Double-chamber alternate differential pressure type crude oil metering device

Abstract

The utility model discloses a double -chamber rotation differential pressure formula crude oil metering device belongs to oilfield oil production equipment technical field, and this device includes the metering tank casing, is equipped with the baffle in the metering tank casing, and the baffle is separated into first chamber and second chamber with the lower part of metering tank casing, and forms the upper part gas phase intercommunication space on the upper part of metering tank casing. Every chamber is connected liquid inlet line and liquid outlet line respectively, and is equipped with differential pressure detection unit, liquid level detection unit and valve. The lower detection port of differential pressure detection unit is higher than the corresponding liquid outlet, and is arranged, so that the water seal reserved section is formed below the lower detection port. Control unit controls two chambers to alternate liquid inlet measurement and liquid discharge, and closes the valve on the corresponding liquid outlet line at the end of liquid discharge to reserve the water seal, avoids the gas to flow through the liquid outlet line. The device is compact in structure, can continuously measure, and is suitable for temporary oil gas water synchronous measurement of test oil well.

Description

Technical Field

[0001] This utility model relates to the field of oilfield production equipment technology, specifically to a dual-chamber alternating differential pressure crude oil metering device. Background Technology

[0002] In oilfield production management, real-time and accurate metering of crude oil, natural gas, and associated water produced by a single oil well is a crucial foundation for optimizing oil production processes, adjusting mixed transportation schemes, and conducting cost assessments and settlements. For newly developed or test-produced oil wells, the deployment of metering equipment on-site typically needs to be completed within a short period, and the metering location needs to be moved or adjusted promptly according to changes in well production. Therefore, the compactness of the equipment structure, ease of installation, and the ability to simultaneously meter multiple phase products are all of paramount importance.

[0003] Existing crude oil metering equipment typically includes glass tube gauging devices, mass flow meters, and tipping bucket meters. Glass tube gauging devices rely heavily on manual readings, have low automation levels, and struggle to obtain continuous metering data. While mass flow meters can achieve high-precision flow measurement, they have stringent requirements for installation conditions, medium conditions, and on-site support, and their equipment and maintenance costs are relatively high. Tipping bucket meters can achieve liquid metering through constant-volume tilting, but when the incoming liquid contains natural gas, associated water, or foam, the tipping bucket's filling state, tilting stability, and effective volume are easily affected by multiphase flow disturbances, leading to increased liquid metering errors.

[0004] Furthermore, some liquid metering devices lack stable gas-liquid separation spaces and gas metering channels, requiring separate gas metering devices for natural gas produced from oil wells, resulting in complex on-site connections. Even with gas metering channels, if the chamber is completely emptied during the liquid drainage stage, natural gas in the gas phase space may leak out through the drainage pipeline, affecting gas metering results and reducing the accuracy of simultaneous metering of oil, gas, and water production. Therefore, for pilot production wells and temporary metering scenarios, a crude oil metering device that can be transported as a whole, installed quickly, and whose gas leakage can be minimized during continuous metering is still needed. Utility Model Content

[0005] This invention provides a dual-chamber alternating differential pressure crude oil metering device, which achieves continuous alternating metering through a single-tank dual-chamber structure and retains a water seal at the end of the drain of each chamber. It can reduce the impact of gas crossflow on gas metering results while being compact and easy to move, thus making it suitable for simultaneous oil, gas and water metering in test wells or temporary metering scenarios.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A dual-chamber alternating differential pressure crude oil metering device includes a metering tank shell with a partition inside. The partition extends upward from the bottom of the metering tank shell, dividing the lower part of the shell into a first chamber and a second chamber. A space is left between the upper end of the partition and the top of the shell, forming an upper gas-phase communication space that connects the first and second chambers. This structure isolates the liquid phase spaces of the two chambers while allowing them to communicate with each other, enabling independent liquid intake and drainage for each chamber, while also allowing any released natural gas to enter the shared gas-phase space.

[0007] The first and second chambers are connected to inlet and outlet pipes, respectively, and each inlet and outlet pipe is equipped with a valve. Each valve can be an electric valve and is controlled by a control unit, so that when one chamber is in the inlet metering state, the other chamber is in the outlet or waiting to be switched.

[0008] The device also includes a differential pressure detection unit and a liquid level detection unit. The differential pressure detection unit includes a first differential pressure detection unit communicating with a first chamber and a second differential pressure detection unit communicating with a second chamber. Each differential pressure detection unit has an upper detection port and a lower detection port spaced apart along the height direction of the corresponding chamber. The lower detection port is positioned higher than the drain outlet of the corresponding chamber, creating a water seal reserved section in the space below the lower detection port and above the drain outlet within the corresponding chamber. The liquid level detection unit includes a first liquid level detection unit located in the first chamber and a second liquid level detection unit located in the second chamber. The liquid level detection unit is used to detect whether the corresponding chamber has reached a preset metered liquid level.

[0009] The control unit is located in a control box outside the metering tank shell and is electrically connected to each valve, differential pressure detection unit, and liquid level detection unit. The control unit is configured to output valve opening and closing control signals based on the detection signals from the liquid level detection unit and the differential pressure detection unit, so that the first chamber and the second chamber alternately connect the inlet and outlet pipes, and close the valve on the corresponding outlet pipe when the liquid level in the corresponding chamber drops to a preset closing level; the preset closing level is not lower than the height of the lower detection port. The control unit controls the opening and closing state of each valve based on the signals from the liquid level detection unit and the differential pressure detection unit, so that the first chamber and the second chamber alternately perform inlet metering and outlet operations. During outlet operation, when the control unit determines that the liquid level has dropped to near the lower detection port or the differential pressure signal has reached a preset closing threshold, it closes the valve on the corresponding outlet pipe, retaining liquid in the water seal section, thereby preventing gas in the upper gas-connected space from flowing through the outlet pipe.

[0010] Furthermore, the upper part of the metering tank shell is provided with a gas outlet that communicates with the upper gas connection space, and a gas flow meter is connected to the gas outlet. A mist eliminator can also be installed inside the metering tank shell, below the gas outlet, to separate liquid droplets carried in the gas and improve the metering stability of the gas flow meter.

[0011] Furthermore, the differential pressure detection unit can employ a differential pressure sensor, with a preset height difference between the upper and lower detection ports. The detection position of the liquid level detection unit is higher than the lower detection port, thus defining a constant-volume metering section within the corresponding chamber between the detection position of the liquid level detection unit and the lower detection port. For the first and second chambers arranged symmetrically from left to right, their effective cross-sectional areas are the same. The first and second liquid level detection units can be located at the same height, and the lower detection ports of the first and second differential pressure detection units can also be located at the same height, thereby ensuring that the single effective metering volume of the two chambers remains consistent.

[0012] Furthermore, the drain lines of the first and second chambers can merge into a main drain line downstream of their respective valves, and the inlet lines of the first and second chambers can connect to the main inlet line upstream of their respective valves. For ease of transport and rapid on-site deployment, the device may also include a steel frame for housing and supporting the metering tank shell. For use in cold regions, the outer walls of the metering tank shell, the inlet lines, and the drain lines can be equipped with electric heating tapes, with an insulation layer covering the outside of the heating tapes.

[0013] Compared with the prior art, the beneficial effects of this utility model are as follows: First, the metering tank shell is divided into two chambers, isolated at the bottom and connected at the top, by a partition. Compared to a design with two independent tanks arranged side by side, the overall structure is more compact, facilitating overall transportation and rapid on-site installation. Second, the two chambers can alternately perform liquid inlet and outlet metering operations, reducing metering gaps during the outlet process in single-chamber metering equipment and improving continuous metering capability. Third, the lower detection port is positioned higher than the outlet, and a water seal is reserved below the lower detection port, ensuring that liquid remains at the outlet end of the chamber, reducing the possibility of gas leakage from the outlet pipeline and improving gas metering stability. Finally, this device can obtain metering data of the liquid and gas produced by the oil well by combining liquid level, differential pressure, and gas flow signals. Its simple structure makes it suitable for pilot production wells, temporary metering points, and oilfield sites requiring frequent relocation. Attached Figure Description

[0014] Figure 1 This utility model presents a structural schematic diagram of a dual-chamber alternating differential pressure crude oil metering device.

[0015] Explanation of reference numerals in the attached figures: 1: Metering tank shell; 2: Baffle plate; 3: Mist eliminator; 4: Crude oil A inlet of metering tank; 5: Crude oil B inlet of metering tank; 6: Upper detection port of differential pressure sensor A; 7: Lower detection port of differential pressure sensor A; 8: Upper detection port of differential pressure sensor B; 9: Lower detection port of differential pressure sensor B; 10: Liquid level sensor A; 11: Liquid level sensor B; 12: Right inlet electric valve; 13: Left inlet electric valve; 14: Left outlet electric valve; 15: Right outlet electric valve; 16: Gas outlet; 17: Gas flow meter; 18: First drain port; 19: Second drain port; 20: Water seal reserved section. Detailed Implementation

[0016] These embodiments are provided to make the present invention thorough and complete, and to fully express the scope of the present invention to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, material composition, numerical expressions, and values ​​set forth in these embodiments should be interpreted as merely exemplary and not as limiting.

[0017] The embodiments of this utility model will be further described in detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this utility model by way of example, but should not be used to limit the scope of this utility model. This utility model can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0018] Example 1: Refer to Figure 1 This embodiment provides a dual-chamber alternating differential pressure crude oil metering device, mainly comprising a metering tank shell 1. A partition 2 is vertically arranged inside the metering tank shell 1, extending upwards from the bottom of the shell and dividing the lower part of the tank into a left chamber and a right chamber. The left chamber can serve as the first chamber, and the right chamber as the second chamber. The upper end of the partition 2 is lower than the top of the metering tank shell 1, allowing the left and right chambers to form an interconnected gas phase space in the upper part of the shell 1.

[0019] The upper part of the left chamber is equipped with a crude oil A inlet 4 for the metering tank, and the upper part of the right chamber is equipped with a crude oil B inlet 5 for the metering tank. A left inlet electric valve 13 is installed on the inlet pipe where the crude oil A inlet 4 is located, and a right inlet electric valve 12 is installed on the inlet pipe where the crude oil B inlet 5 is located. The lower parts of the left and right chambers are respectively equipped with a first drain port 18 and a second drain port 19. A left outlet electric valve 14 is installed on the drain pipe of the left chamber, and a right outlet electric valve 15 is installed on the drain pipe of the right chamber. The two drain pipes can merge into a main drain pipe downstream of the left outlet electric valve 14 and the right outlet electric valve 15.

[0020] A set of differential pressure sensors is installed on the tank wall corresponding to the left chamber, including an upper detection port 6 and a lower detection port 7 of differential pressure sensor A. The lower detection port 7 of differential pressure sensor A is positioned higher than the first drain port 18, thus forming a water seal reserved section 20 in the left chamber from the lower detection port 7 to the first drain port 18. Correspondingly, an upper detection port 8 and a lower detection port 9 of differential pressure sensor B are installed in the right chamber, with the lower detection port 9 of differential pressure sensor B positioned higher than the second drain port 19. Therefore, the space from the lower detection port 9 to the second drain port 19 forms a water seal reserved section 20 in the right chamber. The water seal reserved section 20 is the spatial area defined within the corresponding chamber by the height relationship between the lower detection port and the drain port.

[0021] The left chamber is equipped with a level sensor A10, and the right chamber is equipped with a level sensor B11. Level sensors A10 and B11 are used to detect whether the corresponding chambers have reached the preset metering level. The volume between the preset metering level and the corresponding lower detection port can be used as the single effective metering volume; when the cross-sectional areas of the left and right chambers, the installation height of the level sensors, and the installation height of the lower detection ports are the same, the single effective metering volumes of the two chambers are the same.

[0022] The top of the metering tank shell 1 is provided with a gas outlet 16, which is connected to a gas flow meter 17. Inside the metering tank shell 1, below the gas outlet 16, a mist eliminator 3 is provided. After the gaseous crude oil enters any chamber, the gas rises into the upper gas-connected space, and after passing through the mist eliminator 3 to remove the liquid droplets it carries, it is discharged from the gas outlet 16. The gas flow meter 17 is used to measure the gas flow rate.

[0023] This device also includes a control box, which can be installed on the outside of the metering tank shell 1 or on a steel frame. The control box (not shown in the figure) houses a programmable logic controller (PLC) as the control unit. The control unit is electrically connected to the right inlet electric valve 12, the left inlet electric valve 13, the left outlet electric valve 14, the right outlet electric valve 15, a differential pressure sensor, a liquid level sensor, and a gas flow meter 17.

[0024] The following describes the working process of this device using the example of liquid metering in the left chamber first. The control unit first opens the left inlet electric valve 13, allowing crude oil containing natural gas and water to enter the left chamber from the crude oil A inlet 4 of the metering tank, while simultaneously putting the right chamber into a draining or metering state. After the crude oil enters the metering tank shell 1, due to changes in pressure and flow rate, the carried or precipitated natural gas rises to the upper gas-connected space and enters the gas flow meter 17 through the mist eliminator 3 and gas outlet 16.

[0025] When the liquid level in the left chamber reaches the detection position of the level sensor A10, the control unit determines that the left chamber has completed one liquid inlet metering cycle. Subsequently, the control unit closes the left inlet electric valve 13 and opens the right inlet electric valve 12, allowing the right chamber to begin liquid inlet metering; simultaneously, it opens the left outlet electric valve 14, allowing the left chamber to begin draining. By alternating between the left and right chambers, near-continuous liquid metering can be achieved.

[0026] During the drainage process in the left chamber, the control unit continuously reads the signal from the left differential pressure sensor. When the liquid level drops to near the lower detection port 7 of differential pressure sensor A, the differential pressure signal decreases to the preset closing threshold, and the control unit immediately closes the left outlet electric valve 14. Since the lower detection port 7 of differential pressure sensor A is higher than the first drainage port 18, the water seal reserved section below the lower detection port in the left chamber still retains liquid. This liquid forms a water seal, thereby preventing natural gas in the upper gas-connected space from leaking out through the left drainage pipe. The drainage process in the right chamber is the same as that in the left chamber.

[0027] In one metering method, the control unit can record the number of effective drainages from the left outlet electric valve 14 and the right outlet electric valve 15 per unit time, and obtain the volumetric output of water-containing crude oil per unit time based on the product of the single effective metering volume and the number of effective drainages. The single effective metering volume can be pre-calibrated or calculated based on the cross-sectional area of ​​the corresponding chamber and the height difference between the liquid level sensor detection position and the lower detection port.

[0028] In another metering method, when the liquid in the corresponding chamber covers the upper and lower detection ports of the differential pressure sensor, the control unit can calculate the average liquid density based on the differential pressure value measured by the differential pressure sensor and the preset height difference between the upper and lower detection ports. If combined with the pure oil density and pure water density obtained from sampling and analysis, the water content can be further estimated, thereby obtaining the pure oil yield and water production. The above calculation method can be selected according to the on-site metering requirements and does not limit the structural protection scope of this utility model.

[0029] For ease of transportation and on-site deployment, a steel frame can be installed on the outside of this device to house the metering tank shell 1 and pipelines. For cold-climate applications, electric heating tape can be laid on the metering tank shell 1, the inlet pipeline, and the outlet pipeline, with an insulation layer installed on the outside of the heating tape to reduce issues such as increased crude oil viscosity, waxing, or blockage caused by low temperatures.

[0030] This device has been practically applied in a test well in Daqing Oilfield. The equipment's temperature and pressure resistance meet the requirements, and its measurement range and accuracy have reached the design specifications. It has been running continuously without failure in the field for more than 130 days, proving that it has good reliability and practicality.

[0031] The various embodiments of this utility model have now been described in detail. To avoid obscuring the concept of this utility model, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0032] It should be noted that, in the description of this utility model, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationships, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0033] Furthermore, the terms "first," "second," and similar words used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range. Words such as "including" or "comprising" mean that the element preceding the word encompasses the element listed after it, and do not exclude the possibility of encompassing other elements as well.

[0034] It should also be noted that, in the description of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model depending on the specific circumstances. When a specific device is described as being located between a first device and a second device, an intermediary device may or may not be present between the specific device and the first or second device.

[0035] All terms used in this invention have the same meaning as understood by one of ordinary skill in the art to which this invention pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.

[0036] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0037] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any manner.

Claims

1. A dual-chamber alternating differential pressure crude oil metering device, characterized in that, include: A metering tank shell, wherein a partition is provided inside the metering tank shell, the partition extends upward from the bottom of the metering tank shell and divides the lower part of the metering tank shell into a first chamber and a second chamber, and an upper air-connected space is formed between the upper end of the partition and the top of the metering tank shell, which allows the first chamber and the second chamber to communicate with each other. The inlet pipe and the outlet pipe are respectively connected to the first chamber and the second chamber, and each of the inlet pipe and the outlet pipe is equipped with a valve; The differential pressure detection unit includes a first differential pressure detection unit connected to the first chamber and a second differential pressure detection unit connected to the second chamber. Each differential pressure detection unit has an upper detection port and a lower detection port. The lower detection port is set higher than the drain port of the corresponding chamber, so that the space in the corresponding chamber below the lower detection port and above the drain port forms a water seal reserved section. The liquid level detection unit includes a first liquid level detection unit disposed in the first chamber and a second liquid level detection unit disposed in the second chamber; The control unit is electrically connected to the valve, differential pressure detection unit, and liquid level detection unit. The control unit is configured to output valve opening and closing control signals based on the detection signals from the liquid level detection unit and the differential pressure detection unit, so that the first chamber and the second chamber are alternately connected to the inlet pipe and the outlet pipe, and the valve on the corresponding outlet pipe is closed when the liquid level in the corresponding chamber drops to a preset closing liquid level. The preset closing liquid level is not lower than the height of the lower detection port, so that liquid is retained in the water seal reserved section.

2. The dual-chamber alternating differential pressure crude oil metering device according to claim 1, characterized in that, The upper part of the metering tank shell is provided with a gas outlet that communicates with the upper gas connection space, and the gas outlet is connected to a gas flow meter.

3. The dual-chamber alternating differential pressure crude oil metering device according to claim 2, characterized in that, The metering tank is equipped with a mist eliminator inside its shell, which is located below the gas outlet.

4. The dual-chamber alternating differential pressure crude oil metering device according to claim 1, characterized in that, The differential pressure detection unit is a differential pressure sensor. The upper detection port and the lower detection port are spaced apart along the height direction of the corresponding chamber, and there is a preset height difference between the upper detection port and the lower detection port.

5. A dual-chamber alternating differential pressure crude oil metering device according to claim 4, characterized in that, The detection position of the liquid level detection unit is higher than the lower detection port, and a constant volume measurement section is defined between the detection position of the liquid level detection unit and the lower detection port in the corresponding chamber.

6. A dual-chamber alternating differential pressure crude oil metering device according to claim 5, characterized in that, The first chamber and the second chamber are arranged symmetrically from left to right, and their effective cross-sectional areas are the same. The first liquid level detection unit and the second liquid level detection unit are located at the same height, and the lower detection port of the first differential pressure detection unit and the lower detection port of the second differential pressure detection unit are located at the same height.

7. The dual-chamber alternating differential pressure crude oil metering device according to claim 1, characterized in that, The valve is an electric valve, and the control unit is a programmable logic controller located in a control box outside the metering tank shell.

8. A dual-chamber alternating differential pressure crude oil metering device according to claim 1, characterized in that, The drain lines of the first chamber and the second chamber merge into a main drain line downstream of the corresponding valve, and the inlet lines of the first chamber and the second chamber are connected to the main inlet line upstream of the corresponding valve.

9. A dual-chamber alternating differential pressure crude oil metering device according to claim 1, characterized in that, It also includes a steel frame for housing and supporting the metering tank shell.

10. A dual-chamber alternating differential pressure crude oil metering device according to claim 1, characterized in that, The outer walls of the metering tank shell, the inlet pipe, and the outlet pipe are all equipped with electric heating tapes, and the outer sides of the electric heating tapes are covered with a heat insulation layer.

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