Brine well casing and brine well structure

Abstract

The present invention discloses a brine well casing and structure, relating to the field of mineral salt mining technology, and addressing the problem of brine wells being easily clogged. The present invention comprises a pipe wall and a flow channel defined by the pipe wall, wherein the pipe wall is provided with multiple through-holes connected to the flow channel. The brine well casing is configured to be installed in the horizontal section of the water injection well, and the flow channel is configured to form a connecting channel within the horizontal section. The present invention is primarily used for the manufacture of brine well casing.

Description

Technical Field

[0001] The present invention relates to the technical field of mineral salt mining, in particular to a brine mining well casing and a brine mining well structure. Background Art

[0002] At present, "U"-shaped wells, i.e., connecting wells, are widely used in the domestic brine mining industry. This type of well utilizes the connecting channel between the two wells to obtain underground mineral salt resources by injecting water from one well and producing brine from the other well. In order to obtain higher salt dissolution efficiency and increase brine production, most brine mining wells are completed by open-hole completion in the horizontal section between the water injection well and the brine production well. However, this method is mainly suitable for salt mines with shallow burial depths (vertical depths of more than 3,500m), low formation pressure coefficients, stable ore development, and high salt purity. For ultra-deep salt mines, the geological conditions are complex, the formation pressure is high, and there are many interlayers. Open-hole completion can easily cause the connecting channel to collapse, leading to blockage, and causing the brine well to be unable to be put into production. Therefore, how to avoid blockage of brine mining wells is a technical problem that technicians in this field urgently need to solve. Summary of the Invention

[0003] In view of this, an embodiment of the present invention provides a brine well casing and a brine well structure, the main purpose of which is to avoid blockage of the brine well.

[0004] On the one hand, an embodiment of the present invention provides a brine well casing for a brine well structure, wherein the brine well structure includes: a water injection well, including: a vertical well section, a deflection section, and a horizontal section connected in sequence; a brine outlet well, connected to an end of the horizontal section away from the deflection end; the brine well casing includes:

[0005] The pipe wall and the flow channel enclosed by the pipe wall, the pipe wall is formed with multiple through holes connected to the flow channel, the brine well casing is used to be set in the horizontal section of the water injection well, and the flow channel is used to form a connecting channel in the horizontal section.

[0006] The purpose of the present invention and the solution to its technical problems can be further achieved by adopting the following technical measures.

[0007] Specifically, it includes a first end and a second end relative to each other, the first end is connected to the brine outlet well, the second end is far away from the brine outlet well, and the arrangement density of the vias near the first end is greater than the arrangement density of the vias near the second end.

[0008] Specifically, the plurality of via holes are arranged on the tube wall along a spiral line.

[0009] Specifically, the phase angle between two adjacent via holes located on the same spiral line is greater than or equal to 45° and less than or equal to 60°.

[0010] Specifically, it further comprises: a plurality of perforated tubes, the plurality of perforated tubes are connected in sequence, the plurality of through holes are provided on the side walls of the perforated tubes, and the perforated tubes include opposite third and fourth ends;

[0011] A joint pipe, one end of which is used to be sleeved on the third end of any of the perforated pipes, and the other end of which is used to be sleeved on the fourth end of any other of the perforated pipes.

[0012] Specifically, the third end of the perforated tube is provided with a first fixed area, the fourth end is provided with a second fixed area, a hole distribution area is formed between the first fixed area and the second fixed area, and a plurality of through holes are provided in the hole distribution area. One end of the joint tube is used to be sleeved on part of the first fixed area of ​​any perforated tube, and the other end is used to be sleeved on part of the second fixed area of ​​any other perforated tube.

[0013] Specifically, the total area of ​​the plurality of via holes is less than or equal to 90% of the area of ​​the side wall of the perforated tube.

[0014] Specifically, a first region and a second region are sequentially provided between the first end and the second end, and an arrangement density of the via holes provided in the second region is smaller than an arrangement density of the via holes provided in the first region.

[0015] On the other hand, an embodiment of the present invention further provides a brine production well structure, the brine production well structure comprising: a water injection well, comprising: a vertical well section, a deflection section, and a horizontal section connected in sequence;

[0016] a brine outlet well connected to an end of the horizontal section away from the deflection end;

[0017] The brine well casing described in any one of the above items.

[0018] A brine well casing and structure proposed in an embodiment of the present invention includes a perforated pipe disposed in the horizontal section of the injection well to form a communication channel in the horizontal section. The flow channel of the brine well casing serves as the communication channel for the horizontal section, while through-holes are formed in the wall of the brine well casing. Therefore, water in the flow channel can enter the salt mine outside the brine well casing through the through-holes to dissolve the brine. During brine extraction, clean water is injected into the injection well. After entering the horizontal section, the clean water flows through the flow channel through the through-holes into the salt mine, dissolving the brine before entering the brine outlet well along with the water flow. The perforated pipe forms a flow channel, thereby providing support for the horizontal section, thereby preventing the communication channel from being blocked due to the collapse of the salt mine in the horizontal section.

[0019] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic structural diagram of a brine extraction well structure provided by an embodiment of the present invention;

[0021] Figure 2 Another structural schematic diagram of a brine extraction well structure provided by an embodiment of the present invention;

[0022] Figure 3 Another structural schematic diagram of a brine mining well structure provided by an embodiment of the present invention;

[0023] Figure 4 Another structural schematic diagram of a brine mining well structure provided by an embodiment of the present invention.

[0024] Description of Figure Numbers:

[0025] 11-vertical well section, 12-inclined section, 13-horizontal section, 2-brine well, 3-brine production well casing, 31-first end, 32-second end, 33-perforated pipe, 331-third end, 332-fourth end, 333-hole layout area, 334-first fixed area, 335-second fixed area, 34-through hole, 4-connector pipe. DETAILED DESCRIPTION

[0026] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the following is a detailed description of the specific implementation method, structure, characteristics and effects of the brine well casing and brine well structure proposed in accordance with the present invention, in combination with the accompanying drawings and preferred embodiments.

[0027] On the one hand, the embodiment of the present invention provides a brine well casing 3, such as Figure 1 As shown, it is used for a brine production well structure, which includes: a water injection well, including: a vertical well section 11, a deflecting section 12 and a horizontal section 13 connected in sequence; a brine outlet well 2, connected to the end of the horizontal section 13 away from the deflecting end; the brine production well casing 3 includes: a pipe wall and a flow channel surrounded by the pipe wall, and a plurality of through holes 34 connected to the flow channel are formed on the pipe wall. The brine production well casing 3 is used to be set in the horizontal section 13 of the water injection well, and the flow channel is used to form a connecting channel in the horizontal section 13.

[0028] Among them, clean water is injected into the injection well to dissolve the salt ore, and the brine enters the brine production well 2 for collection. The injection well in the brine production well structure includes a vertical well section 11, a deflection section 12, and a horizontal section 13. In the prior art, the horizontal section 13 is completed using an open hole method. However, in ultra-deep salt mines with complex geological conditions, high formation pressure, and many interlayers, open hole completion can easily lead to channel blockage in the horizontal section 13, causing the brine well to be unable to be put into production. The brine well casing 3 in the present application can be used for the completion of the horizontal section 13. The brine well casing 3 is set in the horizontal section 13, so that the flow channel of the brine well casing 3 serves as the connecting channel of the horizontal section 13. Since the pipe wall of the brine well casing 3 is provided with a through hole 34, the brine in the flow channel can pass through the through hole 34 into the salt mine outside the brine well casing 3 to dissolve the salt mine. The brine containing the salt mine partially flows outside the pipe wall to the brine outlet well 2, and partially re-enters the flow channel to flow to the brine outlet well 2. The through holes 34 provided on the wall of the well casing 3 can ensure the normal mining of the salt mine. At the same time, due to the existence of the brine well casing 3, the wall of the brine well casing 3 can support the horizontal section 13, thereby avoiding the blockage of the channel caused by factors such as formation instability and collapse, creep, irregular cavity morphology development, and migration and accumulation of insoluble matter, solving the problem of repeated blockage and inability to put into production in the past well group. Therefore, by using the brine well casing 3 in the horizontal section 13, the brine well structure can be smoothly put into production and the dissolution cavity construction of the deep well can be successfully completed. In addition, since the brine well casing 3 can support the horizontal section 13 and avoid the collapse and blockage of the horizontal section 13, the operating life of the well group can be extended. In addition, in the prior art, the connection point between the brine well 2 and the water injection well is also prone to blockage, and since the horizontal section 13 is completed in an open hole manner in the prior art, if the connection point is blocked, the horizontal section 13 is also prone to blockage. Therefore, it is necessary to unblock both the horizontal section 13 and the connection point, resulting in high well dredging costs. In the present application, a brine well casing 3 can be set in the horizontal section 13 to avoid blockage in the horizontal section 13. Even if the connection point is blocked, the horizontal section 13 can still be kept unobstructed and will not be blocked. Therefore, only the connection point needs to be unblocked, saving the well dredging costs of the horizontal well.

[0029] In addition, the brine well casing 3 is required to be uniform, smooth and burr-free. After drilling, the entire brine well casing 3 is subjected to anti-corrosion and anti-rust treatment to form a dense protective layer on the surface of the brine well casing 3, thereby improving the corrosion resistance and wear resistance of the brine well casing 3 and effectively extending its underground working life.

[0030] The purpose of the present invention and the solution to its technical problems can be further achieved by adopting the following technical measures.

[0031] Specifically, if Figure 2As shown, the brine well casing 3 includes a first end 31 and a second end 32 relative to each other, the first end 31 is connected to the brine well 2, and the second end 32 is far away from the brine well 2, and the arrangement density of the through holes 34 near the first end 31 is greater than the arrangement density of the through holes 34 near the second end 32.

[0032] Among them, the brine well casing 3 includes a first end 31 and a second end 32 relative to each other. The first end 31 is connected to the brine well 2. The connection point between the two can be located at the bottom of the brine well 2, which is not specifically limited here. The second end 32 is connected to the inclined section 12. When clean water is injected into the injection well, the water flows from the vertical well section 11 into the inclined section 12, and then enters the horizontal section 13. After entering the horizontal section 13, it first passes through the second end 32 of the brine well casing 3, and then passes through the first end 31 of the brine well casing 3 to enter the brine well 2. The arrangement density of the through-holes 34 in the area near the second end 32 of the brine well casing 3 is smaller than the arrangement density of the through-holes 34 near the first end 31. That is, the number of through-holes 34 provided per unit length in the area near the second end 32 is smaller than the number of through-holes 34 provided per unit length in the area near the first end 31. Therefore, the liquid flow rate entering the exterior of the brine well casing 3 from the area near the second end 32 is smaller, while the liquid flow rate entering the exterior of the brine well casing 3 from the area near the first end 31 is larger. The dissolution rate of salt ore is related to the brine content and volume of the brine in the brine. Brine flows from the second end 32 to the first end 31. When the clean water first enters the brine well casing 3, it does not contain brine, which makes the salt ore dissolve faster. After the clean water dissolves the brine, part of it flows directly into the brine outlet well 2 on the outside of the pipe wall, and part flows back into the flow channel. As the brine gradually flows toward the first end 31, the brine content in the liquid increases. As the brine content increases, the dissolution rate of the brine decreases. If the arrangement density of the through holes 34 in the area near the second end 32 is the same as the arrangement density of the through holes 34 in the area near the first end 31, then the volume of brine entering the salt mine at the first end 31 and the second end 32 is the same. Since the concentration of salt ore in the brine at the second end 32 is low and the concentration of salt ore in the brine near the first end 31 is high, the amount of salt ore dissolved near the second end 32 is higher than that at the second end 32 within the same period of time, that is, the dissolution rate of salt ore near the second end 32 is higher than that of salt ore near the first end 31.In the present application, the density of the through holes 34 in the area near the second end 32 of the brine well casing 3 is relatively low. Therefore, in the area near the second end 32, less clean water enters the salt mine, and the amount of dissolved brine is relatively small. After the clean water dissolves the brine, it enters the flow channel again. As the brine gradually flows to the first end 31, or directly flows to the first end 31 in the flow channel outside the brine well casing 3, the brine content in the brine in the flow channel will gradually increase. Therefore, in the area near the first end 31, the dissolution rate of the liquid for the salt mine is lower than that of the second end 32. However, due to the brine well casing 3 The arrangement density of the through holes 34 in the area near the first end 31 is relatively high. Therefore, a larger amount of liquid enters the salt mine in the area near the first end 31 of the brine well casing 3. At this time, although the dissolution rate of the liquid in the salt mine is relatively low, due to the large amount of liquid, more salt mines can be dissolved. In summary, in the area near the second end 32, the brine content in the brine is low, but the volume of the brine is relatively small, while in the area near the first end 31, the brine content in the brine is high, but the volume of the brine is large. Therefore, the dissolution rate of the salt mine near the first end 31 can be roughly consistent with the dissolution rate of the salt mine near the second end 32. Among them, in order to ensure that the arrangement density of the through holes 34 near the first end 31 of the brine well casing 3 is greater than the arrangement density of the through holes 34 at the second end 32, the arrangement density of the through holes 34 can be gradually increased along the direction from the second end 32 to the first end 31. Or along the direction from the second end 32 to the first end 31, the brine well casing 3 includes multiple areas, each area has a certain arrangement density of through holes 34, and the arrangement density of through holes 34 in the area close to the first end 31 is greater than the arrangement density of through holes 34 in the area close to the second end 32.

[0033] Specifically, the plurality of through holes 34 are arranged on the tube wall along a spiral line.

[0034] The through holes 34 are arranged in a spiral on the pipe wall, rather than being arranged along the axial direction of the brine well casing 3, so as to avoid significant damage to the strength of the brine well casing 3 caused by drilling. In order to ensure the number of through holes 34, the through holes 34 can be arranged not only along the same spiral line, but also along multiple spiral lines on the pipe wall.

[0035] Specifically, the phase angle between two adjacent via holes 34 located on the same spiral line is greater than or equal to 45° and less than or equal to 60°.

[0036] Among them, if the phase angle between two adjacent through holes 34 is too small, the strength of the brine well casing 3 will be low. Selecting a suitable phase angle can ensure that the brine well casing 3 has high strength, wherein the phase angle preferably ranges from greater than or equal to 45° to less than or equal to 60°. In order to ensure the strength of the brine well casing 3, the two adjacent rows of through holes 34 of the brine well casing 3 should be staggered. Furthermore, the two adjacent columns of through holes 34 can be staggered, wherein each row of through holes 34 is arranged along the circumferential direction of the brine well casing 3, and each column of through holes 34 is arranged along the longitudinal direction of the brine well casing 3.

[0037] Specifically, if Figure 2 and Figure 4 As shown, the brine well casing 3 also includes: a plurality of perforated pipes 33, the plurality of perforated pipes 33 are connected in sequence, a plurality of through holes 34 are arranged on the side walls of the perforated pipes 33, and the perforated pipes 33 include a third end 331 and a fourth end 332 relative to each other; a joint pipe 4, one end of the joint pipe 4 is used to be sleeved on the third end 331 of any of the perforated pipes 33, and the other end is used to be sleeved on the fourth end 332 of any other of the perforated pipes 33.

[0038] The brine well casing 3 is composed of a plurality of perforated pipes 33 connected in sequence. The perforated pipe 33 includes a side wall and a sub-channel surrounded by the side wall. The plurality of sub-channels are connected in sequence to form a flow channel. A through hole 34 is provided on the side wall of the perforated pipe 33. The joint pipe 4 is threadedly connected to the perforated pipe 33. Threads can be provided on the outer surfaces of the third end 331 and the fourth end 332 of the perforated pipe 33, and threads can be provided on the inner surface of the casing. Any two perforated pipes 33 can be fixed by a joint pipe 4. Connecting two adjacent perforated pipes 33 by a joint pipe 4 can ensure the connection strength of the joint. The diameter φ of the perforated pipe 33 is equal to 177.8 mm, the steel grade is P110; the wall thickness is 12.65 mm; and the inner diameter is 152.5 mm. The brine well casing 3 is composed of a plurality of perforated pipes 33 spliced ​​together, which is convenient for transportation and storage of the perforated pipes 33. Furthermore, the third end 331 of any perforated tube 33 can be sleeved onto the fourth end 332 of any other perforated tube 33. Specifically, threads are provided on the inner surface of the third end 331, and threads are provided on the outer surface of the fourth end 332. The outer diameter of the fourth section matches the inner diameter of the third end 331, so that the third end 331 of any perforated tube 33 can be sleeved onto the fourth end 332 of any other perforated tube 33 via threads. In order to prevent the perforated tube 33 from being too long and thus reducing its strength, the length of the perforated tube 33 can be set to 10 meters.

[0039] Specifically, if Figure 3As shown, the third end 331 of the perforated tube 33 is provided with a first fixed area 334, and the fourth end 332 is provided with a second fixed area 335. A hole distribution area 333 is formed between the first fixed area 334 and the second fixed area 335. A plurality of through holes 34 are provided in the hole distribution area 333. One end of the connecting tube 4 is used to be sleeved on a part of the first fixed area 334 of any perforated tube 33, and the other end is used to be sleeved on a part of the second fixed area 335 of any other perforated tube 33.

[0040] Part of the outer surface of the first fixing area 334 is provided with threads, and part of the outer surface of the second fixing area 335 is provided with threads. Figure 2 As shown, the joint pipe 4 can be sleeved only on a portion of the first fixing area 334 and a portion of the second fixing area 335, with the through holes 34 provided only in the hole arrangement area 333. This avoids locating the threads and through holes 34 in the same area, which could reduce the strength of the brine well casing 3. Furthermore, the first fixing area 334 and the second fixing area 335 that are not sleeved on the joint pipe 4 are not provided with through holes 34. That is, a first distance L is defined between the joint pipe 4 and the nearest through hole 34. The first distance L is greater than or equal to 400 mm and less than or equal to 500 mm.

[0041] Specifically, the total area of ​​the plurality of through holes 34 is less than or equal to 90% of the side wall area of ​​the perforated tube 33 .

[0042] In order to ensure the strength of the perforated tube 33 , the total area of ​​the through holes 34 should be less than or equal to 90% of the area of ​​the side wall of the perforated tube 33 .

[0043] Specifically, a first region and a second region are sequentially provided between the first end 31 and the second end 32 , and an arrangement density of the vias 34 provided in the second region is smaller than an arrangement density of the vias 34 provided in the first region.

[0044] The first area and the second area can be formed on different perforated tubes 33, wherein the arrangement density of the through holes 34 in the second area is 15 to 45 through holes 34 per meter, which are arranged on the second perforated tube 33b, and the arrangement density of the through holes 34 in the first area can be 60 to 100 through holes 34 per meter, which are arranged on the first perforated tube 33a. Figure 2As shown, in order to avoid the length of a single brine well casing 3 being too long, which would result in unreliable strength of the brine well casing 3, multiple perforated pipes 33 are used to form the brine well casing 3, with the first perforated pipe 33a being arranged near the first end 31, and the second perforated pipe 33b being arranged near the second end 32. The hole arrangement density of the first perforated pipe 33a is greater than the hole arrangement density of the second perforated pipe 33b, and the number of 33a and 33b can be set as required, that is, the brine well casing 3 includes multiple first perforated pipes 33a and multiple second perforated pipes 33b. Figure 2 As shown, a first perforated tube 33a near the first end 31 and a second perforated tube 33b near the second end 32 are provided with multiple perforated tubes 33, and the perforated tubes 33 between the two are omitted. Typically, the horizontal section 13 requires a brine well casing 3 of 80 meters in length, each perforated tube 33 is 10 meters long, and the perforated area 333 on each perforated tube 33 occupies 9 meters, while the first fixed area 334 and the second fixed area 335 each occupy 0.5 meters. In this case, two second perforated tubes 33b and six first perforated tubes 33a can be sequentially arranged between the second end 32 and the first end 31. The arrangement density of the through holes 34 in the second area is preferably 15 through holes 34 per meter, while the arrangement density of the through holes 34 in the first area is preferably 80 through holes 34 per meter. A third region to an Nth region may be formed between the first end 31 and the second end 32 , each region having a different via 34 arrangement density, but it is necessary to ensure that the via arrangement density in the region near the second end 32 is less than the via arrangement density in the region near the first end 31 .

[0045] In another aspect, an embodiment of the present invention further provides a brine production well structure, comprising: an injection well comprising a vertical well section 11, a deflection section 12, and a horizontal section 13 connected in sequence; a brine outlet well 2 connected to the end of the horizontal section 13 facing away from the deflection section 12; and a brine production well casing 3 as described in any of the above. Therefore, this embodiment has all the beneficial effects of the brine production well casing 3 provided in any of the above embodiments, and further description thereof is omitted.

[0046] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A brine well casing, used for a brine well structure, the brine well structure comprising: The water injection well comprises: a vertical well section, a deflection section and a horizontal section connected in sequence; a brine production well is connected to the end of the horizontal section away from the deflection section; and the brine production well casing comprises: A pipe wall and a flow channel enclosed by the pipe wall, wherein the pipe wall is formed with a plurality of through holes connected to the flow channel, the brine well casing is used to be arranged in the horizontal section of the water injection well, and the flow channel is used to form a connecting channel in the horizontal section; The device comprises a first end and a second end opposite to each other, wherein the first end is connected to the brine outlet well, and the second end is away from the brine outlet well, wherein the arrangement density of the via holes near the first end is greater than the arrangement density of the via holes near the second end, and the number of the via holes arranged per unit length in an area near the second end is less than the number of the via holes arranged per unit length in an area near the first end; A plurality of via holes are arranged on the tube wall along a spiral line.

2. The brine well casing according to claim 1, characterized in that: The phase angle between two adjacent via holes located on the same spiral line is greater than or equal to 45° and less than or equal to 60°.

3. The brine well casing according to claim 1, characterized in that: The brine well casing comprises: a plurality of perforated pipes, the plurality of perforated pipes are connected in sequence, a plurality of through holes are provided on the side walls of the perforated pipes, and the perforated pipes include a third end and a fourth end opposite to each other; A joint pipe, one end of which is used to be sleeved on the third end of any of the perforated pipes, and the other end of which is used to be sleeved on the fourth end of any other of the perforated pipes.

4. The brine well casing according to claim 3, characterized in that: The third end of the perforated tube is provided with a first fixing area, and the fourth end is provided with a second fixing area. A hole distribution area is formed between the first fixing area and the second fixing area, and multiple through holes are provided in the hole distribution area. One end of the joint tube is used to be sleeved on part of the first fixing area of ​​any perforated tube, and the other end is used to be sleeved on part of the second fixing area of ​​any other perforated tube.

5. The brine well casing according to claim 3, characterized in that: The total area of ​​the plurality of via holes is less than or equal to 90% of the side wall area of ​​the perforated tube.

6. The brine well casing according to claim 1, characterized in that: A first region and a second region are sequentially arranged between the first end and the second end, and an arrangement density of the via holes arranged in the second region is smaller than an arrangement density of the via holes arranged in the first region.

7. A brine well structure, characterized in that: include: The water injection well includes: a vertical well section, a deflection section and a horizontal section connected in sequence; a brine outlet well connected to an end of the horizontal section away from the deflection section; And the brine well casing according to any one of claims 1 to 6.

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