A new approach to interpreting relationship between Rock-Eval S2 and TOC data for source rock evaluation based on regression analyses

To evaluate the relationship between total organic carbon (TOC) and Rock-Eval S2 (petroleum potential) of petroleum source rocks, atotal of 180 outcrop samples from the black organic matter–rich facies of Mesozoic strata from a locality of southwest of Iran wereinvestigated using Rock-Eval VI pyrolysis and Leco Carbon Analyzer. The linear regression is applied to determine the correlationbetween Leco TOC and Rock-Eval S1 and S2. The accuracy of the proposed model by this method has approximately 95% conformityaccording to the Rock-Eval S2 and Leco TOC data (TOC = 0.492 + 0.174 S2). Then, by using the P value method, it was determinedthat TOC is a function of S2 and S1 only causes the fluctuations. By means of sensitivity analysis of TOC with respect to S1 and S2, itwas shown that TOC has a linear relationship with S2 and does not have any noticeable correspondence to S1. The result of this studycan be used to evaluate petroleum potential (S2) of organic matter–rich facies by using TOC obtained by Leco Carbon Analyzer. Forthe studied samples from the organic matter-rich facies, organic carbon richness is a quality and quantity index of petroleum potential.