Correlation (ratio) – value characterizing interrelation of two random variables irrespective of whether it is defined by cause-and-effect relation or just an accidental coincidence (false correlation).

In the oil and gas industry there is a concept of strata correlation or identification of strata – tracing reservoir (strata) properties or features within a certain area as a point section (well, geological explosion). Correlation may be based on different parameters (lithology, reservoir characteristics, statistics, geochemical parameters, etc.).