Gas content regulation and control system and method based on oil-gas-water multiphase flow

Abstract

The invention relates to the technical field of oil-gas-water multiphase flow metering, in particular to a gas content regulation and control system and method based on oil-gas-water multiphase flow. The system comprises a flow supply unit, a mixing unit, an angle simulation unit, a pipe diameter simulation unit and a master control unit, the master control unit controls the flow supply unit to output one or more media with preset flow and transmits the media to the pipe diameter simulation unit, or controls the media to pass through the mixing unit and / or the angle simulation unit and then transmit the media to the pipe diameter simulation unit; the mixing unit mixes two-phase or three-phase media entering the mixing unit, the angle simulation unit enables the media output by the flow supply unit or the mixing unit to flow through a preset incident angle pipeline and then enter the pipe diameter simulation unit, and the pipe diameter simulation unit enables the media entering the pipe diameter simulation unit to pass through pipelines with different pipe diameters and then output. The problem that the finally measured gas content cannot meet the test requirement due to the fact that existing multiphase flow gas content regulation and control cannot accurately simulate the on-site multiphase flow forming process is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of oil-gas-water multiphase flow metering, and particularly to a gas holdup regulation system and method based on oil-gas-water multiphase flow. Background Art

[0002] The accurate detection of multiphase flow process parameters has become the core concern in oil and gas industrial production and scientific research. Multiphase flow refers to the coexistence of two or more different types of fluids in a system, such as oil phase, gas phase, and water phase. The unique properties of this fluid combination make multiphase flow exhibit complexity and diversity in the oil and gas production process.

[0003] The gas holdup in multiphase flow process parameters is an important basis for judging the flow pattern. Therefore, it is necessary to regulate the formation process of multiphase flow under various complex influencing factors on-site through simulation, so as to accurately measure the gas holdup under the simulated conditions, and then analyze the relationship between water cut and flow pattern.

[0004] In the current gas holdup regulation technology, conventional methods are mainly based on the operation of gas-liquid mixers. Specifically, by increasing or decreasing the gas flow rate in the multiphase mixed fluid, the gas holdup of the mixed fluid is increased or decreased. In addition, by changing the internal design of the mixer, such as its geometric shape and internal structure, the mixing efficiency of gas and liquid can also be affected, thereby indirectly controlling the gas holdup.

[0005] However, these methods can only adjust the gas content under different media and flow rate mixing conditions, and cannot regulate the gas holdup under other complex environmental influencing factors on-site, such as different incident angles and pipe diameters. Therefore, in order to accurately determine the multiphase flow pattern, it is necessary to design a stable, reliable, accurate, and efficient multifunctional gas holdup regulation system. Summary of the Invention

[0006] The present invention provides a gas holdup regulation system and method based on oil-gas-water multiphase flow to solve the problem that the existing regulation of multiphase flow gas content cannot accurately simulate the on-site multiphase flow formation process, resulting in the final measured gas content not meeting the test requirements.

[0007] According to one aspect of the present invention, a gas holdup regulation system based on oil-gas-water multiphase flow is provided, including: a flow supply unit, a mixing unit, an angle simulation unit, a pipe diameter simulation unit, and a total control unit; The total control unit is respectively connected to the flow supply unit, the mixing unit, the angle simulation unit, and the pipe diameter simulation unit; The total control unit is used to control the flow supply unit to output one or several media with a predetermined flow rate and transmit them to the pipe diameter simulation unit, or to control the transmission to the pipe diameter simulation unit after passing through the mixing unit and / or the angle simulation unit; The mixing unit is used to mix the two-phase or three-phase medium entering it, and the angle simulation unit is used to make the medium output by the flow supply unit or the mixing unit flow through a predetermined incident angle pipeline and then enter the pipe diameter simulation unit, and the pipe diameter simulation unit is used to output the medium entering it after passing through pipelines with different pipe diameters.

[0008] Preferably, the flow supply unit includes: a liquid delivery pipeline, a gas delivery pipeline, a data acquisition unit, and a flow control unit; The inlets of the liquid delivery pipeline and the gas delivery pipeline are connected to the corresponding medium sources, and the outlets are connected to the total control unit; Corresponding first switching valves are respectively arranged on the liquid delivery pipeline and the gas delivery pipeline, and the first switching valves are connected to the total control unit; The data acquisition unit is respectively connected to the liquid delivery pipeline and the gas delivery pipeline. The data acquisition unit is used to detect the real-time flow rates of the liquid and / or gas in the liquid delivery pipeline and / or the gas delivery pipeline and transmit them to the total control unit; The flow control unit is respectively connected to the liquid delivery pipeline and the gas delivery pipeline. The total control unit is used to adjust the real-time flow rates of the liquid in the liquid delivery pipeline and / or the gas in the gas delivery pipeline through the flow control unit.

[0009] Preferably, the data acquisition unit includes: a liquid flow sensor and a gas flow sensor; A liquid flow sensor for detecting the real-time flow rate of the liquid inside it is arranged between the switching valve and the outlet on the liquid delivery pipeline; A gas flow sensor for detecting the real-time flow rate of the gas inside it is arranged between the switching valve and the outlet on the gas delivery pipeline; The liquid flow sensor and the gas flow sensor are connected to the total control unit.

[0010] Preferably, the flow control unit includes: a liquid flow regulating valve and a gas flow regulating valve; A liquid flow sensor for detecting the real-time flow rate of the liquid inside it is arranged between the liquid flow sensor and the outlet on the liquid delivery pipeline; A gas flow sensor for detecting the real-time flow rate of the gas inside it is arranged between the gas flow sensor and the outlet on the gas delivery pipeline; The liquid flow sensor and the gas flow sensor are connected to the total control unit.

[0011] Preferably, the angle simulation unit includes: a plurality of incident angle pipelines and an angle control unit; The inlet of the incident angle pipeline is connected to the total control unit, and the outlet is connected to the pipe diameter simulation unit; The included angle between the outlet of each incident angle pipeline and the horizontal line at the inlet of the pipe diameter simulation unit is a predetermined incident angle, and the predetermined incident angles corresponding to each incident angle pipeline are different; The angle control unit is connected to the incident angle pipeline, and the angle control unit is used to control the medium to enter the incident angle pipeline corresponding to the predetermined incident angle.

[0012] Preferably, the angle control unit includes: a second switching valve; Each incident angle pipeline is respectively provided with a corresponding second switching valve, and the second switching valve is connected to the total control unit.

[0013] Preferably, the mixing unit includes: a liquid mixer and a gas-liquid mixer; The inlet of the liquid mixer is connected to the total control unit, the outlet is connected to the gas-liquid mixer, and the outlet of the gas-liquid mixer is connected to the total control unit; The liquid mixer is used to mix the liquid entering its interior, and the gas-liquid mixer is used to mix the liquid and gas entering its interior; The inlets and outlets of the liquid mixer and the gas-liquid mixer are respectively connected to the total control unit.

[0014] Preferably, the total control unit includes: a first connection pipeline, a single-phase medium switching valve, a gas mixing switching valve, a right switching valve for the incident angle pipe section, a left switching valve for the incident angle pipe section, and a test switching valve; The liquid delivery pipeline is connected to the liquid mixer, and the gas-liquid mixer is connected to the pipe diameter simulation unit through the test switching valve; The gas delivery pipeline is connected to the angle simulation unit through the right switching valve for the incident angle pipe section, and the angle simulation unit is connected to the pipe diameter simulation unit; One end of the first connection pipeline is in pipeline communication between the liquid delivery pipeline and the liquid mixer, and the other end of the first connection pipeline is in pipeline communication between the gas-liquid mixer and the test switching valve. A single-phase medium switching valve is provided on the first connection pipeline; One end of the gas mixing switching valve is in pipeline communication between the liquid mixer and the gas mixer, and the other end of the gas mixing switching valve is in communication with the gas delivery pipeline; One end of the left switching valve for the incident angle pipe section is in pipeline communication between the gas-liquid mixer and the test switching valve, and the other end of the left switching valve for the incident angle pipe section is in pipeline communication with the gas delivery pipeline between the gas mixing switching valve and the right switching valve for the incident angle pipe section.

[0015] Preferably, the medium includes liquid and / or gas; The liquid in the medium is: oil and / or water; and / or, the gas in the medium is: natural gas.

[0016] According to one aspect of the present invention, a method for regulating the gas holdup based on oil-gas-water multiphase flow is provided, including: Obtaining the parameters required for the simulation environment when measuring the test gas holdup, including the type of medium, the predetermined flow rate corresponding to each medium, and when there is an incident angle in the simulation environment, the corresponding predetermined incident angle value; The total control unit controls the flow supply unit to start, outputs the medium of the obtained predetermined flow rate and type. If the type of medium is one, the total control unit controls to transmit the medium to the pipe diameter simulation unit; If the type of medium is two or more, the total control unit controls to transmit the medium output by the flow supply unit to the mixing unit, and the mixing unit mixes two or more media and then transmits them to the pipe diameter simulation unit; If there is an incident angle in the simulation environment, the total control unit controls to transmit the medium output by the flow supply unit or the mixed medium output by the mixing unit to the angle simulation unit, and the angle simulation unit makes the medium flow through the pipeline corresponding to the predetermined incident angle value and then inputs it into the pipe diameter simulation unit.

[0017] The present invention has at least the following beneficial effects: The present invention provides a system and method for regulating the gas holdup based on oil-gas-water multiphase flow. By setting a flow supply unit, a mixing unit, an angle simulation unit, a pipe diameter simulation unit, and a total control unit, it can accurately simulate the formation process of multiphase flow under various on-site influencing factors, enhance the flexibility and adaptability of regulation, and better meet the professional requirements under different working conditions. Description of the Drawings

[0018] The drawings here are incorporated into the specification and form a part of this specification. These drawings show embodiments in line with the present invention and are used together with the specification to illustrate the technical solutions of the present invention.

[0019] Figure 1 Showing a schematic structural diagram of a system for regulating the gas holdup based on oil-gas-water multiphase flow according to an embodiment of the present invention.

[0020] In the figure, 1 - oil switch valve, 2 - oil flow sensor, 3 - oil flow regulating valve, 4 - water switch valve, 5 - water flow sensor, 6 - water flow regulating valve, 7 - natural gas switch valve, 8 - natural gas flow sensor, 9 - natural gas flow regulating valve, 10 - oil pipeline, 11 - water pipeline, 12 - natural gas pipeline, 13 - oil-water mixer, 14 - gas-liquid mixer, 15 - single-phase medium switch valve, 16 - first connecting pipeline, 17 - test switch valve, 18 - gas mixture switch valve, 19 - left switch valve of incident angle pipe section, 20 - right switch valve of incident angle pipe section, 21 - 30° incident angle pipe section switch valve, 22 - 45° incident angle pipe section switch valve, 23 - 60° incident angle pipe section switch valve, 24 - 30° incident angle pipeline, 25 - 45° incident angle pipeline, 26 - 60° incident angle pipeline, 27 - test pipe section, 28 - DN50 pipe diameter change section, 29 - DN80 pipe diameter change section, 30 - DN100 pipe diameter change section, 31 - incident pipeline. Detailed implementation manners

[0021] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below with reference to the accompanying drawings. The same reference numerals in the drawings denote elements having the same or similar functions. Although various aspects of the embodiments are shown in the drawings, the drawings do not have to be drawn to scale unless otherwise specified.

[0022] The special term "exemplary" herein means "serving as an example, embodiment, or illustration". Any embodiment described as "exemplary" herein does not have to be construed as superior to or better than other embodiments.

[0023] The term "and / or" in this article is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the term "at least one" in this article means any one of multiple or any combination of at least two of multiple. For example, including at least one of A, B, and C can represent including any one or more elements selected from the set composed of A, B, and C.

[0024] In addition, in order to better illustrate the present invention, numerous specific details are given in the following detailed implementation manners. Those skilled in the art should understand that the present invention can also be implemented without some specific details. In some instances, methods, means, elements, and circuits well known to those skilled in the art are not described in detail so as to highlight the gist of the present invention.

[0025] Figure 1 The structural schematic diagram of a gas holdup regulation system based on oil-gas-water multiphase flow according to an embodiment of the present invention is shown, as Figure 1As shown, a gas holdup regulation system based on oil-gas-water multiphase flow includes: a flow supply unit, a mixing unit, an angle simulation unit, a pipe diameter simulation unit, and a total control unit; the total control unit is respectively connected to the flow supply unit, the mixing unit, the angle simulation unit, and the pipe diameter simulation unit; the total control unit is used to control the flow supply unit to output one or several media with a predetermined flow rate and transmit them to the pipe diameter simulation unit, or control to transmit to the pipe diameter simulation unit after passing through the mixing unit and / or the angle simulation unit; the mixing unit is used to mix two-phase or three-phase media entering it, the angle simulation unit is used to make the media output by the flow supply unit or the mixing unit flow through a pipe with a predetermined incident angle and then enter the pipe diameter simulation unit, and the pipe diameter simulation unit is used to make the media entering it output after passing through pipes with different diameters.

[0026] In the present invention, the media include liquid and / or gas; the liquid in the media is: oil and / or water; and / or, the gas in the media is: natural gas.

[0027] In an embodiment of the present invention, during regulation, the total control unit controls the flow supply unit to output one or several media with a predetermined flow rate, such as outputting oil, water, or natural gas for single-phase, outputting such as oil and water, oil and natural gas, or water and natural gas for two-phase, and outputting such as oil, water, and natural gas for three-phase.

[0028] If the output medium is a single-phase medium and there is no need to simulate the incident angle, the total control unit controls to directly transmit the single-phase medium with a predetermined flow rate to the pipe diameter simulation unit. The pipe diameter simulation unit can simulate different pipe diameters, so as to determine the influence of the gas content when the single-phase medium passes through different pipe diameters by measuring the gas holdup in the single-phase medium output by different pipe diameters of the pipe diameter simulation unit. Among them, the pipe diameter simulation unit includes a DN100 variable pipe diameter section 30 with a diameter of 100 mm, a DN80 variable pipe diameter section 29 with a diameter of 80 mm, and a DN50 variable pipe diameter section 28 with a diameter of 50 mm that are arranged in parallel. The inlets of the three pipe sections are connected to the total control unit through a test pipe section 27.

[0029] If it is necessary to simulate the incident angle, the total control unit controls to transmit the single-phase medium to the angle simulation unit. After the single-phase medium flows through a pipe with a predetermined incident angle, it then enters the pipe diameter simulation unit for output, so as to be able to determine the gas holdup of the medium at the predetermined incident angle.

[0030] If the output medium is a two-phase or more medium, you can choose to fully mix the multiple mediums through the mixing unit before output or directly mix them naturally in the pipeline before output. If it is a natural mixture, the general control unit controls the flow supply unit to output the two-phase or more mediums with a predetermined flow rate and then directly transmits it to the pipe diameter simulation unit. If the mixing unit is required to mix, the general control unit controls the predetermined flow rate of the two-phase or more medium output by the flow supply unit to be transmitted to the mixing unit, and controls the mixing unit to start the multiple mediums to be fully mixed. In the absence of incident angle simulation requirements, the general control unit controls the mixed medium output by the mixing unit to be transmitted to the pipe diameter simulation unit; if the incident angle needs to be simulated, the general control unit controls the mixed medium to be transmitted to the angle simulation unit, and the mixed medium flows through the pipeline with a predetermined incident angle, and then enters the pipe diameter simulation unit for output. The mixing efficiency of the medium in the natural state is relatively low. The mixing unit can improve the mixing effect of the medium to meet the requirements of industrial production.

[0031] In the present invention, the flow supply unit includes: a liquid delivery pipeline, a gas delivery pipeline, a data acquisition unit and a flow control unit; the inlets of the liquid delivery pipeline and the gas delivery pipeline are connected to the corresponding medium source, and the outlets are connected to the general control unit; the liquid delivery pipeline and the gas delivery pipeline are respectively provided with corresponding first switch valves, and the first switch valves are connected to the general control unit; the data acquisition unit is respectively connected to the liquid delivery pipeline and the gas delivery pipeline, and the data acquisition unit is used to detect the real-time flow of liquid and / or gas in the liquid delivery pipeline and / or the gas delivery pipeline, and transmit it to the general control unit; the flow control unit is respectively connected to the liquid delivery pipeline and the gas delivery pipeline, and the general control unit is used to adjust the real-time flow of liquid in the liquid delivery pipeline and / or gas in the gas delivery pipeline through the flow control unit.

[0032] In the present invention, the data acquisition unit includes: a liquid flow sensor and a gas flow sensor; the liquid flow sensor for detecting the real-time flow rate of the liquid inside the liquid delivery pipeline is arranged between the switch valve and the outlet; the gas flow sensor for detecting the real-time flow rate of the gas inside the gas delivery pipeline is arranged between the switch valve and the outlet; the liquid flow sensor and the gas flow sensor are connected to the total control unit.

[0033] In the present invention, the flow control unit includes: a liquid flow regulating valve and a gas flow regulating valve; a liquid flow sensor for detecting the real-time flow rate of the liquid inside is arranged between the liquid flow sensor and the outlet on the liquid delivery pipeline; a gas flow sensor for detecting the real-time flow rate of the gas inside is arranged between the gas flow sensor and the outlet on the gas delivery pipeline; the liquid flow sensor and the gas flow sensor are connected to the total control unit.

[0034] In an embodiment of the present invention, the liquid delivery pipeline includes: an oil delivery pipeline 10 and a water delivery pipeline 11, and the gas delivery pipeline includes: a natural gas delivery pipeline 12. One ends of the oil delivery pipeline 10, the water delivery pipeline 11 and the natural gas delivery pipeline 12 are respectively connected to the corresponding oil, water, and natural gas medium sources. The first switch valve includes an oil switch valve 1 arranged on the oil delivery pipeline 10, a water switch valve 4 arranged on the water delivery pipeline 11, and a natural gas switch valve 7 arranged on the natural gas delivery pipeline 12. The liquid flow sensors include an oil flow sensor 2 arranged on the oil delivery pipeline 10 and a water flow sensor 5 arranged on the water delivery pipeline 11; the gas flow sensors include a natural gas flow sensor 8 arranged on the natural gas delivery pipeline 12. The liquid flow regulating valves include an oil flow regulating valve 3 arranged on the oil delivery pipeline 10 and a water flow regulating valve 6 arranged on the water delivery pipeline 11; the gas flow regulating valves include a natural gas flow regulating valve 9 arranged on the natural gas delivery pipeline 12.

[0035] If it is necessary to output one or more media, the total control unit controls the corresponding oil switch valve 1 and / or water switch valve 4 and / or natural gas switch valve 7 to open, and controls the corresponding oil flow sensor 2 and / or water flow sensor 5 to start detecting the real-time flow rate of the liquid in the corresponding oil delivery pipeline 10 or water delivery pipeline 11, and / or controls the natural gas flow sensor 8 to start detecting the real-time flow rate of the gas in the natural gas delivery pipeline 12, and transmits it to the total control unit. The total control unit determines whether the detected real-time flow rate reaches the corresponding predetermined flow rate. If not, the total control unit controls to adjust the opening degrees of the corresponding oil flow regulating valve 3 and / or water flow regulating valve 6 and / or natural gas flow regulating valve 9 to make the real-time flow rate reach the predetermined flow rate. When the amount of the output oil and / or water and / or natural gas reaches the predetermined amount, the total control unit controls the corresponding oil switch valve 1 and / or water switch valve 4 and / or natural gas switch valve 7 to close.

[0036] In the present invention, the angle simulation unit includes: a plurality of incident angle pipelines and an angle control unit; the inlet of the incident angle pipeline is connected to the total control unit, and the outlet is connected to the pipe diameter simulation unit; the angle between the outlet of each incident angle pipeline and the horizontal line at the inlet of the pipe diameter simulation unit is a predetermined incident angle, and the predetermined incident angles corresponding to each incident angle pipeline are different; the angle control unit is connected to the incident angle pipeline, and the angle control unit is used to control the medium to enter the incident angle pipeline corresponding to the predetermined incident angle.

[0037] In the present invention, the angle control unit includes: a second switching valve; a corresponding second switching valve is respectively arranged on each incident angle pipeline, and the second switching valve is connected to the total control unit.

[0038] In an embodiment of the present invention, the plurality of incident angle pipelines include: a 30° incident angle pipeline, a 45° incident angle pipeline, and a 60° incident angle pipeline. The bottom end of each incident angle pipeline is connected to the flow supply unit and the mixing unit through the incident pipeline 31, and the top end is connected to the test section 27 of the pipe diameter simulation unit. The test section 27 is horizontally arranged, and the angles formed between the 30° incident angle pipeline, the 45° incident angle pipeline, and the 60° incident angle pipeline and the test section 27 are 30°, 45°, and 60° respectively.

[0039] The second switching valve includes a 30° incident angle pipe section switching valve 21 arranged on the 30° incident angle pipeline, a 45° incident angle pipe section switching valve 22 arranged on the 45° incident angle pipeline, and a 60° incident angle pipe section switching valve 23 arranged on the 60° incident angle pipeline.

[0040] If it is necessary to simulate the incident angle, the total control unit controls the medium output by the flow supply unit or the mixing unit to be transmitted to the angle simulation unit. At the same time, the 30° incident angle pipe section switching valve 21 or the 45° incident angle pipe section switching valve 22 or the 60° incident angle pipe section switching valve 23 corresponding to the predetermined incident angle to be simulated is controlled to be opened, so that the medium enters the corresponding 30° incident angle pipeline or 45° incident angle pipeline or 60° incident angle pipeline; after the medium flows through the pipeline with a predetermined incident angle, it then enters the pipe diameter simulation unit for output, so that the gas content rate of the medium at the predetermined incident angle can be determined.

[0041] In the present invention, the mixing unit includes: a liquid mixer and a gas-liquid mixer 14; an inlet of the liquid mixer is connected to the overall control unit, an outlet thereof is connected to the gas-liquid mixer 14, and an outlet of the gas-liquid mixer 14 is connected to the overall control unit; the liquid mixer is configured to mix the liquid entering therein, and the gas-liquid mixer 14 is configured to mix the liquid and gas entering therein; inlets and outlets of the liquid mixer and the gas-liquid mixer 14 are respectively connected to the overall control unit.

[0042] In an embodiment of the present invention, if all the multiphase media output by the flow supply unit are liquids, the overall control unit controls to transmit the multiphase media with a predetermined flow rate output to the liquid mixer, and controls the liquid mixer to start to fully mix the multiphase liquid media and then transmit them to the pipe diameter simulation unit or the angle simulation unit. If the multiphase media output by the flow supply unit contain gas, the overall control unit controls to transmit the multiphase gas-liquid media with a predetermined flow rate output to the gas-liquid mixer 14, and controls the gas-liquid mixer 14 to start to fully mix the multiphase gas-liquid media and then transmit them to the pipe diameter simulation unit or the angle simulation unit. Among them, the liquid mixer is: an oil-water mixer 13.

[0043] In the present invention, the overall control unit includes: a first connecting pipeline 16, a single-phase medium switching valve 15, a gas mixing switching valve 18, an incident angle pipe section right switching valve 20, and an incident angle pipe section left switching valve 19; the liquid delivery pipeline is connected to the liquid mixer, and the gas-liquid mixer 14 is connected to the pipe diameter simulation unit through the test switching valve 17; the gas delivery pipeline is connected to the angle simulation unit through the incident angle pipe section right switching valve 20, and the angle simulation unit is connected to the pipe diameter simulation unit; one end of the first connecting pipeline 16 is in pipeline communication between the liquid delivery pipeline and the liquid mixer, the other end of the first connecting pipeline 16 is in pipeline communication between the gas-liquid mixer 14 and the test switching valve 17, and a single-phase medium switching valve 15 is provided on the first connecting pipeline 16; one end of the gas mixing switching valve 18 is in pipeline communication between the liquid mixer and the gas mixer, and the other end of the gas mixing switching valve 18 is in communication with the gas delivery pipeline; one end of the incident angle pipe section left switching valve 19 is in pipeline communication between the gas-liquid mixer 14 and the test switching valve 17, and the other end of the incident angle pipe section left switching valve 19 is in the gas delivery pipeline between the gas mixing switching valve 18 and the incident angle pipe section right switching valve 20.

[0044] In an embodiment of the present invention, the other ends of the oil delivery pipeline 10 and the water delivery pipeline 11 are connected to the oil-water mixer 13, and the gas-liquid mixer 14 is connected to the test pipe section 27 through the test switching valve 17. The other end of the natural gas delivery pipeline 12 is connected to the incident pipeline 31 through the incident angle pipe section right switching valve 20.

[0045] If the medium to be output is a single-phase liquid medium and there is no requirement for incident angle simulation, control the opening of the oil switch valve 1 or the water switch valve 4, the single-phase medium switch valve 15, and the test switch valve 17, and control the closing of the gas mixing switch valve 18, the left switch valve 19 of the incident angle pipe section, and the right switch valve 20 of the incident angle pipe section; oil or water enters the first connecting pipe 16 through the corresponding oil delivery pipe 10 or water delivery pipe 11, and after passing through the single-phase medium switch valve 15 and the test switch valve 17, enters the test pipe section 27 and finally enters the variable diameter pipe section. If the medium to be output is a single-phase gas medium, then control the closing of the oil switch valve 1, the water switch valve 4, the single-phase medium switch valve 15, the gas mixing switch valve 18, and the right switch valve 20 of the incident angle pipe section, and control the opening of the natural gas switch valve 7, the left switch valve 19 of the incident angle pipe section, and the test switch valve 17; natural gas enters the test pipe section 27 from the natural gas delivery pipe 12 through the left switch valve 19 of the incident angle pipe section and the test switch valve 17, and finally enters the variable diameter pipe section.

[0046] If the medium to be output is a two-phase liquid medium and there is no incident angle simulation and no mixing is required, control the opening of the oil switch valve 1 and the water switch valve 4, the single-phase medium switch valve 15, and the test switch valve 17, and control the closing of the gas mixing switch valve 18, the left switch valve 19 of the incident angle pipe section, and the right switch valve 20 of the incident angle pipe section; oil and water respectively enter the first connecting pipe 16 through the oil delivery pipe 10 and the water delivery pipe 11, and then pass through the single-phase medium switch valve 15 and the test switch valve 17 to enter the test pipe section 27. If the medium to be output contains gas and liquid, then control the opening of the oil switch valve 1 and / or the water switch valve 4, the natural gas switch valve 7, the single-phase medium switch valve 15, the test switch valve 17, and the left switch valve 19 of the incident angle pipe section, and control the closing of the gas mixing switch valve 18 and the right switch valve 20 of the incident angle pipe section; oil and / or water enter the first connecting pipe 16, pass through the single-phase medium switch valve 15 to enter the test pipe section 27, and natural gas enters the test pipe section 27 through the left switch valve 19 of the incident angle pipe section and the test switch valve 17, and finally enters the variable diameter pipe section.

[0047] If the medium to be output is a two-phase liquid medium, in the case of no incident angle simulation but mixing is required, control the oil switch valve 1, water switch valve 4, and test switch valve 17 to open, and control the single-phase medium switch valve 15, gas mixing switch valve 18, left incident angle pipe section switch valve 19, and right incident angle pipe section switch valve 20 to close; oil and water enter the oil-water mixer 13 through the oil delivery pipeline 10 and water delivery pipeline 11 respectively, control the oil-water mixer 13 to start, mix the oil and water entering it, and then flow through the gas-liquid mixer 14 and test switch valve 17 and be transmitted to the test pipe section 27; among them, the mixed liquid can choose to pass through the gas-liquid mixer 14 or bypass it. Specifically, by controlling the gas mixing switch valve 18 and the left incident angle pipe section switch valve 19 to open, the liquid mixed by the oil-water mixer 13 can directly enter the test pipe section 27 through the two of them. If the medium to be output contains gas and liquid, then control the oil switch valve 1 and / or water switch valve 4, natural gas switch valve 7, gas mixing switch valve 18, and test switch valve 17 to open, and control the single-phase medium switch valve 15, left incident angle pipe section switch valve 19, and right incident angle pipe section switch valve 20 to close; oil and / or water enter the gas-liquid mixer 14 through the oil-water mixer 13, and at the same time natural gas enters the gas-liquid mixer 14 from the natural gas delivery pipeline 12 through the gas mixing switch valve 18; control the gas-liquid mixer 14 to start, mix the gas and liquid entering it, and then transport it through the test switch valve 17 into the test pipe section 27, and finally enter the variable diameter pipe section.

[0048] If the medium to be output is a single-phase liquid medium, in the case of incident angle simulation required, control the oil switch valve 1 or water switch valve 4, single-phase medium switch valve 15, left incident angle pipe section switch valve 19, and right incident angle pipe section switch valve 20 to open, and control the gas mixing switch valve 18 and test switch valve 17 to close; oil or water enters the first connecting pipeline 16 through the corresponding oil delivery pipeline 10 or water delivery pipeline 11, and after passing through the single-phase medium switch valve 15, left incident angle pipe section switch valve 19, and right incident angle pipe section switch valve 20, enters the incident pipeline 31; after entering the incident pipeline 31, control the 30° incident angle pipe section switch valve 21 or 45° incident angle pipe section switch valve 22 or 60° incident angle pipe section switch valve 23 corresponding to the predetermined incident angle to open, and after the oil or water passes through the corresponding 30° incident angle pipeline 24 or 45° incident angle pipeline 25 or 60° incident angle pipeline 26, it enters the test pipe section 27, and finally enters the variable diameter pipe section. If the medium to be output is a single-phase gas medium, then control the oil switch valve 1, water switch valve 4, single-phase medium switch valve 15, gas mixing switch valve 18, test switch valve 17, and left incident angle pipe section switch valve 19 to close, and control the natural gas switch valve 7 and right incident angle pipe section switch valve 20 to open; natural gas enters the incident pipeline 31 from the natural gas delivery pipeline 12 through the right incident angle pipe section switch valve 20, and control the corresponding incident angle pipe section switch valve to open so that the gas enters the corresponding incident angle pipeline, and finally enters the test pipe section 27.

[0049] If the medium to be output is a two-phase liquid medium, in the case where the incident angle simulation is required but mixing is not required, control the oil switch valve 1, the water switch valve 4, the single-phase medium switch valve 15, the left switch valve 19 of the incident angle pipe section, and the right switch valve 20 of the incident angle pipe section to open, and control the gas mixing switch valve 18 and the test switch valve 17 to close; oil and water enter the first connecting pipe 16 through the oil delivery pipeline 10 and the water delivery pipeline 11 respectively, and then enter the incident pipeline 31 after passing through the single-phase medium switch valve 15, the left switch valve 19 of the incident angle pipe section, and the right switch valve 20 of the incident angle pipe section. If the medium to be output contains gas and liquid, then control the oil switch valve 1 and / or the water switch valve 4, the natural gas switch valve 7, the single-phase medium switch valve 15, the right switch valve 20 of the incident angle pipe section, and the left switch valve 19 of the incident angle pipe section to open, and control the gas mixing switch valve 18 and the test switch valve 17 to close; oil and / or water enter the first connecting pipe 16, pass through the single-phase medium switch valve 15, the right switch valve 20 of the incident angle pipe section, and the left switch valve 19 of the incident angle pipe section to enter the incident pipeline 31, and natural gas enters the incident pipeline 31 through the right switch valve 20 of the incident angle pipe section. After controlling the corresponding incident angle pipe section switch valve to open to allow the liquid and gas to enter the corresponding incident angle pipeline, they finally enter the test pipe section 27.

[0050] If the medium to be output is a two-phase liquid medium, in the case where incident angle simulation and mixing are required, control the oil switch valve 1, the water switch valve 4, the left switch valve 19 of the incident angle pipe section, and the right switch valve 20 of the incident angle pipe section to open, and control the single-phase medium switch valve 15, the test switch valve 17, and the gas-liquid mixing switch valve 18 to close; oil and water enter the oil-water mixer 13 through the oil delivery pipeline 10 and the water delivery pipeline 11 respectively. Control the oil-water mixer 13 to start, fully mix the oil and water entering its interior, and then transmit it through the gas-liquid mixer 14, the left switch valve 19 of the incident angle pipe section, and the right switch valve 20 of the incident angle pipe section to the incident pipeline 31. If the medium to be output contains gas and liquid, then control the oil switch valve 1 and / or the water switch valve 4, the natural gas switch valve 7, the gas-liquid mixing switch valve 18, the left switch valve 19 of the incident angle pipe section, and the right switch valve 20 of the incident angle pipe section to open, and control the single-phase medium switch valve 15 and the test switch valve 17 to close; after the oil and / or water enters the oil-water mixer 13, if it contains more than two-phase liquids, then control the oil-water mixer 13 to start, fully mix the oil and water entering its interior, and convey the mixed liquid into the gas-liquid mixer 14. At the same time, natural gas enters the gas-liquid mixer 14 through the natural gas delivery pipeline 12 via the gas-liquid mixing switch valve 18. Control the gas-liquid mixer 14 to start, fully mix the mixed liquid and natural gas entering its interior, and convey the mixed gas-liquid mixture through the left switch valve 19 of the incident angle pipe section and the right switch valve 20 of the incident angle pipe section into the incident pipeline 31; after controlling the corresponding incident angle pipe section switch valve to open to allow the liquid and gas to enter the corresponding incident angle pipeline, finally enter the test pipe section 27.

[0051] The present invention also provides a method for regulating the gas holdup based on oil-gas-water multiphase flow, including: obtaining the parameters required for the simulation environment when measuring the test gas holdup, including the type of medium, the corresponding predetermined flow rate of each medium, and when there is an incident angle in the simulation environment, its corresponding predetermined incident angle value; the total control unit controls the flow supply unit to start and output the medium of the obtained predetermined flow rate and type. If the type of medium is one, the total control unit controls to transmit the medium to the pipe diameter simulation unit; if the type of medium is two or more, the total control unit controls to transmit the medium output by the flow supply unit to the mixing unit, and the mixing unit mixes two or more media and then transmits it to the pipe diameter simulation unit; if there is an incident angle in the simulation environment, the total control unit controls to transmit the medium output by the flow supply unit or the mixed medium output by the mixing unit to the angle simulation unit, and the angle simulation unit makes the medium flow through the pipeline corresponding to the predetermined incident angle value and then inputs it into the pipe diameter simulation unit.

[0052] In the embodiment of the present invention, when there is no need for mixing and no need to simulate the incident angle, if the output medium type is single-phase oil, the oil switch valve 1 is controlled to open, the water switch valve 4 and the gas switch valve are closed, and the oil is output through the oil delivery pipeline 10; the real-time flow rate of the oil in the pipeline is detected by the oil flow sensor 2, and the real-time flow rate in the pipeline is adjusted to be equal to the predetermined flow rate by the oil flow regulating valve 3. The total control unit controls the single-phase medium switch valve 15 and the test switch valve 17 to open, and controls the gas mixing switch valve 18, the left switch valve 19 of the incident angle pipe section, the right switch valve 20 of the incident angle pipe section, and the switch valves of each angle incident angle pipe section to close. After the oil enters the first connecting pipeline 16, it enters the test pipeline after passing through the single-phase medium switch valve 15 and the test switch valve 17, and finally enters the DN100 variable diameter pipe section 30, the DN80 variable diameter pipe section 29, and the DN50 variable diameter pipe section 28 for output respectively.

[0053] When mixing is required but the incident angle does not need to be simulated, if the output medium types are oil and water, the control method is the same as the above single-phase control process. If mixing is required, the oil switch valve 1, the water switch valve 4, and the test switch valve 17 are controlled to open, and the gas switch valve, the single-phase medium switch valve 15, the gas mixing switch valve 18, the left switch valve 19 of the incident angle pipe section, and the right switch valve 20 of the incident angle pipe section are closed; a predetermined flow rate of oil and water is transported into the started oil-water mixer 13 through the oil delivery pipeline 10 and the water delivery pipeline 11 for sufficient mixing, and the mixed oil-water mixture is transported to the DN100 variable diameter pipe section 30, the DN80 variable diameter pipe section 29, and the DN50 variable diameter pipe section 28 through the test switch valve 17 for output. If the output medium also includes natural gas, the gas mixing switch valve 18 also needs to be controlled to open to control the output of a predetermined flow rate of natural gas; at the same time, the gas-liquid mixer 14 is controlled to start, so that the oil-water mixture output by the oil-water mixer 13 and the natural gas transported through the natural gas pipeline 12 enter the gas-liquid mixer 14 through the gas mixing switch valve 18 for sufficient mixing, and the mixed oil-water-natural gas mixture enters the DN100 variable diameter pipe section 30, the DN80 variable diameter pipe section 29, and the DN50 variable diameter pipe section 28 through the test switch valve 17 for output.

[0054] When mixing is not required but the incident angle needs to be simulated, if the types of media to be output are oil and water, and the simulated incident angle is 30°, then control the oil switch valve 1 and / or the water switch valve 4, the single-phase medium switch valve 15, the left switch valve 19 of the incident angle pipe section, the right switch valve 20 of the incident angle pipe section, and the 30° incident angle pipe section switch valve 21 to open, and control the gas switch valve, the gas mixing switch valve 18, the test switch valve 17, the 45° incident angle pipe section switch valve 22, and the 60° incident angle pipe section switch valve 23 to close; through the oil delivery pipeline 10 and the water delivery pipeline 11, deliver the predetermined flow rates of oil and water to the 30° incident angle pipeline 24 through the first connection pipeline 16, the single-phase medium switch valve 15, the left switch valve 19 of the incident angle pipe section, the right switch valve 20 of the incident angle pipe section, and the 30° incident angle pipe section switch valve 21, and then enter the DN100 variable diameter pipe section 30, the DN80 variable diameter pipe section 29, and the DN50 variable diameter pipe section 28 through the test pipe section 27 and then output. If the media to be output also includes natural gas, then it is also necessary to control the natural gas switch valve 7 to open; control the output of the predetermined flow rate of natural gas, and after passing through the right switch valve 20 of the incident angle pipe section, the 30° incident angle pipe section switch valve 21, and the test pipe section 27, enter the DN100 variable diameter pipe section 30, the DN80 variable diameter pipe section 29, and the DN50 variable diameter pipe section 28 and then output.

[0055] When mixing and simulating the incident angle need to be carried out simultaneously, if the types of media to be output are oil and water, and the simulated incident angle is 45°, then control the oil switch valve 1, the water switch valve 4, the left switch valve 19 of the incident angle pipe section, the right switch valve 20 of the incident angle pipe section, and the 45° incident angle pipe section switch valve 22 to open, and control the gas switch valve, the single-phase medium switch valve 15, the gas mixing switch valve 18, the test switch valve 17, the 30° incident angle pipe section switch valve 21, and the 60° incident angle pipe section switch valve 23 to close; through the oil delivery pipeline 10 and the water delivery pipeline 11, deliver the predetermined flow rates of oil and water into the started oil-water mixer 13 for mixing, and then pass through the gas-liquid mixer 14, the left switch valve 19 of the incident angle pipe section, the right switch valve 20 of the incident angle pipe section, and the 45° incident angle pipe section switch valve 22 to enter the 45° incident angle pipeline 25, and finally pass through the test pipe section 27 and be delivered to the DN100 variable diameter pipe section 30, the DN80 variable diameter pipe section 29, and the DN50 variable diameter pipe section 28 and then output. If the media to be output also includes natural gas, then it is also necessary to control the natural gas switch valve 7 and the gas mixing switch valve 18 to open; control the output of the predetermined flow rate of natural gas, pass through the gas mixing switch valve 18 and enter the gas-liquid mixer 14, and through the started gas-liquid mixer 14, mix the natural gas and the mixed oil-water mixture again, and then pass through the left switch valve 19 of the incident angle pipe section, the right switch valve 20 of the incident angle pipe section, and the 45° incident angle pipe section switch valve 22 to enter the 45° incident angle pipeline 25, and finally pass through the test pipe section 27 and be delivered to the DN100 variable diameter pipe section 30, the DN80 variable diameter pipe section 29, and the DN50 variable diameter pipe section 28 and then output.

[0056] It can be understood that, without violating the principle logic, the above-mentioned various embodiments mentioned in the present invention can be combined with each other to form a combined embodiment. Due to space limitations, the present invention will not elaborate further.

[0057] By setting up a flow supply unit, the present invention can stably provide the flow rates of different single-phase or multi-phase (gas, oil, water) media, and adjust the flow rate through a flow regulating valve to provide the necessary supply media for the subsequent mixing unit. By setting up a mixing unit and arranging a static mixer between the oil-water outflow pipe section and the gas outflow pipe section, the mixing of different single-phase media is achieved. Such a layout can not only regulate the gas holdup under different media conditions, but also help to deeply understand the characteristics of the mixing of different single-phase media and the influence of these characteristics on the multiphase flow pattern. By setting up an angle simulation unit, different gas incident angles such as 30°, 45°, 60° can be adjusted to verify the influence of different incident angles on the cross-sectional gas holdup. By setting up a pipe diameter simulation unit, different pipe diameters (DN50, DN80, DN100) can be simulated to regulate the gas holdup at different flow velocities under the same flow rate condition, and provide basic conditions for deeply exploring the influence of these factors on the multiphase flow pattern.

[0058] The flow supply unit that provides one-phase or multi-phase media, the mixed flow generated by the mixing unit, the variable incident angle function of the angle simulation unit, and the variable pipe diameter function of the pipe diameter simulation unit form a parallel relationship. These functions can be used alone or in combination of two or more. For the complex environment of the oil and gas field, diversified gas holdup regulation strategies are provided. This design enhances the flexibility and adaptability of the device, enabling it to better meet the professional requirements under different working conditions.

[0059] The present invention can accurately regulate the gas holdup under different conditions required in the industrial field, and precisely complete the regulation of the gas holdup under complex conditions such as multiphase flow mixing, different incident angles, and flow velocities. It not only has important significance in theoretical research, but also has broad application prospects in engineering practice.

[0060] Those skilled in the art can understand that in the above method of the specific implementation manner, the writing order of each step does not mean a strict execution order that constitutes any limitation to the implementation process. The specific execution order of each step should be determined according to its function and possible internal logic.

[0061] The embodiments of the present invention have been described above. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to technologies in the market, or to enable other ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A gas holdup regulation system based on oil-gas-water multiphase flow, characterized in that, Comprising: A flow supply unit, a mixing unit, an angle simulation unit, a pipe diameter simulation unit, and a total control unit; The total control unit is respectively connected to the flow supply unit, the mixing unit, the angle simulation unit, and the pipe diameter simulation unit; The total control unit is used to control the flow supply unit to output one or several media with a predetermined flow rate and transmit them to the pipe diameter simulation unit, or to control the transmission to the pipe diameter simulation unit after passing through the mixing unit and / or the angle simulation unit; The mixing unit is used to mix two-phase or three-phase media entering it, the angle simulation unit is used to make the media output by the flow supply unit or the mixing unit flow through a pipeline with a predetermined incident angle and then enter the pipe diameter simulation unit, and the pipe diameter simulation unit is used to output the media entering it after passing through pipelines with different pipe diameters.

2. The gas holdup regulation system for oil-gas-water multiphase flow according to claim 1, wherein The flow supply unit includes: a liquid delivery pipeline, a gas delivery pipeline, a data acquisition unit, and a flow control unit; The inlets of the liquid delivery pipeline and the gas delivery pipeline are connected to corresponding media sources, and the outlets are connected to the total control unit; Corresponding first switch valves are respectively arranged on the liquid delivery pipeline and the gas delivery pipeline, and the first switch valves are connected to the total control unit; The data acquisition unit is respectively connected to the liquid delivery pipeline and the gas delivery pipeline, and the data acquisition unit is used to detect the real-time flow rate of the liquid and / or gas in the liquid delivery pipeline and / or the gas delivery pipeline and transmit it to the total control unit; The flow control unit is respectively connected to the liquid delivery pipeline and the gas delivery pipeline, and the total control unit is used to adjust the real-time flow rate of the liquid in the liquid delivery pipeline and / or the gas in the gas delivery pipeline through the flow control unit.

3. The gas holdup regulation system for oil-gas-water multiphase flow according to claim 2, wherein The data acquisition unit includes: a liquid flow sensor and a gas flow sensor; A liquid flow sensor for detecting the real-time flow rate of the liquid inside it is arranged between the switch valve and the outlet on the liquid delivery pipeline; A gas flow sensor for detecting the real-time flow rate of the gas inside it is arranged between the switch valve and the outlet on the gas delivery pipeline; The liquid flow sensor and the gas flow sensor are connected to the total control unit.

4. The gas holdup regulation system for oil-gas-water multiphase flow according to claim 3, characterized in that, The flow control unit includes: a liquid flow regulating valve and a gas flow regulating valve; A liquid flow sensor for detecting the real-time flow rate of the liquid inside it is arranged between the liquid flow sensor and the outlet on the liquid delivery pipeline; A gas flow sensor for detecting the real-time flow rate of the gas inside it is arranged between the gas flow sensor and the outlet on the gas delivery pipeline; The liquid flow sensor and the gas flow sensor are connected to the total control unit.

5. The gas holdup regulation system for oil-gas-water multiphase flow according to claim 1, wherein The angle simulation unit includes: several incident angle pipelines and an angle control unit; The inlets of the incident angle pipelines are connected to the total control unit, and the outlets are connected to the pipe diameter simulation unit; The included angle between the outlet of each incident angle pipeline and the horizontal line at the inlet of the pipe diameter simulation unit is a predetermined incident angle, and the corresponding predetermined incident angles of each incident angle pipeline are different; The angle control unit is connected to the incident angle pipeline, and the angle control unit is used to control the medium to enter the incident angle pipeline corresponding to a predetermined incident angle.

6. The gas holdup regulation system for oil-gas-water multiphase flow according to claim 5, characterized in that, The angle control unit includes: a second switching valve; Each of the incident angle pipelines is respectively provided with a corresponding second switching valve, and the second switching valve is connected to the total control unit.

7. The gas holdup regulation system for oil-gas-water multiphase flow according to any one of claims 2-6, characterized in that The mixing unit includes: a liquid mixer and a gas-liquid mixer (14); The inlet of the liquid mixer is connected to the total control unit, the outlet is connected to the gas-liquid mixer (14), and the outlet of the gas-liquid mixer (14) is connected to the total control unit; The liquid mixer is used to mix the liquid entering its interior, and the gas-liquid mixer (14) is used to mix the liquid and gas entering its interior; The inlets and outlets of the liquid mixer and the gas-liquid mixer (14) are respectively connected to the total control unit.

8. The gas holdup regulation system for oil-gas-water multiphase flow according to claim 7, characterized in that, The total control unit includes: a first connecting pipeline (16), a single-phase medium switching valve (15), a gas mixing switching valve (18), a right switching valve for the incident angle pipe section (20), a left switching valve for the incident angle pipe section (19), and a test switching valve (17); The liquid delivery pipeline is connected to the liquid mixer, and the gas-liquid mixer (14) is connected to the pipe diameter simulation unit through the test switching valve (17); The gas delivery pipeline is connected to the angle simulation unit through the right switching valve for the incident angle pipe section (20), and the angle simulation unit is connected to the pipe diameter simulation unit; One end of the first connecting pipeline (16) is in pipeline communication between the liquid delivery pipeline and the liquid mixer, the other end of the first connecting pipeline (16) is in pipeline communication between the gas-liquid mixer (14) and the test switching valve (17), and a single-phase medium switching valve (15) is provided on the first connecting pipeline (16); One end of the gas mixing switching valve (18) is in pipeline communication between the liquid mixer and the gas mixer, and the other end of the gas mixing switching valve (18) is in communication with the gas delivery pipeline; One end of the left switching valve for the incident angle pipe section (19) is in pipeline communication between the gas-liquid mixer (14) and the test switching valve (17), and the other end of the left switching valve for the incident angle pipe section (19) is in pipeline communication with the gas delivery pipeline between the gas mixing switching valve (18) and the right switching valve for the incident angle pipe section (20).

9. The oil-gas-water multiphase flow gas holdup regulation system according to any one of claims 1-6, 8, characterized in that: The medium includes liquid and / or gas; The liquid in the medium is: oil and / or water; And / or, the gas in the medium is: natural gas.

10. A gas holdup regulation method based on oil-gas-water multiphase flow, characterized in that, Includes: Obtain the parameters required for the simulation environment when measuring the test gas holdup, including the medium type, the predetermined flow rate corresponding to each medium, and when there is an incident angle in the simulation environment, its corresponding predetermined incident angle value; The total control unit controls the flow supply unit to start, outputs the medium of the obtained predetermined flow rate and type, and if the medium type is one, the total control unit controls to transmit the medium to the pipe diameter simulation unit; If there are two or more types of media, the total control unit controls the transmission of the media output by the flow supply unit to the mixing unit, and after mixing two or more types of media through the mixing unit, transmits them to the pipe diameter simulation unit; If there is an incident angle in the simulation environment, the total control unit controls the transmission of the media output by the flow supply unit or the mixed media output by the mixing unit to the angle simulation unit, and the angle simulation unit inputs the media into the pipe diameter simulation unit after the media flows through the pipeline corresponding to the predetermined incident angle value.

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