When the liquid in the secondtemporary storage device 10 rises to the height of the communicating pipe 11, the liquid enters the first temporary storage device 9 through the communicating pipe 11, the firstdifferential pressure transmitter 7 on the first temporary storage device 9 senses the differential pressure due to the entering of crude oil and immediately sends an instruction that the liquid in the secondtemporary storage device 10 is full to the PLCintelligent control system 15, the PLCintelligent control system 15 sends information to thecomputer 16 after receiving the feedback, and thecomputer 16 records the differential pressure value P of the seconddifferential pressure transmitter 8₂The mass m of the primary liquid phase measured by the secondtemporary storage 10 can be calculated by the above formula₂。

And obtaining a liquid phase daily yield calculation data model through the following data models:

Q_M-liquid daily yield, unit: ton/day;

m_n-weight of each measurement, unit: kilogram;

t- -measurement time, unit: second;

pump efficiency analysis procedure:

when the measurement is started, the PLCintelligent control system 15 combines the corresponding record of the size of the measured liquid amount and the measurement time relationship when the data is collected in the working process of the polished rod of the oil pumping unit from the lower suspension point to the upper suspension point, and analyzes the extraction rate of the oil pumping unit and the condition of the produced liquid overflow.

Procedure for metering the gas phase:

the gas discharged from the first temporary storage device 9 and the secondtemporary storage device 10 enters the gas pipe 13 and enters theliquid discharge pipe 2 through thegas flow meter 14, when the gas flow of the day needs to be measured, the gas flow of the starting node and the ending node of the time period needing to be measured only needs to be read from thegas flow meter 14, and the difference between the two data is the gas flow needing to be measured. A daily gas production data model is measured:

Q_v-gas daily yield, unit: nm³/d；

q_v-real-time cumulative amount of gas meter in the metering process, in units: nm³；

q'_v-cumulative amount of gas meter at the beginning of metering, in: nm³；

t- -measurement time, unit: second;

the process of measuring the water content of the crude oil comprises the following steps:

the crude oil entering the first temporary storage device 9 contains pure oil and pure water, the differential pressure value of the firstdifferential pressure transmitter 7 is adjusted to be 0 at the moment that the liquid inlet three-way valve 12 is opened, when the liquid level in the first temporary storage device 9 is at the known height H, namely the length between the connecting pipe of the differential pressure transmitter and the bottom of the inner wall of the communicating pipe, the differential pressure value of the differential pressure transmitter A is P, and the density rho of the pure oil at the corresponding temperature is found out according to the temperature of the crude oil in the pipeline at that time₀Substituting the mathematical model into the established mathematical model calculation formula to obtain the corresponding water content D of the crude oil_M. Because the crude oil contains a small amount of impurities such as minerals inWhen the water content of the crude oil is calculated, the actual condition of the crude oil on site must be considered, and a correction coefficient is adopted to correct the calculation result.

Lambda-correction factor

D_MMass water content

ρ₀Density of pure oil

ρ_wDensity of pure oil

H-liquid level height, i.e. the length of the connecting pipe of the differential pressure transmitter from the bottom of the inner wall of the communicating pipe

P-liquid differential pressure value

G-gravitational acceleration.

The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.

Claims

1. An oil well metering system, comprising: the liquid inlet pipe, the liquid discharge pipe, the liquid inlet three-way valve, the first temporary storage, the second temporary storage, the liquid outlet three-way valve, the gas conveying pipe and the communicating pipe;

only one outlet of the liquid inlet three-way valve is in an open state at any time;

a first electromagnetic valve is arranged at a first inlet of the liquid outlet three-way valve and is used for controlling the opening and closing of the first inlet of the liquid outlet three-way valve; a second electromagnetic valve is arranged at a second inlet of the liquid outlet three-way valve and is used for controlling the opening and closing of the second inlet of the liquid outlet three-way valve;

a gas flowmeter is arranged on the gas transmission pipe; the gas flowmeter is used for detecting the gas flow in the gas transmission pipe;

gas exhausted from the first temporary storage and the second temporary storage enters the gas conveying pipe and enters the liquid discharge pipe through the gas flow meter, when the daily gas amount needs to be measured, the gas amount of a starting node and the gas amount of an ending node of a time period needing to be measured are read from the gas flow meter, and the difference between the gas amount of the starting node and the gas amount of the ending node is the daily gas amount;

a gas phase one-way valve is arranged on the gas conveying pipe and is positioned at the downstream of the gas flowmeter; the gas-phase one-way valve is used for preventing gas in the gas transmission pipe from flowing backwards;

a liquid phase one-way valve is arranged on the liquid discharge pipe and is positioned at the upstream of the communication part of the liquid discharge pipe and the gas conveying pipe; the liquid-phase check valve is used for preventing the gas in the gas transmission pipe from flowing backwards into the first temporary storage and the second temporary storage;

a first differential pressure transmitter is arranged at the bottom of the first temporary storage, and a second differential pressure transmitter is arranged at the bottom of the second temporary storage; the first differential pressure transmitter is used for detecting the liquid level or the quality of the liquid in the first temporary storage; the second differential pressure transmitter is used for detecting the liquid level or the quality of the liquid in the second temporary storage;

the oil well metering system also comprises a PLC intelligent control system; the signal input end of the PLC intelligent control system is connected with the first differential pressure transmitter, the second differential pressure transmitter and the gas flowmeter, and the control output end of the PLC intelligent control system is connected with the first electromagnetic valve, the second electromagnetic valve and the liquid inlet three-way valve; the PLC intelligent control system is used for controlling the opening and closing of the first electromagnetic valve and the second electromagnetic valve and the opening and closing of the first outlet and the second outlet of the liquid inlet three-way valve according to signals of the first differential pressure transmitter and the second differential pressure transmitter; the flow rate value of the gas flowmeter is acquired;

when the liquid in the first temporary storage device rises to the height of the communicating pipe, the liquid enters the second temporary storage device through the communicating pipe, at the moment, the second differential pressure transmitter senses the pressure difference and immediately sends a 'liquid in the first temporary storage device is full' instruction to a PLC intelligent control system, the PLC intelligent control system controls the liquid inlet three-way valve to switch the flow direction of the liquid, so that the crude oil enters the second temporary storage device, the first electromagnetic valve on the liquid outlet three-way valve is opened, the liquid in the first temporary storage device enters the liquid discharge pipe through the liquid outlet three-way valve, the liquid in the first temporary storage device is discharged completely, and when the first differential pressure transmitter on the first temporary storage device senses no pressure difference signal, the first electromagnetic valve is closed; when the liquid in the second temporary storage device rises to the height of the communicating pipe, the liquid enters the first temporary storage device through the communicating pipe, at the moment, the first differential pressure transmitter senses the differential pressure and immediately sends a command of 'full liquid in the second temporary storage device' to the PLC intelligent control system, the PLC intelligent control system controls the liquid inlet three-way valve to switch the flow direction of the liquid so that crude oil enters the first temporary storage device, the second electromagnetic valve on the liquid outlet three-way valve is opened, the liquid in the second temporary storage device enters the liquid discharge pipe through the liquid outlet three-way valve, and after the liquid in the second temporary storage device is discharged, when the second differential pressure transmitter on the second temporary storage senses no differential pressure signal, the second electromagnetic valve is closed, the alternating metering of the crude oil by the first temporary storage device and the second temporary storage device is realized through the process.

2. An oil well metering system as claimed in claim 1, wherein said inlet three-way valve and said outlet three-way valve are electrically operated three-way valves.

3. A well gauging system according to claim 1, further comprising a computer; the signal input end of the computer is connected with the signal output end of the PLC intelligent control system, and the PLC intelligent control system is used for sending the detected signal to the computer; the computer is used for measuring the oil outlet data.

4. A well gauging method, applied to a well gauging system according to any one of claims 1 or 3; the oil well metering method comprises the following steps:

5. A well metering method as claimed in claim 4, further comprising: acquiring a gas flow value detected by the gas flowmeter in real time and sending the gas flow value to a computer;

after determining that the oil in the second temporary storage chamber has risen to the position of the communicating pipe, before opening the second electromagnetic valve to discharge the oil in the second temporary storage chamber through the drain pipe, the method further comprises the following steps: and acquiring a differential pressure signal detected by the second differential pressure transmitter and sending the differential pressure signal to a computer.