Online Gas Analysis

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.

Online Gas Monitoring at SAFOD


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:


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Gas release from the formation

Drilling mud gas that circulates in the borehole comprises air and gaseous components that are mechanically released as the drill bit, including components present in the pore space of the crushed rock and gas entering the borehole through permeable strata; either as free gas or, more likely, dissolved in liquids. Continuous inflow of fluids in the borehole along the entire borehole wall is hampered through the rapid formation of mud-cake that covers the borehole wall and acts as a seal.