Determination of Steam Quality and Flow Rate Using Pressure Data From an Orifice Meter and a Critical Flowmeter

A method for measurement of steam quality and flow rate has been developed, laboratory tested, and packaged for thermal EOR applications. The method consists of an orifice flow meter in series with a critical flow meter. The flow through the orifice is subcritical. The critical-flow meter can be a static choke, a venturi, a nozzle, or a thick orifice, etc. Steam flow rate equations for orifice flow and for critical flow were established with empirically derived constants. These two equations were combined and solved to determine the steam quality and flow rate. The basic mechanical parts of the measurement system are rugged and inexpensive. The pressure transmitters and flow computer are portable and can be used for spot checks or for continuous monitoring. The steam quality and flow rate information obtained make it possible to evaluate the performance of steam distribution systems and thus to identify where modifications to the distribution system piping are needed.