Thickened oil viscosity reduction, filling and sand prevention integrated pipe column and method
By using an integrated tubing string for heavy oil viscosity reduction, filling, sand control, and production, and utilizing a casing structure and hydraulic control, high-efficiency production of heavy oil wells has been achieved. This solves the problem of complex filling, sand control, viscosity reduction, and energy enhancement processes, and achieves long-term sand control and viscosity reduction effects without moving the tubing string.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2022-07-19
- Publication Date
- 2026-06-23
AI Technical Summary
Existing technologies cannot achieve efficient production in heavy oil wells. The processes of filling for sand control and viscosity reduction to enhance energy are complex and prone to causing reservoir contamination. Furthermore, sand production during production affects the lifespan of the tubing string, resulting in complex operations and high costs.
The integrated tubing for heavy oil viscosity reduction, filling, and sand control is adopted. The tubing is lowered into the system in one go through a casing structure. Combined with hydraulic control, it completes heavy oil viscosity reduction, filling, sand control, and long-term sand blocking. It uses viscosity reducers such as CO2 and gravel to form a sand barrier, enabling production without moving the tubing.
The process was simplified, production efficiency was improved, operational steps were reduced, and well fluid damage and cold damage were minimized, enabling efficient and long-term production of heavy oil reservoirs.
Smart Images
Figure CN117468897B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of petroleum equipment technology, specifically to an integrated tubing string and method for heavy oil viscosity reduction, filling, and sand control production. Background Technology
[0002] For sandstone reservoirs producing sand, to ensure long-term production of oil and gas wells, gravel packing for sand control is necessary first. After retrieving the packing tubing, production tubing is then run in for production. In other words, sand control and oil production are two independent processes or procedures. For some heavy oil reservoirs, due to lower formation pressure and higher crude oil viscosity, in addition to the above two processes, CO2 injection for viscosity reduction and energy enhancement for cold production, or steam injection for viscosity reduction and energy enhancement for hot production, is also required. If CO2 or steam is injected first, followed by sand control, for operational safety, the pressure and heat from the energy enhancement need to be released before subsequent sand control, resulting in a sharp reduction in viscosity reduction and energy enhancement effects. If sand control is performed first, and the packing tubing is retrieved before injecting CO2 for viscosity reduction and energy enhancement for cold production, or steam for viscosity reduction and energy enhancement for hot production, the sand-carrying fluid used for sand control will be pushed into the deeper layers of the oil reservoir, causing contamination and cold damage, which is detrimental to accurate oil testing and efficient production in heavy oil thermal recovery wells. Furthermore, if existing sand-control process tubing is used without removing the inner tubing for oil production, the sand-control channels will not be effectively closed. During production, the screen sleeve or formation sand will be expelled back into the production tubing or pump barrel under the negative pressure of the production fluid flow, affecting the lifespan of the production tubing. It can also cause sand to bury the inner tubing and tools, or sand to jam the tubing, making it impossible to remove the inner tubing normally in the later stages, resulting in major overhaul operations.
[0003] Prior to filing this invention application, the inventors conducted a search for relevant patents in the prior art, and three representative prior art patents were identified, as follows:
[0004] 1. The authorized announcement number is CN101929329B, named "Horizontal Well Screen Pipe Gravel Packing Sand Control Device". Its disclosed technical solution includes a sealing body (21), casing (3), valve body (56) of filling valve (5), connector (6), and screen pipe (8) which are fixedly connected from top to bottom; the upper end of the inner sleeve (52) of filling valve (5) is fixedly connected to the valve body (41) of acid washing valve (4), and the lower end is fixedly connected to the inner tube (7); a sealing pipe (1) is installed in the inner hole of sealing body (21); a sealing ring (22) is installed between the inner hole boss of sealing body (21) and sealing pipe (1); there is a gap between the sealing pipe (1) above sealing ring (22) and the inner hole of sealing body (21). It can be seen from its disclosed solution that although it can achieve the requirements of acid washing, gravel packing, and backwashing in one well completion string, it needs to be removed before oil production operation and cannot further simplify the filling sand control process.
[0005] 2. Application No. CN110847874A, entitled "A Fracturing and Sand-Removing String and Method," primarily addresses the issue of minimizing slurry in the drill pipe after sand removal by controlling the discharge rate. This minimizes the risk of the sand control service string getting stuck in the well while ensuring sand removal. The invention involves stopping sand injection at the surface after ensuring the designed pumping rate reaches the target amount, replacing the expanded clay aggregate, and then inducing fracture closure by reducing the discharge rate and opening the annular bypass channel. This allows the expanded clay aggregate to fill the annulus screen. This method results in less expanded clay aggregate in the wellbore after sand removal, significantly reducing reverse circulation resistance and enabling rapid establishment of a reverse circulation path after sand removal. This reduces the risk of tool jamming and improves the success rate of the operation. While its main technical objective is to facilitate sand removal, similar to the aforementioned prior art, it does not further simplify the sand control filling process.
[0006] 3. The authorized announcement number CN107524426B, entitled "Filling String," discloses a technical solution comprising an outer string and an inner string, with the inner string installed inside the outer string. The outer string includes, from top to bottom, a top packer, a filling sleeve, a screen tube, and an insertion seal, connected sequentially. The inner string includes a central tube, an inner tube, and, from top to bottom, a setting tool with a ball seat, a filling tool with a filling channel, a sealing ball seat, a leak-proof valve with an elastic sleeve, a sleeve switch tool, and a bottom seal. The filling tool, sealing ball seat, and leak-proof valve are sequentially installed inside the central tube, and the sleeve switch tool is installed on the central tube. This filling string has a simplified structure, eliminating the need for two layers of flushing tubing and a locator. It is easy to operate, significantly improves safety, and allows for a substantial increase in the inner diameter of the outer string, facilitating subsequent stratified injection and production techniques and enabling the implementation of the functions of filling tools in related technologies. It can be seen that although it simplifies the structure of the filling tubing, it still cannot achieve the integrated process of filling, sand control, cleaning, and oil production advocated in this application.
[0007] Therefore, in order to achieve efficient production from heavy oil wells and simplify the construction process, this invention application is hereby submitted. Summary of the Invention
[0008] This invention provides an integrated tubing string and method for heavy oil viscosity reduction, filling, and sand control production. Through the sleeve-type structure, the complexity of the process can be greatly reduced, thereby improving production efficiency.
[0009] To achieve the above objectives, the present invention provides the following technical solution:
[0010] An integrated tubing string for heavy oil viscosity reduction, filling, and sand control production includes:
[0011] The casing is installed inside the oil well and inserted into the oil layer, allowing it to communicate with the oil layer;
[0012] The screen tube is sealed to the bottom of the oil pipe via a sealing plug, and its lower part is provided with screen holes;
[0013] An oil pipe is installed inside the casing, and an internal circulation port is provided at the lower part of the oil pipe;
[0014] A filling inner tube is sleeved on the oil pipe, and its two ends are sealed to the oil pipe. A first annulus is formed between the oil pipe, the filling inner tube, the screen tube and the sleeve. A second annulus is formed between the filling inner tube and the oil pipe. An external circulation port is opened at the upper end of the filling inner tube. The external circulation port is used to connect the first annulus and the second annulus.
[0015] A flushing pipe is installed inside the screen tube, and its upper end is sealed to the inner wall of the screen tube.
[0016] A packer is installed on the filling inner tube below the external circulation port, and can seal the first annulus when open;
[0017] A filling sleeve is provided below the inner circulation port of the oil pipe, and it has a filling hole that can connect the inside of the oil pipe and the first annulus.
[0018] A steel ball and a sliding sleeve are disposed inside the oil pipe. The sliding sleeve is disposed below the steel ball to prevent it from sinking. The sliding sleeve is sealed to the oil pipe and can slide inside the oil pipe to block the filling hole.
[0019] A one-way sealer is fitted onto the inner filling tube below the filling sleeve to seal the first annulus below it.
[0020] As a preferred embodiment of the present invention, it further includes a bottom ball and a ball seat, wherein the ball seat is disposed at the upper end of the punch tube and prevents the bottom ball from sinking.
[0021] As a preferred embodiment of the present invention, the one-way sealer is a downward-facing leather cup and a leather cup cap. The leather cup is in a contracted state inside the leather cup cap, and opens to seal the first annular space below it when it is separated from the leather cup cap.
[0022] This invention also discloses a method for producing heavy oil with viscosity reduction, filling, and sand control using the aforementioned integrated heavy oil viscosity reduction, filling, and sand control tubing, comprising the following steps:
[0023] S1, tubing inserted into the well
[0024] After all the components of the tubing string are installed, except for the steel ball, they are lowered into the casing through the oil pipe, with the screen tube facing the oil layer. At this time, the sliding sleeve closes the filling hole, and the cup contracts under the restriction of the cup cap, so it does not rub against the inner wall of the casing.
[0025] S2, Throw the ball, sit down, open the filling port.
[0026] The steel ball is placed into the tubing and naturally sinks onto the sliding sleeve under gravity. Pressurization is applied inside the tubing, and the packer unfolds and sets under pressure, achieving the sealing of the first annulus. As pressure continues to be applied, the sliding sleeve and steel ball descend, exposing the filling port and opening the filling channel.
[0027] S3, viscosity reducers with energy-enhancing effects such as CO2 injection.
[0028] A viscosity reducer with energy-enhancing effects, such as CO2, is injected into the tubing. The viscosity reducer enters the first annulus at the bottom of the packer through the filling port and then enters the oil layer through the casing, thereby enhancing the energy and reducing the viscosity of the heavy oil in the oil layer.
[0029] S4, Extrusion Filling Sand Control
[0030] Following the previous step, gravel and sand-carrying fluid are injected into the tubing. Under the action of the sand-carrying fluid, the gravel enters the first annulus at the bottom of the packer through the filling port and enters the oil layer through the casing. The filled gravel forms a sand-blocking barrier in the oil layer.
[0031] S5, Circulating filling sand control
[0032] Following the previous step, the casing gate on the ground is opened. Under the action of the sand-carrying fluid, the filled gravel enters the first annulus below the packer through the filling hole via the oil pipe. The gravel and part of the sand-carrying fluid then enter the oil layer through the casing, while the other part of the sand-carrying fluid enters the screen pipe, flows through the flushing pipe, and rises under pressure, pushing open the bottom ball and entering the second annulus through the inner circulation port. As it continues to rise, it enters the first annulus above the packer through the outer circulation port and returns to the ground. The filled gravel settles in the first annulus, forming a sand-blocking layer.
[0033] S6, Reverse Circulation Sand Washing
[0034] Circulating fluid is injected into the first annulus above the packer. The circulating fluid enters the second annulus through the inner circulation port of the filling tube and then enters the tubing through the inner circulation port. The steel ball is pushed aside to flush out the excess filling sand above the packer through reverse circulation, preventing excess filling sand from settling and clogging the production channel and sand from jamming the tubing.
[0035] S7, Open the sand-blocking tool
[0036] The oil pipe passage is closed to seal the upper end of the oil pipe, pressurizing the first annulus above the packer. The cup cap moves upward under hydraulic pressure, releasing the cup compressed within it. The released cup opens under its own elasticity, closing the first annulus below the filling port. The specific structure of the cup cap and the principle of its upward movement under hydraulic pressure are existing technology in the field and will not be described in detail.
[0037] S8, Production of stationary tubing
[0038] Closing the casing gate on the surface seals the upper end of the first annulus. Under formation pressure, the crude oil in the oil layer passes through the two sand-blocking layers and the screen pipe, enters the flushing pipe, and rises through the inside of the tubing to the surface for extraction. Alternatively, a pump barrel can be pre-placed in the tubing above the packer for pumping. After the above steps are completed, the pump and sucker rod are lowered to achieve oil production.
[0039] This invention provides an integrated tubing string and method for heavy oil viscosity reduction, filling, and sand control production. It offers the following advantages:
[0040] 1. Compared with existing technologies, this technology enables the production of heavy oil by running a single tubing string without moving the tubing string, achieving viscosity reduction, sand filling and control, and efficient and long-term sand control. It effectively reduces the number of operation steps and improves the efficiency of operation, while achieving energy preservation, viscosity preservation, less pollution from well fluids, and cold damage caused by temperature reduction in heavy oil reservoirs.
[0041] 2. For the first time, the filling tool and screen pipe are coordinated with the filling inner pipe and controlled by ground hydraulic system. This not only meets the needs of large-volume sandstone heavy oil reservoirs for unobstructed injection of viscosity reducers and filling with sand, but also achieves the closure of the lower annulus of the filling port without moving the tubing string, thus meeting the need for long-term production without sand production. Attached Figure Description
[0042] Figure 1 This is a schematic diagram of the structure of the present invention;
[0043] Figure 2 This is a structural schematic diagram of the tubing insertion step of the present invention;
[0044] Figure 3 This is a structural schematic diagram of the throwing, sealing, and opening of the filling port steps of the present invention;
[0045] Figure 4 This is a schematic diagram of the structure of the viscosity reducer step of injecting CO2 and other energy-enhancing agents according to the present invention (the arrows in the figure indicate the direction of liquid or pressure);
[0046] Figure 5 This is a structural schematic diagram of the extrusion filling sand-prevention step of the present invention (arrows in the diagram indicate the direction of liquid or pressure);
[0047] Figure 6 This is a schematic diagram of the cyclic filling sand control structure of the present invention (arrows in the figure indicate the direction of liquid or pressure);
[0048] Figure 7 This is a schematic diagram of the reverse circulation sand flushing step of the present invention (arrows in the figure indicate the direction of liquid or pressure);
[0049] Figure 8This is a structural schematic diagram of the steps for opening the sand-blocking tool according to the present invention (the arrows in the diagram indicate the direction of liquid or pressure);
[0050] Figure 9 This is a schematic diagram of the production steps of the stationary tubing of the present invention (arrows in the diagram indicate the direction of liquid or pressure);
[0051] Figure 10 for Figure 1 Enlarged view of part A in the image.
[0052] In the diagram: 1. Casing; 2. Screen pipe; 3. Oil pipe; 4. Filling inner pipe; 5. Flushing pipe; 6. Packer; 7. Filling sleeve; 8. Steel ball; 9. Sliding sleeve; 10. One-way seal; 101. Leather cup; 102. Leather cup cap; 11. First annulus; 12. Second annulus; 13. Inner circulation port; 14. Outer circulation port; 15. Filling hole; 16. Oil layer. Detailed Implementation
[0053] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0054] In the description of this invention, it should be noted that terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, terms such as "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0055] Furthermore, in the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.
[0056] Please see the appendix Figure 1As shown, the present invention provides a technical solution: an integrated tubing string for heavy oil viscosity reduction, filling, and sand prevention, comprising a casing 1, a screen pipe 2, an oil pipe 3, a filling inner pipe 4, a flushing pipe 5, a packer 6, a filling sleeve 7, a steel ball 8, a sliding sleeve 9, a one-way sealer 10, etc., which are set up by means of sleeve or connection, and the specific setting method is as follows.
[0057] The casing 1 described above is installed inside the oil well and inserted into the oil layer 16, enabling communication with the oil layer. The screen pipe 2 is sealed to the bottom of the tubing 3 via a sealing plug, and has screen holes at its lower part. The tubing 3 is installed inside the casing 1, and has an internal circulation port 13 at its lower part. The filling inner pipe 4 is fitted over the tubing 3, and its two ends are sealed to the tubing 3. A first annulus 11 is formed between the tubing 3, the filling inner pipe 4, the screen pipe 2, and the casing 1. A second annulus 12 is formed between the filling inner pipe 4 and the tubing 3. An external circulation port 14 is provided at the upper end of the filling inner pipe 4, which connects the first annulus 11 and the second annulus 12. The flushing pipe 5 is installed inside the screen pipe 2, and its upper end is sealed to the inner wall of the screen pipe 2. The packer 6 is installed on the filling inner pipe 4 below the external circulation port 14, and can seal the first annulus 11 when open. A filling sleeve 7 is located below the inner circulation port 13 of the tubing 3, and has a filling hole 15 that connects the interior of the tubing 3 and the first annulus 11. A steel ball 8 and a sliding sleeve 9 are located inside the tubing 3. The sliding sleeve 9 is located below the steel ball 8 to prevent it from sinking. The sliding sleeve 9 is sealed to the tubing 3 and can slide inside the tubing 3 to block the filling hole 15. A one-way sealer 10 is fitted onto the filling inner tube 4 below the filling sleeve 7 to seal the first annulus 11 below it. The screen tube 2 and packer 6 are existing technologies, and their specific structures will not be described in detail. Annulus, a common term in the oil production field, refers to the annular space, generally referring to the space around the tubing string suspended in the well. The outer wall of the annulus can be an open hole or a tubing string with a larger outer diameter.
[0058] Furthermore, this embodiment of the invention also includes a bottom ball 13 and a ball seat 14, wherein the ball seat 14 is disposed at the upper end of the flushing pipe 5 and prevents the bottom ball 13 from sinking. Its main function is to seal the upper space and block and limit the flow in the lower space.
[0059] Furthermore, in embodiments of the present invention, see appendix. Figure 1 and attached Figure 10The one-way seal 10 specifically comprises a downward-facing cup 101 and a cup cap 102, with a specific shape being an inverted, trumpet-shaped annular structure. The cup cap 102 is generally made of metal, while the cup 101 is made of elastic material. The cup 101 is in a contracted state within the cup cap 102, and when it detaches from the cup cap 102, it opens due to its own elasticity to seal the first annular cavity 11 below it. The specific structure of the cup cap 102 and its upward movement under hydraulic pressure are as follows: the cup cap 102 communicates with the second annular cavity 12, allowing the pressure of the second annular cavity 12 to be transmitted to the cup cap, causing it to shift. The specific structure and principle of the cup 101 and cup cap 102 are existing technologies in this field, commonly used cup sealers, and therefore will not be described in detail.
[0060] The following is a detailed description of the usage method of the present invention, namely the filling and sand control process steps, in conjunction with the accompanying drawings. The steps are as follows:
[0061] 1. Inserting the tubing into the well
[0062] As attached Figure 2 As shown, after all the above-mentioned tubing components are installed, except for the steel ball 8, the tubing is lowered into the casing 1 through the oil pipe 3, and the screen pipe 2 is aligned with the oil layer. At this time, the sliding sleeve 9 closes the filling hole 15, and the cup 101 contracts under the restriction of the cap of the cup 101, so it does not rub against the inner wall of the casing 1 and is protected.
[0063] 2. Throw the ball, sit down, and open the filling port.
[0064] As attached Figure 3 As shown, the steel ball 8 is placed in the oil pipe 3, and it naturally sinks onto the sliding sleeve 9 under the action of gravity. Pressurization is applied in the oil pipe 3, and the packer 6 unfolds and sets under pressure to achieve the sealing of the first annulus 11. Pressurization continues, and the sliding sleeve 9 and the steel ball 8 descend, exposing the filling port and opening the filling channel.
[0065] 3. Injecting viscosity reducers with energy-enhancing effects such as CO2.
[0066] As attached Figure 4 As shown, a viscosity reducer with an energy-enhancing effect, such as CO2, is injected into the tubing 3. The viscosity reducer enters the first annulus 11 at the bottom of the packer 6 through the filling port and enters the oil layer through the casing 1, thereby achieving energy enhancement and viscosity reduction of heavy oil in the oil layer.
[0067] 4. Extrusion filling for sand control
[0068] As attached Figure 5 As shown, following the previous step, gravel and sand-carrying fluid are injected into the tubing 3. Under the action of the sand-carrying fluid, the gravel enters the first annulus 11 at the bottom of the packer 6 through the filling port and enters the oil layer through the casing 1. The filled gravel forms a sand-blocking barrier in the oil layer.
[0069] 5. Circulating filling for sand control
[0070] As attached Figure 6 As shown, following the previous step, the gate of the casing 1 on the ground is opened. Under the action of the sand-carrying fluid, the filled gravel enters the first annulus 11 at the bottom of the packer 6 through the filling hole 15 via the oil pipe 3. The gravel and part of the sand-carrying fluid then enter the oil layer through the casing 1, while the other part of the sand-carrying fluid enters the screen pipe 2, flows through the flushing pipe 5, and rises under pressure, pushing open the bottom ball 13 and entering the second annulus 12 through the inner circulation port 13. As it continues to rise, it enters the first annulus 11 above the packer 6 through the outer circulation port 14, thus returning to the ground. The filled gravel settles in the first annulus 11, forming a sand-blocking layer.
[0071] 6. Reverse circulation sand flushing
[0072] As attached Figure 7 As shown, circulating fluid is injected into the first annulus 11 above the packer 6. The circulating fluid enters the second annulus 12 through the circulation port of the inner filling pipe 4, and enters the oil pipe 3 through the inner circulation port 13. The steel ball 8 is pushed aside to flush out the excess filling sand above the packer 6 from the oil pipe 3, preventing the excess filling sand from settling and clogging the production channel and the sand from jamming the tubing.
[0073] 7. Open the sand-blocking tool
[0074] As shown in Figure 8, the oil pipe 3 channel is closed to seal the upper end of the oil pipe 3, and the first annulus 11 above the packer 6 is pressurized. The cup cap 102 moves upward under hydraulic action, releasing the cup 101 compressed in the cup cap 102. The released cup 101 opens under its own elastic force, closing the first annulus 11 below the filling port.
[0075] 8. Production of stationary tubing
[0076] As attached Figure 9 As shown, closing the gate valve of casing 1 on the ground seals the upper end of the first annulus 11. Under the action of formation pressure, the crude oil in the oil layer passes through the two sand-blocking layers and screen pipe 2, enters the flushing pipe 5, and ascends to the surface through the inside of the tubing 3 for extraction. Alternatively, a pump barrel can be pre-placed in the tubing 3 above the packer 6 for oil extraction. After the above steps are completed, the pump and sucker rod are lowered to realize oil production.
[0077] Although the above uses many terms describing structures, such as "annular space," "mouth," and "hole," the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of the invention; interpreting them as any additional limitation would contradict the spirit of the invention.
[0078] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. An integrated tubing string for heavy oil viscosity reduction, filling, and sand control, characterized in that, include: The casing is installed inside the oil well and inserted into the oil layer, allowing it to communicate with the oil layer; the screen pipe is sealed to the bottom of the tubing via a sealing plug. An oil pipe is disposed inside the casing, and an internal circulation port is provided at the lower part of the oil pipe; a filling inner pipe is sleeved on the oil pipe, and its two ends are sealed to the oil pipe; a first annulus is formed between the filling inner pipe, the oil pipe, the screen pipe, and the casing, and a second annulus is formed between the filling inner pipe and the oil pipe; an external circulation port is provided at the upper end of the filling inner pipe, and the external circulation port is used to connect the first annulus and the second annulus; a flushing pipe is disposed inside the screen pipe, and its upper end is sealed to the inner wall of the screen pipe; a packer is disposed on the filling inner pipe below the external circulation port; A filling sleeve is disposed below the inner circulation port of the oil pipe, and the filling sleeve has a filling hole that connects the inside of the oil pipe and the first annulus; a steel ball and a sliding sleeve are disposed inside the oil pipe, the sliding sleeve is disposed below the steel ball to prevent it from sinking, the sliding sleeve is sealed to the oil pipe and can slide inside the oil pipe to block the filling hole; a one-way sealer is sleeved on the filling inner tube below the filling sleeve, and the one-way sealer is used to seal the first annulus below it; It also includes a bottom ball and a ball seat, the ball seat being disposed at the upper end of the punch tube and preventing the bottom ball from sinking.
2. The integrated tubing string for heavy oil viscosity reduction, filling, and sand control as described in claim 1, characterized in that, The one-way seal consists of a downward-facing leather cup and a leather cup cap. The leather cup is in a contracted state inside the leather cup cap, and opens to seal the first annular space below it when it is separated from the leather cup cap.
3. The integrated tubing string for heavy oil viscosity reduction, filling, and sand control as described in claim 1, characterized in that, The lower part of the sieve tube is provided with sieve holes.
4. The integrated tubing string for heavy oil viscosity reduction, filling, and sand control as described in claim 1, characterized in that, The packer can seal the first annulus when it is open.
5. A method for heavy oil viscosity reduction, filling, and sand control production using the integrated tubing string for heavy oil viscosity reduction, filling, and sand control as described in any one of claims 1 to 4, characterized in that, Includes the following steps: S1, tubing inserted into the well After all the components of the tubing string are installed, except for the steel ball, the tubing is lowered into the casing through the oil pipe, and the screen tube is aligned with the oil layer. At this time, the sliding sleeve closes the filling hole, and the cup contracts under the restriction of the cup cap, so it does not rub against the inner wall of the casing. S2, Throw the ball, sit down, open the filling port. When the steel ball is placed into the tubing, it naturally sinks onto the sliding sleeve due to gravity. When the tubing is pressurized, the packer unfolds and sets under pressure, achieving the sealing of the first annulus. When the pressure is continued, the sliding sleeve and the steel ball move downward, exposing the filling port and opening the filling channel. S3, a viscosity reducer with CO2 injection for enhanced energy. A viscosity reducer with CO2 energy enhancement effect is injected into the tubing. The viscosity reducer enters the first annulus at the bottom of the packer through the filling port and enters the oil layer through the casing, thereby achieving energy enhancement and viscosity reduction of heavy oil in the oil layer. S4, Extrusion Filling Sand Control Following the previous step, gravel and sand-carrying fluid are injected into the tubing. Under the action of the sand-carrying fluid, the gravel enters the first annulus at the bottom of the packer through the filling port and enters the oil layer through the casing. The filled gravel forms a sand-blocking barrier in the oil layer. S5, Circulating filling sand control Following the previous step, the casing gate on the ground is opened. Under the action of the sand-carrying fluid, the filled gravel enters the first annulus below the packer through the filling hole via the oil pipe. The gravel and part of the sand-carrying fluid then enter the oil layer through the casing, while the other part of the sand-carrying fluid enters the screen pipe. It flows through the flushing pipe and, under pressure, rises and pushes open the bottom ball, entering the second annulus through the inner circulation port. As it continues to rise, it enters the first annulus above the packer through the outer circulation port and returns to the ground. The filled gravel settles in the first annulus, forming a sand-blocking layer. S6, Reverse Circulation Sand Washing Inject circulating fluid into the first annulus above the packer. The circulating fluid enters the second annulus through the inner circulation port of the filling tube and enters the tubing through the inner circulation port. Push the steel ball to flush out the excess filling sand above the packer through reverse circulation, preventing excess filling sand from settling and clogging the production channel and sand from jamming the tubing. S7, Open the sand-blocking tool The oil pipe passage is closed to seal the upper end of the oil pipe, pressurizing the first annulus above the packer. The cup cap moves upward under hydraulic pressure, releasing the cup compressed inside the cup cap. The released cup opens under its own elasticity, closing the first annulus below the filling port. S8, Production of stationary tubing Closing the casing gate on the surface seals the upper end of the first annulus. Under the action of formation pressure, the crude oil in the oil layer passes through two sand-blocking layers and screen pipes, enters the flushing pipe, and then ascends through the inside of the oil pipe to the surface for extraction.