Patent ID: 8011238

Claim:
A method for characterizing formation fluid present in a subsurface earth formation, the method comprising: extracting a plurality of gas components from a volume of drilling mud comprising formation fluid and gases, while drilling; measuring a gas trap value for each gas component of interest; determining a gas trap response factor for each gas component of interest by dividing the gas trap value by a laboratory fluid analysis value for each gas component of interest; determining a relative response factor for each gas component of interest by dividing the gas trap response factor for each gas component of interest by the gas trap response factor for the gas component of interest with the lowest molecular weight; and calculating the corrected gas trap value for each gas component of interest by dividing the gas trap value by the relative response factor for each gas component of interest; wherein the corrected gas trap value for each gas component of interest is utilized to calculate gas/oil ratios for characterizing the formation fluid from the volume of drilling mud.