Gas lift enhanced oil-gas-water three-phase swirl separation device in the same well injection-production wellbore

Abstract

The present invention relates to a gas-lift enhanced oil-gas-water three-phase cyclone separation device in the injection-production wellbore of the same well. It is formed by connecting a gas-liquid separation module to an oil-water two-phase gas-lift high-efficiency separation module. The oil-water two-phase gas-lift high-efficiency separation module includes an upper outer sleeve, an oil-water separation cyclone, and an inverted cone. The gas-liquid separation module includes a bridge channel, a gas-liquid separation cyclone, a spiral flow channel with a screen, and a lower outer sleeve. The bridge channel is a cylinder with an inner cavity, and crescent holes are symmetrically arranged on the outer side of the inner cavity. The bridge channel is respectively connected to the upper outer sleeve and the lower outer sleeve. The lower outer sleeve is connected to the tubing collar. The bridge channel has a three-phase mixed liquid inlet hole, and its bottom end is connected to the gas-liquid separation cyclone. The gas-phase overflow pipe is provided with a spiral flow channel with a screen and a filter screen, and the top end of the gas-phase overflow pipe is short-connected to the central hole of the inverted cone base. The present invention promotes the efficient separation of the oil-water two-phase medium through gas-lift, reduces the lifting cost of the water-phase medium, alleviates the working pressure of the lifting pump, and greatly improves the economic benefits.

Description

Technical Field

[0001] The present invention relates to the field of downhole oil-water separation in petrochemical industry, and particularly to a gas-lift enhanced oil-gas-water three-phase cyclone separation device in an injection-production wellbore of the same well. Background Art

[0002] In oilfield exploitation, the produced fluid is mainly a three-phase mixture of oil, gas and water. For high water cut oilfields, the water cut of the produced fluid exceeds 98%, the liquid-oil ratio is very high, the system back pressure is large, the gathering and transportation efficiency is low, and the separation efficiency is not good. In order to ensure the crude oil production, the oilfield has increased the production capacity investment, resulting in the produced water having to go through a long cycle, and the energy consumption of the gathering and transportation system increases. Controlling water, stabilizing oil, saving energy and increasing efficiency have become the main problems in improving the economic benefits of high water cut oilfields. In the current injection-production technology of the same well, due to the uncertainty brought by the complex downhole working conditions, conditions such as containing gas make it difficult to improve the oil-water separation efficiency. Therefore, it is very necessary to develop a device that can use the downhole gas phase medium to improve the separation performance of downhole three-phase media.

[0003] For a Chinese invention patent of an oil-gas-water three-phase separator, the patent number is: ZL202010261383.3. Although the device designed in this patent separates the gas-liquid two-phase medium through a sprinkling device and a partition board, there are still many deficiencies. First, the structure is too complex, and a motor is required to drive the sprinkling device to rotate, increasing the cost. Second, the separation efficiency of the gas phase is low, and there is still a small amount of gas phase remaining in the liquid phase. Although the device designed in this patent realizes the separation of the oil-water two-phase through a spiral flow channel, the separation efficiency is low, and the separated water phase still needs to be collected and processed before it can be used. There is a need for a gas-lift enhanced oil-gas-water three-phase cyclone separation device in an injection-production wellbore of the same well to achieve efficient separation of downhole multi-phase media. Summary of the Invention

[0004] The purpose of the present invention is to provide a gas-lift enhanced oil-gas-water three-phase cyclone separation device in an injection-production wellbore of the same well, which is used to solve the problem of low efficiency of the existing oil-gas-water three-phase flow separation device.

[0005] The technical solution adopted by the present invention to solve its technical problems is as follows: This gas-lift enhanced oil-gas-water three-phase cyclone separation device in the same well injection-production wellbore is formed by connecting a gas-liquid separation module to the upper end of an oil-water two-phase gas-lift high-efficiency separation module. The oil-water two-phase gas-lift high-efficiency separation module includes an upper outer sleeve, an oil-water separation cyclone, and an inverted cone. The gas-liquid separation module includes a bridge channel, a tubing collar, a water outlet pipe, a gas-liquid separation cyclone, a spiral flow channel with a screen, and a lower outer sleeve; the bridge channel is a cylinder with an inner cavity, two crescent holes are symmetrically arranged on the outer side of the inner cavity, both crescent holes penetrate the bridge channel along the axial direction, the lower side wall of the bridge channel is threadedly connected to the lower outer sleeve, and its upper side wall is threadedly connected to the upper outer sleeve; the lower end of the lower outer sleeve is threadedly connected to the tubing collar; a three-phase mixed liquid inlet hole is opened on the outer wall of the bridge channel, and its bottom central hole is threadedly connected to the top of the gas-liquid separation cyclone; the gas-phase overflow pipe is provided with a spiral flow channel with a screen and a filter screen, the filter screen is arranged at the bottom of the gas-phase overflow pipe, the spiral flow channel with a screen is located above the filter screen, the gas-phase overflow pipe passes through the bridge channel upward, and the top end of the gas-phase overflow pipe is short-connected to the central hole of the inverted cone base; the water outlet pipe passes through the crescent hole, the bottom pipe outlet of which is embedded and short-connected to the small hole at the bottom end of the lower outer sleeve, and the top pipe inlet of which is embedded and short-connected to the water outlet of the oil-water separation cyclone.

[0006] In the above solution, the oil-water two-phase gas-lift high-efficiency separation module further includes a casing collar, a spiral flow channel with a top cover, and an inverted cone. A sealing plate is provided at the lower end of the casing collar, and the center of the sealing plate has a central hole at the bottom of the casing collar. The spiral flow channel with a top cover is formed by the top cover and the spiral flow channel being arranged at intervals outside the oil-phase overflow pipe. The top cover is located above the spiral flow channel. The lower port of the casing collar is threadedly connected to the upper step of the top cover, and the central hole at the bottom of the casing collar is short-connected to the oil-phase overflow pipe; the top cover is a cylinder with steps at both the upper and lower ends, and its outer wall and the steps at both the upper and lower ends have external threads. The outer wall of the top cover is threadedly connected to the upper outer sleeve, and the lower step of the top cover is threadedly connected to the oil-water separation cyclone; the bottom base of the inverted cone is threadedly connected to the bottom of the oil-water separation cyclone; the oil-water separation cyclone is located inside the upper outer sleeve, the inverted cone is located inside the oil-water separation cyclone, the inverted cone is located directly below the oil-phase overflow pipe, and the inverted cone is arranged at intervals with the oil-phase overflow pipe.

[0007] In the above solution, the upper end of the gas-phase overflow pipe is threadedly connected to the central hole at the top of the bridge channel.

[0008] In the above solution, the three-phase mixed liquid inlet hole communicates with the inner cavity of the bridge channel, and both the bottom central hole and the top central hole of the bridge channel communicate with the inner cavity of the bridge channel. Beneficial effects

[0009] 1. The present invention innovatively designs a spiral flow channel with a screen. In the gas-liquid separation chamber, the screen can prevent the oil-water mixed liquid phase medium from entering the gas-phase overflow pipe, while the gas can pass through the screen and enter the gas-phase overflow pipe. The oil-water mixed liquid phase medium flows out through the bottom flow port below and enters the outer chamber, and then is separated by an oil-water separation hydrocyclone, having extremely high gas-liquid separation performance.

[0010] 2. The present invention innovatively uses the method of inverted cone gas injection lift to enhance the cyclone separation effect. The gas phase separated by the gas-liquid separation hydrocyclone can enter the inverted cone pipe of the oil-water separation hydrocyclone through the gas-phase overflow pipe and then discharge from the small hole at the tip of the inverted cone, generating an aggregating effect on the oil nucleus during the oil-water separation process, achieving the effect of strengthening the oil-water separation.

[0011] 3. The present invention innovatively designs a bridge channel, which can not only realize the separation of the medium flow before and after separation, but also cleverly inject the separated gas-phase medium into the internal part of the oil-water two-phase gas lift high-efficiency separation module.

[0012] 4. The structure of the present invention is simple, realizing the efficient separation of oil, gas and water three-phase media in the narrow space underground, and combining the cyclone and gas lift technologies to further improve the oil-water separation performance.

[0013] 5. The present invention has the advantages of simple structure and compact layout. It cleverly promotes the efficient separation of the oil-water two-phase medium through gas lift, reduces the lifting cost of the water-phase medium, alleviates the working pressure and maintenance period of the lifting pump, greatly improves the economic benefit. At the same time, through the design of the bridge channel and the installation of the water outlet pipe, it is convenient to further process the separated water phase. It is a high-efficiency separation device for multi-phase media applicable to underground.

[0014] 6. The present invention can complete the separation of the gas phase and the fine separation of the oil-water two-phase through the bridge channel and two-stage hydrocyclones. At the same time, it uses the inverted cone gas injection gas lift technology to strengthen the oil-water separation effect, realizes the efficient separation of the oil-water two-phase, and enables the separated gas phase and oil droplets to directly enter the oil pipe, and the separated water phase is reinjected underground. The present invention has a simple structure and high separation efficiency, can realize the efficient separation of multi-phase media, and is a device for underground cyclone gas lift oil-gas-water three-phase separation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is the overall appearance view of the present invention.

[0016] Figure 2 It is the exploded view of the present invention.

[0017] Figure 3 It is the overall cross-sectional view of the present invention.

[0018] Figure 4 It is the cross-sectional view of the gas-liquid separation module.

[0019] Figure 5 It is an exploded view of the gas-liquid separation module.

[0020] Figure 6 It is a partial enlarged view of the spiral flow channel with a screen.

[0021] Figure 7 They are the external view and sectional view of the bridge channel.

[0022] Figure 8 It is a sectional view of the high-efficiency oil-water two-phase gas-lift separation module.

[0023] Figure 9 It is an exploded view of the high-efficiency oil-water two-phase gas-lift separation module.

[0024] In the figure, 1 is the gas-liquid separation module, 101 is the bridge channel, 1011 is the three-phase mixed liquid inlet hole, 1012 is the crescent hole, 1013 is the central hole at the top of the bridge channel, 1014 is the central hole at the bottom end of the bridge channel, 102 is the tubing coupling, 103 is the water outlet pipe, 1031 is the top inlet of the water outlet pipe, 1032 is the bottom outlet of the water outlet pipe, 104 is the gas-liquid separation hydrocyclone, 1041 is the underflow port, 105 is the spiral flow channel with a screen, 1051 is the filter screen, 1052 is the gas-phase overflow pipe, 106 is the lower outer sleeve, 1061 is the small hole at the bottom end of the lower outer sleeve, 107 is the lower outer chamber, 2 is the high-efficiency oil-water two-phase gas-lift separation module, 201 is the casing coupling, 2011 is the central hole at the bottom of the casing coupling, 202 is the upper outer sleeve, 203 is the oil-water separation hydrocyclone, 2031 is the inlet of the oil-water separation hydrocyclone, 2032 is the water-phase outlet of the oil-water separation hydrocyclone, 204 is the spiral flow channel with a top cover, 2041 is the oil-phase overflow pipe, 205 is the inverted cone, 2051 is the small hole at the tip of the inverted cone, 206 is the upper outer chamber. Specific implementation mode

[0025] The present invention will be further described below with reference to the accompanying drawings:

[0026] Combined with Figures 1-9 As shown, the overall external view of this gas-lift enhanced oil-gas-water three-phase swirl separation device in the same-well injection-production wellbore is as shown in Figure 1 As shown, the device is vertically placed and operates in a vertical working state during operation. It can separate the gas phase, oil phase and water phase from the multiphase medium mixture liquid and directly discharge the separated gas phase and oil phase into the production tubing, and reinject the separated water phase into the ground. Figure 2 It is an exploded view of a gas-lift enhanced oil-gas-water three-phase swirl separation device in the same-well injection-production wellbore, mainly composed of a gas-liquid separation module 1 and a high-efficiency oil-water two-phase gas-lift separation module 2. An overall sectional view of a gas-lift enhanced oil-gas-water three-phase swirl separation device in the same-well injection-production wellbore is as shown in Figure 3As shown, the oil-gas-water three-phase mixture enters the interior of the device through the three-phase mixture inlet hole 1011, flows through the gas-liquid separation module 1 to separate the gas phase and the liquid phase, and the separated liquid phase enters the lower outer chamber 107 and enters the oil-water two-phase gas lift high-efficiency separation module 2 through the crescent hole 1012, and enters the oil-water separation hydrocyclone 203 from the upper outer chamber 206 for separation. Under the lifting action of the gas discharged from the small hole 2051 at the tip of the inverted cone, the oil-water two-phase gas lift high-efficiency separation is realized. The separated oil phase flows out of the device directly from the casing collar 201, and the separated water phase flows through the 103 water outlet pipe into the 102 tubing collar and then is reinjected underground.

[0027] A screen is added at the inlet of the gas overflow pipe at the bottom of the spiral flow channel of the gas-liquid separation module, which can isolate the oil-water two-phase, enable the gas-phase medium to be separated efficiently first, and the gas phase entering the overflow port enters the oil-water two-phase gas lift high-efficiency separation module through the small hole at the tip of the inverted cone. The oil-water two-phase gas lift high-efficiency separation module mainly realizes the high-efficiency separation of oil and water, and realizes the lifting of the oil-phase medium in the hydrocyclone by injecting gas through the inverted cone, so as to improve the separation performance. The separated oil phase is lifted to the ground, and the separated water phase is reinjected underground through the water outlet pipe. A hydrocyclone separation device capable of realizing the high-efficiency separation of oil-water two-phase by gas lift in the present invention further enhances the oil-water separation effect through the gas lift action.

[0028] Figure 4 It is a cross-sectional view of the gas-liquid separation module. The gas-liquid separation module 1 includes a bridge channel 101, a tubing collar 102, a water outlet pipe 103, a gas-liquid separation hydrocyclone 104, a spiral flow channel with a screen 105, and a lower outer sleeve 106; the lower side wall surface of the bridge channel 101 is connected to the lower outer sleeve 106 by threaded connection, and its upper side wall surface is connected to the upper outer sleeve 202 by threaded connection; the lower end of the lower outer sleeve 106 is connected to the tubing collar 102 by threaded connection; the three-phase mixture inlet hole 1011 is opened on the surface of the bridge channel 101, and the central hole 1014 at its bottom end has a thread for external threaded connection with the top of the gas-liquid separation hydrocyclone 104; the bottom of the gas overflow pipe 1052 of the spiral flow channel with a screen 105 is connected with a filter screen 1051, and its top end is connected to the central hole 1013 at the top of the bridge channel by threaded connection and is short-connected to the central hole at the bottom of the inverted cone 205; the water outlet pipe 103 passes through the crescent hole 1012, and its bottom pipe outlet 1032 is embedded and short-connected to the small hole 1061 at the bottom end of the lower outer sleeve, and its top pipe inlet 1031 is embedded and short-connected to the water outlet 2032 of the oil-water separation hydrocyclone.

[0029] The oil-gas-water three-phase mixed liquid enters the gas-liquid cyclone separator 104 from the three-phase mixed liquid inlet hole 1011, and forms a strong cyclonic flow field after spiral acceleration of the spiral flow channel 105 with a screen. The light gas phase with a smaller density gathers toward the axis, passes through the filter screen 1051 and enters the gas phase overflow pipe 1052 of the spiral flow channel 105 with a screen, and is then discharged into the oil-water two-phase gas lift high-efficiency separation module 2, while most of the oil-water two-phase mixed liquid phase flows out from the bottom flow port 1041 of the gas-liquid cyclone separator 104 into the lower outer chamber 107, and a small part is isolated by the filter screen 1051 and also flows out from the bottom flow port 1041 into the lower outer chamber 107. The separated oil-water two-phase mixed liquid phase enters the oil-water two-phase gas lift high-efficiency separation module 2 through the crescent hole 1012 for oil-water separation, and the separated water phase flows through the water outlet pipe 103 into the oil pipe coupling 102, and is then injected back into the underground. Figure 5 10 is an exploded view of the gas-liquid separation module, which is mainly composed of a bridge channel 101, an oil pipe coupling 102, a water outlet pipe 103, a gas-liquid separation cyclone 104, a spiral flow channel with a screen 105 and a lower outer sleeve 106. A partial enlarged view of the spiral flow channel with a screen 105 is shown in FIG. Figure 6 As shown, the filter screen 1051 is covered with a plurality of small filter holes, which can allow the gas phase to pass through and isolate the oil and water phases. Figure 7 These are appearance and cross-sectional views of the bridge channel. A three-phase mixed liquid inlet hole 1011 is opened on the surface of the bridge channel 101. Crescent holes 1012 running through from top to bottom are distributed at both ends of the bridge channel and are symmetrical about the center. The center hole 1013 at the top of the bridge channel is threadedly connected to the gas phase overflow pipe 1052 of the spiral flow channel 105 with a screen, and the center hole 1014 at the bottom of the bridge channel is connected to the top external thread of the gas-liquid separation cyclone 104.

[0030] Figure 8 It is a cross-sectional view of an oil-water two-phase gas lift efficient separation module, and the oil-water two-phase gas lift efficient separation module 2 comprises a casing coupling 201, an upper outer sleeve 202, an oil-water separation cyclone 203, a spiral flow channel with a top cover 204, and an inverted cone 205; the casing coupling 201 is threadedly connected to the upper end of the top cover of the spiral flow channel with a top cover 204, and the central hole 2011 at the bottom of the casing coupling is short-circuited with the oil phase overflow pipe 2041 of the spiral flow channel with a top cover 204; the lower end of the top cover of the spiral flow channel with a top cover 204 is threadedly connected to the oil-water separation cyclone 203 and the upper outer sleeve 202 respectively; the bottom base of the inverted cone 205 is threadedly connected to the bottom of the oil-water separation cyclone 203; the separated water phase is discharged from the water phase outlet 2032 of the oil-water separation cyclone into the top inlet 1031 of the outlet pipe, and then flows out from the bottom outlet 1032 of the outlet pipe for reinjection.

[0031] The oil-water mixed liquid flowing through the crescent hole 1012 enters the upper outer chamber 206, and then flows into the oil-water separation hydrocyclone 203 from the oil-water separation hydrocyclone liquid inlet 2031. It flows through the spiral flow path 204 with a top cover. Under the action of a strong swirling flow field, the light-phase oil phase gathers towards the axis, and the heavy-phase water phase is thrown towards the side wall and flows out from the water phase outlet 2032 of the oil-water separation hydrocyclone into the water outlet pipe 103. The gas phase separated from the gas-liquid separation module 1 is discharged from the small hole 2051 at the tip of the inverted cone, generating a gas-lift effect on the oil phase gathered towards the axis. Under the action of gas lift, more oil phases are separated and flow out from the oil phase overflow pipe 2041 of the spiral flow path 204 with a top cover together with the gas phase, enter the casing collar 201, and then are discharged from the device. The explosion diagram of the oil-water two-phase gas-lift high-efficiency separation module is as Figure 9 shown. This module is composed of a casing collar 201, an upper outer sleeve 202, an oil-water separation hydrocyclone 203, a spiral flow path 204 with a top cover, and an inverted cone 205.

[0032] The design of the present invention is compact, and the operation is reliable and stable. The oil-gas-water three-phase mixed liquid first passes through the gas-liquid separation module to first separate the gas phase from the oil-water mixed liquid medium. The remaining oil-water mixed liquid medium after separation converges into the outer chamber of the device, and then enters the upper oil-water separation module through the crescent hole of the bridge channel for further separation. At the same time, the gas phase separated by the gas-liquid separation module overflows from the tip of the inverted cone of the oil-water separation module, generating a lifting effect on the oil phase in the separation chamber, strengthening the oil-water separation effect in the next stage. The separated water phase is reinjected into the ground through the water outlet pipe, thereby achieving the effect of gas-lift enhanced oil-water separation and realizing the separation of the three-phase medium. The present invention combines cyclone and gas-lift technologies to achieve the efficient separation of oil, gas, and water. It has high working efficiency and good separation effect, is beneficial to the sustainable development of oil fields, and has high practicality.

Claims

1. An air-lift enhanced oil-gas-water three-phase cyclone separation device in an injection-production wellbore of the same well, characterized in that: This air-lift enhanced oil-gas-water three-phase cyclone separation device in an injection-production wellbore of the same well is formed by connecting an oil-water two-phase air-lift high-efficiency separation module to the upper end of a gas-liquid separation module. The oil-water two-phase air-lift high-efficiency separation module includes an upper outer sleeve, an oil-water separation cyclone and an inverted cone. The gas-liquid separation module includes a bridge channel, a tubing collar, a water outlet pipe, a gas-liquid separation cyclone, a spiral flow channel with a screen and a lower outer sleeve. The bridge channel is a cylinder with an inner cavity, and two crescent holes are symmetrically arranged on the outer side of the inner cavity. Both crescent holes penetrate the bridge channel axially. The lower side wall of the bridge channel is threadedly connected to the lower outer sleeve, and its upper side wall is threadedly connected to the upper outer sleeve. The lower end of the lower outer sleeve is threadedly connected to the tubing collar. A three-phase mixed liquid inlet hole is opened on the outer wall of the bridge channel, and its bottom central hole is threadedly connected to the top of the gas-liquid separation cyclone. The gas overflow pipe is provided with a spiral flow channel with a screen and a filter screen. The filter screen is arranged at the bottom of the gas overflow pipe, and the spiral flow channel with a screen is located above the filter screen. The gas overflow pipe passes through the bridge channel upward, and the top end of the gas overflow pipe is short-connected to the central hole of the inverted cone base. The water outlet pipe passes through the crescent hole, and its bottom pipe outlet is embedded and short-connected to the small hole at the bottom end of the lower outer sleeve, and its top pipe inlet is embedded and short-connected to the water outlet of the oil-water separation cyclone. The oil-water two-phase air-lift high-efficiency separation module further includes a casing collar and a spiral flow channel with a top cover. A sealing plate is provided at the lower end of the casing collar, and the center of the sealing plate has a central hole at the bottom of the casing collar. The spiral flow channel with a top cover is formed by the top cover and the spiral flow channel being spaced outside the oil-phase overflow pipe. The top cover is located above the spiral flow channel. The lower port of the casing collar is threadedly connected to the upper step of the top cover, and the central hole at the bottom of the casing collar is short-connected to the oil-phase overflow pipe. The top cover is a cylinder with steps at both the upper and lower ends, and its outer wall and the steps at both the upper and lower ends have external threads. The outer wall of the top cover is threadedly connected to the upper outer sleeve, and the lower step of the top cover is threadedly connected to the oil-water separation cyclone. The bottom base of the inverted cone is threadedly connected to the bottom of the oil-water separation cyclone. The oil-water separation cyclone is located inside the upper outer sleeve, and the inverted cone is located inside the oil-water separation cyclone. The inverted cone is located directly below the oil-phase overflow pipe, and the inverted cone is spaced from the oil-phase overflow pipe.

2. The air-lift enhanced oil-gas-water three-phase cyclone separation device in an injection-production wellbore of the same well according to claim 1, characterized in that: The upper end of the gas overflow pipe is threadedly connected to the central hole at the top of the bridge channel.

3. The air-lift enhanced oil-gas-water three-phase cyclone separation device in an injection-production wellbore of the same well according to claim 2, characterized in that: The three-phase mixed liquid inlet hole is communicated with the inner cavity of the bridge channel, and both the bottom central hole and the top central hole of the bridge channel are communicated with the inner cavity of the bridge channel.

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