Double differential pressure type multiphase flow metering device

Abstract

The utility model belongs to the technical field of flow measurement, and particularly relates to a double differential pressure type multiphase flow metering device which comprises a multiphase flow metering body, the multiphase flow metering body comprises a water content meter and a control box, the water content meter is provided with a multiphase inflow pipe and a multiphase outflow pipe, the multiphase inflow pipe is provided with a pressure transmitter and a wedge-shaped throttling element, and the wedge-shaped throttling element is connected with the control box. A temperature transmitter is arranged on the multiphase outflow pipe, and a first differential pressure transmitter and a second differential pressure transmitter are further arranged on the water content meter; the first differential pressure transmitter comprises a first pressure tapping pipe, a second pressure tapping pipe and a first transmitter gauge outfit; through the cooperation of the first differential pressure transmitter, the water content meter, the second differential pressure transmitter, the control box and other structures, the thick oil block can be effectively prevented from blocking the pressure guide pipe, the pressure tapping is in flange connection with the pipeline, the maintenance is convenient, a group of coefficients is obtained through laboratory calibration, and the cost is reduced. And the system error is minimized under different gas-liquid flows.

Description

Technical Field

[0001] The utility model belongs to the technical field of flow measurement, and particularly relates to a double differential pressure type multiphase flow metering device. Background Technique

[0002] The differential pressure flowmeter is based on the throttling principle of fluid flow and realizes flow measurement by using the pressure difference generated when the fluid flows through the throttling device. It is one of the most mature and commonly used methods for measuring flow in production at present. It is usually composed of a throttling device that can convert the measured flow into a pressure difference signal, a differential pressure gauge that can convert this pressure difference into a corresponding flow value for display, and a display instrument.

[0003] In the Chinese patent with the publication number CN216206665U, a two-phase flowmeter based on double differential pressure is disclosed. This patent can accurately calculate the gas phase flow and liquid phase flow of the fluid in the flowmeter. However, in the two-phase flow metering device based on the double differential pressure principle of the above patent, the pressure taking method adopted is to open a pressure taking port on the side wall of the pipeline, and then transmit the pressure to the sensor through a pressure guiding pipeline. The pressure guiding pipeline is generally thin and long. This structure of the pressure taking method is not suitable for use in the oil and gas environment. When encountering slightly viscous oil, the pressure taking pipeline will be blocked, resulting in the device being unable to be used. Moreover, both differential pressure sensors are installed in the horizontal pipe section, only the throttling elements corresponding to the front and rear sensors are different. Although the corresponding gas-liquid flow can be calculated through a certain algorithm according to the two differential pressure values, this structure of the device generally adapts to the mixed-phase fluid with more gas and less liquid. When the liquid volume is large, the error increases significantly.

[0004] To solve the above problems, a double differential pressure type multiphase flow metering device is proposed in this application. Content of the Utility Model

[0005] To solve the problems raised in the above background technique. The utility model provides a double differential pressure type multiphase flow metering device, which has the characteristics of convenient maintenance, easy cleaning, and minimizing the system error under different gas-liquid flows.

[0006] To achieve the above object, the utility model provides the following technical solutions:

[0007] The double differential pressure type multiphase flow metering device includes:

[0008] Multiphase flow metering body, the multiphase flow metering body includes a water cut meter and a control box. A multiphase inlet pipe and a multiphase outlet pipe are provided on the water cut meter. A pressure transmitter and a wedge throttle element are provided on the multiphase inlet pipe. A temperature transmitter is provided on the multiphase outlet pipe. The two pressure tapping ports of the horizontal differential pressure transmitter are both installed on the inlet pipe, with the high-pressure end and the low-pressure end respectively in front of and behind the throttle element. The pressure tapping port of the vertical differential pressure transmitter is installed on the bypass pipeline of the water cut meter. The display parts of the two transmitters' heads are fixed on the outlet pipeline through brackets. Electrical components such as a touch screen, a switching power supply, a data acquisition module, and a communication module are provided in the control box. All instruments are powered by the control box and collect data. The touch screen in the control box serves as the data processing center of the system, collecting data from each instrument and calculating the oil, gas, and water flow rates of the measured mixed fluid through a program.

[0009] As an optimization of the double differential pressure type multiphase flow metering device of the present utility model, the first differential pressure transmitter includes a first pressure tapping pipe, a second pressure tapping pipe, and a first transmitter head. The first pressure tapping pipe and the second pressure tapping pipe are both arranged on the multiphase inlet pipe, and the first pressure tapping pipe and the second pressure tapping pipe are at both ends of the wedge throttle element. The first transmitter head is connected to the first pressure tapping pipe and the second pressure tapping pipe through pressure guiding pipes respectively. The first transmitter head is installed on the multiphase outlet pipe.

[0010] As an optimization of the double differential pressure type multiphase flow metering device of the present utility model, the first pressure tapping pipe and the second pressure tapping pipe are installed on the horizontal section of the multiphase inlet pipe. The first pressure tapping pipe is arranged at the high-pressure end, and the second pressure tapping pipe is arranged at the low-pressure end. The high-pressure end is in front, and the low-pressure end is behind. The first transmitter head is installed on the multiphase outlet pipe through a bracket, and the first transmitter head does not contact the medium to be tested. The pressure tapping ports of the first pressure tapping pipe and the second pressure tapping pipe use the inserted barrel type.

[0011] As an optimization of the double differential pressure type multiphase flow metering device of the present utility model, the second differential pressure transmitter includes a third pressure tapping pipe, a fourth pressure tapping pipe, and a second transmitter head. A vertical bypass pipeline is provided on the water cut meter. The third pressure tapping pipe and the fourth pressure tapping pipe are installed on the bypass pipeline, and the second transmitter head is connected to the third pressure tapping pipe and the fourth pressure tapping pipe through pressure guiding pipes respectively. The second transmitter head is installed on the multiphase outlet pipe.

[0012] As an optimization of the double differential pressure type multiphase flow metering device of the present utility model, the third pressure tapping pipe and the fourth pressure tapping pipe are both installed on the vertical pipe section of the bypass of the water cut meter. The third pressure tapping pipe is arranged at the high-pressure end, and the fourth pressure tapping pipe is arranged at the low-pressure end. The high-pressure end is below, and the low-pressure end is above. The second transmitter head is installed on the multiphase outlet pipe through a bracket, and the second transmitter head does not contact the medium to be tested. The pressure tapping ports of the third pressure tapping pipe and the fourth pressure tapping pipe use the inserted barrel type.

[0013] Preferably, for the dual differential pressure type multiphase flow metering device of the present utility model, flanges are provided on both the first pressure tapping pipe and the second pressure tapping pipe and the third pressure tapping pipe and the fourth pressure tapping pipe. One end of the flange is provided with a connecting pipe, and one end of the pressure guiding pipe is connected to one end of the connecting pipe.

[0014] Preferably, for the dual differential pressure type multiphase flow metering device of the present utility model, a measuring cylinder is provided on one side of the water content meter, and three-way valves are provided at both the inlet and the outlet of the water content meter.

[0015] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0016] 1. Through the cooperation of structures such as the first differential pressure transmitter, the water content meter, the second differential pressure transmitter, and the control box, the blockage of the pressure guiding pipe by heavy oil blocks can be effectively avoided. The connection between the pressure tapping port and the pipeline is a flange connection, which is convenient for maintenance. Even if the differential pressure transmitter cannot be used due to wax deposition or other situations, the pressure tapping end of the sensor can be easily removed for cleaning. This structural design is more suitable for the wellhead metering environment, and a set of coefficients is obtained through laboratory calibration, making the system error minimized under different gas-liquid flow rates.

[0017] 2. By installing the second differential pressure transmitter on the bypass pipeline of the water content meter, the product structure is more compact, the overall volume is smaller, and it is convenient for transportation and installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings are used to provide a further understanding of the present utility model, and constitute a part of the specification. Together with the embodiments of the present utility model, they are used to explain the present utility model, and do not constitute a limitation to the present utility model. In the drawings:

[0019] Figure 1 is the structural schematic diagram of the present utility model;

[0020] Figure 2 is for the present utility model Figure 1 is the structural schematic diagram of the first transmitter head in the present utility model;

[0021] Figure 3 is the installation schematic diagram of each instrument of the present utility model;

[0022] Figure 4 is the schematic diagram of an alternative solution for the instrument installation of the present utility model;

[0023] Figure 5 is one of the structural schematic diagrams of the two pressure tapping ports of the first differential pressure transmitter of the present utility model;

[0024] Figure 6 is the other structural schematic diagram of the two pressure tapping ports of the first differential pressure transmitter of the present utility model.

[0025] In the figure: 2, the first differential pressure transmitter; 3, the wedge-shaped throttling element; 4, the pressure transmitter; 5, the water content meter; 6, the second differential pressure transmitter; 7, the temperature transmitter; 9, the control box; 21, the first pressure tapping pipe; 22, the second pressure tapping pipe; 23, the first transmitter head; 61, the third pressure tapping pipe; 62, the fourth pressure tapping pipe; 63, the second transmitter head. Specific implementation mode

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0027] The present invention provides a Figures 1-6 double differential pressure type multiphase flow metering device as shown in

[0028] The double differential pressure type multiphase flow metering device includes:

[0029] The multiphase flow metering body, the multiphase flow metering body includes a water content meter 5 and a control box 9. A multiphase inlet pipe and a multiphase outlet pipe are arranged on the water content meter 5. A pressure transmitter 4 and a wedge-shaped throttling element 3 are arranged on the multiphase inlet pipe. A temperature transmitter 7 is arranged on the multiphase outlet pipe. A first differential pressure transmitter 2 and a second differential pressure transmitter 6 are also arranged on the water content meter 5. Electrical components such as a touch screen, a switching power supply, a data acquisition module, and a communication module are arranged in the control box 9. All instruments are powered by the control box 9 and collect data. The touch screen in the control box 9 serves as the data processing center of the system, collects the data of each instrument, and calculates the oil, gas, and water flow rates of the measured mixed fluid through a program. A measuring cylinder is arranged on one side of the water content meter 5, and three-way valves are arranged at both the inlet and outlet of the water content meter 5.

[0030] The first differential pressure transmitter 2 includes a first pressure tapping pipe 21, a second pressure tapping pipe 22, and a first transmitter head 23. The first pressure tapping pipe 21 and the second pressure tapping pipe 22 are both arranged on the multiphase inlet pipe, and the first pressure tapping pipe 21 and the second pressure tapping pipe 22 are at both ends of the wedge-shaped throttling element 3. The first transmitter head 23 is connected to the first pressure tapping pipe 21 and the second pressure tapping pipe 22 through pressure guiding pipes respectively, and the first transmitter head 23 is installed on the multiphase outlet pipe.

[0031] The second differential pressure transmitter 6 includes a third pressure tapping pipe 61, a fourth pressure tapping pipe 62 and a second transmitter head 63. A vertical bypass pipe is provided on the water content meter 5. The third pressure tapping pipe 61 and the fourth pressure tapping pipe 62 are installed on the bypass pipe, and the second transmitter head 63 is connected to both the third pressure tapping pipe 61 and the fourth pressure tapping pipe 62 through pressure guiding pipes. The second transmitter head 63 is installed on the multiphase outflow pipe; the third pressure tapping pipe 61 and the fourth pressure tapping pipe 62 are installed on the horizontal section of the multiphase outflow pipe. The third pressure tapping pipe 61 is arranged at the high-pressure end, and the fourth pressure tapping pipe 62 is arranged at the low-pressure end. The high-pressure end is at the lower part and the low-pressure end is at the upper part. The second transmitter head 63 is installed on the multiphase outflow pipe through a bracket, and the second transmitter head 63 does not contact the medium to be tested. The pressure tapping ports of the third pressure tapping pipe 61 and the fourth pressure tapping pipe 62 use an inserted barrel type.

[0032] Flanges are provided on both the first pressure tapping pipe 21 and the second pressure tapping pipe 22 and the third pressure tapping pipe 61 and the fourth pressure tapping pipe 62. One end of the flange is provided with a connecting pipe, and one end of the pressure guiding pipe is connected to one end of the connecting pipe.

[0033] By adopting the above technical solution:

[0034] During use, the mixed fluid flows from the inner wall of the multiphase inflow pipe, first passes through the first differential pressure transmitter 2, then passes through the pressure transmitter 4 after flowing through the wedge-shaped throttling element 3, and finally enters the interior of the water content meter 5. The mixed fluid entering the interior of the water content meter 5 passes through the measuring cylinder or through the bypass pipe. The mixed liquid inside the water content meter 5 then flows into the multiphase outflow pipe, and the mixed liquid inside the multiphase outflow pipe flows through the temperature transmitter 7 and then is discharged;

[0035] When it is necessary to sample the water content meter, the mixed fluid flows through the measuring cylinder. During other time periods, the mixed fluid flows through the bypass pipeline, and then the three-way valve of the water content meter 5 is controlled by the control box 9 to intake and discharge water, so as to sample the mixed liquid inside the water content meter 5. By using the inserted barrel type for the pressure tapping ports of the first pressure tapping pipe 21, the second pressure tapping pipe 22, the third pressure tapping pipe 61 and the fourth pressure tapping pipe 62, the thick oil block can be effectively prevented from blocking the pressure guiding pipe. The connection between the pressure tapping port and the pipeline is a flange connection, which is convenient for maintenance. Even if the differential pressure transmitter cannot be used due to wax deposition or other situations, the pressure tapping end of the sensor can be easily removed for cleaning. This structural design is more suitable for the wellhead metering environment.

[0036] In this embodiment, specifically when measuring the liquid, the measurement principle of a single differential pressure flowmeter can be simplified into the following formula:

[0037]

[0038] Wherein, Q vThe volumetric flow rate; k is a coefficient related to the throttling area, pipe diameter, etc., and a set of values can be obtained through calibration. ΔP is the differential pressure value before and after the throttling element; ρ is the density of the measured medium. This formula is the formula for volumetric flow rate, and the relationship between mass and volume is as follows:

[0039] m = V * ρ

[0040] Therefore, we can obtain the mass flow rate formula:

[0041]

[0042] Among them, ΔP is measured by the differential pressure transmitter A. ρ can be obtained by combining the differential pressure value measured by the differential pressure transmitter B with the liquid pressure formula:

[0043] ΔP = ρ · g · h

[0044] Among them, ΔP is the differential pressure value measured by the differential pressure transmitter B, ρ is the density of the mixed medium, g is the gravitational acceleration constant, and h is the height difference constant between the high and low pressure ends of the differential pressure transmitter. Rearranging the above formula, the following formula can be obtained:

[0045]

[0046] ΔP 1 ·ΔP 2 are the values measured by the horizontal and vertical differential pressure transmitters respectively. And g and h are both constants and can be combined with k. Thus, the above formula can be simplified to:

[0047]

[0048] Therefore, through the values of the two differential pressure transmitters and the coefficient k, the mass flow rate of the mixed medium can be calculated. And the mass proportion of gas in the gas-liquid mixed-phase fluid is extremely small, so the mass flow rate of the mixed-phase fluid is approximately equal to the liquid flow rate. And the coefficient K can be obtained through laboratory calibration. After obtaining the liquid flow rate, combined with the water content data given by the water cut meter 5, the oil volume and water volume can be obtained.

[0049] In addition, in this embodiment, specifically when measuring gas, for the mixed-phase fluid, there is the following formula:

[0050] m 液 +m 气 =m 混

[0051] V 液 +V 气 =V 混

[0052] m 液 =V 液 ·ρ 液

[0053] m 气 ≈0

[0054] Rearranging the above equations, we get:

[0055]

[0056] V in the above 气 is the gas volume under the operating conditions. To calculate the gas volume under the operating conditions, temperature and pressure compensation also needs to be added:

[0057]

[0058] where m 混 is the mass flow rate of the mixed fluid, ρ 混 is the density of the mixed medium, which can be calculated from the differential pressure value measured by the differential pressure transmitter B and has been described previously. ρ 液 is the liquid density, or the density of the oil-water mixture. If the water cut of an oil well changes little over a period of time, then the change in ρ 液 will be even smaller and can be used as a settable parameter and input into the system. If the water cut of the produced fluid from an oil well changes significantly, it can be calculated from the mass percentage of the water cut, and the calculation process is as follows:

[0059] The following relationship exists for the mass of the mixed liquid:

[0060] m 液 = m 油 + m 水

[0061] m 水 = δ·m 液

[0062] V 液 = V 油 + V 水

[0063] m 液 = V 液 ·ρ 液

[0064] m 液 = V 液 ·ρ 液

[0065] m 水 = V 水 ·ρ 水

[0066] where δ represents the mass percentage of the water cut. According to the above formulas, after rearrangement, we get:

[0067]

[0068] where ρ 油 and ρ 水 are the density of oil and the density of water in the produced fluid of the oil well, respectively. For a quite long period, these two values change very little and can be input into the system as parameters.

[0069] In addition, as shown in Figures 5-6 the first pressure tapping pipe 21 and the second pressure tapping pipe 22 are installed on the horizontal section of the multiphase inflow pipe. The first pressure tapping pipe 21 is arranged at the high-pressure end, and the second pressure tapping pipe 22 is arranged at the low-pressure end, with the high-pressure end in the front and the low-pressure end at the back. The first transmitter head 23 is installed on the multiphase outflow pipe through a bracket, and the first transmitter head 23 does not contact the medium to be tested. The pressure tapping ports of the first pressure tapping pipe 21 and the second pressure tapping pipe 22 use the inserted barrel type.

[0070] By adopting the above technical solution:

[0071] During use, the second differential pressure transmitter 6 can be installed on other vertical pipes. After the mixed liquid passes through the multiphase inflow pipe, it first passes through the first differential pressure transmitter 2, then through the wedge-shaped throttling element 3, then through the pressure transmitter 4, and then through the second differential pressure transmitter 6 before entering the interior of the water cut meter 5, so that the mixed liquid first flows through the first differential pressure transmitter 2 and the second differential pressure transmitter 6 and then enters the water cut meter 5. The first pressure tapping pipe 21 and the second pressure tapping pipe 22 can be arranged on the side of the multiphase inflow pipe, or can be installed above and below the multiphase inflow pipe, which is convenient for people to install according to the actual situation, greatly improving the practicability of the device.

[0072] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. Double differential pressure multiphase flow metering device, characterized in that: include: A multiphase flow metering body, the multiphase flow metering body comprising a water content meter (5) and a control box (9), the water content meter (5) being provided with a multiphase inlet pipe and a multiphase outlet pipe, the multiphase inlet pipe being provided with a pressure transmitter (4) and a wedge-shaped throttling piece (3), the multiphase outlet pipe being provided with a temperature transmitter (7), and the water content meter (5) being further provided with a first differential pressure transmitter (2) and a second differential pressure transmitter (6).

2. The dual differential pressure multiphase flow metering device according to claim 1, characterized in that: The first differential pressure transmitter (2) comprises a first pressure-taking tube (21), a second pressure-taking tube (22) and a first transmitter head (23); the first pressure-taking tube (21) and the second pressure-taking tube (22) are both arranged on the multiphase inlet tube, and the first pressure-taking tube (21) and the second pressure-taking tube (22) are located at two ends of a wedge-shaped throttling member (3); the first transmitter head (23) is connected to the first pressure-taking tube (21) and the second pressure-taking tube (22) via a pressure-conducting tube; and the first transmitter head (23) is installed on the multiphase outlet tube.

3. The dual differential pressure multiphase flow metering device according to claim 2, characterized in that: The first pressure-taking pipe (21) and the second pressure-taking pipe (22) are installed on the horizontal section of the multiphase inflow pipe, the first pressure-taking pipe (21) is arranged at the high-pressure end, and the second pressure-taking pipe (22) is arranged at the low-pressure end.

4. The dual differential pressure multiphase flow metering device according to claim 2, characterized in that: The second differential pressure transmitter (6) comprises a third pressure-taking tube (61), a fourth pressure-taking tube (62) and a second transmitter head (63); a vertical bypass pipe is provided on the water content meter (5); the third pressure-taking tube (61) and the fourth pressure-taking tube (62) are installed on the bypass pipe; the second transmitter head (63) is connected to the third pressure-taking tube (61) and the fourth pressure-taking tube (62) via a pressure-conducting tube; and the second transmitter head (63) is installed on the multiphase outflow pipe.

5. The dual differential pressure multiphase flow metering device according to claim 4, characterized in that: The third pressure-taking pipe (61) and the fourth pressure-taking pipe (62) are both installed on the bypass vertical pipe section of the water content meter (5), the third pressure-taking pipe (61) is arranged at the high-pressure end, and the fourth pressure-taking pipe (62) is arranged at the low-pressure end.

6. The dual differential pressure multiphase flow metering device according to claim 4, characterized in that: The first pressure-taking tube (21), the second pressure-taking tube (22), the third pressure-taking tube (61) and the fourth pressure-taking tube (62) are all provided with flanges, one end of the flange is provided with a connecting tube, and one end of the pressure-conducting tube is connected to one end of the connecting tube.

7. The dual differential pressure multiphase flow metering device according to claim 1, characterized in that: A measuring cylinder is provided on one side of the water content meter (5), and three-way valves are provided at the inlet and outlet of the water content meter (5).

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