Composite sand control oil and gas separator with sand drainage

Abstract

The application discloses a composite sand prevention oil-gas separator with sand discharging structure, belonging to the technical field of oil-gas separation. The composite sand prevention oil-gas separator comprises a shell, a spiral anchor fixed to the lower side of the shell, a spiral channel formed by the spiral anchor and the shell, an oil discharging channel arranged on the upper side of the shell, oil discharging holes arranged on the shell in a circumferential equidistant distribution mode and communicating the spiral channel and the oil discharging channel, an exhaust channel communicating the upper side of the spiral channel, a bottom shell arranged on the lower side of the shell, a fixed plate fixed in the bottom shell, a connecting rod slidingly connected to the fixed plate, a first spring fixed between the connecting rod and the fixed plate, and a sealing plug fixed to the connecting rod and sealingly sliding on the lower side of the bottom shell. The sealing plug is unblocked to the bottom shell by applying pressure to the oil pipe, so that the sand in the bottom shell is discharged, and the normal operation of the oil-gas separator is ensured.

Description

Technical Field

[0001] This invention relates to the field of oil-gas separation technology, and in particular to a composite sand-proof oil-gas separator with a sand discharge structure. Background Technology

[0002] In the field of oil and gas field development, oil and gas separators, also known as spiral gas anchors, are crucial surface treatment equipment. Their core function is to effectively separate natural gas, liquid hydrocarbons (crude oil), and formation water from well production fluids using the density difference between gas and liquid. Since the produced fluids often carry formation sand, especially in heavy oil or loose sandstone reservoirs where sand production is more severe, conventional oil and gas separators generally adopt structures such as built-in sand-blocking cylinders (screens) or sand-blocking meshes at their inlets as the main sand-blocking methods. These structures are based on the principles of filtration and interception and can effectively block most medium and coarse-sized sand particles. However, the particle size distribution of formation sand is very wide. Among them, there are a large number of fine silt and clay particles, whose particle size is much smaller than the precision of the sand control net or sand control cylinder filter. These fine sand particles will penetrate the primary sand control barrier with the high-speed fluid and enter the interior of the separator body. Once they enter the separator cavity, due to the complex internal flow channels, the change in flow velocity and the effect of gravity, these fine sand particles are very likely to gradually settle and accumulate at the bottom of the container, behind the baffle plate or other flow dead zones, resulting in a continuous increase in the amount of sand inside and a continuous encroachment on the fluid flow space, eventually leading to severe blockage of the internal flow channels of the separator and even the drain pipe. Summary of the Invention

[0003] To overcome the shortcomings of existing oil-gas separators that cannot discharge internal sand, this invention provides a composite sand-proof oil-gas separator with a sand discharge structure.

[0004] The technical solution is as follows: A composite sand-proof oil-gas separator with a sand discharge structure includes a shell, a spiral anchor fixed to the lower side inside the shell, the spiral anchor and the shell forming a spiral channel, an oil discharge channel on the upper side of the shell, and oil discharge holes evenly spaced circumferentially and connecting the spiral channel and the oil discharge channel. The sum of the flow areas of all the oil discharge holes is less than the flow area of ​​the oil discharge channel. An exhaust channel connected to the upper side of the spiral channel is provided on the lower side of the shell. A bottom shell is provided on the lower side of the shell, and oil inlet grooves evenly spaced circumferentially are provided on the bottom shell. The sum of the flow areas of all the oil inlet grooves and the exhaust channel is less than the sum of the flow areas of all the oil discharge holes. A sand-proof mesh is provided in the oil inlet grooves. A fixing plate is fixed inside the bottom shell, and a connecting rod is slidably connected to the fixing plate. A first spring is fixed between the connecting rod and the fixing plate. A sealing plug that slides and seals against the lower side of the bottom shell is fixed to the connecting rod.

[0005] Preferably, the middle part of the sealing plug is shaped like a frustum, and the inner diameter of the lower side of the bottom shell gradually decreases from top to bottom.

[0006] Preferably, the bottom shell is slidably connected to the outer shell, the fixing plate is fixedly connected to a slide rod that is slidably connected to the spiral anchor, the slide rod is slidably connected to the outer shell but not sealed to it, the outer shell is provided with a first cavity, the end of the slide rod away from the fixing plate is fixedly connected to a push plate that is slidably and sealed to the first cavity, and a second spring is fixedly connected between the push plate and the outer shell.

[0007] Preferably, the outer shell is provided with a second cavity located above the first cavity, the second cavity is connected to the oil drain channel, the outer shell is provided with a through hole connecting the second cavity and the first cavity, a pressure plate is slidably connected to the first cavity for limiting and sealing, and a third spring is fixedly connected between the pressure plate and the outer shell.

[0008] Preferably, the sliding range of the push plate is greater than the sliding range of the pressure plate.

[0009] Preferably, the pressure plate is provided with a pressure hole, and a one-way valve is provided in both the pressure hole and the through hole.

[0010] Preferably, the flow area of ​​the oil drain holes that are circumferentially spaced at equal intervals is smaller than the flow area of ​​the oil drain channel.

[0011] Preferably, the outer casing is provided with a pressure relief channel communicating with the first cavity, and a plunger is slidably connected in a sealed manner within the pressure relief channel, and a fourth spring is fixedly connected between the plunger and the outer casing.

[0012] Preferably, the bottom shell is fixedly connected to a sealing sleeve for sealing the outer shell.

[0013] Preferably, the sealing sleeve is made of a deformable material and is used to fit the spiral anchor.

[0014] The present invention has the following advantages: By applying pressure to the oil pipe, the sealing plug is released from the bottom shell, thereby discharging the sand inside the bottom shell and ensuring the normal operation of the oil-gas separator. In the actual oil pumping process, the position of the oil inlet groove is changed by moving the bottom shell, thereby adjusting the length of the spiral channel so that the degree of oil-gas separation reaches the theoretical value, thereby increasing the degree of gas discharge from the oil and reducing the occurrence of gas lock. When the bottom shell moves relative to the outer shell, the sealing sleeve deforms and contacts the spiral anchor, thereby ensuring that the outside of the spiral anchor is in a sealed state and ensuring the efficiency of oil-gas separation. Attached Figure Description

[0015] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0016] Figure 2 This is a three-dimensional structural cross-sectional view of the present invention;

[0017] Figure 3 This is a three-dimensional cross-sectional view of the outer shell and sealing sleeve of the present invention;

[0018] Figure 4 For the present invention Figure 3 Enlarged view of the 3D structure at point A;

[0019] Figure 5 For the present invention Figure 3 Enlarged view of the 3D structure at point B;

[0020] Figure 6 For the present invention Figure 3 Enlarged view of the 3D structure at point C.

[0021] The meanings of the reference numerals in the figure are as follows: 1: outer shell, 101: spiral channel, 102: oil drain channel, 103: oil drain hole, 104: exhaust channel, 105: first cavity, 106: second cavity, 107: through hole, 108: pressure relief channel, 2: spiral anchor, 3: bottom shell, 301: oil inlet groove, 4: fixing plate, 5: connecting rod, 6: first spring, 7: sealing plug, 8: slide rod, 9: push plate, 10: second spring, 11: pressure plate, 1101: pressure hole, 12: third spring, 13: plunger, 14: fourth spring, 16: sealing sleeve. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. It is hereby declared that the terms "up," "down," "left," "right," "inner," and "outer," etc., appearing or about to appear in this text, are based solely on the accompanying drawings and are not intended to specifically limit the invention. Example 1

[0023] Although existing oil-gas separators are equipped with sand-proof cylinders or sand-proof nets, small-sized sand particles can still enter the oil-gas separator and accumulate over time, causing the oil-gas separator to become clogged with sand.

[0024] A composite sand-proof oil-gas separator with a sand discharge structure, such as Figures 1-4As shown, the device includes an outer shell 1, with a spiral anchor 2 fixed to the lower side inside the outer shell 1. The spiral anchor 2 and the outer shell 1 cooperate to form a spiral channel 101. An oil drain channel 102 is provided on the upper side of the outer shell 1. The oil drain channel 102 includes an annular channel and an upper cylindrical channel. The outer shell 1 is provided with oil drain holes 103 that are circumferentially evenly distributed and connect the spiral channel 101 and the oil drain channel 102. The sum of the flow areas of all the oil drain holes 103 is less than the flow area of ​​the oil drain channel 102. The oil drain holes 103 are located on the upper side of the spiral channel 101. The outer shell 1 is provided with an exhaust channel 104 that communicates with the upper side of the spiral channel 101. The exhaust channel 104 communicates with the annular space of the oil pipe and the casing. A bottom shell 3 is provided on the lower side of the outer shell 1. This embodiment In the example, the bottom shell 3 and the outer shell 1 are considered to be fixedly connected. The middle of the outer side of the bottom shell 3 is provided with circumferentially evenly distributed oil inlet grooves 301. The sum of the flow area of ​​all oil inlet grooves 301 and the flow area of ​​exhaust channel 104 is less than the sum of the flow area of ​​all oil drain holes 103. The oil inlet grooves 301 are provided with sandproof mesh. The lower side of the bottom shell 3 is fixedly connected with two symmetrically distributed fixing plates 4. The fixing plates 4 are slidably connected with connecting rods 5. A first spring 6 is fixedly connected between the connecting rods 5 and the fixing plates 4. The lower ends of the two connecting rods 5 are jointly fixedly connected with sealing plugs 7 that slide and seal against the lower side of the bottom shell 3. The middle part of the sealing plug 7 is set as a frustum shape. The inner diameter of the lower side of the bottom shell 3 gradually decreases from top to bottom to guide the sand and facilitate the sand to be discharged from the lower side of the bottom shell 3.

[0025] This oil-gas separator is installed at the lower end of the tubing. During oil extraction, the oil in the well enters the bottom shell 3 and the lower side of the outer shell 1 through the inlet groove 301. As the oil passes through the sand-prevention mesh on the inlet groove 301, most of the sand carried in the oil is intercepted by the sand-prevention mesh. The filtered oil comes into contact with the spiral anchor 2 and flows upward along the spiral channel 101. During the flow of the oil along the spiral channel 101, the oil rotates under the guidance of the spiral anchor 2. Since the density of the gas carried in the oil is lower than that of the oil, centrifugal force is generated during the rotation. Therefore, the oil is thrown to the side closer to the inner wall of the outer shell 1, while the gas is located in the middle of the outer shell 1. The oil and gas are finally located above the spiral channel 101. The oil enters the drain channel 102 through the drain hole 103, while the gas is discharged into the annular space of the tubing and casing through the exhaust channel 104. The process achieves oil-gas separation, but the oil entering the spiral channel 101 also carries small sand particles. During the downstroke after the upstroke of the oil extraction process, the sand in the spiral channel 101 accumulates on the lower side of the bottom shell 3. When it is necessary to clean the sand in the bottom shell 3, the operator pressurizes the outer shell 1. Since the sum of the flow areas of all oil inlet grooves 301 and the flow areas of exhaust channels 104 is less than the sum of the flow areas of all oil outlet holes 103, the pressure in the outer shell 1 increases, causing the sealing plug 7 to move the connecting rod 5 downward. The first spring 6 is compressed, and the sealing plug 7 no longer seals the lower side of the bottom shell 3. The sand in the bottom shell 3 is discharged. During the sand discharge process, the frustum shape in the middle of the sealing plug 7, combined with the characteristic that the inner diameter of the lower side of the bottom shell 3 gradually decreases from top to bottom, guides the sand, making it easier for the sand to be discharged quickly and ensuring the normal operation of the oil-gas separator. Example 2

[0026] Based on Example 1, a composite sand-proof oil-gas separator with a sand discharge structure is provided, such as... Figure 2 , Figure 3 and Figure 5As shown, the bottom shell 3 is slidably connected to the outer shell 1. Two fixed plates 4 are jointly fixed to a slide rod 8 that is slidably connected to the spiral anchor 2. The slide rod 8 is slidably connected to the outer shell 1 but not sealed to it (this sliding connection is located on the upper side of the exhaust channel 104). The outer shell 1 is provided with a first cavity 105 located above the exhaust channel 104. The upper end of the slide rod 8 is fixed to a push plate 9 that is slidably and sealed to the first cavity 105. A second spring 10 is fixed between the push plate 9 and the outer shell 1. The outer shell 1 is provided with a second cavity 106 located above the first cavity 105. The second cavity 106 communicates with the cylindrical channel of the oil drain channel 102. The outer shell 1 is provided with a spring that connects the second cavity to the oil drain channel 102. 106 is connected to the through hole 107 of the first cavity 105. The first cavity 105 is connected to the pressure plate 11 by a limiting seal sliding connection. The pressure plate 11 is fixed to the outer shell 1 by a third spring 12. The sliding range of the push plate 9 is greater than the sliding range of the pressure plate 11. By limiting the movement range of the pressure plate 11, the accuracy of the adjustment process is ensured. The pressure plate 11 is provided with a pressure hole 1101. Both the pressure hole 1101 and the through hole 107 are provided with a one-way valve. Both the pressure hole 1101 and the one-way valve in the through hole 107 are used to supply oil to flow downward. The flow area of ​​the oil drain holes 103 distributed circumferentially at equal intervals is smaller than the flow area of ​​the oil drain channel 102.

[0027] During the flow of oil through the spiral channel 101, the length of the spiral channel 101 through which the oil flows determines the degree of oil and gas separation. Generally, before installation, operators pre-set the length of the spiral channel 101 based on the downhole oil and gas conditions; this theoretical length cannot be changed during subsequent oil extraction. However, during oil extraction, the downhole environment can influence the actual separation of oil and gas, resulting in low gas separation and inefficient venting. This oil-gas separator ensures oil-gas separation by adjusting the working length of the spiral channel 101 during actual oil extraction. The specific operation is as follows: Initial... In the initial state, taking a low degree of oil-gas separation as an example, the working length of the spiral channel 101 needs to be extended. The operator pressurizes the oil pipe using a pump truck installed on the ground. Because the flow area of ​​the circumferentially evenly distributed oil drain holes 103 is smaller than the flow area of ​​the oil drain channel 102, the oil in the oil drain channel 102 cannot quickly flow back into the spiral channel 101 through the oil drain holes 103. This causes the pressure in the oil drain channel 102 to be greater than the pressure in the spiral channel 101. The increased pressure on the pressure plate 11 pushes it downward, and the one-way valve in the pressure hole 1101 closes. The downward movement of the pressure plate 11 increases the pressure in the second cavity 106, and the through hole 107... The internal check valve opens, and the pressure plate 11 pushes the oil below it through the check valve in the through hole 107 to the top of the push plate 9 in the first cavity 105. The push plate 9 moves downward under pressure, the second spring 10 is compressed, and the push plate 9 drives the slide rod 8, the fixing plate 4 and the bottom shell 3 to move downward. The oil inlet groove 301 moves downward, which extends the working distance of the spiral channel 101, thereby changing the degree of subsequent oil-gas separation. Subsequently, the operator stops pressurizing the oil pipe, the pressure plate 11 moves upward, and the area above the push plate 9 in the second cavity 106 is under high pressure. The check valve in the through hole 107 closes, and at the same time, the pressure below the pressure plate 11 in the second cavity 106 decreases, and the pressure hole 110... When the internal one-way valve 1 opens, the oil in the drain channel 102 enters the pressure plate 11 below the second cavity 106 through the pressure hole 1101. Then, the operator observes the increase in the amount of separated gas through the wellhead gas collection device. The operator continues to repeat the above steps to continuously pressurize the tubing, so that the amount of gas separated reaches the maximum. By limiting the movement range of the pressure plate 11, the accuracy of the adjustment process is ensured. Since the downhole pressure is unstable, when pressurizing the tubing, excessive pressure is applied to make the pressure plate 11 move downward a constant distance each time, thereby controlling the distance that the bottom shell 3 moves downward at one time, so as to precisely regulate the flow path of the oil. Example 3

[0028] Based on Example 2, a composite sand-proof oil-gas separator with a sand discharge structure is provided, such as... Figure 3 and Figure 5As shown, the outer casing 1 is provided with a pressure relief channel 108 communicating with the first cavity 105. The pressure relief channel 108 is located to the right of the through hole 107. A plunger 13 is slidably connected inside the pressure relief channel 108. A fourth spring 14 is fixedly connected between the plunger 13 and the outer casing 1. Figure 5 As shown, when the pressure in the oil discharge channel 102 is greater than the pressure in the spiral channel 101, the plunger 13 is blocked below, preventing it from moving downwards.

[0029] In Example 2, the pressure inside the drain channel 102 is greater than the pressure inside the spiral channel 101, causing the pressure plate 11 to move downwards. Simultaneously, the plunger 13 is blocked below, preventing it from moving downwards. Therefore, the plunger 13 cannot move downwards, connecting the pressure relief channel 108 with the first cavity 105. At the same time, the oil pipe is under negative pressure during oil extraction. This negative pressure prevents the plunger 13 from moving upwards to compress the fourth spring 14. When the position of the bottom shell 3 needs to be adjusted upwards, the operator needs to further increase the negative pressure intensity under the working negative pressure condition of the oil pipe for extraction. At this time, because the oil in the spiral channel 101 cannot quickly pass through the drain hole 103... As the oil enters the drain channel 102, the pressure inside the drain channel 102 is greater than the pressure inside the spiral channel 101. The pressure inside the drain channel 102 causes the plunger 13 to move upward, and the fourth spring 14 is compressed. When the plunger 13 no longer blocks the lower side of the pressure relief channel 108, the elastic force of the second spring 10 is released, causing the push plate 9 to move upward. The push plate 9 causes the slide rod 8, the fixed plate 4, and the bottom shell 3 to move upward. The push plate 9 pushes the oil above it into the drain channel 102 through the pressure relief channel 108. The operator controls the distance the bottom shell 3 moves upward by controlling the opening time of the lower side of the pressure relief channel 108, thereby ensuring the control of the position of the bottom shell 3. Example 4

[0030] Based on Example 3, a composite sand-proof oil-gas separator with a sand discharge structure is provided, such as... Figure 2 , Figure 3 and Figure 6 As shown, the bottom shell 3 is fixedly connected to a sealing sleeve 16 for sealing the outer shell 1. The sealing sleeve 16 is made of a deformable material. Initially, the sealing sleeve 16 is fitted onto the outside of the outer shell 1, and at this time, the sealing sleeve 16 is in an expanded and deformed state. During the downward movement of the bottom shell 3, the bottom shell 3 drives the sealing sleeve 16 to move downward. When the lower side of the sealing sleeve 16 is no longer in contact with the outer shell 1, the sealing sleeve 16 deforms and contacts the spiral anchor 2, thereby ensuring that the outer side of the spiral anchor 2 is in a sealed state, ensuring the accuracy of the working length after the spiral channel 101 is adjusted, and ensuring the efficiency of oil-gas separation.

[0031] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A composite sand-proof oil-gas separator with a sand discharge structure, comprising a shell (1), a spiral anchor (2) fixedly connected to the lower side inside the shell (1), the spiral anchor (2) and the shell (1) forming a spiral channel (101), an oil discharge channel (102) provided on the upper side of the shell (1), the shell (1) being provided with oil discharge holes (103) evenly distributed in the circumferential direction and connecting the spiral channel (101) and the oil discharge channel (102), the sum of the flow areas of all the oil discharge holes (103) being less than the flow area of ​​the oil discharge channel (102), and the shell (1) being provided with an exhaust channel (104) communicating with the upper side of the spiral channel (101), characterized in that, The lower side of the outer shell (1) is provided with a bottom shell (3), the bottom shell (3) is provided with oil inlet grooves (301) distributed circumferentially at equal intervals, the sum of the flow area of ​​all the oil inlet grooves (301) and the flow area of ​​the exhaust channel (104) is less than the sum of the flow areas of all the oil drain holes (103), the oil inlet grooves (301) are provided with sandproof mesh, a fixing plate (4) is fixedly connected inside the bottom shell (3), the fixing plate (4) is slidably connected with a connecting rod (5), a first spring (6) is fixedly connected between the connecting rod (5) and the fixing plate (4), and a sealing plug (7) is fixedly connected to the connecting rod (5) and slides with the lower side of the bottom shell (3); When it is necessary to clean the sand inside the bottom shell (3), the operator pressurizes the outer shell (1). Since the sum of the flow area of ​​all the oil inlet grooves (301) and the flow area of ​​the exhaust channel (104) is less than the sum of the flow areas of all the oil drain holes (103), the pressure inside the outer shell (1) increases, causing the sealing plug (7) to drive the connecting rod (5) to move downward. The first spring (6) is compressed, and the sealing plug (7) no longer seals the lower side of the bottom shell (3), and the sand inside the bottom shell (3) is discharged.

2. The composite sand-proof oil-gas separator with a sand discharge structure according to claim 1, characterized in that, The middle part of the sealing plug (7) is shaped like a frustum, and the inner diameter of the bottom shell (3) gradually decreases from top to bottom.

3. A composite sand-proof oil-gas separator with a sand discharge structure according to claim 1, characterized in that, The bottom shell (3) is slidably connected to the outer shell (1). The fixing plate (4) is fixedly connected to the slide rod (8) which is slidably connected to the spiral anchor (2). The slide rod (8) is slidably connected to the outer shell (1) but not sealed to it. The outer shell (1) is provided with a first cavity (105). The end of the slide rod (8) away from the fixing plate (4) is fixedly connected to a push plate (9) which is slidably and sealed to the first cavity (105). A second spring (10) is fixedly connected between the push plate (9) and the outer shell (1).

4. A composite sand-proof oil-gas separator with a sand discharge structure according to claim 3, characterized in that, The outer shell (1) is provided with a second cavity (106) located above the first cavity (105). The second cavity (106) is connected to the oil drain channel (102). The outer shell (1) is provided with a through hole (107) connecting the second cavity (106) and the first cavity (105). A pressure plate (11) is slidably connected to the first cavity (105) with a limiting seal. A third spring (12) is fixed between the pressure plate (11) and the outer shell (1).

5. A composite sand-proof oil-gas separator with a sand discharge structure according to claim 4, characterized in that, The sliding range of the push plate (9) is greater than the sliding range of the pressure plate (11).

6. A composite sand-proof oil-gas separator with a sand-discharging structure according to claim 5, characterized in that, The pressure plate (11) is provided with a pressure hole (1101), and a one-way valve is provided in both the pressure hole (1101) and the through hole (107).

7. A composite sand-proof oil-gas separator with a sand-discharging structure according to claim 6, characterized in that, The flow area of ​​the oil drain holes (103) that are circumferentially spaced at equal intervals is smaller than the flow area of ​​the oil drain channel (102).

8. A composite sand-proof oil-gas separator with a sand-discharging structure according to claim 7, characterized in that, The outer shell (1) is provided with a pressure relief channel (108) communicating with the first cavity (105). A plunger (13) is slidably connected in the pressure relief channel (108). A fourth spring (14) is fixed between the plunger (13) and the outer shell (1).

9. A composite sand-proof oil-gas separator with a sand discharge structure according to claim 8, characterized in that, The bottom shell (3) is fixedly connected to a sealing sleeve (16) for sealing the outer shell (1).

10. A composite sand-proof oil-gas separator with a sand discharge structure according to claim 9, characterized in that, The sealing sleeve (16) is made of a deformable material and is used to fit the spiral anchor (2).

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