Total Organic Carbon


Total Organic Carbon or TOC is a method of screening rock samples to determine their organic content.

Total organic carbon measures the amount of carbon associated with the organic matter of a given rock sample including core, sidewall core, outcrops, and cuttings samples.

Weatherford Laboratories performs an acid digestion of all samples undergoing TOC analysis.

By treating crushed rock samples prior to analysis with HCl, carbonate carbon is removed, assuring TOC values are not falsely elevated due to the presence of mineral carbon.

Weatherford Laboratories utilizes the LECO C744 for fast, accurate TOC determination.

Acid treated, crushed rock samples are combined with accelerants and burned in an oxygen-rich evironment to produce carbon dioxide which is accurately measured with an infrared detector.

General TOC guidelines for Source Rocks

  • Poor = < 0.5%

  • Fair = 0.5 to 1%

  • Good = 1 to 2%

  • Very Good = 2 to 4%

  • Excellent = > 4%

Log generated using IsologicaTM software


When TOC is performed in conjunction with programmed pyrolysis (Source Rock Analysis), a wealth of information can be gathered on the hydrocarbon generative potential of a given source rock.