A high temperature resistant oil-water two-phase flow measurement method and device based on thermal tracing

Abstract

The present invention provides a method and device for measuring a high-temperature resistant oil-water two-phase flow based on thermal tracing. The high-temperature resistant thermal tracer velocity measuring instrument uses an upstream temperature probe to measure multiple times to obtain the maximum temperature difference in the well, and determines the heat source pulse heating power that meets the measurement requirements of oil wells with various water contents in the tertiary oil recovery stage. The temperature of the circuit of the high-temperature resistant thermal tracer velocity measuring instrument is obtained by using the microelement thermal balance method, and the spatial thermal layout of the circuit is optimized by using a genetic algorithm with the goal of reducing the maximum temperature, the average temperature and improving the temperature uniformity of the circuit. A corresponding heat dissipation housing is designed for the optimized circuit layout of the high-temperature resistant thermal tracer velocity measuring instrument to further reduce the circuit temperature of the high-temperature resistant thermal tracer velocity measuring instrument. After the circuit remains stable, the flow parameters in the pipe are obtained by using a temperature mutation signal processing circuit. The present invention overcomes the phenomenon that the traditional turbine flowmeter based on movable parts is easily affected by fluid viscosity and carried gravel, resulting in sand jamming and failure, and can be applied to high-temperature oil wells.

Description

Technical field:

[0001] The invention belongs to the field of petroleum engineering and measurement technology, and in particular relates to a high-temperature resistant oil-water two-phase flow measurement method and device based on thermal tracing. Background technology:

[0002] When oil fields enter the middle and late stages of exploitation, hydraulic fracturing, chemical flooding, and small-diameter horizontal wells are often used to increase oil field recovery rates, which leads to increased fluid viscosity and the carrying of sand and gravel. Traditional turbine flowmeters are blocked by sand and fail to measure. The thermal tracer flowmeter designed with non-movable components is not affected by factors such as fluid carrying sand and gravel, and can measure oil-water two-phase flow in small-diameter horizontal wells. At the same time, with the continuous development of exploration technology, the average temperature in the well is also increasing. In high-temperature conditions underground, the heat generated by electronic components cannot be well diffused and accumulates, which will cause the temperature of the device to rise sharply, affecting normal operation and even burning the device.

[0003] To address the above problems, a high-temperature two-phase flow velocity measurement method based on the heat tracer principle was proposed. The spatial thermal layout optimization and heat dissipation shell design of the high-temperature resistant heat tracer circuit were carried out to control the temperature of the components within their own operating temperature range when reaching thermal equilibrium. Summary of the invention:

[0004] The purpose of the present invention is to overcome the sand sticking failure phenomenon of traditional turbine flowmeters based on movable parts in the middle and late stages of oil field exploitation, while meeting the measurement needs of high-temperature oil wells entering the tertiary oil recovery stage, and to provide a high-temperature resistant oil-water two-phase flow measurement method and device based on thermal tracing.

[0005] The technical solution adopted by the present invention is: a high temperature resistant oil-water two-phase flow measurement method and device based on thermal tracing, characterized in that: the measurement device comprises: an upstream temperature probe (1), a heat source (2), a downstream first-stage thermal sensor (3), a downstream second-stage thermal sensor (4), a counterweight (5) and an electronic short section (6). The electronic short section mainly comprises a boss-fin heat dissipation shell and a high temperature resistant thermal tracer flow velocity measuring instrument circuit board. The boss-fin heat dissipation shell is composed of an aluminum square tube (7), heat dissipation ribs (8) and a stretching boss (9). The high temperature resistant thermal tracer flow velocity measuring instrument circuit board (12) is fixedly adhered to the lower inner wall of the heat dissipation shell by fixing bolts (10) and thermal conductive silicone grease (11), and the heat dissipation shell is connected to the temperature-exceeding component (13) through the stretching boss (9). The two counterweights (5) and the electronic short section (6) support the high temperature resistant thermal tracer flow velocity measuring instrument without being affected by fluid impact, thereby ensuring measurement accuracy.

[0006] The technical solution adopted by the present invention is: a high temperature resistant oil-water two-phase flow measurement method and device based on thermal tracing, the high temperature resistant oil-water two-phase flow measurement method based on thermal tracing comprises the following steps:

[0007] Step 1: Use the upstream temperature probe (1) to measure multiple times to determine the maximum temperature difference in the well, and calculate the heating power of the thermal tracer flow meter that is suitable for various water content conditions;

[0008] Furthermore, the method for calculating the heating power of the high temperature resistant heat tracer flow meter adapted to various water content conditions is as follows:

[0009] The maximum temperature fluctuation in the well is determined to be Vt by multiple measurements using the upstream temperature probe (1). max , the surface temperature t after the heat source (2) is heated for a short time ΔT j1 for:

[0010]

[0011] Where P is the heating power of the heat source, ΔT is the pulse heating time, c h is the specific heat capacity of the heat source material, ρ h is the heat source material density, V is the heat source volume, t f0 is the heat source and the initial temperature of the fluid in the well.

[0012] The heat transfer Q of the fluid after passing through the heated heat source is forced convection f for:

[0013] Q f =h f s(t j1 -t f0 )

[0014] Among them, h f is the fluid convection heat transfer coefficient, and s is the surface area of ​​the heat source.

[0015] The temperature of the heated fluid is t f1 for:

[0016]

[0017] Among them, c f is the specific heat capacity of the fluid, ρ f is the fluid density, r is the pipe radius, v f is the fluid flow rate. The specific heat capacity, thermal conductivity and thermal diffusion coefficient of oil are much smaller than those of water. Therefore, when the flow rate in the pipe is constant, water takes away more heat from the heater. In order to meet the measurement requirements of various working conditions, the temperature change of the heated fluid must be at least greater than the maximum temperature fluctuation in the pure oil well, that is:

[0018]

[0019] Among them, c o is the specific heat capacity of oil, ρ o is the oil density, h o is the convective heat transfer coefficient of the oil. Therefore, the pulse heating power P must meet the following conditions:

[0020]

[0021] Step 2: Divide the circuit board of the high temperature resistant flow velocity measuring instrument based on heat tracing into a grid board with m rows and n columns, and use the microelement heat balance method to obtain the temperature of the electronic components;

[0022] Furthermore, the method of obtaining the temperature of the electronic components by using the microelement thermal balance method in the above step 2 is as follows:

[0023] The circuit board is divided into m×n small grids of equal area. The (m-1)×(n-1) nodes correspond to the electronic components of different powers in the measuring instrument. The components are assumed to be l long. a , width is l b , height is l c The sum of the heat generated by the electronic components at the middle node (i, j), the heat transferred by the PCB board, and the convection exchange heat in the space is zero, so the node temperature function can be obtained as:

[0024]

[0025] Among them, α e-c is the convective heat transfer coefficient between the node and the surrounding air; t e-∞ is the temperature of the air around the node; T i,j is the temperature of the node; l d is the thickness of the circuit board; p is the thermal conductivity of the circuit board; α p-e is the heat transfer coefficient between the circuit board and the electronic components; α p-a is the convection heat transfer coefficient between the circuit board and the air; c is the thermal conductivity of electronic components; g is the thermal conductivity of the air inside the instrument; l e is the left and right spacing of electronic components; l f It is the front and back distance of electronic components.

[0026] Step 3: Establish a fitness function with the goal of reducing the maximum temperature and average temperature of the circuit board and improving the temperature uniformity of the circuit. Use the internal genetic algorithm to optimize the weight coefficients of the three fitness functions, and the external genetic algorithm to optimize the circuit layout.

[0027] Furthermore, in the above step 3, the electronic components are divided into grids according to the step 2, and the method of optimizing the layout of the components using the genetic algorithm is as follows: S1:P N ∈{p1,p1,L,p n} represents different arrangements and layouts of electronic components, W n ∈{w1,w2,w3} represents the weighted combination of three fitness functions. The initial population is randomly generated. For each P N Chromosomes, the internal genetic algorithm randomly generates weights W n of the overall.

[0028] S2: According to the temperature function of each electronic component obtained in step 2, establish a fitness function:

[0029]

[0030] Among them, the circuit maximum temperature function f(T high ):

[0031]

[0032] T k is the node component temperature; T max is the maximum operating temperature of the component.

[0033] Temperature mean square error function f(T δ ):

[0034]

[0035] Mean temperature function

[0036]

[0037] S3: The internal genetic algorithm optimizes the weighted combination of the objective function, and the external genetic algorithm optimizes the fitness function of the circuit board layout. w , G N are the iteration numbers of the internal and external genetic algorithms respectively, and the fitness function is used Execute the optimization process based on genetic algorithm. At this time, f(T high )、f(T δ ), is fixed, and its weight combination is optimized. Repeat the internal genetic algorithm, iterate G w times, and then repeat for other chromosomes P. In the external genetic algorithm, each chromosome P obtains the associated optimal weight combination w1, w2, w3 from the internal genetic algorithm for fitness evaluation.

[0038] S4: Termination condition determination: fitness function obtained by comparing different layouts If the size is smaller than the original layout, the position is updated until the population evolution reaches G N The algorithm terminates and the optimized position is obtained.

[0039] Step 4: Design the corresponding heat dissipation shell according to the layout optimized in step 3, connect the heat dissipation bosses with the components with excessive temperature, and determine the optimized heat dissipation amount of the boss-fin shell.

[0040] Furthermore, in the above step 4, a corresponding heat dissipation housing is designed according to the layout optimized in step 3, the heat dissipation boss is connected to the temperature-exceeding components, and the method for determining the heat dissipation optimization amount of the boss-fin housing is as follows:

[0041] After optimizing the layout, it is determined that the temperature of an electronic component that exceeds the standard is t c , length and width are both l x , the heat exchange between the upper surface of the electronic component and the air inside the instrument is Q c-h for:

[0042] Q c-h =α e-c l x 2 (t c -t e-∞ )

[0043] Place the heat dissipation boss in contact with the component with excessive temperature, and apply thermal grease between the two to fill the gap. Set the fin heat dissipation rate η s , simplify the boss and fin directly connected to the over-standard electronic component to the base thickness l δ , finned heat sink with n fins.

[0044] The heat dissipation of a single fin is:

[0045] Q one =η s h f (t c -t f0 )[2(l h ·l w +l h ·l x )+l x ·l w ]

[0046] Among them, l w , l h are the width and height of a single fin respectively; the convection heat transfer area of ​​the boss base can be calculated as: S d =4l δ l x +(l x-nl w ) x , then the heat transfer of the substrate can be expressed as:

[0047] Q d =h f ·(t c -t f0 )·[4l δ l x +(l x -nl w ) x ]

[0048] The forced convection heat transfer of the entire finned radiator can be expressed as:

[0049] Q s =Q d +n·Q one =h f ·(t c -t f0 )·{4l δ l x +(l x -nl w ) x +nη s [2(l h ·l w +l h ·l x )+l x ·l w ]}

[0050] The components with excessive temperature can use the boss-fin heat dissipation shell to improve the heat dissipation by Q compared with the heat dissipation by the air inside the instrument. g :

[0051] Q g =h f ·(t c -t f0 )·{4l δ l x +(l x -nl w ) x +nη s [2(l h ·l w +l h ·l x )+l x ·l w ]}-α e-c l x 2 (t c -t e-∞ )

[0052] Step 5: After the electronic components remain stable, the temperature mutation signal processing circuit is used to obtain the transit time τ of the heat flow group flowing through the downstream adjacent thermal sensors. The distance between the two adjacent thermal sensors is known to be l l .

[0053] Pipeline flow rate Q f for:

[0054] Q f =πr 2 v f =πr 2 l l / τ.

[0055] The beneficial effects of the present invention are as follows: the problem of sand jamming and blockage in measuring the flow rate parameters of old oil wells with extremely high water content caused by traditional flow meters based on movable parts is overcome, and a high-temperature resistant oil-water two-phase flow measurement method and device based on thermal tracing is provided for the measurement needs of high-temperature oil wells entering the tertiary oil recovery stage. The main advantages are as follows:

[0056] (1) The flow meter designed based on the heat tracer principle proposed in the present invention has all its components fixed on the surface of the instrument housing, so that the heat tracer flow meter is not affected by factors such as fluid viscosity and carried gravel during flow measurement.

[0057] (2) The maximum temperature difference in the well is measured multiple times using the upstream temperature probe, and the minimum heating power of the high-temperature resistant heat tracer flow meter is determined. This expands the application scenarios of the high-temperature resistant heat tracer flow meter and meets the flow rate measurement needs of oil wells with different water contents in the tertiary oil recovery stage.

[0058] (3) The circuit temperature of the high-temperature resistant thermal tracer flow meter is obtained by using the microelement thermal balance method. The fitness function is established with the goal of reducing the maximum temperature and average temperature of the circuit board and improving the temperature uniformity of the circuit board. The weight coefficients of the three fitness functions are optimized using an internal genetic algorithm, and the circuit thermal layout is optimized using an external genetic algorithm.

[0059] (4) Design the corresponding heat dissipation shell according to the optimized layout, connect the heat dissipation boss to the components with excessive temperature, and determine the optimized heat dissipation amount of the boss-fin shell.

[0060] (5) The above thermal design ensures the stability of the high temperature resistant heat tracer circuit, and the temperature mutation signal processing circuit is used to obtain the transit time of the heat flow group flowing through the downstream adjacent thermistor, and then the flow information of the fluid in the pipe is obtained. Description of the drawings:

[0061] Figure 1 It is a schematic diagram of the structure of a high temperature resistant heat tracer flow velocity measuring instrument;

[0062] Figure 2 This is a schematic diagram of the electronic short section structure of a high temperature resistant heat tracer flow meter;

[0063] Figure 3 It is a schematic diagram of the heat transfer model of the electronic short section of the high temperature resistant heat tracer flow velocity measuring instrument in the well;

[0064] Figure 4 It is a schematic diagram of the heat transfer process of the circuit of the high temperature resistant heat tracer flow velocity measuring instrument;

[0065] Figure 5 This is a schematic diagram of circuit board mesh division based on microelement thermal balance method;

[0066] Figure 6 Optimize the circuit flow chart of high temperature resistant heat tracer flow meter for genetic algorithm;

[0067] Figure 7 This is the original layout temperature diagram of the high temperature resistant heat tracer flow velocity measuring instrument circuit;

[0068] Figure 8 Temperature diagram after optimizing the thermal layout of the circuit for high temperature resistant thermal tracer flow velocity measuring instrument;

[0069] Fig. 9 A schematic diagram of high temperature testing of the circuit of a high temperature resistant heat tracer flow velocity measuring instrument;

[0070] Fig.10 This is a diagram of the measurement results of the high temperature resistant thermal tracer flow velocity measuring instrument in different temperature environments; Specific implementation method:

[0071] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0072] Embodiment 1

[0073] Reference Figure 1 This paper designs a high temperature resistant oil-water two-phase flow measurement device based on thermal tracing, which is characterized in that the measurement device includes: an upstream temperature probe (1), a heat source (2), a downstream first-stage thermal sensor (3), a downstream second-stage thermal sensor (4), a weight plate (5) and an electronic short section (6). Figure 2The electronic short section mainly includes a boss-fin heat dissipation shell and a high-temperature resistant heat tracer flow meter circuit board. The boss-fin heat dissipation shell is composed of an aluminum square tube (7), heat dissipation ribs (8) and a stretched boss (9). The high-temperature resistant heat tracer flow meter circuit board (12) is fixedly adhered to the lower inner wall of the heat dissipation shell by fixing bolts (10) and thermal grease (11), and the heat dissipation shell is connected to the temperature-exceeding component (13) through the stretched boss (9). Two counterweights (5) and the electronic short section (6) support the high-temperature resistant heat tracer flow meter and are not affected by the impact of the fluid in the pipe, thereby ensuring the measurement accuracy.

[0074] Embodiment 2

[0075] A high temperature resistant oil-water two-phase flow measurement method and device based on thermal tracing, the measurement method comprising the following steps:

[0076] Step 1: Use the upstream temperature probe to measure multiple times to determine the maximum temperature difference in the well, and calculate the heating power of the thermal tracer flow meter that is suitable for various water content conditions;

[0077] Furthermore, the method for calculating the heating power of the high temperature resistant heat tracer flow meter adapted to various water content conditions is as follows:

[0078] The maximum temperature fluctuation in the well is determined to be Vt by multiple measurements using the upstream temperature probe (1). max , the surface temperature t after the heat source (2) is heated for a short time ΔT j1 for:

[0079]

[0080] Where P is the heating power of the heat source, ΔT is the pulse heating time, c h is the specific heat capacity of the heat source material, ρ h is the heat source material density, V is the heat source volume, t f0 is the heat source and the initial temperature of the fluid in the well.

[0081] The heat transfer Q of the fluid after passing through the heated heat source is forced convection f for:

[0082] Q f =h f s(t j1 -t f0 )

[0083] Among them, h f is the fluid convection heat transfer coefficient, and s is the surface area of ​​the heat source.

[0084] The temperature of the heated fluid is t f1 for:

[0085]

[0086] Among them, c f is the specific heat capacity of the fluid, ρ f is the fluid density, r is the pipe radius, v f is the fluid flow rate. The specific heat capacity, thermal conductivity and thermal diffusion coefficient of oil are much smaller than those of water. Therefore, when the flow rate in the pipe is constant, water takes away more heat from the heater. In order to meet the measurement requirements of various working conditions, the temperature change of the heated fluid must be at least greater than the maximum temperature fluctuation in the pure oil well, that is:

[0087]

[0088] Among them, c o is the specific heat capacity of oil, ρ o is the oil density, h o is the convective heat transfer coefficient of the oil. Therefore, the pulse heating power P must meet the following conditions:

[0089]

[0090] Step 2: Divide the circuit board of the high temperature resistant flow velocity measuring instrument based on heat tracing into a grid board with m rows and n columns, and use the microelement heat balance method to obtain the temperature of the electronic components;

[0091] Furthermore, the method of obtaining the temperature of the electronic components by using the microelement thermal balance method in the above step 2 is as follows:

[0092] Reference Figure 3-Figure 4 The heat transfer process of the high temperature resistant heat tracer flow rate measuring instrument in the actual working conditions underground divides the circuit board into Figure 5 The m×n small grids with equal areas are shown in the figure. The (m-1)×(n-1) nodes correspond to the electronic components with different powers in the measuring instrument. The components are assumed to be l long. a , width is l b , height is l c The sum of the heat generated by the electronic components at the middle node (i, j), the heat transferred by the PCB board, and the convection exchange heat in the space is zero, so the node temperature function can be obtained as:

[0093]

[0094] Among them, α e-c is the convective heat transfer coefficient between the node and the surrounding air; t e-∞ is the temperature of the air around the node; T i,j is the temperature of the node; l d is the thickness of the circuit board; p is the thermal conductivity of the circuit board; α p-e is the heat transfer coefficient between the circuit board and the electronic components; αp-a is the convection heat transfer coefficient between the circuit board and the air; c is the thermal conductivity of electronic components; g is the thermal conductivity of the air inside the instrument; l e is the left and right spacing of electronic components; l f It is the front and back distance of electronic components.

[0095] Step 3: Establish a fitness function with the goal of reducing the maximum temperature and average temperature of the circuit board and improving the temperature uniformity of the circuit. Use the internal genetic algorithm to optimize the weight coefficients of the three fitness functions, and the external genetic algorithm to optimize the circuit layout.

[0096] Furthermore, in the above step 3, the electronic components are divided into grids according to the step 2, and the method of optimizing the component layout using the genetic algorithm is as follows:

[0097] S1:P N ∈{p1,p1,L,p n} represents different arrangements and layouts of electronic components, W n ∈{w1,w2,w3} represents the weighted combination of three fitness functions. The initial population is randomly generated. For each P N Chromosomes, the internal genetic algorithm randomly generates weights W n of the overall.

[0098] S2: According to the temperature function of each electronic component obtained in step 2, establish a fitness function:

[0099]

[0100] Among them, the circuit maximum temperature function f(T high ):

[0101]

[0102] T k is the node component temperature; T max is the maximum operating temperature of the component.

[0103] Temperature mean square error function f(T δ ):

[0104]

[0105] Mean temperature function

[0106]

[0107] S3: Reference Figure 6The internal genetic algorithm optimizes the weighted combination of the objective function, and the external genetic algorithm optimizes the fitness function of the circuit board layout. w , G N are the iteration numbers of the internal and external genetic algorithms respectively, and the fitness function is used Execute the optimization process based on genetic algorithm. At this time, f(T high )、f(T δ ), is fixed, and its weight combination is optimized. Repeat the internal genetic algorithm, iterate G w times, and then repeat for other chromosomes P. In the external genetic algorithm, each chromosome P obtains the associated optimal weight combination w1, w2, w3 from the internal genetic algorithm for fitness evaluation.

[0108] S4: Termination condition determination: fitness function obtained by comparing different layouts If the size is smaller than the original layout, the position is updated until the population evolution reaches G N The algorithm terminates and the optimized position is obtained.

[0109] Reference Figure 7-Figure 8 ,Under 150 degrees Celsius working conditions, the maximum steady-state temperature of the high-temperature resistant thermal tracer flow meter after layout optimization was improved by 10.35% compared with the original circuit layout, but some components still exceeded the maximum operating temperature.

[0110] Step 4: Design the corresponding heat dissipation shell according to the layout optimized in step 3, connect the heat dissipation bosses with the components with excessive temperature, and determine the optimized heat dissipation amount of the boss-fin shell.

[0111] Furthermore, in the above step 4, a corresponding heat dissipation housing is designed according to the layout optimized in step 3, the heat dissipation boss is connected to the temperature-exceeding components, and the method for determining the heat dissipation optimization amount of the boss-fin housing is as follows:

[0112] Reference Figure 7-Figure 8 , comparing the circuit temperature of the high temperature resistant heat tracer flow velocity measuring instrument before and after the optimized layout, it is determined that the temperature of a certain electronic component exceeding the standard after the optimized layout is t c , length and width are both l x , the heat exchange between the upper surface of the electronic component and the air inside the instrument is Q c-h for:

[0113] Q c-h =α e-c l x 2 (t c -t e-∞ )

[0114] Place the heat dissipation boss in contact with the component with excessive temperature, and apply thermal grease between the two to fill the gap. Set the fin heat dissipation rate η s , simplify the boss and fin directly connected to the over-standard electronic component to the base thickness l δ , finned heat sink with n fins.

[0115] The heat dissipation of a single fin is:

[0116] Q one =η s h f (t c -t f0 )[2(l h ·l w +l h ·l x )+l x ·l w ]

[0117] Among them, l w , l h are the width and height of a single fin respectively; the convection heat transfer area of ​​the boss base can be calculated as: S d =4l δ l x +(l x -nl w ) x , then the heat transfer of the substrate can be expressed as:

[0118] Q d =h f ·(t c -t f0 )·[4l δ l x +(l x -nl w ) x ]

[0119] The forced convection heat transfer of the entire finned radiator can be expressed as:

[0120] Q s =Q d +n·Q one =h f ·(t c -t f0 )·{4l δ l x +(l x -nl w ) x +nη s [2(l h ·l w +l h·l x )+l x ·l w ]}

[0121] The components with excessive temperature can use the boss-fin heat dissipation shell to improve the heat dissipation by Q compared with the heat dissipation by the air inside the instrument. g :

[0122] Q g =h f ·(t c -t f0 )·{4l δ l x +(l x -nl w ) x +nη s [2(l h ·l w +l h ·l x )+l x ·l w ]}-α e-c l x 2 (t c -t e-∞ )

[0123] Step 5: After the electronic components remain stable, the temperature mutation signal processing circuit is used to obtain the transit time τ of the heat flow group flowing through the downstream adjacent thermal sensors. The distance between the two adjacent thermal sensors is known to be l l .

[0124] Pipeline flow rate Q f for:

[0125] Q f =πr 2 v f =πr 2 l l / τ.

[0126] Build as Fig. 9The high temperature test platform shown in the figure verifies the reliability of the high temperature resistant thermal tracer flow meter in a high temperature environment. Use a constant temperature heater to heat the thermal oil to the specified temperature, use a control valve to adjust the thermal oil flow rate to 0.3m / s, and wrap the pipe with thermal insulation material to prevent heat leakage. Place the aluminum square tube containing the circuit board and the finned heat sink in the pipe and fix it in the high and low temperature variable test box. The temperature sensor array is connected to the temperature mutation signal processing circuit on the PCB board, and the data output interface is connected to the PC end. The temperature box and the oil tank are heated to 80°C. After the constant temperature is maintained for 30 minutes, the water content of the oil-water two-phase flow is fixed at 95%, and the flow rate increases by 0.023m / s per step, from 0.032m / s to 0.492m / s. Keep the same conditions and repeat the measurement 10 times, and take the average value of the measured data. Heat the constant temperature box and the thermal oil tank to 150°C, and the other conditions are consistent with the steps. Measure 10 times and take the average value. Record data as follows Fig.10 As shown, the measurement accuracy of the high temperature resistant heat tracer flow meter circuit remains basically unchanged in 80℃ and 150℃ environments.

[0127] The above content is a further detailed description of the present invention in combination with specific implementation methods, and it cannot be determined that the present invention is limited to the above specific implementation. Without departing from the spirit of the present invention, several changes or modifications can be made, and all similar implementations with equivalent structures, functions or uses to the invention should be deemed to belong to the protection scope of the present invention.

Claims

1. A high temperature resistant oil-water two-phase flow measurement method based on thermal tracing, characterized in that The measuring method comprises the following steps: Step 1: Determine the heating power of the thermal tracer flow meter that is suitable for various water content conditions; The maximum temperature fluctuation in the well is determined to be Δt by multiple measurements using the upstream temperature probe (1). max , the surface temperature t after the heat source (2) is heated for a short time △T j1 for: Where P is the heating power of the heat source, △T is the pulse heating time, c h is the specific heat capacity of the heat source material, ρ h is the heat source material density, V is the heat source volume, t f0 is the heat source and the initial temperature of the fluid in the well; The heat transfer Q of the fluid after passing through the heated heat source is forced convection f for: Q f =h f s(t j1 -t f0 ) Among them, h f is the fluid convection heat transfer coefficient, s is the surface area of ​​the heat source; The temperature of the heated fluid is t f1 for: Among them, c f is the specific heat capacity of the fluid, ρ f is the fluid density, r is the pipe radius, v f is the fluid flow rate; The temperature change of the heated fluid must be at least greater than the maximum temperature fluctuation in the pure oil well, that is: Among them, c o is the specific heat capacity of oil, ρ o is the oil density, h o is the convective heat transfer coefficient of the oil; therefore, the pulse heating power P must meet the following conditions: Step 2: Use the microelement thermal balance method to calculate the temperature of electronic components; Step 3: Establish a fitness function with the goal of reducing the maximum temperature and average temperature of the circuit board and improving the temperature uniformity of the circuit. Use the internal genetic algorithm to optimize the weight coefficients of the three fitness functions, and the external genetic algorithm to optimize the circuit layout. S1: Randomly generate the initial population, for each P N Chromosomes, the internal genetic algorithm randomly generates weights W n of the totality; S2: Establishing a fitness function according to the temperature functions of each electronic component obtained in step 2; S3: using an internal genetic algorithm to optimize the weight combination of the objective function and using an external genetic algorithm to optimize the fitness function of the circuit board layout; S4: Termination condition determination: fitness function obtained by comparing different layouts If the size is smaller than the original layout, the position is updated until the population evolution reaches G N The algorithm terminates and the optimized position is obtained; Step 4: Design a corresponding heat dissipation shell according to the optimized layout in step 3, and determine the heat dissipation optimization amount of the boss-fin shell; After optimizing the layout, it is determined that the temperature of an electronic component that exceeds the standard is t c , length and width are both l x , the heat exchange between the upper surface of the electronic component and the air inside the instrument is Q c-h for: Q c-h =α e-c l x 2 (t c -t e-∞ ) Place the heat dissipation boss in contact with the component with excessive temperature, and apply thermal grease between the two to fill the gap; set the fin heat dissipation rate η s , simplify the boss and fin directly connected to the over-standard electronic component to the base thickness l δ , a finned heat sink with n fins; The heat dissipation of a single fin is: Q one =η s h f (t c -t f0 )[2(l h ·l w +l h ·l x )+l x ·l w ] Among them, l w , l h are the width and height of a single fin respectively; the convection heat transfer area of ​​the boss base can be calculated as: S d =4l δ l x +(l x -nl w ) x , then the heat transfer of the substrate can be expressed as: Q d =h f ·(t c -t f0 )·[4l δ l x +(l x -nl w )l x ] The forced convection heat transfer of the entire finned radiator can be expressed as: Q s =Q d +n·Q one =h f ·(t c -t f0 )·{4l δ l x +(l x -nl w )l x +nη s [2(l h ·l w +l h ·l x )+l x ·l w ]} The components with excessive temperature can use the boss-fin heat dissipation shell to improve the heat dissipation by Q compared with the heat dissipation by the air inside the instrument. g : Q g =h f ·(t c -t f0 )·{4l δ l x +(l x -nl w )l x +nη s [2(l h ·l w +l h ·l x )+l x ·l w ]}-α e-c l x 2 (t c -t e-∞ ) Step 5: Determine the pipeline flow rate Q using the temperature mutation signal f .

2. According to the high temperature resistant oil-water two-phase flow measurement method based on thermal tracing according to claim 1, the method for calculating the temperature of electronic components using the microelement heat balance method is as follows: The circuit board is divided into m×n small grids of equal area. The (m-1)×(n-1) nodes correspond to the electronic components of different powers in the measuring instrument. The components are assumed to be l long. a , width is l b , height is l c The sum of the heat generated by the electronic components at the middle node (i, j), the heat transferred by the PCB board and the convection exchange heat in the space is zero, so the node temperature function can be obtained as follows: in, α e-c is the convective heat transfer coefficient between the node and the surrounding air; t e-∞ is the temperature of the air around the node; T i,j is the temperature of the node; l d is the thickness of the circuit board; p is the thermal conductivity of the circuit board; α p-e is the heat transfer coefficient between the circuit board and the electronic components; α p-a is the convection heat transfer coefficient between the circuit board and the air; c is the thermal conductivity of electronic components; g is the thermal conductivity of the air inside the instrument; l e is the left and right spacing of electronic components; l f It is the front and back distance of electronic components.

3. According to the high temperature resistant oil-water two-phase flow measurement method based on thermal tracing in claim 2, the weight coefficients of the three fitness functions are optimized by using an internal genetic algorithm and the circuit layout is optimized by using an external genetic algorithm as follows: S1 in P N ∈{p1,p1,…,p n } represents different arrangements and layouts of electronic components, n ∈{w1,w2,w3} represents the weighted combination of three fitness functions; The method of establishing the fitness function in S2 is as follows: in, Circuit maximum temperature function f(T high ): T k is the node component temperature; T max is the maximum operating temperature of the component; Temperature mean square error function f(T δ ): Mean temperature function The method of using the internal genetic algorithm to optimize the weight combination of the objective function and the external genetic algorithm to optimize the fitness function of the circuit board layout in S3 is as follows: G w , G N are the iteration numbers of the internal and external genetic algorithms, respectively, using the fitness function Perform genetic algorithm-based optimization process; f(T) corresponding to each chromosome high )、f(T δ ), is fixed, and its weight combination is optimized; repeat the internal genetic algorithm, iterate G w times, and then repeat for other chromosomes P; in the external genetic algorithm, each chromosome P obtains the associated optimal weight combination w1, w2, w3 from the internal genetic algorithm for fitness evaluation.

4. According to the high temperature resistant oil-water two-phase flow measurement method based on thermal tracing described in claim 3, the pipeline flow rate Q is determined f Here’s how: The temperature mutation signal processing circuit is used to obtain the transit time τ of the heat flow group passing through the adjacent downstream thermal sensors. The distance between the two adjacent thermal sensors is known to be l l ; Pipeline flow Q f for: Q f =πr 2 v f =πr 2 l l / t.

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