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→Oil-based muds
* ''Disposal''—Oil mud cuttings may have to be cleaned up before dumping. Some regulatory agencies require cuttings be sent to a designated disposal area.
* ''Disposal''—Oil mud cuttings may have to be cleaned up before dumping. Some regulatory agencies require cuttings be sent to a designated disposal area.
* ''Kick detection''—H<sub>2</sub>S, CO<sub>2</sub> and CH<sub>4</sub> are soluble in oil muds. If gas enters the wellbore, it can go into solution under pressure. As the gas moves up the wellbore, it can break out of solution at the bubble point and rapidly evacuate the hole, blowing the mud with it.
* ''Kick detection''—H<sub>2</sub>S, CO<sub>2</sub> and CH<sub>4</sub> are soluble in oil muds. If gas enters the wellbore, it can go into solution under pressure. As the gas moves up the wellbore, it can break out of solution at the bubble point and rapidly evacuate the hole, blowing the mud with it.
* ''Formation evaluation''—Some wireline logs should not be run in oil-based muds. Also, additional steps are needed to remove oil coatings from cuttings before they are described. (For more information on wireline tool compatibility with drilling fluid composition, see [[Basic tool table]], and for more on removing oil coatings from cuttings, see [[Mudlogging: Drill cuttings analysis]].)
* ''Formation evaluation''—Some wireline logs should not be run in oil-based muds. Also, additional steps are needed to remove oil coatings from cuttings before they are described. (For more information on wireline tool compatibility with drilling fluid composition, see [[Basic tool table]], and for more on removing oil coatings from cuttings, see [[Mudlogging: drill cuttings analysis]].)
Oil-based muds contain three phases: ''oil, brine,'' and ''solids phase.''
Oil-based muds contain three phases: ''oil, brine,'' and ''solids phase.''