RU2599740C1 - Method of measuring flow rate of fluid in the well and a self-contained well thermal anemometer for its implementation - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry and can be used for geophysical exploration in horizontal and inclined operating oil wells. Method of measuring flow rate of fluid in well means pulse heating of fluid flow, measurement of temperature of fluid with at least two temperature sensors, spaced apart along the well axis, and comparison of signals of two temperature sensors. Heating is initiated by means of independent borehole heat loss anemometer. Thermal anemometer has a power supply unit, sealed cylindrical housing, in upper part of which there is a sealed compartment containing a computer system. In lower part of anemometer along the body axis there is a through opening of oval section, which formes a cylindrical channel with located inside it two temperature sensors, that are in opposite walls of channel along the body axis. In the computer system when measuring temperature is recorded from the first sensor which measures initial temperature in the borehole fluid, and from the second sensor which measures temperature of heated by means of pulse-width modulation fluid in the channel of heat loss anemometer above the other temperature sensor. Fluid flow velocity in the well is found by determining the difference of measured temperatures from the first and second sensors, on the basis of which, taking into account the initial temperature of well fluid flow, is calculated by mathematical expression, considering coefficients calculated during calibration in operating temperature range.

EFFECT: high measurement accuracy.

14 cl, 2 dwg

Description

FIELD OF TECHNOLOGY

The group of inventions relates to the oil and gas industry and can be used in geophysical surveys in horizontal and directional operating oil wells.

BACKGROUND

From US 2011/0315375 A1 (publ. 12/29/2011, IPC E21B 47/00, MOSCATO TULLIO (FR), etc.), a device is known for measuring fluid velocity in a well containing a flexible pipe in which there is a system for measuring fluid velocity in well, including a heater with a temperature sensor and environmental sensors. The temperature difference between the heated temperature sensor and the ambient sensor determines the speed of fluid movement in the well.

A method for measuring fluid velocity in a well includes the following operations:

- placing the downhole system in a well with a plurality of sensing elements, wherein each of the plurality of sensing elements comprises at least one heater and at least one temperature sensor;

- measurement of the primary parameters of the fluid fluid in the well from the first part of the plurality of sensor elements operating as a heater and the second part of the plurality of sensor elements operating as a temperature sensor;

- measurement of the secondary parameters of the fluid fluid in the well from the second part of the plurality of sensor elements operating as a heater and the first part of the plurality of sensor elements operating as temperature sensors;

- calculation of fluid velocity in the well based on at least one primary and secondary measurement of fluid parameters.

The closest analogue of the proposed group of inventions is a method and apparatus for measuring the flow rate of a liquid disclosed in RU 2280159 C2 (publ. July 20, 2006, IPC Е21В 47/10, OJSC NPP VNIIGIS (RU), etc.). The device disclosed in the closest analogue includes a pulsed fluid flow heater, a generator of current pulses of a heater, one or more pairs of temperature sensors, amplifiers, a demultiplexer, an analog-to-digital converter, a microcontroller, and a transmit-receive unit. Moreover, the device further comprises a unit for automatically adjusting the period of the current pulses of the heater in accordance with the flow rate, a pair of temperature sensors installed in one direction from the heater, where the distance between the sensors is no more than 2 times different from the distance between the heater and the sensor closest to it.

The method for measuring the velocity of a fluid flow in a well, disclosed in the closest analogue, consists in pulse heating of a fluid flow, measuring the temperature of a fluid with temperature sensors spaced along the axis of the well, and comparing the signals of two temperature sensors, where the temperature is recorded during the measurement during thermal waves of liquid formed after the passage of the heater, using two temperature sensors located in the same direction from the heater, and the fluid flow rate found by correlating the signals of the first and second sensors, determining the delay time of thermal waves at a distance from the nearest to the far sensor.

The disadvantages of the considered methods of measuring the fluid flow rate in the well and devices for their implementation are the error in measuring the fluid flow rate with a change in the initial temperature of the well fluid flow and the instability of the heating power as the power source is discharged, leading to a decrease in the measurement accuracy.

SUMMARY OF THE INVENTION

The objective of the proposed group of inventions is to develop an autonomous downhole hot-wire anemometer of a new design, which ensures the accuracy of measuring parameters in the well.

The technical result of the group of inventions is to increase the accuracy of measurements.

The task and the required technical result are achieved through a new method for measuring the velocity of the fluid flow in the well, which consists in pulsed heating of the fluid flow, measuring the temperature of the fluid, at least two temperature sensors spaced along the axis of the well, and comparing signals, two temperature sensors, in which heating is carried out using pulse-width modulation, while in the process of measuring the temperature is recorded from the first sensor that measures the initial temperature in the sweat well of the borehole fluid, and from a second sensor measuring the temperature from the fluid heated by pulse-width modulation, and the velocity of the fluid flow in the well is determined by determining the difference in the measured temperatures from the first and second sensors, based on which, taking into account the initial temperature of the borehole flow fluid, calculated by the formula

V = V ₀ + a * ΔT + b * T + s * ΔT ² + d * T ² + f * ΔT * T,

where V ₀ , a, b, c, d, f are the coefficients calculated during calibration of the device in the operating temperature range;

T is the initial temperature of the flow of the well fluid;

ΔТ is the temperature difference between the heated and the initial flow of the well fluid.

The task and the required technical result are also achieved through a new autonomous downhole hot-wire anemometer for measuring the fluid flow rate in the well containing a power unit, a sealed cylindrical body, in the upper part of which there is a sealed compartment containing a computing system, and in the lower part along the body axis there is a through window of an oval section forming a cylindrical channel with two temperature sensors located inside it, located at opposite walls to the channel along the axis of the housing, and one of the temperature sensors contains a heater that performs heating using pulse-width modulation, and is located in the channel of the hot-wire anemometer above another temperature sensor.

Temperature sensors are placed in protective titanium casings.

The sealed compartment is arranged to accommodate microcontroller blocks, a modem for controlling the operation of the device, a heating block using pulse-width modulation and flash memory mounted on one chassis, the microcontroller block being electrically connected to other blocks.

The first temperature sensor is electrically connected to the microcontroller unit.

The second temperature sensor with a heater is electrically connected to the microcontroller unit.

The heater is made in the form of a nichrome spiral electrically connected to the heating unit.

The lower end of the housing is provided with a first adapter connector connected via a common bus to the computing system.

The upper end of the housing is equipped with a second adapter connector connected via a common bus to the computing system.

At the lower end of the housing is the first fairing, made with the possibility of rigid attachment to the lower part of the housing.

At the upper end of the housing is a power supply with a connector, made with the possibility of hard mounting its lower part to the housing so that the second adapter connector of the housing and the connector of the power supply are interconnected.

The power supply unit contains a battery electrically connected to the connector.

In the upper part of the power supply is a second fairing, made with the possibility of hard mounting to the power supply.

The first and second fairings are conical in shape, at the apex of each of which a through hole is perpendicular to the axis of the body

BRIEF DESCRIPTION OF THE DRAWINGS

The group of inventions will be better understood from the description, which is not restrictive and is given with reference to the accompanying drawings, in which:

In FIG. 1 is a longitudinal sectional view of an autonomous downhole hot-wire anemometer.

In FIG. 2 shows a longitudinal section through a power unit of an autonomous downhole hot-wire anemometer.

In FIG. 3 shows a diagram of a computing system of an autonomous downhole hot-wire anemometer.

DETAILED DESCRIPTION OF THE INVENTION

An autonomous downhole hot-wire anemometer with a power supply unit (9) contains a sealed cylindrical body (1), in the upper part of which there is a sealed compartment (5) containing a computer system, and in its lower part along the body axis (1) there is a through window (2) oval cross-section, forming a cylindrical channel with two temperature sensors located inside it (3, 4), located at opposite walls of the channel along the axis of the housing (1), one of the temperature sensors containing a heater that performs heating using latitudinal -pulse modulation, and is located in the channel of the hot-wire anemometer above another temperature sensor.

Temperature sensors (3, 4) are placed in protective titanium casings.

The sealed compartment (5) is arranged to accommodate microcontroller (14), modem (15) units for controlling the operation of the device, heating (16) using pulse-width modulation and flash memory (13) mounted on one base (chassis), moreover, the microcontroller block (15) is electrically connected to other blocks.

The first ambient temperature sensor (3) is electrically connected to the microcontroller unit.

The second heated temperature sensor (4) with a heater is electrically connected to the microcontroller unit.

The heater is made in the form of a nichrome spiral electrically connected to the heating unit.

The lower end of the housing (1) is equipped with a first adapter connector (6) connected via a common bus (17) to the computing system.

The upper end of the housing (1) is equipped with a second adapter connector (7) connected via a common bus (17) to the computing system.

At the lower end of the housing (1) is the first fairing (8), made with the possibility of rigid attachment to the lower part of the housing (1). The first cowling (11) contributes to better fluid flow around the device in the well.

At the upper end of the housing (1), there is a power supply (9) with a connecting connector (10), made with the possibility of hard fastening its lower part to the housing (1), so that the second adapter connector of the housing (7) and the connecting connector (10) ) of the power supply are interconnected.

The power supply unit contains a battery electrically connected to the connector.

In the upper part of the power supply (9) there is a second fairing (11), made with the possibility of hard mounting to the power supply (9).

The first (8) and second (11) fairings are conical in shape, at the apex of each of which a through hole (12) is perpendicular to the axis of the housing (1).

Autonomous downhole hot-wire anemometer works as follows.

A power supply unit (9) is connected to the upper part of the case (1) of the hot-wire anemometer so that the second adapter connector (7) of the case and the connecting connector (10) of the power supply are connected to each other, and the first fairing ( 8) using a threaded connection. Then, a second radome (11) is connected to the power supply unit (9) by means of a threaded connection. After that, a rope is connected to the through hole (12) of the second fairing (11) and lowered into the well, while the power of the computing system is provided by the battery in the power supply using a common bus (17).

After the device is placed in the borehole, the borehole fluid passes through the through-hole window (2) of the hot-wire anemometer, in which the fluid velocity is determined using temperature sensors (3, 4). To measure the fluid velocity in the borehole fluid, a signal is sent to the modem (15) to the microcontroller (14), which includes a heating unit and the heater heats the fluid in the borehole using pulse-width modulation. Thus, in the borehole fluid inside the through-hole (2), two regions are formed with different temperature of the borehole fluid. The first temperature sensor (3) measures the initial temperature in the well fluid stream, and the second temperature sensor (4) measures the temperature of the liquid heated by the heater. In the absence of flow, heat from the heater due to the thermal conductivity of the liquid and gravitational convection will be detected by both temperature sensors (3, 4), but since the second temperature sensor (4) is located closer to the heater, the temperature measured by it will be slightly higher than the temperature at the first temperature sensor (3). When the flow moves, the heat propagation rate increases due to forced convection. The higher the flow rate, the higher the heat loss and the lower the temperature recorded by the second temperature sensor (4). Data from temperature sensors (3, 4) is transferred to an analog-to-digital converter, where they are digitized, and then recorded on flash memory.

To analyze the recorded data from temperature sensors (3, 4), the hot-wire anemometer is removed from the well and the power supply unit (9) is disconnected from the hot-wire anemometer body (1), or the first fairing (8) from the hot-wire anemometer body (1). Then, an AMI bus connected to a personal computer is connected to the second adapter connector (7), or to the first adapter connector (6), in which a special program calculates the fluid velocity in the well based on the difference of the measured temperatures from the sensors (3, 4) and the readings the sensor (3) of the initial temperature in the flow of well fluid in accordance with the formula

V = V ₀ + a * ΔT + b * T + s * ΔT ² + d * T ² + f * ΔT * T,

where V ₀ , a, b, s, d, f are the coefficients calculated during calibration of the device in the operating temperature range;

T is the initial temperature of the flow of the well fluid;

ΔT is the temperature difference between the heated and the initial flow of the well fluid.

Coefficients V ₀ , a, b, c, d, f are selected empirically when calibrating the device, which consists in placing the device in a special stand and performing a series of measurements ΔT _i (the temperature difference of the heated temperature sensor and the ambient temperature sensor at the corresponding speeds and temperatures of the water flow ) at different temperatures of water and at different speeds of water flow with the subsequent determination of the coefficients V ₀ , a, b, c, d, f based on a system of linear equations:

where V _i is the water flow rate at the corresponding water temperature, T _i is the water flow temperature, ΔT _i is the temperature difference of the heated temperature sensor and the ambient temperature sensor at the corresponding speeds and temperatures of the water flow, n is the total number of values of the water flow temperature, speed water flow and the temperature difference of the heated temperature sensor and the ambient temperature sensor of the water obtained during the calibration of the device.

Calibration was carried out as follows. The device was placed in a special stand with a vertical pipe and water circulating in a closed circle, in which it is possible to heat water and adjust its speed in a closed circle. Measurements were carried out at various water flow rates (0.2, 1, 3, 4, 6, 7, 9 m / min) and heating water to temperatures of 30, 40, 50, 60 ° С. As a result, 28 measurements of ΔT _i values were carried out at each water flow rate and its temperature in accordance with the table:

In the table ΔТ ₁ is the temperature difference of the heated temperature sensor and the ambient temperature sensor at a water flow temperature of 30 ° C and a water flow rate of 0.2 m / min; ΔT ₂ - the temperature difference of the heated temperature sensor and the ambient temperature sensor at a water flow temperature of 40 ° C and a water flow rate of 0.2 m / min; ΔТ ₃ is the temperature difference of the heated temperature sensor and the ambient temperature sensor at a water flow temperature of 50 ° C and a water flow rate of 0.2 m / min, etc.

Based on the obtained values of 28 measurements of the device, the values of the coefficients V ₀ , а, b, с, d, f are determined based on the system of linear equations disclosed above, in which:

In addition, the first (7) and second (8) adapter connectors are designed for connection with other devices containing the corresponding sensors.

As experiments have shown, in comparison with the closest analogue, the application of the proposed method and an autonomous borehole hot-wire anemometer for measuring the flow rate of a fluid in a well improves the measurement accuracy due to the fact that when calculating the flow rate of a borehole fluid, the initial temperature of the flow of the borehole fluid is taken into account, which eliminates the error when the initial temperature of the well fluid flow changes, and also due to the use of heating using a pulse-width module This ensures stabilization of the heating power as the power source is discharged; as a result, when the voltage of the power source decreases, the duration of the heating pulse increases.

Although the proposed group of inventions has been disclosed in detail above with reference to specific embodiments that are preferred, it should be remembered that these embodiments are provided only to illustrate the invention. This description should not be construed as limiting the scope of the invention, since the steps of the described methods and devices by specialists in the field of physics, oil and gas industry, etc. may be amended to adapt them to specific devices or situations, and not beyond the attached claims. Specialist in this field it is clear that within the scope of the invention, which is defined by the claims, various options and modifications are possible, including equivalent solutions.

Claims (14)

1. The method of measuring the velocity of the fluid flow in the well, which consists in pulsed heating of the fluid flow, measuring the fluid temperature by at least two temperature sensors spaced along the axis of the well, and comparing the signals of the two temperature sensors, where the heating is carried out using pulse-width modulation, during the measurement process, the temperature is recorded from the first sensor that measures the initial temperature in the well fluid stream, and from the second sensor that measures the temperature from the heated with pulse-width modulation of the fluid and the velocity of fluid flow in the well is found by determining the difference of the measured temperatures with first and second sensors, on the basis of which, taking into account the initial temperature of the well fluid flow, produce calculation formula
V = V ₀ + a * ΔT + b * T + s * ΔT ² + d * T ² + f * ΔT * T,
where V ₀ , a, b, s, d, f are the coefficients calculated during calibration of the device in the operating temperature range;
T is the initial temperature of the flow of the well fluid;
ΔТ is the temperature difference between the heated and the initial flow of the well fluid. 2. An autonomous downhole hot-wire anemometer for implementing the method according to claim 1, comprising a power supply unit, a sealed cylindrical body, in the upper part of which there is a sealed compartment containing a computing system, and in its lower part along the body axis there is a through window of an oval section forming a cylindrical channel with two temperature sensors located inside it, located at opposite walls of the channel along the axis of the casing, one of the temperature sensors comprising a heater that heats and aid of pulse-width modulation, and stored in the channel above the other anemometer sensor. 3. The hot-wire anemometer according to claim 2, characterized in that the temperature sensors are placed in protective titanium casings. 4. The hot-wire anemometer according to claim 2, characterized in that the sealed compartment is arranged to accommodate microcontroller units, a modem for controlling the operation of the device, a heating unit using pulse-width modulation and flash memory mounted on one chassis, the microcontroller unit being electrically connected with other blocks. 5. The hot-wire anemometer according to claim 4, characterized in that the first temperature sensor is electrically connected to the microcontroller unit. 6. The hot-wire anemometer according to claim 4, characterized in that the second temperature sensor with a heater is electrically connected to the microcontroller unit. 7. The hot-wire anemometer according to claim 6, characterized in that the heater is made in the form of a nichrome spiral electrically connected to the heating unit. 8. The hot-wire anemometer according to claim 2, characterized in that the lower end of the housing is provided with a first adapter connector connected via a common bus to the computing system. 9. The hot-wire anemometer according to claim 1, characterized in that the upper end of the housing is equipped with a second adapter connector connected via a common bus to the computing system. 10. The hot-wire anemometer according to claim 8, characterized in that at the lower end of the housing there is a first fairing made with the possibility of rigid attachment to the lower part of the housing. 11. The hot-wire anemometer according to claim 9, characterized in that at the upper end of the housing there is a power supply unit with a connecting connector configured to rigidly fasten its lower part to the housing so that the second adapter connector of the housing and the connecting connector of the power supply are interconnected. 12. The hot-wire anemometer according to claim 11, characterized in that the power supply unit contains a battery electrically connected to the connector. 13. The hot-wire anemometer according to claim 9, characterized in that in the upper part of the power supply there is a second fairing made with the possibility of rigid attachment to the power supply. 14. The hot-wire anemometer according to claim 10, 13, characterized in that the first and second fairings are conical in shape, at the apex of each of which a through hole is perpendicular to the axis of the housing.

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