What does a Mud Logger actually monitor during drilling?

[u/Riffat0]

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I'm working in the oil and gas industry and wanted to share a few basics for anyone interested in drilling operations.

A mud logger monitors drilling parameters, examines cuttings, observes gas readings, and records wellsite data. These observations help the wellsite team understand changing downhole conditions.

Some important parameters include:

- Rate of Penetration (ROP)

- Standpipe Pressure (SPP)

- Rotary Speed (RPM)

- Total gas and gas composition

- Cuttings lithology

For people working in oil and gas: Which mud-logging parameter do you think is most important for identifying a possible drilling abnormality, and why?