Mud logging of natural hydrogen

A system for estimating a natural quantity of natural hydrogen in a subterranean formation, the system comprising:

• a degasser disposed to degas drilling fluid at a rig site to obtain a gas sample;
• a calibrated mass spectrometer configured to measure a sample concentration of hydrogen gas and a sample quantity of a second gas in the gas sample, wherein the calibrated mass spectrometer is calibrated for making calibrated hydrogen measurements based on a correlation between a measured hydrogen concentration and an actual hydrogen concentration;
• and
• a processor configured to evaluate the sample concentration of hydrogen gas and the sample quantity of the second gas and apply a correction to the measured concentration of hydrogen to estimate the natural quantity of the natural hydrogen in the subterranean formation.

A method comprising:

• calibrating a mass spectrometer for making hydrogen measurements to obtain a calibrated mass spectrometer including a correlation between a measured hydrogen concentration and an actual hydrogen concentration;
• obtaining a drilling fluid gas sample from a subterranean formation, the drilling fluid gas sample including a quantity of hydrogen gas;
• evaluating the drilling fluid gas sample to measure, using the calibrated mass spectrometer, a sample concentration of hydrogen gas and to measure a sample quantity of a second gas in the drilling fluid gas sample;
• correlating the sample quantity of the second gas with a quantity of drill bit metamorphism (DBM) hydrogen in the drilling fluid gas sample;
• and
• applying a correction to the sample concentration of the hydrogen gas by subtracting the quantity of DBM hydrogen from the sample concentration of hydrogen gas to compute a natural quantity of natural hydrogen in the subterranean formation.