Optimization Research On Flow Parameters Acquisition Of Virtual Metering System

Compared with the conventional entity multiphase flow meter, virtual metering system has obvious advantages in gas-liquid multiphase flow metering. The cost of investment is low, flow measurement precision is high, powerful, system maintenance convenience and so on. In order to improve the measurement accuracy, this paper has done some research on analyzing the flowing parameters of virtual metering system, describing the choke valve’s fluid flowing control equation, introducing the gas-liquid flow in the vertical well bore, discussing the characteristic parameters, flow pattern discrimination and its influencing parameters. Pressure gradient calculation is analyzed after listing the formulas of acceleration pressure gradient, weight-level gradient and friction gradient. And the temperature distribution is also researched, especially the convective heat transfer coefficient calculation of gas-liquid flow in the well bore. By analyzing the density, velocity and the volume fraction of gas-oil-water, we get an approximate formula for the flow rate of total phases and each phase of gas-oil-water, considering the parameters including formation volume coefficient, gas oil rate,and the oil water rate. Taking the Yacheng 13-4 gas-field A1 well for example, the nominal diameter and basic flow parameters of choke valve are calculated, the distribution of fluid field of different openings, flow rate and water cut, and the pressure field and temperature filed of pressure gauge carrier is simulated,providing reference ideas for the virtual metering system’s data collection.