A multi-stage sealing sand prevention completion pipe string and sealing device and method for heavy oil thermal recovery well

Abstract

The application discloses a multi-stage sealing sand prevention completion pipe string and sealing device and method for a heavy oil thermal recovery well, which comprises a hanging device, a quick back-flushing well device, a filling tool, a signal screen pipe section, a main screen pipe section and a check valve which are connected on an oil pipe from top to bottom; the application further comprises an expandable elastic easy-to-handle sealing device and a consolidated sealing and filling flow device which are connected on the oil pipe, the expandable elastic easy-to-handle sealing device is located between the filling tool and the consolidated sealing and filling flow device, and the consolidated sealing and filling flow device is located between the expandable elastic easy-to-handle sealing device and the signal screen pipe section. The application innovates a multi-stage sealing mode, i.e. a hanging device + an expandable elastic easy-to-handle sealing device + a filling belt auxiliary sealing mode, which is reliable in sealing, can effectively prolong the effective period of sand prevention and improve the production cycle of the heavy oil thermal recovery well.

Description

Technical Field

[0001] This invention relates to the field of heavy oil thermal recovery sand control completion technology, specifically a multi-stage sealing sand control completion string and sealing device and method for heavy oil thermal recovery wells. Background Technology

[0002] In Shengli Oilfield, 74.5% of heavy oil reservoirs are developed through thermal recovery, and the primary method for sand control in thermal recovery wells is packing. However, during the development of heavy oil reservoirs through steam injection, the reservoirs are affected by multiple rounds of injection. During the steam injection stage, injected steam can carry sand, loosening the packing layer. During the production stage, formation sand can easily infiltrate the loose packing layer, reducing permeability. This results in a rapid decrease in packing layer permeability and a short effective period for sand control. Furthermore, packers in the completion string can age and fail due to the high temperatures of steam injection, leading to sand control failure and severely impacting the efficient development of heavy oil reservoirs. Therefore, achieving stable, high-density packing layers and establishing effective packing methods to improve sand control effectiveness is of great significance. To address these issues, a multi-stage sealing sand control completion string and method for heavy oil thermal recovery wells are proposed.

[0003] The purpose of this invention is to provide a multi-stage sealing sand control completion string and method for heavy oil thermal recovery wells. Firstly, the method utilizes an integrated structural design for the string, employing a multi-stage sealing design with sealing devices and packing tapes to effectively extend the sand control period and increase the number of production cycles in heavy oil thermal recovery wells. An innovative packing tape-assisted sealing method is adopted, featuring a packing sand-blocking sealing section. This section is equipped with an elastic sand-blocking mesh, which expands and fixes the packing sand during filling. It is also filled with heat-sensitive resin-coated sand, which expands upon heating, making the packing tape denser and more secure while maintaining appropriate permeability. This results in a denser and more secure packing than conventional cyclic packing, and it is less prone to collapse under the suction of production. This effectively addresses the problem of production interruptions caused by packer seal failure. Furthermore, an innovative expandable, elastic, and easily handled sealing device is used, employing a two-stage sealing sand-blocking technology of soft metal and thermal expansion sealing. This further improves the reliability of the seal. It can withstand temperatures up to 350℃ and a sealing pressure differential of 25MPa.

[0004] The following related technologies were found through searching:

[0005] A1, CN1168889C Thermal Recovery Packer;

[0006] A2, CN 1356452A Bimetallic self-sealing thermal recovery packer;

[0007] A3, CN 2357124Y Retractable thermal recovery packer;

[0008] A4, CN 103696728 B A two-stage self-sealing thermal recovery packer;

[0009] B1. "BK361 Series Compensating Thermal Recovery Packer" was published in Petroleum Machinery, Vol. 31, No. 3, 2003;

[0010] B2, "Research and Application of FO-152 Heavy Oil Steam Injection Thermal Recovery Packer" was published in Special Oil and Gas Reservoirs, Vol. 8, 2001.

[0011] Compared to CN1168889C, this patent differs in that, firstly, the present invention aims to provide a multi-stage sealing sand control completion string and method for heavy oil thermal recovery wells. This string, from top to bottom, mainly includes a suspension device, a rapid backwashing device, a filling tool, an expandable elastic easily manageable sealing device, a solidified sealing filling and flow device, a signal screen section, a main screen section, and a check valve. It innovates the multi-stage sealing method: a suspension device + an expandable elastic easily manageable sealing device + a filling tape auxiliary sealing method, ensuring reliable sealing, effectively extending the sand control period, and increasing the number of production cycles for heavy oil thermal recovery wells. In contrast, the thermal recovery packer proposed in patent A1 consists of an upper connector, a bellows, a central pipe, an inner sealing ring for the expansion head, an expansion head, an outer sleeve for the expansion head, an outer sealing ring for the expansion head, a nozzle fixing retainer, a replaceable nozzle, a hydraulic valve, a hydraulic valve sealing ring, a hydraulic valve reset spring, and a lower connector. This invention features a metal forced sealing structure, using hydraulic pressure for setting and releasing. It offers reliable performance, meets temperature requirements of 300-450℃, and effectively prevents casing deformation caused by injecting high-temperature steam during heavy oil extraction. While the packer described in that patent is a metal forced sealing structure, the packer in this patent is a soft metal expansion seal; their structures differ. Furthermore, their applicability is drastically different.

[0012] Compared to CN210152568U, this patent differs in that, firstly, the present invention aims to provide a multi-stage sealing sand control completion string and method for heavy oil thermal recovery wells. This string, from top to bottom, mainly includes a suspension device, a rapid backwashing device, a filling tool, an expandable elastic easily manageable sealing device, a solidified sealing filling and flow device, a signal screen section, a main screen section, and a check valve. It innovates a multi-stage sealing method: a suspension device + an expandable elastic easily manageable sealing device + a filling tape auxiliary sealing method, ensuring reliable sealing, effectively extending the sand control period, and increasing the number of production cycles for heavy oil thermal recovery wells. In contrast, patent A2 proposes a bimetallic self-sealing thermal recovery packer. It consists of a fixed pressure ring, a bimetallic sealing cylinder, a movable pressure ring, and a steel body. This packer utilizes the point of thermal deformation of the bimetallic strip to achieve step-by-step sealing, using the pressure to push the rubber cylinder outward to achieve self-sealing. After injection stops, the bimetallic strip automatically returns to its original position, and the rubber cylinder contracts. The packer described in the comparative patent utilizes the heat-resistant deformation of a metal sheet to achieve automatic expansion and unsealing, which differs from the present invention in terms of technical principle and technical solution.

[0013] Patent 200920240249.4, A3, proposes a retractable thermal recovery packer. This packer consists of an upper variable-thread connector, shear pins, a gland, sealing material, a heat-resistant rubber sleeve, a central body, a spring, a central arm, and a horn. While providing the packer's sealing ring function, the central arm can freely extend and retract within the central body to compensate for the expansion and contraction of the insulation tubing due to temperature changes, as the tubing expands when heated or contracts when cooled. This invention aims to provide a multi-stage sealing sand control completion string and method for heavy oil thermal recovery wells. From top to bottom, the string mainly includes a suspension device, a rapid backwashing device, a filling tool, an expandable elastic easily handled sealing device, a solidified sealing filling and flow device, a signal screen section, a main screen section, and a check valve. It innovates a multi-stage sealing method: a suspension device + an expandable elastic easily handled sealing device + a filling tape auxiliary sealing method, ensuring reliable sealing. The packer described in that patent is a compensating structure, while the packer in this patent is a soft metal expansion seal; the two are structurally very different. Secondly, this patent is mainly used for sand control completion in thermal recovery, while the comparative patent primarily provides a certain compensatory function under sealing conditions; their technical purposes differ. Furthermore, the two differ in their technical principles and solutions.

[0014] Patent application 201010599380.7 (A4) relates to a two-stage self-sealing packer for heavy oil thermal recovery, a downhole tool comprising an upper connector, upper sheath, upper sealing sleeve, upper central tube, expanding solid, lower sheath, inner cone, lower sealing sleeve, combined slider, upper piston, lower piston, cylinder, and lower central tube. The invention aims to provide a multi-stage sealing sand control completion string and method for heavy oil thermal recovery wells. This string, from top to bottom, mainly includes a suspension device, a rapid backwashing device, a filling tool, an expandable elastic easily handled sealing device, a solidified sealing filling and flow device, a signal screen section, a main screen section, and a check valve. The packer structure described in the patent is fundamentally different from this patent. Furthermore, the patent describes automatic thermal setting and unsealing, while this patent uses a soft metal expanding seal; the two are structurally distinct. They also differ significantly in their technical principles and solutions.

[0015] This invention provides a multi-stage sealing sand control completion string and method for heavy oil thermal recovery wells. The string, from top to bottom, mainly includes a suspension device, a rapid backwashing device, a filling tool, an expandable, elastic, and easily manageable sealing device, a solidified sealing filling and flow device, a signal screen section, a main screen section, and a check valve. It innovates the multi-stage sealing method: a suspension device + an expandable, elastic, and easily manageable sealing device + a filling tape auxiliary sealing method, ensuring reliable sealing, effectively extending the sand control period, and increasing the number of production cycles in heavy oil thermal recovery wells. In contrast, the thermal recovery packer proposed in reference B1 is a thermosensitive metal expansion packer, which can seal the annulus during steam injection while also providing compensation. The packer in that article differs from the packer involved in this patent in terms of technical principle and implementation.

[0016] The packer proposed in the paper "Research and Application of FO-152 Heavy Oil Steam Injection Thermal Recovery Packer" is a line seal made of shape memory alloy and has dynamic sealing properties. This invention provides a multi-stage sealing sand control completion string and method for heavy oil thermal recovery wells. From top to bottom, the string mainly includes a suspension device, a rapid backwashing device, a filling tool, an expandable elastic easily handled sealing device, a solidified sealing filling and flow device, a signal screen section, a main screen section, and a check valve. It innovates the multi-stage sealing method: suspension device + expandable elastic easily handled sealing device + filling tape auxiliary sealing method, ensuring reliable sealing, effectively extending the sand control period, and increasing the number of production cycles in heavy oil thermal recovery wells. The packer in that paper is made of shape memory alloy and has dynamic sealing properties. This is fundamentally different from the technical solution of this patent. Furthermore, the two differ significantly in structure. In addition, the packer in that paper differs fundamentally from this patent in terms of invention purpose, technical principle, and process string. Summary of the Invention

[0017] To address the aforementioned deficiencies in existing technologies, the purpose of this invention is to provide a multi-stage sealing sand control completion string, sealing device, and method for heavy oil thermal recovery wells. It innovates a multi-stage sealing method, namely: a suspension device + an expandable, elastic, and easily manageable sealing device + a filling tape auxiliary sealing method. This ensures reliable sealing, effectively extends the sand control period, and increases the number of production cycles in heavy oil thermal recovery wells.

[0018] To achieve the above objectives, the present invention adopts the following technical solution:

[0019] A multi-stage sealing and sand-control completion string for heavy oil thermal recovery wells includes a suspension device, a rapid backwashing device, a filling tool, a signal screen section, a main screen section, and a check valve connected from top to bottom to the tubing.

[0020] It also includes an expandable elastic easily handled sealing device and a solidified seal filling and flow device connected to the oil pipe. The expandable elastic easily handled sealing device is located between the filling tool and the solidified seal filling and flow device, and the solidified seal filling and flow device is located between the expandable elastic easily handled sealing device and the signal screen pipe section.

[0021] The expandable, elastic, and easily handled sealing device includes, from top to bottom, an upper sealing device connector, an expandable sealing element, and a lower sealing device connector.

[0022] The expandable seal comprises, from the inside out, a support, an expandable pre-filled layer, and a corrugated soft metal layer.

[0023] The support component includes a support base tube and support ribs, with the support ribs welded to the support base tube.

[0024] The supporting ribs are multiple and spirally distributed on the supporting base tube.

[0025] The upper end of the consolidation sealing filling and flow device is threadedly connected to the oil pipe, and the lower end is threadedly connected to the oil pipe; the consolidation sealing filling and flow device is equipped with a one-way flow valve that allows flow from the outside of the oil pipe to the inside of the oil pipe.

[0026] The signal screen tube section, the main screen tube section, and the sand-blocking layer formed by the circulating filling outside the signal screen tube section and the main screen tube section together constitute the filling sand-blocking sealing section.

[0027] The solidified sealing filling and flow device and the sand-blocking layer deposited around the solidified sealing filling and flow device together constitute the solidified sealing filling and flow sealing section.

[0028] The consolidation seal filling flow sealing section and the filling sand-blocking sealing section together constitute the filling strip.

[0029] To achieve the above objectives, the present invention adopts the following technical solution:

[0030] A method for using a multi-stage sealing sand-control completion string in a heavy oil thermal recovery well includes the following steps:

[0031] During filling, the filling slurry is pumped into the tubing and enters the annulus between the tubing and the open hole wall through the filling port of the filling tool. The slurry carrying sand flows through the one-way valve at the bottom from the tubing through the clamping channel of the filling tool to the annulus between the tubing and the casing and returns to the surface.

[0032] As the filling sand is gradually filled into the signal screen pipe section, the pressure gradually increases. When the pressure reaches the set value, the one-way valve of the solidification and sealing filling flow device opens under the pressure. The sand-carrying fluid can enter the oil pipe through the solidification and sealing filling flow device and then return, while the filling sand is deposited around the solidification and sealing filling flow device. When the pressure reaches the design value, the cycle filling ends.

[0033] When steam injection is performed during heavy oil thermal recovery, the heat-sensitive resin-coated sand in the packing strip will further expand under the action of heat, making the packing strip more compact and firm while retaining permeability.

[0034] It also includes the following steps:

[0035] Before filling, the designed tubing string is lowered into the well at the predetermined position;

[0036] Throw the ball, pressurize the oil pipe, and set the suspension device;

[0037] Continue applying pressure to open the filling port of the filling tool.

[0038] It also includes the following steps:

[0039] After filling is completed, a rapid backwashing process is performed.

[0040] Release the suspension device and remove the release column.

[0041] To achieve the above objectives, the present invention adopts the following technical solution:

[0042] An expandable, elastic, and easily handled sealing device for multi-stage sealing and sand control completion tubing in heavy oil thermal recovery wells includes an upper sealing device connector, an expandable sealing element, and a lower sealing device connector connected sequentially from top to bottom; the expandable sealing element includes, from the inside out, a support element, an expandable pre-filling layer, and a corrugated soft metal layer.

[0043] The support includes a support base tube and support ribs, the support ribs being welded to the support base tube; there are multiple support ribs, which are evenly distributed spirally on the support base tube.

[0044] Compared with the prior art, the present invention has the following advantages:

[0045] (1) Through the overall structural design, this tubing string can achieve sand control completion of single-layer or multi-layer sections in heavy oil thermal recovery wells. It innovates a multi-level sealing method, namely: suspension device + expandable elastic easy-to-handle sealing device + filling tape auxiliary sealing method. The sealing is reliable, which can effectively extend the sand control period and increase the production cycle of heavy oil thermal recovery wells.

[0046] (2) An innovative filling-assisted sealing method was developed, including an expandable filling and sand-blocking sealing section formed by cyclic filling outside the signal screen pipe and main screen pipe sections. Thermosensitive resin-coated sand is circulated and filled outside the signal screen pipe and main screen pipe sections. This sand expands when heated, making the filling strip more compact and secure while maintaining a suitable permeability. It is less prone to collapse under repeated flushing and suction during throughput production. This effectively solves the problem of production interruption caused by the easy failure of simple packer seals due to thermal recovery.

[0047] (3) An innovative expandable, elastic, and easily handled sealing device was developed, employing soft metal and heat-sensitive sealing technology. Structurally, it features an innovative combination of four spirally distributed metal support ribs and internal thermally expanding resin, providing expansion support under thermal action. During thermal extraction, the internal thermally expanding resin expands, causing the four spirally distributed metal support ribs to expand and adhere tightly to the open hole wall, further improving the reliability of the seal. It can withstand temperatures up to 350℃ and has a sealing pressure differential of 25MPa. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the structure of a multi-stage sealing sand-control completion string for heavy oil thermal recovery wells according to the present invention;

[0049] Figure 2 This is a schematic diagram of the expandable, elastic, and easily handled sealing device of the present invention;

[0050] Figure 3 for Figure 2 Cross-sectional view;

[0051] Figure 4 , Figure 5 This is a schematic diagram of the cyclic filling process;

[0052] Figure 6 This is a schematic diagram of a rapid backwashing well process.

[0053] In the diagram: Casing 1, Tubing 2, Open Hole 3, Suspension Device 4, Rapid Backwashing Device 5, Packing Tool 6, Expandable Elastic Easy-to-Manage Sealing Device 7, Consolidated Sealing Packing Flow Device 8, Signal Screen Section 9, Main Screen Section 10, One-Way Valve 11, Consolidated Sealing Packing Flow Sealing Section 12, Packing Sand-Blocking Sealing Section 13, One-Way Flow Valve 8-1.

[0054] The sealing device includes an upper connector 7-1, an expandable seal 7-2, and a lower connector 7-3. It also includes a support component 7-2-1, an expandable pre-filled layer 7-2-2, a corrugated soft metal layer 7-2-3, a support base tube 7-2-1-1, and a support rib 7-2-1-2. Detailed Implementation

[0055] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] Example 1:

[0057] like Figures 1 to 6As shown, the present invention provides a multi-stage sealing sand control completion string for heavy oil thermal recovery wells. The string mainly includes, from top to bottom, a suspension device 4, a rapid backwashing device 5, a filling tool 6, an expandable elastic and easily handled sealing device 7, a consolidation sealing filling and flow device 8, a signal screen section 9, a main screen section 10, and a check valve 11.

[0058] The suspension device 4, the rapid backwashing well device 5, the filling tool 6, the signal screen pipe section 9, the main screen pipe section 10, and the one-way valve 11 are existing technologies.

[0059] The expandable, elastic, and easily manageable sealing device 7 includes an upper connector 7-1, an expandable seal 7-2, and a lower connector 7-3. The upper end of the expandable, elastic, and easily manageable sealing device 7 is threadedly connected to the tubing via the upper connector 7-1, and the lower end is threadedly connected to the tubing via the lower connector 7-3. Multiple expandable, elastic, and easily manageable sealing devices 7 can be installed according to the length of the sand-control well section.

[0060] The expandable seal 7-2 comprises, from the inside out, a support 7-2-1, an expandable pre-filled layer 7-2-2, and a corrugated soft metal layer 7-2-3. The support 7-2-1 includes a support base tube 7-2-1-1 and support ribs 7-2-1-2. The support ribs 7-2-1-2 are welded to the support base tube 7-2-1-1. There are multiple support ribs 7-2-1-2, spirally and evenly distributed on the support base tube 7-2-1-1.

[0061] The expandable prefill layer 7-2-2 expands upon heating during downhole steam injection, and its thickness can be designed according to the open hole size. The expandable prefill layer 7-2-2 fills the gaps between the support ribs 7-2-1-2 of the support member 7-2-1, and its internal filling material is heat-sensitive resin. Under the thermal effect of steam injection, the expandable prefill layer 7-2-2 expands, causing the outer corrugated soft metal layer 7-2-3 to expand and adhere to the open hole wall 3, forming a seal. The expandable prefill layer 7-2-2 is tightly wrapped around the support member 7-2-1 by the corrugated soft metal layer 72-3.

[0062] The corrugated soft metal layer 7-2-3 is made of soft metal and is tightly wrapped around the outside of the expandable pre-filled layer 7-2-2 for fixation. The outer surface of the corrugated soft metal layer 7-2-3 has a corrugated structure, which can better conform to the open hole well wall and play a good sealing role.

[0063] The consolidation sealing filling and circulation device 8 is threadedly connected to the oil pipe at both its upper and lower ends. It is equipped with a one-way flow valve 8-1 that allows flow from the outside to the inside of the oil pipe. The opening pressure of this one-way flow valve 8-1 is approximately 8 MPa. This one-way flow valve 8-1 opens when the pressure reaches 8 MPa during circulating filling to the signal screen pipe, allowing the sand-carrying fluid to pass through. The filling sand carried by the sand-carrying fluid (the heat-sensitive resin-coated sand can be followed by the filling sand at the end of the circulating filling process) settles on the outside of the consolidation sealing filling and circulation device 8, forming a good sand-blocking layer and providing a good sealing effect, i.e., the consolidation sealing filling and circulation sealing section 12. This effectively compensates for the failure of the simple suspension device 4 seal during multiple rounds of thermal recovery.

[0064] The filling and sand-blocking sealing section 13 comprises a sand-blocking layer formed by external circulating filling of the signal screen pipe section 9 and the main screen pipe section 10. The internal filling material of the filling and sand-blocking sealing section 13 is thermosensitive resin-coated sand, the particle size, dosage, and discharge rate of which can be designed according to reservoir characteristics. The thermosensitive resin-coated sand has the characteristic of expanding when heated, which makes the filling and sand-blocking sealing section 13 more compact and firm while maintaining a suitable permeability, making it less prone to collapse under the repeated flushing and suction action of thermal recovery production. This effectively compensates for the insufficient sealing problem when using a simple suspended device for thermal recovery.

[0065] This tubing string, through its overall structural design, enables single- or multi-stage sand control completion in heavy oil thermal recovery wells. It also features an innovative multi-stage sealing method: a suspension device + an expandable, elastic, and easily handled sealing device + a filling tape auxiliary sealing method. This ensures reliable sealing, effectively extends the sand control period, and increases the number of production cycles in heavy oil thermal recovery wells.

[0066] An innovative filling tape-assisted sealing method was developed, comprising an expandable filling sand-blocking sealing section formed by cyclic filling outside the signal screen tube and main screen tube sections. Thermosensitive resin-coated sand is circulated and filled outside the signal screen tube and main screen tube sections. Its thermal expansion characteristic makes the filling tape denser and stronger while maintaining appropriate permeability, preventing collapse under repeated flushing and suction during throughput production. This effectively solves the problem of production interruption caused by the easy failure of simple packer seals due to thermal recovery.

[0067] An innovative expandable, elastic, and easily handled sealing device was developed, employing soft metal and heat-sensitive sealing technology. Structurally, it features a novel combination of four spirally distributed metal support ribs and internal thermally expanding resin. This design provides expansion support under thermal conditions. During thermal extraction, the internal thermally expanding resin expands, causing the four spirally distributed metal support ribs to expand and adhere tightly to the open-hole wall, further improving sealing reliability. It can withstand temperatures up to 350℃ and a sealing pressure differential of 25MPa.

[0068] Example 2:

[0069] A multi-stage sealing and sand control completion method for heavy oil thermal recovery wells includes the following steps (taking one sand control section as an example):

[0070] Step 1: Lower the designed tubing string into the predetermined position inside the well.

[0071] Step 2: Throw the ball, pressurize from the oil pipe, and set the suspension device 4.

[0072] Step 3: Continue pressurizing and open the filling port of filling tool 6.

[0073] Step 4: Filling is carried out according to the designed displacement and filling sand volume. During filling, filling sand slurry is pumped from tubing 2 (for circulating filling, proppant can be made of ceramsite or tail-end heat-sensitive resin coated sand), entering the annulus between tubing 1 and open hole wall 3 through the filling port of filling tool 6. The sand-carrying fluid flows through the one-way valve 11 at the bottom from tubing 2 through the clamping channel of filling tool 6 to the annulus between tubing 2 and casing 1 and returns to the surface. As the filling sand gradually fills to the signal screen section 9, the pressure gradually increases. When the pressure reaches 8MPa, the one-way valve 8-1 of the solidified sealing filling flow device 8 opens under pressure, allowing the sand-carrying fluid to enter tubing 2 and return through the solidified sealing filling flow device 8, while the filling sand settles around the solidified sealing filling flow device 8. Circulating filling ends when the pressure reaches 25MPa or the design value. When steam injection is performed during heavy oil thermal recovery, the heat-sensitive resin-coated sand will expand further under the action of heat, making the filling strip more compact and firm while retaining permeability.

[0074] Step 5: After filling is completed, perform rapid backwashing of the well.

[0075] Step 6: Release the suspension device 4 and remove the release column.

[0076] Example 3:

[0077] The expandable, elastic, and easily manageable sealing device 7 includes an upper connector 7-1, an expandable seal 7-2, and a lower connector 7-3. The upper end of the expandable, elastic, and easily manageable sealing device 7 is threadedly connected to the tubing via the upper connector 7-1, and the lower end is threadedly connected to the tubing via the lower connector 7-3. Multiple expandable, elastic, and easily manageable sealing devices 7 can be installed according to the length of the sand-control well section.

[0078] The expandable seal 7-2 comprises, from the inside out, a support 7-2-1, an expandable pre-filled layer 7-2-2, and a corrugated soft metal layer 7-2-3. The support 7-2-1 includes a support base tube 7-2-1-1 and support ribs 7-2-1-2. The support ribs 7-2-1-2 are welded to the support base tube 7-2-1-1. There are multiple support ribs 7-2-1-2, spirally and evenly distributed on the support base tube 7-2-1-1.

[0079] The expandable prefill layer 7-2-2 expands upon heating during downhole steam injection, and its thickness can be designed according to the open hole size. The expandable prefill layer 7-2-2 fills the gaps between the support ribs 7-2-1-2 of the support member 7-2-1, and its internal filling material is heat-sensitive resin. Under the thermal effect of steam injection, the expandable prefill layer 7-2-2 expands, causing the outer corrugated soft metal layer 7-2-3 to expand and adhere to the open hole wall 3, forming a seal. The expandable prefill layer 7-2-2 is tightly wrapped around the support member 7-2-1 by the corrugated soft metal layer 72-3.

[0080] The corrugated soft metal layer 7-2-3 is made of soft metal and is tightly wrapped around the outside of the expandable pre-filled layer 7-2-2 for fixation. The outer surface of the corrugated soft metal layer 7-2-3 has a corrugated structure, which can better conform to the open hole well wall and play a good sealing role.

[0081] All components not discussed in detail in this application, as well as the connection methods of these components, are well-known technologies in this field. They can be directly applied and will not be elaborated further.

[0082] In this invention, the term "multiple" refers to two or more unless otherwise explicitly defined. The terms "install," "connect," "link," and "fix" should be interpreted broadly. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "link" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0083] In the description of this invention, it should be understood that the terms "upper," "lower," "left," "right," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or unit 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 this invention.

[0084] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0085] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A multi-stage sealing sand control completion string for heavy oil thermal recovery wells, comprising a suspension device, a rapid backwashing device, a filling tool, a signal screen section, a main screen section, and a check valve connected from top to bottom to the tubing; Its features are, It also includes an expandable elastic easily handleable sealing device and a solidified seal filling and flow device connected to the oil pipe. The expandable elastic easily handleable sealing device is located between the filling tool and the solidified seal filling and flow device, and the solidified seal filling and flow device is located between the expandable elastic easily handleable sealing device and the signal screen pipe section. The expandable, elastic, and easily handled sealing device includes, from top to bottom, an upper sealing device connector, an expandable sealing element, and a lower sealing device connector; The expandable seal comprises, from the inside out, a support, an expandable pre-filled layer, and a corrugated soft metal layer; The upper end of the solidified sealing filling and flow device is threadedly connected to the oil pipe, and the lower end is threadedly connected to the oil pipe; the solidified sealing filling and flow device is equipped with a one-way flow valve that allows flow from the outside of the oil pipe to the inside of the oil pipe. When the filling fluid is circulated to the signal screen tube, when the pressure reaches the opening pressure, the one-way flow valve opens, allowing the sand-carrying fluid to pass through. The filling sand carried by the sand-carrying fluid settles on the outside of the consolidation and sealing filling flow device, forming a good sand-blocking layer.

2. The multi-stage sealing sand-control completion string for heavy oil thermal recovery wells according to claim 1, characterized in that, The support component includes a support base tube and support ribs, with the support ribs welded to the support base tube.

3. The multi-stage sealing sand-control completion string for heavy oil thermal recovery wells according to claim 2, characterized in that, The supporting ribs are multiple and spirally distributed on the supporting base tube.

4. The multi-stage sealing sand-control completion string for heavy oil thermal recovery wells according to claim 3, characterized in that, The signal screen tube section, the main screen tube section, and the sand-blocking layer formed by the circulating filling outside the signal screen tube section and the main screen tube section together constitute the filling sand-blocking sealing section. The solidified sealing filling and flow device and the sand-blocking layer deposited around the solidified sealing filling and flow device together constitute the solidified sealing filling and flow sealing section. The consolidation seal filling flow sealing section and the filling sand-blocking sealing section together constitute the filling strip.

5. A method for using a multi-stage sealing sand-control completion string for heavy oil thermal recovery wells, characterized in that, Using the multi-stage sealing and sand-control completion string for heavy oil thermal recovery wells as described in claim 4 includes the following steps: During filling, the filling slurry is pumped into the tubing and enters the annulus between the tubing and the open hole wall through the filling port of the filling tool. The slurry carrying sand flows through the one-way valve at the bottom from the tubing through the clamping channel of the filling tool to the annulus between the tubing and the casing and returns to the surface. As the filling sand is gradually filled into the signal screen pipe section, the pressure gradually increases. When the pressure reaches the set value, the one-way valve of the solidification and sealing filling flow device opens under the pressure. The sand-carrying fluid can enter the oil pipe through the solidification and sealing filling flow device and then return, while the filling sand is deposited around the solidification and sealing filling flow device. When the pressure reaches the design value, the cycle filling ends. When steam injection is performed during heavy oil thermal recovery, the heat-sensitive resin-coated sand in the packing strip will further expand under the action of heat, making the packing strip more compact and firm while retaining permeability.

6. The method of using a multi-stage sealing sand-control completion string for heavy oil thermal recovery wells according to claim 5, characterized in that, It also includes the following steps: Before filling, the designed tubing string is lowered into the well at the predetermined position; Throw the ball, pressurize it from the oil pipe, and set the suspension device; Continue applying pressure to open the filling port of the filling tool.

7. The method of using a multi-stage sealing sand-control completion string for heavy oil thermal recovery wells according to claim 6, characterized in that, It also includes the following steps: After filling is completed, a rapid backwashing process is performed. Release the suspension device and remove the release column.

8. The special expandable, elastic, and easily handled sealing device for a multi-stage sealing sand-proof completion string for heavy oil thermal recovery wells as described in claim 1, characterized in that, It includes, from top to bottom, an upper connector of the sealing device, an expandable seal, and a lower connector of the sealing device; the expandable seal includes, from the inside out, a support, an expandable pre-filled layer, and a corrugated soft metal layer.

9. The dedicated expandable, elastic, and easily handled sealing device according to claim 8, characterized in that, The support includes a support base tube and support ribs, the support ribs being welded to the support base tube; there are multiple support ribs, which are evenly distributed spirally on the support base tube.

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