Sand control packer

Abstract

This invention relates to the field of oil extraction technology, specifically to a sand-proof packer. It includes an upper rubber sleeve seat, a lower rubber sleeve seat, a slip assembly, and several rubber sleeve bodies. A spacer mechanism is provided between adjacent rubber sleeve bodies to axially separate the two sections of the rubber sleeve body. The spacer mechanism includes an upper metal spacer fixed to the end of the upper rubber sleeve body and a lower metal spacer fixed to the end of the lower rubber sleeve body. A fluid replenishment mechanism is located between the upper and lower metal spacers. During setting, the upper and lower metal spacers move towards each other, driving the fluid replenishment mechanism to spray lubricant into the stagnation zone, forcing accumulated sand and gravel to diffuse into the mixed solution. Simultaneously, the fluid replenishment mechanism, through the negative pressure effect formed at the pumping channel, further attracts sand and gravel from the mixed solution, inhibiting secondary accumulation of sand and gravel in the stagnation zone, thereby preventing the rubber sleeve body from being squeezed and scratched by sand and gravel during expansion, thus improving the service life of the rubber sleeve body.

Description

Technical Field

[0001] This invention relates to the field of oil extraction technology, and more specifically, to a sand packer. Background Technology

[0002] In downhole operations involving layered development and fracturing of loose sandstone oil and gas reservoirs, it is necessary to use multiple rubber sleeves in conjunction with a spacer ring mechanism to achieve sealing and isolation of the annulus of the casing and tubing, thus isolating different oil and gas layers from each other.

[0003] In conventional sand packers, adjacent rubber sleeves are axially separated and limited by metal spacers. An annular gap is formed between the metal spacers and the inner wall of the casing. Formation fine sand and fracturing proppant in the downhole sand-carrying fluid are easily deposited in this gap, forming a sand and gravel retention zone.

[0004] When the segmented wellbore is in a vertical position, gravel accumulates under gravity. During the setting operation, the upper rubber sleeve seat presses the rubber sleeve axially downwards, forcing it to expand radially outwards to conform to the inner wall of the casing and tubing for sealing. When gravel accumulates in the annular gap between the end of the rubber sleeve and the metal spacer, the rubber sleeve, under pressure, directly squeezes the retained gravel. Hard, sharp sand particles can easily cut into and scratch the rubber sleeve end face, causing damage and tearing defects on the sealing surface, reducing the isolation and sealing effect against downhole gravel. Furthermore, during the unsealing operation, the rubber sleeve retracts axially with the tubing string and slides relative to the inner wall of the casing and tubing. Retained gravel in the gap will embed between the friction pairs, causing abrasive wear. This increases the axial pull-out load required for the unsealing operation; moreover, the gravel continuously cuts the outer wall of the rubber sleeve, repeatedly causing scratches and wear, shortening the service life of the rubber sleeve. Summary of the Invention

[0005] This invention provides a sand-proof packer, which, by means of the upper and lower metal spacers moving toward each other during setting, drives the fluid replenishment mechanism to spray lubricant into the retention area, thereby solving the problem mentioned in the background art, namely: sand particles scratching the end face of the rubber tube. To achieve the above objectives, the sand packer includes an upper rubber sleeve seat, a lower rubber sleeve seat, a slip assembly, and a plurality of rubber sleeve bodies disposed between the upper and lower rubber sleeve seats. The rubber sleeve bodies are pressed against the inner wall of the casing. A spacer ring mechanism is provided between adjacent rubber sleeve bodies to axially separate the two rubber sleeve bodies. The spacer ring mechanism includes an upper metal spacer ring fixed to the end of the upper rubber sleeve body and a lower metal spacer ring fixed to the end of the lower rubber sleeve body. A fluid replenishment mechanism is provided between the upper and lower metal spacer rings, and the lower metal spacer ring and the inner wall of the casing form a sand and gravel retention area for accommodating downhole sand and gravel. When the upper rubber sleeve seat moves axially downward to perform the setting and sealing operation, the upper metal spacer ring and the lower metal spacer ring undergo a pressing motion towards each other, which drives the replenishing mechanism to spray and supply its internal lubricant to the stagnation area to disperse the sand and gravel in the stagnation area. At the same time, the replenishing mechanism guides the dispersed sand and gravel to the outer circumference of the lower metal spacer ring. During the unsealing operation, a negative pressure suction effect is formed in the fluid replenishment mechanism, which forces the lubricant to be directionally transported to the retention area. A lubricating oil film is formed at the position where the rubber sleeve body and the oil sleeve tube have axial relative sliding friction, so as to achieve lubrication compensation for the axial friction of the rubber sleeve body.

[0006] An outer ring is coaxially sleeved on the outside of the upper metal spacer ring and the lower metal spacer ring. Inner retaining rings are fixed at both the upper and lower ends of the outer ring. Inner retaining rings are fixed on the outside of both the upper metal spacer ring and the lower metal spacer ring. Both the upper and lower metal spacers have outer retaining rings formed axially on their outer peripheral walls. The inner retaining ring and the outer retaining ring are slidably disposed together, and the outer retaining ring provides radial constraint to the inner retaining ring.

[0007] The upper metal spacer ring, lower metal spacer ring, outer ring, and inner tube together form a movable cavity. The lower metal spacer ring has a fluid delivery channel that connects the movable cavity and the stagnation area. When the upper metal spacer ring and the lower metal spacer ring move axially towards each other, the fluid delivery channel is responsible for supplying lubricating fluid to the stagnation area.

[0008] The fluid replenishment mechanism includes a shaft cylinder fixedly mounted on an outer ring and a piston rod slidably mounted in a fluid collection chamber inside the shaft cylinder. The outer ring has a discharge channel connecting the movable chamber and the fluid collection chamber, and a suction channel connecting the fluid collection chamber and the stagnation area. During the setting operation, the piston rod is used to discharge lubricating fluid into the movable chamber through radial movement, forcing a negative pressure suction to be formed in the suction channel.

[0009] The fluid replenishment mechanism also includes a power block disposed in the movable cavity. The power block is connected to the piston rod via a connecting rod, and a compression spring is elastically connected between the piston rod and the outer ring.

[0010] The shaft cylinder is also provided with a drainage channel. Both the drainage channel and the extraction channel are equipped with one-way check valves. The check valve located in the extraction channel is used to transport external solution into the shaft cylinder, and the check valve located in the drainage channel is used to discharge the solution inside the shaft cylinder outward.

[0011] An inner slope groove is formed on the lower metal spacer ring to accommodate the dispersed gravel. The cross-sectional area of ​​the inner slope groove gradually decreases from the retention area to the outer circumference of the lower metal spacer ring.

[0012] Several anti-backflow inner channels are provided on the inner wall of the inner slope channel to prevent the sand and gravel from flowing back into the retention area. The anti-backflow inner channels are opened towards the outer peripheral surface of the lower metal spacer ring.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. In this sand-proof packer, the upper and lower metal spacers move towards each other during setting, driving the replenishing mechanism to spray lubricant into the stagnation zone, forcing the accumulated sand and gravel to diffuse into the mixed solution. At the same time, the replenishing mechanism further attracts the sand and gravel in the mixed solution through the negative pressure effect formed at the liquid extraction channel, inhibiting the secondary accumulation of sand and gravel in the stagnation zone, thereby preventing the rubber sleeve body from being squeezed and scratched by sand and gravel when it expands, thus improving the service life of the rubber sleeve body.

[0014] 2. In this sand-proof packer, during the unsealing stage, the liquid replenishment mechanism draws the mixed solution at the liquid delivery channel, continuously guiding the lubricant in the mixed solution to the stagnation area, forming a continuous lubricating oil film on the friction surface of the rubber sleeve body and the oil casing during the retraction process, reducing the wear of the rubber sleeve body and the unsealing pull-out resistance. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the sealing state of the present invention; Figure 3 This is a schematic diagram of the exploded structure of the spacer ring mechanism and the rubber tube body of the present invention; Figure 4 This is a schematic diagram of the cross-sectional structure of the inner tube, upper metal spacer ring, lower metal spacer ring and shaft cylinder of the present invention. Figure 5 For the present invention Figure 4 Enlarged structural diagram at point A in the diagram; Figure 6 This is a schematic diagram of the cross-sectional structure of the shaft cylinder and outer ring of the present invention; Figure 7 This is a schematic diagram of the exploded structure of the upper metal spacer ring, outer ring, and lower metal spacer ring of the present invention; Figure 8 This is a schematic diagram of the initial state of the piston rod of the present invention; Figure 9 This is a schematic diagram of the piston rod extruding lubricating fluid according to the present invention.

[0016] The meanings of the labels in the diagram are as follows: 100. Upper rubber sleeve seat; 101. Rubber sleeve body; 102. Lower rubber sleeve seat; 103. Slip assembly; 104. Oil sleeve; 105. Inner tube; 110. Spacer ring mechanism; 111. Upper metal spacer ring; 112. Lower metal spacer ring; 113. Outer ring; 114. Movable cavity; 115. Infusion channel; 116. Outer retaining ring; 117. Inner retaining ring; 120. Inner slope trough; 130. Shaft; 131. Piston rod; 132. Power block; 133. Liquid suction channel; 134. Liquid discharge channel; 135. Liquid release channel; 136. Compression spring. Detailed Implementation

[0017] The technical solutions of this invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0018] Therefore, in view of the above-mentioned problems, the present invention provides a sand-proof packer, with reference to... Figure 1 As shown, it includes an upper glue cartridge holder 100, a lower glue cartridge holder 102, a clamping assembly 103, and a plurality of glue cartridge bodies 101 disposed between the upper glue cartridge holder 100 and the lower glue cartridge holder 102, for reference. Figure 2 As shown, during setting, the rubber sleeve body 101 expands and presses against the inner wall of the oil casing 104. The W region shown on the outer side of the oil casing 104 profile is a geological profile. The specific setting principle of this equipment is as follows: Step 1: When the equipment is lowered to the designed depth of the target oil and gas layer, high-pressure setting working fluid is pumped from the ground into the oil pipe. The high-pressure liquid drives the upper rubber sleeve seat 100 to generate a downward axial thrust. The second step is that the upper rubber sleeve seat 100 moves downward axially under the action of hydraulic pressure, driving the upper cone to move downward synchronously; the conical surfaces of the upper and lower cones squeeze the upper and lower sets of slip assemblies 103, the slip assemblies 103 are stretched outward radially, and are locked and anchored on the inner wall of the oil casing 104, so as to realize the axial limiting and fixing of the packer as a whole. In the third step, after the locking assembly 103 is anchored, the upper rubber sleeve seat 100 continues to descend. Under the bidirectional axial compression of the upper rubber sleeve seat 100 and the lower rubber sleeve seat 102, multiple rubber sleeve bodies 101 are axially compressed and undergo radial outward expansion deformation. The outer wall of the rubber sleeve body 101 is tightly pressed against the inner wall of the oil casing 104 to achieve sealing and isolation, blocking the flow of interlayer fluid and gravel.

[0019] Next, refer to Figure 3 , Figure 4A spacer mechanism 110 is provided between adjacent rubber sleeve bodies 101 to axially separate the two rubber sleeve bodies 101. The spacer mechanism 110 includes an upper metal spacer 111 fixed to the end of the upper rubber sleeve body 101 and a lower metal spacer 112 fixed to the end of the lower rubber sleeve body 101. A fluid replenishment mechanism is provided between the upper metal spacer 111 and the lower metal spacer 112, and the lower metal spacer 112 and the inner wall of the oil casing 104 enclose a gravel retention area for accommodating downhole gravel. When the upper rubber sleeve seat 100 moves axially downward to perform the setting and sealing operation, due to Figure 2 At this time, the locking assembly 103 is in a locked and anchored state, and the downward movement of the lower rubber sleeve seat 102 is blocked. Therefore, the upper metal spacer ring 111 and the lower metal spacer ring 112 undergo a pressing motion towards each other, driving the fluid replenishment mechanism to spray its internal lubricant to the stagnant area to disperse the sand and gravel in the stagnant area. At the same time, the fluid replenishment mechanism guides the dispersed sand and gravel to the outer circumference of the lower metal spacer ring 112 to reduce the sand and gravel content in the stagnant area and prevent sand and gravel from getting stuck in the assembly gap between the rubber sleeve body 101 and the lower metal spacer ring 112. During the unsealing operation, a negative pressure suction effect is formed in the fluid replenishment mechanism, which forces the lubricant to be directionally delivered to the stagnant area. A lubricating oil film is formed at the position where the rubber sleeve body 101 and the oil sleeve 104 have axial relative sliding friction, so as to achieve lubrication compensation for the axial friction of the rubber sleeve body 101, reduce abrasive wear and unsealing friction resistance.

[0020] based on Figure 3 Based on this, and then combined Figure 5 As shown, an outer ring 113 is coaxially sleeved on the outer sides of the upper metal spacer 111 and the lower metal spacer 112. Inner retaining rings 117 are fixed at both the upper and lower ends of the outer ring 113. Inner retaining rings 117 are fixed on the outer sides of both the upper metal spacer 111 and the lower metal spacer 112. Outer retaining rings 116 are formed axially on the outer peripheral walls of both the upper metal spacer 111 and the lower metal spacer 112. The inner retaining rings 117 and the outer retaining rings 116 are slidably arranged. The outer retaining rings 116 form a radial constraint on the inner retaining rings 117, preventing the outer ring 113 from axially slipping off relative to the upper metal spacer 111 and the lower metal spacer 112. Thus, during the setting operation, the upper metal spacer 111 moves downward and the lower metal spacer 112 moves upward relative to each other. The inner retaining ring 117 can slide smoothly axially within the outer retaining ring 116 without restricting the opposing stroke of the metal spacers, and the overall assembly stability can always be maintained.

[0021] Return to Figure 4As shown, the upper metal spacer ring 111, the lower metal spacer ring 112, the outer ring 113, and the inner tube 105 together form a movable cavity 114. The lower metal spacer ring 112 has a fluid delivery channel 115 that connects the movable cavity 114 and the stagnation area. When the upper metal spacer ring 111 and the lower metal spacer ring 112 move axially toward each other, the fluid delivery channel 115 is responsible for supplying lubricating fluid to the stagnation area. That is, during the setting operation, the upper metal spacer ring 111 moves downward axially, and the upper metal spacer ring 111 and the lower metal spacer ring 112 undergo opposing squeezing movements. The axial distance between the two continuously decreases, and the volume of the movable cavity 114 is continuously compressed, forcing its internal pressure to increase.

[0022] In this way, when the lubricating fluid is delivered into the active cavity 114, since the flow cross-sectional area of ​​the fluid delivery channel 115 is smaller than the cross-sectional area of ​​the active cavity 114, the high-pressure lubricating fluid can only be ejected outward in the form of a high-speed jet through the fluid delivery channel 115. The high-pressure fluid directly impacts the gravel accumulated in the stagnation area. The dispersed gravel diffuses upward into the space under the entrainment of the jet, preventing the gravel from continuously accumulating in the stagnation area at the end of the rubber sleeve body 101, and preventing the rubber sleeve body 101 from being squeezed and scratched by the stagnant gravel when it is subjected to axial pressure.

[0023] The lubricating fluid ejected from the fluid delivery channel 115 will directly mix into the oil-gas and gravel mixture working fluid inside the wellbore. On the one hand, it can form an oil film to protect the outer wall of the rubber sleeve body 101 around the stagnation area in advance, reducing abrasive wear during the subsequent axial sliding process of unsealing. On the other hand, the lubricating fluid can move upward with the gravel mixture, preventing the gravel from accumulating again in the stagnation area, thereby improving the friction conditions between the rubber sleeve body 101 and the oil casing 104 and reducing the axial drag resistance during the unsealing operation.

[0024] The fluid replenishment mechanism includes a shaft cylinder 130 fixedly mounted on an outer ring 113 and a piston rod 131 slidably mounted in a collection chamber inside the shaft cylinder 130. The outer ring 113 has a discharge channel 135 that connects the movable chamber 114 and the collection chamber, and a suction channel 133 that connects the collection chamber and the stagnation area. When the sealing operation is performed, the piston rod 131 is used to squeeze the lubricant into the movable chamber 114 through radial movement. As the volume of the movable chamber 114 is continuously compressed and pressurized, a negative pressure is forced to form in the suction channel 133, thereby transporting the lubricant to the gravel stagnation area and flushing the accumulated gravel. As the shaft cylinder 130 gradually approaches the lower metal spacer ring 112, the channel for the solution to flow into the pumping channel 133 narrows, further improving the pumping effect of the pumping channel 133 on the diffused gravel.

[0025] See again Figure 8 As shown, the fluid replenishment mechanism also includes a power block 132 disposed within the movable cavity 114 (the power block 132 is in the state as shown). Figure 6, Figure 7 As shown), the power block 132 and the piston rod 131 are connected by a connecting rod, and a compression spring 136 is elastically connected between the piston rod 131 and the outer ring 113; Working principle: First, the power block 132 has inclined surfaces at the corresponding positions of the upper metal spacer 111 and the lower metal spacer 112. During the setting operation, the upper metal spacer 111 moves axially downward with the upper rubber sleeve seat 100. Under the guidance of the inclined surface, the upper metal spacer 111 and the lower metal spacer 112 apply pressure to the inclined surface to form an axial extrusion thrust. The power block 132 drives the piston rod 131 to make radial compression movement inside the liquid collection chamber of the shaft cylinder 130 through the connecting rod. The piston rod 131 extrudes the internal space of the liquid collection chamber and pushes the lubricating fluid in the liquid collection chamber into the movable chamber 114 through the liquid discharge channel 135. During the above process, a drain channel 134 is also provided on the shaft cylinder 130. Both the drain channel 134 and the suction channel 133 are equipped with one-way check valves. When the piston rod 131 squeezes the lubricating fluid, the check valve in the drain channel 134 is in the cut-off state, while the check valve in the suction channel 133 is used to supply external solution to the shaft cylinder 130. Conversely, when the piston rod 131 drains the fluid, the check valve in the suction channel 133 is in the cut-off state, while the check valve in the drain channel 134 is used to discharge the solution from the shaft cylinder 130. As the upper metal spacer ring 111 and the lower metal spacer ring 112 continue to move closer together, the sealed volume of the movable cavity 114 continuously decreases, and the pressure inside the cavity increases. Under the action of pressure difference, the lubricating fluid in the movable cavity 114 is sprayed into the sand and gravel retention area through the infusion channel 115. Under the throttling effect of the infusion channel 115, the flow rate of the sprayed lubricating fluid can be increased, ensuring the supply strength of the lubricating fluid to the retention area, so as to carry away and disperse the loose sand and gravel, avoid the accumulation of sand and gravel in the retention area, and prevent the rubber sleeve body 101 from being squeezed and scratched by sharp sand and gravel during the pressure process.

[0026] In other words, by using the opposing movement of the upper metal spacer ring 111 and the lower metal spacer ring 112 during the setting process, the replenishing mechanism is driven to spray the lubricant into the retention area, forcing the accumulated gravel to diffuse into the mixed solution. At the same time, the replenishing mechanism further attracts the gravel in the mixed solution through the negative pressure effect formed at the liquid extraction channel 133, inhibiting the secondary accumulation of gravel in the retention area, thereby preventing the rubber sleeve body 101 from being squeezed and scratched by the gravel when it expands, thus improving the service life of the rubber sleeve body 101.

[0027] Following this, as the piston rod 131 advances axially, the compression spring 136 is further compressed, continuously accumulating elastic potential energy. After the setting and pressure holding stage ends, the downward pressure applied by the upper metal spacer ring 111 to the power block 132 gradually weakens, and the compression spring 136 in the compressed state releases its elastic force, pulling the piston rod 131 to slide axially in the opposite direction along the shaft cylinder 130. The piston rod 131 discharges the pumped solution from the drain channel 134. That is, during the unsealing operation, the upper metal spacer ring 111 moves axially upward, and the internal volume of the movable cavity 114 increases to form a negative pressure environment. Under the action of pressure difference, the lubricant in the mixed solution flows through the stagnation area again, forming a uniform lubricating oil film on the axial sliding friction surface of the rubber sleeve body 101 and the oil sleeve 104, reducing abrasive wear, reducing unsealing pull-out resistance, and avoiding the phenomenon of sand and gravel jamming.

[0028] During the unsealing phase, the mixed solution is drawn at the infusion channel 115 by the replenishment mechanism, and the lubricant in the mixed solution is continuously guided to the stagnation area. A continuous lubricating oil film is formed on the friction surface of the rubber sleeve body 101 and the oil sleeve 104 during the retraction process, which reduces the wear of the rubber sleeve body 101 and the unsealing pull-out resistance.

[0029] Further reference Figure 9 As shown in the figure, the suction effect on the diffused gravel is illustrated. An inner slope groove 120 is formed on the lower metal spacer ring 112 to accommodate the dispersed gravel. The inner slope groove 120 gradually narrows in cross-sectional area from the retention area to the outer circumference of the lower metal spacer ring 112. The purpose is that when the lubricating fluid is sprayed from the infusion channel 115 to flush the gravel, the dispersed gravel is collected and settled in the inner slope groove 120 under the negative pressure traction and gravity of the suction channel 133. The gradually narrowing cross-section of the inner slope groove 120 increases the backflow resistance of the gravel, avoids the gravel from falling back and accumulating in the retention area, and prevents the gravel from causing abrasive wear on the rubber sleeve body 101 during the unsealing operation. Furthermore, during the unsealing process, the upper metal spacer ring 111 moves upward first, and under the elastic action of the compression spring 136, it pushes the piston rod 131 to move in the opposite direction. This generates a negative pressure in the active cavity 114 that attracts the stagnation area, thereby drawing the mixed solution towards the stagnation area. This forms a lubrication compensation for the friction between the rubber sleeve body 101 and the oil sleeve 104 in the stagnation area, reducing the wear of the rubber sleeve body 101. To further enhance the anti-backflow effect of the gravel, several anti-backflow inner grooves are provided on the inner wall of the inner slope groove 120 to restrict the backflow of gravel to the stagnation area. The anti-backflow inner grooves are opened towards the outer circumference of the lower metal spacer ring 112. In this way, even if a negative pressure suction effect is formed in the stagnation area during the unsealing stage, the gravel collected in the inner slope groove 120 will be limited and stopped in the anti-backflow inner groove, and cannot flow back to the stagnation area along the groove. This achieves the collection and isolation of gravel and improves the service life of the rubber sleeve body 101.

[0030] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A sand-proof packer, comprising an upper rubber sleeve seat (100), a lower rubber sleeve seat (102), a slip assembly (103), and a plurality of rubber sleeve bodies (101) disposed between the upper rubber sleeve seat (100) and the lower rubber sleeve seat (102), wherein the rubber sleeve bodies (101) abut against the inner wall of the oil casing (104), characterized in that: A spacer mechanism (110) is provided between adjacent rubber sleeve bodies (101) to axially separate the two rubber sleeve bodies (101). The spacer mechanism (110) includes an upper metal spacer (111) fixed to the end of the upper rubber sleeve body (101) and a lower metal spacer (112) fixed to the end of the lower rubber sleeve body (101). A fluid replenishment mechanism is provided between the upper metal spacer (111) and the lower metal spacer (112). The lower metal spacer (112) and the inner wall of the oil casing (104) enclose a gravel retention area for accommodating downhole gravel. When the upper rubber sleeve seat (100) moves axially downward to perform the setting and sealing operation, the upper metal spacer ring (111) and the lower metal spacer ring (112) undergo opposing squeezing motion, which drives the replenishing mechanism to spray and supply its internal lubricant to the stagnation area to disperse the sand and gravel in the stagnation area. At the same time, the replenishing mechanism guides the dispersed sand and gravel to the outer circumference of the lower metal spacer ring (112). During the unsealing operation, a negative pressure suction effect is formed in the fluid replenishment mechanism, which forces the lubricant to be transported in a directional manner to the retention area. A lubricating oil film is formed at the position where the rubber sleeve body (101) and the oil sleeve (104) have axial relative sliding friction, so as to achieve lubrication compensation for the axial friction of the rubber sleeve body (101).

2. The sand control packer of claim 1, wherein: An outer ring (113) is coaxially sleeved on the outside of the upper metal spacer (111) and the lower metal spacer (112). Inner retaining rings (117) are fixed at both the upper and lower ends of the outer ring (113). Inner retaining rings (117) are fixed on the outside of both the upper metal spacer (111) and the lower metal spacer (112). Outer retaining rings (116) are formed axially on the outer peripheral walls of the upper metal spacer (111) and the lower metal spacer (112). The inner retaining ring (117) is slidably disposed with the outer retaining ring (116), and the outer retaining ring (116) forms a radial constraint on the inner retaining ring (117).

3. The sand control packer of claim 2, wherein: The upper metal spacer (111), lower metal spacer (112), outer ring (113), and inner tube (105) together form a movable cavity (114). The lower metal spacer (112) has a fluid delivery channel (115) that connects the movable cavity (114) and the stagnation area. When the upper metal spacer (111) and the lower metal spacer (112) move axially toward each other, the fluid delivery channel (115) is responsible for supplying lubricating fluid to the stagnation area.

4. The sand control packer of claim 3, wherein: The flow cross-sectional area of ​​the infusion channel (115) is smaller than the cross-sectional area of ​​the movable cavity (114).

5. The sand control packer of claim 3, wherein: The replenishment mechanism includes a cylinder (130) fixedly mounted on an outer ring (113) and a piston rod (131) slidably mounted in a collection chamber inside the cylinder (130). The outer ring (113) has a discharge channel (135) that connects the movable chamber (114) and the collection chamber, and a suction channel (133) that connects the collection chamber and the retention area. When the sealing operation is performed, the piston rod (131) is used to discharge the lubricant into the movable chamber (114) by radial movement, forcing a negative pressure suction to be formed in the suction channel (133).

6. The sand control packer of claim 5, wherein: The fluid replenishment mechanism also includes a power block (132) disposed in the movable cavity (114). The power block (132) is connected to the piston rod (131) by a connecting rod. A compression spring (136) is elastically connected between the piston rod (131) and the outer ring (113).

7. The sand control packer of claim 6, wherein: The power block (132) has inclined surfaces at the corresponding positions of the upper metal spacer (111) and the lower metal spacer (112).

8. The sand control packer of claim 5, wherein: The shaft (130) is also provided with a drain channel (134). Both the drain channel (134) and the pumping channel (133) are equipped with one-way check valves. The check valve located in the pumping channel (133) is used to supply external solution to the shaft (130); the check valve located in the drain channel (134) is used to supply solution in the shaft (130) to the outside.

9. The sand control packer of claim 1, wherein: An inner slope groove (120) is formed on the lower metal spacer ring (112) to accommodate the dispersed gravel. The inner slope groove (120) has a gradually decreasing cross-sectional area from the retention area to the outer periphery of the lower metal spacer ring (112).

10. The sand control packer of claim 9, wherein: Several anti-backflow inner channels are provided on the inner wall of the inner slope channel (120) to restrict the backflow of sand and gravel to the retention area. The anti-backflow inner channels are opened towards the outer peripheral surface of the lower metal spacer ring (112).

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