Gas and liquid metering method and system for plunger gas lifting device for well

The invention belongs to the technical field of natural gas equipment, and relates to a gas and liquid metering method and system for a plunger gas lifting device for a well. A plunger lifts a liquidcolumn to rise slowly under the pressure of oil jacket pressure; the oil pressure is collected by a plunger reaching sensor; whether the liquid column reaches or not is judged through calculation; when the liquid column reaches, the plunger reaching sensor sends a liquid metering instruction to an ACF two-phase flow flowmeter to start accumulated liquid metering; and after the liquid column is drained, i.e., the plunger reaches the top, the plunger reaching sensor detects reaching of the plunger, then, a gas metering instruction is sent to the ACF two-phase flow flowmeter to recover accumulated gas metering. The gas and liquid metering method has the characteristics that the effective metering on the gas and liquid quantity of a gas production single well is realized by using a method of judging the reaching of a