Background
As most oil wells in oil fields in China are in the later development stage, the liquid production amount is low, the water content rises quickly, meanwhile, the international oil price is greatly reduced under the influence of the world economic environment, more and more pressure is caused on the low-cost operation of the oil fields in China, and the problems of liquid production amount measurement of the oil wells and real-time detection of the water content of the oil wells are also vital parameters for oil well production.
The chinese application patent ZL2005101032890 discloses a dynamometer method oil well metering device, as shown in fig. 1, comprising a well site power supply, a load sensor 3, a displacement sensor 1, a remote data control terminal RTU module installed in an oil well RTU cabinet 2, and a data transmission receiving device; the load sensor 3 is arranged on a wellhead rope hanger, and the displacement sensor 1 is arranged at the position of the walking beam of the oil pumping unit corresponding to the bracket.
The working principle is that the load sensor 3 and the displacement sensor 1 are adopted to respectively detect the load and the displacement of the sucker rod at the wellhead of the oil well, a finite element model and a liquid column differential calculation model of the sucker rod and an oil pipe are respectively established according to the change rule of the load and the displacement of the sucker rod column and time, then the relation between the load and the displacement of the wellhead of the oil well and the time is iteratively solved, and the effective stroke of the oil well pump under the oil well is obtained through the processing of a computer. The product of the effective stroke of the oil well pump and the volume of the annular space of the piston of the oil well pump is the instantaneous liquid production amount of the wellhead of the oil well, and the instantaneous liquid production amount is stored in a database.
If the measured data group point is larger than 200 groups in one stroke cycle (about 15 seconds) of the sucker rod, within the calculation time of 5-10 minutes, due to the limitation of the data transmission technology and production metering software on the operating system, only one stroke cycle measured data group can be used for replacing the measured data group in the rest time periods, and therefore certain errors can occur in the measurement of the liquid production amount of the oil well.
When the oil well is a slug flow oil well, the oil pumping unit can generate gas in the oil outlet pipeline of the wellhead for a period of time in the oil pumping process, so that the problem of inaccurate measurement of the liquid yield of the oil well can also occur.
Disclosure of Invention
In order to solve the problems, the invention provides an oil well metering method based on combination of water content detection and a power diagram method, which comprises the following steps: the method comprises the following steps of adopting a displacement sensor, a load sensor, a water content analyzer and an intelligent analysis unit, wherein the displacement sensor detects sucker rod displacement data changing along with time in real time, the load sensor detects sucker rod load data changing along with time in real time, the water content analyzer detects liquid water content data changing along with time in a wellhead oil outlet pipeline in real time, and the intelligent analysis unit is installed in an oil well platform RTU cabinet; firstly, an intelligent analysis unit calculates the initial liquid production amount of an oil well in unit time by using a power diagram method through detecting the displacement of the sucker rod and the time-varying load data; if the water content of the effluent of at least one pumping unit stroke in unit time is zero, the intelligent analysis unit eliminates the corresponding oil production capacity with the water content of zero in the pumping unit stroke from the initial oil production capacity, and finally the intelligent analysis unit outputs the final oil production capacity of the oil well in unit time; if the water content of the stroke effluent of the pumping unit is not zero in unit time, the intelligent analysis unit directly outputs the initial liquid production amount of the oil well in unit time.
The displacement sensor is an acceleration or angle displacement sensor.
The load sensor is arranged on the wellhead rope hanger.
The water content analyzer is arranged on the oil outlet pipeline of the wellhead.
The moisture content analyzer is a microwave moisture content analyzer.
The output of the intelligent analysis unit further comprises the step of sending the water content data in unit time to an oil field monitoring center.
The output of the intelligent analysis unit also comprises the step of sending the historical data of the oil well indicator diagram and the historical data of the water content to an oil field monitoring center.
The aforesaid set up a blow-down valve on the oil outlet pipe way, when the moisture content judgement is unusual, the output of intelligent analysis unit still includes and opens signal transmission to oil field monitoring center with the blow-down valve.
According to the invention, by combining the water content detection and indicator diagram method, indicator diagram data are collected in real time to calculate each indicator diagram, the liquid production amount in any time is obtained through accumulation, whether the liquid outlet of the well mouth is continuously judged by using a water content analyzer, and once the intermittent condition of the liquid outlet of the well mouth occurs, the indicator diagram corresponding to the liquid lack at the well mouth is removed by an intelligent analysis unit, so that the accuracy of the measurement of the liquid production amount of the oil well is greatly improved.
Detailed Description
The concept, specific structure and technical effects of the invention will be further described below by taking an oil well metering method based on the combination of microwave water content detection and a power diagram method as an example and combining the drawings thereof, so as to fully understand the purpose, characteristics and effects of the invention.
As shown in fig. 2, the oil well metering device based on the combination of microwave moisture detection and a power diagram method mainly comprises a displacement sensor 1, a load sensor 3, a microwave moisture content analyzer 8, an intelligent analysis unit (installed in an oil well RTU cabinet 2'), a casing valve 4, a production valve 5, an emptying valve 6 and a back pressure valve 7; wherein:
A. the load sensor 3 is arranged on a wellhead rope hanger, the measuring range of the load sensor 3 is 0-150 kN, the precision is 0.5%, and when the pumping unit works, the load sensor 3 is under the pressure of the suspension point load of the sucker rod, and a load and time change curve is obtained;
B. the displacement sensor 1 is arranged at the position, corresponding to the support, of the beam of the pumping unit, the measuring range of the displacement sensor 1 is 0-5 m, the precision is 0.5%, the displacement sensor is used for measuring the swing angle of the beam pumping unit, converting the swing angle into a 4-20 mA output signal, and converting the motion displacement and time change curve of the pumping rod through an angle change value;
C. the microwave water content analyzer 8 is arranged on an oil outlet pipeline behind the production valve 5 and is used for detecting the water content of liquid in the oil outlet pipeline at the well mouth and a time change curve, and the data acquisition frequency is not lower than 200 ms;
D. the intelligent analysis unit is arranged in the RTU cabinet 2 ', the RTU cabinet 2' is arranged on a wellhead platform, and a CPU (central processing unit) of the intelligent analysis unit selects more than or equal to two core dominant frequencies 1GHZ of Cortex-A9; the intelligent analysis unit directly calculates and analyzes load and displacement data acquired on site, outputs indicator diagram production and oil well working condition diagnosis information, does not need to upload the data to a server of a monitoring center and calculate through calculation and diagnosis software of the server, so that the abnormal oil well can be found immediately and processed if the abnormal oil well occurs, the indicator diagram of each stroke of the pumping unit is calculated and analyzed, and the timeliness of oil well calculation and analysis is greatly improved; if the pumping unit strokes are carried out for 4 times per minute, 5760 actual oil extraction indicator diagrams are obtained every day, so that the timeliness is greatly improved, and active reporting and timed uploading can be carried out through abnormal indicator diagrams. Meanwhile, the intelligent analysis unit receives the detection data of the water content of the liquid of the microwave detector and analyzes the change of the detection data, so that the conditions of the flow state in the pipe and the fullness of the liquid in the pipe can be judged.
The working principle is as follows:
1) under the working condition of continuous liquid output of the oil well:
as shown in fig. 2 and 4, a moisture content change curve is collected and analyzed by an intelligent analysis unit in an RTU cabinet 2' through a microwave moisture analyzer 8 and regularly and periodically changes along with the stroke of the pumping unit, and a moisture content change curve of an oil well along with time is shown in fig. 4; the oil well liquid production measurement is that an intelligent analysis unit in an RTU cabinet 2' calculates and outputs the initial liquid production amount in unit time by a power diagram method; the initial fluid production per unit time (e.g., one hour, 12 hours, 24 hours, one week, one month, one year, etc.) is: q1+ Q2+ Q3+ Q4+ … + QN, work diagram per stroke (liquid production amount): q1, Q2, … QN. Because the water content of the stroke effluent of the pumping unit is not zero in unit time, the intelligent analysis unit directly outputs the initial liquid production amount.
2) Under the working condition of intermittent liquid discharge of an oil well:
referring to fig. 2, 3 and 5, the intelligent analysis unit in the RTU cabinet 2' monitors that the water content change curve is intermittent through the microwave water content analyzer 8, and when the water content is zero, the change curve of the water content of the oil well is shown in fig. 5 mainly because the inside of the pipe is in a gas state and almost has no liquid. The work diagram corresponding to the stroke in the full gas stroke is found out through the judgment of the intelligent analysis unit, the work diagrams of the strokes are subtracted from the accumulated work diagram, and the accumulated work diagram is carried out in the liquid stroke. The final fluid production per unit time was: Q-Q2 + Q4, Q1 and Q3 each represent the amount of fluid produced in the no-liquid stroke, and Q2 and Q4 each represent the amount of fluid produced in the liquid stroke.
Therefore, the diagram method measurement and the microwave water content analyzer are combined to measure the liquid production quantity in real time, the liquid production quantity value in any unit time can be taken, and the error of the slug flow full gas stroke diagram is eliminated; if the work diagram of each stroke is continuously analyzed, calculated and accumulated to obtain the oil yield of the oil well in different unit time periods, the problems of unstable liquid output and large oil well liquid yield measurement error caused by gas influence are solved, and the oil quantity and the water quantity in the oil well liquid yield are accurately mastered.
The oil well metering method based on the combination of the microwave moisture detection and the indicator diagram method, as shown in figures 2 and 7, also has the state detection (namely the anti-theft function) of the emptying valve 6: the change curve of the water content is collected and analyzed through an intelligent analysis unit and changes regularly and periodically along with the stroke of the pumping unit; when the emptying valve 6 is opened, the moisture content curve tends to be in a stable liquid state, and the change process along with the up-down stroke rule of the pumping unit does not exist, as shown in figure 7; the state detection of the emptying valve 6 can also adopt an oil outlet pipeline to set a pressure transmitter to detect the reduction of the pressure, and the condition that the emptying valve 6 is opened at the moment can be judged, and the liquid in the pipeline flows out at the emptying valve 6; the state detection of the emptying valve 6 can also adopt an oil outlet pipeline to arrange a pressure transmitter and a microwave water content analyzer.
In the above embodiments, the displacement sensor may also be an acceleration angular displacement sensor.
In the above embodiments, the microwave moisture content analyzer may also be another moisture content analyzer based on a microwave principle.
In order to accurately count the water content in the oil well liquid production amount, the output of the intelligent analysis unit further comprises the step of sending the water content data in unit time to an oil field monitoring center.
In order to inquire and know the actual oil well liquid production capacity and the water content condition in the liquid production capacity, the output of the intelligent analysis unit further comprises the step of sending the indicator diagram historical data and the water content historical data of the oil well to an oil field monitoring center.
The present application has been described in connection with only the presently preferred embodiments with the understanding that the present disclosure is not to be considered as limiting, and the present application is not limited to the examples described above, but rather, it is to be understood that changes, modifications, additions or substitutions that are within the spirit and scope of the application by one of ordinary skill in the art are included.