Infrared absorption-based composition sensor for fluid mixtures

A system for gathering information about physical properties of a fluid mixture in a lateral section of an oil-gas producing well, the system comprising:

• a mobile vessel configured for submersion in the fluid mixture of the lateral section of the oil-gas producing well, the fluid mixture comprising water, methane and crude oil;
• and
• a composition sensor attached to the mobile vessel, the composition sensor comprising:
• a pair of opposing arms separated by a distance that defines a length of a measurement flow channel of the composition sensor through which measurement flow channel the fluid mixture can pass;
• an emission aperture and a collection aperture oppositely arranged in the pair of opposing arms and having respective oppositely arranged surfaces separated by said distance and in contact with the fluid mixture upon passing of the fluid mixture through the measurement flow channel;
• and
• a plurality of spectrally narrow emission sources having respective plurality of emission wavelength bands in an infrared wavelength region between 1400 nm to 1800 nm,
• wherein the lateral section of the oil-gas producing well comprises a plurality of perforated production zones for provision of a combined inflow of the fluid mixture,
• wherein the mobile vessel is further configured for positioning near each perforated production zone of the plurality of perforated production zones for measurement of a respective inflow contribution to the combined inflow of the fluid mixture, the respective inflow contribution based on relative concentrations of the water, methane and crude oil of the fluid mixture measured by the composition sensor near the each production zone,
• wherein the plurality of emission wavelength bands includes three emission wavelength bands that overlap absorption wavelength bands of the water, methane and crude oil of the fluid mixture, and
• wherein the composition sensor is configured to emit the plurality of emission wavelength bands through the emission aperture according to a time multiplexing scheme for measurement of the relative concentrations of the water, methane and crude oil.