RU2799026C1 - Method and device for studying the movement of gas-liquid mixtures in wells, as well as flowlines and pipelines from wells - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: operation of gas, gas condensate and oil wells. A stand for studying the movement of gas-liquid mixtures in wells, as well as flowlines and pipelines from wells, consists of an experimental string, divided into sections using profile elements, a casing, a device for introducing an experimental mixture into the string and removing it from it, a separator, a supply and control unit for liquid flow rate, gas flow supply and control unit, gas-liquid mixture temperature control and adjustment unit, coolant temperature control and adjustment unit, gas and liquid flow meters, gas supply pipeline to the experimental string, liquid supply pipeline to the string, gas circulation devices, filter element, a block for monitoring and adjusting the set pressure in the device, pressure sensors at the inlet and outlet of the experimental string, a pipe for draining liquid from the stand, shutoff equipment, a pipeline for supplying liquid to the stand, as well as pressure and temperature sensors for measuring pressure losses along the length of the experimental string.

EFFECT: method for studying the movement of gas-liquid mixtures in wells, as well as flowlines and pipelines from wells, consists in that the experimental string is set in the required position, the required gas and liquid flow rates are set, the gas-liquid flow is injected into the experimental string, the gas-liquid mixture is circulated in a closed cycle, control the characteristics of the gas-liquid mixture and maintain them at a given level, change the pressure and temperature along the experimental string and at the end of the specified period of time evaluate the pressure loss in the experimental string as the difference between the pressure values at the inlet and outlet of the experimental string.

6 cl, 1 dwg

Description

The group of inventions relates to the oil and gas industry and can be used in the operation of gas, gas condensate and oil wells.

From the prior art, a 3D model of a stand for experimental study of the dynamic characteristics of high-pressure hoses (HPR) is known - “Bench for experimental study of the dynamic characteristics of flexible pipelines”, V.P. Purdik, M.Yu. Pozdnyakov, Journal of Science Practice VNTU, 2013, No. 1.

The disadvantages of this analogue are:

1. The impossibility of studying pipelines that have a different profile (ascending, descending, combined).

2. There is no possibility of modeling the movement of mixtures in the tested pipe.

The prior art stands for the study of non-stationary processes in the pressure pipelines of hydrotransport systems - copyright certificate for the invention No. 965919.

The disadvantages of this analogue are:

1. There is no possibility of conducting studies with a high content of the gas phase in the flow.

2. The impossibility of studying pipelines that have a different profile (ascending, descending, combined).

From the prior art, a stand is known for studying the dynamics of gas-saturated and two-phase gas-liquid flows in relief pipelines - RF patent for invention No. 2018800.

From the prior art, a hydrodynamic stand for simulating the operation of horizontal oil and gas wells is known - RF patent for utility model No. 134579.

The closest to the proposed solution is a stand for modeling the processes of flow of obliquely directed gas-liquid flows - RF patent for invention No. 2641337.

The disadvantages of these analogues are:

1. There is no possibility of maintaining a constant temperature of the gas-liquid mixture at the inlet to the experimental columns (during the long-term operation of the stand, the temperature of the gas-liquid mixture will constantly increase due to the operation of the equipment) and constant pressure, which negatively affects the results of the experiments.

The proposed technical solution differs from the analogue in that:

1. Makes it possible to maintain a constant temperature of the gas-liquid mixture at the inlet to the experimental columns.

2. It makes it possible to maintain a constant pressure of the gas-liquid mixture at the inlet to the experimental columns.

3. Allows you to avoid the influence of the environment on the results of the experiment.

The aim of the invention is to improve the quality of the study of gas-liquid flows.

The technical result of the inventions is to improve the quality of the study of gas-liquid flows, by improving the accuracy of the experiments by monitoring and maintaining during the experiment the temperature of the gas-liquid mixture in a given range at the inlet to the experimental columns, as well as expanding the functionality, by providing the possibility of visualization with improved quality of the processes occurring in the volume and along the length of the pipe string and pipeline.

A device (stand) for studying the movement of gas-liquid mixtures in wells, as well as loops and pipelines from wells (figure 1) consists of:

- experimental column (1), divided into a different number of sections, interconnected by means of profile elements (2), which allow modeling different sections (ascending and descending);

- casing (3), forming a cavity between the experimental column and the casing to create conditions for gas circulation in order to avoid the influence of the environment and maintain a constant temperature in the cavity. The casing can be made of soft (flexible) heat-insulating material, for example, K-Flex;

- devices for input (4) into the column and removal (5) from the experimental column of the gas-liquid mixture. At the same time, conditions are created in the input device (4) for bubbling the liquid with a gas stream supplied to the experimental column;

- separator (6) for separating the gas-liquid mixture;

- unit for supplying and controlling the flow of liquid (7);

- a gas flow supply and control unit (8), consisting of a device (15) for gas circulation (compressor), high-pressure gas supply (21) and discharge (22) pipelines, control valves (23) and (24);

- a unit for monitoring and regulating the temperature of the gas-liquid mixture (9), consisting of a heat exchanger (29), a heater (31) or a cooler, depending on the nature of the heat exchange (it is required to heat or cool), a coolant circulation device (33), which can be presented in the form pump or compressor (depending on the nature of the coolant - liquid or gas), a unit for monitoring and regulating the temperature of the gas in the experimental column (35) (the control unit (temperature controller) can be, for example, a temperature controller (thermostat) TZN4 or a temperature controller RT- 820M and others), temperature sensor (37);

- unit for monitoring and regulating the temperature of the heat carrier (10) in the casing, consisting of a heat exchanger (30), a heater (32) or a cooler, depending on the nature of the heat exchange (it is required to heat or cool), a heat carrier circulation device (34), which can be presented in in the form of a pump or compressor (depending on the nature of the coolant - liquid or gas), a gas temperature control and regulation unit in the casing (36) (the temperature controller can be, for example, a temperature controller (thermostat) TZN4 or a temperature controller RT-820M, etc. ), temperature sensor (38);

- liquid flow meter (12);

- gas supply pipeline (13) to the experimental column;

- liquid supply pipeline (14) to the experimental column;

- devices (15) and (16) for gas circulation (compressor);

- a filter element (17) to prevent particles from entering the gas circulation device (15);

- block of control and regulation (maintenance) of the set pressure in the stand (18);

- pressure sensors at the inlet (19) and outlet (20) of the experimental column;

- pipe for draining liquid from the stand (25);

- stop valves (26), (28), (39), (40);

- pipeline for supplying liquid to the stand (27);

- pressure and temperature sensors for measuring pressure losses along the length of the experimental column (not shown in the diagram).

The study of the movement of gas-liquid mixtures consists in the fact that the experimental column is set in the required position, the required gas and liquid flow rates are set, the gas-liquid flow is injected into the experimental column, then the gas-liquid mixture is circulated in a closed cycle, the characteristics of the gas-liquid mixture are controlled and maintained at a given level, changing the pressure and temperature along the experimental column, and at the end of a predetermined period of time, the pressure loss in the experimental column is estimated as the difference between the pressure values at the inlet and outlet of the experimental column.

The connecting elements can be made both in the form of a rigid structure and in the form of a flexible structure (for example, using high-pressure hoses - HPH). The connection between the section of the column and the connecting element can be carried out, for example, by means of threaded, flanged connections or by using quick couplings. Columns can be fastened, for example, to various metal structures, or with the help of retaining elements (pedestals). The experimental string can be placed both in a horizontal position (to conduct studies of various operating modes of pipelines and loops), as well as in a vertical and inclined position (to conduct studies of various operating modes of wells).

The fluid entering the bench system is supplied either from a reservoir (tank) or directly from the cold water pipeline line (cold water supply system). Therefore, the temperature of the incoming liquid can vary by tens of degrees (the temperature difference between the “summer-winter” periods is especially characteristic; in most cases, it is necessary to heat the gas-liquid mixture). In this regard, it becomes necessary to control and maintain the temperature of the gas-liquid mixture within the limits specified by the experimental conditions. In this case, during the experiments, the temperature of the gas-liquid mixture can change due to the processes associated with friction.

A device for studying the movement of gas-liquid mixtures in wells, as well as loops and pipelines from wells (see Fig. ) differs from analogues in that it contains:

- casing (3), forming a cavity between the experimental column and the casing to create conditions for gas circulation in order to avoid the influence of the environment and maintain a constant temperature in the cavity;

- unit for monitoring and regulating the temperature of the gas-liquid mixture (9);

- unit for monitoring and regulating the temperature of the coolant in the casing (10);

- a control and regulation unit (maintenance) of a given pressure in the stand - (18) (a control unit (pressure regulator) can be represented, for example, by types RDSG, RDGB, RDGD, RGDK, RD, etc.)

The device works as follows. Before assembling the system, the units are tested for strength (documentation must be available confirming the hydrotesting). Mount (set) the experimental column of the required length, the required profile (descending, ascending, combined), which is created by profile elements (2), and in the desired position (vertically, obliquely or horizontally). The casing (3) is mounted and the process lines (pipelines) are connected according to the diagram (for ease of installation, the connecting pipelines can be made of flexible pipelines on quick couplings). Close the stop valve (40) and open the stop valve (39). The stand is connected to a high-pressure gas source by a gas supply pipeline to the stand (21).

The control unit (18) is set to the set value of pressure required for the experiment at the inlet to the experimental column (1) or at the outlet of it. The control unit (18) interrogates one of the pressure sensors (19) or (20) and in case of a discrepancy between the set pressure value and the measured one by an amount exceeding the specified interval, it applies a control action to the control valve (23) to open. Gas starts to flow into the stand. With a given time interval, the control unit (18) interrogates one of the sensors (19) or (20) and, when the set value is reached in the stand, sends a control action to the control valve (24) to close. Thus, in automatic mode, the work of maintaining the set pressure value during the operation of the bench takes place, at which the gas pressure in the bench system is measured. If the measured value of the gas pressure deviates from the pressure specified according to the conditions of the experiment, the control unit (18) creates a control action on the control valve (23), which opens and pumps gas into the stand, or on the control valve (24), which opens and discharge of gas from the stand. Thus, the pressure value in the system of the stand is maintained in the range specified by the conditions of the experiment. The control action, for example, can be electrical or pneumatic.

After the gas pressure in the stand reaches the set value, the compressor (15) is switched on, while the gas from the separator (6) is sucked into the compressor (15), and then fed through the gas flow measurement device (11) and the inlet device into the column of gas-liquid mixture (4). The gas entering the experimental column (1) moves through it and through the device (5) for removing the gas-liquid mixture from the column through the pipeline enters the separator (6), and then into the compressor (15). The gas filling the stand begins to circulate around the stand in a closed cycle.

The required amount of liquid is supplied to the unit for supplying and controlling the flow of liquid (7) through the pipeline for supplying liquid to the stand (27) by opening the shutoff valve (28). After that, the shut-off valve (28) closes. Further, the liquid through the device for measuring the liquid flow (12) enters the device for introducing the gas-liquid mixture into the column (4), in which the liquid is mixed with gas (bubbling) and the gas-liquid mixture moves through the column (1) under the action of gas pressure. Having reached the end of the experimental column (1), the gas-liquid mixture first enters the gas-liquid mixture outlet device (5), and then enters the separator (6) through the connecting pipeline. Depending on the purpose of the experiment, tests can be carried out only with a liquid or with a liquid containing mechanical impurities (for example, sand). Mechanical impurities are added at the entrance to the experimental column along with the liquid in order to simulate the movement of a three-phase mixture (gas - water - sand). In this case, a special pumping unit is used as part of the fluid supply and control unit, for example, G15XDBGHFECA.

In the separator, the liquid is separated from the gas and flows down through the pipeline (14) to the liquid supply and control unit (7), and the gas through the pipeline (13) to the compressor (15). At the same time, a filter element (17) can be additionally installed on the pipeline (13) in order to reduce the risk of particles entering the compressor (15). Thus, the liquid circulates in a closed cycle.

In this case, the unit for monitoring and maintaining the temperature of the gas-liquid mixture (9) operates in automatic mode, in which the temperature of the gas entering the experimental column (1) is measured by means of a temperature sensor (37), and this value is transmitted to the control unit (35) . If the measured temperature value deviates from the temperature set according to the conditions of the experiment, the control unit (35) creates a control action on the coolant circulation device (33), which circulates the coolant from the heater (or refrigeration chamber) (31) to the heat exchanger (29) and back. Thus, due to the heat exchange between the coolant and the gas in the heat exchanger housing (29), the temperature is maintained in the range specified by the experimental conditions. The coolant can be air, water, etc. When the temperature is higher than the set value by the set value, the control unit (35) creates a control action on the heat carrier circulation device (33), which stops the heat carrier circulation from the heater (or refrigeration chamber) (31) to the heat exchanger (29) and back. Thus, due to the creation and termination of the circulation of the coolant, the temperature is maintained within the specified range.

The block for monitoring and regulating the temperature of the coolant (10) in the casing (3) works in exactly the same way in order to provide conditions that allow excluding the influence of ambient air on the results of the experiment. Given that the experimental column has an extended length (tens of meters or more), it is located in the open air, where the environment affects the heat transfer processes. This is especially true in windy weather and the cold season. Therefore, it is advisable to separate the communication of the pipe surface with the environment by creating a cavity in which a given temperature is maintained.

After the end of the experiment, the gas is released from the stand through the gas discharge pipeline from the stand (22), by opening the control valve (24), the liquid is drained through the drain pipe (25) with a shut-off device (26) located at the inlet to the experimental column - the input device to the column of gas-liquid mixture (4).

In this case, taking into account the complex profile of the column, part of the liquid may remain in certain sections of the experimental column (1). To do this, the nodes of the experimental column (1) of the stand are “dryed” by circulating gas through the experimental column (1) into the atmosphere. To do this, close the shut-off valve (39) and open the shut-off valve (40) and (26) and the control valve (23). Gas through the high-pressure gas supply pipeline (21) through the compressor (15) enters the gas-liquid mixture removal device (5), from where part of the gas passes through the experimental column (1) and is blown out into the atmosphere through the liquid drain pipe (25), and the rest part enters the separator (6) and is forced back into the compressor (15). Thus, the units and pipelines of the stand are “purged from the end to the beginning” from the remaining liquid for 10-20 minutes. Because part of the gas circulates in a closed cycle, this contributes to an increase in air temperature, which leads to a more intensive absorption of liquid from the inner surface of the stand. After that, the compressor (15) is switched off, the shut-off devices (26), (40) and the control valve (23) are closed, and the shut-off device (39) is opened.

During a specific experiment, pressures are measured in given sections of the column (1) with pressure gauges or differential pressure gauges. Having performed the required measurements, the technological parameters of the stand operation mode are changed: pressure, gas flow rates - using the compressor (15), and liquid - using the fluid supply and control unit (7) or stop the stand operation by removing the liquid from the column to the disposal system.

Claims (7)

1. A device for studying the movement of gas-liquid mixtures in wells, as well as loops and pipelines from wells - a stand, is characterized by the fact that it consists of an experimental column enclosed in a casing and divided into a different number of sections that are connected using profile elements; devices for input into the column and removal from it of the gas-liquid mixture; separator; node for supplying and regulating the flow of liquid; gas supply and control unit, consisting of a gas circulation device, gas supply and discharge pipelines, control valves; a unit for monitoring and regulating the temperature of the gas-liquid mixture, consisting of a heat exchanger, depending on the nature of the heat exchange of the heater or cooler, a heat carrier circulation device, a gas temperature control and adjustment unit and a temperature sensor; unit for monitoring and adjusting the temperature of the coolant, consisting of a heat exchanger, depending on the nature of the heat exchange of the heater or cooler, a coolant circulation device, a unit for monitoring and adjusting the gas temperature in the casing and a temperature sensor; gas and liquid flow meters; gas supply pipeline to the experimental column; pipeline for supplying liquid to the column; devices for gas circulation; filter element; block of control and regulation of the set pressure in the device; pressure sensors at the inlet and outlet of the experimental column; pipe for draining liquid from the stand; locking equipment; pipeline for supplying liquid to the stand; as well as pressure and temperature sensors for measuring pressure losses along the length of the experimental column. 2. The device of claim 1, characterized in that the connecting elements are made of a flexible material. 3. A method for studying the movement of gas-liquid mixtures in wells, as well as loops and pipelines from wells, which consists in the fact that the experimental column is set in the required position, the required gas and liquid flow rates are set, the gas-liquid flow is injected into the experimental column, the gas-liquid mixture is circulated along closed cycle, control the characteristics of the gas-liquid mixture and maintain them at a given level, change the pressure and temperature along the experimental column and at the end of a given period of time evaluate the pressure loss in the experimental column as the difference between the pressure values at the inlet and outlet of the experimental column. 4. The method according to p. 3, characterized in that the experimental column is installed in a vertical position. 5. The method according to p. 3, characterized in that the experimental column is installed in a horizontal position. 6. The method according to p. 3, characterized in that the experimental column is installed in an inclined position. 7. The method according to claim 3, characterized in that, depending on the purpose of the experiment, mechanical impurities, such as sand, are additionally fed into the experimental column along with the liquid in order to simulate the movement of a three-phase gas-water-sand mixture.

Images