Downhole oil-water multi-stage cyclone purification device for co-well injection and production

Abstract

The present invention relates to an underground oil-water multi-stage cyclone purification device for co-well injection and production. It includes a general outer shell, an end cap, a first-stage cyclone module, a second-stage cyclone module, and a third-stage cyclone module. The first-stage cyclone module, the second-stage cyclone module, and the third-stage cyclone module are connected in sequence from top to bottom and arranged inside the general outer shell to form a three-stage variable-size composite inverted-cone type oil-water separation device. The end cap is arranged at the upper port of the general outer shell, and the end cap has an oil-phase outlet. The upper end of the general outer shell is evenly distributed with external feed ports; an external bridge channel is threadedly connected to the general outer shell and is located between the general outer shell and the outer part of the first-stage outer shell; the first-stage cyclone module is connected to the second-stage cyclone module through a first-stage internal bridge channel, the second-stage cyclone module is connected to the third-stage cyclone module through a second-stage internal bridge channel, and the third-stage spiral flow channel of the third-stage cyclone module has an annular sealing partition plate, and the annular sealing partition plate divides the oil-casing annulus into two parts. The present invention combines an inverted cone and a three-stage separation system, enhances the oil-water separation efficiency through the internal flow channels, and realizes efficient oil-water two-phase separation.

Description

Technical Field

[0001] The present invention relates to the field of petrochemical engineering and downhole oil-water separation devices, and particularly to a downhole oil-water multi-stage cyclone purification device for co-well injection and production. Background Art

[0002] With the increasing demand for oil, most onshore oil fields in China have entered the middle and late stages of development. The water cut of the produced fluid is continuously increasing, and the treatment capacity of surface water treatment equipment cannot meet the actual needs. Moreover, it is difficult to transform the existing separation system due to space limitations; the development of marginal small fault-block oil fields is gradually underway, but due to low productivity, few wells, large well spacing, fast water breakthrough in oil wells, and short oil production period, improving the economic benefits of marginal small fault-block oil field exploitation is the main problem to be solved; therefore, it is very necessary to design an efficient hydrocyclone. In the existing downhole multi-stage cyclone coalescence oil-water separation device, although the efficiency of oil-water separation can be improved through two-stage separation, there are still many deficiencies. Firstly, although it is a two-stage separation, only one-stage cyclone is provided with an inverted cone, and the separation effect is not perfect. Secondly, it cannot solve the oil attached to the inverted cone and some unseparated oil near the inverted cone. Finally, it cannot change the total length of the inverted cone, and if it encounters a working condition that requires a long or short inverted cone, it cannot achieve the expected separation effect. The present invention innovatively uses modular design to solve this problem, which requires a downhole oil-water multi-stage cyclone purification device for co-well injection and production to achieve efficient separation of downhole oil-water media. Summary of the Invention

[0003] The object of the present invention is a downhole oil-water multi-stage cyclone purification device for co-well injection and production, which is used to solve the problems that the separation effect of the existing downhole oil-water separation device is not perfect and it cannot solve the oil attached to the inverted cone and some unseparated oil near the inverted cone.

[0004] The technical solution adopted by the present invention to solve its technical problems is as follows: This downhole oil-water multi-stage cyclone purification device for co-well injection and production includes a general outer shell, an end cover, a first-stage cyclone module, a second-stage cyclone module, and a third-stage cyclone module. The first-stage cyclone module, the second-stage cyclone module, and the third-stage cyclone module are connected in sequence from top to bottom and arranged inside the general outer shell to form a three-stage variable-size composite inverted cone type oil-water separation device. The end cover is arranged at the upper port of the general outer shell. The end cover has an oil-phase outlet, and the upper end of the general outer shell is evenly provided with external feed ports; The first-stage cyclone module includes an external bridge channel, a first-stage outer shell, a first-stage spiral channel, a first-stage inverted cone, and a first-stage internal bridge channel. The first-stage spiral channel and the first-stage inverted cone are arranged at intervals inside the first-stage outer shell. A gap channel is arranged between the first-stage spiral channel and the end cover. The first-stage spiral channel is provided with a central hole. The lower end of the first-stage outer shell is connected to the first-stage internal bridge channel. The upper end of the first-stage internal bridge channel is welded to the bottom section of the first-stage inverted cone. The first-stage internal bridge channel has a first-stage oil-phase confluence inlet communicating with the oil-casing annulus; The external bridge channel is cylindrical. Radial feed channels are evenly arranged on the circumferential direction of the cylindrical wall of the external bridge channel. Oil-phase channels are evenly arranged on the axial direction of the cylindrical wall of the external bridge channel. The external bridge channel is threadedly connected to the general outer shell and is located between the general outer shell and the outside of the first-stage outer shell. The external bridge channel is tightly fitted with the first-stage outer shell. The first-stage outer shell is evenly provided with internal feed ports. Each external feed port, feed channel, and internal feed port correspond one by one;

[0005] The first-stage cyclone module is connected to the second-stage cyclone module through the first-stage internal bridge channel. The second-stage cyclone module is connected to the third-stage cyclone module through the second-stage internal bridge channel. The third-stage spiral channel of the third-stage cyclone module has an annular sealing partition board. The annular sealing partition board has an external thread and is threadedly connected to the general outer shell. The annular sealing partition board divides the oil-casing annulus formed between the first-stage cyclone module, the second-stage cyclone module, the third-stage cyclone module and the general outer shell into two parts.

[0006] In the above solution, the second-stage cyclone module includes a second-stage outer shell, a second-stage spiral channel, a second-stage inverted cone, and a second-stage internal bridge channel. The second-stage spiral channel and the second-stage inverted cone are arranged at intervals inside the second-stage outer shell. The second-stage spiral channel is provided with a central hole. The second-stage internal bridge channel has a second-stage oil-phase confluence inlet communicating with the oil-casing annulus. The second-stage internal bridge channel also has a second-stage mixed-phase channel and a second-stage oil-phase channel; The second-stage spiral channel is connected to the first-stage internal bridge channel by welding. The second-stage outer shell is connected to the second-stage spiral channel by threaded connection; The second-stage internal bridge channel is threadedly connected to the second-stage outer shell. The upper end of the second-stage internal bridge channel is welded to the bottom section of the second-stage inverted cone. The lower end of the second-stage internal bridge channel is connected to the third-stage spiral channel by welding.

[0007] In the above solution, the three-stage swirl module includes a three-stage outer shell, a three-stage spiral flow channel, and a three-stage inverted cone. The three-stage spiral flow channel and the three-stage inverted cone are arranged at intervals within the three-stage outer shell. The three-stage spiral flow channel is provided with a central hole. The three-stage spiral flow channel is connected to the three-stage outer shell by threads, and the three-stage spiral flow channel is connected to the second-stage inner bridge channel by welding. The bottom section of the three-stage inverted cone is connected to the three-stage outer shell by welding.

[0008] In the above solution, the first-stage inverted cone, the second-stage inverted cone, and the third-stage inverted cone are all formed by connecting multiple inverted cone segments to each other through snap rings. Each inverted cone segment is integrally composed of a guiding platform, a cone body, and a guiding groove. The guiding platform is in the shape of a frustum of a cone, and corrugated ribs are evenly distributed around the frustum of the cone. A snap ring is provided at the top of the guiding platform. The guiding groove is a frustum-shaped groove at the bottom of the cone body, and corrugated grooves are evenly distributed around the inner wall of the frustum-shaped groove. The guiding groove has a snap ring groove. An axial inner cone main flow channel is provided in the guiding platform and the cone body. Adjacent two inverted cone segments are connected by inserting the guiding platform into the guiding groove and the snap ring being stuck in the snap ring groove. After each corrugated rib is inserted into the corresponding corrugated groove, the corrugated rib and the corrugated groove form a guiding flow channel, and each guiding flow channel is connected to the inner cone main flow channel through an inner cone branch flow channel.

[0009] In the above solution, the first-stage inner bridge channel includes an outer cylinder and an inner column arranged coaxially. The first-stage outer shell is threadedly connected to the annular space between the outer cylinder and the inner column. The top plate of the second-stage spiral flow channel is fixed to the outer cylinder and closes the bottom of the annular space. The first-stage oil phase channel in the inner column communicates with the annular space, and the annular space communicates with the first-stage oil phase inlet. The inner column also has a first-stage mixed phase channel. The first-stage oil phase channel communicates with the central hole of the second-stage spiral flow channel through the central hole of the top plate of the second-stage spiral flow channel, and the first-stage mixed phase channel communicates with the second-stage outer shell through the central hole of the top plate of the second-stage spiral flow channel.

[0010] In the above solution, the first-stage spiral flow channel is connected to the first-stage outer shell by threads. The first-stage inverted cone is formed by connecting the first-stage inverted cone top section, the first-stage inverted cone upper cone section, the first-stage inverted cone middle cone section, the first-stage inverted cone lower cone section, the first-stage inverted cone column section top, the first-stage inverted cone upper column section, the first-stage inverted cone middle column section, the first-stage inverted cone lower column section, the first-stage inverted cone column section bottom, and the first-stage inverted cone bottom section to each other through corresponding snap rings and snap ring grooves. The first-stage inner bridge channel is connected to the second-stage spiral flow channel by welding.

[0011] In the above solution, the second-stage inverted cone is formed by connecting the second-stage inverted cone top section, the second-stage inverted cone upper cone section, the second-stage inverted cone middle cone section, the second-stage inverted cone lower cone section, the second-stage inverted cone column section top, the second-stage inverted cone upper column section, the second-stage inverted cone middle column section, the second-stage inverted cone lower column section, the second-stage inverted cone column section bottom, and the second-stage inverted cone bottom section to each other through snap rings.

[0012] In the above scheme, the three-level inverted cone is composed of a three-level inverted cone top section, a three-level inverted cone upper cone section, a three-level inverted cone middle cone section, a three-level inverted cone lower cone section, a three-level inverted cone column section top, a three-level inverted cone upper column section, a three-level inverted cone middle column section, a three-level inverted cone lower column section, a three-level inverted cone column section bottom, and a three-level inverted cone bottom section which are interconnected by a clamping ring.

[0013] In the above scheme, the oil casing annulus corresponding to the primary cyclone module and the secondary cyclone module, the oil phase channel of the external bridge channel, the gap flow channel between the primary spiral flow channel and the end cover, and the oil phase outlet constitute the oil upward channel. Beneficial Effects

[0014] 1. The present invention is a three-stage flow diversion device with variable size. After the oil and water phases are initially separated by the first-stage cyclone, separated again by the second-stage cyclone, and finally separated by the third-stage cyclone, they are collected into the oil phase outlet through the oil liquid upward channel, and the water is discharged from the water phase outlet, which greatly improves the separation efficiency.

[0015] 2. The present invention can transport the oil phase after multiple separations to the oil phase outlet through the bridge channel.

[0016] 3. In the inverted cone of the present invention, after the oil-water two phases are separated by cyclone, some unseparated oil phase adheres to the inverted cone and is sucked into the internal flow channel by the flow channel opening between the cone section and the column section, and then discharged through the oil phase outlet, thereby achieving the effect of improving the separation efficiency.

[0017] 4. The present invention designs the inverted cone structure into a modular structure, and the total length of the inverted cone can be controlled by increasing or decreasing the number of column sections to adapt to different working conditions and achieve the best separation efficiency.

[0018] 5. The present invention has the advantages of high separation efficiency and strong applicability. It can achieve efficient separation of oil-water two-phase media under various working conditions, greatly improving economic benefits. At the same time, the modular design makes the device itself universal, which is easy to optimize to adapt to specific working conditions to achieve the best separation efficiency. It is a multi-phase medium efficient separation device suitable for underground wells.

[0019] 6. In order to solve the technical problems mentioned in the background technology, the present invention provides a multi-stage cyclone purification device for oil and water injection and production in the same well, which can separate the oil-water mixed phase multiple times through a new three-stage variable-size cyclone. The new inverted cone inside can suck the oil phase attached to the inverted cone into the central flow channel (main flow channel inside the cone) and make it enter the internal vortex, thereby realizing efficient separation of the oil and water phases.

[0020] 7. The present invention has a simple structure, high separation efficiency, and modular design, and can achieve efficient separation of multiple media under various working conditions. It is an oil-water two-phase efficient separation device suitable for the field of downhole oil-water separation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 These are the overall appearance and cross-sectional view of the present invention.

[0022] Figure 2 These are the appearance views of the primary cyclone module, secondary cyclone module, and tertiary cyclone module.

[0023] Figure 3 These are the cross-sectional view and partial enlarged view of the primary cyclone module.

[0024] Figure 4 These are the partial exploded views of the primary cyclone module.

[0025] Figure 5 These are the overall appearance, partial cross-sectional view, and exploded view of the inverted cone of the primary cyclone module.

[0026] Figure 6 These are the overall appearance and cross-sectional view of the secondary cyclone module.

[0027] Figure 7 These are the exploded views of the secondary cyclone module.

[0028] Figure 8 These are the overall appearance and cross-sectional view of the tertiary cyclone module.

[0029] Figure 9 These are the exploded views of the tertiary cyclone module.

[0030] In the figure, 1 is the primary cyclone module, 101 is the overall housing, 1011 is the external feed inlet, 102 is the end cap, 1021 is the oil phase outlet, 103 is the external bridge channel, 1031 is the feed channel, 1032 is the oil phase channel, 104 is the primary spiral flow channel, 105 is the primary housing, 1051 is the internal feed inlet, 106 is the primary inverted cone top section, 107 is the primary inverted cone upper cone section, 108 is the primary inverted cone middle cone section, 1081 is the snap ring, 1082 is the flow guiding platform, 1083 is the main flow channel inside the cone, 1084 is the snap ring groove, 1085 is the branch flow channel inside the cone, 1086 is the flow guiding groove, 109 is the primary inverted cone lower cone section, 110 is the top of the primary inverted cone column section, 111 is the upper column section of the primary inverted cone, 112 is the middle column section of the primary inverted cone, 113 is the lower column section of the primary inverted cone, 114 is the bottom of the primary inverted cone column section, 115 is the bottom section of the primary inverted cone, 116 is the primary internal bridge channel, 1161 is the primary oil phase channel, 1162 is the primary oil phase confluence inlet, 1163 is the primary mixed phase channel, 2 is the secondary cyclone module, 201 is the secondary spiral flow channel, 202 is the secondary housing, 203 is the secondary inverted cone top section, 204 is the secondary inverted cone upper cone section, 205 is the secondary inverted cone middle cone section, 206 is the secondary inverted cone lower cone section, 207 is the top of the secondary inverted cone column section, 208 is the upper column section of the secondary inverted cone, 209 is the middle column section of the secondary inverted cone, 210 is the lower column section of the secondary inverted cone, 211 is the bottom of the secondary inverted cone column section, 212 is the bottom section of the secondary inverted cone, 213 is the secondary internal bridge channel, 2131 is the secondary oil phase channel, 2132 is the secondary oil phase confluence inlet, 2133 is the secondary mixed phase channel, 3 is the tertiary cyclone module, 301 is the tertiary spiral flow channel, 302 is the tertiary housing, 303 is the tertiary inverted cone top section, 304 is the tertiary inverted cone upper cone section, 305 is the tertiary inverted cone middle cone section, 306 is the tertiary inverted cone lower cone section, 307 is the top of the tertiary inverted cone column section, 308 is the upper column section of the tertiary inverted cone, 309 is the middle column section of the tertiary inverted cone, 310 is the lower column section of the tertiary inverted cone, 311 is the bottom of the tertiary inverted cone column section, 312 is the bottom section of the tertiary inverted cone. Detailed implementation mode

[0031] The following further describes the present invention in conjunction with the accompanying drawings:

[0032] The overall appearance and cross-sectional view of this downhole oil-water multi-stage cyclone purification device for simultaneous injection and production in the same well are as Figure 1As shown in the figure, this downhole oil-water multi-stage cyclone purification device for co-production injection and production includes a general housing 101, an end cover 102, a first-stage cyclone module 1, a second-stage cyclone module 2, and a third-stage cyclone module 3. The first-stage cyclone module 1, the second-stage cyclone module 2, and the third-stage cyclone module 3 are connected in sequence from top to bottom and are arranged in the general housing 101 to form a three-stage variable-size composite inverted-cone type oil-water separation device. The end cover 102 is arranged at the upper port of the general housing 101. The end cover 102 has an oil-phase outlet 1021. The upper end of the general housing is evenly distributed with external feed ports 1011. A gap flow channel is arranged between the first-stage spiral channel 104 and the end cover 102. The first-stage spiral channel 104 is provided with a central hole. The lower end of the first-stage housing 105 is connected to a first-stage internal bridge channel 116. The upper end of the first-stage internal bridge channel is welded to the bottom section of the first-stage inverted cone 115. The first-stage internal bridge channel has a first-stage oil-phase confluence inlet 1162 that communicates with the oil-casing annulus. The external bridge channel 103 is cylindrical. Radial feed channels 1031 are evenly arranged on the circumferential direction of the cylindrical wall of the external bridge channel. Oil-phase channels 1032 are evenly arranged on the axial direction of the cylindrical wall of the external bridge channel. The external bridge channel is threadedly connected to the general housing and is located between the general housing and the outside of the first-stage housing. The external bridge channel is in a tight fit with the first-stage housing. The first-stage housing is evenly provided with internal feed ports 1051. Each external feed port, feed channel, and internal feed port correspond to each other.

[0033] The first-stage cyclone module 1 is connected to the second-stage cyclone module 2 through the first-stage internal bridge channel 116. The second-stage cyclone module 2 is connected to the third-stage cyclone module 3 through the second-stage internal bridge channel 213. The third-stage spiral channel 301 of the third-stage cyclone module 3 has an annular sealing partition board. The annular sealing partition board has an external thread and is threadedly connected to the general housing. The annular sealing partition board divides the oil-casing annulus formed between the first-stage cyclone module 1, the second-stage cyclone module 2, and the third-stage cyclone module 3 and the general housing 101 into two parts. The oil-casing annulus corresponding to the first-stage cyclone module 1 and the second-stage cyclone module 2, the oil-phase channels of the external bridge channel 103, the gap flow channel between the first-stage spiral channel 104 and the end cover 102, and the oil-phase outlet 1021 constitute an oil liquid upward channel.

[0034] The first-stage internal bridge channel 116 includes an outer cylinder and an inner column arranged coaxially. The first-stage housing 105 is threadedly connected to the annular space between the outer cylinder and the inner column. The top plate of the second-stage spiral channel 201 is fixed to the outer cylinder and closes the bottom of the annular space. The first-stage oil-phase channel 1161 in the inner column body communicates with the annular space. The annular space communicates with the first-stage oil-phase confluence inlet 1162. The inner column body also has a first-stage mixed-phase channel 1163. The first-stage oil-phase channel 1161 communicates with the central hole of the second-stage spiral channel through the central hole of the top plate of the second-stage spiral channel. The first-stage mixed-phase channel 1163 communicates with the second-stage housing through the central hole of the top plate of the second-stage spiral channel.

[0035] The device is vertically placed downhole. During operation, the oil-water mixture first flows in from the outer feed port 1011, then passes through the feed channel 1031 of the outer bridge channel 103, and finally enters the first-stage hydrocyclone through the inner feed port 1051. After passing through the first-stage spiral channel 104, it obtains sufficient tangential velocity and undergoes preliminary separation inside the first-stage outer shell 105. Part of the oil phase is separated and discharged through the oil-phase outlet 1021; some of the oil phase that is not separated in the center adheres to the inverted cone and is sucked into the inner-branch channel 1085 in the cone by the diversion groove 1086 between the conical section and the column section, then enters the inner-main channel 1083 and is discharged from the top, and finally enters the inner swirl and is discharged through the oil-phase outlet 1021. This is the first-stage separation process. The remaining part of the unseparated mixed phase that enters the bottom outlet enters the second-stage hydrocyclone module 2 through the first-stage mixed-phase channel 1163 in the first-stage inner bridge channel 116, and then enters the second-stage spiral channel 201 to obtain sufficient tangential velocity and undergoes re-separation inside the second-stage outer shell 202. The central hole of the second-stage spiral channel 201 is connected to the first-stage oil-phase channel 1161 in the first-stage inner bridge channel 116. Part of the oil phase is separated and passes through the first-stage oil-phase channel 1161 in the first-stage inner bridge channel 116, and then enters the oil-casing annulus through the first-stage oil-phase convergence inlet, so as to converge with the previously separated oil phase through the oil-phase channel 1032 in the outer bridge channel 103 and be discharged from the oil-phase outlet 1021. Some of the oil phase that is not separated in the center adheres to the inverted cone and is sucked into the inner-branch channel in the cone by the diversion groove, then enters the inner-main channel and is discharged from the top, and then enters the inner swirl and passes through the first-stage oil-phase channel 1161 in the first-stage inner bridge channel 116, and finally enters the oil-casing annulus through the first-stage oil-phase convergence inlet. This is the second-stage separation process. The remaining part of the unseparated mixed phase enters the third-stage hydrocyclone module 3 through the second-stage mixed-phase channel 2133 in the second-stage inner bridge channel 213, and then enters the third-stage spiral channel 301 to obtain sufficient tangential velocity and undergoes final separation inside the third-stage outer shell 302. Part of the oil phase is separated and passes through the second-stage oil-phase channel 2131 in the second-stage inner bridge channel 213, and then enters the oil-casing annulus through the second-stage oil-phase convergence inlet 2132, so as to converge with the previously separated oil phase through the 1032 oil-phase channel in the outer bridge channel 103 and be discharged from the oil-phase outlet 1021. Some of the unseparated oil phase adheres to the inverted cone and is sucked into the inner-branch channel in the cone by the diversion groove, then enters the inner-main channel and is discharged from the top, so as to enter the inner swirl and pass through the second-stage oil-phase channel 2131 in the second-stage inner bridge channel 213, and then enter the oil-casing annulus through the second-stage oil-phase convergence inlet 2132. This is the third-stage separation process.

[0036] The explosion diagram of the downhole oil-water multi-stage swirl purification device for simultaneous injection and production in the same well is as Figure 2 shown. The downhole oil-water multi-stage swirl purification device for simultaneous injection and production in the same well consists of a first-stage swirl module 1, a second-stage swirl module 2, and a third-stage swirl module 3.

[0037] The sectional view and partial enlarged view of the first-stage cyclone module are as Figure 3 shown. The oil-water mixture enters the first-stage cyclone from the outer feed port 1011 through the feed channel 1031 in the outer bridge channel 103 and then through the inner feed port 1051. After passing through the first-stage spiral flow channel 104, it obtains sufficient tangential velocity and undergoes preliminary separation inside the first-stage outer shell 105. Part of the oil phase is separated and discharged through the oil-phase outlet 1021. Some unseparated oil phase adheres to the inverted cone and is sucked into the flow channel between the cone section and the column section and discharged from the top, thus entering the inner swirl flow and being discharged through the oil-phase outlet 1021. The remaining unseparated mixed phase enters the next-stage separation through the first-stage mixed-phase channel 1163 in the first-stage inner bridge channel 116.

[0038] The partial explosion view of the first-stage cyclone module is as Figure 4 shown. It includes the outer bridge channel 103 and the first-stage spiral flow channel 104. The outer bridge channel 103 is provided with a feed channel 1031 and an oil-phase channel 1032 to prevent the separated oil phase and the mixed phase from interfering with each other. The first-stage inverted cone, the second-stage inverted cone, and the third-stage inverted cone are all connected to each other by multiple inverted cone segments through the snap ring 1081. Each inverted cone segment is integrally composed of a guide platform 1082, a cone body, and a guide groove. The guide platform is in the shape of a truncated cone, and the truncated cone is evenly distributed with corrugated edges around its body. The top of the guide platform is provided with a snap ring 1081; the guide groove 1086 is a truncated cone-shaped groove at the bottom of the cone body, and the inner wall of the truncated cone-shaped groove is evenly distributed with corrugated grooves around its body. The guide groove has a snap-ring groove 1084; there is an axial inner-cone main flow channel 1083 in the guide platform and the cone body. Adjacent inverted cone segments are connected by inserting the guide platform into the guide groove and the snap ring into the snap-ring groove. After each corrugated edge is inserted into the corresponding corrugated groove, the corrugated edge and the corrugated groove form a guide flow channel, and each guide flow channel is connected to the inner-cone main flow channel 1083 through an inner-cone branch flow channel 1085. The overall appearance, partial sectional view, and explosion view of the inverted cone of the first-stage cyclone module are as Figure 5 shown. The top section 106 of the first-stage inverted cone, the upper cone section 107 of the first-stage inverted cone, the middle cone section 108 of the first-stage inverted cone, the lower cone section 109 of the first-stage inverted cone, the top of the first-stage inverted cone column section 110, the upper column section 111 of the first-stage inverted cone, the middle column section 112 of the first-stage inverted cone, the lower column section 113 of the first-stage inverted cone, the bottom of the first-stage inverted cone column section 114, and the bottom section 115 of the first-stage inverted cone are all connected to each other through the snap ring 1081 and the snap-ring groove 1084. Some unseparated oil phase adheres to the inverted cone and is sucked into the inner-cone branch flow channel 1085 through the guide groove 1086 between the cone section and the column section, and then enters the inner-cone main flow channel 1083 and is discharged from the top.

[0039] The overall appearance and sectional view of the second-stage cyclone module are as Figure 6As shown, some incompletely separated mixed phases enter the secondary helical flow channel 201 and obtain sufficient tangential velocity, and are separated again inside the secondary housing 202. Some unseparated oil phases adhere to the inverted cone and are sucked into the inner branch channel of the cone through the diversion groove between the cone section and the column section, then enter the inner main channel of the cone and are discharged from the top. The remaining unseparated mixed phases enter the next stage of separation through the secondary inner bridge channel 213.

[0040] The explosion diagram of the secondary cyclone module is as Figure 7 shown. Some unseparated mixed phases enter the tertiary cyclone module 3 from the secondary mixed phase channel 2133 in the secondary inner bridge channel 213. Part of the oil phase in the tertiary cyclone module 3 is separated and passes through the secondary oil phase channel 2131 in the secondary inner bridge channel 213, and then enters the oil jacket annulus through the secondary oil phase inlet 2132. The top section 203 of the secondary inverted cone, the upper cone section 204 of the secondary inverted cone, the middle cone section 205 of the secondary inverted cone, the lower cone section 206 of the secondary inverted cone, the top 207 of the secondary inverted cone column section, the upper column section 208 of the secondary inverted cone, the middle column section 209 of the secondary inverted cone, the lower column section 210 of the secondary inverted cone, the bottom 211 of the secondary inverted cone column section, and the bottom section 212 of the secondary inverted cone are all connected to each other by snap rings. Some unseparated oil phases adhere to the inverted cone and are sucked into the inner branch channel of the cone through the diversion groove between the cone section and the column section, then enter the inner main channel of the cone and are discharged from the top.

[0041] The overall appearance and cross-sectional view of the tertiary cyclone module 3 are as Figure 8 shown. The tertiary inverted cone consists of the top section 303 of the tertiary inverted cone, the upper cone section 304 of the tertiary inverted cone, the middle cone section 305 of the tertiary inverted cone, the lower cone section 306 of the tertiary inverted cone, the top 307 of the tertiary inverted cone column section, the upper column section 308 of the tertiary inverted cone, the middle column section 309 of the tertiary inverted cone, the lower column section 310 of the tertiary inverted cone, the bottom 311 of the tertiary inverted cone column section, and the bottom section 312 of the tertiary inverted cone. Some unseparated mixed phases enter the tertiary helical flow channel 301 and obtain sufficient tangential velocity, and are finally separated inside the tertiary housing 302. Part of the oil phase is separated and enters the secondary inner bridge channel 213. Some unseparated oil phases adhere to the inverted cone and are sucked into the inner branch channel of the cone through the diversion groove between the cone section and the column section, then enter the inner main channel of the cone and are discharged from the top, thus entering the inner swirl and finally entering the secondary inner bridge channel 213. The explosion diagram of the tertiary cyclone module is as Figure 9 shown. Some unseparated oil phases adhere to the inverted cone and are sucked into the inner branch channel of the cone through the diversion groove between the cone section and the column section, then enter the inner main channel of the cone and are discharged from the top.

[0042] This kind of device is designed with a compact structure. The primary spiral flow channel initially separates the oil phase and the water phase. The mixed phase containing a small amount of oil at the bottom outlet after separation accumulates at the bottom of the hydrocyclone and enters the secondary cyclone separation through the bridge channel. The oil phase accumulates above the primary hydrocyclone and is discharged through the oil phase outlet. The flow channel in the inverted cone is used to suck the oil phase on the inverted cone surface and the oil phase that has not entered the inner swirl into the central flow channel inside the inverted cone, and transports it upward to the inner swirl and finally discharges from the oil phase outlet. The secondary variable-size cyclone separator sends the mixed phase that has not been completely separated into the tertiary cyclone module for re-separation. The separated oil phase enters the oil casing annulus through the bridge channel and finally discharges from the oil phase outlet. The tertiary variable-size cyclone separator finally separates the oil-containing mixed liquid at the bottom outlet that has not been completely separated in the previous two stages. The separated oil phase enters the oil casing annulus through the bridge channel and finally discharges at the oil phase outlet. The present invention can achieve the step-by-step efficient separation of the oil-water two-phase medium, greatly improving the economic benefits. At the same time, through the design of multi-stage separation, special inverted cone structure and special flow channels, the separation performance of the device itself is greatly improved. It is a high-efficiency separation device for multi-phase media applicable to downhole, with high working efficiency and good separation effect, which is beneficial to the sustainable development of oil fields and has high practicality.

[0043] The present invention has three cyclone modules. Through the spiral flow channel and the specially designed central flow channel inside the inverted cone, the oil-water separation is carried out to the end. The primary, secondary and final separations are completed in the primary, secondary and tertiary cyclone modules respectively, and are connected by a bridge channel in between. The oil phase accumulates above each stage of the cyclone and enters the oil phase outlet for discharge. Part of the mixed phase that has not been completely separated adheres to the inverted cone, and the oil phase is sucked in through the flow channel and transported upward to the inner swirl, and then discharged through the oil phase outlet. The water phase accumulates at the bottom of the cyclone and is discharged. The present invention innovatively uses an inverted cone and a three-stage separation system, and further enhances the oil-water separation efficiency through the internal flow channel, realizing efficient oil-water two-phase separation.

Claims

1. A downhole oil-water multi-stage cyclone purification device for co-well injection and production, characterized in that: This downhole oil-water multi-stage cyclone purification device for co-production injection and production includes a general housing, an end cap, a first-stage cyclone module, a second-stage cyclone module, and a third-stage cyclone module. The first-stage cyclone module, the second-stage cyclone module, and the third-stage cyclone module are connected in sequence from top to bottom and arranged inside the general housing to form a three-stage variable-size composite inverted-cone type oil-water separation device. The end cap is arranged at the upper port of the general housing, and the end cap has an oil-phase outlet. The upper end of the general housing is evenly distributed with external feed ports. The first-stage cyclone module includes an external bridge channel, a first-stage housing, a first-stage spiral channel, a first-stage inverted cone, and a first-stage internal bridge channel. The first-stage spiral channel and the first-stage inverted cone are arranged at intervals inside the first-stage housing. A gap channel is arranged between the first-stage spiral channel and the end cap. The first-stage spiral channel is provided with a central hole. The lower end of the first-stage housing is connected to the first-stage internal bridge channel. The upper end of the first-stage internal bridge channel is welded to the bottom section of the first-stage inverted cone. The first-stage internal bridge channel has a first-stage oil-phase confluence inlet communicating with the oil-casing annulus. The external bridge channel is cylindrical. Radial feed channels are evenly arranged on the circumferential direction of the cylindrical wall of the external bridge channel. Oil-phase channels are evenly arranged on the axial direction of the cylindrical wall of the external bridge channel. The external bridge channel is threadedly connected to the general housing and is located between the general housing and the outside of the first-stage housing. The external bridge channel is in tight fit with the first-stage housing. The first-stage housing is evenly provided with internal feed ports. Each external feed port, feed channel, and internal feed port corresponds to each other. The first-stage cyclone module is connected to the second-stage cyclone module through the first-stage internal bridge channel. The second-stage cyclone module is connected to the third-stage cyclone module through the second-stage internal bridge channel. The third-stage spiral channel of the third-stage cyclone module has an annular sealing partition. The annular sealing partition has an external thread and is threadedly connected to the general housing. The annular sealing partition divides the oil-casing annulus formed between the first-stage cyclone module, the second-stage cyclone module, and the third-stage cyclone module and the general housing into two parts. The second-stage cyclone module includes a second-stage housing, a second-stage spiral channel, a second-stage inverted cone, and a second-stage internal bridge channel. The second-stage spiral channel and the second-stage inverted cone are arranged at intervals inside the second-stage housing. The second-stage spiral channel is provided with a central hole. The second-stage internal bridge channel has a second-stage oil-phase confluence inlet communicating with the oil-casing annulus. The second-stage internal bridge channel also has a second-stage mixed-phase channel and a second-stage oil-phase channel. The second-stage spiral channel is connected to the first-stage internal bridge channel by welding. The second-stage housing is connected to the second-stage spiral channel by threading. The second-stage internal bridge channel is threadedly connected to the second-stage housing. The upper end of the second-stage internal bridge channel is welded to the bottom section of the second-stage inverted cone. The lower end of the second-stage internal bridge channel is connected to the third-stage spiral channel by welding. The third-stage cyclone module includes a third-stage housing, a third-stage spiral channel, and a third-stage inverted cone. The third-stage spiral channel and the third-stage inverted cone are arranged at intervals inside the third-stage housing. The third-stage spiral channel is provided with a central hole. The third-stage spiral channel is threadedly connected to the third-stage housing. The third-stage spiral channel is connected to the second-stage internal bridge channel by welding. The bottom section of the third-stage inverted cone is connected to the third-stage housing by welding.

2. The downhole oil-water multi-stage cyclone purification device for simultaneous injection and production in the same well according to claim 1, characterized in that: The described first-stage inverted cone, second-stage inverted cone, and third-stage inverted cone are each formed by connecting multiple inverted cone segments to each other through snap rings. Each inverted cone segment is integrally composed of a flow guiding platform, a cone body, and a flow guiding groove. The flow guiding platform is frustum-shaped, with corrugated ribs evenly distributed around the frustum. A snap ring is provided at the top of the flow guiding platform. The flow guiding groove is a frustum-shaped groove at the bottom of the cone body. Corrugated grooves are evenly distributed around the inner wall of the frustum-shaped groove. The flow guiding groove has a snap ring groove. An axial inner cone main flow channel is provided in the flow guiding platform and the cone body. Adjacent inverted cone segments are connected by inserting the flow guiding platform into the flow guiding groove and snapping the snap ring into the snap ring groove. After each corrugated rib is inserted into the corresponding corrugated groove, the corrugated rib and the corrugated groove form a flow guiding channel, and each flow guiding channel is connected to the inner cone main flow channel through an inner cone branch flow channel.

3. The downhole oil-water multi-stage cyclone purification device for simultaneous injection and production in the same well according to claim 2, characterized in that: The described first-stage inner bridge channel includes an outer cylinder and an inner column arranged coaxially. The first-stage outer shell is threadedly connected to the annular space between the outer cylinder and the inner column. The top plate of the second-stage spiral flow channel is fixed to the outer cylinder and closes the bottom of the annular space. The first-stage oil phase channel in the inner column communicates with the annular space, and the annular space communicates with the first-stage oil phase inlet. The inner column also has a first-stage mixed phase channel. The first-stage oil phase channel communicates with the central hole of the second-stage spiral flow channel through the central hole of the top plate of the second-stage spiral flow channel, and the first-stage mixed phase channel communicates with the second-stage outer shell through the central hole of the top plate of the second-stage spiral flow channel.

4. The downhole oil-water multi-stage cyclone purification device for simultaneous injection and production in the same well according to claim 3, wherein: The described first-stage spiral flow channel is connected to the first-stage outer shell by threads; the first-stage inverted cone is formed by connecting the first-stage inverted cone top segment, first-stage inverted cone upper cone segment, first-stage inverted cone middle cone segment, first-stage inverted cone lower cone segment, first-stage inverted cone column top segment, first-stage inverted cone upper column segment, first-stage inverted cone middle column segment, first-stage inverted cone lower column segment, first-stage inverted cone column bottom segment, and first-stage inverted cone bottom segment to each other through corresponding snap rings and snap ring grooves; the first-stage inner bridge channel is connected to the second-stage spiral flow channel by welding.

5. The downhole oil-water multi-stage cyclone purification device for simultaneous injection and production in the same well according to claim 4, characterized in that: The described second-stage inverted cone is formed by connecting the second-stage inverted cone top segment, second-stage inverted cone upper cone segment, second-stage inverted cone middle cone segment, second-stage inverted cone lower cone segment, second-stage inverted cone column top segment, second-stage inverted cone upper column segment, second-stage inverted cone middle column segment, second-stage inverted cone lower column segment, second-stage inverted cone column bottom segment, and second-stage inverted cone bottom segment to each other through snap rings.

6. The downhole oil-water multi-stage cyclone purification device for simultaneous injection and production in the same well according to claim 5, characterized in that: The described third-stage inverted cone is formed by connecting the third-stage inverted cone top segment, third-stage inverted cone upper cone segment, third-stage inverted cone middle cone segment, third-stage inverted cone lower cone segment, third-stage inverted cone column top segment, third-stage inverted cone upper column segment, third-stage inverted cone middle column segment, third-stage inverted cone lower column segment, third-stage inverted cone column bottom segment, and third-stage inverted cone bottom segment to each other through snap rings.

7. The downhole oil-water multi-stage cyclone purification device for simultaneous injection and production in the same well according to claim 6, characterized in that: The oil jacket annulus corresponding to the first-stage swirl module and the second-stage swirl module, the oil phase channel of the outer bridge channel, the clearance flow channel between the first-stage spiral flow channel and the end cover, and the oil phase outlet constitute an oil liquid upward channel.

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