Exploration & Production
High Void Fraction Multiphase Meter
Significant progress has been made recently in the metering of multiphase fluids by homogenizing the flow in a mixer, then metering the pseudo-single phase fluid in a venturi in concert with a gamma densitometer or similar device. While the upper limit of applicability of this approach is ill defined, it is generally thought that for void fractions greater than about 90-95%, a homogeneous mixture is difficult to create or sustain.
Working together, the INL and Perry Equipment Company (PECO) have shown that by measuring the pressure response at several locations (in a venturi or extended throat nozzle), a unique relationship between measured pressure differentials and the mass flow rates of each phase allows measurements of each phase to be calculated.
Average of gas mass flow rates to within a fraction of a percent and liquid mass flow rates to within a few percent are now possible in flow streams that consist of 90% or greater void fraction (gas volume). We expect this meter to be an important tool for reservoir management of wet gas wells. PECO installed beta units on several wells in central Texas. Additional testing is now being performed by FMC-Smith metering.