Method and apparatus for analyzing composition of hydrocarbon and carbon dioxide gases liberated from drilling fluids

摘要

In various embodiments is described a device and method for rapidly analyzing compositions of gases liberated from drilling fluid using spectral absorption analysis. Specifically the invention describes flowing the sample gas thru a closed path gas cell, irradiating the sample gas with a wide band infrared emitter in the 2 to 5 μm wavelength range, measuring the infrared absorbance spectrum in the range of 2 to 5 μm using a spectrometer and determining the composition of the gas sample using multivariate analysis of the spectrum. The composition includes the concentration of any one or more, either singularly or in combination, of hydrocarbon gases containing one to eight carbon atoms and carbon dioxide gas.

主权项

1. A device that analyzes the composition of hydrocarbon gases comprising methane, ethane, propane, n-butane, iso-butane, n-pentane, iso-pentane, neo-pentane, hexane isomers, heptane isomers, and octane isomers released from drilling muds, wherein the device comprises a wide band infrared emitter, a gas cell in which the sample gas is irradiated, a Fourier Transform Infrared (FTIR) spectrometer measuring a primary hydrocarbon absorption spectrum of 3.15 to 3.55 μm and primary absorption spectrum shoulder regions of 2.9 to 3.15 μm and 3.5 to 4.2 μm, a focusing optic element that directs gas cell radiation into the spectrometer, and a system processor that performs analysis of the absorption spectrum to determine the gas composition.