Downhole sample analysis method

摘要

A method for downhole fluid analysis is disclosed. The method includes positioning a downhole fluid sampling tool at first and second locations; extracting and compositionally analyzing samples of reservoir fluid while positioned at the first and second locations; comparing analysis results; and repositioning the tool to a third location depending on the results of the comparison. The compositional analysis can be performed using downhole gas chromatography and mass spectrometry systems and preferably can identify subtle non-homogeneities such as biomarkers. The fluid extraction can be performed using a focuses dual-flowline type sampling probe.

主权项

1. A method for surveying a formation, the method comprising:
positioning a tool at a first location in a borehole, the tool including a downhole fluid analysis system; extracting a first sample of reservoir fluid while the tool is positioned at the first location; performing a compositional analysis of the first sample using the downhole fluid analysis system, wherein the compositional analysis includes identifying individual molecules having at least 10 carbon atoms; repositioning the tool to a second location in the borehole, wherein the second location is different from the first location; extracting a second sample of reservoir fluid while the tool is positioned at the second location; performing a compositional analysis of the second sample using the downhole fluid analysis system, wherein the compositional analysis includes identifying individual molecules having at least 10 carbon atoms; comparing compositional analysis results of the first sample and the second sample using individual molecules having at least 10 carbon atoms; repositioning the tool back to a third location that is within the borehole between the first location and the second location, wherein the repositioning depends at least in part on the comparison of the first sample and the second sample; extracting a third sample of reservoir fluid while the tool is positioned at the third location; and performing a compositional analysis of the third sample using the downhole fluid analysis system, wherein the compositional analysis includes identifying individual molecules having at least 10 carbon atoms.