A downhole oil-water cyclone separation component and a device and method using the same

Abstract

A downhole oil-water cyclone separation component and an apparatus and method for using the same. The invention is characterized in that: the separation component comprises a primary cyclone separation module, a secondary cyclone expansion module, and a micro-cyclone fine separation module; the cyclone separation module is used for preliminary separation of oil-water mixtures; the cyclone expansion module is used for separating oil-water mixtures that have not been separated by the cyclone separation module when the liquid inflow is high; the micro-cyclone fine separation module is used for completely separating small-particle oil droplets contained in the water phase after preliminary separation by the cyclone separation module and the cyclone expansion module; the separation device using the component adopts a series-parallel separation method, which can increase the processing capacity while separating fine oil droplets, thereby improving the processing accuracy, ensuring the stability of the cyclone liquid inflow, and realizing the lifting of the oil phase and the reinjection of the water phase in a limited space, and can be applied to various working conditions under high processing capacity of the same-well injection and production process in the oil field.

Description

Technical Field

[0001] The present disclosure relates to the field of downhole same-well injection and production, and in particular to a downhole oil-water cyclone separation device applied to downhole high water content conditions in oil fields. Background Art

[0002] At present, my country's major oil fields, such as Daqing Oilfield and Shengli Oilfield, have entered the middle and late stages of oilfield development. Most oil wells are produced by water injection. Not only is the water injection cost very high, but most of the water is also produced along with the oil during production, which also results in high oil production costs, significantly reducing the economic benefits of the oilfield. In response to the high liquid inflow rate in oilfields, most existing technologies use parallel same-stage cyclone separators to increase the liquid inflow rate. For example, my country's patent: Multi-stage oil-water separation and same-well injection and production device in a horizontal wellbore, patent number: CN202011286616.1 discloses a horizontal multi-stage oil-water separation device that uses a multi-stage parallel method for downhole oil-water separation. From the content disclosed in this document, it can be seen that although the multi-stage parallel method greatly improves the processing capacity, the separation accuracy of the parallel cyclone structure is low, especially the processing capacity of fine oil droplets is poor, and it is impossible to achieve both increased processing capacity and guaranteed processing accuracy. Summary of the Invention

[0003] In order to solve the technical problems mentioned in the background technology, this specification provides a downhole oil-water cyclone separation component and a specific technical solution of the device and method using the same, and gives several specific embodiments. The downhole oil-water cyclone separation device provided by these specific embodiments can increase the processing capacity while separating out fine oil droplets, thereby improving the processing accuracy. In addition, the device can also be connected in series with more secondary cyclone expansion modules according to the liquid inlet volume of the actual working conditions. In addition, the inverted cone structure of the secondary cyclone fixer in the secondary cyclone expansion module can evenly divert the oil-water mixture to the four secondary cyclones. The various innovative designs adopted ensure the processing accuracy while taking into account the processing capacity.

[0004] One or more embodiments of this specification are implemented according to the following scheme:

[0005] First embodiment:

[0006] A downhole oil-water cyclone separation assembly, including a primary cyclone separation module, is unique in that:

[0007] The primary cyclone separation module 1 is provided with a cross-flow channel 101, a primary connecting ring 102, a primary annular channel 103, a primary central pipe 104, a primary spiral flow channel holder 105, a primary cyclone holder 106, a primary spiral flow channel 107, a primary cyclone 108, a primary central pipe 109 and a primary underflow collector (110).

[0008] The cross-flow channel 101 is cylindrical in shape as a whole, includes a total overflow port 1011 and an oil-water inlet 1012 , and has a retaining ring 1013 .

[0009] An overflow hole 1031 and a primary center pipe connection port 1032 are provided at one end of the primary annular channel 103 , and a primary overflow cavity 1033 and a primary cyclone separation unit installation pipe 1034 are provided inside the primary annular channel 103 .

[0010] The first-stage spiral flow channel holder 105 has a plurality of circumferentially threaded first-stage spiral flow channel fixing holes 1051 and a first-stage central tube first connection hole 1052 with a thread at the center of the circle; the first-stage cyclone holder 106 has a plurality of circumferentially threaded first-stage cyclone fixing holes 1061 and a second first-stage central tube second connection hole 1062 at the center of the circle.

[0011] An overflow channel 1071 is provided inside the first-level spiral flow channel 107 ; a cyclone chamber 1081 is provided inside the first-level cyclone 108 ; and an oil-water channel 1091 is provided inside the first-level central pipe 109 .

[0012] The first-stage underflow collector 110 is provided with a plurality of circumferential first-stage underflow port fixing holes 1101 and a first-stage central pipe fixing hole 1102 at the center of the circle, and a first-stage overflow channel 1103 on the outside.

[0013] The cross-flow channel 101 is nested with the limiting ring 1021 on the first-level connecting ring 102 via an internal retaining ring 1013; the first-level connecting ring 102 is connected to the first-level annular channel 103 below via threads; the first-level central pipe 104 connects the first-level annular channel 103 and the first-level spiral flow channel holder 105 via outer threads; the first-level spiral flow channel 107 is connected to the first-level spiral flow channel fixing hole 1051 on the first-level spiral flow channel holder 105 via threads at the top, and is embedded into the first-level cyclone 108 by fitting with the hole at the bottom; the first-level cyclone 108 and the first-level central pipe 109 are threadedly connected to the first-level cyclone fixing hole 1061 and the second connecting hole 1062 of the first-level central pipe; the first-level annular channel 103 is threadedly connected to the first-level underflow collector 110.

[0014] The primary overflow chamber 1033 is communicated with the main overflow port 1011 .

[0015] The oil-water mixture in the primary cyclone separation module flows along the following path:

[0016] It enters the primary central pipe 104 from the oil-water inlet 1012 and then splits into two flow paths; under the first path, it enters the cyclone chamber 1081 for primary cyclone separation, and the separated oil enters the primary overflow chamber 1033 through the overflow channel 1071; under the second path, it flows into the primary central pipe 109.

[0017] The downhole oil-water cyclone separation component is based on the first embodiment and adds technical optimization means to obtain the second embodiment:

[0018] The assembly further comprises at least one secondary cyclone expansion module 2 .

[0019] The secondary cyclone expansion module 2 is provided with a secondary annular channel 201 , a secondary central pipe 202 , a secondary spiral flow channel holder 203 , a secondary cyclone holder 204 , a secondary spiral flow channel 205 , a secondary cyclone 206 and a secondary underflow collector 207 .

[0020] The secondary annular channel 201 is provided with a secondary overflow chamber 2011 , a secondary center pipe threaded connection hole 2012 , a secondary bottom flow chamber 2013 and a secondary cyclone separation unit installation pipe 2014 .

[0021] The secondary central tube 202 is a hollow tubular structure with external threads; the secondary spiral flow channel holder 203 has a plurality of circumferentially threaded secondary spiral flow channel fixing holes and a threaded secondary central tube connecting hole at the center thereof.

[0022] The secondary cyclone holder 204 is provided with a plurality of circumferential secondary cyclone fixing holes 2041 with threads and an inverted cone 2042 at the center.

[0023] An overflow channel 2051 is provided inside the secondary spiral flow channel 205 ; a secondary cyclone chamber 2061 is provided inside the secondary cyclone 206 ; and a plurality of annular secondary underflow port fixing holes 2071 , a secondary overflow channel 2072 and a secondary underflow channel 2073 are provided inside the secondary underflow collector 207 .

[0024] The secondary annular channel 201 is connected to the primary underflow collector 110 via threads; the secondary central tube 202 connects the secondary annular channel 201 and the secondary spiral flow channel holder 203 via outer threads; the secondary cyclone holder 204 is connected to the secondary annular channel 201 via external threads; the secondary spiral flow channel 205 is connected to the secondary spiral flow channel holder 203 via threads; the secondary cyclone 206 is connected to the secondary cyclone holder 204 via external threads at the top; the secondary underflow collector 207 connects the secondary annular channel 201 and the micro-cyclone annular channel 301 via internal threads; the secondary underflow channel 2073 is connected to the secondary underflow chamber 2013; and the secondary overflow channel 2072 is connected to the secondary overflow chamber 2011.

[0025] The first-level cyclone separation module and the second-level cyclone expansion module are connected together through the threads on the first-level underflow collector 110. After the connection, the first-level central pipe 109 and the second-level central pipe connection port 2021 are connected, and the second-level overflow chamber 2011, the first-level overflow chamber 1033 and the total overflow port 1011 are interconnected; the total overflow port 1011 is used to discharge the final oil phase.

[0026] The oil-water mixture entering the secondary cyclone expansion module flows along the following path:

[0027] After entering through the primary central pipe 109 and the secondary central pipe connection port 2021, it enters the secondary cyclone 206 for secondary cyclone separation. The separated oil phase enters the secondary overflow chamber 2011 through the secondary overflow channel 2072, and the water phase enters the secondary underflow channel 2073.

[0028] More secondary cyclone expansion modules can be connected in series according to the liquid inlet volume of actual working conditions.

[0029] The downhole oil-water cyclone separation component is based on the second embodiment and adds technical optimization means to obtain the third embodiment:

[0030] The assembly further comprises a micro-cyclone fine separation module 3 .

[0031] The micro-cyclone fine separation module includes a micro-cyclone annular channel 301 , a micro-cyclone holder 302 , a micro-cyclone 303 , a three-stage connecting ring 304 and an underflow plate 305 .

[0032] A three-stage overflow channel 3011 and a three-stage underflow channel 3012 are constructed inside the micro-cyclone annular channel 301 .

[0033] The microcyclone holder 302 is a disc-shaped structure with two layers, the lower layer has several microcyclone fixing holes 3021 with threads, the upper layer has several overflow pipe fixing holes 3022, and the middle is a three-stage bottom flow cavity 3023.

[0034] A microcyclone overflow pipe 3031 , a microcyclone liquid inlet 3032 and a microcyclone bottom flow outlet 3033 are constructed inside the microcyclone 303 .

[0035] The structure of the tertiary connecting ring 304 is the same as that of the primary connecting ring 102 .

[0036] A micro-cyclone underflow port fixing hole 3051 and a total underflow port 3052 are constructed inside the underflow plate 305 .

[0037] The micro-cyclone annular channel 301 is connected to the secondary underflow collector 207 via external threads. The micro-cyclone holder 302 is connected to the micro-cyclone 303 via threads on the micro-cyclone fixing hole 3021 and the overflow pipe fixing hole 3022. The micro-cyclone holder 302 is connected to the internal threads of the micro-cyclone annular channel 301 via peripheral external threads. The underflow plate 305 is connected to the micro-cyclone annular channel 301 via threads on a tertiary connecting ring 304.

[0038] The secondary cyclone expansion module and the micro-cyclone fine separation module are connected together through the threads on the secondary underflow collector 207. After the connection, the secondary underflow chamber 2013 and the secondary underflow channel 2073 are connected, the secondary underflow channel 2073 and the tertiary underflow channel 3012 are connected, and the secondary overflow chamber 2011 and the secondary overflow channel 2072 are connected.

[0039] The oil-water mixture entering the micro-cyclone fine separation module flows along the following path:

[0040] The oil-water mixture reaching the micro-cyclone fine separation module is separated by secondary cyclone, the separated oil phase enters the secondary overflow channel 2072, and the separated water phase finally reaches the total bottom flow outlet 3052 for discharge.

[0041] By selecting any of the downhole oil-water cyclone separation assemblies described in the first to third embodiments according to actual operating conditions and configuring corresponding auxiliary components, a new downhole oil-water cyclone separation device can be constructed. After the downhole oil-water cyclone separation device is connected to a downhole process string for injection and production in the same well, the separated water phase is injected into the water phase reinjection port of the process string, and the separated oil phase is injected into the oil phase lift channel of the process string.

[0042] The above embodiment embodies a specific application of a new downhole oil-water cyclone separation method, which can be summarized as follows:

[0043] A first-stage cyclone separation module, several second-stage cyclone expansion modules connected in series, and a micro-cyclone fine separation module are sequentially connected to the downhole process string of the same well;

[0044] The primary cyclone separation module is used for the preliminary separation of the oil-water mixture;

[0045] The cyclone expansion module is located at the lower end of the primary cyclone separation module and is used to process the oil-water mixture that is not separated in time by the primary cyclone separation module when the liquid inflow is high;

[0046] The micro-cyclone fine separation module is used to perform secondary separation on the water phase obtained after the primary separation by the cyclone separation module and the cyclone expansion module, and completely separate the small-sized oil droplets contained in the water phase after the primary separation.

[0047] The at least one technical solution adopted in one or more embodiments of this specification can achieve the following beneficial effects:

[0048] First, the overall structure of this device utilizes a multi-stage cyclone module connected in series and parallel. This increases the device's processing capacity while enhancing the oil-water separation accuracy, saving oil extraction costs and improving applicability. This device is simple to connect, and when facing extremely high liquid inflows, more secondary cyclone expansion modules can be connected in series to cope with various operating conditions in the oil field.

[0049] Secondly, the inverted cone structure of the secondary cyclone holder in the secondary cyclone expansion module can evenly divert the oil-water mixture into four secondary cyclones, thereby improving separation efficiency and accuracy.

[0050] Thirdly, the overflow flow channel and underflow flow channel used can transport the separated oil and water to the total overflow port and the total underflow port in the narrow space within the wellbore, ultimately realizing injection and production in the same well.

[0051] In addition, the micro-cyclone fine separation module used can perform secondary separation on the water phase separated by the primary cyclone separation module and the secondary cyclone expansion module, thereby reducing the oil concentration of the reinjection water and improving the recovery efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of this specification, the following is a brief introduction to the drawings required for use in the embodiments: the drawings described below are only some of the embodiments recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0053] Figure 1 This is a cross-sectional view of the downhole cyclone separation device.

[0054] Figure 2 This is the overall exploded view of the downhole cyclone separation device.

[0055] Figure 3 This is the exploded diagram of the first-stage cyclone separation module.

[0056] Figure 4 Cross-flow channel cross-sectional view.

[0057] Figure 5 This is the appearance of the first-level ring channel.

[0058] Figure 6 This is a cross-sectional view of the first-level annular channel.

[0059] Figure 7 This is a cross-sectional view of the first-stage spiral flow channel holder.

[0060] Figure 8 This is the appearance of the first-stage cyclone holder.

[0061] Figure 9 This is a cross-sectional view of the first-stage spiral flow channel.

[0062] Figure 10 This is the appearance of the first-stage cyclone.

[0063] Figure 11 This is the appearance diagram of the first-level central pipeline.

[0064] Figure 12 This is a cross-sectional view of the first-stage underflow collector.

[0065] Figure 13 This is a partial enlarged view of the flow channel of the first-stage cyclone separation module.

[0066] Figure 14 This is the exploded diagram of the secondary swirl expansion module.

[0067] Figure 15 This is a cross-sectional view of the secondary annular channel.

[0068] Figure 16 This is the appearance diagram of the secondary cyclone holder.

[0069] Figure 17 This is a cross-sectional view of the secondary underflow collector.

[0070] Figure 18 This is a partial enlarged view of the overflow channel of the secondary swirl expansion module.

[0071] Figure 19 This is a partial enlarged view of the bottom flow channel of the secondary swirl expansion module.

[0072] Figure 20 Exploded view of the microcyclone fine separation module.

[0073] Figure 21 This is a cross-sectional view of the micro-vortex annular channel.

[0074] Figure 22 This is a cross-sectional view of the microcyclone holder.

[0075] Figure 23 This is the appearance of the microcyclone.

[0076] Figure 24 This is a cross-sectional view and a partially enlarged view of the microcyclone.

[0077] Figure 25 This is a cross-sectional view of the underflow plate.

[0078] In the figure, 1-first-stage cyclone separation module, 101-cross-flow channel, 1011-total overflow port, 1012-oil-water inlet, 1013-clamping ring, 102-first-stage connecting ring, 1021-limiting ring, 103-first-stage annular channel, 1031-overflow hole, 1032-first-stage center pipe connecting port, 1033-first-stage overflow cavity, 1034-first-stage cyclone separation unit installation pipe, 104-first-stage center pipe, 1041-liquid inlet, 105-first-stage spiral flow channel holder, 1051-first-stage spiral flow channel fixing hole, 1052-first-stage center pipe first Connecting hole, 106-first-level cyclone holder, 1061-first-level cyclone fixing hole, 1062-first-level center pipe second connecting hole, 107-first-level spiral flow channel, 1071-overflow channel, 108-first-level cyclone, 1081-cyclone chamber, 109-first-level center pipe, 1091-oil-water channel, 110-first-level underflow collector, 1101-first-level underflow port fixing hole, 1102-first-level center pipe fixing hole, 1103-first-level overflow channel; 2-second-level cyclone expansion module, 201-second-level annular channel, 2011-second-level overflow Cavity, 2012-secondary center pipe threaded connection hole, 2013-secondary underflow cavity, 2014-secondary cyclone separation unit installation pipe, 202-secondary center pipe, 2021-secondary center pipe connection port, 203-secondary spiral flow channel holder, 204-secondary cyclone holder, 2041-secondary cyclone fixing hole, 2042-inverted cone, 205-secondary spiral flow channel, 206-secondary cyclone, 2061-secondary cyclone cavity, 2062-inverted cone, 207-secondary underflow collector, 2071-secondary underflow port fixing hole, 2072-secondary Overflow channel, 2073-secondary underflow channel; 3-microcyclone fine separation module, 301-microcyclone annular channel, 3011-tertiary overflow channel, 302-microcyclone holder, 3021-microcyclone fixing hole, 3022-overflow pipe fixing hole, 3023-tertiary underflow cavity, 303-microcyclone, 3031-microcyclone overflow pipe, 3032-microcyclone liquid inlet, 3033-microcyclone underflow outlet, 304-tertiary connecting ring, 305-underflow plate, 3051-microcyclone underflow outlet fixing hole, 3052-total underflow outlet. DETAILED DESCRIPTION

[0079] The technical solution provided in this disclosure is further described below with reference to the accompanying drawings:

[0080] The overall cross-sectional view of the downhole oil-water cyclone separation device is as follows: Figure 1 As shown, the oil-water mixture with high water content enters the device from the oil-water inlet 1012 for cyclone separation, the separated water phase is discharged from the total bottom flow outlet 3052 below, and the separated oil phase is lifted to the ground from the total overflow outlet 1011 above.

[0081] Exploded view of downhole oil-water cyclone separation device Figure 2 As shown, the device mainly consists of three parts: a primary cyclone separation module 1, a secondary cyclone expansion module 2 and a micro-cyclone fine separation module 3.

[0082] Figure 3 This is an exploded view of the first-level cyclone separation module 1, which mainly includes a cross-flow channel 101, a first-level connecting ring 102, a first-level annular channel 103, a first-level central pipe 104, a first-level spiral flow channel holder 105, a first-level cyclone holder 106, a first-level spiral flow channel 107, a first-level cyclone 108, a first-level central pipe 109, and a first-level underflow collector 110.

[0083] The cross-sectional view of the cross-flow channel 101 is as follows: Figure 4 As shown, the oil-water mixture with high water content enters the device through the oil-water inlet 1012, and the separated oil phase is lifted to the ground from the total overflow port 1011. The cross-flow channel cooperates with the limiting ring 1021 and the retaining ring 1013 on the primary connecting ring 102 to achieve the purpose of connecting with the primary annular channel 103.

[0084] The appearance of the first-level ring channel is as follows Figure 5 As shown, the internal threaded structure converts the rotational force into an axial force and applies it to the limiting ring 1021 and the retaining ring 1013 to complete the connection and fixation of the cross-flow channel 101 and the primary annular channel 103.

[0085] The cross-sectional view of the primary annular channel 103 is as follows: Figure 6 As shown, the oil phase separated by the first-stage cyclone separation module 1, the second-stage cyclone expansion module 2 and the micro-cyclone fine separation module 3 converges into the overflow chamber 1033 and then flows through the overflow hole 1031 and the total overflow port 1011 out of the device. The first-stage cyclone separation unit is installed inside the first-stage cyclone separation unit installation tube 1034.

[0086] The appearance and cross-sectional view of the first-stage spiral flow channel holder 105 are as follows: Figure 7 As shown, there are four primary spiral flow channel fixing holes 1051 evenly distributed in the circumferential direction inside the primary spiral flow channel for fixing the four primary spiral flow channels 107. The primary center tube 104 can be connected to the first primary center tube first connection hole 1052 at the center of the circle by threading.

[0087] The appearance of the first-stage cyclone holder 106 is shown in FIG. Figure 8As shown, there are four primary cyclone fixing holes 1061 evenly distributed in the circumferential direction inside the primary cyclone for fixing four primary cyclones 108 . The primary center tube 104 can be connected to the primary center tube second connecting hole 1062 at the center of the circle by screw threads.

[0088] Figure 9 It is a cross-sectional view of the primary spiral flow channel 107 , which is connected to the spiral flow channel holder 105 via threads, and the separated oil phase enters the primary overflow chamber 1033 through the internal overflow channel 1071 .

[0089] The appearance of the first-stage cyclone 108 is as follows Figure 10 As shown, the oil-water mixture enters the internal cyclone chamber 1081 through the spiral flow channel for cyclone separation.

[0090] The appearance of the first-level central pipeline 109 is as follows Figure 11 As shown, its upper end is connected to the first-stage cyclone holder through a thread.

[0091] The cross-sectional view of the first-stage underflow collector 110 is as follows: Figure 12 As shown, there are four primary underflow fixing holes 1101 evenly distributed in the circumferential direction inside the circumference for fixing four primary cyclones 108, and a primary central pipe fixing hole 1102 is located at the center of the circle.

[0092] A partial enlarged view of the flow channel of the first-stage cyclone separation module 1 is shown in the figure. Figure 13 As shown, a highly water-rich oil-water mixture first enters the oil-water inlet 1012, passes through the primary central pipe 104, and enters the primary cyclone 108 and the primary central pipeline 109. The oil-water mixture entering the primary cyclone 108 undergoes cyclonic separation. The oil phase rises through the overflow channel 1071 into the primary overflow chamber 1033 and then exits the device through the main overflow port 1011. The water phase then descends through the cyclone chamber 1081 into the secondary underflow chamber 2013. This completes the primary cyclonic separation process. The oil-water mixture entering the primary central pipeline 109 directly reaches the secondary cyclone expansion module 2.

[0093] The exploded view of the secondary cyclone expansion module 2 is as follows: Figure 14 As shown, the secondary cyclone expansion module 2 includes a secondary annular channel 201 , a secondary central tube 202 , a secondary spiral flow channel holder 203 , a secondary cyclone holder 204 , a secondary spiral flow channel 205 , a secondary cyclone 206 , and a secondary underflow collector 207 .

[0094] The cross-sectional view of the secondary annular channel 201 is as follows: Figure 15As shown, it is connected to the primary underflow collector 110 and the secondary underflow collector 207 via external threads. The oil phase separated by the micro-cyclone fine separation module 3 and the secondary cyclone expansion module 2 is lifted into the secondary overflow chamber 2011, where it merges with the oil phase in the primary overflow chamber 1033. The water phase separated by the primary cyclone separation module 1 enters the micro-cyclone fine separation module 3 through the secondary underflow chamber 2013. Four secondary cyclones 206 are evenly distributed within the secondary cyclone separation unit mounting tube 2014.

[0095] The appearance and cross-sectional view of the secondary cyclone holder 204 are as follows: Figure 16 As shown, there are four secondary cyclone fixing holes 2041 evenly distributed in the circumferential direction inside the secondary cyclone for fixing four secondary cyclones 206 . The mixed liquid passing through the secondary central tube 202 will be evenly distributed into the secondary cyclones 206 after passing through the inverted cone 2042 at the center of the circle.

[0096] The appearance and cross-sectional view of the secondary underflow collector 207 are as follows: Figure 17 As shown, there are four secondary underflow fixing holes 2071 evenly distributed in the annular direction inside the secondary cyclone, which are used to fix the four secondary cyclones 206. The water phase separated by the secondary cyclone expansion module 2 enters the microcyclone 303 through the secondary overflow channel 2072, and the oil phase separated by the microcyclone fine separation module 3 enters the secondary overflow chamber 2011 through the secondary underflow channel 2073.

[0097] A partial enlarged view of the overflow channel of the secondary swirl expansion module 2 is shown in the figure below: Figure 18 As shown, the oil-water mixture coming down from the primary central pipe 109 enters the secondary cyclone 206 through the secondary central pipe connection port 2021 for cyclone separation. The separated oil phase enters the secondary overflow chamber 2011 through the overflow channel 2051, and then merges with the oil phase in the primary overflow chamber 1033, and is finally discharged from the total overflow port 1011; the separated water phase passes through the secondary cyclone chamber 2061 and is transferred to the secondary bottom flow chamber 2013. The above is the secondary cyclone separation process.

[0098] A partial enlarged view of the bottom flow channel of the secondary swirl expansion module is shown in the figure. Figure 19 As shown, the water phase separated by the primary cyclone separation module 1 passes through the secondary underflow chamber 2013 to the secondary underflow channel 2073, then enters the tertiary underflow chamber 3023 through the tertiary underflow channel 3012. Finally, the water phases separated by the primary cyclone separation module 1 and the secondary cyclone expansion module 2 enter the tertiary microcyclone 303 for tertiary cyclone separation. The separated oil phase is lifted to the secondary overflow channel 2072, then passes through the secondary overflow chamber 2011 and the primary overflow chamber 1033 to the main overflow port 1011 and is lifted to the ground. The separated water phase then exits the device downward through the main underflow port 3052.

[0099] Exploded diagram of micro-cyclone fine separation module 3 Figure 20 As shown, it includes a micro-cyclone annular channel 301 , a micro-cyclone holder 302 , a micro-cyclone 303 , a three-stage connecting ring 304 , and an underflow plate 305 .

[0100] The cross-sectional view of the micro-cyclone annular channel 301 is as follows: Figure 21 As shown, the microcyclone holder 302 is connected to the external three-stage connecting ring 304 through internal and external threads. The appearance and cross-sectional view of the microcyclone holder 302 are as follows: Figure 22 As shown, the microcyclone 303 is connected to the microcyclone fixing hole 3021 through the external thread in the middle, and the microcyclone overflow pipe 3031 is directly inserted into the overflow pipe fixing hole 3022. The overflow pipe fixing hole 3022 is a stepped through hole, which has the functions of fixing, limiting and guiding liquid.

[0101] The appearance of the microcyclone 303 is shown in FIG. Figure 23 As shown, the middle thread is used to connect with the microcyclone holder 302. The cross-sectional view and partial enlarged view of the microcyclone 303 are shown in FIG. Figure 24 As shown, the water phase separated by the primary cyclone separation module 1 and the secondary cyclone expansion module 2 will enter the microcyclone 303 from the microcyclone liquid inlet 3032 for secondary cyclone. The separated oil phase and the oil phases in the secondary overflow chamber 2011 and the primary overflow chamber 1033 will converge at the total overflow port 1011 and be discharged from the device; the separated water phase will be discharged from the underflow plate 305 through the microcyclone underflow port 3033.

[0102] The cross-sectional view of the underflow plate 305 is as follows: Figure 25 As shown, the water phase separated by the primary cyclone separation module 1, the secondary cyclone expansion module 2 and the micro-cyclone fine separation module 3 will eventually enter the bottom flow plate 305 through the micro-cyclone bottom flow port fixed hole 3051, converge to the total bottom flow port 3052 and then be discharged from the device.

[0103] After the device is connected to the injection and production process string in an oilfield well, the oil-water mixture enters the primary cyclone separation module and the secondary cyclone expansion module for initial oil-water separation. The separated water phase then flows through a designed underflow collector and annular channel into the microcyclone fine separation module for secondary separation. The separated oil phase then flows through a flow channel to a central overflow port, where it is lifted to the surface. The separated water ultimately flows back to the central underflow port for injection into the ground.

[0104] The solution given in this specification utilizes the principle of parallel cyclones to increase processing capacity and series cyclones to improve separation accuracy, and performs multiple separations on the oil-water mixture with a high water content. While increasing the processing capacity, the oil-water separation accuracy of the device is enhanced. At the same time, an innovative design is made to the flow channel discharged into the device, which not only ensures the stability of the liquid inlet to the cyclone, but also realizes the lifting of the oil phase and the reinjection of the water phase in a limited space. It takes into account the separation accuracy while ensuring a high processing capacity, and enhances the applicability of the hydrocyclone in the same-well injection and production process.

Claims

1. A downhole oil-water cyclone separation assembly, comprising a primary cyclone separation module (1) and at least one secondary cyclone expansion module (2); The primary cyclone separation module (1) is provided with a cross-flow channel (101), a primary connecting ring (102), a primary annular channel (103), a primary central pipe (104), a primary spiral flow channel holder (105), a primary cyclone holder (106), a primary spiral flow channel (107), a primary cyclone (108), a primary central pipe (109), and a primary underflow collector (110); The cross-flow channel (101) is cylindrical in shape as a whole, includes a total overflow port (1011) and an oil-water inlet (1012), and has a clamping ring (1013); An overflow hole (1031) and a first-level central pipe connection port (1032) are provided at one end of the first-level annular channel (103); a first-level overflow cavity (1033) and a first-level cyclone separation unit installation pipe (1034) are provided inside the first-level annular channel (103); The first-stage spiral flow channel holder (105) is provided with a plurality of circumferentially threaded first-stage spiral flow channel fixing holes (1051) and a first-stage central tube first connecting hole (1052) with a thread at the center of the circle; the first-stage cyclone holder (106) is provided with a plurality of circumferentially threaded first-stage cyclone fixing holes (1061) and a second first-stage central tube second connecting hole (1062) at the center of the circle; An overflow channel (1071) is provided inside the first-stage spiral flow channel (107); a cyclone chamber (1081) is provided inside the first-stage cyclone (108); and an oil-water channel (1091) is provided inside the first-stage central pipe (109). The first-stage underflow collector (110) is provided with a plurality of circumferential first-stage underflow port fixing holes (1101) and a first-stage central pipe fixing hole (1102) at the center of the circle, and a first-stage overflow channel (1103) is provided on the outside. The cross-flow channel (101) is nested with the limiting ring (1021) on the first-level connecting ring (102) through an internal clamping ring (1013); the first-level connecting ring (102) is connected to the first-level annular channel (103) below through a thread; the first-level central tube (104) connects the first-level annular channel (103) and the first-level spiral flow channel holder (105) together through an outer thread; the first-level spiral flow channel (107) is connected to the first-level spiral flow channel fixing hole (1051) on the first-level spiral flow channel holder (105) through a thread at the top, and is embedded into the cyclone through the hole of the first-level cyclone (108) at the bottom; the first-level cyclone (108) and the first-level central pipe (109) are connected to the first-level cyclone fixing hole (1061) and the second connecting hole (1062) of the first-level central tube through a thread; the first-level annular channel (103) and the first-level underflow collector (110) are connected together through a thread; The primary overflow chamber (1033) and the main overflow port (1011) are in communication with each other; The oil-water mixture in the primary cyclone separation module flows along the following path: The oil enters the primary central pipe (104) from the oil-water inlet (1012) and then splits into two flow paths; the first path enters the cyclone chamber (1081) for primary cyclone separation, and the separated oil enters the primary overflow chamber (1033) through the overflow channel (1071); the second path flows into the primary central pipe (109); The secondary cyclone expansion module (2) is provided with a secondary annular channel (201), a secondary central tube (202), a secondary spiral flow channel holder (203), a secondary cyclone holder (204), a secondary spiral flow channel (205), a secondary cyclone (206) and a secondary underflow collector (207); in, The secondary annular channel (201) is provided with a secondary overflow chamber (2011), a secondary center pipe threaded connection hole (2012), a secondary bottom flow chamber (2013), and a secondary cyclone separation unit installation pipe (2014); The secondary central tube (202) is a hollow tubular structure with external threads; the secondary spiral flow channel holder (203) is internally provided with a plurality of circumferentially threaded secondary spiral flow channel fixing holes and a threaded secondary central tube connecting hole at the center of the circle; The secondary cyclone holder (204) is provided with a plurality of circumferential threaded secondary cyclone fixing holes (2041) and an inverted cone (2042) at the center of the circle; An overflow channel (2051) is provided inside the secondary spiral flow channel (205); a secondary cyclone chamber (2061) is provided inside the secondary cyclone (206); and a plurality of circumferential secondary bottom flow port fixing holes (2071), a secondary overflow channel (2072), and a secondary bottom flow channel (2073) are provided inside the secondary bottom flow collector (207); The secondary annular channel (201) is connected to the primary underflow collector (110) through a thread; the secondary central tube (202) connects the secondary annular channel (201) and the secondary spiral flow channel holder (203) through an outer thread; the secondary cyclone holder (204) is connected to the secondary annular channel (201) through an external thread; the secondary spiral flow channel (205) is connected to the secondary spiral flow channel holder (203) through a thread; the secondary cyclone (206) is connected to the secondary cyclone holder (204) through an external thread at the top; the secondary underflow collector (207) connects the secondary annular channel (201) and the micro-cyclone annular channel (301) through an internal thread; the secondary underflow channel (2073) is connected to the secondary underflow chamber (2013); and the secondary overflow channel (2072) is connected to the secondary overflow chamber (2011). The primary cyclone separation module and the secondary cyclone expansion module are connected together via threads on the primary underflow collector (110). After the connection, the primary central pipe (109) and the secondary central pipe connection port (2021) are connected, and the secondary overflow chamber (2011), the primary overflow chamber (1033) and the total overflow port (1011) are interconnected; the total overflow port (1011) is used to discharge the final oil phase; The oil-water mixture entering the secondary cyclone expansion module flows along the following path: After entering through the primary central pipe (109) and the secondary central pipe connection port (2021), it enters the secondary cyclone (206) for secondary cyclone separation, and the separated oil phase enters the secondary overflow chamber (2011) through the secondary overflow channel (2072), and the water phase enters the secondary underflow channel (2073); Its characteristics are: The assembly also includes a micro-cyclone fine separation module (3); The micro-cyclone fine separation module (3) comprises a micro-cyclone annular channel (301), a micro-cyclone holder (302), a micro-cyclone (303), a three-stage connecting ring (304), and an underflow plate (305); A three-stage overflow channel (3011) and a three-stage underflow channel (3012) are constructed inside the micro-cyclone annular channel (301); The microcyclone holder (302) is configured as a disc-shaped structure with two layers, the lower layer having a plurality of threaded microcyclone fixing holes (3021), the upper layer having a plurality of overflow pipe fixing holes (3022), and a three-stage bottom flow cavity (3023) in the middle; The microcyclone (303) is internally constructed with a microcyclone overflow pipe (3031), a microcyclone liquid inlet (3032), and a microcyclone bottom flow outlet (3033); The structure of the tertiary connecting ring (304) is the same as that of the primary connecting ring (102); A micro-cyclone bottom flow outlet fixing hole (3051) and a total bottom flow outlet (3052) are constructed inside the bottom flow plate (305); The micro-cyclone annular channel (301) is connected to the secondary underflow collector (207) via external threads; the micro-cyclone holder (302) is connected to the micro-cyclone (303) via threads on the micro-cyclone fixing hole (3021) and the overflow pipe fixing hole (3022); the micro-cyclone holder (302) is connected to the internal threads of the micro-cyclone annular channel (301) via peripheral external threads; the underflow plate (305) is connected to the micro-cyclone annular channel (301) via threads on a tertiary connecting ring (304); The secondary cyclone expansion module and the microcyclone fine separation module are connected together via threads on the secondary underflow collector (207). After the connection, the secondary underflow chamber (2013) and the secondary underflow channel (2073) are connected, the secondary underflow channel (2073) and the tertiary underflow channel (3012) are connected, and the secondary overflow chamber (2011) and the secondary overflow channel (2072) are connected. The oil-water mixture entering the micro-cyclone fine separation module flows along the following path: The oil-water mixture that reaches the micro-cyclone fine separation module is separated by secondary cyclone, and the separated oil phase enters the secondary overflow channel (2072), while the separated water phase finally reaches the total bottom flow outlet (3052) for discharge.

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