Patent ID: 7095012

Claim:
A method of providing a chemical compositional analysis while sampling a formation fluid in an oilfield environment comprising: extracting a formation fluid sample; transmitting near-infrared light through the formation fluid sample; detecting indications of near-infrared absorptions from the formation fluid sample; analyzing the indications of near-infrared light absorptions using a principal component regression model, wherein the principal component regression model is established before sampling the formation fluid in the oilfield environment and establishing the principal component regression model comprises: constructing a calibration data matrix from a plurality of near-infrared absorption spectra of calibration samples; determining the principal components of the calibration data matrix; decomposing the calibration data matrix into a matrix of the principal components and a matrix of scores for the plurality of calibration spectra; and determining a plurality of regression vectors, each of which relates concentration of a constituent compound in the calibration samples to the matrix of scores; and determining concentrations of a plurality of compounds in the formation fluid sample, the plurality of compounds including: methane and carbon dioxide.