Sand filter screen for underground oil production

Abstract

The invention discloses a sand filter pipe for downhole oil production and relates to the technical field of sand filter pipes. In the invention, as hydraulic oil is continuously injected, an outer sand filter pipe column continues to retract inwardly and an inner sand filter pipe column continues to expand outwardly, and the alternation of the inner and outer positions of the outer sand filter pipe column and the inner sand filter pipe column is satisfied by elastic deformation after extrusion between the outer flexible outer coverings of the outer sand filter pipe column and the inner sand filter pipe column, that is, the outer sand filter pipe column will change from the outside to the inside, and the inner sand filter pipe column will change from the inside to the outside. During this period, a large amount of sand and gravel originally blocked in the sand filter gap between the outer sand filter pipe column and the inner sand filter pipe column will be returned to the outside of the sand filter pipe and returned to the formation, so as to achieve the effect of rapid unblocking, and there is no need to take out the entire mining system and dismantle the sand filter pipe for cleaning and unblocking as in the traditional way, which saves time and effort.

Description

Technical Field

[0001] The invention relates to the technical field of sand filter screen pipes, in particular to a sand filter screen pipe for downhole oil production. Background Art

[0002] Oil well sand filter screens are often used in various industries, and their position in the water treatment industry is particularly prominent. They are one of the most widely used types of water resource and collection resin filter screens. Their main characteristics include multi-layer sand control filter sets with high-efficiency sand control performance, which can better block formation sand particles and meet the needs of underground sand control. The filter holes are uniform, the permeability and anti-blocking performance are high, the filtration area is large, the flow resistance is small, the oil yield is high, and the stainless steel material has excellent corrosion resistance.

[0003] There is a problem when using underground sand filter screens, that is, it is inconvenient to dismantle and clean. For this reason, the Chinese patent with publication number CN212614650U proposes an easy-to-clean sand filter screen for oil production. The user can quickly assemble the sand filter screen for installation and use when needed, and the user can regularly dismantle and clean it, and separate the sand filter tube shell, tube head and filter screen from each other, to ensure that the cleaning is more comprehensive and thorough.

[0004] In fact, the problems in cleaning the sand filter screen for underground oil production include but are not limited to the above one, as follows:

[0005] At present, the sand filter screens used in the industry are all porous sand filter structures. The existing sand filter screen apertures cannot be adaptively changed. In fact, the sand content, sand particle size distribution, and fineness of gravel in the downhole environment fluid are not constant. There may be more coarse sand in a certain period of time, and more fine sand in the next period of time. Therefore, generally, only a relatively suitable aperture can be configured according to the geological conditions to meet basic needs. In fact, the smaller the aperture, the greater the resistance to the fluid, and the greater the impact on the oil production rate. A large aperture will allow some small fine gravel to pass through in certain periods of time, which affects the quality of the oil. Therefore, there has always been a contradictory influence between the aperture of the filter hole and the oil production efficiency. At present, it is difficult for the sand filter screen to achieve a balance between the two. Therefore, changing the appropriate aperture at the right time is the key issue to maximize the oil production efficiency and ensure accurate sand filtering to prevent fine sand from invading the mining system.

[0006] The purpose of being removable is to facilitate the cleaning of the filter element of the sand filter screen, but in fact the sand filter screen has to be taken out of the oil well for cleaning, and the sand filter screen is generally located at the bottom of the oil well. Cleaning the sand filter screen means that the entire production system needs to be taken out before the sand filter tube can be cleaned. If the sand filter screen is severely clogged during oil production, the only way to deal with it is to terminate the operation and take out the sand filter screen, which is time-consuming and laborious.

[0007] Therefore, the inventor, relying on his many years of experience and practice in related industries, proposes an "elastic" sand filter screen that can automatically unblock without being taken out, so as to overcome the defects of the prior art. Summary of the invention

[0008] The technical solution of the present invention aims at the technical problem that the existing technical solutions are too single, and provides a solution that is significantly different from the existing technologies. Specifically, the purpose of the present invention is to provide a sand filter screen for downhole oil production, so as to solve the problem that the aperture of the existing sand filter screen cannot be adaptively changed. In fact, the sand content, sand particle size distribution, and fineness of gravel in the downhole environmental fluid are not constant. There may be more coarse sand in a certain period of time, and more fine sand in the next period of time. Therefore, generally, only a relatively suitable aperture can be configured according to the geological conditions to meet basic needs. In fact, the smaller the aperture, the greater the resistance to the fluid, and the greater the impact on the oil production rate. A large aperture will allow some small-fine gravel to pass through in certain periods of time, resulting in the quality of the oil being affected. Therefore, there has always been a contradictory influence between the aperture of the filter hole and the oil production efficiency. It is currently difficult for sand filter screens to achieve a balance between the two.

[0009] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a sand filter screen for downhole oil production, comprising a ring base and an upper ring cover, and an outer sand filter pipe column and an inner sand filter pipe column that are distributed at equal angles between the ring base and the upper ring cover and utilize sand filtering through adjacent gaps, a central tube for adjusting the centrifugal distance of the outer sand filter pipe column and the inner sand filter pipe column is arranged at the center of the ring base and the upper ring cover, and an oil pipeline for controlling the oil volume is connected through the interior of the central tube.

[0010] Preferably, the opposite surfaces of the ring base and the upper ring cover are provided with annular grooves for limiting the outer sand filter pipe column and the inner sand filter pipe column, the outer sand filter pipe column and the inner sand filter pipe column are alternately distributed at equal angles, and the inner sand filter pipe column is located on the inner side of the outer sand filter pipe column.

[0011] Preferably, the outer sand filter pipe column and the inner sand filter pipe column are both composed of an internal hard column core and a wear-resistant flexible outer cladding, and a gap for filtering is reserved between the outer sand filter pipe column and the inner sand filter pipe column.

[0012] Preferably, the outer sand filter tube column and the inner sand filter tube column at each angle corresponding to the ring base and the upper ring cover are respectively fixed with a first fixing plate and a second fixing plate at equal angles, and the outer walls of the outer sand filter tube column and the inner sand filter tube column are respectively fixed with a pull rod and a push rod, and the pull rod and the push rod respectively slide through the corresponding first fixing plate and the second fixing plate.

[0013] Preferably, a sealing oil chamber is opened at the center of the central tube, a first sealing rubber ring is arranged at the center of the sealing oil chamber, and the inner end of the pull rod is fixed to the outer wall of the first sealing rubber ring;

[0014] Second sealing rubber rings are symmetrically arranged at both ends of the sealing oil chamber, and the inner end of the push rod is fixed to the outer wall of the second sealing rubber ring.

[0015] Preferably, an oil cylinder is fixed at the center of the sealed oil chamber, and a piston is symmetrically installed inside the oil cylinder, and one end of the piston passes through the oil cylinder and is connected to a sealing disk that seals and separates the two sides of the oil cylinder. An oil guide pipe and a balance strut are symmetrically installed in the central area of ​​the oil cylinder, and the oil delivery pipe is connected to one end of the oil guide pipe.

[0016] Preferably, the other end of the oil guide pipe is connected to the central area of ​​the oil cylinder, and the two pistons are respectively connected to the oil guide pipe and the balance support in a through-type sliding manner.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The oil injection and pressure increasing equipment on the well can be used to inject oil and pressurize the inside of the oil pipeline. The hydraulic oil entering the oil pipeline will be input into the middle space of the oil cylinder through the two oil guide pipes on the top. As the hydraulic oil increases, the pressure inside the oil cylinder gradually increases, which will push outward the pistons symmetrically arranged on both sides, so that the two pistons will expand synchronously and symmetrically in opposite directions. The outer ends of the sealing plates of the two pistons will block the sealed oil chamber into three sealing areas. When the two pistons expand outward, the hydraulic oil inside the sealing areas on both sides will have a comprehensive outward pushing effect on the second sealing rubber rings on both sides, so that the two second sealing rubber rings at the upper and lower ends will bulge outward synchronously and push outward the inner sand filter pipe column synchronously through the push rods fixedly connected thereto. At the same time, as the negative pressure gradually generates as the pistons on both sides move away from the central area of ​​the sealed oil chamber, suction will be generated on the first sealing rubber ring located at the center to approach the center, so that the first sealing rubber ring will gradually concave and The pull rods distributed around are pulled synchronously, and the pull rods will pull the outer sand filter pipe column inward synchronously. At this time, the outer sand filter pipe column distributed at equal angles on the outside gradually retracts inward, while the inner sand filter pipe column distributed at equal angles on the inside gradually expands outward. The effect achieved is that the sand filter gap between the outer sand filter pipe column and the inner sand filter pipe column gradually narrows, so that finer sand and gravel can be screened out, so that the staff can judge whether it is necessary to narrow the sand filter gap to screen out finer sand and gravel according to the oil quality on the well, so as to achieve the effect of adjusting the sand filter gap anytime and anywhere without interrupting production. Similarly, the sand filter gap can be enlarged by pumping oil outward through the well equipment. When the oil quality is good, the sand filter gap can be appropriately increased to reduce the flow resistance to increase the oil output rate. At the same time, when the oil quality is poor and contains some fine sand and gravel, the sand filter gap needs to be appropriately narrowed to improve the sand filter quality and effect;

[0019] 2. In addition, a further effect is: when the oil output rate is greatly reduced during oil production, that is, when the filter sand gap is blocked by dense gravel, oil is still injected into the oil pipeline through the oil injection equipment on the well. Similarly, the outer sand filter pipe column retracts inwards, while the inner sand filter pipe column expands outwards. When the outer sand filter pipe column retracts inwards and the inner sand filter pipe column expands outwards to a certain extent, the flexible outer sheath of the outer sand filter pipe column and the flexible outer sheath of the inner sand filter pipe column gradually contact, causing the sand filter pipe to temporarily lose its sand filtering ability. With the continuous injection of hydraulic oil, the outer sand filter pipe column continues to retract inwards and the inner sand filter pipe column continues to retract. The pipe string continues to expand outward, and the alternation of the inside and outside positions of the outer sand filter pipe string and the inner sand filter pipe string is satisfied by the elastic deformation after squeezing between the external flexible outer coverings of the outer sand filter pipe string and the inner sand filter pipe string. That is to say, the outer sand filter pipe string will change from the outside to the inside, and the inner sand filter pipe string will change from the inside to the outside. During this period, a large amount of sand and gravel originally blocked in the sand filter gap between the outer sand filter pipe string and the inner sand filter pipe column will be returned to the outside of the sand filter pipe and returned to the formation, thereby achieving the effect of rapid unblocking. There is no need to take out the entire mining system and dismantle the sand filter pipe for cleaning and unblocking as in the traditional way, which saves time and effort. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a first stereoscopic schematic diagram of the present invention;

[0021] Figure 2 It is a second stereoscopic schematic diagram of the present invention;

[0022] Figure 3 It is a cross-sectional view of the present invention;

[0023] Figure 4 It is a schematic diagram of the front cross-sectional structure of the present invention;

[0024] Figure 5 It is a schematic diagram of a top-view cross-sectional structure of the present invention;

[0025] Figure 6 For the present invention Figure 4 Enlarged schematic diagram of the central tube.

[0026] In the figure: 1. ring base; 2. upper ring cover; 3. outer sand filter pipe column; 31. pull rod; 32. first fixed plate; 4. inner sand filter pipe column; 41. push rod; 42. second fixed plate; 5. center pipe; 51. sealed oil chamber; 52. oil cylinder; 53. piston; 54. oil guide pipe; 55. balance support; 6. first sealing rubber ring; 7. second sealing rubber ring; 8. oil pipeline. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] See also Figure 1-6 The present invention provides a technical solution: a sand filter screen for downhole oil production, comprising a ring base 1 and an upper ring cover 2, and an outer sand filter pipe column 3 and an inner sand filter pipe column 4 which are distributed at equal angles between the ring base 1 and the upper ring cover 2 and filter sand through adjacent gaps. A central pipe 5 for adjusting the centrifugal distance of the outer sand filter pipe column 3 and the inner sand filter pipe column 4 is arranged at the center of the ring base 1 and the upper ring cover 2, and an oil pipeline 8 for controlling the oil volume is connected through the interior of the central pipe 5.

[0029] The opposite surfaces of the ring base 1 and the upper ring cover 2 are provided with annular grooves for limiting the outer sand filter pipe column 3 and the inner sand filter pipe column 4. The outer sand filter pipe column 3 and the inner sand filter pipe column 4 are alternately distributed at equal angles, and the inner sand filter pipe column 4 is located on the inner side of the outer sand filter pipe column 3.

[0030] The outer sand filter pipe column 3 and the inner sand filter pipe column 4 are both composed of an inner hard column core and a wear-resistant flexible outer cladding, and a gap for filtering is reserved between the outer sand filter pipe column 3 and the inner sand filter pipe column 4 .

[0031] A first fixing plate 32 and a second fixing plate 42 are fixed at equal angles to the outer sand filter pipe column 3 and the inner sand filter pipe column 4 at each angle between the ring base 1 and the upper ring cover 2, and a pull rod 31 and a push rod 41 are fixed to the outer walls of the outer sand filter pipe column 3 and the inner sand filter pipe column 4, respectively, and the pull rod 31 and the push rod 41 slide through the corresponding first fixing plate 32 and the second fixing plate 42 respectively.

[0032] A sealing oil chamber 51 is opened at the center of the center tube 5, and a first sealing rubber ring 6 is arranged at the center of the sealing oil chamber 51, and the inner end of the pull rod 31 is fixed to the outer wall of the first sealing rubber ring 6;

[0033] Second sealing rubber rings 7 are symmetrically arranged at both ends of the sealing oil chamber 51 , and the inner end of the push rod 41 is fixed to the outer wall of the second sealing rubber ring 7 .

[0034] An oil cylinder 52 is fixed at the center of the sealed oil chamber 51, and a piston 53 is symmetrically installed inside the oil cylinder 52, and one end of the piston 53 passes through the oil cylinder 52 and is connected to a sealing disk that seals and separates the two sides of the oil cylinder 52. An oil guide pipe 54 and a balance strut 55 are symmetrically installed in the central area of ​​the oil cylinder 52, and the oil delivery pipe 8 is connected to one end of the oil guide pipe 54.

[0035] The other end of the oil guide pipe 54 is connected to the central area of ​​the oil cylinder 52 , and the two pistons 53 are respectively connected to the oil guide pipe 54 and the balance support 55 in a penetrating sliding manner. Example

[0036] When using, Figure 1 , Figure 3 , Figure 4 and Figure 5 As shown, the gravel inside the formation carried by the crude oil output during oil production enters the sand filter screen together, and then the crude oil is output through the filtration of the sand filter screen, while the gravel will be blocked and remain inside the sand filter screen and returned to the formation during the interval of production. In this embodiment, the gaps formed by the outer sand filter pipe columns 3 distributed at equal angles on the outside and the inner sand filter pipe columns 4 distributed at equal angles on the inside are arranged in sequence as the sand filter channel. When the crude oil carrying the gravel in the formation is output from the inside of the sand filter screen to the outside, the gravel will be stably blocked in the gap between the outer sand filter pipe column 3 and the inner sand filter pipe column 4, and the crude oil will smoothly pass through the gap between the outer sand filter pipe column 3 and the inner sand filter pipe column 4 to meet the production needs.

[0037] Figure 5 The gap shown in is the sand filter gap set in this embodiment, but in fact the size of the sand filter gap between the outer sand filter screen column 3 and the inner sand filter screen column 4 can be controlled by the well, and the specific adjustment method is as follows:

[0038] First, if Figure 6As shown, the oil injection and pressurizing equipment on the well can be used to inject oil and pressurize the inside of the oil pipeline 8. The hydraulic oil entering the inside of the oil pipeline 8 will be input into the middle space of the oil cylinder 52 through the two upper oil guide pipes 54. As the pressure of the hydraulic oil inside the oil cylinder 52 increases, it will gradually increase and push the pistons 53 symmetrically arranged on both sides outward, so that the two pistons 53 will expand synchronously and symmetrically in opposite directions. The outer ends of the sealing plates of the two pistons 53 will block the sealed oil chamber 51 into three sealed areas. When the two pistons 53 expand outward, the hydraulic oil inside the sealing areas on both sides will have a comprehensive outward pushing effect on the second sealing rubber rings 7 on both sides, so that the two second sealing rubber rings 7 at the upper and lower ends will bulge outward synchronously and push the inner sand filter pipe column 4 outward synchronously through the push rod 41 fixedly connected thereto. At the same time, as the pistons 53 on both sides gradually generate negative pressure away from the central area of ​​the sealed oil chamber 51, a suction force will be generated on the first sealing rubber ring 6 located at the center to approach the center, so that the first The sealing rubber ring 6 gradually concave and synchronously pulls the pull rods 31 distributed around it. At the same time, the pull rods 31 will synchronously pull the outer sand filter pipe column 3 inwardly. At this time, the outer sand filter pipe column 3 distributed at equal angles on the outside gradually retracts inwardly, while the inner sand filter pipe column 4 distributed at equal angles on the inside gradually expands outwardly. The effect achieved is that the sand filter gap between the outer sand filter pipe column 3 and the inner sand filter pipe column 4 gradually narrows so that finer sand and gravel can be screened out. This allows the staff to judge whether it is necessary to narrow the sand filter gap to screen out finer sand and gravel based on the oil quality on the well, thereby achieving the effect of being able to adjust the sand filter gap anytime and anywhere without interrupting production. Similarly, the sand filter gap can be expanded by pumping oil outward through the well equipment. When the oil quality is good, the sand filter gap can be appropriately increased to reduce the flow resistance to increase the oil output rate. At the same time, when the oil quality is poor and contains some fine sand and gravel, the sand filter gap needs to be appropriately narrowed to improve the sand filter quality and effect.

[0039] In addition, a further effect is that when the oil output rate is greatly reduced during oil production, that is, when the filter sand gap is blocked by dense gravel, oil is still injected into the oil pipeline 8 through the oil injection equipment on the well. Similarly, the outer sand filter pipe column 3 retracts inwards, while the inner sand filter pipe column 4 expands outwards. When the outer sand filter pipe column 3 retracts inwards and the inner sand filter pipe column 4 expands outwards to a certain extent, the flexible outer sheath of the outer sand filter pipe column 3 and the flexible outer sheath of the inner sand filter pipe column 4 gradually contact, causing the sand filter pipe to temporarily lose its sand filtering ability. With the continuous injection of hydraulic oil, the outer sand filter pipe column 3 continues to retract inwards and the inner sand filter pipe column 4 expands outwards. 4 continues to expand outward, and the outer and inner positions of the outer sand filter pipe column 3 and the inner sand filter pipe column 4 are alternately satisfied by the elastic deformation after being squeezed between the outer flexible outer covering layers of the outer sand filter pipe column 3 and the inner sand filter pipe column 4, that is, the outer sand filter pipe column 3 will change from the outside to the inside, and the inner sand filter pipe column 4 will change from the inside to the outside. During this period, a large amount of sand and gravel originally blocked in the sand filter gap between the outer sand filter pipe column 3 and the inner sand filter pipe column 4 will be returned to the outside of the sand filter pipe and returned to the formation, so as to achieve the effect of rapid unblocking, without the need to take out the entire mining system and dismantle the sand filter pipe for cleaning and unblocking as in the traditional way, saving time and effort.

[0040] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. Sand filter screen for underground oil production, characterized by: The invention comprises a ring base (1) and an upper ring cover (2), and an outer sand filter pipe column (3) and an inner sand filter pipe column (4) which are arranged at equal angles between the ring base (1) and the upper ring cover (2) and filter sand through adjacent gaps. A central pipe (5) for adjusting the centrifugal distance of the outer sand filter pipe column (3) and the inner sand filter pipe column (4) is arranged at the center of the ring base (1) and the upper ring cover (2), and an oil pipeline (8) for controlling the oil volume is connected through the interior of the central pipe (5); The outer walls of the outer sand filter pipe column (3) and the inner sand filter pipe column (4) are respectively fixed with a pull rod (31) and a push rod (41); A sealing oil chamber (51) is provided at the center of the central tube (5), and a first sealing rubber ring (6) is provided at the center of the sealing oil chamber (51), and the inner end of the pull rod (31) is fixed to the outer wall of the first sealing rubber ring (6), and second sealing rubber rings (7) are symmetrically provided at both ends of the sealing oil chamber (51), and the inner end of the push rod (41) is fixed to the outer wall of the second sealing rubber ring (7); An oil cylinder (52) is fixed at the center of the sealed oil chamber (51), and a piston (53) is symmetrically installed inside the oil cylinder (52), and one end of the piston (53) passes through the oil cylinder (52) and is connected to a sealing disk that seals and separates two sides of the oil cylinder (52).

2. The sand filter screen for downhole oil production according to claim 1, characterized in that: The opposite surfaces of the ring base (1) and the upper ring cover (2) are provided with annular grooves for limiting the outer sand filter pipe column (3) and the inner sand filter pipe column (4); the outer sand filter pipe column (3) and the inner sand filter pipe column (4) are alternately distributed at equal angles, and the inner sand filter pipe column (4) is located on the inner side of the outer sand filter pipe column (3).

3. The sand filter screen for downhole oil production according to claim 1, characterized in that: The outer sand filter pipe column (3) and the inner sand filter pipe column (4) are both composed of an internal hard column core and a wear-resistant flexible outer cladding layer, and a gap for filtering is reserved between the outer sand filter pipe column (3) and the inner sand filter pipe column (4).

4. The sand filter screen for downhole oil production according to claim 1, characterized in that: A first fixing plate (32) and a second fixing plate (42) are fixed at equal angles to the outer sand filter pipe column (3) and the inner sand filter pipe column (4) at each angle between the ring base (1) and the upper ring cover (2), and the pull rod (31) and the push rod (41) are slidably passed through the corresponding first fixing plate (32) and the second fixing plate (42).

5. The sand filter screen for downhole oil production according to claim 1, characterized in that: An oil guide pipe (54) and a balance support (55) are symmetrically installed in the central area of ​​the oil cylinder (52), and an oil delivery pipe (8) is connected to one end of the oil guide pipe (54).

6. The sand filter screen for downhole oil production according to claim 5, characterized in that: The other end of the oil guide pipe (54) is connected to the central area of ​​the oil cylinder (52), and the two pistons (53) are respectively connected to the oil guide pipe (54) and the balance support (55) in a through-type sliding manner.

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