Tubular single well crude oil three-phase continuous metering device

Abstract

The invention discloses a tubular single-well crude oil three-phase continuous metering device, and relates to the technical field of oil well single-well metering, the tubular single-well crude oil three-phase continuous metering device comprises two separation metering units, each separation metering unit comprises at least one separation metering pipe and a vertical pipe, the bottom of each separation metering pipe is communicated with the bottom of the corresponding vertical pipe through a connecting pipeline, and each separation metering pipe is communicated with the corresponding vertical pipe through a connecting pipeline. A U-shaped hydraulic weighing structure is formed, and the side wall of the top and the side wall of the bottom of the separation metering pipe are communicated with a liquid inlet pipeline and a liquid outlet pipeline respectively; the gas collecting and metering unit is communicated with an exhaust port of each separating and metering pipe, the fluid switching unit comprises a flow dividing valve communicated with the liquid inlet pipeline and a flow collecting valve communicated with the liquid discharging pipeline, and the water content detection unit is communicated with the liquid discharging pipeline and used for receiving liquid in the separating and metering pipes and measuring the water content of the liquid; and the metering measurement and control unit is electrically connected with the gas collection metering unit, the fluid switching unit and the water content detection unit respectively, and is used for controlling the two separation metering units to operate alternately and realizing continuous measurement.

Description

Technical Field

[0001] This invention relates to the field of single-well metering technology for oil wells, and more specifically to a tubular single-well crude oil three-phase continuous metering device. Background Technology

[0002] Crude oil single-well metering is a key link in oilfield production management, which is of great significance for understanding changes in oil well production capacity, optimizing production parameters and cost accounting. However, since oil wells often produce a three-phase mixture of oil, gas and water, and the flow pattern is complex and the proportions fluctuate greatly, achieving accurate and continuous three-phase metering has always been a technical challenge.

[0003] To achieve accurate three-phase measurement, the initial approach involved converging multiple wells at a metering station and using large-scale equipment for separation and separate measurement. However, large-scale equipment is uneconomical for single-well measurement, and traditional, simple two- or three-phase separation metering devices struggle to achieve complete separation, leading to significant measurement errors. In recent years, with technological advancements, some non-separation metering devices have emerged, such as the X-ray method for online oil, gas, and water testing. While these devices generally meet the requirements for single-well measurement, their high cost makes them unsuitable for widespread use in single-well applications. Another example is the U-tube totalizer continuous oil measurement device disclosed in patent number CN1028525131. However, a closer look at its principle reveals that oil and gas measurements share a single separator and measurement system; oil cannot be measured while gas is being measured, and vice versa. Therefore, it can only be used for production estimation and is not a practical continuous oil measurement device, nor does it have the function of measuring the water content of crude oil.

[0004] In order to improve the existing technology, patent number CN111622738A discloses a tubular oil well gas-liquid automatic metering device and its measurement method, which adopts dual metering units to work in turn to achieve continuous metering. However, it does not explain how the bottom precision weighing sensor 10 weighs the liquid in the tank that is rigidly connected to the external pipeline. It also does not explain or fully disclose how the gas is measured. Similarly, it does not include crude oil water content analysis and metering.

[0005] Therefore, how to provide a single-well metering device that can achieve continuous and automatic metering of oil, gas and water phases and improve metering accuracy is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the present invention provides a tubular single-well crude oil three-phase continuous metering device, which aims to solve the above-mentioned technical problems and provide a single-well metering device with simple structure, low cost, and the ability to realize continuous and automatic metering of oil, gas and water three phases, and improve metering accuracy. In particular, it addresses how to overcome the application difficulties of weighing sensors on rigidly connected containers and how to improve the gas metering and water content measurement functions.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A tubular single-well crude oil three-phase continuous metering device includes:

[0009] Two separate metering units, each of which includes at least one separate metering tube and one riser. The bottom of the separate metering tube and the bottom of the riser are connected by a connecting pipe to form a U-shaped hydraulic weighing structure. The top sidewall and bottom sidewall of the separate metering tube are respectively connected to an inlet pipe and a drain pipe.

[0010] A gas collection and metering unit is connected to the exhaust port of each of the separate metering tubes and is used to collect and measure the gas flow rate.

[0011] A fluid switching unit, comprising a diverter valve connected to the inlet pipe and a merge valve connected to the outlet pipe, for controlling the fluid to alternately enter one of the separation metering units;

[0012] A moisture content detection unit, which is connected to the drain pipe, is used to receive the liquid in the separation metering tube and measure its moisture content;

[0013] The metering and control unit is electrically connected to the gas collection metering unit, the fluid switching unit, and the moisture content detection unit, respectively, and is used to control the two separate metering units to operate alternately and achieve continuous measurement.

[0014] Through the above technical solution, the present invention provides a tubular single-well crude oil three-phase continuous metering device. By setting up two separation metering units and a fluid switching unit, one separation metering unit can simultaneously perform liquid discharge and preparation while the other separation metering unit is inlet, separation, and metering. This achieves seamless connection and continuous measurement of crude oil, gas, and water content, effectively solving the technical problem that existing technologies can only estimate production intermittently. The device uses a U-shaped hydraulic weighing structure to measure liquid mass. This method is based on the principle of hydrostatic pressure and measures the weight of the liquid itself, unaffected by incompletely separated air bubbles mixed in the liquid, thus significantly improving efficiency. The accuracy of liquid volume measurement overcomes the shortcomings of traditional separators, which suffer from incomplete separation and large errors. It integrates the separation, collection, measurement, and detection functions of gas, liquid, and water phases into a single device, which is compact in structure and complete in function. In particular, the independently set water content detection unit solves the technical problem that many previous devices did not have water content measurement function, and can directly output comprehensive data of oil, gas, and water phases. The entire device of this invention is based on a tubular structure rather than a bulky pressure vessel, which greatly reduces the manufacturing, installation, and maintenance costs. At the same time, it avoids the cumbersome procedures such as periodic inspections and daily patrols required for pressure vessels, making it more suitable for single-well field promotion.

[0015] Preferably, in the above-mentioned tubular single-well crude oil three-phase continuous metering device, the connecting pipeline includes a first connecting pipe and a second connecting pipe, and the number of separate metering tubes is multiple, with the bottoms of the multiple separate metering tubes connected to each other through the first connecting pipe; the bottom end of the riser is connected to the first connecting pipe through the second connecting pipe. Connecting the bottoms of multiple separate metering tubes through the first connecting pipe ensures that the liquid level reference of each tube is consistent, forming a unified weighing chamber. The second connecting pipe connects this chamber to the riser, forming a stable and accurate U-shaped hydraulic scale, ensuring the correct implementation of the mass metering principle; the use of a parallel structure of multiple pipes allows for flexible configuration according to the single-well production, increasing the processing capacity while making the liquid flow more stable, which is beneficial for gas-liquid separation and liquid level stability, thereby improving the metering stability of the entire system.

[0016] Preferably, in the above-mentioned tubular single-well three-phase continuous metering device for crude oil, each of the separation metering tubes has an inlet port on its top sidewall, and each inlet port is connected to the inlet pipeline via an inlet branch pipe; each of the separation metering tubes has a drain port at its bottom end, and each drain port is connected to the drain pipeline via a drain branch pipe. By setting independent inlet and drain branch pipes on each separation metering tube, it is ensured that the fluid can be evenly distributed to each parallel pipeline, avoiding short circuits or uneven flow, thereby ensuring the consistency of separation and metering effects.

[0017] Preferably, in the above-mentioned tubular single-well three-phase continuous metering device for crude oil, the end of the inlet branch pipe connected to the separation metering pipe is an upwardly bent elbow structure. A nozzle is installed at the end of the elbow structure. A gas-liquid separator is installed on the inner top of each separation metering pipe. The gas-liquid separator includes a separation umbrella installed below the nozzle and a metal wire mesh installed above the nozzle. The upwardly bent nozzle structure allows the liquid to be sprayed laterally, directly or by rebounding from the pipe wall and falling downwards onto the separation umbrella surface due to gravity, utilizing the difference in gas-liquid viscosity for preliminary gas-liquid separation. Simultaneously, it achieves efficient two-stage separation: the separation umbrella separates the main droplets, while the metal wire mesh above efficiently captures tiny droplets entrained in the gas. This two-stage separation ensures thorough gas-liquid separation, laying the foundation for accurate gas metering and liquid weighing in the subsequent process.

[0018] Preferably, in the above-mentioned tubular single-well three-phase continuous crude oil metering device, the gas collection and metering unit includes a gas manifold and a third connecting pipe. The gas manifold is connected to the top of each of the separate metering pipes via a first gas branch pipe and to the water cut detection unit via a second gas branch pipe. The inlet end of the third connecting pipe is connected to the gas manifold, and the outlet end is connected to the crude oil delivery pipeline. A self-regulating differential pressure control valve and a gas flow meter are installed on the third connecting pipe. The self-regulating differential pressure control valve opens to release gas when the gas pressure in the gas manifold is greater than the set differential pressure at the outlet. The purpose of this structure is to store pressure energy for liquid discharge.

[0019] Preferably, in the above-mentioned tubular single-well crude oil three-phase continuous metering device, the water cut detection unit includes a control valve, a liquid level measuring pipe, and a level gauge. The inlet end of the control valve is connected to the drainage pipeline via a fourth connecting pipe. The bottom end of the liquid level measuring pipe is connected to the outlet end of the control valve, and the top end is connected to the gas manifold via a second gas branch pipe. The level gauge is installed at the top of the liquid level measuring pipe and is used to measure the total liquid level height and the oil-water interface height. This unit is an independent static settling container. The control valve controls the entry and exit of the sample liquid; during the settling period, the oil and water are completely separated under gravity. The level gauge is a guided wave radar level gauge, which can accurately measure the interface height between the oil layer and the water layer, thereby calculating the water cut. This method avoids the disadvantages of online measurement being easily affected by factors such as flow regime and emulsification, and the measurement results are closer to the true value. The entire sampling, settling, measurement, and drainage process can be automatically controlled by the metering and control unit without manual intervention, realizing the automation of water cut measurement.

[0020] Preferably, in the above-mentioned tubular single-well crude oil three-phase continuous metering device, the top end of the riser is connected to the gas manifold via a fifth connecting pipe. Connecting the top end of the riser to the gas manifold ensures that the gas pressure above the level of the isolation fluid in the riser and the top of the separation metering pipe are always consistent; this is a key prerequisite for the U-shaped hydraulic weighing principle to be valid, ensuring the liquid level difference and eliminating measurement errors caused by pressure fluctuations.

[0021] Preferably, in the aforementioned tubular single-well three-phase continuous metering device for crude oil, the riser is filled with an isolation fluid with a density greater than that of crude oil. This isolation fluid (such as saturated brine) forms a clear interface in the riser, converting the gravity of the crude oil into its own level change, while simultaneously preventing viscous crude oil from entering the riser. This ensures that the magnetostrictive level sensor can operate reliably in a clean and stable environment, achieving accurate force-level signal conversion.

[0022] Preferably, in the above-mentioned tubular single-well three-phase continuous crude oil metering device, a level sensor is installed at the top of the riser to detect changes in the level of the isolation fluid inside the riser. The level sensor is a magnetostrictive level sensor, which has high accuracy and reliability, and can sensitively detect minute changes in the level of the isolation fluid inside the riser. This allows for the accurate deduction of the real-time weight of the crude oil in the separation metering tube, ultimately ensuring the high accuracy of the entire liquid metering system.

[0023] Preferably, in the above-mentioned tubular single-well crude oil three-phase continuous metering device, the metering and control unit is electrically connected to the level gauge, the control valve, and the level sensor. It controls the liquid inlet, settling separation, and draining processes of the water cut detection unit, calculates the water cut based on the measured liquid level height, and calculates the liquid weight based on the liquid level change detected by the level sensor. The metering and control unit automatically controls the workflow of the water cut detection unit, processes the data from the level gauge, automatically calculates the water cut, and further calculates the production of pure oil and water by combining this with the total liquid weight. This achieves full automation of data acquisition, processing, and output, improving the intelligence level of the device.

[0024] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a tubular single-well crude oil three-phase continuous metering device, which has the following beneficial effects:

[0025] 1. This invention adopts a collaborative working mode of dual separation metering units and intelligent switching valve group, so that when one separation metering unit is performing metering operations, the other separation metering unit can simultaneously complete venting and preparation, thereby realizing seamless connection and continuous online metering of oil, gas and water three-phase data, overcoming the drawback of traditional devices that can only operate intermittently.

[0026] 2. The liquid metering of this invention adopts a hydraulic weighing system based on the principle of a U-tube communicating vessel. By measuring the liquid level change of the isolation liquid, the weight of crude oil is inferred, eliminating the measurement error caused by incomplete gas separation and mixing into the liquid, thus improving the accuracy of liquid measurement. At the same time, the gas phase is metered through an independent collection and pressure stabilization unit, ensuring stable airflow and improving the accuracy of gas meter measurement. The water content is accurately measured offline through an independent static settling tank, resulting in more reliable results.

[0027] 3. The entire system of this invention is based on pipeline components rather than traditional pressure vessels. This not only significantly reduces manufacturing, installation and maintenance costs, but also avoids the periodic mandatory inspections and heavy daily patrols required by pressure vessels. It simplifies the operation process, reduces safety risks, and makes it very suitable for large-scale deployment and application in single wells in oil fields.

[0028] 4. The device of this invention highly integrates functions such as separation, weighing, gas metering, water cut analysis, and process control into one unit, and achieves intelligent control through a metering and control unit. The system can automatically complete all metering processes, data acquisition, and calculation, and ultimately directly output key data such as the daily production of oil, gas, and water phases, greatly reducing manual intervention, improving data management efficiency, and providing strong technical support for the digital and refined management of oilfields. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0030] Figure 1 The attached figure is a front view of the tubular single-well crude oil three-phase continuous metering device provided by the present invention.

[0031] Figure 2 The attached figure is a left view of the tubular single-well crude oil three-phase continuous metering device provided by the present invention.

[0032] Figure 3 The attached figure is a top view of the tubular single-well crude oil three-phase continuous metering device provided by the present invention.

[0033] in:

[0034] 1-Separation metering unit; 11-Separation metering tube; 12-Riser; 13-Connecting pipe; 131-First connecting pipe; 132-Second connecting pipe; 14-Inlet pipe; 15-Drain pipe; 16-Inlet branch pipe; 161-Nozzle; 17-Drain branch pipe; 18-Fifth connecting pipe; 19-Level sensor; 2-Gas collection metering unit; 21-Gas manifold; 22-Third connecting pipe; 23-First gas branch pipe; 24-Second gas branch pipe; 25-Self-operated differential pressure control valve; 26-Gas flow meter; 3-Fluid switching unit; 31-Diverter valve; 32-Merging valve; 4-Moisture content detection unit; 41-Control valve; 42-Liquid level measuring tube; 43-Level gauge; 44-Fourth connecting pipe; 5-Gas-liquid separator; 51-Separation umbrella; 52-Metal wire mesh. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] See appendix Figure 1 To be continued Figure 3 This invention discloses a tubular single-well crude oil three-phase continuous metering device, comprising:

[0037] Two separate metering units 1, each of which includes at least one separate metering tube 11 and one riser 12. The bottom of the separate metering tube 11 and the bottom of the riser 12 are connected by a connecting pipe 13 to form a U-shaped hydraulic weighing structure. The top sidewall and bottom sidewall of the separate metering tube 11 are respectively connected to an inlet pipe 14 and a drain pipe 15.

[0038] Gas collection and metering unit 2 is connected to the exhaust port of each separation metering tube 11 and is used to collect and measure gas flow rate.

[0039] The fluid switching unit 3 includes a diversion valve 31 connected to the inlet pipe 14 and a confluence valve 32 connected to the outlet pipe 15, for controlling the fluid to alternately enter one of the separation metering units 1;

[0040] Moisture content detection unit 4 is connected to the drain pipe 15 and is used to receive the liquid in the separation metering tube 11 and measure its moisture content.

[0041] The metering and control unit is electrically connected to the gas collection metering unit 2, the fluid switching unit 3, and the moisture content detection unit 4, respectively, and is used to control the two separate metering units 1 to operate alternately and realize continuous measurement.

[0042] In some examples, the connecting pipe 13 includes a first connecting pipe 131 and a second connecting pipe 132, and there are multiple separate metering pipes 11. The bottoms of the multiple separate metering pipes 11 are connected to each other through the first connecting pipe 131; the bottom end of the riser 12 is connected to the first connecting pipe 131 through the second connecting pipe 132.

[0043] More specifically, in this embodiment, each separate metering unit 1 includes four separate metering tubes 11, which are arranged in a rectangular shape. Of course, the number and layout of the separate metering tubes 11 can be determined according to actual needs.

[0044] In some other embodiments, each separation metering tube 11 has a liquid inlet on its top sidewall, and the liquid inlet is connected to the liquid inlet pipeline 14 through a liquid inlet branch pipe 16; each separation metering tube 11 has a liquid outlet at its bottom end, and the liquid outlet is connected to the liquid outlet pipeline 15 through a liquid outlet branch pipe 17.

[0045] In a specific embodiment, the end of the liquid inlet branch pipe 16 connected to the separation metering pipe 11 is an upwardly bent elbow structure. A nozzle 161 is installed at the end of the elbow structure. A gas-liquid separator 5 is installed on the top inner side of each separation metering pipe 11. The gas-liquid separator 5 includes a separation umbrella 51 installed below the nozzle 161 and a metal wire mesh 52 installed above the nozzle 161.

[0046] In a specific example, the gas collection and metering unit 2 includes a gas manifold 21 and a third connecting pipe 22. The gas manifold 21 is connected to the top of each separate metering pipe 11 through a first gas branch pipe 23 and to the moisture content detection unit 4 through a second gas branch pipe 24. The inlet end of the third connecting pipe 22 is connected to the gas manifold 21, and the outlet end is connected to the crude oil transportation pipeline. A self-regulating differential pressure control valve 25 and a gas flow meter 26 are installed on the third connecting pipe 22.

[0047] In some examples, the water content detection unit 4 includes a control valve 41, a liquid level measuring tube 42, and a level gauge 43; the inlet end of the control valve 41 is connected to the drain pipe 15 through the fourth connecting pipe 44, the bottom end of the liquid level measuring tube 42 is connected to the outlet end of the control valve 41, and the top end is connected to the gas manifold 21 through the second gas branch pipe 24. The level gauge 43 is installed at the top of the liquid level measuring tube 42 and is used to measure the total liquid level height and the oil-water interface height.

[0048] Specifically, the liquid level measuring tube 42 is a steel pipe with a uniform inner diameter and smooth surface. The bottom surface is a flat plate with a liquid inlet hole. The upper part of the tube is provided with an air hole connected to the second gas branch pipe 24. The top is equipped with a liquid level gauge 43 through a flange. The liquid level gauge 43 is a guided wave radar liquid level gauge.

[0049] In some specific examples, the top of riser 12 is connected to gas manifold 21 via fifth connecting pipe 18.

[0050] In some other embodiments, riser 12 is filled with a separation fluid with a density greater than that of crude oil.

[0051] In a specific embodiment, a liquid level sensor 19 is installed at the top of the riser 12 to detect changes in the liquid level of the isolation liquid inside the riser.

[0052] More specifically, the metering and control unit is electrically connected to the level gauge 43, control valve 41, and level sensor 19 to control the liquid inlet, settling separation, and discharge processes of the water content detection unit 4. It calculates the water content based on the measured liquid level height and calculates the liquid weight based on the liquid level change detected by the level sensor 19. The specific calculation method and process are existing technologies, or can be simply developed by engineers based on existing technologies, and will not be elaborated further. The metering and control unit is preferably, but not limited to, developed using a PLC. It is electrically connected to the electric actuators of the level sensor 19, level gauge 43, diverter valve 31 (diverter three-way valve), merging valve 32 (merging three-way valve), and control valve 41. It can switch and control the separation and metering processes of the two separation metering units 1, read the brine level and meter the liquid discharge, and control the water content testing process. It reads the liquid level height and water level height, and then calculates the water content based on the water and liquid level height, thereby further calculating the daily production of crude oil and water.

[0053] The core working principle of the tubular single-well crude oil three-phase continuous metering device disclosed in this invention is to achieve continuous metering through the alternating operation of two units, and to achieve high-precision measurement of liquid volume and accurate analysis of water content by using U-shaped pipe hydraulic weighing and offline static settling methods respectively.

[0054] The overall workflow of the device is as follows:

[0055] 1. Fluid switching and unit selection

[0056] The metering and control unit controls the diversion valve 31 and the merging valve 32 in the fluid switching unit 3 to guide the three-phase mixture of oil, gas, and water produced from a single well to one of the separate metering units 1 (e.g., unit A), while the other separate metering unit (unit B) is in a state of metering first, then emptying, or preparing for the next metering. Subsequently, the metering and control unit will switch the diversion valve 31 and the merging valve 32 according to preset times or conditions, causing the fluid to flow into unit B, while unit A begins the metering and drainage process. This cycle repeats, achieving uninterrupted continuous metering.

[0057] 2. Gas-liquid separation and liquid metering (taking Unit A as an example)

[0058] The mixed fluid enters the inlet pipe 14 through the diversion valve 31 and is transported to the inside of the separation metering pipe 11 through the inlet branch pipe 16. The fluid is sprayed upward from the nozzle 161 and first impacts the separation umbrella 51 for preliminary separation. Subsequently, the gas carries tiny droplets upward and, when passing through the metal wire mesh 52, the tiny droplets are captured, aggregated and fall, thereby achieving complete gas-liquid separation.

[0059] After separation, the crude oil liquid accumulates in the separation metering tube 11. Since its bottom is connected to the riser 12 through the first connecting tube 131 and the second connecting tube 132 and filled with isolation fluid, a U-shaped communicating vessel is formed. The increase in the weight of the liquid is converted into pressure on the isolation fluid, forcing the liquid level of the isolation fluid in the riser 12 to rise. The liquid level change of the isolation fluid is accurately detected by the liquid level sensor 19 at the top of the riser 12. When the liquid level reaches the preset height, the liquid feeding is stopped. After the liquid level stabilizes, the liquid level height h is measured, and the draining is started. After the drained liquid reaches the preset liquid level, the draining is stopped, and the liquid level height l is measured. The real-time weight of the accumulated liquid can be calculated based on the height difference and density. This method is based on the hydraulic principle and is not affected by residual air bubbles in the liquid, resulting in high measurement accuracy.

[0060] 3. Gas collection and metering

[0061] The separated gas rises to the top of the separation metering pipe 11 and enters the gas manifold 21 through the first gas branch pipe 23. When the gas pressure in the manifold exceeds the preset value of the self-regulating differential pressure control valve 25, the self-regulating differential pressure control valve 25 opens, and then enters the gas flow meter 26 for precise measurement; the measured gas is finally delivered to the crude oil outlet pipeline.

[0062] 4. Moisture content measurement

[0063] When the separation and metering unit containing the moisture content detection unit prepares to discharge liquid, the control unit opens the control valve 41 of the moisture content detection unit 4. The liquid sample measured in the separation and metering tube 11, driven by pressure, enters the liquid level measuring tube 42 through the discharge pipe 15 and the fourth connecting pipe 44. After the liquid level reaches the preset height, the control valve 41 closes while the confluence valve begins to discharge liquid, allowing the liquid sample to stand and separate in the liquid level measuring tube 42. Due to the different densities of oil and water, a clear oil-water interface will form. During this period, the level gauge 43 at the top of the liquid level measuring tube 42, such as a guided wave radar level gauge, will accurately measure the height of the oil-water interface and the total height of the oil-water mixture. The control unit calculates the moisture content based on these two height values, and then, combined with the total weight of this batch of liquid, calculates the yield of pure oil and water. After the measurement is completed, the control valve 41 reopens, discharging the sample into the output pipe.

[0064] 5. Pressure balancing system

[0065] Riser pressure balance: The top of riser 12 is connected to gas manifold 21 via fifth connecting pipe 18. This ensures that the pressure above the liquid surface on both sides of the U-tube hydraulic weighing system (the side of separate metering pipe 11 and the side of riser 12) is always absolutely balanced, making the reading of liquid level sensor 19 stable and ensuring the accuracy of the weighing core.

[0066] In summary, this invention, through ingenious dual-unit switching, U-tube hydraulic weighing, efficient gas-liquid separation, gas pressure stabilization and metering, and offline static water content measurement, has successfully realized a simple, low-cost, accurate, and truly continuous single-well crude oil three-phase automatic metering device.

[0067] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0068] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A tubular single-well crude oil three-phase continuous metering device, characterized in that, include: Two separate metering units (1), each of the separate metering units (1) includes at least one separate metering tube (11) and one riser (12). The bottom of the separate metering tube (11) and the bottom of the riser (12) are connected by a connecting pipe (13) to form a U-shaped hydraulic weighing structure. The top sidewall and bottom sidewall of the separate metering tube (11) are respectively connected to an inlet pipe (14) and a drain pipe (15). A gas collection and metering unit (2) is connected to the exhaust port of each of the separation metering tubes (11) for collecting and metering gas flow rate. The fluid switching unit (3) includes a diversion valve (31) connected to the inlet pipe (14) and a merging valve (32) connected to the outlet pipe (15), for controlling the fluid to alternately enter one of the separation metering units (1); Moisture content detection unit (4), which is connected to the drain pipe (15), is used to receive the liquid in the separation metering tube (11) and measure its moisture content; The metering and control unit is electrically connected to the gas collection metering unit (2), the fluid switching unit (3) and the moisture content detection unit (4) respectively, and is used to control the two separate metering units (1) to operate alternately and realize continuous measurement.

2. The tubular single-well crude oil three-phase continuous metering device according to claim 1, characterized in that, The connecting pipe (13) includes a first connecting pipe (131) and a second connecting pipe (132). There are multiple separate metering pipes (11), and the bottoms of the multiple separate metering pipes (11) are connected to each other through the first connecting pipe (131). The bottom end of the riser (12) is connected to the first connecting pipe (131) through the second connecting pipe (132).

3. The tubular single-well crude oil three-phase continuous metering device according to claim 1, characterized in that, Each of the separation metering tubes (11) has a liquid inlet on its top sidewall, and the liquid inlet is connected to the liquid inlet pipeline (14) through a liquid inlet branch pipe (16); each of the separation metering tubes (11) has a liquid outlet at its bottom end, and the liquid outlet is connected to the liquid outlet pipeline (15) through a liquid outlet branch pipe (17).

4. The tubular single-well crude oil three-phase continuous metering device according to claim 3, characterized in that, The end of the inlet branch pipe (16) connected to the separation metering pipe (11) is an upwardly bent elbow structure. A nozzle (161) is installed at the end of the elbow structure. A gas-liquid separator (5) is installed on the top inner side of each separation metering pipe (11). The gas-liquid separator (5) includes a separation umbrella (51) installed below the nozzle (161) and a metal wire mesh (52) installed above the nozzle (161).

5. A tubular single-well crude oil three-phase continuous metering device according to claim 1, characterized in that, The gas collection and metering unit (2) includes a gas manifold (21) and a third connecting pipe (22). The gas manifold (21) is connected to the top of each of the separate metering pipes (11) through a first gas branch pipe (23) and to the moisture content detection unit (4) through a second gas branch pipe (24). The inlet end of the third connecting pipe (22) is connected to the gas manifold (21), and the outlet end is connected to the crude oil transport pipeline. A self-regulating differential pressure control valve (25) and a gas flow meter (26) are installed on the third connecting pipe (22).

6. A tubular single-well crude oil three-phase continuous metering device according to claim 5, characterized in that, The moisture content detection unit (4) includes a control valve (41), a liquid level measuring tube (42), and a level gauge (43). The inlet end of the control valve (41) is connected to the drain pipe (15) through a fourth connecting pipe (44). The bottom end of the liquid level measuring tube (42) is connected to the outlet end of the control valve (41), and the top end is connected to the gas manifold (21) through a second gas branch pipe (24). The level gauge (43) is installed at the top of the liquid level measuring tube (42) and is used to measure the total liquid level and the oil-water interface height.

7. A tubular single-well crude oil three-phase continuous metering device according to claim 5, characterized in that, The top end of the riser (12) is connected to the gas manifold (21) via the fifth connecting pipe (18).

8. A tubular single-well crude oil three-phase continuous metering device according to claim 5, characterized in that, The riser (12) is filled with a separation fluid with a density greater than that of crude oil.

9. A tubular single-well crude oil three-phase continuous metering device according to claim 8, characterized in that, A liquid level sensor (19) is installed at the top of the riser (12) to detect changes in the liquid level of the isolation liquid inside the riser.

10. A tubular single-well crude oil three-phase continuous metering device according to claim 9, characterized in that, The metering and control unit is electrically connected to the level gauge (43), the control valve (41) and the level sensor (19), and is used to control the liquid inlet, static separation and liquid discharge process of the water content detection unit (4), calculate the water content according to the measured liquid level height, and calculate the liquid weight according to the liquid level change detected by the level sensor (19).

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