A steam injection well dryness logging device and method based on heat diffusion principle

Abstract

The present invention relates to logging instruments and methods used in the field of production logging during oilfield development, and in particular to a steam injection well dryness logging device and method based on the principle of heat diffusion. The device comprises a circuit tube, a current collecting umbrella driving device, a current collecting umbrella, a measuring sensor tube, and a sensor; the circuit tube is connected to the current collecting umbrella driving device, and the current collecting umbrella driving device controls the expansion and recovery of the current collecting umbrella; the lower end of the current collecting umbrella is connected to the sensor measuring tube, and the sensor measuring tube is installed with a sensor; the lower end of the current collecting umbrella driving device is provided with a steam inlet, and the lower end of the sensor measuring tube is provided with a steam outlet. The device of the present invention adopts a flow collection measurement method, and the steam-liquid two-phase flow satisfies the homogeneous flow model when flowing through the measuring sensor, reducing the influence of complex and variable flow patterns on the dryness measurement. Since the flow rate of the fluid flowing through the measuring sensor is increased after flow collection, accurate measurement of the downhole steam dryness of heavy oil steam injection wells can be achieved.

Description

Technical Field

[0001] The invention relates to a logging instrument and method used in the field of production logging in the process of oil field development, in particular to a steam injection well dryness logging device and method based on the principle of heat diffusion. Background Art

[0002] For oil wells that use steam injection for thermal recovery of heavy oil, it is necessary to measure the steam dryness at different depths along the wellbore from the wellhead to the steam injection layer above the wellbore to evaluate whether the steam injection effect meets the design requirements of the development plan. The steam injected into the steam injection string of the oil well is mostly saturated wet steam, which is a steam-liquid two-phase flow with liquid water and steam coexisting. The steam dryness is easily affected by factors such as ambient temperature, pressure and complex flow patterns and cannot be directly measured. Its accurate measurement has always been an international problem.

[0003] Chinese patent application CN107389749A discloses a downhole steam dryness measurement device, the device comprising: a steam-water separation unit; the steam-water separation unit comprises a cylindrical chamber, and a cylindrical measuring chamber located in the cylindrical chamber and coaxially arranged; the cylindrical chamber forms a separation annulus outside the cylindrical measuring chamber; a water electrode capacitance sensor probe; the water electrode capacitance sensor probe comprises a cylindrical metal core, and an insulating layer outside the cylindrical metal core; the cylindrical measuring chamber forms a measuring annulus outside the water electrode capacitance sensor probe; the upper end of the separation annulus is connected to the upper end of the measuring annulus; the lower end of the separation annulus is connected to the lower end of the measuring annulus; the water electrode capacitance sensor probe can form an equivalent capacitance sensor with the fluid in the measuring annulus; a capacitance meter for measuring the capacitance of the equivalent capacitance sensor. The downhole steam dryness measurement device provided by the present invention can realize online real-time measurement of dryness.

[0004] Chinese utility model patent CN205484157U discloses a steam dryness flow measurement device, including a main line, a temperature sensor 1, a flow meter, a homogenizer, a sampler, a resistance element, a return line, a flow regulating valve, a sampling flow measurement module, a temperature sensor 2, an insulation gasket 1, a heating module, an insulation gasket 2, a temperature sensor 3, a power regulation module, a PLC, and an insulation layer; the device adopts the principle of thermodynamics to realize the measurement of the dryness flow of wet hot steam in the pipeline.

[0005] Chinese patent application CN105588919A discloses a hot injection steam dryness test device and a dryness value calculation method thereof, the device comprises a condenser, a steam injection pipeline is connected to the condenser steam inlet, the condenser steam outlet is connected to the exhaust pipeline, the condenser cold water inlet is connected to the cooling water inlet pipeline, the condenser hot water outlet is connected to the cooling water outlet pipeline, and the pipelines are respectively provided with flow regulating valves, flow meters, thermometers, pressure gauges, etc. By testing the values ​​of various physical property parameters on the inlet and outlet pipelines of the condenser, the dryness value of the imported hot injection steam is obtained by analysis and calculation.

[0006] Among the domestic and foreign patents that have been published, the main methods for measuring steam dryness include capacitance method, thermal method, neutron density method, radioactive tracer method, acoustic method, and microwave method. According to the applicant's investigation of major heavy oil development fields in China, the method currently used for measuring downhole steam dryness in heavy oil steam injection wells at the oil field is mainly the method of downhole sampling and ground testing, which has low logging efficiency and success rate, and low dryness measurement accuracy. There is currently no steam dryness logging instrument and method that meets the needs of field logging applications. Summary of the invention

[0007] In order to solve the problem of online measurement of steam dryness in heavy oil steam injection wells, the present invention provides a steam injection well dryness logging instrument and method based on the principle of heat diffusion. The device of the present invention adopts a flow collection measurement method. When the steam-liquid two-phase flow passes through the measurement sensor, it satisfies the homogeneous flow model, which reduces the influence of complex and variable flow patterns on dryness measurement. Since the flow rate of the fluid flowing through the measurement sensor is increased after flow collection, the accurate measurement of steam dryness in heavy oil steam injection wells can be achieved.

[0008] The present invention adopts the following technical solutions:

[0009] The present invention provides a steam injection well dryness logging device based on the principle of heat diffusion, which comprises a circuit tube, a current collecting umbrella driving device, a current collecting umbrella, a measuring sensor tube and a sensor; the circuit tube is connected to the current collecting umbrella driving device, and the current collecting umbrella driving device controls the expansion and recovery of the current collecting umbrella; the lower end of the current collecting umbrella is connected to the sensor measuring tube, and the sensor measuring tube is installed with the sensor; the lower end of the current collecting umbrella driving device is provided with a steam inlet, and the lower end of the sensor measuring tube is provided with a steam outlet.

[0010] Preferably, the device has an outer diameter of 40 mm and an inner diameter of 28 mm; a dedicated circuit is installed in the circuit tube to supply power to the sensor and the current collecting umbrella driving device.

[0011] Preferably, the current collecting umbrella is a metal current collecting umbrella, which expands and closes the annular space between the instrument and the steam injection column when the instrument measures steam quality, forcing the steam-liquid two-phase flow to enter the sensor measuring cylinder connected to the lower end of the metal current collecting umbrella from the steam inlet.

[0012] Preferably, two groups of sensors are installed in the sensor measuring cylinder from top to bottom.

[0013] Further preferably, the distance between the two groups of sensors is 10 cm.

[0014] Further preferably, the first group of sensors are PT1000 armored cylindrical platinum resistance temperature sensors, which are used to measure the temperature of the mixed steam fluid.

[0015] Further preferably, the second group of sensors includes a ceramic substrate, a PT1000 platinum resistor, a PT40 platinum resistor and a measurement circuit.

[0016] The PT1000 platinum resistor is embedded in the center of the ceramic substrate, and the PT40 platinum resistor is embedded on the surface of the PT1000 platinum resistor. The PT1000 platinum resistor is completely covered and exposed to the flowing steam, and kept parallel to the steam flow direction. The heating resistor PT40 is exposed in the fluid to achieve rapid heat exchange and reach a thermal equilibrium state. The PT40 completely covers the PT1000 temperature measuring resistor, and the two groups of resistors fit closely, which improves the response sensitivity of the PT1000 to the temperature change of the PT40, thereby improving the measurement resolution and accuracy of the steam dryness. The measurement circuit and the first group of PT1000 (measuring the basic temperature of the fluid) and the second group of PT1000 (measuring the temperature change of the PT40) work together to correct the influence of the steam-liquid two-phase flow fluid temperature at different depths of the steam injection column on the steam dryness measurement.

[0017] Preferably, the ceramic substrate is a rectangular Al 2 O 3 Ceramic substrate.

[0018] The present invention also provides a method for measuring steam dryness using the above device, the method comprising the following steps:

[0019] The device is connected to the well with a steel wire; the collecting umbrella driving device in the circuit tube starts to work, so that the collecting umbrella expands and then stops working. The expanded collecting umbrella will completely close the annular flow space between the logging instrument and the steam injection pipe string, forcing the steam-liquid two-phase flow to enter the steam inlet and flow downward, flow through the sensor installed inside the measuring sensor tube, and finally flow back to the steam injection pipe string from the steam outlet at the lower end of the measuring sensor tube; the sensor starts to work and outputs the steam dryness; after the measurement is completed, the collecting umbrella driving device starts to work again to recycle the metal collecting umbrella, and stops working after the collecting umbrella is completely recovered.

[0020] Preferably, when the sensor is working, the measuring circuit provides 20W constant heating power for the second group of measuring sensors PT40 platinum resistors, and at the same time, the measuring circuit measures the temperature difference between the PT1000 platinum resistors of the first group of measuring sensors and the PT1000 platinum resistors of the second group of measuring sensors, and outputs and saves the temperature difference in the form of frequency through circuit conversion, and the output frequency represents the steam dryness.

[0021] The device of the present invention measures steam dryness based on the heat diffusion principle and the relationship between the heat exchange amount of the steam-liquid two-phase flow and the heat-generating component. The specific measurement principle is: the saturated wet steam injected into the steam injection column is a steam-liquid two-phase flow in which liquid water and steam coexist. Since the collective flow measurement method is adopted, the steam-liquid two-phase flow satisfies the homogeneous flow model when flowing through the measurement sensor. Assuming that a constant heating power W is provided for the mixed fluid, the volume flow rates of steam and liquid water are Q respectively. g and Q w , the density of steam and liquid water are ρ g and ρ w The constant pressure specific heat capacities of steam and liquid water are C pg and C pw , the temperature rise of the mixed fluid is ΔT, the steam quality is χ, according to the heat transfer principle, the heat released by PT40 in a certain period of time is equal to the heat taken away by the mixed fluid:

[0022]

[0023] From formula (1), the steam quality can be obtained as follows:

[0024]

[0025] Since the total mass flow rate in the steam injection column remains unchanged, the volume flow rate of steam and the volume flow rate of liquid water are related to the steam dryness. When the volume flow rate of steam and the volume flow rate of liquid water change, the degree of thermal diffusion of PT40 is different. The change of thermal diffusion of PT40 can be characterized by measuring its temperature change. Therefore, as long as the temperature rise change of PT40 is measured, the steam dryness can be indirectly measured.

[0026] Since the upper temperature limit of conventional logging cables is 175°C, they cannot be used in heavy oil steam injection wells. The measurement method described in the present invention does not require power supply through logging cables. A large-capacity high-temperature battery module is installed in the circuit tube of the logging instrument to power the logging instrument. Before the logging instrument is lowered into the wellbore for measurement, the circuit has been pre-designed on the ground, such as opening the collector at t1, measuring the dryness of the sensor at t2, and recovering the collector at t3. When measuring the dryness of heavy oil steam injection wells, it is only necessary to use steel wire to lower the logging instrument to a predetermined measurement depth. Since the underground ambient temperature of heavy oil steam injection wells exceeds the upper temperature limit of 150°C for most electronic components, the circuit tube part of the instrument is designed with a thermos bottle to ensure that the circuit can work normally under high temperature conditions in the external environment (using a thermos bottle is a common practice for designing high-temperature resistant logging instruments).

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] The device of the present invention adopts a flow collecting umbrella flow collecting measurement method. The gas-liquid two-phase flow satisfies the homogeneous flow model when flowing through the measuring sensor, reducing the influence of complex and variable flow patterns on dryness measurement. Since the flow rate of the fluid flowing through the measuring sensor is increased after flow collection, the dryness measurement problem of low injection volume wells is further solved.

[0029] The device of the present invention has a wide measuring range and high sensitivity, the steam dryness range is 0-98.0%, and the measuring accuracy can reach ±3%. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0031] Figure 1 This is a schematic diagram of a steam quality logging instrument based on the heat diffusion principle according to a specific embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of a sensor according to a specific embodiment of the present invention;

[0033] Figure 3 This is a calibration chart for a steam quality logging instrument according to a specific embodiment of the present invention. DETAILED DESCRIPTION

[0034] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0035] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations and / or combinations thereof.

[0036] Example 1

[0037] The steam injection well dryness logging device based on the principle of thermal diffusion includes: a circuit tube, a metal current collecting umbrella driving device, a metal current collecting umbrella, a measuring sensor tube, and a sensor; the circuit tube is connected to the metal current collecting umbrella driving device, and the metal current collecting umbrella driving device controls the expansion and recovery of the metal current collecting umbrella; the lower end of the metal current collecting umbrella is connected to the sensor measuring tube, and two groups of sensors are installed in the sensor measuring tube; a steam inlet is provided at the lower end of the metal current collecting umbrella driving device, and a steam outlet is provided at the lower end of the sensor measuring tube 5.

[0038] The device has an outer diameter of 40 mm and an inner diameter of 28 mm. A dedicated circuit is installed in the circuit tube to supply power to the sensor and the current collecting umbrella driving device.

[0039] The distance between the two sets of sensors is 10cm.

[0040] The first set of sensors is a PT1000 armored cylindrical platinum resistance temperature sensor, which is used to measure the temperature of the mixed steam fluid. The second set of sensors includes a rectangular Al 2 O 3 Ceramic substrate, PT1000 platinum resistor, PT40 platinum resistor and measuring circuit; the PT1000 platinum resistor is embedded in the center of the ceramic substrate, the PT40 platinum resistor is embedded on the surface of the PT1000 platinum resistor, and the PT1000 platinum resistor is completely covered and both ends of the PT40 platinum resistor are exposed in the flowing steam and kept parallel to the steam flow direction.

[0041] Example 2

[0042] like Figure 1As shown, the steam injection well dryness logging device based on the thermal diffusion principle includes: a circuit tube 1, a metal current collecting umbrella driving device 2 is connected below the circuit tube 1, the metal current collecting umbrella driving device 2 controls the expansion and recovery of the metal current collecting umbrella 4, the lower end of the metal current collecting umbrella driving device 2 is a steam inlet 3, the function of the metal current collecting umbrella 4 is to expand the annular space between the closed instrument and the steam injection pipe column when the device performs steam dryness measurement, forcing the steam-liquid two-phase flow to enter the sensor measuring tube 5 connected to the lower end of the metal current collecting umbrella 4 from the steam inlet 3, and the sensor measuring tube 5 is installed with two groups of measuring sensors 6 and 7 from top to bottom. The first group of measuring sensors 6 is a PT1000 armored cylindrical platinum resistance temperature sensor, which is used to measure the temperature of the mixed steam fluid. The cylindrical wall thickness is 4mm and can withstand a pressure of 40MPa; the distance between the second group of measuring sensors 7 and the first group of measuring sensors 6 is 10cm, as shown in FIG. Figure 2 As shown, this set of sensors uses a rectangular high-temperature resistant Al2O3 with a length of 6 mm, a width of 10 mm, and a thickness of 4 mm. 2 O 3 Ceramic substrate, firstly, a PT1000 platinum resistor (temperature measuring resistor, measuring the temperature change of PT40 platinum resistor) with a length of 2mm, a width of 2mm and a thickness of 1mm is embedded in the center of the surface of the rectangular ceramic base; then a PT40 platinum resistor (heating resistor) with a length of 3mm, a width of 3mm and a thickness of 1mm is embedded on the outer surface of PT1000. PT40 will completely cover PT1000. PT40 is exposed to the flowing steam in the measuring pipe (this design can ensure the rapid exchange of heat generated by PT40 with the flowing steam, and improve the measurement sensitivity of the sensor), and keep it parallel to the steam flow direction. The lower end of the sensor measuring tube 5 is the steam outlet 8.

[0043] The device has an outer diameter of 40 mm and an inner diameter of 28 mm.

[0044] Example 3

[0045] The steam dryness measurement method is performed using the device described in Example 2:

[0046] (1) The device is lowered into the steam injection pipe column to a predetermined depth by a steel wire;

[0047] (2) At time t1, the driving circuit of the metal current collecting umbrella driving device 2 in the circuit tube 1 starts to work, and the metal current collecting umbrella driving device 2 will expand the metal current collecting umbrella 4; the metal current collecting umbrella 4 will completely close the annular flow space between the logging instrument and the steam injection string, forcing the steam-liquid two-phase flow to enter the steam inlet 3 and flow downward, flow through the two groups of measuring sensors installed in the measuring sensor tube 5, and finally flow back to the steam injection string from the steam outlet 8 at the lower end of the measuring sensor tube 5. After the expansion of the metal current collecting umbrella is completed, the driving circuit of the metal current collecting umbrella driving device 2 in the circuit tube 1 stops working.

[0048] (3) At time t2, the measuring circuit of the sensor starts to work. The measuring circuit provides 20W constant heating power to the PT40 platinum resistor of the second group of measuring sensors 7. At the same time, the measuring circuit measures the temperature difference between the PT1000 platinum resistor of the first group of measuring sensors 6 and the PT1000 platinum resistor of the second group of measuring sensors 7. The temperature difference is converted by the circuit and output in the form of frequency. The output frequency represents the steam dryness.

[0049] (4) At time t3, the driving circuit of the metal current collecting umbrella driving device 2 starts to work again, and the metal current collecting umbrella driving device 2 will recycle the metal current collecting umbrella 4 until the metal current collecting umbrella 4 is completely recycled, and then the driving circuit of the metal current collecting umbrella driving device 2 stops working.

[0050] Example 3 completes the measurement of steam quality at a predetermined depth; if there are multiple depths in a well where the steam quality needs to be measured, it is only necessary to design the circuit in advance before the instrument is lowered into the well so that the current collecting umbrella is repeatedly opened and recovered at multiple times, and the measurement circuit of the sensor can also perform multiple measurements.

[0051] The actual calibration was carried out in a steam injection simulation well on site. The injection rate of the well was 192.00 t / d, and the boiler outlet dryness was adjusted in the range of 0 to 98.0%. The device described in Example 2 was used to carry out actual measurement and calibration at a depth of 20 m from the wellhead in the steam injection column. The calibration chart is shown in FIG. Figure 3 As shown, the device can measure the steam dryness in the range of 0 to 98.0%, and the dryness measurement accuracy is ±3%.

[0052] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A steam injection well dryness logging device based on the principle of heat diffusion, characterized in that: It includes a circuit tube, a current collecting umbrella driving device, a current collecting umbrella, a measuring sensor tube, and a sensor; The circuit cylinder is connected to the current collecting umbrella driving device, and the current collecting umbrella driving device controls the expansion and recovery of the current collecting umbrella; the lower end of the current collecting umbrella is connected to the sensor measuring cylinder, and the sensor measuring cylinder is equipped with a sensor; A steam inlet is provided at the lower end of the collecting umbrella driving device, and a steam outlet is provided at the lower end of the sensor measuring tube; Two groups of sensors are installed from top to bottom in the sensor measuring tube, and the distance between the two groups of sensors is 10 cm. The first group of sensors is a PT1000 armored cylindrical platinum resistance temperature sensor, which is used to measure the temperature of the mixed steam fluid. The second group of sensors includes a ceramic substrate, a PT1000 platinum resistor, and a PT40 platinum resistor. The PT1000 platinum resistor is embedded in the center of the ceramic substrate, and the PT40 platinum resistor is embedded on the surface of the PT1000 platinum resistor. The PT1000 platinum resistor is completely covered and both ends of the PT40 platinum resistor are exposed in the flowing steam and kept parallel to the steam flow direction. The device is connected to the well with a steel wire. The collector umbrella driving device in the circuit tube starts to work, so that the collector umbrella stops working after expansion, and the expanded collector umbrella will be completely closed. The annular flow space between the logging instrument and the steam injection string forces the steam-liquid two-phase flow to enter the steam inlet and flow downward, flowing through the sensor installed inside the measuring sensor tube, and finally flowing back to the steam injection string from the steam outlet at the lower end of the measuring sensor tube; the sensor starts working and outputs the steam dryness; after the measurement is completed, the collecting umbrella driving device starts working again to recycle the metal collecting umbrella, and stops working after the collecting umbrella is recovered; when the sensor is working, the measuring circuit provides 20W constant heating power for the second group of measuring sensor PT40 platinum resistors, and at the same time, the measuring circuit will measure the temperature difference between the PT1000 platinum resistors of the first group of measuring sensors and the PT1000 platinum resistors of the second group of measuring sensors, and output and save the temperature difference in the form of frequency through circuit conversion, and the output frequency represents the steam dryness.

2. The device according to claim 1, characterized in that: The device has an outer diameter of 40 mm and an inner diameter of 28 mm. A dedicated circuit is installed in the circuit tube to supply power to the sensor and the current collecting umbrella driving device.

3. The device according to claim 1, characterized in that: The current collecting umbrella is a metal current collecting umbrella.

4. The device according to claim 1, characterized in that: The ceramic substrate is a rectangular Al2O3 ceramic substrate.

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