Skid-mounted wellhead oil-gas-water three-phase separation and metering device

Abstract

The skid-mounted wellhead oil-gas-water three-phase separation and metering device disclosed by the present invention comprises a pretreatment system, a main separation system, a metering system and a control system which are connected in sequence. Through two-stage separation, when the gas separation is relatively thorough, the device separates and meters the oil, gas and water in the fluid produced at the single well wellhead, and obtains important parameters such as the single well production, water cut and gas-oil ratio according to the metering results.

Description

Technical Field

[0001] The present invention relates to the technical field of single-well metering in oil fields, and particularly relates to a skid-mounted wellhead oil-gas-water three-phase separation metering device. Background Art

[0002] Single-well metering at the oil field site mainly relies on double-volume in the station to measure the single-well output. With the application of new processes and new technologies, the double-volume separator has gradually withdrawn from the historical stage, and is replaced by the dynamometer card method for metering. Its principle is to automatically generate the theoretical displacement of each well using software and formulas, which is calculated based on the effective stroke of the real-time dynamometer card in the background. The calculation parameters need to be calibrated and modified regularly for the single-well output using a tanker or a single-volume tank. Double-volume metering is relatively accurate but has a large volume. The dynamometer card method for metering has a slightly larger error affected by dissolved gas and wellbore conditions. However, these two metering methods only satisfy the metering of liquid volume.

[0003] Currently, there are few truly commercialized devices for single-well three-phase metering of oil wells in the domestic field. The metering method is mainly gas-liquid two-phase metering, and the separation process is all first-stage separation, resulting in incomplete separation of dissolved gas. The liquid metering methods mainly include volumetric (tipping bucket, metering tank) and mass flow meters. Among them, the mass flow meter has a relatively large calculation error in measuring the water cut due to different liquid water content ratios, and its on-site utilization rate is relatively low. Summary of the Invention

[0004] The object of the present invention is to provide a skid-mounted wellhead oil-gas-water three-phase separation metering device, which through two-stage separation, under the condition of relatively complete gas separation, separates and meters the oil, gas, and water in the fluid produced at the single-well wellhead, and obtains important parameters such as single-well liquid production, gas production, water cut, and gas-oil ratio according to the metering results.

[0005] The technical solution adopted by the present invention is that the skid-mounted wellhead oil-gas-water three-phase separation metering device includes a pretreatment system, a main separation system, a metering system, and a control system connected in sequence.

[0006] The present invention is further characterized in that

[0007] The pretreatment system includes a first pipeline, a heating device, and a degassing device connected in sequence; the degassing device is connected to the main separation system through a second pipeline and a third pipeline; a demulsifier dosing device is also included, and the demulsifier dosing device is connected to the first pipeline.

[0008] The main separation system includes a tank body. Inside the tank body, a first partition board and a second partition board are horizontally arranged from top to bottom. A gas chamber is formed between the first partition board and the top wall of the tank body. A fifth partition board and a sixth partition board are vertically arranged between the first partition board and the second partition board. There are gaps between the tops of the fifth partition board and the sixth partition board and the first partition board. A gas dehydration chamber is formed between the fifth partition board and the side wall of the tank body. A number of horizontally arranged partition boards are arranged in a staggered manner up and down between the fifth partition board and the sixth partition board. One end of each horizontally arranged partition board is welded to the board body of the fifth partition board or the sixth partition board, and there is a gap between the other end of each horizontally arranged partition board and the board body of the fifth partition board or the sixth partition board. A number of through holes are arranged in the part of the first partition board between the fifth partition board and the sixth partition board. A number of through holes are arranged in the part of the second partition board between the fifth partition board and the sixth partition board. A third partition board and a fourth partition board are vertically arranged below the second partition board. A primary separation chamber is formed between the third partition board and the side wall of the tank body. A secondary separation chamber is formed between the third partition board and the fourth partition board. A buffer chamber is formed between the fourth partition board and the side wall of the tank body. There is a gap between the top end of the third partition board and the second partition board. A number of through holes are arranged on the lower board body of the third partition board. A number of through holes are arranged on both the upper board body and the lower board body of the fourth partition board, and the middle board body of the fourth partition board is not perforated. A number of through holes are arranged on the second partition board corresponding to the upper part of the primary separation chamber. The degassing device is connected to the tank body through a second pipeline and a third pipeline, and the tank body is also connected to the metering system.

[0009] A drain pipe is arranged at the bottom of the tank body, and a first valve is arranged on the drain pipe.

[0010] The degassing device includes a first degassing cylinder and a second degassing cylinder which are arranged perpendicular to each other and communicated. The first degassing cylinder is horizontally arranged, and the second degassing cylinder is vertically arranged. A liquid separation pipe is inserted into one end of the first degassing cylinder, and the other end of the first degassing cylinder is inserted into the second degassing cylinder. A number of through holes are arranged on the upward side wall of the part of the barrel wall of the first degassing cylinder inside the second degassing cylinder, and a liquid outlet is arranged on the downward side wall of this part of the barrel wall. One end of the liquid separation pipe is connected to the first pipeline, and the other end of the liquid separation pipe is arranged in the first degassing cylinder. A number of through holes are arranged on the side wall of the part of the liquid separation pipe located inside the first degassing cylinder.

[0011] A first internal partition board, a second internal partition board, a third internal partition board and a fourth internal partition board are sequentially arranged from top to bottom in the second degassing cylinder. The end of the first degassing cylinder is located between the third internal partition board and the fourth internal partition board. Both the third internal partition board and the fourth internal partition board are inclined. One end of both the third internal partition board and the fourth internal partition board is connected to the barrel wall of the second degassing cylinder, and there are gaps between the other ends of both the third internal partition board and the fourth internal partition board and the barrel wall of the second degassing cylinder.

[0012] The first internal partition and the second internal partition are arranged horizontally and staggeredly. One end of the first internal partition is connected to the barrel wall of the second degassing cylinder, and the other end of the first internal partition is not connected to the barrel wall of the second degassing cylinder; one end of the second internal partition is connected to the barrel wall of the second degassing cylinder, and the other end of the second internal partition is not connected to the barrel wall of the second degassing cylinder; the top cover of the second degassing cylinder is communicated with the gas dehydration chamber in the tank through the second pipeline, and the bottom cover of the second degassing cylinder is communicated with the first separation chamber in the tank through the third pipeline.

[0013] The metering system includes an oil pipeline, a fourth pipeline, and a water pipeline. One end of the oil pipeline and the water pipeline is communicated with the buffer chamber in the tank; the oil pipeline is located above the water pipeline; the other end of the oil pipeline and the water pipeline is connected to one end of the fourth pipeline, and the other end of the fourth pipeline is communicated with the gas chamber in the tank;

[0014] An oil transfer pump, a first digital pressure transmitter, and a crude oil flowmeter are further arranged on the oil pipeline; a water transfer pump, a second digital pressure transmitter, and a produced water flowmeter are further arranged on the water pipeline; a gas transfer pump, a third digital pressure transmitter, and a gas flowmeter are further arranged on the fourth pipeline;

[0015] An oil-water interface level gauge and a crude oil level gauge inserted inside the tank are further included;

[0016] The oil transfer pump, the water transfer pump, the gas transfer pump, the oil-water interface level gauge, the crude oil level gauge, the first digital pressure transmitter, the crude oil flowmeter, the second digital pressure transmitter, the produced water flowmeter, the third digital pressure transmitter, and the gas flowmeter are all connected to the control system.

[0017] The control system is a PLC control system.

[0018] The demulsifier dosing device includes a demulsifier storage tank, and the demulsifier storage tank is connected to the first pipeline through the fifth pipeline.

[0019] A second valve is arranged on the fifth pipeline.

[0020] The beneficial effects of the present invention are:

[0021] The skid-mounted wellhead oil-gas-water three-phase separation metering device of the present invention is designed in view of the problems existing in the gas-liquid two-phase metering device, such as incomplete gas-liquid separation, large metering error, and poor practicability, as well as the demand for continuous and accurate metering of key wells and critical wells at the production test site for improving oil recovery in oilfields; the device has the characteristics of strong operability, combination of automation and manual operation, simple operation, good adaptability, good mobility, and accurate data, and is suitable for accurately measuring and comparing the change data of oil, gas, and water at the oilfield production site and can be used for a long time. Description of the Drawings

[0022] Figure 1This is a schematic structural diagram of the skid-mounted wellhead oil-gas-water three-phase separation and metering device of the present invention;

[0023] Figure 2 This is a schematic structural diagram of the gas removal device in the skid-mounted wellhead oil-gas-water three-phase separation and metering device of the present invention.

[0024] In the figure, 1. First pipeline, 2. Gas removal device, 3. Second pipeline, 4. Third pipeline, 5. Liquid heating device, 6. Demulsifier dosing device, 7. Tank body, 8. First partition board, 9. Second partition board, 10. Third partition board, 11. Fourth partition board, 12. Fifth partition board, 13. Sixth partition board, 14. Horizontal partition board, 15. Drain pipe, 16. Oil-water interface level gauge, 17. Crude oil level gauge, 18. Oil pipeline, 19. Fourth pipeline, 20. Water pipeline, 21. Oil transfer pump, 22. First digital pressure transmitter, 23. Crude oil flowmeter, 24. Water transfer pump, 25. Second digital pressure transmitter, 26. Produced water flowmeter, 27. Gas transfer pump, 28. Third digital pressure transmitter, 29. Gas flowmeter, 30. Control system, 31. First valve, 32. Sixth pipeline, 33. Oil gathering pipeline into the production tree, 34. Gas chamber, 35. Gas dehydration chamber, 36. First-stage separation chamber, 37. Second-stage separation chamber, 38. Buffer chamber, 39. Oil production well;

[0025] 2-1. First gas removal cylinder, 2-2. Second gas removal cylinder, 2-3. Liquid distribution pipe, 2-4. Liquid outlet, 2-5. First internal partition board, 2-6. Second internal partition board, 2-7. Third internal partition board, 2-8. Fourth internal partition board;

[0026] 6-1. Demulsifier storage tank, 6-2. Fifth pipeline, 6-3. Second valve. Detailed implementation manners

[0027] The present invention will be described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0028] The present invention provides a skid-mounted wellhead oil-gas-water three-phase separation and metering device, as Figure 1-2 shown, which includes a pretreatment system, a main separation system, a metering system and a control system 30 connected in sequence.

[0029] The pretreatment system includes a first pipeline 1, a heating device 5 and a gas removal device 2 connected in sequence. One end of the first pipeline 1 is connected to the oil production well 39, and the other end of the first pipeline 1 is connected to the heating device 5; the liquid coming from the first pipeline 1 is heated by the heating device 5 and then enters the gas removal device 2, and the gas removal device 2 is connected to the main separation system through the second pipeline 3 and the third pipeline 4; it also includes a demulsifier dosing device 6, and the demulsifier dosing device 6 is connected to the first pipeline 1.

[0030] The main separation system includes a tank body 7, inside which a first partition plate 8 and a second partition plate 9 are horizontally arranged from top to bottom; a gas chamber 34 is formed between the first partition plate 8 and the top wall of the tank body 7, a fifth partition plate 12 and a sixth partition plate 13 are vertically arranged between the first partition plate 8 and the second partition plate 9, and there are gaps between the tops of the fifth partition plate 12 and the sixth partition plate 13 and the first partition plate 8; a gas dehydration chamber 35 is formed between the fifth partition plate 12 and the side wall of the tank body 7, several horizontally arranged partition plates 14 are arranged in a staggered manner up and down between the fifth partition plate 12 and the sixth partition plate 13, one end of each horizontally arranged partition plate 14 is welded to the plate body of the fifth partition plate 12 or the sixth partition plate 13, and there is a gap between the other end of each horizontally arranged partition plate 14 and the plate body of the fifth partition plate 12 or the sixth partition plate 13; several through holes are arranged in a part of the first partition plate 8 between the fifth partition plate 12 and the sixth partition plate 13; several through holes are arranged in a part of the second partition plate 9 between the fifth partition plate 12 and the sixth partition plate 13; a third partition plate 10 and a fourth partition plate 11 are vertically arranged below the second partition plate 9; a primary separation chamber 36 is formed between the third partition plate 10 and the side wall of the tank body 7, a secondary separation chamber 37 is formed between the third partition plate 10 and the fourth partition plate 11, and a buffer chamber 38 is formed between the fourth partition plate 11 and the side wall of the tank body 7; there is a gap between the top end of the third partition plate 10 and the second partition plate 9, and several through holes are arranged on the lower plate body of the third partition plate 10; several through holes are arranged on both the upper plate body and the lower plate body of the fourth partition plate 11, and the middle plate body of the fourth partition plate 11 is not perforated; several through holes are arranged on the second partition plate 9 corresponding to the upper part of the primary separation chamber 36; the degassing device 2 is connected to the tank body 7 through a second pipeline 3 and a third pipeline 4, and the tank body 7 is also connected to a metering system.

[0031] The top wall of the tank body 7 is an arched top, and the overall design of the top wall is a detachable air chamber sealing cover;

[0032] A sewage discharge pipe 15 is arranged at the bottom of the tank body 7, and a first valve 31 is arranged on the sewage discharge pipe 15.

[0033] The degassing device 2 includes a first degassing cylinder 2-1 and a second degassing cylinder 2-2 which are perpendicularly arranged and communicated with each other, the first degassing cylinder 2-1 is horizontally arranged, and the second degassing cylinder 2-2 is vertically arranged; a liquid separation pipe 2-3 is inserted into one end of the first degassing cylinder 2-1, and the other end of the first degassing cylinder 2-1 is inserted into the second degassing cylinder 2-2; several through holes are arranged on the upward side wall of the barrel wall part of the first degassing cylinder 2-1 inside the second degassing cylinder 2-2, and a liquid outlet 2-4 is arranged on the downward side wall of this part of the barrel wall; one end of the liquid separation pipe 2-3 is connected to the first pipeline 1, the other end of the liquid separation pipe 2-3 is arranged in the first degassing cylinder 2-1, and several through holes are arranged on the side wall of the part of the liquid separation pipe 2-3 located inside the first degassing cylinder 2-1;

[0034] Inside the second degassing cylinder 2-2, a first internal partition plate 2-5, a second internal partition plate 2-6, a third internal partition plate 2-7, and a fourth internal partition plate 2-8 are sequentially arranged from top to bottom; the end of the first degassing cylinder 2-1 is located between the third internal partition plate 2-7 and the fourth internal partition plate 2-8; both the third internal partition plate 2-7 and the fourth internal partition plate 2-8 are inclined, one end of both the third internal partition plate 2-7 and the fourth internal partition plate 2-8 is connected to the cylinder wall of the second degassing cylinder 2-2, and there is a gap between the other end of both the third internal partition plate 2-7 and the fourth internal partition plate 2-8 and the cylinder wall of the second degassing cylinder 2-2;

[0035] The first internal partition plate 2-5 and the second internal partition plate 2-6 are horizontally and staggeredly arranged. One end of the first internal partition plate 2-5 is connected to the cylinder wall of the second degassing cylinder 2-2, and the other end of the first internal partition plate 2-5 is not connected to the cylinder wall of the second degassing cylinder 2-2; one end of the second internal partition plate 2-6 is connected to the cylinder wall of the second degassing cylinder 2-2, and the other end of the second internal partition plate 2-6 is not connected to the cylinder wall of the second degassing cylinder 2-2; the top cover of the second degassing cylinder 2-2 is communicated with the gas dehydration chamber 35 in the tank body 7 through the second pipeline 3, and the bottom cover of the second degassing cylinder 2-2 is communicated with the first-stage separation chamber 36 in the tank body 7 through the third pipeline 4.

[0036] The metering system includes an oil pipeline 18, a fourth pipeline 19, and a water pipeline 20. One end of both the oil pipeline 18 and the water pipeline 20 is communicated with the buffer chamber 38 in the tank body 7; the oil pipeline 18 is located above the water pipeline 20; the other end of both the oil pipeline 18 and the water pipeline 20 is connected to one end of the fourth pipeline 19, and the other end of the fourth pipeline 19 is communicated with the gas chamber 34 in the tank body 7;

[0037] An oil pump 21, a first digital pressure transmitter 22, and a crude oil flowmeter 23 are further arranged on the oil pipeline 18; a water pump 24, a second digital pressure transmitter 25, and a produced water flowmeter 26 are further arranged on the water pipeline 20; a gas pump 27, a third digital pressure transmitter 28, and a gas flowmeter 29 are further arranged on the fourth pipeline 19;

[0038] It further includes an oil-water interface level gauge 16 and a crude oil level gauge 17 inserted inside the tank body 7;

[0039] The oil pump 21, the water pump 24, the gas pump 27, the oil-water interface level gauge 16, the crude oil level gauge 17, the first digital pressure transmitter 22, the crude oil flowmeter 23, the second digital pressure transmitter 25, the produced water flowmeter 26, the third digital pressure transmitter 28, and the gas flowmeter 29 are all connected to the control system 30; the fourth pipeline 19 is further connected to the oil gathering pipeline 33 of the production tree.

[0040] The gas dehydration chamber 35 of the tank body 7 receives wellhead casing gas through the sixth pipeline 32.

[0041] The control system 30 is a PLC control system.

[0042] The demulsifier dosing device 6 includes a demulsifier storage tank 6-1, and the demulsifier storage tank 6-1 is connected to the first pipeline 1 through a fifth pipeline 6-2.

[0043] A second valve 6-3 is provided on the fifth pipeline 6-2. The incoming liquid heating device 5 is a heating resistance wire.

[0044] The online metering method of the skid-mounted wellhead oil-gas-water three-phase separation metering device mainly adopts a two-stage separation method for the mixed-phase fluid produced at the wellhead of the oil production well 39. After separation, the oil and water are metered separately, and the casing gas directly enters the gas dehydration chamber 35 of the main separation system and is metered after being mixed with the separated gas in the incoming liquid. The method mainly includes the following steps:

[0045] S1. Oil well shut-in connection process:

[0046] After the oil production well 39 shuts in, first close the production and backpressure gates, and then use the processed short joint or the union connection method to connect the wellhead incoming liquid and the wellhead casing gas to each inlet of the skid-mounted wellhead oil-gas-water three-phase separation metering device;

[0047] S2. First add demulsifier to the wellhead incoming liquid. After the incoming liquid is fused with the demulsifier, it enters the incoming liquid heating device 5 for heating, and then passes through the degassing device 2 for pre-separation. The separated liquid enters the first-stage separation chamber 36 of the main separation system, and the gas enters the gas dehydration chamber 35 of the main separation system;

[0048] S3. After the wellhead produced liquid is pretreated, it is divided into two paths of separated gas and liquid. Among them, the gas enters the gas dehydration chamber 35 at the upper part of the tank body 7, and the liquid enters the first-stage separation chamber 36. The gas separated from the liquid passes through the gap above the third partition 10 and enters the second-stage separation chamber 37, and the liquid enters the second-stage separation chamber 37 through the bottom of the first-stage separation chamber 36; The gas at the top of the second-stage separation chamber 37 enters the gas dehydration chamber 35 through the through hole, and the dehydrated gas enters the gas chamber 34 through the through hole of the first partition 8, and the gas in the gas chamber is discharged through the top outlet; After the liquid in the second-stage separation chamber undergoes sedimentation separation, the produced water flows into the buffer chamber 38 through the through hole at the bottom of the fourth partition 11, and the produced oil flows into the buffer chamber 38 through the through hole above the fourth partition 11. Above the oil-water interface in the buffer chamber 38 is the purified oil, and below is the produced water.

[0049] S4. The water level in the buffer chamber 38 is controlled by the oil-water interface level gauge 16. When the water level reaches a certain height, the oil-water interface level gauge 16 transmits information to the control system 30, and the control system 30 controls the water pump 24 to start pumping water for drainage. When a low-level alarm occurs, the control system 30 controls the water pump 24 to stop working and creates a new water layer in the buffer chamber 38. The oil layer in the buffer chamber 38 is detected by the crude oil level gauge 17, and a high-level alarm is set. The control system 30 controls the oil pump 21 to start pumping oil. When the oil layer drops to a low level, the control system 30 controls the oil pump 21 to stop working and creates a new oil layer in the buffer chamber 38. The buffer chamber 38 works in this cycle.

[0050] S5. At the same time, the casing gas of this wellhead is connected to the gas dehydration chamber 35 of the main separation system.

[0051] S6. The gas discharged from the gas chamber 34 is metered by the gas flowmeter 29 to measure the gas production. The oil and water coming from the buffer chamber enter the oil pump 21 and the water pump 24. Corresponding flowmeters are equipped at the outlets of the oil pump 21 and the water pump 24 to measure the oil and water production. After metering, the liquids are mixed and enter the outlet of the skid-mounted wellhead oil-gas-water three-phase separation metering device.

[0052] S7. The outlet of the skid-mounted wellhead oil-gas-water three-phase separation metering device is connected to the gathering pipeline of the single-well, or connected to the Christmas tree of another oil well in the same well site and then returns to the gathering pipeline network to enter the gathering and transportation process.

[0053] The control system 30 mainly collects various data of the instruments and meters and controls the corresponding equipment. The collected data can be transmitted through the RS485 communication Ethernet and uploaded back to the digital monitoring platform, and monitoring charts and reports are formed.

[0054] Embodiment 1

[0055] The skid-mounted wellhead oil-gas-water three-phase separation metering device includes a pretreatment system, a main separation system, a metering system, and a control system 30 connected in sequence.

[0056] The pretreatment system includes a first pipeline 1, a heating device 5, and a degassing device 2 connected in sequence. One end of the first pipeline 1 is connected to the oil production well, and the other end of the first pipeline 1 is connected to the heating device 5. The liquid coming from the first pipeline 1 is heated by the heating device 5 and then enters the degassing device 2. The degassing device 2 is connected to the main separation system through a second pipeline 3 and a third pipeline 4. It also includes a demulsifier dosing device 6, and the demulsifier dosing device 6 is connected to the first pipeline 1.

[0057] Embodiment 2

[0058] The skid-mounted wellhead oil-gas-water three-phase separation metering device includes a pretreatment system, a main separation system, a metering system, and a control system 30 connected in sequence.

[0059] The pretreatment system includes a first pipeline 1, a heating device 5 and a degassing device 2 connected in sequence. One end of the first pipeline 1 is connected to an oil production well, and the other end of the first pipeline 1 is connected to the heating device 5. The liquid flowing through the first pipeline 1 enters the degassing device 2 after being heated by the heating device 5. The degassing device 2 is connected to the main separation system through a second pipeline 3 and a third pipeline 4. It also includes a demulsifier dosing device 6, and the demulsifier dosing device 6 is connected to the first pipeline 1.

[0060] The main separation system includes a tank body 7. Inside the tank body 7, a first partition plate 8 and a second partition plate 9 are horizontally arranged from top to bottom. A gas chamber 34 is formed between the first partition plate 8 and the top wall of the tank body 7. A fifth partition plate 12 and a sixth partition plate 13 are vertically arranged between the first partition plate 8 and the second partition plate 9. There is a gap between the top ends of the fifth partition plate 12 and the sixth partition plate 13 and the first partition plate 8. A gas dehydration chamber 35 is formed between the fifth partition plate 12 and the side wall of the tank body 7. A number of horizontally arranged partition plates 14 are arranged in a staggered manner up and down between the fifth partition plate 12 and the sixth partition plate 13. One end of each horizontal partition plate 14 is welded to the plate body of the fifth partition plate 12 or the sixth partition plate 13, and there is a gap between the other end of each horizontal partition plate 14 and the plate body of the fifth partition plate 12 or the sixth partition plate 13. A number of through holes are arranged in a part of the first partition plate 8 between the fifth partition plate 12 and the sixth partition plate 13. A number of through holes are arranged in a part of the second partition plate 9 between the fifth partition plate 12 and the sixth partition plate 13. A third partition plate 10 and a fourth partition plate 11 are vertically arranged below the second partition plate 9. A primary separation chamber 36 is formed between the third partition plate 10 and the side wall of the tank body 7. A secondary separation chamber 37 is formed between the third partition plate 10 and the fourth partition plate 11. A buffer chamber 38 is formed between the fourth partition plate 11 and the side wall of the tank body 7. There is a gap between the top end of the third partition plate 10 and the second partition plate 9. A number of through holes are arranged on the lower plate body of the third partition plate 10. A number of through holes are arranged on both the upper plate body and the lower plate body of the fourth partition plate 11, and the middle plate body of the fourth partition plate 11 is not perforated. A number of through holes are arranged at the position of the second partition plate 9 corresponding to the upper part of the primary separation chamber 36. The degassing device 2 is connected to the tank body 7 through a second pipeline 3 and a third pipeline 4, and the tank body 7 is also connected to the metering system.

[0061] A sewage discharge pipe 15 is arranged at the bottom of the tank body 7, and a first valve 31 is arranged on the sewage discharge pipe 15.

[0062] Example 3

[0063] Based on the structure of Embodiment 2, the degassing device 2 includes a first degassing cylinder 2-1 and a second degassing cylinder 2-2 which are vertically arranged and connected to each other. The first degassing cylinder 2-1 is horizontally arranged, and the second degassing cylinder 2-2 is vertically arranged. One end of the first degassing cylinder 2-1 is inserted with a liquid distribution pipe 2-3, and the other end of the first degassing cylinder 2-1 is inserted into the second degassing cylinder 2-2. On the upward sidewall of the barrel wall part of the first degassing cylinder 2-1 inside the second degassing cylinder 2-2, there are a number of through holes, and on the downward sidewall of this part of the barrel wall, there is a liquid outlet 2-4. One end of the liquid distribution pipe 2-3 is connected to the first pipeline 1, and the other end of the liquid distribution pipe 2-3 is arranged in the first degassing cylinder 2-1. On the sidewall of the part of the liquid distribution pipe 2-3 located inside the first degassing cylinder 2-1, there are a number of through holes.

[0064] Inside the second degassing cylinder 2-2, a first internal partition 2-5, a second internal partition 2-6, a third internal partition 2-7 and a fourth internal partition 2-8 are arranged in sequence from top to bottom. The end of the first degassing cylinder 2-1 is located between the third internal partition 2-7 and the fourth internal partition 2-8. Both the third internal partition 2-7 and the fourth internal partition 2-8 are inclined. One end of both the third internal partition 2-7 and the fourth internal partition 2-8 is connected to the barrel wall of the second degassing cylinder 2-2, and there is a gap between the other end of both the third internal partition 2-7 and the fourth internal partition 2-8 and the barrel wall of the second degassing cylinder 2-2.

[0065] The first internal partition 2-5 and the second internal partition 2-6 are horizontally and staggeredly arranged. One end of the first internal partition 2-5 is connected to the barrel wall of the second degassing cylinder 2-2, and the other end of the first internal partition 2-5 is not connected to the barrel wall of the second degassing cylinder 2-2. One end of the second internal partition 2-6 is connected to the barrel wall of the second degassing cylinder 2-2, and the other end of the second internal partition 2-6 is not connected to the barrel wall of the second degassing cylinder 2-2. The top cover of the second degassing cylinder 2-2 is communicated with the gas dehydration chamber 35 inside the tank body 7 through the second pipeline 3, and the bottom cover of the second degassing cylinder 2-2 is communicated with the first-stage separation chamber 36 inside the tank body 7 through the third pipeline 4.

[0066] Embodiment 4

[0067] Based on the structure of Embodiment 2, the metering system includes an oil pipeline 18, a fourth pipeline 19, and a water pipeline 20. One end of both the oil pipeline 18 and the water pipeline 20 is communicated with the buffer chamber 38 inside the tank body 7. The oil pipeline 18 is located above the water pipeline 20. The other end of both the oil pipeline 18 and the water pipeline 20 is connected to one end of the fourth pipeline 19, and the other end of the fourth pipeline 19 is communicated with the gas chamber 34 inside the tank body 7.

[0068] An oil transfer pump 21, a first digital pressure transmitter 22, and a crude oil flowmeter 23 are also provided on the oil pipeline 18; a water transfer pump 24, a second digital pressure transmitter 25, and a produced water flowmeter 26 are also provided on the water pipeline 20; a gas transfer pump 27, a third digital pressure transmitter 28, and a gas flowmeter 29 are also provided on the fourth pipeline 19;

[0069] It also includes an oil-water interface level gauge 16 and a crude oil level gauge 17 inserted inside the tank body 7;

[0070] The oil transfer pump 21, the water transfer pump 24, the gas transfer pump 27, the oil-water interface level gauge 16, the crude oil level gauge 17, the first digital pressure transmitter 22, the crude oil flowmeter 23, the second digital pressure transmitter 25, the produced water flowmeter 26, the third digital pressure transmitter 28, and the gas flowmeter 29 are all connected to the control system 30; the fourth pipeline 19 is also connected to the oil gathering pipeline 33 of the inlet production tree.

[0071] The gas dehydration chamber 35 of the tank body 7 receives wellhead casing gas through the sixth pipeline 32.

[0072] The control system 30 is a PLC control system.

[0073] The demulsifier dosing device 6 includes a demulsifier storage tank 6-1, and the demulsifier storage tank 6-1 is connected to the first pipeline 1 through a fifth pipeline 6-2.

[0074] A second valve 6-3 is provided on the fifth pipeline 6-2. The liquid heating device 5 is a pipeline wound with heating resistance wires.

[0075] This device solves the problem of single well metering on site, obtains accurate oil production, water production, and gas production, calculates the water cut and gas-oil ratio of a single well using calculation formulas, and provides reliable data for oilfield production. Taking the field application of foam-assisted oxygen-reduced air flooding to improve oil recovery as an example, this device not only solves the problem of single well metering, grasps the changes in production and water cut, but also can measure the gas production of oil wells. Based on the measured data, it analyzes the dynamic changes of well groups, understands the reservoir, provides reliable data for plan adjustment and expansion of the test, and also has important guiding significance for the improvement of the surface process of the gas flooding test.

Claims

1. A skid-mounted wellhead oil-gas-water three-phase separation and metering device, characterized in that It includes a pretreatment system, a main separation system, a metering system, and a control system (30) connected in sequence; The pretreatment system includes a first pipeline (1), a heating device (5), and a degassing device (2) connected in sequence; the degassing device (2) is connected to the main separation system through a second pipeline (3) and a third pipeline (4); it also includes a demulsifier dosing device (6), and the demulsifier dosing device (6) is connected to the first pipeline (1); The main separation system includes a tank body (7), and a first partition plate (8) and a second partition plate (9) are horizontally arranged in the tank body (7) from top to bottom; a gas chamber (34) is formed between the first partition plate (8) and the top wall of the tank body (7), a fifth partition plate (12) and a sixth partition plate (13) are vertically arranged between the first partition plate (8) and the second partition plate (9), and there are gaps between the tops of the fifth partition plate (12) and the sixth partition plate (13) and the first partition plate (8); a gas dehydration chamber (35) is formed between the fifth partition plate (12) and the side wall of the tank body (7), several horizontally arranged partition plates (14) are arranged in a staggered manner up and down between the fifth partition plate (12) and the sixth partition plate (13), one end of each horizontal partition plate (14) is welded to the plate body of the fifth partition plate (12) or the sixth partition plate (13), and there is a gap between the other end of each horizontal partition plate (14) and the plate body of the fifth partition plate (12) or the sixth partition plate (13); several through holes are arranged in a part of the first partition plate (8) between the fifth partition plate (12) and the sixth partition plate (13); several through holes are arranged in a part of the second partition plate (9) between the fifth partition plate (12) and the sixth partition plate (13); a third partition plate (10) and a fourth partition plate (11) are vertically arranged below the second partition plate (9); a primary separation chamber (36) is formed between the third partition plate (10) and the side wall of the tank body (7), a secondary separation chamber (37) is formed between the third partition plate (10) and the fourth partition plate (11), and a buffer chamber (38) is formed between the fourth partition plate (11) and the side wall of the tank body (7); there is a gap between the top of the third partition plate (10) and the second partition plate (9), and several through holes are arranged on the lower plate body of the third partition plate (10); several through holes are arranged on both the upper plate body and the lower plate body of the fourth partition plate (11), and the middle plate body of the fourth partition plate (11) is not perforated; several through holes are arranged at the corresponding position of the second partition plate (9) above the primary separation chamber (36); the degassing device (2) is connected to the tank body (7) through the second pipeline (3) and the third pipeline (4), and the tank body (7) is also connected to the metering system.

2. The skid-mounted wellhead oil-gas-water three-phase separation and metering device according to claim 1, characterized in that, A drain pipe (15) is arranged at the bottom of the tank body (7), and a first valve (31) is arranged on the drain pipe (15).

3. The skid-mounted wellhead oil-gas-water three-phase separation and metering device according to claim 1, characterized in that, The degassing device (2) includes a first degassing cylinder (2-1) and a second degassing cylinder (2-2) which are perpendicularly arranged and communicated with each other. The first degassing cylinder (2-1) is horizontally arranged, and the second degassing cylinder (2-2) is vertically arranged. One end of the first degassing cylinder (2-1) is inserted with a liquid distribution pipe (2-3), and the other end of the first degassing cylinder (2-1) is inserted into the second degassing cylinder (2-2). A plurality of through holes are formed in the upward side wall of the barrel wall portion of the first degassing cylinder (2-1) in the second degassing cylinder (2-2), and a liquid outlet (2-4) is formed in the downward side wall of the barrel wall portion of the first degassing cylinder (2-1) in the second degassing cylinder (2-2). One end of the liquid distribution pipe (2-3) is connected to the first pipeline (1), the other end of the liquid distribution pipe (2-3) is arranged in the first degassing cylinder (2-1), and a plurality of through holes are arranged on the side wall of the part of the liquid distribution pipe (2-3) located in the first degassing cylinder (2-1). A first internal partition plate (2-5), a second internal partition plate (2-6), a third internal partition plate (2-7) and a fourth internal partition plate (2-8) are sequentially arranged in the second degassing cylinder (2-2) from top to bottom. The end of the first degassing cylinder (2-1) is located between the third internal partition plate (2-7) and the fourth internal partition plate (2-8). The third internal partition plate (2-7) and the fourth internal partition plate (2-8) are both inclined. One end of the third internal partition plate (2-7) and the fourth internal partition plate (2-8) is connected to the barrel wall of the second degassing cylinder (2-2), and there is a gap between the other end of the third internal partition plate (2-7) and the fourth internal partition plate (2-8) and the barrel wall of the second degassing cylinder (2-2). The first internal partition plate (2-5) and the second internal partition plate (2-6) are horizontally and staggeredly arranged. One end of the first internal partition plate (2-5) is connected to the barrel wall of the second degassing cylinder (2-2), and the other end of the first internal partition plate (2-5) is not connected to the barrel wall of the second degassing cylinder (2-2). One end of the second internal partition plate (2-6) is connected to the barrel wall of the second degassing cylinder (2-2), and the other end of the second internal partition plate (2-6) is not connected to the barrel wall of the second degassing cylinder (2-2). The top cover of the second degassing cylinder (2-2) is communicated with the gas dehydration chamber (35) in the tank body (7) through a second pipeline (3), and the bottom cover of the second degassing cylinder (2-2) is communicated with the primary separation chamber (36) in the tank body (7) through a third pipeline (4).

4. The skid-mounted wellhead oil-gas-water three-phase separation and metering device according to claim 1, characterized in that, The metering system includes an oil pipeline (18), a fourth pipeline (19), and a water pipeline (20). One end of the oil pipeline (18) and the water pipeline (20) is communicated with the buffer chamber (38) in the tank body (7). The oil pipeline (18) is located above the water pipeline (20). The other ends of the oil pipeline (18) and the water pipeline (20) are connected to one end of the fourth pipeline (19), and the other end of the fourth pipeline (19) is communicated with the gas chamber (34) in the tank body (7). An oil delivery pipe (18) is further provided with an oil delivery pump (21), a first digital pressure transmitter (22), and a crude oil flowmeter (23); a water delivery pipe (20) is further provided with a water delivery pump (24), a second digital pressure transmitter (25), and a produced water flowmeter (26); a fourth pipe (19) is further provided with a gas delivery pump (27), a third digital pressure transmitter (28), and a gas flowmeter (29); an oil-water interface level gauge (16) and a crude oil level gauge (17) inserted inside the tank body (7) are further included; The oil delivery pump (21), the water delivery pump (24), the gas delivery pump (27), the oil-water interface level gauge (16), the crude oil level gauge (17), the first digital pressure transmitter (22), the crude oil flowmeter (23), the second digital pressure transmitter (25), the produced water flowmeter (26), the third digital pressure transmitter (28), and the gas flowmeter (29) are all connected to a control system (30).

5. The skid-mounted wellhead oil-gas-water three-phase separation and metering device according to claim 1, characterized in that The control system (30) is a PLC control system.

6. The skid-mounted wellhead oil-gas-water three-phase separation and metering device according to claim 1, characterized in that The demulsifier dosing device (6) includes a demulsifier storage tank (6-1), and the demulsifier storage tank (6-1) is connected to the first pipe (1) through a fifth pipe (6-2).

7. The skid-mounted wellhead oil-gas-water three-phase separation and metering device according to claim 6, characterized in that, A second valve (6-3) is provided on the fifth pipe (6-2).

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