CN106979005B - Working fluid level height sensor suitable for gas-liquid two-phase flow and use method thereof - Google Patents

Abstract

The invention provides a dynamic liquid level sensor suitable for gas-liquid two-phase flow, which includes a sealing head, a sealing seat, an outer shell and a base connected in sequence, and the dynamic liquid level sensor also includes a wire, a circuit board, an air bubble Probes, temperature probes and strain gauges, the circuit board, air bubble probes and temperature probes are all located in the housing, the strain gauges are located in the base, one end of the wire, bubble probes, strain gauges and temperature probes are respectively connected to The circuit board is connected, and the other end of the wire is connected to a terminal device. The present invention also provides a method for using the dynamic liquid level sensor, which includes the following steps: lowering the oil pipe installed with the dynamic liquid level sensor below the downhole dynamic liquid level to obtain the first height and the pressure of the wellhead air ; Input the first height and the pressure of the wellhead air to the terminal equipment; measure and obtain the fluid pressure and fluid average density; calculate the dynamic liquid level height. The invention can measure the dynamic liquid level height in real time.

Description

A dynamic liquid level sensor suitable for gas-liquid two-phase flow and its application method

technical field

The invention relates to the technical field of coalbed methane detection, in particular to a dynamic liquid level sensor suitable for gas-liquid two-phase flow and a use method thereof.

Background technique

my country is rich in coalbed methane reserves, among which the coalbed methane resources with a buried depth of less than 2000 meters are 36.81 trillion cubic meters, accounting for about 15.3% of the world's total, and the reserves rank third in the world. In order to make full use of coalbed methane resources, the Chinese government has intensified the research and development of coalbed methane mining technology in recent years, and drilled a number of test wells to explore the complete set of technologies for coalbed methane mining. However, limited by technical conditions, my country's coalbed methane Most of the gas production wells are vertical wells.

For coalbed methane mining, due to the natural fracture development structure of coal reservoirs, coalbed methane production wells need to be drained and depressurized. Gas-liquid two-phase flow, which leads to the increase of the liquid level in the annulus of the wellbore; the CBM infiltrated into the annulus of the wellbore exists in the form of bubbles or gas columns and rises along the wellbore, and the rising CBM will eventually break away from the liquid surface of the annulus of the wellbore , resulting in a decrease in the dynamic fluid level in the wellbore annulus; in addition, factors such as formation water gushing and water leakage will also cause changes in the dynamic fluid level in the wellbore annulus. Therefore, due to the existence of the above-mentioned many complicated factors, the height of the dynamic liquid level in the wellbore annulus is dynamically changed, thus forming the dynamic liquid level.

For vertical wells, the height of the dynamic liquid level in the wellbore annulus is one of the important parameters for formulating the drainage process, so it is necessary to measure the height of the dynamic liquid level in real time. Common oil and gas well liquid level measurement methods include buoy measurement, echo Detection method and pressure detection method, etc., but the above common methods cannot meet the needs of real-time measurement of liquid level in coalbed methane drainage wells due to many problems such as installation problems, design problems, potential safety hazards, measurement accuracy and inability to measure in real time.

Contents of the invention

In view of this, the present invention provides a dynamic liquid level sensor suitable for gas-liquid two-phase flow that can measure the dynamic liquid level height in real time and improve the measurement accuracy, and also provides a dynamic liquid level sensor that uses the dynamic liquid level sensor to measure the dynamic liquid level. Liquid level method.

The invention provides a dynamic liquid level sensor suitable for gas-liquid two-phase flow, the dynamic liquid level sensor includes a sealing head, a sealing seat, an outer shell and a base connected in sequence, and the dynamic liquid level sensor also includes a wire , a circuit board, an air bubble probe, a temperature probe and a strain gauge, the circuit board, the air bubble probe and the temperature probe are located in the housing, the strain gauge is located in the base, the wires, the air bubble probe, the temperature probe and the strain gauge The sheets are respectively connected to the circuit board, the bubble probe is used to obtain the average density of the fluid, the strain gauge is used to measure the fluid pressure, the temperature probe is used to measure the temperature, and the temperature measured by the temperature probe corresponds to the strain The pressure measured by the gauge is corrected to eliminate the temperature drift of the strain gauge.

Further, the outer casing includes an upper end of the outer casing and a lower end of the outer casing, the sealing head is threadedly connected to the upper end of the sealing seat, the lower end of the sealing seat is threaded to the upper end of the outer casing, and the lower end of the outer casing is threaded to the base , the joint between the seal head and the seal seat is provided with a first rubber ring, the upper end of the seal seat is provided with a first groove for placing the first rubber ring, and the joint between the upper end of the outer casing and the seal seat is provided There is a gasket, the upper end of the outer casing is provided with a second groove for placing the gasket, the connection between the lower end of the outer casing and the base is provided with a rubber sealing ring, the lower end of the outer casing is stepped, and the The rubber sealing ring is placed on the stepped step at the lower end of the outer casing.

Further, one end of the wire passes through the central hole of the sealing head, the first rubber ring and the sealing seat in order to be connected to the circuit board, and the first rubber ring is compressed at the joint of the sealing head and the sealing seat, so that the The first rubber ring clings to the wire to seal the wire, and the other end of the wire is connected to the terminal device.

Further, the inside of the outer casing is connected with a card holder, and the holder is threadedly connected with the inside of the outer casing, and a first threaded blind hole is processed on the holder, and a first through hole is provided on the circuit board , the circuit board can be fixed on the holder by inserting bolts in the first through hole and the first threaded blind hole, and the end surface of the holder is processed with an inner hexagonal groove to facilitate unscrewing with an inner hexagonal wrench .

Further, a gland is connected to the outer casing, a second rubber ring is provided at the connection between the outer casing and the gland, and a third groove for placing the second rubber ring is provided on the outer casing, The outer casing is processed with a second threaded blind hole and a second through hole, and the air bubble probe passes through the gland, the center hole of the second rubber ring and the second through hole in turn and is connected to the circuit board. The cover is provided with a third through hole, and the gland can be fixedly connected to the outer casing by inserting screws in the third through hole and the second threaded blind hole, and at the same time, the gland compresses the second rubber ring to achieve alignment. Bubble probe seal.

Further, a protective cover is also connected to the outer casing, the protective cover is located above the gland, and a fourth through hole is provided on the protective cover, through inserting into the fourth through hole and the second threaded blind hole The screw can fix the protective cover on the outer casing, and the protective cover is used to protect the air bubble probe.

Further, a fourth groove is processed in the base, and a strain gauge with a waterproof function is placed in the fourth groove, and a pressure ring is arranged above the strain gauge, and the pressure ring is located between the deck and the shell. The joint inside the body, the pressure ring is used to seal the strain gauge.

Further, a third threaded blind hole is processed on the circuit board, and the temperature probe is screwed into the third threaded blind hole through threaded connection, thereby connecting the temperature probe to the circuit board, and the circuit board is connected The data processing circuit is used for processing the data detected by the strain gauge, the air bubble probe and the temperature probe.

The present invention also provides a method for using a dynamic liquid level sensor suitable for gas-liquid two-phase flow, comprising the following steps:

Install the dynamic fluid level height sensor on the tubing, and then lower the tubing installed with the dynamic fluid level height sensor below the downhole dynamic fluid level to obtain the first height, which is the first height for which the dynamic fluid level sensor is installed. The depth of the position from the wellhead, and at the same time obtain the pressure of the wellhead air;

inputting the first altitude and the pressure of the wellhead air to a terminal;

Start the dynamic liquid level sensor, use the strain gauge to measure the fluid pressure at the installation position of the dynamic liquid level sensor, and use the bubble probe to obtain the average value of the fluid between the dynamic liquid level sensor installation position and the dynamic liquid level Density, the fluid pressure and average density are transmitted to the terminal equipment;

The terminal device processes the received fluid pressure and average density to obtain the fluid level height.

Further, the height of the dynamic liquid level is specifically obtained through the following steps:

Calculate the pressure generated by the liquid at the installation position of the dynamic liquid level sensor, and the calculation formula for the pressure generated by the liquid at the installation position of the dynamic liquid level sensor is:

P ₂ =P ₁ -P ₀

In the formula, _P2 is the pressure generated by the liquid at the installation position of the dynamic liquid level sensor, _P1 is the fluid pressure at the installation position of the dynamic liquid level sensor measured by the strain gauge, and _P0 is the pressure of the wellhead air;

Calculate the second height, the second height is the depth of the moving liquid level from the installation position of the moving liquid level height sensor, and the calculation formula of the second height is:

h ₂ =P ₂ /ρg

In the formula, _h2 is the second height, ρ is the average density obtained by using the bubble probe, and g is the gravitational constant;

Calculate the height of the dynamic liquid level, the calculation formula of the height of the dynamic liquid level is:

h ₃ =h ₁ -h ₂

In the formula, h ₃ is the height of the liquid level, and h ₁ is the first height.

The beneficial effects brought by the technical scheme provided by the invention are:

1. The dynamic liquid level sensor provided by the present invention has a simple structure and is easy to install. The present invention arranges a first rubber ring at the junction of the sealing head and the sealing seat, and sets a gasket at the junction of the upper end of the outer shell and the sealing seat. A rubber sealing ring is set at the connection between the lower end of the outer shell and the base, which effectively ensures the sealing of the dynamic liquid level sensor and reduces potential safety hazards;

2. In the present invention, the first rubber ring is used to seal the wire, the second rubber ring is used to seal the air bubble probe, and the protective cover is used to protect the air bubble probe, and the pressure ring is used to seal the strain gauge to avoid the height of the dynamic liquid level. The sensor is affected by fluid flow;

3. The present invention corrects the pressure measured by the strain gauge through the temperature probe, which can effectively eliminate the temperature drift of the strain gauge. The present invention uses the bubble probe to obtain the average density of the fluid, and reduces the pressure caused by the influence of the foam section in the annulus of the wellbore. The error effectively solves the problem that the existing measurement method has a large error in measuring the dynamic liquid level height of the bubble-containing section, and improves the measurement accuracy of the dynamic liquid level height;

4. The method of use provided by the present invention has simple steps, is convenient for calculation, and can realize real-time measurement of the dynamic liquid level height.

Description of drawings

Fig. 1 is a front view of a dynamic liquid level sensor suitable for gas-liquid two-phase flow according to the present invention.

Fig. 2 is a right side view of a dynamic liquid level sensor suitable for gas-liquid two-phase flow according to the present invention.

Fig. 3 is a top view of a dynamic liquid level sensor suitable for gas-liquid two-phase flow according to the present invention.

Fig. 4 is a schematic cross-sectional view of a dynamic liquid level sensor suitable for gas-liquid two-phase flow according to the present invention.

Fig. 5 is a top view of a deck of a dynamic liquid level sensor suitable for gas-liquid two-phase flow according to the present invention.

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention clearer, the embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

Please refer to FIG. 1 to FIG. 5 , the embodiment of the present invention provides a dynamic liquid level sensor suitable for gas-liquid two-phase flow, which includes a sealing head 1, a sealing seat 2, an outer shell 3 and a base 4 connected in sequence , the outer casing 3 includes an upper end 31 of the outer casing and a lower end 32 of the outer casing, the upper end 31 of the outer casing and the lower end 32 of the outer casing are processed with threads, the sealing head 1 is threadedly connected with the upper end of the sealing seat 2, and the lower end of the sealing seat 2 is connected with the upper end of the outer casing 31 threaded connection, the lower end 32 of the outer casing is threaded with the base 4, the joint between the sealing head 1 and the sealing seat 2 is provided with a first rubber ring 22, and the upper end of the sealing seat 2 is provided with a first concave for placing the first rubber ring 22 Groove 21, the shape of the first groove 21 is conical, the joint of the upper end 31 of the outer shell and the sealing seat 2 is provided with a gasket 312, and the joint of the upper end 31 of the outer shell and the sealing seat 2 can be sealed by the sealing gasket 312 , the upper end 31 of the outer casing is provided with a second groove 311 for placing a gasket 312, and a rubber sealing ring 321 is provided at the connection between the lower end 32 of the outer casing and the base 4, and the lower end 32 of the outer casing can be connected to the base by the rubber sealing ring 321. 4 is sealed, the lower end 32 of the outer shell is stepped, and the rubber sealing ring 321 is placed on the stepped step of the lower end 32 of the outer shell. In one embodiment, the rubber sealing ring 321 is an O-ring.

The dynamic liquid level sensor also includes a wire 5, a circuit board 6, an air bubble probe 7, a temperature probe 8 and a strain gauge 9. The circuit board 6, the air bubble probe 7 and the temperature probe 8 are all located in the outer casing 3, and the wire 5 One end passes through the central hole of the sealing head 1, the first rubber ring 22 and the sealing seat 2 in order to connect with the circuit board 6, and the first rubber ring 22 is compressed at the joint of the sealing head 1 and the sealing seat 2, so that the first The rubber ring 22 is tightly attached to the wire 5 to seal the wire 5 , and the other end of the wire 5 is connected to a terminal device 101 .

The bubble probe 7 is used to obtain the average density of the fluid, the strain gauge 9 is used to measure the fluid pressure, the temperature probe 8 is used to measure the temperature, and the temperature measured by the temperature probe 8 is used to correct the pressure measured by the strain gauge 9, thereby eliminating The temperature drift of the strain gauge 9.

The interior of the outer casing 3 is connected with a card seat 33, and the card seat 33 is threadedly connected with the interior of the outer casing 3. The card seat 33 is processed with a first threaded blind hole 331, and the circuit board 6 is provided with a first through hole 61. Inserting bolts into the first through hole 61 and the first threaded blind hole 331 can fix the circuit board 6 on the clamping seat 33 .

Please refer to FIG. 5 , the end surface of the card holder 33 is processed with an inner hexagonal groove 332 to facilitate unscrewing with an inner hexagonal wrench.

A gland 352 is fixedly connected to the outer shell 3, a second rubber ring 351 is provided at the connection between the outer shell 3 and the gland 352, and a third groove 35 for placing the second rubber ring 351 is provided on the outer shell 3, The outer casing 3 is also processed with a second threaded blind hole 34 and a second through hole 36, and the air bubble probe 7 passes through the gland 352, the center hole of the second rubber ring 351 and the second through hole 36 in turn, and connects with the circuit board 6 connection, the gland 352 is provided with a third through hole 3521, and the gland 352 can be fixedly connected to the outer shell 3 by inserting screws in the third through hole 3521 and the second threaded blind hole 34, and the gland 352 connects the first The two rubber rings 351 are compressed so as to realize the sealing of the air bubble probe 7 .

A protective cover 353 is also fixedly connected to the outer shell 3, and the protective cover 353 is located above the gland 352. The protective cover 353 is provided with a fourth through hole 3531, which is inserted into the fourth through hole 3531 and the second threaded blind hole 34. The screw can fix the protective cover 353 on the outer casing 3 , and the protective cover 353 is used to protect the air bubble probe 7 .

Please refer to FIG. 4 , a third threaded blind hole 62 is processed on the circuit board 6 , and the temperature probe 8 is screwed into the third threaded blind hole 62 through threaded connection, thereby connecting the temperature probe 8 to the circuit board 6 .

A fourth groove 41 is processed in the base 4, and a strain gauge 9 with a waterproof function is placed in the fourth groove 41. The strain gauge 9 is connected to the circuit board 6, and a pressure ring 333 is arranged above the strain gauge 9. The pressure ring 333 is located at the connection between the clamping seat 33 and the inside of the outer casing 3 , and is used for sealing the strain gauge 9 .

A data processing circuit 63 is connected to the circuit board 6 , and the data processing circuit 63 is used for processing the data detected by the strain gauge 9 , the air bubble probe 7 and the temperature probe 8 .

The working principle of the dynamic liquid level sensor is: the strain gauge 9 is deformed by the pressure of the gas-liquid two-phase flow in the annulus of the wellbore, the greater the pressure, the greater the deformation, and there is a linear relationship between the pressure value and the deformation The pressure value of the fluid can be obtained by calibrating the deformation of the strain gauge 9. At the same time, since the strain gauge 9 is sensitive to temperature, it is easy to cause temperature drift. Therefore, the temperature probe 8 is used to measure the temperature in real time. According to the temperature measurement result, the The temperature drift of the strain gauge 9 is corrected, and the data measured by the strain gauge 9 and the temperature probe 8 are transmitted to the data processing circuit 63, and the data processing circuit 63 can process the data; If a general density sensor is used for measurement, the measurement result is the liquid density, and the average density after the liquid and gas are mixed cannot be obtained. The gas-liquid two-phase flow is divided into different flow patterns according to the gas content. The flow pattern of the fluid There is a corresponding relationship with the fluid density. The parameter data of the fluid can be detected in real time by using the bubble probe 7, and the parameter data is transmitted to the data processing circuit 63. The data processing circuit 63 judges the flow pattern of the fluid through calculation. The result is the average density of the liquid mixed with the gas.

Embodiments of the present invention also provide a method for using a dynamic liquid level sensor: comprising the following steps:

S101, install the dynamic fluid level sensor on the tubing, and then lower _the tubing with the dynamic fluid level sensor installed under the downhole dynamic fluid level to obtain the first height h ₁ , which is the dynamic fluid level height The sensor installation position is the depth from the wellhead, and the pressure P ₀ of the wellhead air is obtained at the same time.

S102, input the first height h ₁ and the pressure P ₀ of the wellhead air to the terminal device 101;

S103, start the dynamic liquid level sensor, use the strain gauge 9 to measure the fluid pressure P ₁ at the installation position of the dynamic liquid level sensor, and use the bubble probe 7 to obtain the fluid between the dynamic liquid level sensor installation position and the dynamic liquid level The average density ρ, the fluid pressure P ₁ and the average density ρ are transmitted to the terminal device 101;

S104, the terminal device 101 processes the received fluid pressure P ₁ and the average density ρ to obtain the dynamic fluid surface height h ₃ ;

The dynamic liquid level height _h3 is specifically obtained through the following steps:

4.1 Calculate the pressure P ₂ generated by the liquid at the installation position of the dynamic liquid level sensor, and the calculation formula for the pressure P ₂ generated by the liquid at the installation position of the dynamic liquid level sensor is:

P ₂ =P ₁ -P ₀ ;

4.2 Calculate the second height h ₂ , the second height h ₂ is the depth from the moving liquid level to the installation position of the moving liquid level height sensor, the calculation formula of the second height h ₂ is:

h ₂ =P ₂ /ρg

In the formula, ρ is the average density obtained by using the bubble probe 7, and g is the gravitational constant;

4.3 Calculation of the dynamic liquid level height h ₃ , the calculation formula of the dynamic liquid level height h ₃ is:

h ₃ =h ₁ −h ₂ .

The dynamic liquid level sensor provided by the present invention is simple in structure and easy to install. The present invention arranges the first rubber ring 22 at the junction of the sealing head 1 and the sealing seat 2, and sets a sealing ring 22 at the junction of the upper end 31 of the outer shell and the sealing seat 2. Pad 312, a rubber sealing ring 321 is set at the connection between the lower end 32 of the outer casing and the base 4, which effectively ensures the sealing of the dynamic liquid level sensor and reduces potential safety hazards; For sealing, the second rubber ring 351 is used to seal the air bubble probe 7, and at the same time, the protective cover 353 is used to protect the air bubble probe 7, and the pressure ring 333 is used to seal the strain gauge 9, so as to prevent the dynamic liquid level sensor from being affected by the fluid flow; The present invention uses the temperature probe 8 to correct the pressure measured by the strain gauge 9, which can effectively eliminate the temperature drift of the strain gauge 9. The present invention uses the bubble probe 7 to obtain the average density of the fluid, reducing the pressure caused by the foam section in the wellbore annulus. The error caused by the existing measurement method effectively solves the problem that the existing measurement method has a large error in measuring the height of the dynamic liquid level of the bubble-containing section, and improves the measurement accuracy of the height of the dynamic liquid level; the method of use provided by the invention has simple steps, is convenient for calculation, and can Real-time measurement of the dynamic liquid level height.

In this article, the orientation words such as front, rear, upper, and lower involved are defined by the parts in the drawings and the positions between the parts in the drawings, just for the clarity and convenience of expressing the technical solution. It should be understood that the use of the location words should not limit the scope of protection claimed in this application.

In the case of no conflict, the above-mentioned embodiments and features in the embodiments herein may be combined with each other.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (10)

1. The working fluid level sensor is characterized by comprising a sealing head, a sealing seat, an outer shell and a base which are connected in sequence, the working fluid level sensor further comprises a lead, a circuit board, a bubble probe, a temperature probe and a strain gauge, the circuit board, the bubble probe and the temperature probe are all located in the outer shell, the strain gauge is located in the base, the lead, the bubble probe, the temperature probe and the strain gauge are connected with the circuit board respectively, the bubble probe is used for obtaining the average density of fluid, the strain gauge is used for measuring the pressure of the fluid, the temperature probe is used for measuring the temperature, and the temperature measured by the temperature probe is used for correcting the pressure measured by the strain gauge so as to eliminate temperature drift of the strain gauge.

2. A working fluid level sensor suitable for two-phase gas-liquid flow according to claim 1, wherein the outer casing comprises an upper end and a lower end, the sealing head is in threaded connection with the upper end of the sealing seat, the lower end of the sealing seat is in threaded connection with the upper end of the outer casing, the lower end of the outer casing is in threaded connection with the base, a first rubber ring is arranged at the joint of the sealing head and the sealing seat, a first groove for placing the first rubber ring is arranged at the upper end of the sealing seat, a sealing gasket is arranged at the joint of the upper end of the outer casing and the sealing seat, a second groove for placing the sealing gasket is arranged at the upper end of the outer casing, a rubber sealing ring is arranged at the joint of the lower end of the outer casing and the base, the lower end of the outer casing is stepped, and the rubber sealing ring is placed at the step of the lower end of the outer casing.

3. A working fluid level sensor suitable for two-phase gas-liquid flow according to claim 2, wherein one end of the wire is connected to the circuit board through the central holes of the seal head, the first rubber ring and the seal seat in sequence, the first rubber ring is compressed at the joint of the seal head and the seal seat, so that the first rubber ring is tightly attached to the wire to seal the wire, and the other end of the wire is connected to the terminal device.

4. A dynamic liquid level sensor suitable for two-phase gas-liquid flow as claimed in claim 1, wherein a clamping seat is connected to the inside of the outer shell, the clamping seat is in threaded connection with the inside of the outer shell, a first threaded blind hole is formed in the clamping seat, a first through hole is formed in the circuit board, the circuit board can be fixed on the clamping seat by inserting bolts into the first through hole and the first threaded blind hole, and an inner hexagonal groove is formed in the end face of the clamping seat to facilitate screwing and unscrewing with an inner hexagonal wrench.

5. A dynamic liquid level sensor suitable for two-phase gas-liquid flow as claimed in claim 1 wherein the outer shell is connected with a gland, the joint of the outer shell and the gland is provided with a second rubber ring, the outer shell is provided with a third groove for placing the second rubber ring, the outer shell is provided with a second threaded blind hole and a second through hole, the bubble probe sequentially passes through the gland, the central hole of the second rubber ring and the second through hole and then is connected with the circuit board, the gland is provided with a third through hole, the gland can be fixedly connected to the outer shell by inserting screws into the third through hole and the second threaded blind hole, and the gland compresses the second rubber ring to seal the bubble probe.

6. The two-phase flow liquid level sensor according to claim 5, wherein a protective cap is further attached to the outer shell, the protective cap is located above the gland, the protective cap has a fourth through hole, the protective cap is fixedly attached to the outer shell by inserting a screw into the fourth through hole and the second threaded blind hole, and the protective cap protects the bubble probe.

7. The working fluid level sensor suitable for two-phase gas-liquid flow according to claim 1, wherein a fourth groove is formed in the base, a strain gauge with a waterproof function is placed in the fourth groove, a pressing ring is arranged above the strain gauge and located at a joint of the clamping seat and the inner portion of the outer shell, and the pressing ring is used for sealing the strain gauge.

8. A working fluid level sensor suitable for two-phase gas-liquid flow according to claim 1, wherein the circuit board is provided with a third threaded blind hole, the temperature probe is screwed into the third threaded blind hole through threaded connection so as to connect the temperature probe with the circuit board, and the circuit board is connected with a data processing circuit for processing data detected by the strain gauge, the bubble probe and the temperature probe.

9. Use of a mobile liquid level sensor adapted for gas-liquid two-phase flow according to any of claims 1 to 8, characterized in that it comprises the following steps:

installing the working fluid level sensor on an oil pipe, then placing the oil pipe provided with the working fluid level sensor below the working fluid level in the well to obtain a first height, wherein the first height is the depth from the installation position of the working fluid level sensor to the well head, and meanwhile, the pressure of the air at the well head is obtained;

inputting the first elevation and a pressure of wellhead air to a terminal device;

starting a dynamic liquid level sensor, measuring by using the strain gauge to obtain fluid pressure at the installation position of the dynamic liquid level sensor, obtaining the average density of fluid between the installation position of the dynamic liquid level sensor and the dynamic liquid level by using the bubble probe, and transmitting the fluid pressure and the average density to terminal equipment;

and the terminal equipment processes the received fluid pressure and the average density to obtain the working fluid level height.

10. Use of a meniscus level sensor suitable for two-phase gas-liquid flow according to claim 9, characterized in that the meniscus level is obtained by:

calculating the pressure generated by the liquid at the mounting position of the working fluid level sensor, wherein the calculation formula of the pressure generated by the liquid at the mounting position of the working fluid level sensor is as follows:

P ₂ ＝P ₁ -P ₀

in the formula, P ₂ For the pressure of the liquid at the location of the mounting of the dynamic liquid level sensor, P ₁ For measuring the fluid pressure at the mounting position of the dynamic liquid level sensor by means of strain gauges, P ₀ The pressure of the wellhead air;

calculating a second height, wherein the second height is the depth of the working fluid level from the mounting position of the working fluid level height sensor, and the calculation formula of the second height is as follows:

h ₂ ＝P ₂ /ρg

in the formula, h ₂ At a second height, ρ is the average density obtained with the bubble probe, g is the gravity constant;

calculating the height of the working fluid level, wherein the calculation formula of the height of the working fluid level is as follows:

h ₃ ＝h ₁ -h ₂

in the formula, h ₃ Is the working fluid level, h ₁ Is a first height.

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