Ultrasonic Measurement Device and Method for Oil-Water Two-Phase Flow Based on In-Pipe Phase Separation

Abstract

The present invention discloses an ultrasonic measurement device for oil-water two-phase flow based on in-pipe phase separation, which includes a measurement pipeline through which the oil-water two-phase flow passes; a phase separation assembly arranged on the measurement pipeline; and an ultrasonic measurement assembly arranged on the measurement pipeline, including an ultrasonic signal transmitter-receiver and at least one ultrasonic probe electrically connected to the ultrasonic signal transmitter-receiver, wherein the ultrasonic probe is arranged on the measurement pipeline. The present invention also provides an ultrasonic measurement method based on the above ultrasonic measurement device. The present invention can achieve synchronous measurement of multiple parameters of oil-water two-phase flow.

Description

Technical Field

[0001] The present invention relates to the technical field of fluid measurement, and particularly to an ultrasonic measurement device and method for oil-water two-phase flow based on in-pipe phase separation. Background Art

[0002] The oil reserves and production capacity have always been the focus of the world's energy development. Due to long-term water injection for oil production, 80% of the oilfields in China have entered the high water cut period, which brings great difficulties to the measurement in the middle and late stages of high water cut oilfields. Therefore, the research on the online measurement method of oil-water two-phase flow parameters in high water cut is of great significance for crude oil production, oil well output, reservoir management, etc.

[0003] The main methods for measuring phase holdup and oil-water flow rate include the large tank oil measurement method, the artificial sampling measurement method, and the online measurement method. Among them, the first two methods have large human factors and low efficiency, and cannot achieve real-time measurement. At present, many researchers have studied the online measurement method of oil-water two-phase flow. Most traditional online measurement methods use single-phase flow meters or a combination of multiple flow meters for measurement, such as the method of combining an oval gear flow meter and a Venturi flow meter. However, this method is generally affected by the measurement range or the type of flow pattern, and the measurement accuracy is not high. The currently widely used online measurement methods include the electrical method, the differential pressure method, the ultrasonic method, etc. The electrical method is divided into the conductivity method and the capacitance method. The capacitance method cannot be used to measure two-phase flow with a conductive continuous phase due to the short-circuit effect. Although the conductivity method is applicable to two-phase flow with a conductive continuous phase, it still cannot guarantee the measurement accuracy in the case of high water cut. The differential pressure method can be used to measure low-speed high water cut oil-water two-phase flow, but the friction coefficient strongly depends on the flow pattern. The ultrasonic method has the advantages of fast response, simple structure, high permeability, no radiation, etc., and is not affected by conductivity. It can detect the flow parameters of two-phase flow by analyzing the ultrasonic signals after diffraction, reflection, refraction or transmission of ultrasonic waves. However, the ultrasonic method is sensitive to the size and concentration changes of dispersed oil droplets, and there is a problem of non-linear response. Therefore, the measurement range and accuracy of the ultrasonic method often cannot be guaranteed.

[0004] Therefore, the present invention is committed to developing an ultrasonic measurement device and method for oil-water two-phase flow based on in-pipe phase separation. By combining in-pipe phase separation and ultrasonic measurement, it can effectively solve the influence of different phase holdups, the size and position of discrete oil droplets, etc. on ultrasonic measurement, and realize the synchronous measurement of multiple parameters of oil-water two-phase flow. Summary of the Invention

[0005] In view of the above-mentioned defects of the prior art, the present invention provides an ultrasonic measurement device and method for oil-water two-phase flow based on in-pipe phase separation. The device mainly includes a phase separation component and an ultrasonic measurement component. The phase separation component consists of a multi-stage cyclone structure and is respectively installed upstream of the measurement pipeline and downstream of the ultrasonic measurement component. The ultrasonic measurement component consists of an ultrasonic probe and an ultrasonic transceiver. The ultrasonic probe is fixed on the same side or both sides of the axial direction of the measurement pipeline. By combining in-pipe phase separation with ultrasonic measurement, different inlet flow patterns are converted into a flow pattern similar to "oil-water annular flow" through in-pipe phase separation, and all the originally dispersed oil droplets are gathered in the center of the pipeline, which can effectively solve the interference problem of dispersed oil droplets in high-water-cut oil-water two-phase flow on ultrasonic measurement. The measurement method is based on in-pipe phase separation and combines the ultrasonic attenuation method and the ultrasonic Doppler method to measure the fluid after in-pipe phase separation of oil-water two-phase flow, and can realize synchronous measurement of multiple parameters such as phase holdup, mixing velocity, flow velocity distribution and flow rate. It mainly includes the following steps: First, combine in-pipe phase separation with the ultrasonic attenuation method to realize the measurement of the sectional holdup of separated phases in oil-water two-phase flow; Second, combine in-pipe phase separation with the continuous-wave ultrasonic Doppler method to realize the measurement of the mixing velocity of oil-water two-phase flow; Third, combine in-pipe phase separation with the pulsed-wave ultrasonic Doppler method to realize the measurement of the flow velocity distribution of oil-water two-phase flow; Fourth, based on the parameter information calculated above, the separated-phase volume flow rate and total volume flow rate of oil-water two-phase flow can be further calculated.

[0006] To achieve the above object, the present invention provides an ultrasonic measurement device for oil-water two-phase flow based on in-pipe phase separation, including:

[0007] A measurement pipeline through which the oil-water two-phase flow flows;

[0008] A phase separation component arranged on the measurement pipeline;

[0009] An ultrasonic measurement component arranged on the measurement pipeline;

[0010] Wherein, the phase separation component includes at least one stage of cyclone structure;

[0011] The ultrasonic measurement component includes an ultrasonic signal transceiver, and at least one ultrasonic probe electrically connected to the ultrasonic signal transceiver, wherein the ultrasonic probe is arranged on the measurement pipeline.

[0012] Further, the at least one stage of cyclone structure includes a vane-type cyclone, and the vane-type cyclone is located upstream of the ultrasonic measurement component; or

[0013] The at least one stage of cyclone structure includes an orifice plate and a vane-type cyclone, and the orifice plate and the vane-type cyclone are sequentially arranged in series upstream of the ultrasonic measurement component;

[0014] The at least one - stage swirl structure includes an orifice plate and two vane - type cyclones. The orifice plate and the two vane - type cyclones are arranged in series upstream of the ultrasonic measurement assembly in sequence, or the orifice plate and one of the vane - type cyclones are arranged in series upstream of the ultrasonic measurement assembly in sequence, and the other vane - type cyclone is arranged downstream of the ultrasonic measurement assembly.

[0015] Further, the structure of the vane - type cyclone is selected from any one of the following five structures:

[0016] Structure 1: The vane - type cyclone is composed of four swirl vanes and a hub unit. The shape of each swirl vane is semi - elliptical. The four swirl vanes are evenly arranged circumferentially. The vane height is the same as the inner diameter of the measurement pipeline. The vane thickness is 1 mm and it is closely attached to the inner wall of the pipeline. One end of the hub unit is hemispherical and the other end is conical. The height is 1.5 times the vane height and it is located at the center of the vane - type cyclone. The normal velocity of the vane surface makes an angle of 45° with the axis of the hub unit.

[0017] Structure 2: The vane - type cyclone is composed of four swirl vanes and a hub unit. The four swirl vanes are evenly arranged circumferentially. The shape of each swirl vane is spiral. The vane height is 1.5 times the inner diameter of the measurement pipeline. The vane thickness is 1 mm and it is closely attached to the inner wall of the pipeline. One end of the hub unit is hemispherical and the other end is conical. The height is 1.5 times the vane height and it is located at the center of the vane - type cyclone. The normal velocity of the vane surface makes an angle of 45° with the axis of the hub unit.

[0018] Structure 3: The vane - type cyclone is composed of four swirl vanes and a hub unit. The shape of each swirl vane is spiral. The four swirl vanes are evenly arranged circumferentially. The vane height is 1.5 times the inner diameter of the measurement pipeline. The vane thickness is 1 mm and it is closely attached to the inner wall of the pipeline. One end of the hub unit is hemispherical and the other end is conical. The height is 1.5 times the vane height and it is located at the center of the vane - type cyclone. The normal velocity of the vane surface gradually changes from 90° to 45° with the axis of the hub unit.

[0019] Structure 4: The vane - type cyclone is composed of four swirl vanes. The shape of each swirl vane is semi - elliptical. The four swirl vanes are evenly arranged circumferentially. The vane height is the same as the inner diameter of the measurement pipeline. The vane thickness is 1 mm and it is closely attached to the inner wall of the pipeline. The normal velocity of the vane surface makes an angle of 45° with the axis of the vane - type cyclone.

[0020] Structure Five: The vane type cyclone is composed of four cyclone vanes. Each cyclone vane is in the shape of an airfoil. The four cyclone vanes are evenly arranged circumferentially. The vane height is 2.5 times the inner diameter of the measurement pipeline, the vane thickness is 1 mm, and it is closely attached to the inner wall of the pipeline; at the 1 / 2 of the vane height, the normal velocity of the vane surface gradually changes from 90° to 30° with the axis of the vane type cyclone.

[0021] Furthermore, among them, the ultrasonic probe is selected from any one of the following five arrangement methods:

[0022] The first arrangement method: The ultrasonic probe includes a set of one transmitting and one receiving single crystal probes arranged on the opposite sides of the measurement pipeline axially.

[0023] The second arrangement method: The ultrasonic probe includes a set of one transmitting and one receiving wedge probes arranged closely on the same side of the measurement pipeline axially and located downstream of the measurement pipeline.

[0024] The third arrangement method: The ultrasonic probe includes a single self-transmitting and self-receiving wedge probe arranged on one side of the measurement pipeline axially and located downstream of the measurement pipeline.

[0025] The fourth arrangement method: The ultrasonic probe includes a set of one transmitting and one receiving single crystal probes arranged on the opposite sides of the measurement pipeline axially and a set of one transmitting and one receiving wedge probes arranged closely on the same side of the measurement pipeline axially and located downstream of the pipeline.

[0026] The fifth arrangement method: The ultrasonic probe includes a set of one transmitting and one receiving single crystal probes arranged on the opposite sides of the measurement pipeline axially and a single self-transmitting and self-receiving wedge probe arranged on one side of the measurement pipeline axially and located downstream of the measurement pipeline.

[0027] The present invention also provides an ultrasonic measurement method using the ultrasonic measurement device for oil-water two-phase flow based on in-pipe phase separation as described above, including:

[0028] Step 1: Perform in-pipe phase separation on the oil-water two-phase flow flowing through the measurement pipeline;

[0029] Step 2: Use the first ultrasonic probe arranged on the measurement pipeline to transmit and receive ultrasonic signals. By extracting the amplitudes V t and V r of the ultrasonic signals at the transmitting end and the receiving end, and combining with the distance l between the transmitting end and the receiving end to obtain the ultrasonic attenuation coefficient K; according to the specific relationship K = F(α o ) between the ultrasonic attenuation coefficient K and the oil phase cross-sectional holdup α o the oil phase cross-sectional holdup α o can be obtained, and further calculate the water phase cross-sectional holdup α w, the oil-water separated cross-sectional area A is calculated from the cross-sectional area A of the pipeline o and A w ; the first ultrasonic probe includes a set of single-crystal probes, one for transmitting and one for receiving, arranged on the axial opposite sides of the measurement pipeline;

[0030] Step 3: Use the second ultrasonic probe arranged on the measurement pipeline to transmit and receive ultrasonic signals. By extracting the amplitudes V of the ultrasonic signals at the transmitting end and the receiving end t and V r , combined with the distance between the transmitting and receiving ends to obtain the ultrasonic attenuation coefficient K; according to the specific relationship between the ultrasonic attenuation coefficient K and the oil-phase cross-sectional holdup α o , the oil-phase cross-sectional holdup α can be obtained o , and further calculate the water-phase cross-sectional holdup α w , and the oil-water separated cross-sectional area A is calculated from the cross-sectional area A of the pipeline o and A w ; the second ultrasonic probe includes a set of one-transmitting and one-receiving wedge probes arranged on the same axial side of the measurement pipeline or a single self-transmitting and self-receiving wedge probe arranged on one axial side of the measurement pipeline;

[0031] Step 4: Use the third ultrasonic probe arranged on the measurement pipeline to transmit and receive ultrasonic signals, and perform spectral analysis on the ultrasonic signals at the receiving end to obtain the average Doppler frequency shift Combined with the mixed sound velocity c of the oil-water two-phase m , to obtain the mixed velocity u of the oil-water two-phase m ; combined with the oil-water separated cross-sectional area and cross-sectional holdup described in Step 2 or Step 3, the measurement of the total volume flow rate and the separated-phase volume flow rate of the two-phase flow is realized; the third ultrasonic probe includes a set of one-transmitting and one-receiving wedge probes arranged on the same axial side of the measurement pipeline;

[0032] Step 5: Use the fourth ultrasonic probe arranged on the measurement pipeline to transmit and receive ultrasonic signals, extract the pulsed-wave Doppler frequency shift between the transmitted signal and the reflected signal, and obtain the water ring thickness according to the oil-phase cross-sectional area described in Step 2 or Step 3. Combined with the sound velocities c o and c w , the measurement of the oil-water separated flow velocity distribution, the separated-phase volume flow rate and the total volume flow rate of the two-phase flow is realized; the fourth ultrasonic probe includes a single self-transmitting and self-receiving wedge probe arranged on one axial side of the measurement pipeline;

[0033] Among them, Step 2, Step 3, Step 4 and Step 5 are implemented separately, or any one of Step 2 and Step 3 is combined with Step 4 or Step 5 in pairs, or implemented together.

[0034] Further, in the second step, the ultrasonic signal emitted by the first ultrasonic probe is perpendicular to the flow direction of the oil-water two-phase flow, and the ultrasonic attenuation coefficient K is obtained according to Formula 1:

[0035]

[0036] where l is the distance between the transmitting end and the receiving end, V t is the amplitude of the ultrasonic emission signal, and V r is the amplitude of the ultrasonic received signal;

[0037] According to the relationship between the ultrasonic attenuation coefficient K and the oil-phase cross-sectional holdup α o K = F(α o ), α o can be obtained;

[0038] Using the formulas α w = 1 - α o , A o = Aα o , A w = Aα w , the water-phase cross-sectional holdup α w , the oil-phase cross-sectional area A o and the water-phase cross-sectional area A w are calculated.

[0039] Further, when the ultrasonic emission frequency is 0.5 MHz and the inner diameter of the measurement pipeline is 50 mm, in the oil-water annular flow with an oil content of 5% - 30%, there is a linear relationship between the ultrasonic attenuation coefficient K and the oil-phase cross-sectional holdup α o K = 0.288α o + 4.648.

[0040] Further, in the third step, the included angle between the ultrasonic signal emitted and received by the second probe and the fluid direction of the oil-water two-phase flow is θ, and the ultrasonic attenuation coefficient K is obtained according to Formula 2:

[0041]

[0042] where is the distance between the transmitting end and the receiving end, and D represents the inner diameter of the measurement pipeline;

[0043] According to the relationship between the ultrasonic attenuation coefficient K and the oil-phase cross-sectional holdup α o K = F(α o ), it can be obtained;

[0044] Using the formulas α w = 1 - α o , A o = Aαo , A w = Aα w , the water-phase cross-sectional holdup α is calculated w , the cross-sectional area A of the oil phase o , the cross-sectional area A of the water phase w .

[0045] Further, in the fourth step, the included angle between the ultrasonic signal transmitted and received by the third ultrasonic probe and the fluid direction is θ. Combining the average Doppler shift and the sound velocity c of the oil-water two-phase mixture m , the velocity u of the oil-water two-phase mixture is obtained m , u m is calculated by Equation 3:

[0046]

[0047] where c m is the sound velocity of the oil-water two-phase mixture, is the average Doppler shift, and f 0 is the central frequency of the ultrasonic emission;

[0048] Combining the cross-sectional area A of the measurement pipeline, the total volume flow rate Q of the two-phase flow is calculated by Equation 4:

[0049] Q = Au m Equation 4

[0050] Combining the cross-sectional phase holdups α o and α w , the separate-phase volume flow rates Q o and Q w of the oil-water two-phase flow are calculated by Equation 5 and Equation 6 respectively:

[0051] Q o = Q·α o Equation 5

[0052] Q w = Q·α w Equation 6

[0053] Further, in the fifth step, the included angle between the ultrasonic signal transmitted and received by the fourth ultrasonic probe and the fluid direction is θ; combining the cross-sectional area A of the oil phase o and the inner diameter D of the measurement pipeline, the water ring thickness δ is obtained according to Equation 7 as: d

[0054]

[0055] According to the pulsed wave Doppler method, the fourth ultrasonic probe emits ultrasonic signals at different times, and receives the reflected ultrasonic signals within the time interval between two adjacent pulses, and obtains the position information x of the oil-water two-phase flow relative to the wall of the measurement pipeline according to Formula 8, Formula 9 and Formula 10:

[0056]

[0057]

[0058]

[0059] Among them, τ represents the time delay of the ultrasonic received signal relative to the transmitted signal, and c w represents the sound velocity in the water phase, and c o represents the sound velocity in the oil phase;

[0060] Extract the Doppler frequency shift f of the received ultrasonic signal relative to the transmitted ultrasonic signal dx , and obtain the phase velocity distribution of the oil-water two-phase according to Formula 11 and Formula 12:

[0061]

[0062]

[0063] Calculate and obtain the oil phase volume flow rate Q o , the water phase volume flow rate Q w and the total volume flow rate Q of the two-phase flow according to Formula 13, Formula 14, and Formula 15:

[0064]

[0065]

[0066] Q = Q o + Q w Formula 15.

[0067] An ultrasonic measurement device and method for oil-water two-phase flow based on in-pipe phase separation provided by the present invention have the following advantageous technical effects:

[0068] 1. In the ultrasonic measurement device and method for oil-water two-phase flow based on in-pipe phase separation of the present invention, the in-pipe phase separation is combined with ultrasonic measurement. By in-pipe phase separation, different inlet flow patterns are converted into oil column-water film flow patterns, which can effectively solve the measurement difficulties brought by flow pattern problems such as different phase holdups, discrete phase particle sizes and positions, and solve the problem of multi-parameter synchronous measurement of oil-water two-phase flow through different arrangement methods of ultrasonic probes.

[0069] 2. In the ultrasonic measurement device for oil-water two-phase flow based on in-tube phase separation of the present invention, a multi-stage phase separation component is adopted. In the primary cyclone structure, the vane-type cyclone is the core of the phase separation component. After separating the six different flow patterns of the oil-water two-phase flow, the discrete phase droplets form a continuous central oil column, while the water phase forms a continuous water ring around the oil column. High-viscosity oil droplets are likely to adhere to the wall surface. Once adhered, they are not easily detached and will rotate forward along the wall surface, basically achieving the in-tube phase separation state, but the oil-water interface is relatively blurred. In the secondary cyclone structure, an orifice plate is added as a filter to reduce large oil bubbles in the oil-water two-phase flow or break them into small droplets and enter the cyclone, which can increase the length of the stable form section of the oil column after swirling, but there are still many oil droplets in the water ring. The tertiary cyclone structure increases the upstream pressure of the oil-water two-phase flow separated by the upstream orifice plate and cyclone, forms an oil core with a more stable form, and also plays a role in rectification, which helps to improve the accuracy of multi-parameter measurement by the ultrasonic measurement device. One, two, or three-stage cyclone structures can be arbitrarily selected to meet various usage requirements, having general applicability.

[0070] 3. An ultrasonic measurement method for oil-water two-phase flow based on in-tube phase separation of the present invention is based on in-tube phase separation, combines two ultrasonic measurement methods, and effectively uses the ultrasonic Doppler method on the basis of obtaining the phase holdup by the ultrasonic attenuation method to achieve synchronous measurement of multiple parameters such as phase holdup, mixture velocity, velocity distribution, and flow rate.

[0071] The concept, specific structure, and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, features, and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 is a schematic structural diagram of the ultrasonic measurement device of the present invention;

[0073] Figure 2 is a schematic structural diagram of the vane-type cyclone;

[0074] Figure 3 is a schematic structural diagram of the ultrasonic measurement component;

[0075] Figure 4 is a schematic diagram of the first installation method of the ultrasonic measurement component;

[0076] Figure 5 is a schematic diagram of the second installation method of the ultrasonic measurement component;

[0077] Figure 6 is a simulation and result diagram of high-water-cut oil-water annular flow;

[0078] Figure 7 is a flowchart of the ultrasonic measurement method for oil-water two-phase flow.

[0079] Among them, 10 - measurement pipeline, 11 - plane, 12 - square coupling block, 20 - phase separation component, 21 - cyclone, 22 - orifice plate, 30 - ultrasonic measurement component, 31 - ultrasonic signal transmitter / receiver, 32 - single crystal probe, 33 - one - transmit - one - receive wedge probe, 34 - self - transmit - self - receive wedge probe, 40 - oil - water two - phase flow. Detailed implementation manners

[0080] The following introduces multiple preferred embodiments of the present invention with reference to the accompanying drawings of the specification to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0081] In the drawings, components with the same structure are denoted by the same numerical labels, and components with similar structures or functions everywhere are denoted by similar numerical labels. The size and thickness of each component shown in the drawings are arbitrarily shown, and the present invention does not limit the size and thickness of each component. To make the illustration clearer, the thickness of some parts in the drawings is appropriately enlarged.

[0082] As Figure 1 shown, the ultrasonic measurement device for oil - water two - phase flow provided by the present invention includes a measurement pipeline 10, a phase separation component 20, and an ultrasonic measurement component 30. The oil - water two - phase flow 40 flows into the measurement pipeline 10. The phase separation component 20 is arranged on the measurement pipeline 10 to perform in - pipe phase separation on the oil - water two - phase flow 40. The ultrasonic measurement component 30 is arranged on the measurement pipeline 10 to realize synchronous multi - parameter measurement of the oil - water two - phase flow by using the ultrasonic measurement method. The phase separation component 20 is composed of a swirling structure. At least one - stage swirling structure is arranged upstream of the measurement pipeline 10 and upstream of the ultrasonic measurement component 30. In some embodiments, a swirling structure can also be arranged downstream of the ultrasonic measurement component 30.

[0083] For the phase separation component 20 of the present invention, according to different actual requirements, one - stage or multi - stage swirling structures can be set, and different swirling structures can also be selected according to different requirements. Specifically as follows:

[0084] In some embodiments, as Figure 1 (a) shows, the phase separation component 20 includes a one - stage swirling structure, which is composed of a vane - type cyclone 21, installed upstream of the measurement pipeline 10 and upstream of the ultrasonic measurement component 30. After the oil - water two - phase flow passes through the vane - type cyclone 21, the phase distribution changes. The oil phase aggregates at the center of the pipeline under the action of centrifugal force to form a continuous oil column, and the water forms a continuous water ring surrounding the oil column.

[0085] In some embodiments, as Figure 1As shown in (b), the phase separation component 20 includes a secondary cyclone structure. Specifically, it includes an orifice plate 22 and a vane type cyclone 21. The orifice plate 22 and the vane type cyclone 21 are sequentially installed on the measurement pipeline 10 along the flow direction, and both are located upstream of the measurement pipeline 10 and upstream of the ultrasonic measurement component 30. In the oil-water two-phase flow, there are irregular large oil bubbles, etc. When flowing through the orifice plate 22, they quickly become smaller or break to form small oil droplets and enter the cyclone 21.

[0086] In some embodiments, as Figure 1 (c) shows, the phase separation component 20 includes a tertiary cyclone structure. Specifically, it includes an orifice plate 22 and two vane type cyclones 21, which are installed in series on the measurement pipeline 10 along the flow direction, and both are located upstream of the measurement pipeline 10 and upstream of the ultrasonic measurement component 30. The oil phase becomes smaller or decomposes through the orifice plate to form small oil droplets, and then enters the two series-connected cyclones 21 along with the water phase. Under the action of centrifugal force, they converge at the center to form an oil column - water circulation type.

[0087] In some embodiments, as Figure 1 (d) shows, the phase separation component 20 includes a tertiary cyclone structure. Specifically, it includes an orifice plate 22 and two vane type cyclones 21, which are installed in series on the measurement pipeline 10 along the flow direction. Among them, the orifice plate 22 and one vane type cyclone 21 are located upstream of the measurement pipeline 10 and upstream of the ultrasonic measurement component 30, and the other vane type cyclone 21 is located downstream of the ultrasonic measurement component 30. The oil-water two-phase flow separated by the upstream orifice plate and cyclone increases the upstream pressure under the action of the downstream cyclone, forming a more stable oil core.

[0088] The vane type cyclone 21 can adopt various structures, such as Figure 2 shown, which respectively show five different structures. It should be understood that the vane type cyclone 21 of the present invention is not limited to these five structures, and other structures that can achieve oil-water two-phase separation can also be applied in the present invention.

[0089] As Figure 2 (a) shows, the first structure is composed of four vanes and a hub unit. The shape of each swirl vane is semi-elliptical. The four swirl vanes are evenly arranged circumferentially. The vane height is the same as the inner diameter of the measurement pipeline 10, the vane thickness is 1 mm, and it is closely attached to the inner wall of the pipeline. One end of the hub unit is hemispherical, and the other end is conical. The height is 1.5 times the vane height and is located at the center of the cyclone device. The normal velocity of the vane surface makes an angle of 45° with the axial direction of the hub unit.

[0090] As Figure 2(As shown in (b), the second structure consists of four blades and a hub unit. The four swirling blades are evenly arranged circumferentially. The shape of each swirling blade is spiral. The height of the blade is 1.5 times the inner diameter of the measuring pipe 10, the thickness of the blade is 1 mm, and it is closely attached to the inner wall of the pipe. One end of the hub unit is hemispherical and the other end is conical. The height is 1.5 times the height of the blade. It is located at the center of the swirling device. The normal velocity of the blade surface makes an angle of 45° with the axial direction of the hub unit.)

[0091] As shown in Figure 2 (c), the third structure consists of four blades and a hub unit. The shape of each swirling blade is spiral. The four swirling blades are evenly arranged circumferentially. The height of the blade is 1.5 times the inner diameter of the measuring pipe 10, the thickness of the blade is 1 mm, and it is closely attached to the inner wall of the pipe. One end of the hub unit is hemispherical and the other end is conical. The height is 1.5 times the height of the blade. It is located at the center of the swirling device. The normal velocity of the blade surface gradually changes from 90° to 45° with the axial direction of the hub unit.)

[0092] As shown in Figure 2 (d), the fourth structure consists of four blades. The shape of each swirling blade is semi-elliptical. The four swirling blades are evenly arranged circumferentially. The height of the blade is the same as the inner diameter of the measuring pipe 10, the thickness of the blade is 1 mm, and it is closely attached to the inner wall of the pipe. The normal velocity of the blade surface makes an angle of 45° with the axial direction of the cyclone 21.)

[0093] As shown in Figure 2 (e), the fifth structure consists of four blades. The shape of each swirling blade is similar to an airfoil blade. The four swirling blades are evenly arranged circumferentially. The height of the blade is 2.5 times the inner diameter of the measuring pipe 10, the thickness of the blade is 1 mm, and it is closely attached to the inner wall of the pipe. At the 1 / 2 height of the blade, the normal velocity of the blade surface gradually changes from 90° to 30° with the axial direction of the cyclone 21.)

[0094] As shown in Figure 3 shown, the ultrasonic measurement assembly includes an ultrasonic signal transmitter-receiver 31 and at least one ultrasonic probe electrically connected thereto. The ultrasonic probe is arranged on the side wall of the measuring pipe 10. The ultrasonic probe has types such as a probe with one transmitter and one receiver, and a probe with self-transmitting and self-receiving. Among them, generally one set of probes with one transmitter and one receiver is required. One probe is used to transmit ultrasonic signals and the other probe is used to receive ultrasonic signals. For a set of probes with one transmitter and one receiver, the two probes can be installed on the same side of the measuring pipe axially, that is, the two probes are arranged in sequence along the axial direction of the measuring pipe; or the two probes can be installed on the opposite sides of the measuring pipe axially, that is, the two probes are respectively arranged on the opposite sides of the measuring pipe. According to specific requirements, different types of ultrasonic probes and arrangement methods can be selected. As shown in Figure 3 shown, the present invention provides five arrangement methods:

[0095] The first arrangement method, as shown inFigure 3 As shown in (a), it includes a set of single-crystal probes 32 for one transmitting and one receiving. Among them, the two single-crystal probes 32 are respectively arranged on the opposite sides of the axial direction of the measurement pipeline 10.

[0096] The second arrangement method is as Figure 3 shown in (b), which includes a set of wedge probes 33 for one transmitting and one receiving. The two wedge probes 33 are respectively located on the same side of the axial direction of the measurement pipeline 10, and the two wedge probes 33 are closely attached to each other along this axial direction.

[0097] The third arrangement method is as Figure 3 shown in (c), which includes a self-transmitting and self-receiving wedge probe 34, and this wedge probe 34 is arranged separately on the measurement pipeline 10.

[0098] The fourth arrangement method is as Figure 3 shown in (d), which includes a set of single-crystal probes 32 for one transmitting and one receiving, and their arrangement method is the same as that of Figure 3 (a), and a set of wedge probes 33 for one transmitting and one receiving, and their arrangement method is the same as that of Figure 3 (b).

[0099] The fifth arrangement method is as Figure 3 shown in (e), which includes a set of single-crystal probes 32 for one transmitting and one receiving, and their arrangement method is the same as that of Figure 3 (a), and a self-transmitting and self-receiving wedge probe 34, and their arrangement method is the same as that of Figure 3 (c).

[0100] There are various installation methods for the ultrasonic probe. For example, as Figure 4 shown, the surface on one side of the measurement pipeline 10 downstream of the phase separation component 20 is flattened to form a plane 11, and then the probe is installed and fixed on this plane 11. This installation method enables the probe to be installed closely against the flat pipe wall, avoiding the measurement error caused by circular pipe installation. As Figure 5 shown, a square coupling block 12 is added to the measurement pipeline 10 downstream of the phase separation component 20 and fixed to the pipeline with fasteners, and then the probe is installed and fixed on the square coupling block 12. Connecting the probe and the pipe wall through the square coupling block 12 can also avoid the measurement error caused by circular pipe installation. It should be understood that other installation methods that can effectively reduce the ultrasonic measurement error can also be applied in the present invention.

[0101] The present invention also provides a method for ultrasonic measurement of oil-water two-phase flow using the above ultrasonic measurement device. This measurement method is based on in-pipe phase separation, combines the ultrasonic attenuation method and the ultrasonic Doppler method to measure the fluid after phase separation of the oil-water two-phase flow, and can realize synchronous measurement of multiple parameters such as phase holdup, mixing velocity, flow velocity distribution, and flow rate. It mainly includes the following steps:

[0102] Step 1: Separate the oil-water two-phase flow 40 inside the measurement pipeline 10 into phases within the pipeline;

[0103] Step 2: Based on the ultrasonic attenuation method, use the ultrasonic probe on the first arrangement mode of the measurement pipeline 10 to transmit and receive ultrasonic signals, calculate the cross-sectional holdup of the oil-water two-phase separated phases, and then obtain the cross-sectional area of the oil-water two-phase separated phases;

[0104] Step 3: Based on the ultrasonic attenuation method, use the ultrasonic probe on the second or third arrangement mode of the measurement pipeline 10 to transmit and receive ultrasonic signals, calculate the cross-sectional holdup of the oil-water two-phase separated phases, and then obtain the cross-sectional area of the oil-water two-phase separated phases;

[0105] Step 4: Based on the continuous-wave ultrasonic Doppler method, use the ultrasonic probe on the second or fourth arrangement mode of the measurement pipeline 10 to transmit and receive ultrasonic signals, obtain the average Doppler shift through spectrum analysis to calculate the mixed velocity of the oil-water two-phase flow, and combine with the cross-sectional area and cross-sectional holdup of the oil-water phase separation of the measurement pipeline 10 described in Step 2 or Step 3 to measure the total volume flow rate and the separated-phase volume flow rate of the two-phase flow;

[0106] Step 5: Based on the pulsed-wave ultrasonic Doppler method, use the ultrasonic probe on the third or fifth arrangement mode of the measurement pipeline 10 to transmit and receive ultrasonic signals, extract the pulsed-wave Doppler shift between the transmitted and reflected signals, and combine with the cross-sectional area of the oil phase of the measurement pipeline 10 described in Step 2 or Step 3 to obtain the water ring thickness, and realize the measurement of the separated-phase flow velocity distribution, the separated-phase volume flow rate and the total volume flow rate of the oil-water two-phase flow;

[0107] Among them, the ultrasonic attenuation method can be realized by any one of a single-crystal probe 32 with one transmitting and one receiving (the ultrasonic signal it emits is perpendicular to the flow direction), a wedge probe 33 with one transmitting and one receiving (the angle between the ultrasonic signal it emits and the fluid direction is θ), and a wedge probe 34 with single self-transmitting and self-receiving (the angle between the ultrasonic signal it emits and the fluid direction is θ). The continuous-wave ultrasonic Doppler method can be realized based on a wedge probe 33 with one transmitting and one receiving. The pulsed-wave ultrasonic Doppler method can be realized based on a single self-transmitting and self-receiving wedge probe 34. In actual application, different combinations of probe types (a single-crystal probe 32 with one transmitting and one receiving, a wedge probe 33 with one transmitting and one receiving, a single self-transmitting and self-receiving wedge probe 34) can be selected according to actual needs to realize the ultrasonic attenuation method, the pulsed-wave ultrasonic Doppler method and the continuous-wave ultrasonic Doppler method. According to the different probe types selected, the above Step 2, Step 3, Step 4, and Step 5 can be implemented separately for each step, or any one of Step 2 and Step 3 can be selected and combined with Step 4 and Step 5 in pairs for implementation, or implemented together.

[0108] The following lists several implementation manners of the present invention to further illustrate the principle of the present invention.

[0109] The first manner:

[0110] The first arrangement of the ultrasonic probe is as shown in Figure 3 (a), and it includes a set of single-crystal probes 32 for one transmitting and one receiving. The two single-crystal probes 32 are respectively installed on the opposite sides of the axial direction of the measurement pipeline 10, and the ultrasonic signal is vertically emitted. One of the single-crystal probes 32 emits ultrasonic signals, and the single-crystal probe 32 on the opposite side receives the ultrasonic signals.

[0111] According to the ultrasonic attenuation method, the ultrasonic transmitter emits ultrasonic waves with a certain frequency and intensity, which pass through the oil-water two-phase flow. After passing through the attenuation mechanisms such as absorption, scattering, and reflection of the oil-water two-phase, they reach the ultrasonic signal receiver. The amplitude V of the ultrasonic emission signal is extracted t and the amplitude V of the received signal r . Combining the distance l between the transmitter and the receiver, the ultrasonic attenuation coefficient K can be obtained according to Formula 1

[0112]

[0113] According to the specific relationship between the ultrasonic attenuation coefficient K and the oil-phase cross-sectional holdup α o , that is, K = F(α o ), α o can be obtained. Thus, according to the formula α w = 1 - α o , the water-phase cross-sectional holdup α w can be obtained. Combining the oil-water phase cross-sectional holdups α o , α w and the pipeline cross-sectional area A, the oil-phase cross-sectional area A o and the water-phase cross-sectional area A w are calculated. The calculation formulas are A o = Aα o , A w = Aα w . Among them, the specific relationship between the ultrasonic attenuation coefficient K and the oil-phase cross-sectional holdup α o , that is, K = F(α o ), can be obtained through experimental calibration or simulation. For example, in the simulation of high-water-cut oil-water annular flow, the inner diameter of the measurement pipeline is 50 mm, and the oil-phase distribution is simulated by a circle at the center of the pipeline cross-section. By controlling the area of the circle, different cross-sectional oil holdups are obtained. The single-transmitting and single-receiving ultrasonic measurement mode is adopted, and the transmitting frequency of the ultrasonic probe is 0.5 MHz. This simulation uses a viscous model to simulate high-water-cut oil-water annular flow with an oil holdup of 5% - 30%. Finally, the linear relationship between the ultrasonic attenuation coefficient K and the oil-phase cross-sectional holdup α o is obtained as K = 0.288α o + 4.648. The specific simulation structure model and results are as shown in Figure 6 .

[0114] The second method:

[0115] The second arrangement of the ultrasonic probe is as shown in Figure 3 (b), and it includes a set of wedge probes 33 with one transmitter and one receiver. Among them, for the two wedge probes 33, one transmits ultrasonic signals and the other receives ultrasonic signals. The included angle between the incident sound wave of the ultrasonic signal and the fluid flow direction of the measurement pipeline is θ. According to the ultrasonic attenuation method, the amplitudes V t and V r of the ultrasonic signals at the transmitter and receiver ends are extracted. Combining with the distance between the transmitter and receiver ends the ultrasonic attenuation coefficient K is obtained according to Formula 2

[0116]

[0117] According to the specific relationship between the ultrasonic attenuation coefficient K and the oil-phase cross-sectional holdup α o K = F(α o ), α o can be obtained. K = F(α o ) can be obtained through experimental calibration or simulation. Thus, according to the formula α w = 1 - α o , the water-phase cross-sectional holdup α w can be obtained. Combining the oil-water phase-separated cross-sectional holdups α o , α w and the pipeline cross-sectional area A, the oil-phase cross-sectional area A o and the water-phase cross-sectional area A w are calculated. The calculation formulas are A o = Aα o , A w = Aα w .

[0118] According to the continuous-wave ultrasonic Doppler method, the ultrasonic signals with Doppler frequency shift information reflected by oil droplets and water droplets in the oil-water two-phase flow are received by the wedge probe 33, and the measurement space includes the entire pipeline cross-section on the probe side. After analyzing the spectrum of the ultrasonic signal at the receiving end, the average Doppler frequency shift is obtained. Combining with the oil-water two-phase mixed sound speed c m , the oil-water two-phase mixed velocity u m can be obtained and calculated according to Formula 3:

[0119]

[0120] Combining with the pipeline cross-sectional area A, the total volume flow rate Q of the two-phase flow is calculated according to Formula 4:

[0121] Q = Au m Formula 4

[0122] Combining the oil-water two-phase flow phase-separated cross-sectional holdups α o and α w, the separated-phase volume flow rates of the oil-water two-phase flow, Q o and Q w :

[0123] Q o = Q·α o Equation 5

[0124] Q w = Q·α w Equation 6

[0125] The third method:

[0126] The third arrangement of the ultrasonic probe is as shown in Figure 3 (c), which includes a single self-transmitting and self-receiving wedge probe 34 installed on the measurement pipeline. The wedge probe 34 emits ultrasonic signals at different times and receives the reflected signals from the oil droplets in water and water droplets in oil during the time interval between two adjacent pulses. The measurement space is cylindrical, and the included angle between the incident sound wave of the ultrasonic signal and the fluid flow direction of the measurement pipeline is θ. According to the ultrasonic attenuation method, the ultrasonic attenuation coefficient K is obtained according to Equation 2

[0127]

[0128] Extract the amplitude V t of the ultrasonic emission signal and the amplitude V r of the received signal. Combining the distance between the transmitter and the receiver to obtain the ultrasonic attenuation coefficient K. According to the specific relationship between the ultrasonic attenuation coefficient K and the oil-phase cross-sectional holdup α o K = F(α o ), α o can be obtained. K = F(α o ) can be obtained through experimental calibration or simulation. Thus, according to the formula α w = 1 - α o , the water-phase cross-sectional holdup α w can be obtained. Combining the oil-water separated-phase cross-sectional holdups α o , α w and the pipeline cross-sectional area A, the oil-phase cross-sectional area A o and the water-phase cross-sectional area A w are calculated. The calculation formulas are A o = Aα o , A w = Aα w . Combining the oil-phase cross-sectional area A o , the water ring thickness δ is obtained according to Equation 7

[0129]

[0130] According to the pulsed wave Doppler method, the wedge probe 34 that emits and receives signals by itself emits ultrasonic signals at different times, and receives the reflected ultrasonic signals within the time interval between two adjacent pulses. The position information x of the oil-water two-phase flow relative to the wall of the measurement pipeline 10 is obtained according to Formulas 8, 9, and 10:

[0131]

[0132]

[0133]

[0134] where τ represents the time delay of the ultrasonic received signal relative to the transmitted signal; c w represents the sound velocity in the water phase; c o represents the sound velocity in the oil phase.

[0135] Extract the Doppler frequency shift f of the ultrasonic received signal relative to the transmitted signal dx , and obtain the phase flow velocity distributions of the oil and water phases according to Formulas 11 and 12:

[0136]

[0137]

[0138] Measure the oil-phase phase volume flow rate Q o , the water-phase phase volume flow rate Q w and the total volume flow rate Q of the two-phase flow according to Formulas 13, 14, and 15:

[0139]

[0140]

[0141] Q = Q o + Q w Formula 15.

[0142] The fourth method:

[0143] The fourth arrangement method of the ultrasonic probe is as Figure 3As shown in (d), it includes a set of single-crystal probes 32 for one transmitting and one receiving and a set of wedge probes 33 for one transmitting and one receiving. The two single-crystal probes 32 are respectively installed on the opposite sides of the measurement pipeline in the axial direction. The ultrasonic signals are vertically transmitted. One single-crystal probe 32 on one side emits ultrasonic signals, and the single-crystal probe 32 on the opposite side receives the ultrasonic signals. One of the two wedge probes 33 emits ultrasonic signals, and the other receives ultrasonic signals. The included angle between the incident sound wave of the ultrasonic signal and the fluid flow direction of the measurement pipeline is θ, and the measurement space includes the entire pipeline cross-section on the probe side. According to the ultrasonic attenuation method, the ultrasonic wave emitter emits ultrasonic waves with a certain frequency and intensity, which pass through the oil-water two-phase flow and reach the ultrasonic signal receiver through attenuation mechanisms such as absorption, scattering, and reflection of the oil-water two phases. The ultrasonic attenuation coefficient K is obtained according to Formula 1

[0144]

[0145] Extract the amplitude V of the ultrasonic emission signal t and the amplitude V of the received signal r , and combine the distance l between the transmitter and the receiver to obtain the ultrasonic attenuation coefficient K. According to the specific relationship K = F(α o ) between the ultrasonic attenuation coefficient K and the oil-phase cross-sectional holdup α o , α o can be obtained, and thus α w = 1 - α o can be used to obtain the water-phase cross-sectional holdup α w . Combine the oil-water phase cross-sectional holdups α o , α w and the pipeline cross-sectional area A to calculate the oil-phase cross-sectional area A o and the water-phase cross-sectional area A w . The calculation formulas are A o = Aα o , A w = Aα w . Among them, K = F(α o ) can be obtained through experimental calibration or simulation. For example, in the simulation of high-water-cut oil-water annular flow, the inner diameter of the measurement pipeline is 50 mm. The oil-phase distribution is simulated by a circle at the center of the pipeline cross-section, and different cross-sectional oil holdups are controlled by the area of the circle. The single-transmitting and single-receiving ultrasonic measurement mode is adopted, and the emission frequency of the ultrasonic probe is 0.5 MHz. This simulation uses a viscous model to simulate high-water-cut oil-water annular flow with an oil holdup of 5% - 30%. Finally, the linear relationship between the ultrasonic attenuation coefficient K and the oil-phase cross-sectional holdup α o is obtained as K = 0.288α o +4.648. The specific simulation structure model and results are as shown in Figure 6 .

[0146] According to the continuous wave ultrasonic Doppler method, the ultrasonic signal with Doppler frequency shift information reflected by oil droplets and water droplets in the oil-water two-phase flow is received by the wedge probe 33, and the measurement space includes the entire pipeline cross-section on the probe side. The average Doppler frequency shift is obtained through the spectral analysis of the ultrasonic signal at the receiving end. Combined with the sound velocity c of the oil-water two-phase mixture m , the mixed velocity u of the oil-water two-phase flow can be obtained m , calculated according to Equation 3

[0147]

[0148] Combined with the pipeline cross-sectional area A, the total volume flow rate Q of the two-phase flow is calculated according to Equation 4:

[0149] Q = Au m Equation 4

[0150] Combined with the cross-sectional holdup α of the oil-water two-phase flow o and α w , the phase-separated volume flow rates Q o and Q w :

[0151] Q o = Q·α o Equation 5

[0152] Q w = Q·α w Equation 6

[0153] The fifth method:

[0154] The fifth layout of the ultrasonic probe is as shown in Figure 3 (e), and includes a set of single-crystal probes 32 with one transmitting and one receiving, and a wedge probe 34 with self-transmitting and self-receiving. The two single-crystal probes 32 are respectively installed on the opposite sides of the axial direction of the measurement pipeline. One single-crystal probe 32 emits ultrasonic signals, and the single-crystal probe 32 on the opposite side receives the ultrasonic signals. The wedge probe 34 is installed on one side of the axial direction of the measurement pipeline. The wedge probe 34 emits ultrasonic signals and receives ultrasonic signals. The included angle between the incident sound wave of the ultrasonic signal and the fluid flow direction of the measurement pipeline is θ. According to the ultrasonic attenuation method, the ultrasonic transmitter emits ultrasonic waves with a certain frequency and intensity, which pass through the oil-water two-phase flow and reach the ultrasonic signal receiver through attenuation mechanisms such as absorption, scattering, and reflection of the oil-water two-phase flow. The ultrasonic attenuation coefficient K is obtained according to Equation 1

[0155]

[0156] Extract the amplitude V of the ultrasonic emission signal t and the amplitude V of the received signal r, the ultrasonic attenuation coefficient K is obtained by combining the distance l between the transmitter and the receiver. According to the specific relationship between the ultrasonic attenuation coefficient K and the oil-phase cross-sectional holdup α o , i.e., K = F(α o ), α o can be obtained. Thus, the water-phase cross-sectional holdup α w can be obtained according to the formula α o = 1 - α w . By combining the oil-water phase cross-sectional holdups α o , α w and the pipe cross-sectional area A, the oil-phase cross-sectional area A o and the water-phase cross-sectional area A w are calculated. The calculation formulas are A o = Aα o , A w = Aα w . Among them, K = F(α o ) can be obtained through experimental calibration or simulation. For example, in the simulation of high-water-cut oil-water annular flow, the inner diameter of the pipe is measured to be 50 mm. The oil-phase distribution is simulated by a circle at the center of the pipe cross-section, and different cross-sectional oil holdups are obtained by controlling the area of the circle. The single-transmission and single-reception ultrasonic measurement mode is adopted, and the transmission frequency of the ultrasonic probe is 0.5 MHz. This simulation uses a viscous model to simulate high-water-cut oil-water annular flow with an oil holdup of 5% - 30%. Finally, the linear relationship between the ultrasonic attenuation coefficient K and the oil-phase cross-sectional holdup α o is obtained as K = 0.288α o + 4.648. The specific simulation structure model and results are as shown in Figure 6 . By combining the oil-phase cross-sectional area A o , the water ring thickness δ is obtained according to formula 7:

[0157]

[0158] According to the pulsed-wave Doppler method, the wedge probe 34 emits ultrasonic signals in a time-sharing manner and receives the reflected ultrasonic signals within the time interval between two adjacent pulses. The position information x of the oil-water two-phase flow relative to the wall of the measurement pipe 10 is obtained according to formulas 8, 9, and 10:

[0159]

[0160]

[0161]

[0162] The Doppler frequency shift f of the ultrasonic received signal relative to the transmitted signal is extracted dx , and the phase velocity distributions of the oil-water two phases are obtained according to formulas 11 and 12:

[0163]

[0164]

[0165] Implement the oil-phase separated volume flow rate Q according to Formula 13, Formula 14, and Formula 15 o , the water-phase separated volume flow rate Q w and the measurement of the total volume flow rate Q of the two-phase flow:

[0166]

[0167]

[0168] Q = Q o + Q w Formula 15

[0169] The above introduced five implementation manners, among which:

[0170] The first implementation manner uses a single-crystal probe with one transmitting and one receiving + ultrasonic attenuation method to obtain the void fraction and cross-sectional area of the separated phases of the oil-water two-phase flow;

[0171] The second implementation manner uses a wedge probe with one transmitting and one receiving + ultrasonic attenuation method to obtain the void fraction and cross-sectional area of the separated phases of the oil-water two-phase flow, calculates the mixed flow velocity of the oil-water two-phase flow and the total volume flow rate of the two-phase flow by using the continuous-wave ultrasonic Doppler method, and obtains the separated volume flow rate in combination with the void fraction of the oil-water separated cross-section;

[0172] The third implementation manner uses a self-transmitting and self-receiving wedge probe + ultrasonic attenuation method to obtain the void fraction of the separated phases of the oil-water two-phase flow, the separated cross-sectional area and the water ring thickness, calculates the velocity distribution of the oil-water separated phases by using the pulsed-wave ultrasonic Doppler method, and obtains the separated volume flow rate and the total volume flow rate of the two-phase flow in combination with the oil-water separated cross-sectional area;

[0173] The fourth implementation manner uses a single-crystal probe with one transmitting and one receiving + ultrasonic attenuation method to obtain the void fraction and cross-sectional area of the separated phases of the oil-water two-phase flow; uses a wedge probe with one transmitting and one receiving + continuous-wave ultrasonic Doppler method to obtain the mixed flow velocity of the oil-water two-phase flow and the total volume flow rate of the two-phase flow, and realizes the measurement of the separated volume flow rate of the two-phase flow in combination with the void fraction of the oil-water separated cross-section;

[0174] The fifth implementation manner uses a single-crystal probe with one transmitting and one receiving + ultrasonic attenuation method to obtain the void fraction of the separated phases of the oil-water two-phase flow, the separated cross-sectional area and the water ring thickness; uses a self-transmitting and self-receiving wedge probe + pulsed-wave ultrasonic Doppler method to calculate the velocity distribution of the oil-water separated phases, and obtains the separated volume flow rate and the total volume flow rate of the two-phase flow in combination with the oil-water separated cross-sectional area.

[0175] It should be understood that the embodiments of the present invention are not limited to the above five methods, and other combination methods are also included. For example: one-transmitting and one-receiving wedge probe + ultrasonic attenuation method; one-transmitting and one-receiving wedge probe + continuous wave ultrasonic Doppler method; self-transmitting and self-receiving wedge probe + ultrasonic attenuation method; self-transmitting and self-receiving wedge probe + pulsed wave ultrasonic Doppler method. The appropriate combination method can be selected according to the parameters to be actually measured, such as the cross-sectional void fraction of oil-water two-phase flow, cross-sectional area of the separated phase, velocity distribution of the separated phase, volumetric flow rate of the separated phase, mixed velocity, total volumetric flow rate, etc., so as to realize the measurement of each parameter and the synchronous measurement of multiple parameters.

[0176] One of the following three types of probes can be selected, two of them can be combined, or all three can be selected for measurement: a group of one-transmitting and one-receiving single crystal probes, a group of one-transmitting and one-receiving wedge probes, and a single self-transmitting and self-receiving wedge probe.

[0177] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative labor. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field according to the concept of the present invention through logical analysis, reasoning, or limited experiments on the basis of the prior art should be within the protection scope determined by the claims.

Claims

1. An ultrasonic measurement device for oil-water two-phase flow based on in-pipe phase separation, characterized in that, it includes: a measurement pipeline through which the oil-water two-phase flow passes; a phase separation component arranged on the measurement pipeline; an ultrasonic measurement component arranged on the measurement pipeline; wherein, the phase separation component includes at least one stage of swirl structure; the ultrasonic measurement component includes an ultrasonic signal transmitter-receiver, and at least one ultrasonic probe electrically connected to the ultrasonic signal transmitter-receiver, wherein the ultrasonic probe is arranged on the measurement pipeline, the measurement method of the ultrasonic measurement device for oil-water two-phase flow includes: Step 1: Perform in-pipe phase separation on the oil-water two-phase flow flowing through the measurement pipeline; Step 2: Use the first ultrasonic probe arranged on the measurement pipeline to transmit and receive ultrasonic signals, and obtain the ultrasonic attenuation coefficient K by extracting the amplitudes V of the ultrasonic signals at the transmitting end and the receiving end. According to the specific relationship between the ultrasonic attenuation coefficient K and the oil phase cross-sectional holdup α, i.e., K = F(α), the oil phase cross-sectional holdup α can be obtained. Further calculate the water phase cross-sectional holdup α, and calculate the oil-water phase separation cross-sectional areas A and A by combining with the pipeline cross-sectional area A. The first ultrasonic probe includes a single crystal probe arranged in a one-transmitting-one-receiving mode on the axial opposite sides of the measurement pipeline. t and V r , combine the distance l between the transmitting end and the receiving end to obtain the ultrasonic attenuation coefficient K; according to the specific relationship between the ultrasonic attenuation coefficient K and the oil phase cross-sectional holdup α o , i.e., K = F(α o ), the oil phase cross-sectional holdup α can be obtained. Further calculate the water phase cross-sectional holdup α o , and calculate the oil-water phase separation cross-sectional areas A w and A o by combining with the pipeline cross-sectional area A w ; the first ultrasonic probe includes a single crystal probe arranged in a one-transmitting-one-receiving mode on the axial opposite sides of the measurement pipeline. Step 3: Use the second ultrasonic probe arranged on the measurement pipeline to transmit and receive ultrasonic signals, and extract the amplitudes V of the ultrasonic signals at the transmitting end and the receiving end t and V r . Combine the distance between the transmitting end and the receiving end to obtain the ultrasonic attenuation coefficient K, where D represents the inner diameter of the measurement pipeline, and θ represents the included angle between the ultrasonic signals transmitted and received by the second ultrasonic probe and the fluid direction of the oil-water two-phase flow; According to the specific relationship between the ultrasonic attenuation coefficient K and the oil-phase cross-sectional holdup α o , the oil-phase cross-sectional holdup α o can be obtained. Further calculate the water-phase cross-sectional holdup α w , and calculate the oil-water phase-separated cross-sectional areas A o and A w by combining with the pipeline cross-sectional area A; The second ultrasonic probe includes a set of one-transmitting and one-receiving wedge probes arranged on the same side of the axial direction of the measurement pipeline or a single self-transmitting and self-receiving wedge probe arranged on one side of the axial direction of the measurement pipeline. Step 4: Use the third ultrasonic probe installed on the measurement pipeline to transmit and receive ultrasonic signals, and perform spectral analysis on the received ultrasonic signals to obtain the average Doppler frequency shift Combine with the acoustic velocity c of the oil-water two-phase mixture m , to obtain the oil-water two-phase mixture velocity u m ; Combine with the oil-water phase separation cross-sectional area and cross-sectional void fraction described in Step 2 or Step 3 to achieve the measurement of the total volume flow rate and the phase-separated volume flow rate of the two-phase flow; the third ultrasonic probe includes a set of wedge probes arranged on the same side of the axial direction of the measurement pipeline for one transmission and one reception; Step Five: Use the fourth ultrasonic probe installed on the measurement pipeline to transmit and receive ultrasonic signals, extract the pulsed-wave Doppler frequency shift between the transmitted signal and the reflected signal, and obtain the water ring thickness based on the oil-phase cross-sectional area described in Step Two or Step Three. Combine the sound velocities c o and c w , to achieve the measurement of the oil-water phase velocity distribution, the phase volume flow rate, and the total volume flow rate of the two-phase flow; the fourth ultrasonic probe includes a single self-transmitting and self-receiving wedge probe arranged on one axial side of the measurement pipeline; Optionally, one of Step 2 and Step 3 is combined with Step 4 or Step 5 in pairs for implementation.

2. The ultrasonic measurement device according to claim 1, characterized in that, the at least one stage of swirl structure includes a vane-type cyclone, and the vane-type cyclone is located upstream of the ultrasonic measurement component; or the at least one stage of swirl structure includes an orifice plate and a vane-type cyclone, and the orifice plate and the vane-type cyclone are arranged in series upstream of the ultrasonic measurement component in sequence; or the at least one stage of swirl structure includes an orifice plate and two vane-type cyclones, and the orifice plate and the two vane-type cyclones are arranged in series upstream of the ultrasonic measurement component in sequence, or the orifice plate and one of the vane-type cyclones are arranged in series upstream of the ultrasonic measurement component in sequence, and the other vane-type cyclone is arranged downstream of the ultrasonic measurement component.

3. The ultrasonic measurement device according to claim 2, characterized in that: the structure of the vane-type cyclone is selected from any one of the following five structures: Structure 1, the vane-type cyclone is composed of four swirl vanes and a hub unit. The shape of each swirl vane is semi-elliptical. The four swirl vanes are evenly arranged circumferentially. The vane height is the same as the inner diameter of the measurement pipeline. The vane thickness is 1 mm and it is close to the inner wall of the pipeline. One end of the hub unit is hemispherical and the other end is conical. The height is 1.5 times the vane height and it is located at the center of the vane-type cyclone. The normal velocity of the vane surface makes an angle of 45° with the axial direction of the hub unit; Structure 2, the vane-type cyclone is composed of four swirl vanes and a hub unit. The four swirl vanes are evenly arranged circumferentially. The shape of each swirl vane is spiral. The vane height is 1.5 times the inner diameter of the measurement pipeline. The vane thickness is 1 mm and it is close to the inner wall of the pipeline. One end of the hub unit is hemispherical and the other end is conical. The height is 1.5 times the vane height and it is located at the center of the vane-type cyclone. The normal velocity of the vane surface makes an angle of 45° with the axial direction of the hub unit; Structure Three: The vane type cyclone is composed of four swirling vanes and a hub unit. Each of the swirling vanes is in a spiral shape. The four swirling vanes are evenly arranged circumferentially. The vane height is 1.5 times the inner diameter of the measuring pipe, the vane thickness is 1 mm, and it is closely attached to the inner wall of the pipe. One end of the hub unit is hemispherical and the other end is conical. The height is 1.5 times the vane height and it is located at the center of the vane type cyclone. The normal velocity of the vane surface gradually changes from 90° to 45° with the axial direction of the hub unit. Structure Four: The vane type cyclone is composed of four swirling vanes. Each of the swirling vanes is in a semi-elliptical shape. The four swirling vanes are evenly arranged circumferentially. The vane height is the same as the inner diameter of the measuring pipe, the vane thickness is 1 mm, and it is closely attached to the inner wall of the pipe. The normal velocity of the vane surface forms an angle of 45° with the axial direction of the vane type cyclone. Structure Five: The vane type cyclone is composed of four swirling vanes. Each of the swirling vanes is in a wing shape. The four swirling vanes are evenly arranged circumferentially. The vane height is 2.5 times the inner diameter of the measuring pipe, the vane thickness is 1 mm, and it is closely attached to the inner wall of the pipe. At the 1 / 2 of the vane height, the normal velocity of the vane surface gradually changes from 90° to 30° with the axial direction of the vane type cyclone.

4. The ultrasonic measuring device according to claim 1, characterized in that, in the second step, the ultrasonic signal emitted by the first ultrasonic probe is perpendicular to the flow direction of the oil-water two-phase flow. The ultrasonic attenuation coefficient K is obtained according to Formula 1: where l is the distance between the transmitting end and the receiving end, V t is the amplitude of the ultrasonic transmitting signal, and V r is the amplitude of the ultrasonic receiving signal; According to the relationship between the ultrasonic attenuation coefficient K and the oil-phase cross-sectional holdup α o which is K = F(α o ), α o can be obtained; Using the formula α w = 1 - α o , A o = Aα o , A w = Aα w , the aqueous phase cross-sectional fraction α w , the cross-sectional area A of the oil phase o and the cross-sectional area A of the aqueous phase w are calculated and obtained.

5. The ultrasonic measuring device according to claim 4, characterized in that, When the ultrasonic emission frequency is 0.5 MHz and the inner diameter of the measurement pipeline is 50 mm, in the oil-water annular flow with an oil content of 5% to 30%, the ultrasonic attenuation coefficient K and the oil-phase cross-sectional content α o have a linear relationship K = 0.288α o + 4.

648.

6. The ultrasonic measuring device according to claim 1, characterized in that, in the third step, the angle between the ultrasonic signal emitted and received by the second ultrasonic probe and the fluid direction of the oil-water two-phase flow is θ. The ultrasonic attenuation coefficient K is obtained according to Formula 2: Wherein, is the distance between the transmitting end and the receiving end, and D represents the inner diameter of the measurement pipeline; According to the relationship between the ultrasonic attenuation coefficient K and the oil-phase cross-sectional holdup α o which is K = F(α o ), it can be obtained; Using the formula α w = 1 - α o , A o = Aα o , A w = Aα w , the water phase cross-sectional holdup α w , the oil phase cross-sectional area A o , the water phase cross-sectional area A w is calculated.

7. The ultrasonic measuring device according to claim 1, characterized in that, In the fourth step, the included angle between the ultrasonic signal transmitted and received by the third ultrasonic probe and the fluid direction of the oil-water two-phase flow is θ. Combining with the average Doppler frequency shift and the oil-water two-phase mixed sound speed c m obtain the oil-water two-phase mixed velocity u m , u m is calculated by Equation 3: Among them, c m is the sound velocity of the oil-water two-phase mixture, is the average Doppler frequency shift, f 0 is the ultrasonic emission center frequency; combining with the cross-sectional area A of the measuring pipe, the total volume flow rate Q of the two-phase flow is calculated through Formula 4: Q = Au m Equation 4 Combined with the cross-sectional phase holdup α of the oil-water two-phase flow o and α w , the separated-phase volume flow rates Q o and Q w are calculated respectively through Formula 5 and Formula 6 as follows: Q o = Q·α o Equation 5 Q w = Q·α w Formula 6.

8. The ultrasonic measuring device according to claim 1, characterized in that, In the fifth step, the included angle between the ultrasonic signal transmitted and received by the fourth ultrasonic probe and the fluid direction of the oil-water two-phase flow is θ; combining the cross-sectional area A of the oil phase o and the inner diameter D of the measurement pipeline, the water ring thickness δ is obtained according to Formula 7 as follows: according to the pulsed wave Doppler method, the fourth ultrasonic probe emits ultrasonic signals at different times and receives the reflected ultrasonic signals within the time interval between two adjacent pulses. The position information x of the oil-water two-phase flow relative to the inner wall of the measuring pipe is obtained according to Formulas 8, 9 and 10: Among them, τ represents the time delay of the ultrasonic received signal relative to the transmitted signal, and c w represents the sound velocity in the aqueous phase, and c o represents the sound velocity in the oil phase; Extract the Doppler frequency shift f of the received ultrasonic signal relative to the transmitted ultrasonic signal dx , and obtain the separated-phase flow velocity distributions of the oil and water phases according to Formula 11 and Formula 12: The oil phase volume flow rate Q is calculated according to Equation 13, Equation 14, and Equation 15 o , the water phase volume flow rate Q w and the total volume flow rate Q of the two-phase flow: Q = Q o +Q w Formula 15.

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