CN115628788A - Transient heating type downhole pipeline fluid flow measuring device and method - Google Patents
Transient heating type downhole pipeline fluid flow measuring device and method Download PDFInfo
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- CN115628788A CN115628788A CN202211277453.XA CN202211277453A CN115628788A CN 115628788 A CN115628788 A CN 115628788A CN 202211277453 A CN202211277453 A CN 202211277453A CN 115628788 A CN115628788 A CN 115628788A
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- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
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Abstract
The invention relates to a transient heated downhole in-line fluid flow measurement apparatus and method. The heating belt is wound on the outer wall of the pipeline, and when fluid in the underground pipeline flows through the heating belt by applying an electric signal to the heating belt, the heating belt and the fluid are subjected to heat exchange, so that the temperature of the fluid is changed; the left heat insulation block and the right heat insulation block are arranged on the left side and the right side of the heating belt; the plurality of temperature sensors are arranged at different positions of the pipeline so as to measure the temperature change of the fluid flowing through, and the measurement of the fluid flow is realized by analyzing the temperature change of the plurality of temperature sensors and combining the time of the temperature change. The influence of the temperature of the heat source of the heating belt on the temperature difference signal can be reduced, and the transient heating method does not need to electrify the heating belt all the time, so that the energy-saving heating device is more energy-saving than the traditional heating mode.
Description
Technical Field
The invention relates to the field of flow detection in petroleum exploitation and production logging, in particular to a device and a method for measuring flow of fluid in a transient heating type underground pipeline.
Background
The flow detection runs through the whole process of oil exploitation and production logging, and the yield of the mixed fluid in each fluid production interval can be determined through the flow, and the position of an abnormal section when the fluid production interval is abnormal is determined. The existing flow measurement technologies mainly comprise a turbine flowmeter, a vortex shedding flowmeter, a conductance correlation method, a differential pressure flowmeter, an ultrasonic flowmeter, an optical fiber flowmeter, an electromagnetic flowmeter and a thermal flowmeter. Among them, the thermal flowmeter adopts the thermal diffusion principle, calculates the flow of the medium according to the relation of the temperature difference and the medium flow velocity, and has been widely applied to the field of oil and gas well flow measurement. However, the accuracy of the conventional thermal flow rate measurement method is affected by the heat source, and it is necessary to develop a thermal flow rate measurement device and method that reduce the influence of the heat source.
In the existing flow measurement method, a turbine flowmeter is easily influenced by factors such as the viscosity and density of a measured fluid, and the tip of a turbine is easily worn when the turbine rotates at a high speed; the vortex shedding flowmeter has poor vibration resistance and temperature resistance, poor adaptability to the measured dirty medium and high requirement on a straight pipeline; the differential pressure type flowmeter has large pressure loss, narrow measurement range, lower measurement precision and higher requirements on field installation conditions; in the ultrasonic flowmeter method, the Doppler method has low measurement precision and can only be used for measuring liquid containing a certain amount of suspended particles and bubbles, and the propagation time method can only be used for cleaning the liquid and gas; in the measuring process of the optical fiber flowmeter, along with the increase of the flow velocity, the vibration is increased, the error between an experimental value and a theoretical value is larger, and the optical fiber flowmeter is insensitive to low-speed fluid; electromagnetic flowmeters are not capable of measuring liquids with very low conductivity, gases, vapors and liquids containing large bubbles, nor are they capable of being used for fluid measurements at higher temperatures; the heating source and the temperature measuring element of the traditional contact type thermal flowmeter are directly contacted with the measured fluid, the instrument can be impacted and corroded by the fluid, and the measurement precision is low. Compared with a contact thermal flowmeter, the non-contact flowmeter is not influenced by underground pressure loss and is more suitable for underground flow measurement. However, the phase position of the heating belt and the sensor has a certain influence on the measurement accuracy. If the distance between the temperature sensor and the heating belt is too close, the measured temperature is the temperature of the heating belt; if the distance between the temperature sensor and the heating belt is too far, the thickness of the heating bracket needs to be increased, and the pressure caused by the fluid also affects the heating bracket, so that the accuracy of the heating bracket is reduced.
Disclosure of Invention
In view of the above problems, an object of the present invention is to provide a method for measuring fluid flow in a transient heating type downhole pipeline, so as to improve downhole flow measurement accuracy, solve the problem that the conventional heating method is greatly affected by a heating source, and save more energy. The pulse excitation is applied to the heating belt, the temperature change of multiple points of the pipeline is measured by using the temperature sensor after the excitation is cut off, and the flow of the fluid in the pipeline is calculated according to the average time of the temperature change in multiple pulse periods.
In order to achieve the purpose, the invention adopts the following technical scheme:
a transient heated downhole in-line fluid flow measurement apparatus comprising:
the heating belt is wound on the outer wall of the pipeline, and when fluid in the underground pipeline flows through the heating belt by applying an electric signal to the heating belt, the heating belt and the fluid are subjected to heat exchange, so that the temperature of the fluid is changed;
the left heat insulation block and the right heat insulation block are arranged on the left side and the right side of the heating belt; and
the temperature sensors are arranged at different positions of the pipeline so as to measure the temperature change of the position where the fluid flows through, and the measurement of the fluid flow is realized by analyzing the temperature change of the temperature sensors and combining the time of the temperature change.
The heating belt is made of graphene and/or silicon rubber materials.
Further comprising: and the ground module applies transient excitation signals to the heating belt through a cable and also filters, amplifies and processes the signals of the data transmitted by the temperature sensor.
The ground module comprises a Wheatstone bridge, the Wheatstone bridge comprises a compensation resistor which is the same as a temperature measuring resistor in the temperature sensor, when the ambient temperature changes, the resistance value of the compensation resistor changes along with the change of the ambient temperature, and the Wheatstone bridge is enabled to restore the balance by generating internal current through the operational amplifier feedback.
A method for measuring the flow rate of fluid in the pipeline under transient heating mode features that a transient pulse signal is applied to the heating band, the power supply is turned off after the heat pulse is continuously operated for a certain time in a signal period, and the temp responses at different positions in pipeline are measured by multiple temp sensors.
And applying heat pulse excitation to the heating belt to enable the temperature of the annular heating belt wound outside the oil pipe to be higher than the ambient temperature of the position, turning off the heating source after a period of time, measuring the temperatures of multiple points by using temperature sensors at different positions, and calculating the flow rate of the underground fluid according to the relation between the measured temperature field and the flow rate of the fluid.
Due to the adoption of the technical scheme, the invention has the following advantages:
the switch-off after the pulse excitation is applied can ensure that the temperature change measured by the temperature sensor is only related to the flow speed and the flow of the fluid and is not influenced by a heat source of the heating belt;
because the transient heating method does not need to be electrified all the time, the energy-saving heating device is more energy-saving than the traditional heating mode;
applying pulse excitation to the heating belt by using a transient heating method, measuring the temperature change of multiple points of the pipeline by using a temperature sensor after excitation is turned off, and calculating the flow of fluid in the pipeline according to the average time of the temperature change in multiple pulse periods;
the influence of the temperature of the heat source of the heating belt on the temperature difference signal can be reduced, and the transient heating method does not need to electrify the heating belt all the time, so that the energy-saving heating device is more energy-saving than the traditional heating mode.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Like reference numerals refer to like parts throughout the drawings. In the drawings:
FIG. 1 is a schematic diagram of a downhole fluid flow measurement device based on transient heating;
FIG. 2 is a schematic diagram of the operating principle of a downhole fluid flow measurement device based on transient heating;
FIG. 3 is a schematic diagram of a transient heating excitation signal; and
FIG. 4 is a schematic diagram of a Wheatstone bridge feedback circuit.
The reference symbols in the drawings denote the following:
1. a pipeline; 2. an outer protective shell; 3. a left insulating block; 4. a first temperature sensor; 5. heating the stent; 6. heating the tape; 7. a second temperature sensor; 8. a right insulating block; 9. a ground module; 10. a cable; 11. a transient heating module; 12. a temperature measurement module; 13. a circuit cabin body; 15. a Wheatstone bridge; 16. a temperature compensator; 17. a signal conditioner; 18. an A/D converter; 19. a microprocessor; 20. and outputting the flow unit.
Detailed Description
Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
According to some embodiments of the application, a transient heating mode is adopted, firstly, a heating pulse excitation is applied to a heating belt, so that the temperature of an annular heating belt wound outside an oil pipe is higher than the ambient temperature of the position, after a period of time, the heating source is turned off, and at the moment, the heat energy of the heating belt is transferred to fluid; then, measuring the temperature of the multiple points by using temperature sensors at different positions; and finally, calculating the flow rate of the underground fluid according to the relation between the measured temperature field and the flow rate of the fluid.
Fig. 1 shows a schematic diagram of a downhole fluid flow measurement device based on transient heating.
The downhole fluid flow measuring device shown in fig. 1 mainly comprises an outer casing, a left heat insulation block, a heating belt, a right heat insulation block and a temperature sensor;
the heating support can fix the heating belt at a position away from the pipe wall, so that the working stability of the heating belt is ensured;
the heating belt can be made of graphene, silicon rubber and other materials, and by applying an electric signal to the heating belt, when fluid flows through the heating belt, the heating belt exchanges heat with the fluid, so that the temperature of the fluid is changed;
the left side and the right side of the heating module are respectively provided with the heat insulation module, so that the heat dissipation of the heating quantity along the wall of the metal pipe can be reduced, the heating quantity is transferred to the inside of the fluid to the maximum extent, and the energy utilization rate is improved;
the number of the temperature sensors can be multiple, the temperature sensors are arranged at different positions of the pipeline to measure the temperature change of the flowing position of the fluid, the multipoint temperature can be detected, and the accurate measurement of the fluid flow can be realized by analyzing the temperature difference change of the temperature sensors and combining the time of the temperature difference change.
The working flow of the device is shown in fig. 2.
The ground module applies transient excitation signals to the heating belt through the cable, and heat generated by the heating belt acts on fluid in the pipeline to change the temperature of the fluid; on the basis, a plurality of temperature sensors are used for measuring the temperature difference, and meanwhile, a collecting and transmitting circuit is used for collecting temperature signals measured by the temperature sensors; the circuit bin module comprises all hardware circuits of the thermal type flow measuring device, and is used for storing, calculating and the like data transmitted by the temperature sensor and then transmitting the data to the ground module for signal filtering, amplification and processing.
The traditional downhole thermal flow measuring method is characterized in that direct current excitation is applied to a heating belt, and the temperature of a heat source with small volume is higher than the ambient temperature through constant heating. The distance between the temperature sensor and the heating belt has great influence on the flow measurement precision. If the distance between the heating belt and the heating belt is too close, the temperature measured by the temperature sensor is the temperature of the heating belt; if the distance between the two is long, the temperature difference change measured by the temperature sensor is weak, and the accuracy of flow inversion calculation is also severely limited.
Aiming at the problem, the invention provides a transient heating type downhole pipeline fluid flow measuring method. The power supply is turned off after the heat pulse is continuously operated for a period of time in one signal cycle by applying a transient pulse signal as shown in fig. 3 to the heating belt of fig. 1. Temperature responses at multiple locations of the conduit are measured at the intervals of the power shutdown using multiple temperature sensors.
Assuming that the number of excitation periods transmitted is M (M is a positive integer), the transient excitation in FIG. 3 can be expressed as
In the formula (I), the compound is shown in the specification,
i is an excitation current applied to the heating belt;
m is the number of excitation cycles;
t and t' are time instants.
As can be understood from fig. 3, the pulse heating is stopped at time (Mt '+ t), and is again performed until time (M + 1) t'.
When the heating is stopped, the high-temperature heating zone transfers heat to the low-temperature fluid, the temperature of the heating zone is lowered, the temperature of the fluid is raised, and the relationship between the temperature change of the fluid and the time is analyzed, so that thermophysical parameters such as specific heat capacity can be obtained.
The temperature and time data measured by multiple transient heating are stored, and an empirical formula is searched by a least square method, so that the measurement precision can be improved.
The voltage difference and temperature difference between any two temperature sensors (taking temperature sensor A, B as an example) in the present invention can be expressed as:
△U＝I(R B -R A ) (2)
△T＝T B -T A (3)
in the formula (I), the compound is shown in the specification,
Δ U is the voltage difference;
Δ T is the temperature difference;
i is an excitation current applied to the heating belt;
R A and R B Resistors of the first temperature sensor and the second temperature sensor respectively;
T A and T B The temperatures measured by the first temperature sensor and the second temperature sensor, respectively.
The relationship between the above-mentioned voltage difference and temperature difference can be expressed as
△U＝ζ·△T (4)
In the formula (I), the compound is shown in the specification,
ξ is the temperature coefficient of the temperature sensor.
And according to the voltage difference measured by the temperature sensor, gain amplification is carried out on the voltage difference signal, and the measurement range of the A/D converter is adjusted to obtain the optimal signal-to-noise ratio.
The temperature change caused by the change of the fluid flow can be obtained by combining the temperature coefficient of the temperature sensor.
In order to improve the measurement precision and reduce the error of the external environment temperature to the measurement result, the Wheatstone bridge is adopted as the driving circuit. The bridge is provided with a compensation resistor which is the same as the temperature measuring resistor, and the external environment temperature is the same. When the ambient temperature changes, the resistance value of the compensation resistor changes, and the Wheatstone bridge generates an internal current through the operational amplifier feedback to restore the balance of the bridge.
The flow chart is shown in fig. 4.
In some embodiments according to the present application, a transient heating type fluid flow measuring device is provided, in order to reduce the influence of temperature change on a temperature measurement result in a heating process of a heating zone, a conventional direct current heating mode is changed into transient pulse excitation heating, pulse excitation is firstly applied and then the heating zone is turned off, so that the temperature of the heating zone is diffused to fluid diffusion, the heat energy diffused to the fluid is subjected to multipoint temperature measurement, and the fluid flow can be calculated by combining temperature field diffusion time measured by a plurality of temperature sensors, so that the flow interpretation precision is improved.
Generally, the greater the heating power, the faster the flow rate of the fluid.
In this mode of operation, the time Δ T at which the micro temperature difference Δ T is caused by the Mth heat pulse reaching the downstream temperature sensor is detected M The flow Q of the fluid in the pipe can be obtained as follows:
in the formula (I), the compound is shown in the specification,
q is the fluid flow in the pipe;
l is the distance of the pipeline between the temperature sensors;
s is the cross-sectional area of the pipeline to be measured;
Δ T is the temperature difference;
Δt M is the time difference.
Compared with the traditional heating mode, the transient heating method adopted by the patent has multiple advantages, the temperature change measured by the temperature sensor can be only related to the flow speed and the flow rate of fluid by applying pulse excitation and then switching off, and the transient heating method is not influenced by a heat source of a heating belt. Because the transient heating method does not need to be electrified all the time, the energy-saving heating device is more energy-saving than the traditional heating mode.
The invention has the innovation points that a transient heating method is used for applying pulse excitation to a heating belt, the temperature change of multiple points of the pipeline is measured by using a temperature sensor after the excitation is cut off, and the flow of the fluid in the pipeline is calculated according to the average time of the temperature change in multiple pulse periods. The method can reduce the influence of the temperature of the heat source of the heating belt on the temperature difference signal, and the transient heating method does not need to electrify the heating belt all the time, so that the method is more energy-saving than the traditional heating mode.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A transient heated downhole in-line fluid flow measurement apparatus comprising:
the heating belt is wound on the outer wall of the pipeline, generates heat pulse by applying an electric signal to the heating belt, and exchanges heat with fluid when the fluid in the underground pipeline flows through the heating belt so as to change the temperature of the fluid;
the left heat insulation block and the right heat insulation block are arranged on the left side and the right side of the heating belt; and
the temperature sensors are arranged at different positions of the pipeline to measure the temperature change of the fluid flowing through, and the measurement of the fluid flow is realized by analyzing the temperature change of the temperature sensors and combining the time of the temperature change.
2. The transient heated downhole in-line fluid flow measurement device of claim 1, wherein: the heating belt is made of graphene and/or silicon rubber materials.
3. The transient heated downhole in-line fluid flow measurement device of claim 1, wherein: further comprising: and the ground module applies transient excitation current to the heating belt through a cable and also filters, amplifies and processes signals of data transmitted by the temperature sensor.
4. The transient heated downhole in-line fluid flow measurement device of claim 3, wherein: the ground module comprises a Wheatstone bridge, the Wheatstone bridge comprises a compensation resistor which is the same as a temperature measuring resistor in the temperature sensor, when the ambient temperature changes, the resistance value of the compensation resistor changes along with the change of the ambient temperature, and the Wheatstone bridge is enabled to restore the balance by generating internal current through operational amplifier feedback.
5. A method of transient heated downhole in-pipe fluid flow measurement using the transient heated downhole in-pipe fluid flow measurement apparatus of claims 1-4, characterized by: the method comprises the steps of applying transient excitation current to a heating belt to generate a heat pulse, enabling the heat pulse to work continuously for a period of time in a signal period, then switching off a heating source, and measuring temperature response of a plurality of positions of a pipeline by using a plurality of temperature sensors in a gap where the heating source is switched off.
6. The transient heated downhole in-pipe fluid flow measurement method of claim 5, wherein:
and applying heat pulse excitation to the heating belt to enable the temperature of the heating belt wound outside the pipeline to be higher than the ambient temperature of the position, turning off the heating source after a period of time, measuring the temperature of multiple points by using temperature sensors at different positions, and calculating the flow of the underground fluid according to the relationship between the measured temperature field and the flow of the fluid.
7. The transient heated downhole tubular fluid flow measurement method of claim 6, wherein:
the emission excitation period number is M, and the transient excitation is expressed as:
in the formula (I), the compound is shown in the specification,
i is the transient excitation current applied to the heating belt;
m is the number of excitation cycles;
t and
time of day;
the pulse heating is stopped at time (Mt '+ t), and pulse heating is again performed until time (M + 1) t'.
8. The method of transient heating downhole in-line fluid flow measurement of claim 7, wherein:
and in the time of stopping heating, the high-temperature heating zone transfers heat to the low-temperature fluid, the temperature of the heating zone is reduced, the temperature of the fluid is increased, the relation between the temperature change of the fluid and the time is analyzed to obtain thermophysical parameters, temperature and time data measured by multiple transient heating are stored, an empirical formula is searched by a least square method, and a measurement result is calculated.
9. The method of transient heating downhole in-line fluid flow measurement of claim 8, wherein:
the plurality of temperature sensors includes a first temperature sensor and a second temperature sensor, and a voltage difference and a temperature difference between the first temperature sensor and the second temperature sensor are respectively expressed as:
△U＝I(R B -R A ) (2)
△T＝T B -T A (3)
in the formula (I), the compound is shown in the specification,
Δ U is the voltage difference;
Δ T is the temperature difference;
i is the transient excitation current applied to the heating belt;
R A and R B Resistors of the first temperature sensor and the second temperature sensor respectively;
T A and T B The temperatures measured by the first temperature sensor and the second temperature sensor respectively;
the relationship between the voltage difference and the temperature difference is expressed as Δ U = ζ · Δ T (4)
In the formula (I), the compound is shown in the specification,
ξ is the temperature coefficient of the temperature sensor,
the temperature change caused by the change of the fluid flow can be obtained by combining the temperature coefficient of the temperature sensor.
10. The method of transient heating downhole in-line fluid flow measurement of claim 9, wherein:
by detecting the time when the Mth heat pulse reaches the downstream temperature sensor to cause micro temperature difference, the flow rate of the fluid in the pipe is obtained as follows:
in the formula (I), the compound is shown in the specification,
q is the fluid flow in the pipe;
l is the distance of the pipeline between the temperature sensors;
Δt M is the time difference;
and S is the cross-sectional area of the pipeline to be measured.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202211277453.XA CN115628788A (en) | 2022-10-19 | 2022-10-19 | Transient heating type downhole pipeline fluid flow measuring device and method |
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| CN202211277453.XA CN115628788A (en) | 2022-10-19 | 2022-10-19 | Transient heating type downhole pipeline fluid flow measuring device and method |
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| CN115628788A true CN115628788A (en) | 2023-01-20 |
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| CN202211277453.XA Pending CN115628788A (en) | 2022-10-19 | 2022-10-19 | Transient heating type downhole pipeline fluid flow measuring device and method |
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