Radio frequency based void fraction determination

Abstract

Methods, apparatuses, and embodiments related to estimating void fractions in real-time or substantially real-time without disrupting a production flow of, e.g., a geothermal power plant. Some embodiments describe methods and systems of determining void fraction of a two-phase mixture extracted from a geothermal well by measuring the attenuations of one or more radiofrequency signals in a fixed span of a transportation unit (e.g., a pipe). Depending on void fraction of the two-phase mixture in the transportation, the RF signals would attenuate differently across the fixed span. For example, a monitor system can utilize one or more transmitter antennas in the transportation unit to transmit one or more RF signals and utilize one or more receiver antennas to measure attenuations of these RF signals over the fixed span. In some embodiments, an antenna can be configured to serve as both a transmitter antenna and a receiver antenna.

What is claimed is: 
     
         1 . A method of computing void fraction in a two-phase mixture extracted at a geothermal power plant, comprising
 transmitting a radio frequency (RF) signal through a transportation pipe during production operation of a geothermal well, the transportation pipe conveying the two-phase mixture extracted from the geothermal well, wherein the RF signal passes through the two-phase mixture;   measuring signal strength attenuation of the RF signal received at a receiver antenna in the transportation pipe;   computing a void fraction of the two-phase mixture based on the signal strength attenuation;   computing enthalpy in the two-phase mixture based on the void fraction; and   dynamically adjusting a steam field of the geothermal power plant based on the computed enthalpy.   
     
     
         2 . A void fraction measurement device comprising
 a driver circuit configured to generate an RF signal;   a first antenna attached inside a pipe to transmit the RF signal through the pipe while the pipe is transporting a two-phase mixture;   a second antenna attached inside a pipe to receive the RF signal;   a receiver circuit configured to measure an attenuation reading associated with the RF signal after traversing through the two-phase mixture; and   a transceiver to wireless transmit the attenuation reading or a void fraction estimation calculated based on the attenuation reading to a computing device outside of the pipe.