Downhole gas flow metering device, downhole gas flow calibration method and computer equipment

Abstract

The invention provides an underground gas flow metering device, an underground gas flow calibration method and computer equipment, and relates to the technical field of oil field testing, and the underground gas flow metering device comprises a flow metering assembly, a pressure metering assembly, a magnetic positioning assembly and a circuit assembly. The flow metering assembly adopts the thermal type gas flow metering principle, the temperature difference between the upper temperature probe and the lower temperature probe is adjusted through the heating assembly, and the gas flow change is accurately calculated according to the heating power change. The invention further provides an underground gas flow calibration method, the gas injection flow is divided into a plurality of steps, a plurality of monitoring points are arranged at different well depths, the pressure, temperature and heating assembly thermal power data of each monitoring point are recorded and compared with the wellhead injection flow, the flow metering value is corrected, and the flow metering accuracy is ensured. The problem that in the prior art, the underground gas flow metering error is large is solved, the production degree of a low-permeability reservoir is improved, and the oil well recovery efficiency can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oilfield testing, in particular to a downhole gas flow metering device, a downhole gas flow calibration method and a computer device. BACKGROUND

[0002] In the oilfield exploitation technology, the method of improving oil well recovery rate by injecting gas into the formation is increasingly valued. The gas drive oil recovery technology has achieved good results after years of development, but due to the difference in gas absorption capacity of the formation, the traditional full well combined injection method often cannot fully develop the potential of the reservoir. Therefore, the use of separate layer gas injection can better improve the recovery rate.

[0003] However, in order to monitor and measure the temperature, pressure and gas injection flow of the separate layers, downhole monitoring devices need to be used. At present, most downhole monitoring and metering devices are mainly used for liquid media, especially for the measurement of liquid flow. These devices usually use ultrasonic flowmeter, electromagnetic flowmeter, turbine flowmeter or orifice flowmeter technology, but they have limitations in downhole gas flow measurement:

[0004] Ultrasonic flowmeter: the circuit probe is complex and cannot work in a high temperature environment, and is only suitable for flow testing of water injection wells.

[0005] Electromagnetic flowmeter: although the measurement accuracy is high, the environmental adaptability is poor, there are specific requirements for the dielectric constant of the injected fluid, and the instrument cost is high.

[0006] Vortex flowmeter: only suitable for flow measurement of large flow media, although the circuit is simple, but the measurement accuracy is low.

[0007] The above flow metering devices have large errors (>40%) in downhole gas measurement, the main reason is that the temperature and pressure differences of gas at different wells and different depths will cause changes in gas volume and density, thereby affecting the measurement results.

[0008] In addition, the temperature and pressure environment of gas on the ground and in the well is significantly different, resulting in a large difference in gas density and volume, so ground calibration is not meaningful, and downhole calibration must be carried out to ensure the accuracy of separate layer gas injection flow measurement.

[0009] There is no device for accurate measurement of downhole gas flow and its supporting downhole flow calibration method in the prior art. It cannot solve the problems of uneven gas absorption profile, serious gas channeling in high permeability layers and low production in low permeability layers in general injection methods, and it is difficult to meet the needs of dynamic development of separate layer gas injection wells. SUMMARY

[0010] The present application aims to provide a downhole gas flow metering device, a downhole gas flow calibration method and a computer device, which can accurately meter and control the flow of each layer of a single well under different reservoirs and working conditions, and meet the needs of dynamic development of separate layer gas injection wells.

[0011] To achieve the above-mentioned purpose, the present application realizes the following technical solutions:

[0012] A downhole gas flow metering device comprises a flow metering assembly, a pressure metering assembly, a magnetic positioning assembly and a circuit assembly connected in sequence.

[0013] The flow metering assembly comprises a flow meter housing, an upper temperature probe, a lower temperature probe and a heating assembly, the flow meter housing is provided with a gas inlet and a gas outlet at two ends respectively, the upper temperature probe and the heating assembly are installed at the gas inlet, and the lower temperature probe is installed at the gas outlet.

[0014] Further, the pressure metering assembly comprises a pressure connector connected to the flow meter housing and a pressure sensor installed in the pressure connector.

[0015] Further, the magnetic positioning assembly comprises a magnetic positioning housing connected to the pressure metering assembly, and a coil skeleton, a high-strength magnetic steel and an inductor installed in the magnetic positioning housing. The magnetic positioning assembly plays a positioning role. The downhole gas flow meter can be positioned at a depth and a specific position by the magnetic positioning assembly. The inductor and the high-strength magnetic steel in the magnetic positioning assembly generate a magnetic field after the battery is powered on. The casing of the gas well is connected by a coupling. When the magnetic positioning assembly passes through the coupling, the magnetic field changes, thereby realizing positioning.

[0016] Further, the circuit assembly comprises a circuit housing connected to the magnetic positioning assembly, and a low-voltage power supply and a circuit board installed in the circuit housing. The circuit housing is provided with a cap at an end opposite to the magnetic positioning assembly.

[0017] Further, it further comprises an interface assembly, the interface assembly comprises an installation connector installed at one end of the flow metering assembly relative to the pressure metering assembly, and a single-core plug arranged in the installation connector.

[0018] The present application also provides a downhole gas flow calibration method, which applies the above-mentioned downhole gas flow metering device and comprises the following steps:

[0019] S1: The ground gas injection flow is divided into multiple steps;

[0020] S2: A plurality of monitoring points are set according to the well depth;

[0021] S3: Select the surface gas injection flow rate of one of the steps, connect the downhole gas flow metering device with a cable, and lower it to monitoring points at different depths in sequence, and measure and record the pressure, temperature and heating component thermal power data at each monitoring point;

[0022] S4: Read the data recorded in S3 and compare it with the wellhead injection flow rate to correct the flow rate measurement value; by comparing the recorded pressure, temperature and heating component thermal power data at the monitoring point with the wellhead injection flow rate, the flow rate measurement value is corrected to ensure the accuracy of flow rate measurement.

[0023] S5: Switch the surface gas injection flow rate of different steps, repeat steps S3-S4 until all steps are used up, and complete the calibration of the injection gas flow rate of this well.

[0024] Furthermore, the depth interval of the monitoring points is set to be 200m-400m.

[0025] Furthermore: the step setting range for the ground airflow volume is 500m. 3 / d-6000m 3 / d.

[0026] Furthermore, the number of steps in the ground airflow is 7-10.

[0027] The present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the above-described downhole gas flow rate calibration method.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] First, by adopting the principle of thermal gas flow measurement, that is, by adjusting the temperature difference between the upper and lower temperature probes through the heating component, and then accurately calculating the change in gas flow based on the change in heating power, the problem of large error in downhole gas flow measurement in the existing technology is solved.

[0030] Second, a downhole flow rate calibration method was proposed. By dividing the surface gas injection flow rate into multiple steps and setting multiple monitoring points at different well depths, the accuracy of the flow metering device at different flow rates and depths was ensured. This solved the problems of uneven gas intake profile, severe gas channeling in high-permeability layers and low utilization of low-permeability layers that exist in the general injection method. It further improved the utilization of low-permeability reservoirs and is conducive to improving oil well recovery rate. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of a downhole gas flow metering device according to Embodiment 1 of the present invention;

[0032] Figure 2 for Figure 1 A partially enlarged schematic diagram of the medium flow metering component;

[0033] Figure 3 for Figure 1 A partially enlarged schematic diagram of the medium pressure metering component and the magnetic positioning component;

[0034] Figure 4 for Figure 1 A partially enlarged schematic diagram of the circuit components;

[0035] Figure 5 This is a flowchart of a downhole gas flow rate calibration method in one embodiment;

[0036] Figure 6 This is a schematic diagram of the downhole flow step and measuring point setup in an embodiment of the present invention;

[0037] In the diagram: 1. Interface assembly; 1.1. Mounting connector; 1.2. Single-core plug; 2. Flow metering assembly; 2.1. Flow meter housing; 2.2. Upper temperature probe; 2.3. Lower temperature probe; 2.4. Heating assembly; 2.5. Gas inlet; 2.6. Gas outlet; 3. Pressure metering assembly; 3.1. Pressure connector; 3.2. Pressure sensor; 4. Magnetic positioning assembly; 4.1. Magnetic positioning housing; 4.2. Coil frame; 4.3. High-strength magnet; 4.4. Inductor; 5. Circuit assembly; 5.1. Circuit housing; 5.2. Low-voltage power supply; 5.3. Circuit board; 6. Protective cap. Detailed Implementation

[0038] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0040] Example 1:

[0041] like Figure 1As shown: A downhole gas flow metering device includes a flow metering component 2, a pressure metering component 3, a magnetic positioning component 4, and a circuit component 5 connected in sequence; it also includes an interface component 1, which includes a mounting connector 1.1 and a single-core plug 1.2 disposed in the mounting connector 1.1.

[0042] like Figure 2 As shown: The flow metering component 2 includes a flow meter housing 2.1, an upper temperature probe 2.2, a lower temperature probe 2.3, and a heating component 2.4. The flow meter housing 2.1 has a gas inlet 2.5 and a gas outlet 2.6 at its two ends, respectively. The upper temperature probe 2.2 and the heating component 2.4 are installed at the gas inlet 2.5, and the lower temperature probe 2.3 is installed at the gas outlet 2.6.

[0043] like Figure 3 As shown: The pressure metering assembly 3 includes a pressure connector 3.1 connected to the flow meter housing 2.1 and a pressure sensor 3.2 installed inside the pressure connector 3.1.

[0044] like Figure 3 As shown: The magnetic positioning assembly 4 includes a magnetic positioning housing 4.1 connected to the pressure gauge assembly, and a coil frame 4.2, a high-strength magnet 4.3 and an inductor 4.4 installed inside the magnetic positioning housing 4.1.

[0045] like Figure 4 As shown: Circuit assembly 5 includes a circuit housing 5.1 connected to the magnetic positioning assembly 4, and a low-voltage power supply 5.2 and a circuit board 5.3 installed inside the circuit housing 5.1. A protective cap 6 is installed on the end of the circuit housing 5.1 opposite to the magnetic positioning assembly 4.

[0046] This invention solves the problem of large gas flow measurement error in the prior art by adopting the principle of thermal gas flow measurement, that is, by adjusting the temperature difference between the upper and lower temperature probes 2.3 through the heating component 2.4, and then accurately calculating the change in gas flow based on the change in heating power.

[0047] In other embodiments, the present invention also provides a downhole gas flow rate calibration method, comprising the following steps:

[0048] S1: Divide the ground gas injection flow rate into multiple steps;

[0049] In some embodiments, the step size for the ground injection flow rate is set within a range of 500m. 3 / d-6000m 3 / d, the number of steps is 7-10, and in this embodiment, the preferred number of steps is 8.

[0050] S2: Set up multiple monitoring points according to the well depth;

[0051] In some embodiments, the depth interval of the monitoring points is 200m-400m, and in this embodiment, the preferred depth interval is 300m;

[0052] S3: Select the surface gas injection flow rate of one of the steps, connect the downhole gas flow metering device with a cable, and lower it to monitoring points at different depths in sequence. Measure and record the pressure, temperature, and heating component 2.4 thermal power data at each monitoring point.

[0053] S4: Read the data recorded in S3 and compare it with the wellhead injection flow rate to correct the flow rate measurement value; by comparing the recorded pressure, temperature and heating component 2.4 thermal power data at the monitoring point with the wellhead injection flow rate, the flow rate measurement value is corrected to ensure the accuracy of the flow rate measurement.

[0054] S5: Switch the surface gas injection flow rate of different steps, repeat steps S3-S4 until all steps are used up, and complete the calibration of the injection gas flow rate of this well.

[0055] The present invention also provides an implementation example of a downhole flow rate calibration method to illustrate the advantages of the present invention:

[0056] ① The flow rate is controlled at 500, 1000, 1500, 2000, 3000, 4000, 5000, and 6000 m³ / d, for a total of 8 flow rate steps. Pressure, temperature, and power counter monitoring points are controlled between 0 and 1200 m, with one monitoring point every 300 m, for a total of 5 monitoring points.

[0057] ② Connect the downhole gas flow metering device described in the above embodiment to the cable and lower it into the gas injection well. The first flow step (500m) 3 / d), at the wellhead location on the surface, start measuring the temperature, pressure, and thermal power count values ​​at that point. After the count values ​​stabilize or after continuous measurement for 20 minutes, the downhole gas flow metering device moves down to the second monitoring point (300m). After the count values ​​stabilize or after continuous measurement for 20 minutes, the downhole gas flow metering device moves down to the third monitoring point (600m)... until the last point (1200m) is measured, at which point the flow meter is raised to the wellhead.

[0058] ③ At the second flow step (1000 m3 / d), at the wellhead location on the surface, start measuring the temperature, pressure, and thermal power count values ​​at this point. After the count values ​​stabilize or after continuous measurement for 20 minutes, the downhole gas flow metering device moves down to the second monitoring point (300 m). After the count values ​​stabilize or after continuous measurement for 20 minutes, the downhole gas flow metering device moves down to the third monitoring point (600 m)... until the last point (1200 m) is measured, at which point the downhole gas flow metering device is raised to the wellhead.

[0059] ④ Repeat steps ② and ③ for the 3rd to 7th flow steps;

[0060] ⑤ After the eighth flow step (6000 m³ / d) is fixed on the surface and injected stably for 30 minutes, the temperature, pressure, and thermal power counts at the wellhead location on the surface are measured. Once the counts stabilize or after 20 minutes of continuous measurement, the downhole gas flow metering device is moved down to the second monitoring point (300 m). After the counts stabilize or after 20 minutes of continuous measurement, the device is moved down to the third monitoring point (600 m), and so on, until the last point (1200 m) is reached. The calibration of the downhole gas flow metering device is then completed, and it is raised to the wellhead. Specific flow steps and measuring points are as follows: Figure 6 As shown.

[0061] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A downhole gas flow metering device, characterized in that: It includes a flow metering component, a pressure metering component, a magnetic positioning component, and a circuit component connected in sequence; The flow metering assembly includes a flow meter housing, an upper temperature probe, a lower temperature probe, and a heating assembly. The flow meter housing has a gas inlet and a gas outlet at its two ends, respectively. The upper temperature probe and the heating assembly are installed at the gas inlet, and the lower temperature probe is installed at the gas outlet.

2. The downhole gas flow metering device according to claim 1, characterized in that: The pressure metering assembly includes a pressure connector connected to the flow meter housing and a pressure sensor installed inside the pressure connector.

3. The downhole gas flow metering device according to claim 1, characterized in that: The magnetic positioning assembly includes a magnetic positioning housing connected to the pressure gauge assembly, and a coil frame, a high-strength magnet, and an inductor installed inside the magnetic positioning housing.

4. The downhole gas flow metering device according to claim 1, characterized in that: The circuit assembly includes a circuit housing connected to the magnetic positioning component, and a low-voltage power supply and circuit board installed inside the circuit housing, with a protective cap installed on the end of the circuit housing opposite to the magnetic positioning component.

5. The downhole gas flow metering device according to claim 1, characterized in that: It also includes an interface component, which includes a mounting connector and a single-core plug disposed within the mounting connector, at one end of the flow metering component relative to the pressure metering component.

6. A method for calibrating downhole gas flow rate, characterized in that, The downhole gas flow metering device according to any one of claims 1-5 comprises the following steps: S1: Divide the ground gas injection flow rate into multiple steps; S2: Set up multiple monitoring points according to the well depth; S3: Select the surface gas injection flow rate of one of the steps, connect the downhole gas flow metering device with a cable, and lower it to monitoring points at different depths in sequence, and measure and record the pressure, temperature and heating component thermal power data at each monitoring point; S4: Read the data recorded in S3 and compare it with the wellhead injection flow rate to correct the flow rate measurement value; S5: Switch the surface gas injection flow rate of different steps, repeat steps S3-S4 until all steps are used up, and complete the calibration of the injection gas flow rate of this well.

7. The method for calibrating downhole gas flow rate according to claim 6, characterized in that: The depth interval of the monitoring points is set at 200m-400m.

8. The method for calibrating downhole gas flow rate according to claim 6, characterized in that: The step size for the ground airflow is set within a range of 500m. 3 / d-6000m 3 / d.

9. A method for calibrating downhole gas flow rate according to claim 8, characterized in that: The number of steps in the ground-based airflow is 7-10.

10. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, it implements the calibration method as described in any one of claims 6-9.

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