Dual-beam multiphase fluid analysis systems and methods

A method comprising:

• receiving a multiphase fluid within a bore of a conduit;
• passing electromagnetic radiation with multiple energy levels through the multiphase fluid within the bore of the conduit, wherein the multiphase fluid flows through the bore in an annular or annular-mist flow regime in which heavier fluid of the multiphase fluid forms a liquid film along an interior wall of the conduit defining the bore, and passing electromagnetic radiation with multiple energy levels through the multiphase fluid within the bore of the conduit includes:
• transmitting a first beam of electromagnetic radiation through the multiphase fluid along a first beam path through the bore;
• and
• transmitting a second beam of electromagnetic radiation through the multiphase fluid along a second beam path within the bore that is different from the first beam path, wherein the first beam has a length within the bore along the first beam path greater than a length of the second beam within the bore along the second beam path;
• detecting the first beam of electromagnetic radiation transmitted through the multiphase fluid at a first detector;
• detecting the second beam of electromagnetic radiation transmitted through the multiphase fluid at a second detector;
• and
• determining a radius of a gas core of the multiphase fluid within the bore.

An apparatus comprising:

• a fluid conduit including a bore;
• and
• a measurement system positioned to emit multiple beams of electromagnetic radiation through a multiphase fluid received in the bore, the measurement system including:
• at least one radiation source;
• a first radiation detector positioned to receive a first beam, of the multiple beams, emitted through the multiphase fluid along a first beam path from the at least one radiation source to the first radiation detector;
• a second radiation detector positioned to receive a second beam, of the multiple beams, emitted through the multiphase fluid along a second beam path from the at least one radiation source to the second radiation detector, wherein the first beam has a length within the bore along the first beam path greater than a length of the second beam within the bore along the second beam path;
• and
• a computer encoded with instructions to calculate a gas fraction of the multiphase fluid based on the first beam received by the first radiation detector and to calculate a water-in-liquid ratio of the multiphase fluid based on the second beam received by the second radiation detector.