A coal bed gas water production and gas production metering pry device

Abstract

The utility model discloses a coal bed gas water production gas production metering prying device, aims at solving the low precision of coal bed gas water production measurement, the low degree of automation and the poor working condition adaptability of prior art. The device includes: water storage tank, the drain line of water outlet connection with water storage tank, the flowmeter of setting on the drain line, the control valve of being located in the upstream of flowmeter and a control system. The control system is according to the water level in water storage tank, controls the control valve and carries out intermittent opening and closing, realizes batch type discharge and measurement of the water production, the drain line is set to have local high point downstream flowmeter, and the local high point is higher than flowmeter, forms siphon or stagnation effect during the discharge measurement, thereby ensuring that flowmeter is always in full pipe state of filling liquid and carries out measurement. The utility model through the intermittent drainage control of the buffer of water storage tank and control system, effectively coped with the problem of water production discontinuous, and the big flow fluctuation, improved the measurement precision.

Description

Technical Field

[0001] This utility model belongs to the field of coalbed methane extraction technology, and specifically relates to a coalbed methane water and gas production metering skid device. Background Technology

[0002] In the process of coalbed methane extraction, accurate and real-time measurement of produced water and gas is a key link in assessing the production dynamics of gas wells, optimizing extraction plans, and conducting refined production management. However, current measurement technologies for coalbed methane wells generally prioritize gas production over water production, especially when facing complex operating conditions such as unstable produced fluids, gas-liquid mixing, and large flow fluctuations (e.g., blockage flow), where mature and effective measurement methods are lacking.

[0003] Existing metering methods suffer from the following drawbacks: First, traditional manual metering methods, such as timed retrieval or estimation, are not only labor-intensive and resource-intensive, but also cumbersome, produce discontinuous data, and are prone to significant human error, failing to meet the demands of automated and continuous monitoring. Second, directly installing conventional water flow meters in pipelines is problematic when the output water volume is small, the flow rate is unstable, or the output contains gas; the flow meters struggle to operate under full-pipe conditions, leading to significant deviations in measurement readings and poor data reliability. Furthermore, some open metering devices using flapper level gauges suffer from losses due to liquid evaporation and overflow, and are particularly prone to freezing and blockage, especially in low-temperature winter environments, making them extremely inconvenient to use.

[0004] Meanwhile, some existing automated metering devices also have shortcomings in structural design and functional integration. For example, the pipeline design of some devices does not fully consider the necessary conditions for flow meter measurement, and the complex pipeline structure makes subsequent cleaning and maintenance difficult. In addition, many devices lack adaptive designs for changes in ambient temperature (such as antifreeze measures) and lack backup emergency access. Once a critical component (such as a valve) fails, the entire metering system may shut down, affecting normal production. Finally, most existing equipment has limited functions, lacks standardized data interfaces and intelligent control logic, and is difficult to integrate into modern production data acquisition and monitoring systems.

[0005] Therefore, how to provide a device that can overcome the above-mentioned defects, achieve high-precision, automated, and continuous metering of coalbed methane produced water, and at the same time have good adaptability to operating conditions, high reliability, and easy maintenance is a technical problem that urgently needs to be solved in this field. Utility Model Content

[0006] To address the aforementioned problems in the prior art, namely low metering accuracy, low automation, and poor adaptability to operating conditions in coalbed methane water production, this utility model provides a coalbed methane water and gas production metering skid device, which includes:

[0007] A water storage tank with an inlet and an outlet;

[0008] A drainage pipe is connected to the outlet of the water storage tank;

[0009] A flow meter is installed on the drainage pipe;

[0010] A control valve is installed on the drain pipe and located between the flow meter and the outlet of the water storage tank; and

[0011] A control system is used to control the control valve to open and close intermittently according to the water level in the water storage tank.

[0012] The drainage pipe is configured to have a local elevation point downstream of the flow meter, which is higher than the flow meter.

[0013] Furthermore, the control system includes: a level gauge installed on the water storage tank, and a control module electrically connected to the level gauge and the control valve respectively.

[0014] Furthermore, the control valve is a solenoid valve.

[0015] Furthermore, it also includes an automatic vent valve located on the top of the water storage tank.

[0016] Furthermore, the bottom of the water storage tank has a convex structure, and a drain outlet is provided at the lowest point of the convex structure.

[0017] Furthermore, it also includes an overflow prevention drainage pipeline, one end of which is connected to an overflow prevention drainage port opened on the water storage tank, and the other end of which is connected to a drainage pipeline and is set between the control valve and the flow meter. A manual vacuum ball valve is installed on the overflow prevention drainage pipeline.

[0018] Furthermore, it also includes:

[0019] Temperature sensor, used to sense ambient temperature; and

[0020] An electric heating device is installed on the outer wall of the water storage tank and the drainage pipe;

[0021] The temperature sensor and the electric heating device are both electrically connected to the control module.

[0022] Furthermore, the flow meter is an ultrasonic flow meter.

[0023] Furthermore, it also includes a skid-mounted base, on which the water storage tank and the drainage pipe are fixedly installed.

[0024] Furthermore, the water inlet of the water storage tank and the outlet of the drainage pipe are both connected by flexible hoses.

[0025] The beneficial effects of this utility model are:

[0026] In coalbed methane wells, common operating conditions such as intermittent flow and discontinuous production often result in flow meters operating in a partially full-pipe state, leading to significant measurement errors. This invention buffers the discontinuous inflow using a water storage tank, and then uses a control system to intermittently open and close downstream control valves based on water level, transforming the unstable inflow into a stable and controllable batch discharge. More importantly, by setting a local high point downstream of the flow meter, a physical liquid seal is created, forcibly ensuring that the flow meter's measuring section is always fully filled with liquid, regardless of whether the device is in a drainage state. This combined design fundamentally solves the core technical challenge of partially full-pipe metering, resulting in a qualitative leap in measurement accuracy and providing reliable data support for production decisions.

[0027] This invention establishes a complete closed-loop automatic control process by automatically monitoring the water level in the storage tank and controlling the opening and closing of the control valve through a control system. This solution completely replaces traditional manual estimation and on-site operation, which not only greatly saves labor costs but also completely avoids estimation and recording errors introduced by manual operation. It achieves continuous and accurate metering around the clock and without human intervention, improving the efficiency and automation level of production management.

[0028] This invention, particularly the buffering and peak-shaving function of the water storage tank, enables the device to effectively handle various complex operating conditions, such as changes from low to high production and drastic flow fluctuations. Whether it is a well with extremely low production requiring long-term accumulation for measurement, or a well with pulsed production, this device can stably and accurately complete the measurement task through an automatic accumulation and batch discharge mode, demonstrating strong versatility and application value. Attached Figure Description

[0029] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0030] Figure 1 This is a schematic diagram of the overall structure of the coalbed methane water production metering device provided in this embodiment of the utility model.

[0031] 1-Water storage tank; 2-Drainage pipe; 3-Flow meter; 4-Level gauge; 5-Control valve; 6-Control module; 7-Temperature sensor; 8-Electric heating device; 9-Skid-mounted base. Detailed Implementation

[0032] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0033] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0034] This utility model provides a specific embodiment of a coalbed methane water and gas production metering skid device, such as... Figure 1 As shown, the device includes: a water storage tank 1 with an inlet and an outlet; a drainage pipe 2 connected to the outlet of the water storage tank 1; a flow meter 3 installed on the drainage pipe 2 and located between the flow meter 3 and the outlet of the water storage tank 1; and a control system for controlling the control valve 5 to intermittently open and close according to the water level in the water storage tank 1; wherein, the drainage pipe 2 is configured to have a local elevation point downstream of the flow meter 3, the local elevation point being higher than the flow meter 3, such as... Figure 1 As shown in 'a'.

[0035] In this specific embodiment, the device aims to solve the metering inaccuracies caused by discontinuous water production, gas-liquid mixing, and large flow fluctuations, such as in intermittent flow conditions, in the prior art. Produced water from the coalbed methane well enters the storage tank 1 through the inlet. The storage tank 1 plays a crucial buffering and peak-shaving role, collecting the intermittent, pulsed fluid inflow from the wellhead. Its peak-shaving volume is designed with reference to the single full-capacity production of the downhole pump; for example, the volume of the storage tank 1 is designed to be greater than twice the single full-capacity production to effectively solve the problem of discontinuous water production. Inside the storage tank 1, utilizing the density difference between water and gas, the gas naturally rises to the top of the tank, while water and impurities such as coal dust remain at the bottom, achieving preliminary gas-liquid separation.

[0036] When the water level in the storage tank 1 reaches the preset height, the control system will open the control valve 5 located on the drain pipe 2. The water in the storage tank 1 flows into the drain pipe 2 through the outlet under the action of gravity, and flows through the flow meter 3 for measurement, and then is discharged through the control valve 5. When one discharge measurement process is completed and the control valve 5 is closed, because there is a local high point downstream of the flow meter 3 in the drain pipe 2, such as a gooseneck pipe or inverted U-shaped pipe structure that bends upward and then downward again, this local high point will form a liquid seal, so that liquid will always remain in the pipe section from the flow meter 3 to this local high point.

[0037] This design ensures that the measuring pipe section of flowmeter 3 is always full of liquid, regardless of whether the device is in a draining state, thus avoiding huge measurement errors caused by non-full pipe and ensuring high accuracy of data every time measurement is started.

[0038] In some preferred embodiments, the control system includes: a level gauge 4 disposed on the water storage tank 1, and a control module electrically connected to the level gauge 4 and the control valve 5 respectively.

[0039] Specifically, the control module can be a programmable logic controller (PLC) or a dedicated microcontroller. The level gauge 4 is preferably a hydrostatic level gauge, based on pressure sensor technology, capable of stably and accurately continuously monitoring the real-time liquid level in the water storage tank 1 and sending this level signal to the control module. The control module has two preset thresholds: an upper limit for the high liquid level and a lower limit for the low liquid level. When liquid continuously enters the water storage tank 1 from the wellhead, and the level gauge 4 detects a rise in the liquid level that reaches the preset upper limit, the control module outputs an opening signal to the control valve 5, causing it to open and initiating drainage metering.

[0040] As water is discharged, the liquid level in the tank drops. When the level gauge 4 detects that the liquid level has dropped to the preset low limit, the control module outputs a shut-off signal to the control valve 5, causing it to close. This intermittent working mode of cumulative batch discharge not only adapts to unstable influent conditions but also ensures that the flow rate and volume through the flow meter 3 are relatively stable during each discharge, remaining within the optimal metering range of the flow meter, thus improving metering accuracy.

[0041] Meanwhile, as an intelligent communication device, the control module is also responsible for collecting and storing flow data from flow meter 3, liquid level data from level meter 44, and other sensor data. Through its integrated Modbus unified communication interface, it uploads all data with planned storage addresses to the upper-level monitoring system to achieve unattended operation and intelligent management.

[0042] In some preferred embodiments, the control valve 5 is a solenoid valve.

[0043] To achieve fast and reliable on / off control and accurately match the commands issued by the control module, a solenoid valve is used as control valve 5. Driven by electromagnetic force, the solenoid valve offers advantages such as fast response, reliable operation, and long service life, making it ideal for the high-frequency, automated on / off cycles required by this device. Of course, in other embodiments, other types of automatic control valves, such as electric ball valves, can be selected based on cost and site requirements; however, compared to these options, the solenoid valve offers faster switching speeds and better guarantees precise start and stop of batch discharge.

[0044] In some preferred embodiments, an automatic vent valve is also provided on the top of the water storage tank 1.

[0045] The automatic vent valve is used to ensure stable pressure inside the water storage tank 1. During the gas-liquid separation process, gases such as coalbed methane released from the water accumulate in the upper space of the water storage tank 1. When the gas pressure reaches its opening threshold, the automatic vent valve will automatically open to release gas, thereby maintaining the tank at a near-normal pressure. This avoids excessive pressure inside the tank affecting subsequent liquid discharge and also eliminates the interference of pressure fluctuations on the measurement accuracy of the hydrostatic level gauge 4.

[0046] In some preferred embodiments, the bottom of the water storage tank 1 has a convex structure, and a drain outlet 6 is provided at the lowest point of the convex structure.

[0047] To address the potential sedimentation of solid impurities such as coal dust carried in the produced water over long-term operation, the bottom of the storage tank 1 is optimized with a downward-convex structure, such as a conical or dish-shaped bottom. This structure utilizes the principle of gravity settling, allowing denser impurities like coal dust to naturally slide off and accumulate near the lowest drain outlet 6 during water storage. Workers can periodically open the manual valve of drain outlet 6 to easily remove the sediment, greatly simplifying maintenance and preventing impurities from entering downstream pipelines and affecting the normal operation of the flow meter 3 and control valve 5.

[0048] In some preferred embodiments, an overflow prevention drainage pipe 7 is also included. One end of the overflow prevention drainage pipe 7 is connected to an overflow prevention drainage port opened on the water storage tank 1, and the other end of the overflow prevention drainage pipe 7 is connected to a drainage pipe 2 and is disposed between the control valve 5 and the flow meter 3. A manual vacuum ball valve 8 is installed on the overflow prevention drainage pipe 7.

[0049] The overflow drain outlet is positioned above the highest normal operating level. If the main control valve 5 fails to open, causing an abnormal rise in the water level in storage tank 1, liquid will automatically overflow through this pipeline, effectively preventing overflow accidents. The ingenious design lies in the fact that, because its outlet is connected after the flow meter 3 and before the control valve 5, even during emergency overflow via this bypass, the overflowing water will still flow through the flow meter 3, ensuring uninterrupted water production measurement and data integrity. Secondly, the manual vacuum ball valve 8 installed on the pipeline remains closed under normal operating conditions and is primarily used for equipment maintenance. When it is necessary to inspect, calibrate, or clean the pipeline, this valve can be operated to drain, inject water, or backflush a specific section of the pipeline, greatly improving the maintainability and ease of operation of the device.

[0050] In some preferred embodiments, the system further includes: a temperature sensor for sensing ambient temperature; and an electric heating device disposed on the outer wall of the water storage tank 1 and the drainage pipe 2; wherein the temperature sensor and the electric heating device are both electrically connected to the control module.

[0051] Considering the harsh winter environment often faced by coalbed methane extraction sites, this unit integrates an intelligent anti-freezing and insulation system to prevent equipment damage from freezing. This system includes a temperature sensor to detect ambient temperature and an electric heating device, such as an electric heating tape, installed on the outer walls of the water storage tank 1 and drainage pipe 2. The control module monitors the ambient temperature collected by the temperature sensor in real time. When the temperature falls below a preset anti-freezing threshold, such as 5°C, the electric heating device automatically activates for insulation; when the temperature rises above the threshold, the heating is automatically shut off. This achieves lean energy consumption control, ensuring reliable operation of the unit in winter while maximizing electricity savings.

[0052] In some preferred embodiments, the flow meter 3 is an ultrasonic flow meter.

[0053] The ultrasonic flow meter is chosen primarily because of its non-contact measurement characteristics. Its sensor probe is installed on the outer wall of the pipe, not in direct contact with the fluid, thus it is less susceptible to wear and clogging from impurities such as coal dust in the fluid, exhibiting strong anti-pollution capabilities and extremely low maintenance requirements. Furthermore, to facilitate maintenance or cleaning of the flow meter probe, a dedicated cleaning port can be designed at the rear end of the pipe section where the flow meter is located; this pipe section is preferably a straight-through structure.

[0054] Of course, the scope of protection of this utility model is not limited to ultrasonic flow meters, and other types of flow meters can also be selected in other variations. For example, a vortex flow meter can be selected, which has high accuracy in harsh environments, but requires regular cleaning; or a simple orifice plate flow meter can be selected, which has strong anti-pollution ability but lower measurement accuracy. Turbine flow meters are generally not recommended for use in this device because their turbine blades are easily worn by coal dust.

[0055] In some preferred embodiments, a skid-mounted base 9 is also included, on which the water storage tank 1 and the drainage pipe 2 are both fixedly installed.

[0056] To facilitate overall transportation, factory prefabrication, rapid on-site installation, and reuse across different well sites, the unit's overall structure adopts a skid-mounted design. All core components, including the water storage tank 1, drainage pipeline 2, and control cabinet 10 containing control modules, are pre-integrated and fixedly mounted on a robust steel skid base 9, forming a fully functional independent module. This design significantly reduces on-site installation and commissioning workload, achieving "plug and play," and greatly facilitating equipment relocation and reuse.

[0057] In some preferred embodiments, the inlet of the water storage tank 1 and the outlet of the drainage pipe 2 are both connected by flexible hoses.

[0058] To better adapt to the complex and varied pipeline connection conditions on site, such as varying wellhead outlet heights and uneven ground, the inlet of the water storage tank 1 and the final outlet of the drainage pipe 2 are both connected by flexible hoses. Using flexible hoses instead of traditional rigid pipes greatly improves installation flexibility and fault tolerance, and simplifies on-site pipeline laying.

[0059] In some preferred embodiments, a flow meter probe cleaning hole 11 is provided at the end of the drainage pipe 2.

[0060] In this embodiment, a flow meter probe cleaning hole 11 is also provided at the end of the drainage pipe 2. Considering that coalbed methane production water often contains impurities such as coal dust, which may adhere to the sensitive components of the flow meter after long-term operation, affecting measurement accuracy, this cleaning hole allows maintenance personnel to easily reach in through the reserved opening to directly clean and rinse the flow meter probe without disassembling the pipe or the flow meter body, quickly restoring it to its optimal working condition. This structural design greatly simplifies the difficulty and workload of on-site maintenance, effectively ensuring the accuracy and stability of the metering device during long-term operation.

[0061] In the description of this utility model, terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," which indicate direction or positional relationships, are based on the direction or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0062] Furthermore, it should 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 mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0063] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent in such process, method, article, or apparatus / device.

[0064] The technical solution of this utility model has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the protection scope of this utility model is obviously not limited to these specific embodiments. Without departing from the principle of this utility model, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of this utility model.

Claims

1. A coalbed methane water and gas production metering skid device, characterized in that, The device includes: Water storage tank (1) has an inlet and an outlet; The drainage pipe (2) is connected to the outlet of the water storage tank (1); A flow meter (3) is installed on the drainage pipe (2); A control valve (5) is installed on the drain pipe (2) and located between the flow meter (3) and the outlet of the water storage tank (1); and The control system is used to control the control valve (5) to open and close intermittently according to the water level in the water storage tank (1); The drainage pipe (2) is configured to have a local high point downstream of the flow meter (3), the local high point being higher than the flow meter (3).

2. The coalbed methane water and gas production metering skid device according to claim 1, characterized in that, The control system includes: a level gauge (4) installed on the water storage tank (1), and a control module electrically connected to the level gauge (4) and the control valve (5) respectively.

3. A coalbed methane water and gas production metering skid device according to claim 1 or 2, characterized in that, The control valve (5) is a solenoid valve.

4. The coalbed methane water and gas production metering skid device according to claim 1, characterized in that, It also includes an automatic vent valve located on top of the water storage tank (1).

5. A coalbed methane water and gas production metering skid device according to claim 1, characterized in that, The bottom of the water storage tank (1) has a convex structure, and a drain outlet (6) is provided at the lowest point of the convex structure.

6. The coalbed methane water and gas production metering skid device according to claim 1, characterized in that, It also includes an overflow drainage pipe (7), one end of which is connected to an overflow drainage port opened on the water storage tank (1), and the other end of which is connected to a drainage pipe (2) and is set between the control valve (5) and the flow meter (3). A manual vacuum ball valve (8) is installed on the overflow drainage pipe (7).

7. A coalbed methane water and gas production metering skid device according to claim 2, characterized in that, Also includes: Temperature sensor, used to sense ambient temperature; as well as An electric heating device is installed on the outer wall of the water storage tank (1) and the drainage pipe (2); The temperature sensor and the electric heating device are both electrically connected to the control module.

8. A coalbed methane water and gas production metering skid device according to claim 1, characterized in that, The flow meter (3) is an ultrasonic flow meter.

9. A coalbed methane water and gas production metering skid device according to claim 1, characterized in that, It also includes a skid-mounted base (9), on which the water storage tank (1) and the drainage pipe (2) are fixedly installed.

10. A coalbed methane water and gas production metering skid device according to claim 1, characterized in that, The inlet of the water storage tank (1) and the outlet of the drainage pipe (2) are both connected by flexible hoses.

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