InSitu Composition

Reservoir fluid composition sensor

Representation of fluid sampling at the reservoir

The foundation of downhole fluid analysis: Optical absorption spectroscopy

The InSitu Composition reservoir fluid composition sensor of the InSitu Fluid Analyzer system employs dual spectrometers to analyze hydrocarbons, gas/oil ratio (GOR), CO2, water content, and mud filtrate contamination across the spectrum of visible through near-infrared light. The analysis is refined with an algorithm developed from the Beer–Lambert law, which indicates that the optical absorption of a component is proportional to its concentration. Thus, the spectrum of a live oil is a weighted sum of the absorptions of its individual components.

InSitu composition sensor
InSitu Fluid Analyzer system integrates multiple InSitu Family downhole quantitative fluid properties measurements and sensors.
InSitu Composition sensor graph
This graph demonstrates excellent agreement between InSitu Fluid Analyzer system and laboratory composition measurement data.
InSitu Composition sensor graph

Real-time downhole measurements confirmed in the laboratory

The accuracy of fluid composition measurements from the InSitu Composition sensor is demonstrated by their excellent agreement with laboratory data.

Both the heavy and light ends are accounted for in the downhole measurement. The algorithm used by the InSitu Composition sensor characterizes the C6+ group on the basis of wax and branched-alkane content with a correction for spectrum variation. For the first time with a downhole spectrometer, ethane (C2) is independently determined through increased resolution and advanced deconvolution. This extra capability in analyzing light-end hydrocarbon components is critical for productivity analysis and economic assessment.