CN207944918U - Controllable type slug flow generating apparatus - Google Patents

Abstract

The utility model relates to a controllable slug flow generating device, which comprises a slug generator and a console. The slug generator includes a gas phase channel and a gas-liquid mixing channel connected between the gas phase inlet and the slug outlet. Including the first slug chamber and the first quick-response valve with in-position signal feedback; the gas-liquid mixing channel sequentially includes the second quick-response valve with in-position signal feedback, gas-liquid mixer, second slug chamber, The third quick-response valve with in-position signal feedback and the fourth quick-response valve with in-position signal feedback are connected in parallel, the gas flowing out from the second quick-response valve with in-position signal feedback and the liquid flowing in from the liquid phase inlet Mixing in the gas-liquid mixer; under the control of the console for each quick-response valve and flow regulating valve, a slug flow is formed. The utility model is a slug flow generating device capable of simulating actual on-site working conditions.

Description

Controllable Slug Flow Generator

technical field

The utility model relates to a controllable slug flow generating device.

Background technique

Wet natural gas is a gas-liquid two-phase flow in which the gas phase is a continuous phase and the liquid phase is a discrete phase. The gas phase carries the liquid phase through the pipeline. In industrial processes such as natural gas collection and transportation, pipelines are often accompanied by liquid media such as condensate oil and formation water. For conventional high-pressure gas fields, during the life cycle of gas well production in the wellhead output, the downhole pressure gradually decreases, the gas liquid-carrying capacity becomes worse, and slug flow is easily formed during the wellhead gas production process. During the mining process of offshore platforms, serious slug flow will also be formed due to the existence of subsea risers. During the transportation of natural gas, slug flow will also be caused by the undulation of terrain.

The occurrence of slug flow will cause serious harm to wellhead production and transportation equipment, and even cause unpredictable safety accidents, which are mainly manifested in: (1) The impact on the gas production process. The appearance of slug flow can easily cause high pressure or high liquid level alarm of the on-site separator, which will reduce the separation efficiency; severe slug flow will even cause the separator to overflow and cause the liquid phase to directly flow into the gas circuit; (2) the conveying system The effect of the mixing pump. In many occasions, gas-liquid mixed transportation is used. Due to the frequent slug flow, the mixed transportation pump will work in the alternating load state for a long time. If the dry running time is too long, the meshing screw will be overheated and the service life of the mixed transportation pump will be reduced. and work efficiency; (3) the impact on sealing components. The gas-liquid two-phase mixed flow is different from pure gas-phase or liquid-phase transportation, and will put forward some special requirements for the seals. The impact load caused by the slug flow further deteriorates the working conditions of these components, not only affecting the performance of the seals. life, and it will lead to permanent failure of the seal, and the leakage of the sealing fluid will increase. If it cannot be dealt with in time, it may even cause a safety accident; Affect the normal operation of the equipment; (5) Impact on measurement accuracy. Due to the existence of slug flow, the flow in the pipeline will be extremely unstable. For multiphase flowmeters, the measurement accuracy cannot be guaranteed in this case; for separators, the separation cannot be guaranteed, resulting in single-phase flow installed downstream. The deviation of the flow meter measurement will affect the trade settlement.

At present, some companies and institutions at home and abroad have studied slug flow measurement, capture and slug flow generation. The mechanism of using the device to generate slug flow is based on the formation of natural flow or simulated topographic liquid slug, and the required pipeline length is often tens to thousands of meters. For example, the outdoor pipeline of the SINTEF test loop in Norway has a total length of 1000 meters, one of which has a horizontal tube length of 400 meters and a vertical tube height of 52 meters ^[1] ; the TUFFP test loop of the University of Tulsa in the United States is 420 meters long ^[1] ; The WASP test loop of the Institute of Science and Technology is 36 meters long ^[1] ; the test loop of the Institute of Mechanics of the Chinese Academy of Sciences is 40 meters long ^[1] ; the test pipeline of China University of Petroleum is 340 meters long ^[1] ; the test pipeline of the French Petroleum Research Institute is 50 meters long Mi ^[2] ; Patent No. CN2311758Y mentioned a principle of using multiple small gas-liquid separators to simulate the formation of slug flow ^[3] , and the patent also mentioned that this design method is suitable for vertical The flow in straight pipes is not suitable for horizontal pipes; China University of Petroleum also used the principle of a single separator to design artificial slug flow ^[4] . The liquid capacity means that the flow rate of the gas phase cannot be too small. At the same time, the formation of the liquid plug relies on the gravity of the liquid phase to flow down by itself, so the liquid plug is not controllable. The gas phase velocity of the slug flow device formed by natural flow is generally below 4m/s. When the gas phase velocity is too high, the slug flow cannot be formed; This type of device not only requires a long straight pipe section but also requires a certain height of the standpipe, and is prone to liquid phase blockage when the gas phase flow rate is small. In summary, the experimental device based on the general design is used to simulate the complex working conditions on site, which leads to the elimination of the laboratory design or the installation of the equipment for metering slug flow into the field pipeline that cannot meet the expected requirements.

references:

[1] Chen Zhenyu, He Limin. Research progress of slug flow test[J]. Oil and Gas Storage and Transportation, 2000,19(12):32-38.

[2]Vilagines R, Hall A R W.Comparative behavior of multiphase flowmeter test facilities[J].Oil&Gas Science&Technology,2006,58(58):647-657.

[3]. Dou Jianwen. A slug generating device and an oil-gas-water three-phase flow measuring device using the device: China, CN2311758Y[P]. 1999-03-24.

[4] Geng Geng, Limin He. Research on Velocity Characteristics of Slug Flow Plug in Down-dip Pipe[J]. Chemical Engineering, 2016,44(9):44-48.

Utility model content

In view of the above problems, the purpose of this utility model is to provide a slug flow generating device with a small footprint, simple construction, controllability, and the ability to simulate actual field conditions. The technical scheme of the utility model is as follows:

A controllable slug flow generating device, including a slug generator and a console, the slug generator includes a gas phase channel and a gas-liquid mixing channel connected between the gas phase inlet and the slug outlet, and the gas phase channel includes in turn The first slug chamber and the first quick-response valve with in-position signal feedback; the gas-liquid mixing channel includes the second quick-response valve with in-position signal feedback, gas-liquid mixer, second slug chamber, mutual The third quick-response valve with in-position signal feedback and the fourth quick-response valve with in-position signal feedback are connected in parallel, the gas flowing out from the second quick-response valve with in-position signal feedback and the liquid flowing in from the liquid phase inlet The gas-liquid mixer mixes; under the control of the console to each quick-response valve, a slug flow is formed.

The length and diameter of the two slug chambers can be switched. Flow regulating valves should be provided at the gas phase inlet and the liquid phase inlet respectively; a first transparent window should be arranged at the slug outlet, and a second transparent window should be arranged behind the second slug chamber.

The utility model is designed in combination with the characteristics of the actual working conditions of oil and gas well sites and transportation, and is not only suitable for newly-built two-phase flow devices but also suitable for partial transformation of existing two-phase flow devices.

Description of drawings

Fig. 1 Schematic diagram of the controllable slug flow generating device and its application scenarios.

Fig. 2 Schematic diagram of the structure of the slug generator.

Figure 3 is the effect diagram of slug formation. In the figure, t ₁ and t ₃ represent the time of valve action, that is, from fully open to fully closed or fully closed to fully open.

The reference signs are explained as follows:

1, 6: Slug chamber with switchable length and caliber

2, 3, 4, 8: Fast-response valves with in-position signal feedback

5: Gas-liquid mixer

7, 9: Transparent window

10, 11: flow control valve

Slug chamber 1 and slug chamber 6 can be equipped with telescopic joints with corresponding pipe diameters, which is convenient for installation and can also fine-tune the length of the slug. Transparent window 7 and transparent window 9 can be optional.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the content of the present utility model is described in detail.

As shown in Figure 1, the utility model mainly includes two parts: a slug flow generator and a console, and the rest includes standard meters, fans, water pumps, gas-liquid separators, etc. required to complete the overall functions of the system. The gas is sent in by the fan, and the liquid is sent in by the water pump. Among them, the slug flow generator includes four quick-response valves with in-position signal feedback and various straight pipe sections of different lengths and diameters to realize slug chambers of different volumes. The resulting slug flow is piped into the gas-liquid separator. An example of a fast-response valve with in-position signal feedback is used.

The actual steps are as follows:

First, four actions are defined for the convenience of the following description. Action A is defined as: quick response valves 2, 3, 4, and 8 are all opened; action B is defined as: quick response valves 4 and 8 are opened, and quick response valves 2 and 3 are closed; action C is defined as: quick response valves 4 and 8 are closed, and quick response valves 2 and 3 are opened; Action D is defined as: quick response valves 2, 3, 4 and 8 are all closed.

Actual working condition calculation example: Assume that the current working condition pipe diameter D is 0.05m, the gas phase inlet flow rate is 50m ³ /h, and the internal liquid storage space of the quick response valve body and the equivalent length of the gas-liquid mixer are 4D or 0.2m. To obtain a liquid slug length of 20D or 1m, a slug frequency of 0.05Hz, and an experiment time of 5min, the parameters to be set are divided into two parts. The position is adjusted to 16D or 0.8m, the on-off time interval of the quick-response valve is set to 20s, the flow rate of the liquid phase inlet is set to 0.353m ³ /h, and the experiment time is set to 5min.

Step 1: Execute Action A and Action D 3 times in total through the console to confirm whether the quick response valve in-position signal is normal;

Step 2: Set the flow rate of the liquid phase inlet to 0.353m ³ /h, and the flow rate of the gas phase inlet to 50m ³ /h;

Step 3: First execute action C, and when the console timing reaches 20s, automatically execute action B; after the console timing reaches 40s, execute action C again, and so on until the timing reaches 5 minutes, then execute action A;

Step 4: After the setting is completed, the console automatically performs timing, switching, and data collection tasks, and the operator can observe the effect of slug formation at the transparent windows 7 and 9;

Step 5: If safety accidents such as overpressure, overrun or blockage occur during the experiment, the console will automatically alarm and shut down immediately. If quick response valves 2, 3 and quick response valves 4, 8 cannot be closed at the same time, the control mode adopts interlocking. When the console changes the status of the quick response valves, it will first inquire about the in-position signal of each quick response valve. The console will open the quick response valve 2, 3 and close the quick response valve 4, 8 in the next step, but after the command to open the quick response valve 2, 3 does not receive the corresponding in-position signal, then the console will maintain Quickly respond to the current state of valves 4 and 8 and jump to open the alarm device at the same time to prompt the operator to quickly respond to valve failures.

In the above step 3, after performing action C, the slug chamber 6 starts to fill with liquid, at this time the gas phase enters the transparent window 9 through the slug chamber 1 and the quick response valve 2, and the transparent window 9 is in a state of pure gas at this time , while the liquid phase enters the slug chamber 6 through the gas-liquid mixer 5, and after the timing is up, action B is executed. At this time, the quick response valves 2 and 3 are closed, the quick response valves 4 and 8 are opened, and the gas phase can only pass through the quick response valves 4 and the gas-liquid mixer 5 flow downstream, and at the same time push the full pipe liquid in the slug chamber 6 to flow downstream. At this time, the state of the full pipe liquid can be seen in the transparent window 9, and thus reciprocate to form a slug flow.

The utility model has the following advantages due to the adoption of the above technical scheme:

(1) In terms of device volume, in the utility model, there is no rigid requirement for the length of the straight pipe section or the height of the standpipe, and the design is compact, so that the space occupied by the device is as small as possible;

(2) The length and volume of the slug generated by the device are controllable, adjustable, and can be switched automatically;

(3) The frequency and length of the slug produced by the device are controllable. The time required for the formation of the slug body is calculated according to the set frequency, and the required flow rate is calculated according to the length, pipe diameter and time of the slug body. It can be controlled by platform for flow regulation;

(4) The construction of the device is simple. It can be directly modified on the existing two-phase flow device to save costs, and can be added to the newly designed device;

(5) The device is equipped with a dedicated upper computer operating system. After installing the pipeline, the operator can complete all functions on the console, including start-up test, parameter setting, real-flow calibration, data storage and other functions.

According to the above embodiments, the finally obtained slug flow effect diagram is shown in FIG. 3 .

Claims (4)

1. A controllable slug flow generating device, comprising a slug generator and a console, said slug generator comprising a gas phase channel and a gas-liquid mixing channel connected between the gas phase inlet and the slug outlet, characterized in That is, the gas phase channel sequentially includes the first slug chamber and the first quick-response valve with in-position signal feedback; the gas-liquid mixing channel sequentially includes the second quick-response valve with in-position signal feedback, the gas-liquid mixer, the second The slug chamber, the third quick-response valve with in-position signal feedback and the fourth quick-response valve with in-position signal feedback are connected in parallel, the gas flowing out from the second quick-response valve with in-position signal feedback and the flow from the liquid The liquid flowing into the phase inlet is mixed in the gas-liquid mixer; under the control of the console to each quick-response valve and flow regulating valve, a slug flow is formed. 2. The controllable slug flow generating device according to claim 1, characterized in that the length and diameter of the two slug chambers can be switched. 3. The controllable slug flow generating device according to claim 1, characterized in that flow regulating valves are respectively arranged at the gas phase inlet and the liquid phase inlet. 4. The controllable slug flow generating device according to claim 1, characterized in that a first transparent window is provided at the slug outlet, and a second transparent window is provided behind the second slug chamber.