Offshore platform multiphase flowmeter

Abstract

The invention provides a multiphase flowmeter for an offshore platform. The multiphase flowmeter comprises a multiphase flowmeter system, a gas sampling system, a carbon dioxide detection system and a data acquisition and processing unit. The multiphase flowmeter system measures the total flow, the gas content and the water content of fluid, and the data collecting and processing unit receives the data and outputs the flow of oil, water and gas in the fluid. The gas sampling system is used for exporting a gas sample from the multiphase flowmeter system and supplying the gas sample to the carbon dioxide detection system, the carbon dioxide detection system performs carbon dioxide concentration detection, and the data acquisition and processing unit outputs the carbon dioxide concentration in a gas phase according to received data. According to the multiphase flow meter of the offshore platform, gas in fluid can be obtained in a bypass sampling mode, the concentration of carbon dioxide in produced gas is accurately measured through the carbon dioxide detection system, and the effect of integrated online measurement of the oil flow, the water flow, the gas flow and the carbon dioxide concentration is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of multiphase flow measurement on offshore platforms, and in particular to a multiphase flow meter on offshore platforms. Background Art

[0002] At present, offshore platforms usually use multiphase flow meters to measure wellhead flow, mainly through the "Venturi + ray" technology, to measure the three-phase flow of oil, water and gas at the wellhead online.

[0003] According to the development needs of offshore oil and gas fields, it is necessary to detect the concentration of carbon dioxide while testing the flow rates of different oil wells. However, traditional carbon dioxide sensors usually use absorption, pressure swing adsorption or low-temperature distillation methods for measurement, which are easily interfered by other components in a multiphase fluid environment, resulting in inaccurate measurement of carbon dioxide content and unable to meet the detection needs of oil reservoirs and processes. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides an offshore platform multiphase flowmeter, which aims to solve the problem in the related art that the carbon dioxide concentration cannot be accurately detected when measuring the inlet flow.

[0005] The present invention provides a multiphase flow meter, comprising:

[0006] A multiphase flow meter system, the multiphase flow meter system comprising a first fluid inlet, a first gas phase outlet and a first liquid phase outlet, the first fluid inlet being used to connect to a wellhead, the first gas phase outlet and the first liquid phase outlet being used to connect to a main pipeline, the multiphase flow meter system being used to detect a total flow rate, a gas content and a water content of a fluid;

[0007] A gas sampling system, the gas sampling system comprising a first gas phase inlet, a second gas phase outlet and a third liquid phase outlet, the first gas phase inlet being connected to the first gas phase outlet of the multiphase flow meter system, and the third liquid phase outlet being used to be connected to the main line;

[0008] A carbon dioxide detection system, the carbon dioxide detection system comprising a second gas phase inlet and a fourth gas phase outlet, the second gas phase inlet is connected to the second gas phase outlet of the gas sampling system, the fourth gas phase outlet is used to connect to a torch, and the carbon dioxide detection system is used to detect the carbon dioxide concentration in the gas;

[0009] A data acquisition and processing unit, the data acquisition and processing unit is used to communicate with the multiphase flowmeter system and the carbon dioxide detection system, and is used to output the flow rates of oil, water and gas in the fluid and the carbon dioxide concentration according to the total flow rate, gas content, water content and carbon dioxide concentration information of the fluid. According to the offshore platform multiphase flowmeter provided by the present invention, the carbon dioxide detection system includes an infrared measuring device.

[0010] According to the offshore platform multiphase flowmeter provided by the present invention, the multiphase flowmeter system comprises:

[0011] A single-energy gamma sensor, wherein the first fluid inlet is arranged at an upstream end of the single-energy gamma sensor, the single-energy gamma sensor is communicatively connected with the data acquisition and processing unit, and the single-energy gamma sensor is used to measure the gas content in the fluid;

[0012] A venturi flowmeter, wherein the upstream end of the venturi flowmeter is connected to the downstream end of the single-energy gamma sensor, and the venturi flowmeter is used to measure the total flow of the fluid;

[0013] A flow pattern regulator, wherein the first gas phase outlet is arranged on the flow pattern regulator, and the flow pattern regulator is also provided with a second fluid inlet and a second liquid phase outlet, wherein the second fluid inlet is connected to the downstream end of the venturi flowmeter, and the flow pattern regulator is used to separate gas and liquid from the fluid and mix oil and water;

[0014] A dual-energy gamma sensor, wherein the first liquid phase outlet is arranged at the downstream end of the dual-energy gamma sensor, the upstream end of the dual-energy gamma sensor is connected to the second liquid phase outlet of the flow pattern regulator, the dual-energy gamma sensor is communicatively connected to the data acquisition and processing unit, and the dual-energy gamma sensor is used to measure the water content in the fluid.

[0015] According to the offshore platform multiphase flowmeter provided by the present invention, the gas sampling system comprises:

[0016] A gas sampler, wherein the first gas phase inlet, the second gas phase outlet, the third gas phase outlet and the third liquid phase outlet are all arranged on the gas sampler, and the gas sampler is used to separate the fluid into gas and liquid and dry the gas phase;

[0017] A sample gas inlet pipeline, wherein the sample gas inlet pipeline is arranged between the first gas phase inlet of the gas sampler and the first gas phase outlet of the flow pattern adjuster;

[0018] a decompression pipeline, the decompression pipeline being arranged between the second gas phase outlet of the gas sampler and the second gas phase inlet of the carbon dioxide detection system;

[0019] A liquid discharge pipeline is provided between the third liquid phase outlet of the gas sampler and the main line.

[0020] According to the offshore platform multiphase flowmeter provided by the present invention, the gas sampling system further comprises a residual gas exhaust pipeline, and the residual gas exhaust pipeline is arranged between the third gas phase outlet of the gas sampler and the main pipeline.

[0021] According to the offshore platform multiphase flowmeter provided by the present invention, the gas sampler is also provided with a temperature transmitter, a first pressure transmitter and a liquid level transmitter.

[0022] According to the offshore platform multiphase flowmeter provided by the present invention, a first one-way valve and a first on-off valve are connected in series on the sample gas inlet pipeline, the first one-way valve is arranged at the upstream end of the first on-off valve, and the conduction direction of the first one-way valve is from the flow type regulator to the gas sampler.

[0023] According to the offshore platform multiphase flowmeter provided by the present invention, a second one-way valve and a second on-off valve are connected in series on the liquid discharge pipeline, the second one-way valve is arranged at the downstream end of the second on-off valve, and the conduction direction of the second one-way valve is from the gas sampler to the main line.

[0024] According to the offshore platform multiphase flowmeter provided by the present invention, a second pressure transmitter and at least one electric pressure reducing valve are connected in series on the pressure reducing pipeline, and the second pressure transmitter is electrically connected to the electric pressure reducing valve.

[0025] According to the offshore platform multiphase flowmeter provided by the present invention, a third one-way valve is connected in series on the residual gas discharge pipeline, and the conduction direction of the third one-way valve is from the gas sampler to the main pipeline.

[0026] The present invention adopts the above technical solution, which has the following advantages:

[0027] The offshore platform multiphase flowmeter provided by the present invention comprises a multiphase flowmeter system, a gas sampling system, a carbon dioxide detection system and a data acquisition and processing unit. The multiphase flowmeter system comprises a first fluid inlet, a first gas phase outlet and a first liquid phase outlet, the first fluid inlet is used to connect to the wellhead, the first gas phase outlet and the first liquid phase outlet are used to connect to the main pipeline, and the data acquisition and processing unit is connected to the multiphase flowmeter system in communication. The fluid discharged from the wellhead enters the multiphase flowmeter system through the first fluid inlet. When flowing through the multiphase flowmeter system, the multiphase flowmeter system separates the fluid into gas and liquid, and detects the total flow rate, gas content and water content of the fluid. The data acquisition and processing unit receives the above data and outputs the flow rate of oil, water and gas in the fluid. The gas sampling system comprises a first gas phase inlet, a second gas phase outlet and a third liquid phase outlet, the first gas phase inlet is connected to the first gas phase outlet of the multiphase flowmeter system, and the third liquid phase outlet is used to connect to the main pipeline. The carbon dioxide detection system includes a second gas phase inlet and a fourth gas phase outlet, the second gas phase inlet is connected to the second gas phase outlet of the gas sampling system, the fourth gas phase outlet is used to connect to the torch, and the data acquisition and processing unit is connected to the carbon dioxide detection system. Part of the gas at the first gas phase outlet of the multiphase flowmeter system enters the gas sampling system through the first gas phase inlet of the gas sampling system, the gas sampling system quickly separates the gas and liquid into the fluid entering, and dries the gas phase, the gas phase enters the carbon dioxide detection system through the second gas phase outlet and the second gas phase inlet to detect the carbon dioxide concentration, and the data acquisition and processing unit outputs the carbon dioxide concentration in the gas phase according to the received data. The liquid phase separated in the gas sampling system enters the main pipeline through the third liquid phase outlet. The offshore platform multiphase flowmeter provided by the present invention can obtain the gas in the fluid by bypass sampling, and accurately measure the concentration of carbon dioxide in the produced gas through the carbon dioxide detection system, so as to achieve the effect of integrated online measurement of oil, water, gas flow and carbon dioxide concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 It is a flow chart of a multiphase flow meter for an offshore platform provided in one embodiment of the present invention.

[0030] Reference numerals:

[0031] 100: wellhead; 210: single-energy gamma sensor; 211: first fluid inlet; 220: venturi flowmeter; 230: flow pattern regulator; 231: second fluid inlet; 232: first gas phase outlet; 233: second liquid phase outlet; 240: dual-energy gamma sensor; 241: first liquid phase outlet; 310: gas sampler; 311: first gas phase inlet; 312: second gas phase outlet; 313: third gas phase outlet; 314: third liquid phase outlet; 320: sample gas inlet pipeline ; 321: first one-way valve; 322: first on-off valve; 330: pressure reducing pipeline; 331: electric pressure reducing valve; 332: pressure reducing valve; 333: second pressure transmitter; 340: liquid discharge pipeline; 341: second on-off valve; 342: second one-way valve 350: residual gas discharge pipeline; 351: third one-way valve; 360: temperature transmitter; 370: first pressure transmitter; 380: liquid level transmitter; 400: carbon dioxide detection system; 500: data acquisition and processing unit. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0034] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0035] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0037] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0038] The offshore platform multiphase flowmeter provided by the present invention comprises a multiphase flowmeter system, a gas sampling system, a carbon dioxide detection system and a data acquisition and processing unit. The multiphase flowmeter system comprises a first fluid inlet, a first gas phase outlet and a first liquid phase outlet, the first fluid inlet is used to connect to the wellhead, the first gas phase outlet and the first liquid phase outlet are used to connect to the main pipeline, and the data acquisition and processing unit is connected to the multiphase flowmeter system in communication. The fluid discharged from the wellhead enters the multiphase flowmeter system through the first fluid inlet. When flowing through the multiphase flowmeter system, the multiphase flowmeter system separates the fluid into gas and liquid, and detects the total flow rate, gas content and water content of the fluid. The data acquisition and processing unit receives the above data and outputs the flow rate of oil, water and gas in the fluid. The gas sampling system comprises a first gas phase inlet, a second gas phase outlet and a third liquid phase outlet, the first gas phase inlet is connected to the first gas phase outlet of the multiphase flowmeter system, and the third liquid phase outlet is used to connect to the main pipeline. The carbon dioxide detection system includes a second gas phase inlet and a fourth gas phase outlet, the second gas phase inlet is connected to the second gas phase outlet of the gas sampling system, the fourth gas phase outlet is used to connect to the torch, and the data acquisition and processing unit is connected to the carbon dioxide detection system. Part of the gas at the first gas phase outlet of the multiphase flowmeter system enters the gas sampling system through the first gas phase inlet of the gas sampling system, the gas sampling system quickly separates the gas and liquid into the fluid material entering, and dries the gas phase, the gas phase enters the carbon dioxide detection system through the second gas phase outlet and the second gas phase inlet to detect the carbon dioxide concentration, and the data acquisition and processing unit outputs the carbon dioxide concentration in the gas phase according to the received data. The liquid phase separated in the gas sampling system enters the main pipeline through the third liquid phase outlet. The offshore platform multiphase flowmeter provided by the present invention can obtain the gas in the fluid by bypass sampling, and accurately measure the concentration of carbon dioxide in the produced gas through the carbon dioxide detection system, so as to achieve the effect of integrated online measurement of oil, water, gas flow and carbon dioxide concentration.

[0039] Combine the following Figure 1 An offshore platform multiphase flow meter of the present invention is described.

[0040] The offshore platform multiphase flowmeter provided by the present invention comprises a multiphase flowmeter system, a gas sampling system, a carbon dioxide detection system 400 and a data acquisition and processing unit 500 .

[0041] The multiphase flow meter system includes a first fluid inlet 211, a first gas phase outlet 232 and a first liquid phase outlet 241. The first fluid inlet 211 is used to connect to the wellhead 100, the first gas phase outlet 232 and the first liquid phase outlet 241 are used to connect to the main pipeline, and the data acquisition and processing unit 500 is communicatively connected to the multiphase flow meter system.

[0042] The fluid discharged from the wellhead 100 enters the multiphase flow meter system through the first fluid inlet 211. When flowing through the multiphase flow meter system, the multiphase flow meter system separates the fluid into gas and liquid. The gas phase enters the main line through the first gas phase outlet 232, and the liquid phase enters the main line through the first liquid phase outlet 241. When the fluid flows through the multiphase flow meter system, the multiphase flow meter system measures the total flow rate, gas content and water content of the fluid. The data acquisition and processing unit 500 receives the above data and outputs the flow rates of oil, water and gas in the fluid.

[0043] The gas sampling system includes a first gas phase inlet 311 , a second gas phase outlet 312 and a third liquid phase outlet 314 . The first gas phase inlet 311 is connected to the first gas phase outlet 232 of the multiphase flow meter system, and the third liquid phase outlet 314 is used to connect to the main line.

[0044] The carbon dioxide detection system 400 includes a second gas phase inlet 410 and a fourth gas phase outlet 420 . The second gas phase inlet 410 is connected to the second gas phase outlet 312 of the gas sampling system. The fourth gas phase outlet 420 is used to connect to the torch. The data acquisition and processing unit 500 is in communication connection with the carbon dioxide detection system 400 .

[0045] Part of the gas phase fluid flowing out of the multiphase flowmeter system enters the gas sampling system through the first gas phase outlet 232 and the first gas phase inlet 311. The gas sampling system quickly separates the gas phase fluid entering therein into gas and liquid, and quickly dries the gas phase therein. The gas phase separated in the gas sampling system enters the carbon dioxide detection system 400 through the second gas phase outlet 312 and the second gas phase inlet 410 to measure the carbon dioxide concentration. The data acquisition and processing unit 500 outputs the carbon dioxide concentration in the fluid according to the received data. The liquid phase separated in the gas sampling system enters the main line through the third liquid phase outlet 314.

[0046] The offshore platform multiphase flowmeter provided by the present invention can obtain gas in the fluid by bypass sampling, and accurately measure the concentration of carbon dioxide in the produced gas through the carbon dioxide detection system 400, thereby achieving the effect of integrated online measurement of oil, water, gas flow and carbon dioxide concentration.

[0047] In some embodiments, carbon dioxide detection system 400 includes an infrared measurement device.

[0048] Specifically, the carbon dioxide detection system 400 is based on the infrared measurement principle to achieve accurate measurement of carbon dioxide concentration. Different gases have different absorption characteristics for infrared light of a specific wavelength, that is, each gas will absorb to different degrees at a specific wavelength. This phenomenon is based on the transition of the vibration and rotation energy levels of gas molecules. Carbon dioxide strongly absorbs infrared light with a wavelength of 4.26 microns. By measuring the absorption of infrared light in the gas, the concentration of the gas can be determined based on the Lambert-Beer law.

[0049] In some embodiments, the multiphase flow meter system includes a single energy gamma sensor 210 , a venturi flow meter 220 , a flow pattern conditioner 230 , and a dual energy gamma sensor 240 .

[0050] The first fluid inlet 211 of the multiphase flow meter system is disposed at the upstream end of the single-energy gamma sensor 210 . The single-energy gamma sensor 210 is in communication with the data acquisition and processing unit 500 . The single-energy gamma sensor 210 is used to measure the gas content in the fluid.

[0051] The fluid flowing out of the wellhead 100 is a multiphase flow. The multiphase flow first passes through the single-energy gamma sensor 210. When the gamma rays pass through the multiphase flow mixture flowing through the pipeline, the receiving intensity will be weakened due to the absorption of the medium. Different components of the multiphase flow have different attenuations. Based on this principle, the gas content of the fluid can be measured.

[0052] The upstream end of the venturi flowmeter 220 is connected to the downstream end of the single-energy gamma sensor 210 , and the venturi flowmeter 220 is used to measure the total flow of the fluid.

[0053] The fluid passing through the single-energy gamma sensor 210 enters the venturi flowmeter 220 , and the venturi flowmeter 220 can measure the total flow of the multiphase flow based on the differential pressure.

[0054] The first gas phase outlet 232 is arranged on the flow pattern regulator 230, and the flow pattern regulator 230 is also provided with a second fluid inlet 231 and a second liquid phase outlet 233. The second fluid inlet 231 is connected to the downstream end of the venturi flowmeter 220. The flow pattern regulator 230 is used to separate the gas and liquid of the fluid and mix oil and water.

[0055] The multiphase flow passing through the venturi flowmeter 220 enters the flow pattern adjuster 230 through the second fluid inlet 231. The flow pattern adjuster 230 partially separates the gas in the multiphase flow and mixes the oil and water phases, thereby reducing the gas content of the fluid, thereby ensuring the accuracy of the dual-energy gamma sensor 240 in measuring the water content. The separated gas phase can be discharged through the first gas phase outlet 232. The discharged gas phase can all enter the main pipeline, or part of the gas phase can be diverted into the gas sampling system when the carbon dioxide concentration needs to be detected.

[0056] The first liquid phase outlet 241 is disposed at the downstream end of the dual-energy gamma sensor 240 . The upstream end of the dual-energy gamma sensor 240 is connected to the second liquid phase outlet 233 of the flow pattern regulator 230 . The dual-energy gamma sensor 240 is in communication with the data acquisition and processing unit 500 .

[0057] The multiphase flow of the separated part of the gas discharged through the second liquid phase outlet 233 of the flow pattern adjuster 230 enters the dual-energy gamma sensor 240. Based on the principle that different media have different absorption rates of gamma rays, the water content in the multiphase flow can be measured. The measured fluid flows back to the main line through the first liquid phase outlet 241.

[0058] The data acquisition and processing unit 500 measures the total flow of the three-phase flow through the Venturi flowmeter 220, the gas content measured by the single-energy gamma sensor 210, and the water content measured by the dual-energy gamma sensor 240. After combining temperature and pressure compensation, the oil flow, gas flow and water flow of the three-phase flow are calculated according to a certain formula.

[0059] In some embodiments, the gas sampling system includes a gas sampler 310 , a sample gas inlet line 320 , a pressure reducing line 330 , and a liquid exhaust line 340 .

[0060] The first gas phase inlet 311 , the second gas phase outlet 312 and the third liquid phase outlet 314 are all arranged on the gas sampler 310 . The gas sampler 310 is used to separate the fluid into gas and liquid and dry the gas phase.

[0061] The gas sampler 310 is used as a bypass device to sample through the first gas phase outlet 232. The gas sampler 310 performs rapid gas-liquid separation and gas drying on the mixed gas sample to obtain the sampled gas. The gas sampler 310 is provided with a replaceable drying device to ensure the rapidity and accuracy of the carbon dioxide concentration measurement.

[0062] The separated gas enters the carbon dioxide detection system 400 through the second gas phase outlet 312 for carbon dioxide concentration detection, and the separated liquid flows back into the main line through the third liquid phase outlet 314 .

[0063] The sample gas inlet pipeline 320 is disposed between the first gas phase inlet 311 of the gas sampler 310 and the first gas phase outlet 232 of the flow pattern adjuster, and is used to introduce part of the gas flowing out of the first gas phase outlet 232 of the flow pattern adjuster 230 into the gas sampler 310 .

[0064] The decompression line 330 is disposed between the second gas phase outlet 312 of the gas sampler 310 and the second gas phase inlet 410 of the carbon dioxide detection system 400 .

[0065] The decompression pipeline 330 is used to decompress the gas discharged from the second gas phase outlet 312 and then transport it to the carbon dioxide detection system 400 to measure the carbon dioxide concentration.

[0066] The liquid discharge line 340 is disposed between the third liquid phase outlet 314 of the gas sampler 310 and the main line.

[0067] The liquid separated by the gas sampler 310 enters the main line through the liquid discharge line 340 .

[0068] In some embodiments, the gas sampling system further includes a residual gas exhaust pipeline 350 . The gas sampler 310 is provided with a third gas phase outlet 313 . The residual gas exhaust pipeline 350 is connected between the third gas phase outlet 313 and the main pipeline.

[0069] The gas separated from the gas sampler 310 partially enters the carbon dioxide detection system 400 through the pressure reducing pipeline 330 , and the remaining gas enters the main pipeline through the residual gas exhaust pipeline 350 .

[0070] In some embodiments, the gas sampler 310 is further provided with a temperature transmitter 360 , a first pressure transmitter 370 , and a liquid level transmitter 380 .

[0071] The temperature transmitter 360 is used to measure the fluid temperature, the pressure transmitter 370 is used to measure the fluid pressure, and the liquid level transmitter 380 monitors the height of the liquid level in the gas sampler 310 .

[0072] In some embodiments, a first one-way valve 321 and a first on-off valve 322 are connected in series on the sample gas inlet pipeline 320 , the first one-way valve 321 is arranged at the upstream end of the first on-off valve 322 , and the conduction direction of the first one-way valve 321 is from the flow type regulator 230 to the gas sampler 310 .

[0073] The mixed gas at the first gas phase outlet 232 of the flow type regulator 230 flows through the first one-way valve 321 and the first on-off valve 322 and then enters the gas sampler 310. The first one-way valve 321 can control the direction of fluid flow, and the first on-off valve 322 can be a solenoid valve for controlling the opening and closing of the pipeline.

[0074] In some embodiments, a second one-way valve 342 and a second on-off valve 341 are connected in series on the liquid discharge pipeline 340, the second one-way valve 342 is arranged at the downstream end of the second on-off valve 341, and the conduction direction of the second one-way valve 342 is from the gas sampler 310 to the main pipeline.

[0075] The fluid separated in the gas sampler 310 flows back to the main pipeline through the second one-way valve 342 and the second on-off valve 341. The second one-way valve 342 can control the flow direction of the fluid, and the second on-off valve 341 can be a solenoid valve for controlling the opening and closing of the pipeline.

[0076] In some embodiments, a second pressure transmitter 333 and at least one electric pressure reducing valve 331 are connected in series on the pressure reducing pipeline 330 , and the second pressure transmitter 333 is in communication connection with the electric pressure reducing valve 331 .

[0077] Specifically, the electric pressure reducing valve 331, the pressure reducing valve 332 and the second pressure transmitter 333 are connected in series on the pressure reducing pipeline 330 from upstream to downstream. The electric pressure reducing valve 331 and the pressure reducing valve 332 can adjust and reduce the outlet pressure. The small amount of mixed gas after separation and drying enters the carbon dioxide detection system 400 for carbon dioxide concentration detection after multi-stage pressure reduction.

[0078] The electric pressure reducing valve 331 can automatically control the outlet pressure according to the pressure value detected by the second pressure transmitter 333 .

[0079] In some embodiments, a third one-way valve 351 is connected in series to the residual gas exhaust pipeline 350 . The conduction direction of the third one-way valve 351 is from the gas sampler 310 to the main pipeline. The third one-way valve 351 is used to control the flow direction of the fluid.

[0080] The offshore platform multiphase flowmeter provided by the present invention adopts the technical solution of multiphase flowmeter + carbon dioxide detection system to achieve the effect of integrated online measurement of oil, water, gas flow and carbon dioxide concentration. The flow type regulator 230 partially separates the gas in the three-phase fluid, and then obtains the sampled gas after gas-liquid separation and gas drying through the gas sampler 310, which ensures the rapidity and accuracy of carbon dioxide concentration measurement.

[0081] The offshore platform multiphase flowmeter provided by the present invention has a compact structure, is easy to install, has a small size and is light in weight.

[0082] The offshore platform multiphase flowmeter provided by the present invention realizes online real-time monitoring of single well oil, water, gas flow and carbon dioxide concentration, improves the automation level of the offshore platform, and provides accurate and reliable data for prediction and early warning analysis of oil reservoirs, processes, etc.

[0083] The offshore platform multiphase flowmeter provided by the present invention reduces the frequency of on-site manual testing by personnel and reduces the on-site workload of personnel.

[0084] The offshore platform multiphase flowmeter provided by the present invention can be subsequently expanded to measure hydrogen sulfide concentration, etc. according to demand, and has promotion and application value.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. An offshore platform multiphase flow meter, characterized in that: include: A multiphase flow meter system, the multiphase flow meter system comprising a first fluid inlet (211), a first gas phase outlet (232) and a first liquid phase outlet (241), the first fluid inlet (211) being used to connect to a wellhead (100), the first gas phase outlet (232) and the first liquid phase outlet (241) being used to connect to a main pipeline, the multiphase flow meter system being used to detect a total flow rate, a gas content and a water content of a fluid; A gas sampling system, the gas sampling system comprising a first gas phase inlet (311), a second gas phase outlet (312) and a third liquid phase outlet (314), the first gas phase inlet (311) being connected to the first gas phase outlet (232) of the multiphase flow meter system, and the third liquid phase outlet (314) being used to be connected to the main line; A carbon dioxide detection system (400), the carbon dioxide detection system (400) comprising a second gas phase inlet (410) and a fourth gas phase outlet (420), the second gas phase inlet (410) being connected to the second gas phase outlet (312) of the gas sampling system, the fourth gas phase outlet (420) being used to be connected to a torch, the carbon dioxide detection system (400) being used to detect the carbon dioxide concentration in the gas; A data acquisition and processing unit (500) is used to communicate with the multiphase flow meter system and the carbon dioxide detection system (400), and is used to output the flow rates of oil, water and gas in the fluid and the carbon dioxide concentration according to the total flow rate, gas content, water content and carbon dioxide concentration information of the fluid.

2. The offshore platform multiphase flowmeter according to claim 1, characterized in that: The carbon dioxide detection system (400) comprises an infrared measuring device.

3. The offshore platform multiphase flow meter according to claim 1, characterized in that: The multiphase flow meter system comprises: A single-energy gamma sensor (210), wherein the first fluid inlet (211) is arranged at an upstream end of the single-energy gamma sensor (210), the single-energy gamma sensor (210) is communicatively connected to the data acquisition and processing unit (500), and the single-energy gamma sensor (210) is used to measure the gas content in the fluid; a venturi flowmeter (220), wherein the upstream end of the venturi flowmeter (220) is connected to the downstream end of the single-energy gamma sensor (210), and the venturi flowmeter (220) is used to measure the total flow of the fluid; A flow pattern regulator (230), wherein the first gas phase outlet (232) is arranged on the flow pattern regulator (230), and the flow pattern regulator (230) is also provided with a second fluid inlet (231) and a second liquid phase outlet (233), wherein the second fluid inlet (231) is connected to the downstream end of the venturi flowmeter (220), and the flow pattern regulator (230) is used to separate gas from liquid and to mix oil and water on the fluid; A dual-energy gamma sensor (240), wherein the first liquid phase outlet (241) is arranged at the downstream end of the dual-energy gamma sensor (240), the upstream end of the dual-energy gamma sensor (240) is connected to the second liquid phase outlet (233) of the flow pattern regulator (230), the dual-energy gamma sensor (240) is communicatively connected to the data acquisition and processing unit (500), and the dual-energy gamma sensor (240) is used to measure the water content in the fluid.

4. The offshore platform multiphase flow meter according to claim 3, characterized in that: The gas sampling system comprises: A gas sampler (310), wherein the first gas phase inlet (311), the second gas phase outlet (312) and the third liquid phase outlet (314) are all arranged on the gas sampler (310), and the gas sampler (310) is used to separate gas from liquid in the fluid and dry the gas phase; a sample gas inlet pipeline (320), wherein the sample gas inlet pipeline (320) is arranged between the first gas phase inlet (311) of the gas sampler (310) and the first gas phase outlet (232) of the flow pattern adjuster (230); a decompression pipeline (330), wherein the decompression pipeline (330) is arranged between the second gas phase outlet (312) of the gas sampler (310) and the second gas phase inlet (410) of the carbon dioxide detection system (400); A liquid discharge pipeline (340), wherein the liquid discharge pipeline (340) is arranged between the third liquid phase outlet (314) of the gas sampler (310) and the main pipeline.

5. The offshore platform multiphase flow meter according to claim 4, characterized in that: The gas sampling system further comprises a residual gas exhaust pipeline (350), and the gas sampler (310) is further provided with a third gas phase outlet (313), and the residual gas exhaust pipeline (350) is arranged between the third gas phase outlet (313) of the gas sampler (310) and the main pipeline.

6. The offshore platform multiphase flow meter according to claim 4, characterized in that: The gas sampler (310) is also provided with a temperature transmitter (360), a first pressure transmitter (370) and a liquid level transmitter (380).

7. The offshore platform multiphase flow meter according to claim 4, characterized in that: A first one-way valve (321) and a first on-off valve (322) are connected in series on the sample gas inlet pipeline (320); the first one-way valve (321) is arranged at an upstream end of the first on-off valve (322), and the conduction direction of the first one-way valve (321) is from the flow type regulator (230) to the gas sampler (310).

8. The offshore platform multiphase flow meter according to claim 4, characterized in that: The liquid discharge pipeline (340) is connected in series with a second one-way valve (342) and a second on-off valve (341); the second one-way valve (342) is arranged at a downstream end of the second on-off valve (341), and the conduction direction of the second one-way valve (342) is from the gas sampler (310) to the main pipeline.

9. The offshore platform multiphase flow meter according to claim 4, characterized in that: A second pressure transmitter (333) and at least one electric pressure reducing valve (331) are connected in series on the pressure reducing pipeline (330), and the second pressure transmitter (333) is electrically connected to the electric pressure reducing valve (331).

10. The offshore platform multiphase flow meter according to claim 5, characterized in that: A third one-way valve (351) is connected in series to the residual gas exhaust pipeline (350), and the conduction direction of the third one-way valve (351) is from the gas sampler (310) to the main pipeline.

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