Completion technology for sandstone reinjection wells

Abstract

The present invention provides a completion process suitable for sandstone reinjection wells, including the steps of pipe assembly, preliminary lowering, gravel filling, feeding lowering, circulation filling and pipe recovery. After the pipe assembly step is completed, the preliminary lowering step is started, and the assembly formed in the pipe assembly step is lowered to the sandstone layer of the reinjection well by a lowering device. Subsequently, gravel is filled into each perforation corresponding to the sandstone layer through the gravel filling step, the feeding lowering step and the circulation filling step, and a water filter pipe is installed at the same time. Finally, the filling mechanism is recovered to the ground through the pipe recovery step. The completion process suitable for sandstone reinjection wells provided by the present invention fills gravel by feeding, and gravel is filled into each perforation corresponding to the sandstone layer of the reinjection well, which can ensure that the gravel in each perforation is saturated, thereby ensuring the gravel filling effect, and has strong practicality.

Description

Technical Field

[0001] The invention belongs to the technical field of sand prevention of reinjection wells, and in particular relates to a well completion process suitable for sandstone reinjection wells. Background Art

[0002] Geothermal water refers to water with a higher temperature formed by geothermal heating deep underground. It is a renewable energy source and can be used for heating. In order to maintain the sustainability of geothermal resources, recharge wells are usually set up to allow the low-temperature geothermal water to flow back into the underground reservoir after the heat is collected to maintain the pressure of the reservoir. The mining of recharge wells usually encounters sandstone geological formations, so gravel filling is required after perforation to achieve the purpose of sand control.

[0003] In current technology, gravel filling is usually done by injecting gravel into the bottom of the filter pipe through a filling pipeline after the filter pipe is lowered, and the gravel is introduced to the outside of the filter pipe through the bottom of the filter pipe and enters each perforation at the same time to achieve gravel filling. However, the fluidity of gravel is poor. When the filling length is large, the amount of gravel entering each perforation corresponding to the upper part of the filter pipe will decrease, which will lead to poor gravel filling effect and poor practicality. Summary of the invention

[0004] The embodiment of the present invention provides a completion process applicable to a sandstone reinjection well, aiming to solve the problem of poor practicability of the existing sandstone reinjection well completion process due to poor gravel filling effect.

[0005] To achieve the above object, the technical solution adopted by the present invention is: to provide a completion process suitable for sandstone reinjection wells, comprising the following steps:

[0006] The pipe fittings are assembled, the filter pipe is vertically arranged, the filling mechanism penetrates the lumen of the filter pipe from top to bottom, and the filling mechanism is fixedly and sealedly connected with the bottom of the lumen of the filter pipe; a packer is sleeved on the bottom end of the filter pipe;

[0007] Initially lowering, by lowering the assembly formed in the pipe assembly step to the sandstone layer of the reinjection well through a lowering device connected to the filling mechanism, so that the packer is located at the top of the sandstone layer and the bottom of the filling mechanism corresponds to the perforation position at the top of the sandstone layer;

[0008] Gravel filling: start the packer and expand the expansion part at the bottom of the filling mechanism to form an annular space connected with each perforation between the packer and the expansion part; inject gravel into the filling mechanism through the lowering device so that the gravel is filled from the annular space into each perforation;

[0009] Feeding and lowering, releasing the blockage of the packer, and at the same time releasing the blockage of the expansion part, driving the combination of the water filter pipe and the filling mechanism to descend in a feeding manner through the lowering equipment;

[0010] Circular filling, repeating the gravel filling step and the feeding and lowering step in sequence until the bottom end of the water filter pipe contacts the bottom end of the recharging well;

[0011] After the pipe is recovered and the packer is activated, the fixed connection between the filling mechanism and the water filter pipe is released, and the blockage of the expansion part is released, and the filling mechanism is pulled out of the recharging well by lowering equipment.

[0012] In a possible implementation, the filling mechanism includes:

[0013] A fixed pipe having a tube cavity, wherein the end of the fixed pipe extending out of the water filter pipe is provided with a plurality of outlets, and each of the outlets is arranged at annular intervals around the axis of the fixed pipe;

[0014] A sealing structure, which is fixedly sleeved on the fixed pipe and located above each of the outlets, and is used to seal the lumen of the water filter pipe at the bottom of the water filter pipe;

[0015] A hole sealing component is connected to the bottom end of the fixed pipe. The hole sealing component is the expansion part. The hole sealing component is used to seal the recharging well after expansion.

[0016] In a possible implementation, the sealing component includes:

[0017] An upper fixed circular plate is coaxially arranged with the fixed tube, and the top of the upper fixed circular plate is connected to the bottom of the fixed tube via a connecting tube;

[0018] A lower fixed circular plate is located below the upper fixed circular plate and is arranged parallel to the upper fixed circular plate, and the lower fixed circular plate is connected to the upper fixed circular plate through a column;

[0019] A first rubber sleeve is annularly arranged between the upper fixed circular plate and the lower fixed circular plate, with a top end connected to the upper fixed circular plate and a bottom end connected to the lower fixed circular plate, wherein the first rubber sleeve, the upper fixed circular plate and the lower fixed circular plate together form a first expansion chamber;

[0020] An interception ring is sleeved on the outer circumference of the upper fixed circular plate and is detachably connected to a clamping structure disposed in the upper fixed circular plate, and is used to intercept gravel in the annular space during the downward movement of the water filter pipe;

[0021] A driving structure is connected to the first expansion chamber and is used to drive the first expansion chamber to contract.

[0022] In a possible implementation, the diameters of the upper fixed circular plate and the lower fixed circular plate are equal, and both are smaller than the inner diameter of the water filter pipe.

[0023] In a possible implementation, the outer diameter of the interception ring is smaller than the pore diameter of the sandstone layer in the reinjection well.

[0024] In a possible implementation, the clamping structure includes:

[0025] A plurality of plug-in slides are provided, each of which is arranged in an annular manner in the upper fixed circular plate, and each of which is slidably connected to the upper fixed circular plate along the radial direction of the upper fixed circular plate, and the outer end of each of the plug-in slides can extend out of the upper fixed circular plate;

[0026] A first hydraulic pump connected to a first fluid outlet provided on a side wall of the connecting pipe through a pipeline;

[0027] The upper fixed circular plate is provided with an inner cavity connected to the connecting pipe, and is provided with a plurality of sliding cavities connected to the inner cavities and for sliding connection of the plug-in sliding posts one by one;

[0028] Wherein, the interception ring is provided with a plurality of insertion holes for the insertion of the plug-in sliding posts.

[0029] In a possible implementation, the driving structure includes a second hydraulic pump, and the second hydraulic pump is connected to a second fluid outlet provided on the upper fixed circular plate through a pipeline.

[0030] In a possible implementation, the sealing structure includes:

[0031] An upper fixed ring, fixedly sleeved on the fixed tube;

[0032] A lower fixed circular ring, which is fixedly sleeved on the fixed tube and is located below the upper fixed circular ring;

[0033] The second rubber sleeve is annularly arranged between the upper fixed ring and the lower fixed ring, and the top end is connected to the upper fixed ring, and the bottom end is connected to the lower fixed ring. The second rubber sleeve, the upper fixed ring and the lower fixed ring form a second expansion chamber.

[0034] In a possible implementation, the lowering equipment is a drilling rig.

[0035] In this implementation, the filling mechanism connected to the lowering device can fix the filter pipe and drive the filter pipe into the recharge well. After the filter pipe is lowered to the top of the sandstone layer, the packer is fixed, and the perforations corresponding to the top of the sandstone layer are filled through the gravel filling step, and then the gravel is gradually filled into each perforation of each sandstone layer from top to bottom through the feeding and lowering step and the circulation filling step, and the filter pipe is fixed by the packer. This method uses the feeding method to fill the perforations corresponding to the sandstone layer of the recharge well with gravel, which can ensure that the gravel in each perforation is saturated, thereby ensuring the gravel filling effect, and has strong practicality. In addition, the filling mechanism can be pulled out of the recharge well through the pipe recovery step to achieve recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A flow chart of a completion process applicable to a sandstone reinjection well provided in an embodiment of the present invention;

[0037] Figure 2 A schematic structural diagram of the initial lowering step and the gravel filling step of a completion process applicable to a sandstone reinjection well provided in an embodiment of the present invention;

[0038] Figure 3 A structural schematic diagram of a feeding and lowering step and a circulating filling step of a completion process applicable to a sandstone reinjection well provided in an embodiment of the present invention;

[0039] Figure 4 A structural schematic diagram of a pipe recovery step in a completion process applicable to a sandstone reinjection well provided in an embodiment of the present invention;

[0040] Figure 5 for Figure 3 The enlarged structural schematic diagram of point A of the completion technology suitable for sandstone reinjection wells is shown.

[0041] Description of reference numerals:

[0042] 10. Filling mechanism; 11. Fixed pipe; 12. Sealing structure; 121. Upper fixed ring; 122. Lower fixed ring; 123. Second rubber sleeve; 13. Sealing assembly; 131. Upper fixed circular plate; 132. Lower fixed circular plate; 133. First rubber sleeve; 134. Intercepting ring; 135. Driving structure; 136. Clamping structure; 1361. Inserting slide column; 1362. First hydraulic pump; 1363. Inner cavity; 1364. Insert hole;

[0043] 20. Packer;

[0044] 30. Water filter pipe;

[0045] 40. Perforation;

[0046] 50. Lower the equipment. DETAILED DESCRIPTION

[0047] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0048] Please also read Figures 1 to 4 The completion process for sandstone reinjection wells provided by the present invention is now described. The completion process for sandstone reinjection wells includes the steps of pipe assembly, initial lowering, gravel filling, feed lowering, circulation filling and pipe recovery.

[0049] S100: Assemble the pipes, vertically set the filter pipe 30, make the filling mechanism 10 penetrate the lumen of the filter pipe 30 from top to bottom, and make the filling mechanism 10 fixedly and sealedly connected with the lumen bottom of the filter pipe 30. Set the packer 20 at the bottom end of the filter pipe 30.

[0050] S200: Initial lowering: lower the assembly formed in the pipe assembly step to the sandstone layer of the reinjection well through the lowering device 50 connected to the filling mechanism 10, so that the packer 20 is located at the top of the sandstone layer, and the bottom of the filling mechanism 10 corresponds to the perforation 40 position at the top of the sandstone layer.

[0051] S300: Gravel filling, start the packer 20, and expand the expansion part at the bottom of the filling mechanism 10, so that an annular space connected to each perforation 40 is formed between the packer 20 and the expansion part. Gravel is injected into the filling mechanism 10 through the lowering device 50, so that the gravel is filled into each perforation 40 from the annular space.

[0052] S400: feeding and lowering, releasing the blockage of the packer 20 and the expansion part, and driving the combination of the filter pipe 30 and the filling mechanism 10 downward in a feeding manner through the lowering device 50.

[0053] S500: Circular filling, repeating the gravel filling step and the feeding and lowering step in sequence until the bottom end of the water filter pipe 30 contacts the bottom end of the recharging well.

[0054] S600: After the pipe is recovered, the packer 20 is activated, the fixed connection between the filling mechanism 10 and the water filter pipe 30 is released, and the plugging of the expansion part is released, and the filling mechanism 10 is pulled out of the reinjection well by the lowering device 50.

[0055] The completion process suitable for sandstone recharge wells provided in this embodiment is compared with the prior art. The filling mechanism 10 connected to the lowering device 50 can fix the water filter pipe 30 and drive the water filter pipe 30 into the recharge well. After the water filter pipe 30 is lowered to the top of the sandstone layer, the packer 20 is fixed, and the perforations 40 corresponding to the top of the sandstone layer are filled through the gravel filling step, and then the gravel is gradually filled into each perforation 40 of each sandstone layer from top to bottom through the feeding and lowering step and the circulation filling step, and the water filter pipe 30 is fixed by the packer 20. This method uses the feeding method to fill the gravel into each perforation 40 corresponding to the sandstone layer of the recharge well, which can ensure that the gravel in each perforation 40 is saturated, thereby ensuring the gravel filling effect, and has strong practicality. In addition, the filling mechanism 10 can be pulled out of the recharge well through the pipe recovery step to achieve recovery.

[0056] It should be noted that the feed-type lowering means that the sandstone layer is divided into multiple sections from top to bottom, and each feed-lowering step descends one of the sections. The bottom of the sandstone layer can be the bottom of the recharging well, and of course, an annular platform can be opened at the bottom of the sandstone layer (formed during the drilling process).

[0057] In addition, the packer 20 may be a self-sealing packer 20, and the position of the packer 20 always remains stationary, and may be specifically limited by an annular platform formed during the drilling process at the top of the sandstone layer.

[0058] In some embodiments, the filling mechanism 10 may be configured as follows: Figures 2 to 4 See the structure shown. Figures 2 to 4 The filling mechanism 10 includes a fixed pipe 11, a sealing structure 12 and a sealing assembly 13. The fixed pipe 11 has a lumen, and the end of the fixed pipe 11 extending out of the water filter pipe 30 is provided with a plurality of outlets, and each outlet is arranged in a ring-shaped interval around the axis of the fixed pipe 11. The sealing structure 12 is fixedly sleeved on the fixed pipe 11 and is located above each outlet. The sealing structure 12 can block the lumen of the water filter pipe 30 at the bottom of the water filter pipe 30. The sealing assembly 13 is connected to the bottom end of the fixed pipe 11, and the sealing assembly 13 is an expansion part. The sealing assembly 13 can seal the recharge well after expansion.

[0059] The fixed pipe 11 can ensure connection with the lowering equipment 50, and the fixed pipe 11 can be composed of multiple sections of pipe monomers that can be connected by threads to adapt to different lengths of water filter pipes 30, and thus correspond to sandstone layers of different depths. The isolation structure 12 is arranged at the bottom end of the fixed pipe 11, which can be sealed with the bottom end of the tube cavity of the water filter pipe 30, and at the same time can ensure that the water filter pipe 30 is driven to move, and the outlet provided at the lower position of the fixed pipe 11 located at the lower position of the isolation structure 12 can ensure the export of gravel. The sealing component 13 is arranged at the bottom end of the fixed pipe 11, which can expand below the water filter pipe 30 and contact with the inner wall of the recharging well, thereby realizing the sealing of the position below the water filter pipe 30, forming an annular space corresponding to multiple perforations 40, so as to ensure that the gravel injected by the fixed pipe 11 enters each perforation 40 through the annular space.

[0060] In some embodiments, the sealing component 13 may be used as follows: Figure 3 to Figure 4 See the structure shown. Figure 3 to Figure 4 The sealing assembly 13 includes an upper fixed circular plate 131, a lower fixed circular plate 132, a first rubber sleeve 133, an intercepting ring 134 and a driving structure 135. The upper fixed circular plate 131 is coaxially arranged with the fixed tube 11, and the top is connected to the bottom end of the fixed tube 11 through a connecting tube. The lower fixed circular plate 132 is located below the upper fixed circular plate 131 and is arranged parallel to the upper fixed circular plate 131. The lower fixed circular plate 132 is connected to the upper fixed circular plate 131 through a column. The first rubber sleeve 133 is annularly arranged between the upper fixed circular plate 131 and the lower fixed circular plate 132, and the top end is connected to the upper fixed circular plate 131, and the bottom end is connected to the lower fixed circular plate 132. The first rubber sleeve 133, the upper fixed circular plate 131 and the lower fixed circular plate 132 enclose a first expansion chamber. The interception ring 134 is sleeved on the outer circumference of the upper fixed circular plate 131 and is detachably connected to the clamping structure 136 disposed in the upper fixed circular plate 131, and can intercept gravel in the annular space during the downward movement of the water filter pipe 30. The driving structure 135 is connected to the first expansion chamber and can drive the first expansion chamber to contract.

[0061] The upper fixed circular plate 131 and the lower fixed circular plate 132 can limit the first rubber sleeve 133 in the vertical direction to ensure that the first rubber sleeve 133 only extends radially outward along the upper fixed circular plate 131 and the lower fixed circular plate 132 after the driving structure 135 is pressurized, and abuts against the inner wall of the reinjection well to achieve blocking of the reinjection well.

[0062] The interception ring 134 can be detachably connected through the clamping structure 136 on the upper fixed circular plate 131. Because the first rubber sleeve 133 in the sealing assembly 13 is in a contracted state when the filling mechanism 10 drives the filter pipe 30 downward, the gravel above will leak to the bottom outside the sealing assembly 13. At this time, the gravel can be intercepted by the interception ring 134 to avoid leakage of the gravel and also avoid loss of the gravel. The interception ring 134 can be fixed by the clamping structure 136, and can also remain at the bottom of the filter pipe 30 after the clamping structure 136 is released, thereby facilitating the smooth progress of the pipe recovery step.

[0063] In some embodiments, the sealing component 13 may be used as follows: Figure 3 to Figure 4 See the structure shown. Figure 3 to Figure 4 The diameters of the upper fixed circular plate 131 and the lower fixed circular plate 132 are equal and smaller than the inner diameter of the water filter pipe 30. This structure can ensure that the sealing assembly 13 can pass through the water filter pipe 30 during the pipe recovery step to ensure that it is pulled back to the ground. The upper fixed circular plate 131 and the lower fixed circular plate 132 can both be made of metal.

[0064] In some embodiments, the sealing component 13 may be used as follows: Figure 3 to Figure 4 See the structure shown. Figure 3 to Figure 4 The outer diameter of the interception ring 134 is smaller than the aperture of the sandstone layer of the reinjection well, and the inner diameter is adapted to the outer diameter of the upper fixed circular plate 131 to ensure that the interception ring 134 can move freely with the sealing assembly 13.

[0065] In some embodiments, the sealing component 13 may be used as follows: Figures 3 to 5 See the structure shown. Figures 3 to 5 The clamping structure 136 includes a plug-in slide 1361 and a first hydraulic pump 1362. A plurality of plug-in slides 1361 are provided, each plug-in slide 1361 is annularly spaced and arranged in the upper fixed circular plate 131, and each plug-in slide 1361 is slidably connected to the upper fixed circular plate 131 along the radial direction of the upper fixed circular plate 131, and the outer end of each plug-in slide 1361 can extend out of the upper fixed circular plate 131. The first hydraulic pump 1362 is connected to the first liquid outlet arranged on the side wall of the connecting pipe through a pipeline.

[0066] Specifically, the upper fixed circular plate 131 is provided with an inner cavity 1363 communicating with the connecting pipe, and is provided with a plurality of sliding cavities communicating with each inner cavity 1363 and for each plug-in sliding post 1361 to be slidably connected one by one.

[0067] Specifically, the interception ring 134 is provided with a plurality of insertion holes 1364 for the insertion of the plug-in slide posts 1361 .

[0068] The first hydraulic pump 1362 injects hydraulic oil into the connecting pipe and the inner cavity 1363, so that each plug-in slide post 1361 extends outward and is inserted into each plug hole 1364 on the interception ring 134, thereby achieving fixed connection of the interception ring 134, thereby ensuring that the interception ring 134 can move up and down with the upper fixed circular plate 131. When the first hydraulic pump 1362 extracts the hydraulic oil from the connecting pipe and the inner cavity 1363, each interception ring 134 will move inward and be retracted into each slide cavity, and the position limit clamping of the interception ring 134 will be released at this time. This structure can realize the release of the interception ring 134, thereby ensuring the progress of the pipe recovery step.

[0069] In some embodiments, the sealing component 13 may be used as follows: Figure 3 to Figure 4 See the structure shown. Figure 3 to Figure 4 The driving structure 135 includes a second hydraulic pump, which is connected to a second fluid outlet disposed on the upper fixed circular plate 131 through a pipeline. The second hydraulic pump can ensure that the first rubber sleeve 133 is driven, thereby ensuring the expansion and contraction of the first rubber sleeve 133.

[0070] In some embodiments, the sealing component 13 may be used as follows: Figure 3 to Figure 4 See the structure shown. Figure 3 to Figure 4 The sealing structure 12 includes an upper fixed ring 121, a lower fixed ring 122 and a second rubber sleeve 123. The upper fixed ring 121 is fixedly sleeved on the fixed tube 11. The lower fixed ring 122 is fixedly sleeved on the fixed tube 11 and is located below the upper fixed ring 121. The second rubber sleeve 123 is annularly arranged between the upper fixed ring 121 and the lower fixed ring 122, and the top end is connected to the upper fixed ring 121, and the bottom end is connected to the lower fixed ring 122. The second rubber sleeve 123, the upper fixed ring 121 and the lower fixed ring 122 enclose a second expansion chamber.

[0071] The upper fixed ring 121 and the lower fixed ring 122 are fixedly connected to the fixed tube 11, and can limit the vertical position of the second rubber sleeve 123 therebetween to ensure that the second rubber sleeve 123 only extends radially outward from the water filter tube 30 during expansion, thereby ensuring that it abuts against the inner wall of the water filter tube 30, thereby sealing the bottom end of the water filter tube 30 and facilitating the formation of an annular space.

[0072] The sealing structure 12 and the sealing assembly 13 are spaced apart, and each outlet is located between the sealing structure 12 and the sealing assembly 13 .

[0073] In addition, regarding the pipelines connected to the first hydraulic pump 1362 and the second hydraulic pump, two rigid pipelines can be fixedly connected between the upper fixed ring 121 and the lower fixed ring 122, and the two rigid pipelines serve as the corresponding pipelines of the first hydraulic pump 1362 and the second hydraulic pump respectively.

[0074] Of course, the contraction of the second rubber sleeve 123 can be controlled by a third hydraulic pump connected to the second expansion chamber through a pipeline. There is no obstruction to the pipeline connected to the third hydraulic pump, so the pipeline can be directly connected to the third liquid outlet arranged on the upper fixed ring 121. This technology is existing technology and will not be repeated here.

[0075] It should be noted that the outer diameters of the upper fixing ring 121 and the lower fixing ring 122 may be equal to the diameters of the upper fixing circular plate 131 and the lower fixing circular plate 132 .

[0076] In some embodiments, the lowering equipment 50 is a drilling rig, which is convenient for connecting the fixed pipe 11 and lowering the fixed pipe 11 into the reinjection well. The specific drilling rig is detachably connected to the fixed pipe 11 through a drill rod, and gravel can be injected into the fixed pipe 11 through the drill rod. The method of injecting gravel is existing technology and will not be repeated here.

[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. Applicable to the completion technology of sandstone reinjection wells, It is characterized in that The steps include: The pipe fittings are assembled, the filter pipe is vertically arranged, the filling mechanism penetrates the lumen of the filter pipe from top to bottom, and the filling mechanism is fixedly and sealedly connected with the bottom of the lumen of the filter pipe; a packer is sleeved on the bottom end of the filter pipe; Initially lowering, by lowering the assembly formed in the pipe assembly step to the sandstone layer of the reinjection well through a lowering device connected to the filling mechanism, so that the packer is located at the top of the sandstone layer and the bottom of the filling mechanism corresponds to the perforation position at the top of the sandstone layer; Gravel filling, starting the packer, and at the same time expanding the expansion part arranged at the bottom end of the filling mechanism, so that an annular space connected with each perforation is formed between the packer and the expansion part; Injecting gravel into the filling mechanism by lowering equipment, so that the gravel is filled from the annular space into each of the perforations; Feeding and lowering, releasing the blockage of the packer, and at the same time releasing the blockage of the expansion part, driving the combination of the water filter pipe and the filling mechanism to descend in a feeding manner through the lowering equipment; Circular filling, repeating the gravel filling step and the feeding and lowering step in sequence until the bottom end of the water filter pipe contacts the bottom end of the recharging well; After the pipe is recovered and the packer is activated, the fixed connection between the filling mechanism and the water filter pipe is released, and the plugging of the expansion part is released, and the filling mechanism is pulled out of the recharging well by lowering equipment; The filling mechanism comprises a fixed pipe, a sealing structure and a sealing assembly; the fixed pipe has a lumen, and the end of the fixed pipe extending out of the water filter pipe is provided with a plurality of outlets, each of which is arranged at annular intervals around the axis of the fixed pipe; the sealing structure is fixedly sleeved on the fixed pipe and located above each of the outlets, and the sealing structure is used to seal the lumen of the water filter pipe at the bottom of the water filter pipe; the sealing assembly is connected to the bottom end of the fixed pipe, and the sealing assembly is the expansion part, and the sealing assembly is used to seal the recharge well after expansion; Wherein, the sealing assembly comprises an upper fixed circular plate, a lower fixed circular plate, a first rubber sleeve, an intercepting ring and a driving structure; the upper fixed circular plate is coaxially arranged with the fixed tube, and the top is connected to the bottom end of the fixed tube through a connecting tube; the lower fixed circular plate is located below the upper fixed circular plate and is arranged parallel to the upper fixed circular plate, and the lower fixed circular plate is connected to the upper fixed circular plate through a column; the first rubber sleeve is annularly arranged between the upper fixed circular plate and the lower fixed circular plate, and the top end is connected to the upper fixed circular plate, and the bottom end is connected to the lower fixed circular plate, the first rubber sleeve, the upper fixed circular plate and the lower fixed circular plate enclose a first expansion chamber; the intercepting ring is arranged on the outer circumference of the upper fixed circular plate, and is detachably connected to the clamping structure arranged in the upper fixed circular plate, and is used for the process of the water filter pipe descending. The gravel in the annular space is intercepted; the outer diameter of the interception ring is smaller than the aperture at the sandstone layer of the reinjection well; the driving structure is connected to the first expansion chamber for driving the first expansion chamber to contract; the clamping structure includes a plug-in slide and a first hydraulic pump; there are multiple plug-in slides, each of which is arranged in the upper fixed circular plate at an annular interval, and each of the plug-in slides is slidably connected to the upper fixed circular plate along the radial direction of the upper fixed circular plate, and the outer end of each plug-in slide can extend out of the upper fixed circular plate; the first hydraulic pump is connected to the first liquid outlet arranged on the side wall of the connecting pipe through a pipeline; the upper fixed circular plate is provided with an inner cavity connected to the connecting pipe, and is provided with a plurality of sliding cavities connected to each of the inner cavities and for each of the plug-in slides to be slidably connected one by one; the interception ring is provided with a plurality of sockets for each of the plug-in slides to be inserted.

2. The well completion process for sandstone reinjection well according to claim 1, It is characterized in that The diameters of the upper fixed circular plate and the lower fixed circular plate are equal and are both smaller than the inner diameter of the water filter pipe.

3. The well completion process applicable to sandstone reinjection wells as claimed in claim 1, It is characterized in that The driving structure comprises a second hydraulic pump, and the second hydraulic pump is connected to a second fluid outlet arranged on the upper fixed circular plate through a pipeline.

4. The well completion process applicable to sandstone reinjection wells according to claim 1, It is characterized in that The isolation structure comprises: An upper fixed ring, fixedly sleeved on the fixed tube; A lower fixed circular ring, which is fixedly sleeved on the fixed tube and is located below the upper fixed circular ring; The second rubber sleeve is annularly arranged between the upper fixed ring and the lower fixed ring, and the top end is connected to the upper fixed ring, and the bottom end is connected to the lower fixed ring. The second rubber sleeve, the upper fixed ring and the lower fixed ring form a second expansion chamber.

5. The well completion process applicable to sandstone reinjection wells according to claim 1, It is characterized in that The lowering equipment is a drilling rig.

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