanding rubber tube is connected to the fixing ring, and the fixing ring and the locking ring are connected by a shear pin.

[0013] The well completion method of the full-bore switchable fracturing completion device mentioned in this invention includes the following process: I. Assemble the full-bore switchable fracturing completion device: Install the surface wellhead fracturing booster at the surface wellhead, and run the Y445 drop-off packer through tubing. Connect three releaseable fracturing packers to the lower end of the Y445 drop-off packer to isolate the three reservoirs. Install a blind plug at the bottom. Connect the full-bore unlimited-stage fracturing switch, hydraulic production switch, and constant pressure one-way balance valve through tubing between the two releaseable fracturing packers. The fracturing switch rail of the first-stage full-bore unlimited-stage fracturing switch is in the long rail, so that the fracturing switch is in the downward one-way open state. The fracturing switch rails of the second and third-stage full-bore unlimited-stage fracturing switches are in the short rail, so that the fracturing switch is in the closed state. 2. Pressurized fluid is injected into the tubing through the surface wellhead fracturing booster device. The pressurized fluid enters the Y445 release packer along the tubing to achieve setting. Then, the fluid continues to flow downwards, setting one or more releaseable fracturing packers. 3. The fracturing operation begins sequentially on the three reservoirs: The fracturing pump truck in the surface wellhead fracturing booster unit continues to pressurize the fluid. The fracturing fluid in the storage tank flows along the supply line. Part of the fracturing fluid enters the booster inlet of the hydraulic booster pump via a three-position four-way solenoid valve, pushing the booster piston downwards. The return fluid under the booster piston flows back to the fracturing fluid storage tank via the return port, the three-position four-way solenoid valve, and the return line. The other part of the fracturing fluid enters the fracturing fluid inlet along the main fracturing fluid line, where it is further pressurized by the booster piston above. The pressurized fracturing fluid then pushes open the fracturing fluid check valve and enters the tubing. From there, it travels along the tubing to the first-stage full-bore unlimited-stage fracturing switch, and finally enters the first reservoir via the activated fracturing switch. To achieve continuous fracturing and maintain a stable fracturing fluid pressure at the fracturing fluid inlet, the pressure gauge in the relief pipeline continuously rises until it exhibits significant fluctuations, indicating that the rock in the first reservoir has been crushed. Once the pressure gauge drops to a stable value, the fracturing of the first reservoir is complete. After diffusion is complete, the relief port is opened to release the fracturing fluid from the tubing. The main relief channel in the constant pressure one-way balance valve opens, and the fluid in the first reservoir is depressurized along the main relief channel and the internal relief hole. Additionally, the fracturing switch tracker in the first-stage full-bore unlimited-stage fracturing switch moves to the short track, closing the fracturing switch and depressurizing the fracturing fluid relief device. Finally, the depressurization of the first reservoir is complete. The fracturing fluid is then pressurized using the surface wellhead fracturing booster device. This positions the fracturing switch tracker of the full-bore unlimited-stage fracturing switch for the second reservoir at the long track, thus opening the fracturing switch. Meanwhile, the fracturing switch trackers of the full-bore unlimited-stage fracturing switches for the first and third reservoirs are positioned at the short track, closing both fracturing switches. Fracturing is then performed on the second reservoir, followed by depressurization. The same process is repeated for the third reservoir, with depressurization performed after each fracturing operation. 4. After fracturing the three reservoirs separately, the Y445 release packer is released by pressurization, and the upper tubing string is pulled to the surface. The surface wellhead fracturing booster device is removed, and the production equipment is installed. Then, the pumping unit is run through tubing to carry out stratified oil production. When oil production is needed for the first reservoir, the casing is pressurized through the wellhead equipment. The hydraulic production switch for the first reservoir is in a one-way upward state, while the hydraulic production switches for the second and third reservoirs are in a closed state. At this time, the pumping unit operates to produce oil for the first reservoir. When oil production is needed for the second reservoir, the casing is pressurized through the wellhead equipment. The hydraulic production switch for the second reservoir is in a one-way upward state, while the hydraulic production switches for the first and third reservoirs are in a closed state. At this time, the pumping unit operates to produce oil for the second reservoir. Oil production is then carried out sequentially for the third reservoir, thus achieving stratified production of the three reservoirs downhole.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention combines a full-bore, unlimited-stage fracturing switch with a hydraulic production switch for stratified oil production. It eliminates the need to retrieve the fracturing tubing and re-install it in the production equipment, enabling fracturing and oil production in a single operation, reducing the need for multiple operations and lowering operating costs. The full-bore, unlimited-stage fracturing switch allows for stratified injection of fracturing fluid without reducing the flow rate in the central tubing, achieving full-bore injection of fracturing fluid. Furthermore, the switch can be hydraulically opened or closed, facilitating stratified fracturing of multiple reservoirs. Additionally, by simultaneously installing hydraulic production switches in each reservoir, stratified oil production can be achieved without retrieving the fracturing tubing and re-installing it separately. Moreover, this invention utilizes a newly designed surface wellhead fracturing booster device. By driving the booster piston in the booster cylinder to reciprocate downwards, the fracturing fluid entering the hydraulic cylinder body is pressurized, eliminating the need for expensive ultra-high-pressure fracturing equipment, significantly reducing fracturing costs and safety hazards. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure during the layered fracturing process of the present invention; Figure 2 This is a schematic diagram of a surface wellhead fracturing booster device; Figure 3 This is a schematic diagram of the structure of a hydraulic booster pump; Figure 4 This is a schematic diagram of the structure of a full-bore, unlimited-stage fracturing switch; Figure 5 This is a further structural schematic diagram of a full-bore, unlimited-stage fracturing switch; Figure 6 This is a schematic diagram of the state when the full-bore unlimited-stage fracturing switch is turned on; Figure 7 This is a schematic diagram of the shallow track groove structure; Figure 8 This is a schematic diagram of a constant pressure one-way balance valve; Figure 9 This is a schematic diagram of a constant pressure check valve during pressure relief. Figure 10 This is a schematic diagram of the structure of the unsealed fracturing packer of the present invention; Figure 11 This is a schematic diagram of the structure during the layered oil recovery process of the present invention; In the diagram: 1. Artificial well bottom; 2. Casing; 3. Blind plug; 4. Constant pressure one-way balance valve; 5. Full-bore unlimited-stage fracturing switch; 6. Hydraulic oil production switch; 7. Desealable fracturing packer; 8. Y445 drop-out packer; 9. Tubing; 10. Wellhead equipment; 11. Surface wellhead fracturing booster device; 12. Oil pump. Balance valve body 4.1, main pressure relief channel 4.2, constant pressure plug 4.3, constant pressure spring 4.4, pressure adjusting screw 4.5, internal pressure relief hole 4.6, upper connector internal thread 4.7, lower connector internal thread 4.8; 5.1 Fracturing switch, 5.2 Fracturing switch tracker, 5.3 Circulating fluid controller, 5.4 Fracturing fluid pressure relief device, 5.5 Cylinder liner body, 5.6 Central tube; 5.1.1 Opening piston, 5.1.2 Constant pressure opening valve, 5.1.3 Sliding sleeve, 5.2.1 Rotary ring cap, 5.2.2 Rotary ring, 5.2.3 Track pin, 5.2.4 Rotary ring cap spring, 5.3.1 Controller body, 5.3.2 Balance plug, 5.3.3 Balance spring, 5.4.1 Pressure relief device body, 5.4.2 Upper pressure relief channel, 5.4.3 Pressure relief valve, 5.4.4 Lower pressure relief hole, 5.5.1 Fracturing fluid external discharge hole, 5.6.1 Fracturing fluid internal discharge hole, 5.6.2 Track shallow groove, 5.6.3 Lower connector of central tube, 5.6.4 Circulating fluid port, 5.6.2.1 Long track, 5.6.2.2 Short track; 7.1 Packer upper connector, 7.2 Packer central tube, 7.3 Expanding rubber tube, 7.4 Rubber tube lower support sleeve, 7.5 Unsealing mechanism, 7.6 Setting seal inlet, 7.7 Rubber tube skeleton, 7.8 Packer lower connector, 7.5.1 Fixing ring, 7.5.2 Shear pin, 7.5.3 Locking ring; Hydraulic booster pump 11.1, three-position four-way solenoid directional valve 11.2, booster pipeline control valve 11.3, pressure relief control valve 11.4, pressure relief pipeline pressure gauge 11.5, fracturing fluid main pipeline 11.6, fracturing fluid main pipeline control valve 11.7, fracturing pump truck 11.8, fracturing fluid storage tank 11.9, supply pipeline 11.10, return pipeline 11.11; 11.1.1 Pressure boosting inlet, 11.1.2 Return inlet, 11.1.3 Fracturing fluid inlet, 11.1.4 Pressure relief port, 11.1.5 Wellhead connection flange, 11.1.6 Hydraulic cylinder body, 11.1.7 Return spring, 11.1.8 Fracturing fluid check valve, 11.1.9 Pressure boosting cylinder, 11.1.10 Pressure boosting piston, 11.1.11 Lifting ring. Detailed Implementation

[0016] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0017] Example 1, referring to Figures 1-10The present invention discloses a full-bore, switchable fracturing completion device, comprising a blind plug 3, a hydraulic production switch 6, a Y445 release packer 8, tubing 9, and a wellhead device 10. It further includes a constant-pressure one-way balance valve 4, a full-bore, unlimited-stage fracturing switch 5, a releaseable fracturing packer 7, and a surface wellhead fracturing booster device 11. The Y445 release packer 8 is connected via tubing 9. At the lower end of the Y445 release packer 8, one or more releaseable fracturing packers 7 are connected to isolate different reservoirs, and at the bottom... A blind plug 3 is installed at the end, located above the bottom of the artificial well 1. Between the two resealable fracturing packers 7, a full-bore unlimited-stage fracturing switch 5, a hydraulic oil production switch 6, and a constant-pressure one-way balance valve 4 are connected by tubing 9. A surface wellhead fracturing booster device 11 is installed at the surface wellhead. Full-bore fracturing is achieved through the full-bore unlimited-stage fracturing switch 5. The pressure of the fracturing fluid is increased through the surface wellhead fracturing booster device 11. Layered oil production is achieved through the hydraulic oil production switch 6. Pressure relief is achieved after fracturing through the constant-pressure one-way balance valve 4. Reference Figure 2 The surface wellhead fracturing booster device 11 mentioned in this invention includes a hydraulic booster pump 11.1, a three-position four-way solenoid directional valve 11.2, a booster pipeline control valve 11.3, a pressure relief control valve 11.4, a pressure relief pipeline pressure gauge 11.5, a fracturing fluid main pipeline 11.6, a fracturing fluid main pipeline control valve 11.7, a fracturing pump truck 11.8, a fracturing fluid storage tank 11.9, a supply pipeline 11.10, and a return pipeline 11.11. The upper part of the hydraulic booster pump 11.1 is connected by a three-position... The four-way solenoid directional valve 11.2, the booster pipeline control valve 11.3, and the supply pipeline 11.10 are connected to the fracturing pump truck 11.8. The return pipeline 11.11 connects to the fracturing fluid storage tank 11.9. In the middle of the supply pipeline 11.10, the main fracturing fluid pipeline 11.6 and the main fracturing fluid pipeline control valve 11.7 are connected to the middle of the hydraulic booster pump 11.1. The hydraulic booster pump 11.1 is equipped with a pressure relief control valve 11.4 and a pressure relief pipeline pressure gauge 11.5 on the lower middle side. Reference Figure 4 The full-bore infinite-stage fracturing switch 5 mentioned in this invention includes a fracturing switch 5.1, a fracturing switch tracker 5.2, a circulating fluid controller 5.3, a fracturing fluid pressure relief device 5.4, a cylinder liner body 5.5, and a central tube 5.6. The cylinder liner body 5.5 is installed outside the central tube 5.6. The fracturing fluid pressure relief device 5.4 is installed on the top of the cylinder liner body 5.5. The fracturing switch 5.1 is installed on the lower side of the fracturing fluid pressure relief device 5.4. The fracturing switch tracker 5.2 is installed below the fracturing switch 5.1. The circulating fluid controller 5.3 is installed at the lower part of the fracturing switch tracker 5.2.

[0018] Reference Figure 3The hydraulic booster pump 11.1 mentioned in this invention includes a booster inlet 11.1.1, a return inlet 11.1.2, a fracturing fluid inlet 11.1.3, a pressure relief port 11.1.4, a hydraulic cylinder body 11.1.6, a return spring 11.1.7, a fracturing fluid check valve 11.1.8, a booster cylinder 11.1.9, and a booster piston 11.1.10. The lower part of the booster cylinder 11.1.9... The lower end of the hydraulic cylinder body 11.1.6 is connected to the upper end of the hydraulic cylinder body 11.1.6, and the lower end of the hydraulic cylinder body 11.1.6 is fixedly connected to the wellhead connecting flange 11.1.5. The side wall of the booster cylinder 11.1.9 is provided with a booster inlet 11.1.1 and a return port 11.1.2 respectively. A booster piston 11.1.10 is installed in the inner cavity of the booster cylinder 11.1.9, and the upper surface area of ​​the booster piston 11.1.10 is... The surface area is larger than the lower end, allowing the booster piston 11.1.10 to move downwards quickly to achieve the boosting effect. The boosted fracturing fluid is then sprayed downwards along the fracturing fluid check valve 11.1.8, and a portion of the return fluid flows back to the fracturing fluid storage tank 11.9 along the return port 11.1.2. The upper side of the outer wall of the hydraulic cylinder body 11.1.6 is provided with a fracturing fluid inlet 11.1.3, and the middle and lower side is provided with a pressure relief port 11.1.4. A fracturing fluid check valve 11.1.8 is installed in the inner cavity of the hydraulic cylinder body 11.1.6, and a return spring 11.1.7 is installed on the lower side of the fracturing fluid check valve 11.1.8. The fracturing fluid check valve 11.1.8 plays a role in preventing reverse flow, thereby continuously increasing the pressure below. In addition, a lifting ring 11.1.11 is fixed at the top of the booster cylinder 11.1.9 for easy installation and lifting.

[0019] Reference Figures 4-6 The central tube 5.6 of the full-bore unlimited-stage fracturing switch 5 mentioned in this invention has a fracturing fluid internal drain hole 5.6.1 at its upper part and a fracturing fluid external drain hole 5.5.1 at its upper side of the cylinder liner body 5.5. A sliding sleeve 5.1.3 is installed inside the fracturing fluid external drain hole 5.5.1. A fracturing switch 5.1 is installed between the fracturing fluid internal drain hole 5.6.1 and the sliding sleeve 5.1.3. A shallow track groove 5.6.2 is provided on the outer wall of the middle part of the central tube 5.6. A circulation fluid port 5.6.4 is provided at the lower part of the central tube 5.6. A central tube lower connector 5.6.3 is provided at the bottom end.

[0020] The fracturing switch 5.1 includes an opening piston 5.1.1 and a constant pressure opening valve 5.1.2. The opening piston 5.1.1 is located in the annulus between the cylinder liner body 5.5 and the central tube 5.6. A liquid passage is provided in the center of the opening piston 5.1.1, and the constant pressure opening valve 5.1.2 is installed on the liquid passage. The upper surface area of ​​the opening piston 5.1.1 is larger than the lower surface area.

[0021] The aforementioned fracturing switch track device 5.2 includes a rotating cap 5.2.1, a rotating ring 5.2.2, a track pin 5.2.3, and a rotating cap spring 5.2.4. The upper end of the rotating cap 5.2.1 contacts the lower end of the sliding sleeve 5.1.3 and the constant pressure opening valve 5.1.2. The rotating cap spring 5.2.4 is installed at the lower end of the rotating cap 5.2.1. The rotating ring 5.2.2 is installed inside the rotating cap 5.2.1. The track pin 5.2.3 is installed on the rotating ring 5.2.2. The track pin 5.2.3 is connected to the track shallow groove 5.6.2 provided on the outer wall of the central tube 5.6.

[0022] Reference Figure 7 The shallow track groove 5.6.2 mentioned in this invention includes a long track 5.6.2.1 and a short track 5.6.2.2. When the track pin 5.2.3 is on the long track 5.6.2.1 under the drive of the rotating ring 5.2.2, the sliding sleeve 5.1.3 moves downward and the fracturing switch 5.1 is in the open state. When the pressure is reversed, the rotating ring 5.2.2 drives the track pin 5.2.3 to be located on the short track 5.6.2.2, the sliding sleeve 5.1.3 moves upward and the fracturing switch 5.1 is in the closed state, realizing unlimited-level on / off fracturing of the entire diameter.

[0023] The aforementioned circulating fluid controller 5.3 includes a controller body 5.3.1, a balance plug 5.3.2, and a balance spring 5.3.3. The upper end of the controller body 5.3.1 is a necked-up connector, which is threadedly connected to the lower end of the cylinder liner body 5.5. The balance plug 5.3.2 is installed in the annulus between the necked-up connector and the central tube 5.6 of the controller body 5.3.1. The balance spring 5.3.3 is installed at the lower end of the balance plug 5.3.2. The outer diameter of the balance plug 5.3.2 is the same as the inner diameter of the necked-up connector, and the inner diameter of the controller body 5.3.1 is larger than the inner diameter of the necked-up connector. When the balance plug 5.3.2 moves down into the lower part of the controller body 5.3.1, the circulating fluid communicates with the circulating fluid port 5.6.4 along the annulus between the controller body 5.3.1 and the central tube 5.6.

[0024] Furthermore, the aforementioned fracturing fluid pressure relief device 5.4 includes a pressure relief device body 5.4.1, an upper pressure relief channel 5.4.2, a pressure relief valve 5.4.3, and a lower pressure relief hole 5.4.4. The pressure relief device body 5.4.1 is installed on the top of the cylinder liner body 5.5 and the central tube 5.6. The inner wall of the pressure relief device body 5.4.1 is threadedly connected to the top of the central tube 5.6, and the outer wall of the pressure relief device body 5.4.1 is threadedly connected to the top of the cylinder liner body 5.5. The pressure relief device body 5.4.1 has an upper pressure relief channel 5.4.2 inside, and a pressure relief valve 5.4.3 is installed inside the upper pressure relief channel 5.4.2. The bottom of the pressure relief valve 5.4.3 has a lower pressure relief hole 5.4.4, which communicates with the annulus of the cylinder liner body 5.5 and the central tube 5.6 through the lower pressure relief hole 5.4.4, and is used to assist in pressure relief when pressure relief is required.

[0025] Reference Figures 8-9 The constant pressure one-way balancing valve 4 mentioned in this invention includes a balancing valve body 4.1, a main pressure relief channel 4.2, a constant pressure plug 4.3, a constant pressure spring 4.4, a pressure adjusting screw 4.5, and an inner pressure relief hole 4.6. The main pressure relief channel 4.2 is provided inside the outer wall of the balancing valve body 4.1, and the outer end of the main pressure relief channel 4.2 connects to the outer wall surface of the balancing valve body 4.1. A pressure relief valve seat is provided inside the main pressure relief channel 4.2, and the constant pressure plug 4.3 is installed under the pressure relief valve seat. A pressure-reducing spring 4.4 is installed at the lower part, and a pressure-adjusting screw 4.5 is installed at the lower end of the pressure-reducing spring 4.4; an internal pressure relief hole 4.6 is provided in the middle of the inner wall of the balance valve body 4.1, one end of the internal pressure relief hole 4.6 is connected to the inner wall surface of the balance valve body 4.1, and the other end is connected to the pressure-reducing plug 4.3 in the main pressure relief channel 4.2; in addition, an upper connector internal thread 4.7 is provided at the upper end of the balance valve body 4.1, and a lower connector internal thread 4.8 is provided at the lower end for easy installation and connection.

[0026] Reference Figure 10The resealable fracturing packer 7 mentioned in this invention includes a packer upper connector 7.1, a packer central tube 7.2, an expanding rubber tube 7.3, a rubber tube lower support sleeve 7.4, a release mechanism 7.5, a setting inlet 7.6, a rubber tube skeleton 7.7, and a packer lower connector 7.8. The packer central tube 7.2 has a setting inlet 7.6 at its upper part. The upper end of the packer central tube 7.2 is connected to the packer upper connector 7.1, and the lower end has a packer lower connector 7.8. The rubber tube lower support sleeve 7.4 is installed above the packer lower connector 7.8. The expanding rubber tube 7.3 is installed between the packer upper connector 7.1 and the rubber tube lower support sleeve 7.4, and the lower end of the expanding rubber tube 7.3 is connected to the packer upper connector 7.1. An unsealing mechanism 7.5 is installed between the lower support sleeve 7.4 of the expansion tube 7.3. The expansion tube 7.3 has a tube frame 7.7 inside. The unsealing mechanism 7.5 includes a fixing ring 7.5.1, a shearing pin 7.5.2, and a locking ring 7.5.3. The lower end of the expansion tube 7.3 is connected to the fixing ring 7.5.1. The fixing ring 7.5.1 and the locking ring 7.5.3 are connected by the shearing pin 7.5.2. During sealing, the locking ring 7.5.3 fixes and supports the fixing ring 7.5.1. During unsealing, lifting the unsealed fracturing packer 7 releases the packer. After the shearing pin 7.5.2 is cut, the fixing ring 7.5.1 at the lower end of the expansion tube 7.3 disengages from the locking ring 7.5.3, thereby achieving unsealing.

[0027] In addition, the hydraulic oil production switch 6 mentioned in this invention is a conventional technology well known to those skilled in the art, enabling fracturing and oil production to be carried out in one operation without the need for multiple constructions, thus reducing operating costs. Furthermore, during oil production, the oil flows unidirectionally towards the central tube of the hydraulic oil production switch 6, which is exactly opposite to the flow direction of the fracturing fluid in the wellhead fracturing booster device 11. Since the two flow directions are opposite, the problem of the oil production channel opening during fracturing and the fracturing channel opening during oil production will not occur.

[0028] The well completion method of the full-bore switchable fracturing completion device mentioned in this invention includes the following steps: I. Assemble the full-bore switchable fracturing completion device: Install the surface wellhead fracturing booster device 11 at the surface wellhead, and lower the Y445 drop-off packer 8 through the tubing 9. Connect three releaseable fracturing packers 7 to the lower end of the Y445 drop-off packer 8 to isolate the three reservoirs, and install a blind plug 3 at the bottom. Connect the full-bore unlimited-stage fracturing switch 5, the hydraulic production switch 6, and the constant pressure one-way balance valve 4 between the two releaseable fracturing packers 7 through the tubing 9. Among them, the fracturing switch rail 5.2 of the first-stage full-bore unlimited-stage fracturing switch 5 is located at the long rail 5.6.2.1, so that the fracturing switch 5.1 is in the downward one-way open state. The fracturing switch rail 5.2 of the second and third-stage full-bore unlimited-stage fracturing switches 5 is located at the short rail 5.6.2.2, so that the fracturing switch 5.1 is in the closed state. 2. Pressurized fluid is injected into tubing 9 through surface wellhead fracturing booster device 11. The pressurized fluid enters Y445 release packer 8 along tubing 9 to achieve setting. Then, the fluid continues to flow downward to set one or more releaseable fracturing packers 7. 3. Begin fracturing operations on the three reservoirs sequentially: The fracturing pump truck 11.8 in the surface wellhead fracturing booster unit 11 continues to pressurize. The fracturing fluid in the fracturing fluid storage tank 11.9 flows along the supply line 11.10, and a portion of the fracturing fluid flows along the three-position four-way solenoid directional valve 11.2 into the booster inlet 11.1.1 of the hydraulic booster pump 11.1, pushing the booster piston 11.1.10 to move rapidly downwards. The return fluid under the booster piston 11.1.10 flows along the return... The fracturing fluid flows back to the fracturing fluid storage tank 11.9 through the fluid inlet 11.1.2, the three-position four-way solenoid directional valve 11.2, and the return line 11.11. Another portion of the fracturing fluid enters the fracturing fluid inlet 11.1.3 along the main fracturing fluid line 11.6, where it is further pressurized by the booster piston 11.1.10. The pressurized fracturing fluid pushes open the fracturing fluid check valve 11.1.8 and enters the tubing 9. It then travels along the tubing to the first-stage full-bore unlimited-stage fracturing switch 5. The activated fracturing switch 5.1 enters the first reservoir to achieve continuous fracturing, maintaining a stable fracturing fluid pressure at the fracturing fluid inlet 11.1.3. During this time, the pressure gauge 11.5 in the relief line continuously rises until it exhibits significant fluctuations, indicating that the rock in the first reservoir has been crushed. Once the pressure gauge 11.5 drops to a certain stable value, the fracturing of the first reservoir is complete. Then, after diffusion is complete, the relief port 1 is opened again. 1.1.4 The fracturing fluid in tubing 9 is drained, the main pressure relief channel 4.2 in the constant pressure one-way balance valve 4 is opened, and the liquid in the first reservoir is depressurized along the main pressure relief channel 4.2 and the inner pressure relief hole 4.6; in addition, the fracturing switch tracker 5.2 in the first-stage full-bore unlimited fracturing switch 5 moves to the short track 5.6.2.2, so that the fracturing switch 5.1 enters the closed state, and the fracturing fluid pressure relief device 5.4 is in the depressurization state. Finally, the depressurization work of the first reservoir is completed. The fracturing fluid is then pressurized again through the surface wellhead fracturing booster device 11, so that the fracturing switch tracker 5.2 of the full-bore unlimited-stage fracturing switch 5 for the second reservoir is at the long track 5.6.2.1, and the fracturing switch 5.1 is in the open state. The fracturing switch trackers 5.2 of the full-bore unlimited-stage fracturing switch 5 for the first and third reservoirs are at the short track 5.6.2.2, and both fracturing switches 5.1 are in the closed state. Then, fracturing is performed on the second reservoir. After fracturing is completed, the pressure in the second reservoir is released. The same process is repeated for the third reservoir. After fracturing is completed, the pressure is released again. IV. After fracturing the three reservoirs separately, the Y445 release packer 8 is released by pressurization, the upper tubing string is pulled to the surface, the surface wellhead fracturing booster device 11 is removed, and the production equipment is installed, referring to... Figure 11 Then, the oil pump 12 is lowered into the tubing 9 for stratified oil production. When oil production is needed for the first reservoir, pressure is applied to the casing 2 through the wellhead device 10. The hydraulic oil production switch 6 for the first reservoir is in a one-way upward opening state, while the hydraulic oil production switches 6 for the second and third reservoirs are in a closed state. At this time, the first reservoir is produced by the operation of the oil pump 12. When oil production is needed for the second reservoir, pressure is applied to the casing 2 through the wellhead device 10. The hydraulic oil production switch 6 for the second reservoir is in a one-way upward opening state, while the hydraulic oil production switches 6 for the first and third reservoirs are in a closed state. At this time, the second reservoir is produced by the operation of the oil pump 12. Oil production is carried out sequentially for the third reservoir, thus achieving stratified production of the three reservoirs downhole.

[0029] Example 2: The present invention provides a full-bore, switchable fracturing completion device, including a blind plug 3, a hydraulic production switch 6, a Y445 release packer 8, tubing 9, and a wellhead device 10. It also includes a constant-pressure one-way balance valve 4, a full-bore, unlimited-stage fracturing switch 5, a releaseable fracturing packer 7, and a surface wellhead fracturing booster device 11. The Y445 release packer 8 is connected via tubing 9, and at the lower end of the Y445 release packer 8, one or more releaseable fracturing packers 7 are connected to achieve fracturing completion in various reservoirs. The system is isolated and a blind plug 3 is installed at the bottom. Between the two resealable fracturing packers 7, a full-bore unlimited-stage fracturing switch 5, a hydraulic oil production switch 6, and a constant-pressure one-way balance valve 4 are connected by tubing 9. A surface wellhead fracturing booster device 11 is installed at the surface wellhead. Full-bore fracturing is achieved through the full-bore unlimited-stage fracturing switch 5. The pressure of the fracturing fluid is increased through the surface wellhead fracturing booster device 11. Layered oil production is achieved through the hydraulic oil production switch 6. The pressure relief after fracturing is achieved through the constant-pressure one-way balance valve 4.

[0030] The difference from Example 1 is: The full-bore unlimited-stage fracturing switch 5 mentioned in this invention includes a fracturing switch 5.1, a fracturing switch tracker 5.2, a circulating fluid controller 5.3, a cylinder liner body 5.5, and a central tube 5.6. The cylinder liner body 5.5 is installed outside the central tube 5.6. An upper connector is installed on the top of the cylinder liner body 5.5. The fracturing switch 5.1 is installed on the lower side of the upper connector. The fracturing switch tracker 5.2 is installed below the fracturing switch 5.1. The circulating fluid controller 5.3 is installed at the lower part of the fracturing switch tracker 5.2.

[0031] The above description is merely a partial preferred embodiment of the present invention. Any person skilled in the art can modify the above-described technical solutions or modify them into equivalent technical solutions. Therefore, any simple modifications or equivalent transformations made based on the technical solutions of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A full-bore switchable fracturing completion device, comprising a blind plug (3), a hydraulic production switch (6), a Y445 drop-out packer (8), tubing (9), and wellhead assembly (10), characterized in that: It also includes a constant pressure one-way balance valve (4), a full-bore unlimited-stage fracturing switch (5), a resealable fracturing packer (7), and a surface wellhead fracturing booster device (11). It is connected to a Y445 drop-off packer (8) through a tubing (9). At the lower end of the Y445 drop-off packer (8), a resealable fracturing packer (7) of one or more stages is connected to achieve isolation of each reservoir. A blind plug (3) is installed at the bottom. Between the two resealable fracturing packers (7), a full-bore unlimited-stage fracturing switch (5), a hydraulic oil production switch (6), and a constant pressure one-way balance valve (4) are connected through a tubing (9). A surface wellhead fracturing booster device (11) is installed at the surface wellhead. Full-bore fracturing is achieved through the full-bore unlimited-stage fracturing switch (5). The pressure of the fracturing fluid is increased through the surface wellhead fracturing booster device (11). Layered oil production is achieved through the hydraulic oil production switch (6). Pressure relief after fracturing is achieved through the constant pressure one-way balance valve (4). The surface wellhead fracturing booster unit (11) includes a hydraulic booster pump (11.1), a three-position four-way solenoid directional valve (11.2), a booster pipeline control valve (11.3), a pressure relief control valve (11.4), a pressure relief pipeline pressure gauge (11.5), a fracturing fluid main pipeline (11.6), a fracturing fluid main pipeline control valve (11.7), a fracturing pump truck (11.8), a fracturing fluid storage tank (11.9), a supply pipeline (11.10), and a return pipeline (11.11). The upper part of the hydraulic booster pump (11.1) is connected by a three-position four-way valve. The electromagnetic reversing valve (11.2), the booster line control valve (11.3), and the fluid supply line (11.10) are connected to the fracturing pump truck (11.8) and connected to the fracturing fluid storage tank (11.9) through the return line (11.11). In the middle of the fluid supply line (11.10), it is connected to the middle of the hydraulic booster pump (11.1) through the fracturing fluid main line (11.6) and the fracturing fluid main line control valve (11.7). The hydraulic booster pump (11.1) is equipped with a pressure relief control valve (11.4) and a pressure relief line pressure gauge (11.5) on the lower middle side. The full-bore unlimited-stage fracturing switch (5) includes a fracturing switch (5.1), a fracturing switch tracker (5.2), a circulating fluid controller (5.3), a fracturing fluid pressure relief device (5.4), a cylinder liner body (5.5), and a central tube (5.6). The cylinder liner body (5.5) is installed outside the central tube (5.6). The fracturing fluid pressure relief device (5.4) is installed on the top of the cylinder liner body (5.5). The fracturing switch (5.1) is installed on the lower side of the fracturing fluid pressure relief device (5.4). The fracturing switch tracker (5.2) is installed below the fracturing switch (5.1). The circulating fluid controller (5.3) is installed at the lower part of the fracturing switch tracker (5.2).

2. The full-bore switchable fracturing and completion device according to claim 1, characterized in that: The hydraulic booster pump (11.1) includes a booster inlet (11.1.1), a return inlet (11.1.2), a fracturing fluid inlet (11.1.3), a pressure relief port (11.1.4), a hydraulic cylinder body (11.1.6), a return spring (11.1.7), a fracturing fluid check valve (11.1.8), a booster cylinder (11.1.9), and a booster piston (11.1.10). The lower end of the booster cylinder (11.1.9) is connected to the hydraulic cylinder body (11.1.6), and the lower end of the hydraulic cylinder body (11.1.6) is fixedly connected to the wellhead connecting flange (11.1.5). The sidewalls of the booster cylinder (11.1.9) are respectively provided with booster inlets (11.1.1, 11.1.2, 11.1.3, 11.1.4), a hydraulic cylinder body (11.1.5), a hydraulic cylinder body (11.1.6), a hydraulic cylinder body (11.1.6), a hydraulic cylinder body (11.1.3), a hydraulic cylinder body (11.1.4), a hydraulic cylinder body (11.1.5), and a hydraulic cylinder piston (11.1.10). 11.1.1) and return port (11.1.2), a booster piston (11.1.10) is installed in the inner cavity of the booster cylinder (11.1.9), the upper surface area of ​​the booster piston (11.1.10) is larger than the lower surface area; the upper side of the outer wall of the hydraulic cylinder body (11.1.6) is provided with a fracturing fluid inlet (11.1.3), and the middle and lower side is provided with a pressure relief port (11.1.4). A fracturing fluid check valve (11.1.8) is installed in the inner cavity of the hydraulic cylinder body (11.1.6), and a return spring (11.1.7) is installed on the lower side of the fracturing fluid check valve (11.1.8).

3. The full-bore switchable fracturing and completion device according to claim 2, characterized in that: The upper part of the central tube (5.6) of the full-bore unlimited-stage fracturing switch (5) is provided with a fracturing fluid internal discharge hole. 5.6.1), a fracturing fluid drain hole is provided on the upper side of the cylinder liner body (5.5). 5.5.1), a sliding sleeve (5.1.3) shall be installed inside the fracturing fluid external drain hole (5.5.1); in the fracturing fluid internal drain hole ( A fracturing switch (5.1) is installed between the sliding sleeve (5.1.3) and the central tube (5.6). The central tube (5.6) has a shallow track groove (5.6.2) on its outer wall, a circulating fluid port (5.6.4) at its lower part, and a central tube lower connector (5.6.3) at its bottom end.

4. The full-bore switchable fracturing and completion device according to claim 3, characterized in that: The fracturing switch (5.1) includes an opening piston (5.1.1) and a constant pressure opening valve (5.1.2). The opening piston (5.1.1) is located in the annulus between the cylinder liner body (5.5) and the central tube (5.6). A liquid passage is provided in the center of the opening piston (5.1.1), and the constant pressure opening valve (5.1.2) is installed on the liquid passage. The upper surface area of ​​the opening piston (5.1.1) is larger than the lower surface area.

5. The full-bore switchable fracturing and completion device according to claim 4, characterized in that: The fracturing switch track device (5.2) includes a rotating cap (5.2.1), a rotating ring (5.2.2), a track pin (5.2.3), and a rotating cap spring (5.2.4). The upper end of the rotating cap (5.2.1) contacts the lower end of the sliding sleeve (5.1.3) and the constant pressure opening valve (5.1.2). The rotating cap spring (5.2.4) is installed at the lower end of the rotating cap (5.2.1). The rotating ring (5.2.2) is installed inside the rotating cap (5.2.1). The track pin (5.2.3) is installed on the rotating ring (5.2.2). The track pin (5.2.3) is connected to the track shallow groove (5.6.2) provided on the outer wall of the central tube (5.6).

6. The full-bore switchable fracturing and completion device according to claim 5, characterized in that: The circulating fluid controller (5.3) includes a controller body (5.3.1), a balance plug (5.3.2), and a balance spring (5.3.3). The upper end of the controller body (5.3.1) is a necked-up connector, which is threadedly connected to the lower end of the cylinder liner body (5.5). The balance plug (5.3.2) is installed in the annulus between the necked-up connector and the central tube (5.6) of the controller body (5.3.1). The balance spring (5.3.3) is installed at the lower end of the balance plug (5.3.2). The outer diameter of the balance plug (5.3.2) is the same as the inner diameter of the necked-up connector, and the inner diameter of the controller body (5.3.1) is larger than the inner diameter of the necked-up connector. When the balance plug (5.3.2) moves down into the lower side of the controller body (5.3.1), the circulating fluid communicates with the circulating fluid port (5.6.4) along the annulus between the controller body (5.3.1) and the central tube (5.6).

7. The full-bore switchable fracturing and completion device according to claim 6, characterized in that: The fracturing fluid pressure relief device (5.4) includes a pressure relief device body (5.4.1), an upper pressure relief channel (5.4.2), a pressure relief valve (5.4.3), and a lower pressure relief port (5.4.4). The pressure relief device body (5.4.1) is installed on top of the cylinder liner body (5.5) and the central tube (5.6). The inner wall of the pressure relief device body (5.4.1) is threadedly connected to the top of the central tube (5.6). .1) The outer wall is threaded to the top of the cylinder liner body (5.5); the pressure relief body (5.4.1) is provided with an upper pressure relief channel (5.4.2), and a pressure relief valve (5.4.3) is installed in the upper pressure relief channel (5.4.2). The bottom of the pressure relief valve (5.4.3) is provided with a lower pressure relief hole (5.4.4), which is connected to the annulus of the cylinder liner body (5.5) and the central tube (5.6) through the lower pressure relief hole (5.4.4).

8. The full-bore switchable fracturing and completion device according to claim 7, characterized in that: The constant pressure one-way balancing valve (4) includes a balancing valve body (4.1), a main pressure relief channel (4.2), a constant pressure plug (4.3), a constant pressure spring (4.4), a pressure adjusting screw (4.5), and an inner pressure relief hole (4.6). The main pressure relief channel (4.2) is provided inside the outer wall of the balancing valve body (4.1), and the outer end of the main pressure relief channel (4.2) is connected to the outer wall surface of the balancing valve body (4.1). A pressure relief valve seat is provided inside the main pressure relief channel (4.2). A pressure-setting plug (4.3) is installed under the pressure relief valve seat, and a pressure-setting spring (4.4) is installed at the lower part of the pressure-setting plug (4.3). An adjusting screw (4.5) is installed at the lower end of the pressure-setting spring (4.4). An internal pressure relief hole (4.6) is provided in the middle of the inner wall of the balance valve body (4.1). One end of the internal pressure relief hole (4.6) is connected to the inner wall surface of the balance valve body (4.1), and the other end is connected to the pressure-setting plug (4.3) in the main pressure relief channel (4.2).

9. The full-bore switchable fracturing and completion device according to claim 8, characterized in that: The resealable fracturing packer (7) includes an upper packer connector (7.1), a packer central tube (7.2), an expanding rubber tube (7.3), a rubber tube lower support sleeve (7.4), a release mechanism (7.5), a setting inlet (7.6), a rubber tube skeleton (7.7), and a lower packer connector (7.8). The upper part of the packer central tube (7.2) is provided with a setting inlet (7.6). The upper end of the packer central tube (7.2) is connected to the upper packer connector (7.1), and the lower end is provided with the lower packer connector (7.8). The rubber tube lower support sleeve (7.4) is installed above the lower packer connector (7.8). An expanding rubber tube (7.3) is installed between the upper connector (7.1) of the separator and the lower support sleeve (7.4) of the rubber tube, and an unsealing mechanism (7.5) is installed between the lower end of the expanding rubber tube (7.3) and the lower support sleeve (7.4). The expanding rubber tube (7.3) has a rubber tube skeleton (7.7) inside. The unsealing mechanism (7.5) includes a fixing ring (7.5.1), a shearing pin (7.5.2), and a locking ring (7.5.3). The lower end of the expanding rubber tube (7.3) is connected to the fixing ring (7.5.1), and the fixing ring (7.5.1) and the locking ring (7.5.3) are connected by the shearing pin (7.5.2).

10. The well completion method of the full-bore switchable fracturing completion device according to claim 9, characterized in that: Includes the following processes:

1. Assemble the full-bore switchable fracturing completion device: Install the surface wellhead fracturing booster device (11) at the surface wellhead, and lower the Y445 drop-out packer (8) through the tubing (9). Connect three releaseable fracturing packers (7) to the lower end of the Y445 drop-out packer (8) to achieve isolation of the three reservoirs, and install a blind plug (3) at the bottom. Connect the full-bore unlimited-stage fracturing switch (5) and hydraulic system between the two releaseable fracturing packers (7) through the tubing (9). The oil production switch (6) and the constant pressure one-way balance valve (4) are provided. The fracturing switch tracker (5.2) of the first-stage full-bore infinite fracturing switch (5) is located on the long track (5.6.2.1), so that the fracturing switch (5.1) is in the downward one-way open state. The fracturing switch tracker (5.2) of the second-stage and third-stage full-bore infinite fracturing switches (5) is located on the short track (5.6.2.2), so that the fracturing switch (5.1) is in the closed state.

2. Pressurized liquid is injected into the tubing (9) through the surface wellhead fracturing booster device (11). The pressurized liquid enters the Y445 release packer (8) along the tubing (9) to achieve setting. Then, the liquid continues to flow downward to set one or more releaseable fracturing packers (7).

3. Start fracturing operations on the three reservoirs in sequence: The fracturing pump truck (11.8) in the surface wellhead fracturing booster unit (11) continues to boost pressure. The fracturing fluid in the fracturing fluid storage tank (11.9) flows along the supply pipeline (11.10), and a portion of the fracturing fluid flows along the three-position four-way solenoid directional valve (11.2) into the booster inlet (11.1.1) of the hydraulic booster pump (11.1), pushing the booster piston (11.1.10) to move downwards. The return fluid under the booster piston (11.1.10) flows along the return fluid... The fracturing fluid flows back to the fracturing fluid storage tank (11.9) through the inlet (11.1.2), the three-position four-way solenoid directional valve (11.2), and the return line (11.11). Another part of the fracturing fluid enters the fracturing fluid inlet (11.1.3) along the main fracturing fluid line (11.6), where it is further pressurized by the booster piston (11.1.10) above. The pressurized fracturing fluid pushes open the fracturing fluid check valve (11.1.8) and enters the tubing (9), and then along the tubing (9) to the first-stage full-bore unlimited-stage fracturing switch (5). The fracturing fluid is introduced into the first reservoir through the opened fracturing switch (5.1) to achieve continuous fracturing and maintain a stable fracturing fluid pressure at the fracturing fluid inlet (11.1.3). At this time, the pressure gauge (11.5) in the pressure relief line continuously rises until it swings significantly, indicating that the rocks in the first reservoir have been crushed. When the pressure gauge (11.5) in the pressure relief line drops to a certain value and stabilizes, it indicates that the fracturing of the first reservoir is complete. Then, after diffusion is completed, the pressure relief port (11.1) is opened again. 4) The fracturing fluid in the tubing (9) is drained, the main pressure relief channel (4.2) in the constant pressure one-way balance valve (4) is opened, and the liquid in the first reservoir is depressurized along the main pressure relief channel (4.2) and the inner pressure relief hole (4.6); in addition, the fracturing switch tracker (5.2) in the first stage full-bore unlimited fracturing switch (5) comes to the short track (5.6.2.2), so that the fracturing switch (5.1) enters the closed state, and the fracturing fluid pressure relief device (5.4) is in the depressurization state. Finally, the depressurization work of the first reservoir is completed. The fracturing fluid is then pressurized again through the surface wellhead fracturing booster device (11), so that the fracturing switch tracker (5.2) of the full-bore unlimited-stage fracturing switch (5) of the second reservoir is in the long track (5.6.2.1), so that the fracturing switch (5.1) is in the open state, and the fracturing switch trackers (5.2) of the full-bore unlimited-stage fracturing switch (5) of the first and third reservoirs are in the short track (5.6.2.2), so that the two fracturing switches (5.1) are in the closed state. Then the fracturing operation is carried out on the second reservoir, and the pressure is released after the fracturing is completed. The fracturing operation is carried out on the third reservoir in turn, and the pressure is released after the fracturing is completed.

4. After the fracturing of the three reservoirs is completed, the Y445 release packer (8) is released by pressurization, the upper tubing string is pulled to the surface, the surface wellhead fracturing booster device (11) is removed, the oil production device is installed, and then the oil pump (12) is lowered into the tubing (9) for stratified oil production. When it is necessary to produce oil from the first reservoir, the casing (2) is pressurized through the wellhead device (10). The hydraulic oil production switch (6) of the first reservoir is in the upward one-way open state, and the hydraulic oil production switches (6) of the second and third reservoirs are in the upward one-way open state. 6) When the well is in the closed state, the first reservoir is exploited by the operation of the oil pump (12); when the second reservoir needs to be exploited, the wellhead device (10) pressurizes the casing (2), the hydraulic oil production switch (6) of the second reservoir is in the upward one-way open state, and the hydraulic oil production switches (6) of the first reservoir and the third reservoir are in the closed state. At this time, the second reservoir is exploited by the operation of the oil pump (12); the third reservoir is exploited in sequence, and the three reservoirs in the well are exploited in layers.

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