Continuous mud gas loggings during drilling as well as offline mud gas sampling are standard techniques in oil and gas exploration, where they are used to test reservoir rocks for hydrocarbons while drilling.

ICDP’s Online Gasmonitoring OLGA extends this technique for scientific drilling in hydrocarbon and non-hydrocarbon formations to sample and study the composition of crustal gases [1]. Online-Gasmonitoring of drilling mud is a three-step process, comprising: