초록 ▼

A borehole tool analyzes the composition of gases flowing from a formation. The tool includes an optical fluid analyzer (OFA) and a gas analysis module (GAM). The OFA determines when fluid flowing into the tool has become substantially only gas. The gas is then diverted to the GAM, thereby avoiding

A borehole tool analyzes the composition of gases flowing from a formation. The tool includes an optical fluid analyzer (OFA) and a gas analysis module (GAM). The OFA determines when fluid flowing into the tool has become substantially only gas. The gas is then diverted to the GAM, thereby avoiding the possibility of oil depositing itself on a optical window and interfering with a proper analysis. The GAM includes a near infrared ray light source, at least one photo-detector, a gas sample cell (or cells) having portions with different path lengths, each portion having an optical window, and fiber optics which direct light in first paths from the source to the sample cell, and from the sample cell to the photo-detectors. By providing cells with different path lengths, issues of dynamic range are obviated. The GAM also preferably includes a second optical path which goes directly from the light source to the photo-detectors and is used for canceling drift, and a third optical path which goes from the light source, through a known standard such as methane to the photo-detectors and is used for compensation of shifts in actual hydrocarbon peak locations or shifts in optical filter wavelengths. Analysis of the different hydrocarbon gas components of the gas stream is conducted by analysis of selected CH vibrational peaks in the 5700 cm.sup.-1 to 6100 cm.sup.-1 range.

대표청구항 ▼

[ What is claimed is:] [1.] A borehole tool for investigating gases from a formation traversed by a borehole, comprising:a) means for obtaining a stream of fluid from the formation, said stream of fluid comprising at any one time, at least one of gas, oil, water, and borehole mud;b) means for determ

[ What is claimed is:] [1.] A borehole tool for investigating gases from a formation traversed by a borehole, comprising:a) means for obtaining a stream of fluid from the formation, said stream of fluid comprising at any one time, at least one of gas, oil, water, and borehole mud;b) means for determining when said stream of fluid is comprised of substantially all gas;c) diverter means coupled to said means for obtaining and to said means for determining, said diverter means for diverting formation gas into a second stream separate from said stream of fluid when or after said means for determining determines that said fluid is comprised of substantially all gas; andd) means for determining indications of the composition of said formation gas in said second stream.