A mudlogger in the modern oil field is primarily tasked with gathering data and collecting samples during the drilling of a well and organizing this information in the form of a graphic log, showing the data charted on a graphic representation of the wellbore. Mudloggers observe and interpret the indicators in the mud returns during the drilling process. The mudlogger logs at regular intervals, properties such as drilling rate, mud weight, flowline temperature, natural gas content and type, oil indicators, pump pressure, pump rate, lithology (rock type) of the drill cuttings, and various other items of interest. The job of a mudlogger requires a good deal of diligence and attention. Sampling the drill cuttings must be performed at proper intervals, for example, and can be difficult during rapid drilling. Another important task of the mudlogger is to monitor gas levels and notify other personnel on the rig when gas levels may be reaching dangerous levels. High gas levels create a fire/explosion hazard and may require the suspension of nearby work, such as welding. High gas levels may also indicate circumstances downhole that need to be addressed to avoid a dangerous well blowout.

Resource extraction occupations | Petroleum production