Applicable to downhole flow control type oil-gas-water three-phase separation device for injection and production in the same well

Abstract

The present invention relates to a downhole flow-controlled oil-gas-water three-phase separation device suitable for injection and production in the same well, which includes an upper oil pipe, a flow control module, and an oil-gas-water three-phase separation module. The flow control module is arranged in a flow control tube, and the oil-gas-water three-phase separation module is arranged in a separation outer tube. The upper oil pipe, the flow control tube, and the separation outer tube are arranged in a casing from top to bottom. The casing and the flow control tube are provided with a casing liquid inlet hole at the corresponding position. The upper oil pipe is connected to the flow control tube, and the lower end of the flow control tube is threadedly connected to the oil-gas-water three-phase channel. The lower end of the oil-gas-water three-phase channel is threadedly connected to the separation outer tube. The oil-gas-water three-phase separation module includes a gas-liquid separator, an oil-water separator, and a bottom collecting tube; the separated gas and oil are respectively transported to the gas phase annulus pipe and the oil phase lifting pipe through a gas phase collecting ring, an oil-gas two-phase transport pipe, and an oil-gas-water three-phase channel. The present invention can realize the orderly lifting of the gas phase and the oil phase after multi-stage separation to the ground in a narrow wellbore space, and the water phase is reinjected into the formation.

Description

Technical Field

[0001] The invention relates to an oil-gas-water three-phase separation device in the field of petrochemical industry, and in particular to a downhole flow-controlled oil-gas-water three-phase separation device suitable for injection and production in the same well. Background Art

[0002] At present, the water content in the produced fluid of most oil fields in my country exceeds 95%, which leads to a sharp increase in the mining cost of lifting, transportation and subsequent treatment of the produced fluid, and also causes serious environmental pollution problems. The use of the same well injection and production process and the use of a cyclone separator can achieve cyclone separation of the mixed medium underground, and inject the separated water back into the formation to ensure the energy of the bottom layer; the separated oil is lifted to the ground, which reduces the water content in the produced fluid and effectively reduces the invalid water circulation and ground sewage treatment process. Since the produced fluid contains a large amount of associated gas, it will affect the working efficiency of the screw pump and reduce the service life of the screw pump. At the same time, it will cause the instability of the liquid intake, which reduces the separation efficiency of the cyclone separation device. Most of the existing technologies cannot guarantee three-phase separation and achieve the purpose of steady flow at the same time. Therefore, it is very necessary to develop an automatic flow control type oil-gas-water three-phase medium high-efficiency separation device. Chinese invention patent ZL201710944358.3 discloses an underground three-stage cyclone separation device. Although the device designed by this invention patent can achieve multi-stage separation of gas and liquid, it still has many shortcomings. First, it cannot automatically adjust its own structure according to the amount of liquid inlet to achieve the flow control effect. Secondly, the device can only perform multi-stage separation of gas and liquid underground, and cannot achieve the purpose of oil, gas and water three-phase separation. Summary of the invention

[0003] The purpose of the present invention is to provide a downhole flow-controlled oil-gas-water three-phase separation device suitable for injection and production in the same well. This downhole flow-controlled oil-gas-water three-phase separation device suitable for injection and production in the same well is used to solve the problems of unstable liquid intake and low separation efficiency in the downhole oil, gas and water three-phase separation process in the prior art.

[0004] The technical solution adopted by the present invention to solve the technical problem is: this downhole flow control type oil-gas-water three-phase separation device suitable for injection and production in the same well includes an upper oil pipe, a flow control module, and an oil-gas-water three-phase separation module. The flow control module is arranged in a flow control cylinder, and the oil-gas-water three-phase separation module is arranged in a separation outer cylinder. The upper oil pipe, the flow control cylinder, and the separation outer cylinder are arranged in a casing from top to bottom. A casing liquid inlet hole is arranged at a position corresponding to the casing and the flow control cylinder. The upper oil pipe is connected to the flow control cylinder. The lower end of the flow control cylinder is threadedly connected to the oil-gas-water Three-phase channel, the lower end of the oil-gas-water three-phase channel is threadedly connected to the separation outer cylinder, and the oil-gas-water three-phase separation module includes a gas-liquid separator, an oil-water separator, and a bottom collecting cylinder; the gas phase collecting ring is welded and fixed in the upper oil pipe, the upper end of which is welded with a gas phase annular pipe, and the lower end is connected to the oil-gas two-phase transport pipe, and the lower end of the oil-gas two-phase transport pipe is connected to the oil-gas-water three-phase channel, and the separated gas and oil are transported to the gas phase annular pipe and the oil phase lifting pipe respectively through the gas phase collecting ring, the oil-gas two-phase transport pipe, and the oil-gas-water three-phase channel;

[0005] The flow control module includes a flow control cylinder, a liquid inlet plate, a flat-bottom spring, a positioning plate, a transmission shaft, an upper flow control plate, a lower flow control plate and an oil-gas two-phase transport pipe; the upper part of the flow control cylinder is evenly provided with mixed liquid inlet holes, the liquid inlet plate is welded and fixed to the flow control cylinder, both ends of the flat-bottom spring are flat-bottomed, the upper end of the flat-bottom spring is welded and fixed to the surface of the liquid inlet plate, and the lower end of the flat-bottom spring is welded and fixed to the surface of the positioning plate; the transmission shaft is connected between the liquid inlet plate and the upper flow control plate; the upper flow control plate is a uniformly distributed annular blade, with an upper oil control pipe through hole in the center; the lower flow control plate is an annular uniformly distributed blade, with flow control holes evenly distributed on the annular uniformly distributed blade, with a lower oil control pipe through hole in the center, and it is fixed to the flow control cylinder by edge welding.

[0006] In the above scheme, a circular hole is arranged in the center of the lower bottom surface of the gas phase collecting ring, and the circular hole is divided into a semicircular gas hole and a semicircular oil hole by a partition plate. The semicircular gas hole is connected to the L-shaped gas phase collecting cavity, and the other end of the gas phase collecting cavity is located on the upper surface of the gas phase collecting ring. The semicircular oil hole extends upward to the upper surface of the gas phase collecting ring through the oil phase collecting cavity. The oil phase lifting pipe is arranged inside the gas phase annular hollow pipe and communicates with the oil phase collecting cavity; a penetration plate is welded inside the oil-gas two-phase transport pipe along the length direction, and the penetration plate divides the oil-gas two-phase transport pipe into The gas phase cavity and the oil phase cavity are welded and connected with the circular hole of the gas phase collecting ring at the upper end of the oil-gas two-phase transport pipe, and the circular hole of the oil-gas-water three-phase channel with a partition is welded and connected at the lower end of the oil-gas two-phase transport pipe; a mixed liquid channel is arranged at the edge of the oil-gas-water three-phase channel, and a gas phase channel and an oil phase channel are arranged at the center of the upper surface thereof, the gas phase channel is a semicircular hole, and the oil phase channel is connected in sequence by a semicircular hole, a horizontal hole, and a vertical hole to form a bent channel, and the semicircular holes of the gas phase channel and the oil phase channel are aligned to form a circular hole with a partition.

[0007] In the above scheme, six curved plates are welded between the outer ring of the liquid inlet plate and the middle truncated cone with through holes, and two fixing rods are welded; two hollow positioning shafts are welded and fixed on the positioning plate, which are fixed in the flow control cylinder by welding; the transmission shaft is two solid cylinders, the upper end of which is fixed to the liquid inlet plate by a threaded connection, and the lower end is fixed to the upper flow control plate by a welding connection.

[0008] The oil-gas-water three-phase separation module in the above scheme comprises a gas-liquid separation cylinder, an internal connecting channel of the separator, an oil-water separation cylinder, an underflow collection cylinder, an umbrella-shaped gas-liquid secondary separator, a spiral flow channel, an oil-water secondary separator and a separation outer cylinder;

[0009] The gas-liquid separation cylinder includes a gas-liquid separator inlet, a gas-liquid primary separation gas phase outlet pipe, a gas-liquid secondary separator fixing plate, a gas-liquid separation liquid phase total outlet, and an inner cone. The gas-liquid primary separation gas phase outlet pipe is welded in a circular plate through hole connected to the gas-liquid separation cylinder. The gas-liquid secondary separator fixing plate is circumferentially distributed in the gas-liquid separation cylinder, and is connected to the umbrella-shaped gas-liquid secondary separator by bolts. The inner cone is threadedly connected and fixed to the bottom of the gas-liquid separation cylinder.

[0010] The upper end of the separator's internal connecting channel is threadedly connected to the bottom of the gas-liquid separation cylinder, and the lower end is firstly threadedly connected to the spiral flow channel, and the spiral flow channel is placed in the oil-water primary separation chamber, and then threadedly connected to the upper end of the oil-water separation cylinder;

[0011] The oil-water separation cylinder is fixed by welding, the upper end is connected to the internal connection channel of the separator by threads, and the lower end is connected to the underflow collection cylinder;

[0012] The underflow collection cylinder is a column with a built-in hollow annular cavity. There are four underflow collection ports in the annular shape on the top of the cylinder for collecting the water phase of the oil-water secondary separator, and the liquid phase is gathered through the central underflow collection cavity.

[0013] The umbrella-shaped gas-liquid secondary separator is composed of two umbrella-shaped structures connected at the top, which are connected to the gas-liquid secondary separator fixing plate by bolts;

[0014] The spiral flow channel is a five-channel spiral structure, on which there is an oil-water primary separation oil phase outlet pipe, which is connected to the internal connection channel of the separator above through a thread;

[0015] The secondary oil-water separator is located in the lower cavity of the oil-water separator cylinder, and the secondary oil-water separator oil phase pipe is welded and fixed to the secondary oil-water separator oil phase cavity, the secondary oil-water separator inlet pipe and the primary oil-water separator water phase outlet pipe. Beneficial Effects

[0016] 1. The present invention includes multiple channel structures with unique designs. When the device is working, it is placed vertically underground. The uniquely designed channel structure can lift the multi-stage separated gas phase and oil phase to the ground in an orderly manner in the narrow wellbore space, and inject the water phase back into the formation.

[0017] 2. The present invention can automatically adjust to achieve flow control effect. Two flow control plates that can achieve different flow rates are set in the flow control module. Under different working conditions of liquid inflow, the two plates can be used together to keep the amount of mixed liquid entering the separation module stable, avoiding the reduction of subsequent separation efficiency due to fluctuations in liquid inflow.

[0018] 3. The present invention can achieve fine separation of three-phase mixed media of oil, gas and water. After the mixed liquid enters the separation module, it is first subjected to primary gas-liquid separation, and then the gas phase after primary separation is finely separated by a secondary fine separation device; the liquid phase after gas-liquid separation is subjected to primary oil-water separation, and then the bottom flow water phase is subjected to secondary fine separation, and the multi-stage device is used to maximize the efficient separation of the three-phase medium of oil, gas and water.

[0019] 4. The present invention utilizes a series-parallel design to make the overall structure more compact, which is conducive to underground use and satisfies the need for the device to realize multiple functions in a small space.

[0020] 5. The present invention can realize multi-stage efficient separation of oil, gas and water three-phase mixed media under automatic flow control. At the same time, the entire device is connected by multiple uniquely designed channel structures and matched with series-parallel design to make the overall structure more compact, increasing the applicability of the device in the same well injection and production downhole process.

[0021] 6. The present invention uses multiple uniquely designed channels to connect the whole. The mixed liquid can achieve a stable liquid inlet volume through the flow control module, ensuring the high efficiency of the subsequent separation process. It then passes through the gas-liquid primary separation and secondary fine separation, oil-water primary separation and secondary fine separation devices in sequence, and uses multiple compact cyclone separators in series and parallel to achieve the purpose of efficient separation of the oil, gas and water three-phase mixed liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the appearance diagram of the downhole flow-controlled oil-gas-water three-phase separation device suitable for injection and production in the same well.

[0023] Figure 2 This is an exploded diagram of the module of a downhole flow-controlled oil-gas-water three-phase separation device suitable for injection and production in the same well.

[0024] Figure 3 It is an overall cross-sectional view of a downhole flow-controlled oil-gas-water three-phase separation device suitable for injection and production in the same well.

[0025] Figure 4 This is the exploded diagram of the flow control module.

[0026] Figure 5 This is a cross-sectional view of the flow control module.

[0027] Figure 6 This is the appearance of the liquid inlet tray.

[0028] Figure 7 This is the appearance diagram of the positioning board.

[0029] Figure 8 This is the appearance picture of the upper flow control plate.

[0030] Fig. 9 This is the appearance picture of the lower flow control plate.

[0031] Fig.10 This is a schematic diagram of the working principle of the flow control module.

[0032] Fig.11 This is the appearance diagram of the oil-gas-water three-phase channel.

[0033] Fig.12 This is the overall appearance of the oil-gas-water three-phase separation module.

[0034] Fig.13 This is the exploded diagram of the oil-gas-water three-phase separation module.

[0035] Fig.14 This is a cross-sectional view of the oil-gas-water three-phase separation module.

[0036] Fig.15 This is a cross-sectional view of the gas-liquid separation cylinder.

[0037] Fig.16 This is the appearance diagram of the umbrella-shaped gas-liquid secondary separator.

[0038] Fig.17 This is the appearance diagram of the internal connection channel of the separator.

[0039] Fig.18 This is a cross-sectional view of the internal connecting channel of the separator.

[0040] Fig.19 This is a cross-sectional view of the oil-water separation cylinder.

[0041] Fig. 20 This is the appearance diagram of the spiral flow channel.

[0042] Fig.21 Appearance diagram of oil-water secondary separators in series.

[0043] Fig. 22 Cross-section of the underflow collector.

[0044] Fig.23 Cross-sectional view of the oil phase collection ring.

[0045] Fig.24 Appearance of the oil phase collection tube.

[0046] Fig.25 This is a cross-sectional view of the oil-gas-water three-phase channel.

[0047] Fig.26This is a cross-sectional view of the oil-gas two-phase transport pipe.

[0048] Fig. 27 This is a cross-sectional view of the gas phase collection ring.

[0049] In the figure, 1-casing, 101-casing liquid inlet, 2-flow control module, 3-oil-gas-water three-phase separation module, 4-upper oil pipe, 5-flow control cylinder, 501-mixed liquid inlet, 6-liquid inlet plate, 601-fixing rod, 602-curved plate, 7-flat bottom spring, 8-positioning plate, 801-positioning shaft, 9-transmission shaft, 10-upper flow control plate, 1001-upper oil control pipe through hole, 11-lower flow control plate, 1101-flow control hole, 1102-lower oil control pipe through hole, 12-oil-gas two-phase transport pipe, 1201-gas phase cavity, 1202-oil phase cavity, 13-oil-gas-water three-phase channel, 1301-mixed liquid channel, 1302-gas phase channel, 1303-oil phase channel, 14-gas-liquid separation cylinder, 1401-gas-liquid separator inlet, 1402-gas-liquid primary separation gas phase outlet pipe, 1403-gas-liquid secondary separator fixing plate, 1404-gas-liquid separation liquid phase total outlet, 1405-inner cone, 15-inside of separator Connecting channel, 1501-oil-water separator inlet channel, 1502-oil-water primary separation oil phase outlet channel, 16-oil-water separation cylinder, 1601-oil-water primary separation chamber, 1602-oil-water secondary separation oil phase chamber, 1603-oil-water primary separator water phase outlet pipe, 17-underflow collection cylinder, 1701-underflow collection port, 1702-underflow collection chamber, 18-umbrella-shaped gas-liquid secondary separator, 1801-sector hole, 19-spiral flow channel, 1901-oil Water-first separation oil phase outlet pipe, 20-oil-water second-stage separator, 2001-oil-water second-stage separation oil phase pipe, 2002-oil-water second-stage separator inlet pipe, 2003-oil-water second-stage separation water phase pipe, 21-oil phase collecting ring, 2101-oil phase collecting hole, 22-oil phase collecting tube, 23-gas phase collecting ring, 2301-gas phase collecting cavity, 2302-oil phase collecting cavity, 24-gas phase annulus tube, 25-separation outer cylinder, 26-oil phase lifting tube, 27-separator. DETAILED DESCRIPTION

[0050] The present invention will be further described below in conjunction with the accompanying drawings:

[0051] Combination Figure 1-Figure 27As shown, this downhole flow control type oil-gas-water three-phase separation device suitable for injection and production in the same well includes an upper oil pipe 4, a flow control module 2, and an oil-gas-water three-phase separation module 3. The flow control module 2 is arranged in a flow control tube 5, and the oil-gas-water three-phase separation module 3 is arranged in a separation outer tube 25. The upper oil pipe 4, the flow control tube 5, and the separation outer tube 25 are arranged in a casing 1 from top to bottom. The casing 1 and the flow control tube 5 are provided with a casing liquid inlet hole 101 at a position corresponding to the casing 1. The upper oil pipe 4 is connected to the flow control tube 5. The lower end of the flow control tube 5 is threadedly connected to the oil-gas-water three-phase channel 13. The oil-gas-water three-phase separation module 3 is arranged in a separation outer tube 25. The lower end of the channel 13 is threadedly connected to the separation outer cylinder 25, and the oil-gas-water three-phase separation module 3 includes a gas-liquid separator, an oil-water separator, and an underflow collecting cylinder 17; the gas phase collecting ring 23 is welded and fixed in the upper oil pipe 4, and the gas phase annular pipe 24 is welded on its upper end, and the lower end is connected to the oil-gas two-phase transport pipe 12, and the lower end of the oil-gas two-phase transport pipe 12 is connected to the oil-gas-water three-phase channel 13, and the separated gas and oil are respectively transported to the gas phase annular pipe 24 and the oil phase lifting pipe 26 through the gas phase collecting ring 23, the oil-gas two-phase transport pipe 12, and the oil-gas-water three-phase channel 13.

[0052] The outermost layer is the casing 1, the middle layer is the upper oil pipe 4, the flow control tube 5, the oil-gas-water three-phase channel 13 and the separation outer tube 25 which are connected together in sequence by welding, and the internal devices are, from top to bottom, the gas phase annular tube 24, the gas phase collecting ring 23, the flow control module 2, the oil phase collecting pipe 22, the oil phase collecting ring 21, the separator 27 and the oil-gas-water three-phase separation module 3.

[0053] The flow control module includes a flow control tube 5, a liquid inlet plate 6, a flat-bottom spring 7, a positioning plate 8, a transmission shaft 9, an upper flow control plate 10, a lower flow control plate 11 and an oil-gas two-phase transport pipe 12; the flow control tube 5 is located in the middle of the downhole flow control oil-gas-water three-phase separation device suitable for injection and production in the same well, and its upper end is connected to the upper oil pipe 4 by a thread, and its lower end is connected to the upper end of the oil-gas-water three-phase channel 13 by a thread, and four rows of mixed liquid inlet holes 501 are evenly opened on its upper part; six curved plates 602 are welded between the outer ring of the liquid inlet plate 6 and the middle truncated cone with through holes, and two fixing rods 601 are welded, and the liquid inlet plate 6 and the flow control tube 5 are welded and fixed; the two ends of the flat-bottom spring 7 are flat-bottomed, and its upper end is in contact with the surface of the liquid inlet plate 6 and welded and fixed, and its lower end is in contact with the surface of the positioning plate 8 and welded and fixed. Two hollow positioning shafts 801 are welded and fixed on the positioning plate 8, and are fixed in the flow control tube 5 by welding; the transmission shaft 9 is two solid cylinders, the upper end of which is fixed on the liquid inlet plate 6 by threaded connection, and the lower end is fixed on the upper flow control plate 10 by welding connection; the upper flow control plate 10 is a uniformly distributed annular blade, and an upper oil control pipe through hole 1001 is reserved in the center for the oil-gas two-phase transport pipe 12 to pass through. The lower flow control plate 11 is the same as the upper flow control plate 10, which is an annular uniformly distributed blade, but the blade is uniformly distributed with flow control holes 1101, and a lower oil control pipe through hole 1102 is also reserved in the center for the oil-gas two-phase transport pipe 12 to pass through. It is fixed to the flow control tube 5 by edge welding; a through plate is welded inside the oil-gas two-phase transport pipe 12, so that the inside of the pipe is divided into a gas phase cavity 1201 and an oil phase cavity 1202, and it is connected to the gas phase collection ring 23 by welding.

[0054] The oil-gas-water three-phase separation module comprises a gas-liquid separation cylinder 14, a separator internal connecting channel 15, an oil-water separation cylinder 16, an underflow collecting cylinder 17, an umbrella-shaped gas-liquid secondary separator 18, a spiral flow channel 19, an oil-water secondary separator 20 and a separation outer cylinder 25; the main structure of the gas-liquid separation cylinder 14 comprises a gas-liquid separator inlet 1401, a gas-liquid primary separation gas phase outlet pipe 1402, a gas-liquid secondary separator fixing plate 1403, a gas-liquid separation liquid phase total outlet 1404, and an inner cone 1405; the gas-liquid primary separation gas phase outlet pipe 1402 is welded in a circular plate through hole connected to the gas-liquid separation cylinder 14; the gas-liquid secondary separator fixing plate 1403 is circumferentially distributed in the gas-liquid separation cylinder 14, and is connected to the umbrella-shaped gas-liquid secondary separator. 18 are connected together by bolts, and the inner cone 1405 is threadedly fixed to the bottom of the gas-liquid separation cylinder 14; the upper end of the separator internal connection channel 15 is threadedly connected to the bottom of the gas-liquid separation cylinder 14, and the lower end is first threadedly connected to the spiral flow channel 19, and the spiral flow channel 19 is placed in the oil-water primary separation chamber 1601, and then threadedly connected to the upper end of the oil-water separation cylinder 16; the oil-water separation cylinder 16 is fixed by welding, the upper end is connected to the separator internal connection channel 15 by threads, and the lower end is connected to the bottom flow collection cylinder 17; the bottom flow collection cylinder 17 is a column with a built-in hollow annular cavity, and four bottom flow collection ports 1701 are arranged in an annular manner above it for collecting the water phase of the oil-water secondary separator 20, and the liquid phase is converged through the central bottom flow collection chamber 1702. The umbrella-shaped gas-liquid secondary separator 18 is a gas-liquid secondary separator 18 with two umbrella-shaped structures connected at the top, which is connected to the gas-liquid secondary separator fixing plate 1403 by bolts. The spiral flow channel 19 is a five-channel spiral structure, on which there is an oil-water primary separation oil phase outlet pipe 1901, which is connected to the upper separator internal connection channel 15 through a thread. The oil-water secondary separator 20 is located in the lower cavity of the oil-water separation cylinder 16, and the oil-water secondary separation oil phase pipe 2001 and the oil-water secondary separation oil phase cavity 1602, and the oil-water secondary separator inlet pipe 2002 and the oil-water primary separator water phase outlet pipe 1603 are welded and fixed.

[0055] A circle of casing liquid inlet holes 101 are opened on the casing 1 to enable the entry of liquid; the lower end of the upper oil pipe 4 is welded to the flow control tube 5; the upper end of the oil-gas-water three-phase channel 13 is connected to the flow control tube 5 through a thread, and the gas phase channel 1302 is matched with the hole of the gas phase cavity 1201, the upper surface of the oil phase channel 1303 is matched with the hole of the oil phase cavity 1202, and the lower end is connected to the separation outer tube 25 through a thread; the oil phase collecting ring 21 is welded below the inlet 1401 of the gas-liquid separator and is connected to the oil-gas-water three-phase channel 13 through the oil phase collecting tube 22, and the upper and lower ends of the oil phase collecting tube 22 are respectively threadedly connected and fixed to the oil-gas-water three-phase channel 13 and the oil phase collecting ring 21. The gas phase collecting ring 23 is welded and fixed in the upper oil pipe 4, and its upper end contacts and welds with the lower end surface of the gas phase annular tube 24. The oil phase lifting pipe 26 is coaxially welded on the gas phase collecting ring 23 inside the gas phase annular tube 24, and the lower end oil phase collection cavity 2302 is matched with the oil phase cavity 1202. The upper surface of the separator 27 is parallel to the oil-water secondary separation oil phase cavity 1602 of the oil-water separation cylinder 16, and is welded and fixed on the separation outer cylinder 25.

[0056] A circular hole is centrally arranged on the bottom surface of the gas phase collecting ring 23, and the circular hole is divided into a semicircular gas hole and a semicircular oil hole by a partition. The semicircular gas hole is connected to the L-shaped gas phase collecting chamber 2301, and the other end of the gas phase collecting chamber 2301 is located on the upper surface of the gas phase collecting ring 23. The semicircular oil hole extends upward to the upper surface of the gas phase collecting ring 23 through the oil phase collecting chamber 2302. The oil phase lifting pipe 26 is arranged inside the gas phase annular hollow pipe and communicates with the oil phase collecting chamber 2302. A through plate is welded inside the oil-gas two-phase transport pipe 12 along the length direction, and the through plate divides the oil-gas two-phase transport pipe into the gas phase chamber 1201. The oil-gas two-phase transport pipe is welded to the oil phase cavity 1202, and the upper end of the oil-gas two-phase transport pipe is welded to the circular hole of the gas phase collecting ring, and the lower end of the oil-gas two-phase transport pipe is welded to the circular hole of the oil-gas-water three-phase channel 13 with a partition; a mixed liquid channel 1301 is set at the edge of the oil-gas-water three-phase channel 13, and a gas phase channel 1302 and an oil phase channel 1303 are set at the center of the upper surface thereof, the gas phase channel is a semicircular hole, and the oil phase channel is a bent channel formed by connecting the semicircular hole, the horizontal hole, and the vertical hole in sequence, and the semicircular holes of the gas phase channel 1302 and the oil phase channel 1303 are combined to form a circular hole with a partition.

[0057] The appearance of this downhole flow-controlled oil-gas-water three-phase separation device suitable for injection and production in the same well is shown in the figure below. Figure 1 As shown, the device is in a vertical state when working in the same-well injection and production process, and the mixed liquid enters the internal annulus cavity from the casing liquid inlet hole 101 on the casing 1. Figure 2The exploded diagram of the module of the downhole flow control type oil-gas-water three-phase separation device suitable for injection and production in the same well is mainly composed of a flow control module 2, an oil-gas-water three-phase separation module 3, an upper oil pipe 4, an oil-gas-water three-phase channel 13, an oil phase collection ring 21, an oil phase collection pipe 22, a gas phase collection ring 23, and a gas phase annulus pipe 24. The overall cross-sectional diagram of the downhole flow control type oil-gas-water three-phase separation device suitable for injection and production in the same well is shown in FIG. Figure 3 As shown, the mixed liquid in the internal annular cavity enters the device from 501 and passes through the flow control module 2 and the oil-gas-water three-phase separation module 3 in sequence for separation.

[0058] Figure 4 It is an exploded view of the flow control module, which is mainly composed of a flow control cylinder 5, a liquid inlet plate 6, a flat bottom spring 7, a positioning plate 8, a transmission shaft 9, an upper flow control plate 10, a lower flow control plate 11, and an oil-gas two-phase transport pipe 12. Figure 5 This is a cross-sectional view of the flow control module. The mixed liquid enters the device from the mixed liquid inlet hole 501 on the flow control tube 5, and the mixed liquid flows downward to the liquid inlet plate 6, squeezing the flat bottom spring 7, driving the transmission shaft 9 to make axial movement to control the upper flow control plate 10 below to achieve the flow control effect. Figure 6 This is an appearance diagram of the liquid inlet plate, the main structure of which includes a fixed rod 601 and a curved plate 602. The mixed liquid flows downward to the surface of the curved plate 602, driving the liquid inlet plate 6 to move. Figure 7 This is the appearance diagram of the positioning plate. When the liquid inlet plate 6 squeezes the flat bottom spring 7 to the positioning shaft 801, it stops moving downward. Figure 8 This is the appearance of the upper flow control plate, which has six evenly distributed fan-shaped holes to meet the liquid inlet conditions of low liquid inlet conditions. Fig. 9 This is the appearance diagram of the lower flow control plate. There are six evenly spaced fan-shaped holes on the plate and flow control holes 1101 are distributed on the fan-shaped plate. When the liquid inlet volume is high, the upper flow control plate 10 and the lower flow control plate 11 are used together to achieve flow control. Fig.10 The left figure is a schematic diagram of the working principle of the flow control module. When a small amount of mixed liquid enters the device, the liquid inlet plate 6 squeezes the flat-bottom spring 7 to a small extent, and the upper flow control plate 10 and the lower flow control plate 11 will maintain a certain distance to ensure that sufficient mixed liquid can quickly enter the oil-gas-water three-phase separation module 3; the right figure is a schematic diagram of the working principle of the flow control module when the liquid inlet volume is high. When a large amount of mixed liquid enters the device, the liquid inlet plate 6 squeezes the flat-bottom spring 7 to the positioning axis 801, so that the upper flow control plate 10 and the lower flow control plate 11 The surface overlaps and the flow area is reduced to achieve the flow control effect.

[0059] Fig.11 This is an appearance diagram of the oil-gas-water three-phase channel. After passing through the flow control module 2, the mixed liquid flows from the mixed liquid channel 1301 to the oil-gas-water three-phase separation module 3.

[0060] Fig.12This is the overall appearance diagram of the oil-gas-water three-phase separation module, the exterior of which is mainly composed of a gas-liquid separation cylinder 14, a separator internal connecting channel 15, an oil-water separation cylinder 16 and an underflow collection cylinder 17. Fig.13 It is an exploded view of the oil-gas-water three-phase separation module, and its interior is mainly composed of an umbrella-shaped gas-liquid secondary separator 18, a spiral flow channel 19 and an oil-water secondary separator 20. Fig.14 It is a cross-sectional view of the oil-gas-water three-phase separation module. The mixed liquid enters the gas-liquid separation cylinder 14 from the gas-liquid separator inlet 1401 for primary gas-liquid separation. The gas phase after primary separation moves upward to the umbrella-shaped gas-liquid secondary separator 18 for secondary gas-liquid gravity separation. The gas phase continues to move upward after secondary fine separation; the separated liquid phase flows from the gas-liquid separation liquid phase total outlet 1404 through the separator internal connecting channel 15 to the oil-water separation cylinder for primary oil-water separation. After the liquid phase passes through the spiral flow channel 19, the movement changes from axial to radial, thereby The oil and water are separated in the first stage, and the oil phase after the first stage separation is discharged from the internal connecting channel 15 of the separator and enters the annular cavity between the separation outer cylinder 25 and the oil-gas-water three-phase separation module 3; the water phase after the first stage separation enters the oil-water secondary separator 20 from the water phase outlet pipe 1603 of the oil-water first stage separator for secondary fine separation of oil and water, and the oil phase after the secondary fine separation is discharged from the oil-water secondary separation oil phase pipe 2001 to merge with the oil phase after the first stage separation, and the water phase after the secondary fine separation is collected in the bottom flow collection chamber 1702 and finally injected into the formation. Fig.15 It is a cross-sectional view of the gas-liquid separation cylinder. The mixed liquid enters the gas-liquid separation cylinder 14 from the gas-liquid separator inlet 1401, the liquid phase after the first-stage separation is discharged from the gas-liquid separation liquid phase total outlet 1404, and the gas phase after the first-stage separation is discharged from the gas-liquid first-stage separation gas phase outlet pipe 1402. Fig.16 This is the appearance diagram of the umbrella-shaped gas-liquid secondary separator. The gas phase after the primary separation passes through two vertically stacked umbrella-shaped gas-liquid secondary separators 18, which mainly realize the secondary separation of gas and liquid by gravity sedimentation. The gas phase carrying droplets moves upward and impacts the bottom of the device, then moves upward from the edge. The droplets will adhere to the bottom and settle, enter the middle gap of the upward gas passing device from the edge, and finally rise from the fan-shaped hole 1801 to the next blade. Fig.17 This is an appearance diagram of the internal connection channels of the separator, which mainly include the oil-water separator inlet channel 1501 and the oil-water primary separation oil phase outlet channel 1502. Fig.18 It is a cross-sectional view of the internal connecting channels of the separator. The liquid phase after gas-liquid separation enters the oil-water primary separation chamber 1601 from the oil-water separator inlet channel 1501, and the oil after the primary separation of oil and water is discharged from the oil-water primary separation oil phase outlet channel 1502. Fig.19 It is a cross-sectional view of the oil-water separation cylinder. The primary separation of oil and water is carried out in the primary separation chamber 1601. The water phase after the primary separation enters the secondary oil-water separator 20 from the water phase outlet pipe 1603 of the primary oil-water separator for secondary fine separation. Fig. 20It is an appearance diagram of the spiral flow channel, and the oil-water primary separation oil phase outlet pipe 1901 is connected to the oil-water primary separation oil phase outlet channel 1502 to realize the discharge of the primary separated oil phase. Fig.21 This is an appearance diagram of a series connection of two-stage oil-water separators. The two-stage oil-water separation part is composed of four two-stage oil-water separators 20 connected in series, which can improve the separation efficiency. The top of the two-stage oil-water separator 20 is connected to the two-stage oil-water separation oil phase cavity 1602 to facilitate the collection of the oil phase. Fig. 22 It is a cross-sectional view of the underflow collection tube, in which the underflow collection port 1701 is connected to the oil-water secondary separation water phase pipe 2003 to discharge the water phase after secondary separation into the underflow collection chamber 1702.

[0061] Fig.23 It is a cross-sectional view of the oil phase collection ring. The separated oil phase merges in the annular cavity between the separation outer cylinder 25 and the oil-gas-water three-phase separation module 3 and then moves upward to the oil phase collection hole 2101. Fig.24 2 is an appearance diagram of the oil phase collecting tube, which is a hollow tube. The separated oil phase flows from the oil phase collecting hole 2101 along the oil phase collecting tube 22 to the oil phase channel 1303 . Fig.25 It is a cross-sectional view of the oil-gas-water three-phase channel. The oil phase enters the channel 1303 from the oil phase collection pipe 22 and moves upward. The separated gas phase medium moves upward along the gas phase channel 1302 from the gas-liquid separation cylinder 14. Fig.26 It is a cross-sectional view of the oil-gas two-phase transport pipe. The pipe is divided into two chambers. The separated gas phase moves upward along the gas phase chamber 1201 from the gas phase channel 1302, and the separated oil phase moves upward along the oil phase chamber 1202 from the oil phase channel 1303. Fig. 27 This is a cross-sectional view of the gas phase collecting annulus. The gas phase is discharged from the channel connecting the gas phase collecting chamber 2301 and the gas phase chamber 1201 to the gas phase annulus between the upper oil pipe 4 and the gas phase annulus pipe 24 for collection. The oil phase enters the upper oil phase lifting pipe 26 from the channel connecting the oil phase collecting chamber 2302 and the oil phase chamber 1202 and is lifted to the ground by the screw pump.

[0062] The present invention firstly realizes, through the flow control module, that under different liquid inlet conditions, the mixed liquid flow rate flowing into the separation module is controlled by adjusting its own structure, so as to avoid the reduction of separation efficiency due to unstable flow rate in the subsequent separation process. Then the mixed liquid enters the oil-gas-water three-phase separation module to carry out primary separation and secondary fine separation of the oil, gas and water three-phase mixed medium. Finally, the separated oil phase is lifted to the ground, the separated gas phase is discharged into the gas phase annulus and rises to the ground for collection, and the separated water phase is reinjected into the formation. The whole device is connected by a plurality of channels with different functions, and the series-parallel design is used to make the whole more compact, thereby enhancing the applicability of the device and having high practical value.

Claims

1. A downhole flow control type oil-gas-water three-phase separation device suitable for injection and production in the same well, characterized by: The downhole flow-controlled oil-gas-water three-phase separation device suitable for injection and production in the same well comprises an upper oil pipe, a flow control module, and an oil-gas-water three-phase separation module. The flow control module is arranged in a flow control cylinder, and the oil-gas-water three-phase separation module is arranged in a separation outer cylinder. The upper oil pipe, the flow control cylinder, and the separation outer cylinder are arranged in a casing from top to bottom. A casing liquid inlet hole is arranged at a position corresponding to the casing and the flow control cylinder. The upper oil pipe is connected to the flow control cylinder. The lower end of the flow control cylinder is threadedly connected to the oil-gas-water three-phase channel. The oil-gas-water three-phase The lower end of the channel is threadedly connected to the separation outer cylinder, and the oil-gas-water three-phase separation module includes a gas-liquid separator, an oil-water separator, and a bottom collecting cylinder; the gas phase collecting ring is welded and fixed in the upper oil pipe, the upper end of which is welded with a gas phase annular pipe, and the lower end is connected to the oil-gas two-phase transport pipe, and the lower end of the oil-gas two-phase transport pipe is connected to the oil-gas-water three-phase channel, and the separated gas and oil are transported to the gas phase annular pipe and the oil phase lifting pipe respectively through the gas phase collecting ring, the oil-gas two-phase transport pipe, and the oil-gas-water three-phase channel; The flow control module includes a flow control cylinder, a liquid inlet plate, a flat-bottom spring, a positioning plate, a transmission shaft, an upper flow control plate, a lower flow control plate and an oil-gas two-phase transport pipe; the upper part of the flow control cylinder is evenly provided with mixed liquid inlet holes, the liquid inlet plate is welded and fixed to the flow control cylinder, the two ends of the flat-bottom spring are flat-bottomed, the upper end of the flat-bottom spring is welded and fixed to the surface of the liquid inlet plate, and the lower end of the flat-bottom spring is welded and fixed to the surface of the positioning plate; the transmission shaft is connected between the liquid inlet plate and the upper flow control plate; the upper flow control plate is an evenly distributed annular blade, and a through hole for the upper oil control pipe is reserved in the center; the lower flow control plate is an annular evenly distributed blade, and flow control holes are evenly distributed on the annular evenly distributed blade, and a through hole for the lower oil control pipe is reserved in the center, which is fixed to the flow control cylinder by edge welding; A circular hole is centrally arranged on the bottom surface of the gas phase collecting ring, and the circular hole is divided into a semicircular gas hole and a semicircular oil hole by a partition. The semicircular gas hole is connected to an L-shaped gas phase collecting cavity, and the other end of the gas phase collecting cavity is located on the upper surface of the gas phase collecting ring. The semicircular oil hole extends upward to the upper surface of the gas phase collecting ring through the oil phase collecting cavity. The oil phase lifting pipe is arranged inside the gas phase annular hollow pipe and communicates with the oil phase collecting cavity. A through plate is welded inside the oil-gas two-phase transport pipe along the length direction, and the through plate divides the oil-gas two-phase transport pipe into The gas phase cavity and the oil phase cavity, the upper end of the oil-gas two-phase transport pipe and the circular hole of the gas phase collecting ring are welded and connected, and the lower end of the oil-gas two-phase transport pipe is welded and connected to the circular hole of the oil-gas-water three-phase channel with a partition; a mixed liquid channel is set at the edge of the oil-gas-water three-phase channel, and a gas phase channel and an oil phase channel are set at the center of the upper surface thereof, the gas phase channel is a semicircular hole, and the oil phase channel is connected in sequence by a semicircular hole, a horizontal hole, and a vertical hole to form a bending channel, and the semicircular holes of the gas phase channel and the oil phase channel are aligned to form a circular hole with a partition; The oil-gas-water three-phase separation module comprises a gas-liquid separation cylinder, a separator internal connection channel, an oil-water separation cylinder, an underflow collection cylinder, an umbrella-shaped gas-liquid secondary separator, a spiral flow channel, an oil-water secondary separator and a separation outer cylinder; The gas-liquid separation cylinder includes a gas-liquid separator inlet, a gas-liquid primary separation gas phase outlet pipe, a gas-liquid secondary separator fixing plate, a gas-liquid separation liquid phase total outlet, and an inner cone. The gas-liquid primary separation gas phase outlet pipe is welded in a circular plate through hole connected to the gas-liquid separation cylinder. The gas-liquid secondary separator fixing plate is circumferentially distributed in the gas-liquid separation cylinder. The gas-liquid secondary separator fixing plate is connected to the umbrella-shaped gas-liquid secondary separator by bolts. The inner cone is threadedly connected and fixed to the bottom of the gas-liquid separation cylinder. The upper end of the separator's internal connecting channel is threadedly connected to the bottom of the gas-liquid separation cylinder, and the lower end is firstly threadedly connected to the spiral flow channel, the spiral flow channel is placed in the oil-water primary separation chamber, and then threadedly connected to the upper end of the oil-water separation cylinder; The oil-water separation cylinder is fixed by welding, the upper end is connected to the internal connection channel of the separator by threads, and the lower end is connected to the underflow collection cylinder; The underflow collection cylinder is a column with a built-in hollow annular cavity. There are four underflow collection ports in the annular shape on the top of the cylinder for collecting the water phase of the oil-water secondary separator, and the liquid phase is gathered through the central underflow collection cavity. The umbrella-shaped gas-liquid secondary separator is composed of two umbrella-shaped structures connected at the top, which are connected to the gas-liquid secondary separator fixing plate through bolts.

2. The downhole flow control type oil-gas-water three-phase separation device suitable for injection and production in the same well according to claim 1, characterized in that: Six curved plates are welded between the outer ring of the liquid inlet plate and the middle truncated cone with through holes, and two fixing rods are welded; two hollow positioning shafts are welded and fixed on the positioning plate, and are fixed in the flow control cylinder by welding; the transmission shaft is two solid cylinders, the upper ends of which are fixed to the liquid inlet plate by threaded connection, and the lower ends are fixed to the upper flow control plate by welding connection.

3. The downhole flow control type oil-gas-water three-phase separation device suitable for injection and production in the same well according to claim 2, characterized in that: The spiral flow channel is a five-channel spiral structure, on which is an oil-water primary separation oil phase outlet pipe, which is connected to the internal connecting channel of the separator above through a thread.

4. The downhole flow control type oil-gas-water three-phase separation device suitable for injection and production in the same well according to claim 3, characterized in that: The secondary oil-water separator is located in the lower cavity of the oil-water separation cylinder, and the secondary oil-water separation oil phase pipe and the secondary oil-water separation oil phase cavity, the secondary oil-water separator inlet pipe and the primary oil-water separator water phase outlet pipe are welded and fixed.

Images