Pressure-resistant sand filtering pipe

Abstract

The utility model discloses a pressure-resistant sand filtering pipe which comprises a coupling and a base pipe, an upper filtering section and a lower filtering section are sequentially arranged on the outer wall of the base pipe from top to bottom, and a plurality of overflowing holes are formed in the positions, corresponding to the upper filtering section and the lower filtering section, of the pipe wall of the base pipe. A flow equalizing cylinder, a fine sand filter screen cylinder, a coarse sand filter screen cylinder and an outer protective cylinder are sequentially arranged on the outer circumference of the base pipe of the upper filtering section from inside to outside, a flow equalizing cylinder, a fine sand filter screen cylinder, a coarse sand filter screen cylinder, a wire winding filter cylinder and an outer protective cylinder are sequentially arranged on the outer circumference of the base pipe of the lower filtering section from inside to outside, and a plurality of flow equalizing holes are evenly distributed in the cylinder wall of the flow equalizing cylinder. The diameter of each flow equalizing hole is smaller than a half of the diameter of each flow passing hole, and the number of the flow equalizing holes is not smaller than four times of the number of the flow passing holes in the base tube corresponding to the flow equalizing cylinder. When the sand filtering pipe works, oil liquid is good in distribution uniformity on the filter screen, sand accumulation blocking points are not easy to form on the filter screen near the overflowing holes of the base pipe, the filter screen is not easy to deform, and the sand filtering pipe can bear large filtering pressure difference.

Description

Technical Field

[0001] The utility model relates to an oilfield underground sand prevention device, in particular to a sand filter pipe suitable for heavy oil wells with a large sand content. Background Art

[0002] Sand-producing oil wells require downhole sand filters to prevent sand from entering the oil well pump. When operating in heavy oil wells, the high viscosity of the oil results in a significant pressure differential between the inside and outside of the filter. This is especially true when sand accumulates on the filter screen surface, reducing the effective flux of the filter and further increasing the pressure differential. When the pressure differential exceeds the filter's tolerance limit, the filter can be damaged, losing its sand control effectiveness, accelerating wear on the oil well pump and tubing, and even rendering the oil well pump useless. CN 201924900 U discloses a high-strength composite sand filter pipe, which includes a coupling, a base pipe, an upper baffle ring, an outer protective pipe, a filter screen, and a lower baffle ring. The base pipe is provided with a connecting hole, the coupling is connected to the base pipe, the outer protective pipe is sleeved outside the filter screen, the upper ends of the outer protective pipe and the filter screen are welded to the upper baffle ring, the lower ends of the outer protective pipe and the filter screen are welded to the lower baffle ring, the upper baffle ring is welded to the upper part of the base pipe, and the lower baffle ring is welded to the lower part of the base pipe. A stainless steel wire wrapping pipe is installed between the filter screen and the base pipe, the upper end of the stainless steel wire wrapping pipe is welded to the upper baffle ring, and the lower end of the stainless steel wire wrapping pipe is welded to the lower baffle ring. After the stainless steel wire wrapping pipe is installed between the filter screen and the base pipe, liquid flows in evenly, which is beneficial to protecting the filter screen. The stainless steel wire wrapping pipe has high strength and can both block sand and protect the filter screen from damage. However, during the operation of this type of sand filter tube, the oil flow rate near the connecting hole of the base pipe is relatively fast, which will cause the filter screen near the connecting hole of the base pipe to be clogged with sand first, forming an early sand accumulation blockage. Once the sand accumulation blockage is formed, it will gradually spread, thereby increasing the pressure difference on both sides of the filter screen. Since the length of the filter screen in the axial direction of the base pipe is usually 2 to 3 meters and there is a lack of rigid support in the middle, this will cause the filter screen to collapse and deform, stick to the base pipe, and then block the connecting hole on the base pipe, causing the sand filter tube to be scrapped. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a pressure-resistant sand filter tube. When the sand filter tube is working, the oil is evenly distributed on the filter screen, it is not easy to form sand accumulation blockages on the filter screen near the flow hole of the base pipe, the filter screen is not easy to deform, and the sand filter tube can withstand a large filtration pressure difference.

[0004] The technical solution adopted to solve the technical problem: A pressure-resistant sand filter pipe, including a coupling and a base pipe, an upper filter section and a lower filter section are provided on the outer wall of the base pipe from top to bottom, and a plurality of flow holes are opened on the base pipe wall corresponding to the upper filter section and the lower filter section, and a flow equalizing cylinder, a fine sand filter screen cylinder, a coarse sand filter screen cylinder and an outer casing are provided on the outer circumference of the base pipe of the upper filter section from the inside to the outside, and a flow equalizing cylinder, a fine sand filter screen cylinder, a coarse sand filter screen cylinder, a wire-wound filter cylinder and an outer casing are provided on the outer circumference of the base pipe of the lower filter section from the inside to the outside, and a plurality of flow equalizing holes are evenly distributed on the wall of the flow equalizing cylinder, the diameter of the flow equalizing hole is less than half of the diameter of the flow hole, and the number of the flow equalizing holes is not less than 4 times the number of flow holes on the base pipe corresponding to the flow equalizing cylinder.

[0005] As a further improvement of the present invention: the wire-wound filter cartridge includes a plurality of axial support ribs in a circumferential array, and a trapezoidal cross-section wire wound around the plurality of axial support ribs, thereby forming a spiral sand filter seam with a trapezoidal cross-section that is larger inside and smaller outside on the wire-wound filter cartridge.

[0006] As a further improvement of the present invention: in the trapezoidal cross-section of the wire winding, the height of the trapezoid is greater than the length of the lower base of the trapezoid.

[0007] As a further improvement of the present invention, a plurality of spirally arranged axial strip-shaped liquid inlets are provided on the wall of the outer casing.

[0008] As a further improvement of the present invention, a flow cavity with an annular cross-section is left between the flow balancing cylinder and the fine sand filter cylinder.

[0009] As a further improvement of the present invention, a plurality of inner supporting protrusions convex toward the base pipe and a plurality of outer supporting protrusions convex toward the fine sand filter cylinder are evenly distributed on the cylinder wall of the flow equalizing cylinder.

[0010] As a further improvement of the present invention: an inner end ring and an outer end ring are welded to the outer walls of the base pipe at both ends of the upper filter section, and the two ends of the outer casing are fixed to the outer walls of the base pipe at both ends of the upper filter section through the outer end rings, and the two ends of the flow equalizing tube, the fine sand filter screen tube, and the coarse sand filter screen tube are respectively fixed to the outer walls of the base pipe at both ends of the upper filter section through the inner end rings.

[0011] As a further improvement scheme of the present utility model: an inner end ring and an outer end ring are welded to the outer wall of the base pipe at both ends of the lower filter section, and the two ends of the outer casing are fixed to the outer wall of the base pipe at both ends of the lower filter section through the outer end rings, and the two ends of the flow equalizing cylinder, fine sand filter screen cylinder, coarse sand filter screen cylinder, and wire-wound filter cylinder are respectively fixed to the outer wall of the base pipe at both ends of the lower filter section through the inner end rings.

[0012] Beneficial effects: The pressure-resistant sand filter tube of the utility model adopts the technical feature that an upper filter section and a lower filter section are sequentially provided on the outer wall of the base pipe from top to bottom. By setting the two filter sections, the length of the filter screens in the fine sand filter cylinder and the coarse sand filter cylinder in the axial direction of the base pipe can be effectively shortened, so that the filter screen has stronger deformation resistance, so that the filter screen can withstand higher pressure differences without deformation, and avoid the filter screen sticking to the base pipe and blocking the flow holes; since a flow equalizing cylinder is provided on the outer circumference of the base pipe, and the diameter and number ratio of the flow equalizing holes to the flow holes is limited, the uniformity of the distribution of oil on the filter screen surface is better, and the disadvantage of excessive local flow velocity of the oil screen near the flow holes of the base pipe, resulting in sand accumulation and blockage, which accelerates the failure of the sand filter tube can be effectively avoided. Therefore, the pressure-resistant sand filter tube of the utility model has a long service life, can withstand higher filtration pressure differences, and can meet the sand control requirements of sand-producing heavy oil wells. In addition, by setting up a wire-wound filter cartridge only in the lower filter section, full use is made of the natural sedimentation of sand particles in the oil, resulting in less sand in the oil in the upper filter section and higher sand in the oil in the lower filter section. While increasing the sand prevention effect of the lower filter section, the filtration resistance of the upper filter section is not increased, which is conducive to the oil with less sand content passing through the upper filter section with better permeability, thereby further extending the service life of the sand filter tube. Due to the technical feature that the wire-wound filter cartridge includes a plurality of axial support ribs in a circumferential array and a trapezoidal cross-section wire wound around the plurality of axial support ribs, a spiral sand filter slit with a trapezoidal cross-section that is larger inside and smaller outside is formed on the wire-wound filter cartridge. On the one hand, the oil can be evenly distributed onto the filter screen through the spiral sand filter slit. On the other hand, the spiral sand filter slit allows the sand particles stuck in the slit to move slightly along the spiral direction of the spiral sand filter slit under the continuous flushing of the oil and the action of gravity. During the movement, some of the sand particles can be crushed or fall off the spiral sand filter slit, preventing the sand particles from getting stuck in the wire-wound filter cartridge, thereby having an automatic sand removal function. Due to the technical feature that the height of the trapezoidal cross-section of the wire is greater than the length of the lower base of the trapezoid, the wire-wound filter cartridge is not easily deformed by pressure and can withstand a larger filtration pressure difference, further improving the pressure-bearing capacity of the pressure-resistant sand filter tube of the present invention. Due to the technical feature of multiple spirally arranged axial strip inlets on the wall of the outer casing, these axial strip inlets are arranged approximately perpendicular to the spiral sand filter slits, one vertically and one horizontally, allowing oil to enter the coarse sand filter cylinder from all angles, and the oil is more evenly distributed on the filter surface. Due to the technical feature of leaving a flow chamber with an annular cross-section between the flow equalizing cylinder and the fine sand filter cylinder, the oil filtered by the fine sand filter cylinder is buffered in the flow chamber before entering the flow equalizing cylinder, preventing sand particles from accumulating near the flow equalizing holes. Due to the technical feature of multiple internal support protrusions protruding toward the base pipe and multiple external support protrusions protruding toward the fine sand filter cylinder evenly distributed on the wall of the flow equalizing cylinder, it can prevent the fine sand filter cylinder from fitting against the flow equalizing cylinder, and vice versa, when the filtration pressure difference is large.Due to the technical features of welding an inner end ring and an outer end ring on the outer wall of the base pipe at both ends of the upper filter section, and welding an inner end ring and an outer end ring on the outer wall of the base pipe at both ends of the lower filter section, the flow equalizing cylinder, fine sand filter cylinder, coarse sand filter cylinder, and wire-wound filter cylinder are fixed more conveniently and firmly. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The pressure-resistant sand filter tube of the present invention will be described in further detail below with reference to the accompanying drawings.

[0014] Figure 1 This is a schematic diagram of the overall structure of the pressure-resistant sand filter pipe of the utility model;

[0015] Figure 2 It is a partial enlarged view of the wire-wound filter cartridge in the pressure-resistant sand filter tube of the present invention. DETAILED DESCRIPTION

[0016] like Figure 1 As shown, the pressure-resistant sand filter pipe of the present invention includes a coupling 1 and a base pipe 8. An upper filter section a and a lower filter section b are provided on the outer wall of the base pipe in sequence from top to bottom. A plurality of flow holes 81 are opened on the base pipe walls corresponding to the upper filter section and the lower filter section. A flow equalizing cylinder 7, a fine sand filter screen cylinder 6, a coarse sand filter screen cylinder 5 and an outer casing 4 are provided on the outer circumference of the base pipe of the upper filter section in sequence from inside to outside. A flow equalizing cylinder, a fine sand filter screen cylinder, a coarse sand filter screen cylinder, a wire-wound filter cylinder 9 and an outer casing are provided on the outer circumference of the base pipe of the lower filter section in sequence from inside to outside. A flow cavity 10 with an annular cross-section is left between the flow equalizing cylinder and the fine sand filter screen cylinder, and a plurality of spirally arranged axial strip liquid inlets 41 are opened on the wall of the outer casing. An inner end ring 3 and an outer end ring 2 are welded to the outer wall of the base pipe at both ends of the upper filter section. The outer end rings secure the ends of the outer casing to the outer wall of the base pipe at both ends of the upper filter section. The inner end rings secure the ends of the flow equalizer, fine sand filter, and coarse sand filter to the outer wall of the base pipe at both ends of the upper filter section. An inner end ring and an outer end ring are welded to the outer wall of the base pipe at both ends of the lower filter section. The outer end rings secure the ends of the outer casing to the outer wall of the base pipe at both ends of the lower filter section. The inner end rings secure the ends of the flow equalizer, fine sand filter, coarse sand filter, and wire-wound filter to the outer wall of the base pipe at both ends of the lower filter section.

[0017] like Figure 2 As shown, the wire-wound filter cartridge includes a plurality of axial support ribs 93 arranged in a circular array with the center of the base pipe as the center, and a trapezoidal cross-section wire 91 wound around the plurality of axial support ribs, thereby forming a spiral sand filter slit 92 with a trapezoidal cross-section that is larger inside and smaller outside on the wire-wound filter cartridge. In the trapezoidal cross-section of the wire, the height of the trapezoid is greater than the length of the lower base of the trapezoid, where the lower base refers to the longer bottom side of the trapezoid. Figure 2The trapezoidal side near the outer casing is the lower base 94. Multiple flow holes 71 are evenly distributed on the wall of the flow equalizing tube. Multiple inner support protrusions 73 protruding toward the base pipe and multiple outer support protrusions 72 protruding toward the fine sand filter tube are also evenly distributed on the wall of the flow equalizing tube.

[0018] Preferably, the diameter of the flow balancing hole is less than half of the diameter of the flow-through hole, and the number of the flow balancing holes is not less than 4 times the number of the flow-through holes of the base tube corresponding to the flow balancing cylinder.

Claims

1. A pressure-resistant sand filter pipe, comprising a coupling and a base pipe, characterized by: An upper filter section and a lower filter section are sequentially provided on the outer wall of the base pipe from top to bottom, and a plurality of flow holes are opened on the base pipe walls corresponding to the upper filter section and the lower filter section. A flow equalizing cylinder, a fine sand filter screen cylinder, a coarse sand filter screen cylinder and an outer casing are sequentially provided on the outer circumference of the base pipe of the upper filter section from inside to outside. A flow equalizing cylinder, a fine sand filter screen cylinder, a coarse sand filter screen cylinder, a wire-wound filter cylinder and an outer casing are sequentially provided on the outer circumference of the base pipe of the lower filter section from inside to outside. A plurality of flow equalizing holes are evenly distributed on the wall of the flow equalizing cylinder. The diameter of the flow equalizing hole is less than half of the diameter of the flow hole, and the number of the flow equalizing holes is not less than 4 times the number of flow holes on the base pipe corresponding to the flow equalizing cylinder.

2. The pressure-resistant sand filter pipe according to claim 1, characterized in that: The wire wound filter cartridge includes a plurality of axial support ribs in a circumferential array and a trapezoidal cross-section wire wound outside the plurality of axial support ribs, thereby forming a spiral sand filter seam with a trapezoidal cross-section that is larger inside and smaller outside on the wire wound filter cartridge.

3. The pressure-resistant sand filter pipe according to claim 2, characterized in that: In the trapezoidal cross-section of the wire winding, the height of the trapezoid is greater than the length of the lower base of the trapezoid.

4. The pressure-resistant sand filter pipe according to claim 3, characterized in that: A plurality of spirally arranged axial strip-shaped liquid inlets are provided on the wall of the outer casing.

5. The pressure-resistant sand filter pipe according to any one of claims 1 to 4, characterized in that: A flow cavity with an annular cross-section is reserved between the flow equalizing cylinder and the fine sand filter cylinder.

6. The pressure-resistant sand filter pipe according to claim 5 is characterized in that: A plurality of inner supporting protrusions convex toward the base pipe and a plurality of outer supporting protrusions convex toward the fine sand filter cylinder are evenly distributed on the cylinder wall of the flow equalizing cylinder.

7. The pressure-resistant sand filter pipe according to claim 6 is characterized in that: An inner end ring and an outer end ring are welded to the outer walls of the base pipe at both ends of the upper filter section. The two ends of the outer casing are fixed to the outer walls of the base pipe at both ends of the upper filter section through the outer end rings. The two ends of the flow equalizing cylinder, fine sand filter cylinder, and coarse sand filter cylinder are respectively fixed to the outer walls of the base pipe at both ends of the upper filter section through the inner end rings.

8. The pressure-resistant sand filter pipe according to claim 7, characterized in that: An inner end ring and an outer end ring are welded to the outer wall of the base pipe at both ends of the lower filter section. The two ends of the outer casing are fixed to the outer wall of the base pipe at both ends of the lower filter section through the outer end rings. The two ends of the flow equalizing cylinder, fine sand filter cylinder, coarse sand filter cylinder, and wire-wound filter cylinder are respectively fixed to the outer wall of the base pipe at both ends of the lower filter section through the inner end rings.

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