Any group of oils will inevitably exhibit variations among the members. This “natural variation” can stem from true differences, sample handling, analytical error, or differences in technique between laboratories. The amount of acceptable or “normal” difference varies greatly, depending on the range of maturities, [[biodegradation]], expulsion and [[migration]] (the effects of which are especially large when comparing oils with source rock extracts), and variations in source rock facies. Correlations become increasingly difficult and tenuous as distances between samples increase. | Any group of oils will inevitably exhibit variations among the members. This “natural variation” can stem from true differences, sample handling, analytical error, or differences in technique between laboratories. The amount of acceptable or “normal” difference varies greatly, depending on the range of maturities, [[biodegradation]], expulsion and [[migration]] (the effects of which are especially large when comparing oils with source rock extracts), and variations in source rock facies. Correlations become increasingly difficult and tenuous as distances between samples increase. |