S1+S2 Potential The total hydrocarbon potential Source richness Subject to the combined problems of S1 Range 0 to 1256 (based on mg HC/g yield (genetic potential) i.e. the and S2. maximum theoretical HI Kerogen type free and kerogen-bound below) rock hydrocarbons. Tmax °C Based on maximum height of the Maturity Depressed values indicate either migrated 300°C to 600°C/650°C S2 peak in temperature program. hydrocarbons or thermally labile (S-rich) (Rock-Eval 6) Kerogen type Temperature corresponding to kerogen (Snowdon, 1995). For multiple the maximum amount of peaks in S2, the one with the highest signal hydrocarbons generated from the is assigned Tmax. Anomalously low and cracking of kerogen (S2). high Tmax values can result for these Temperature measured outside mixed sources and from drilling additives. of the furnace in earlier High (>500°C) Tmax values can also result instruments e.g. Rock Eval II. from mineral decomposition. Reproducibility is typically ±2°C. Tpeak °C (Rock-Eval 6) Based on maximum height of S2 Used in the see Tmax Tpeak is approximately 40°C peak in temperature program. derivation of kinetic greater than Tmax at a True temperature corresponding parameters where heating rate of 25°C/min to the maximum rate of absolute temperature hydrocarbons generated from the is needed cracking of kerogen. Temperature measured inside of the oven at the base of the sample e.g. Rock Eval 6 instrument HI Hydrogen Index, Amount of hydrocarbons Source richness HI > 300 indicates oil-proneness. For rocks 0 to 1256. The theoretical released on pyrolysis (S2) Kerogen type with TOC < 3% the HI can be suppressed maximum HI of 1256 mg hydrocarbons normalised to TOC. Maturity by up to 100% (see mineral matric mg HC/g TOC is obtained for (S2)/g TOC suppression under S2), resulting in the true 100% conversion of the HI = 100 * S2/TOC hydrocarbon potential being severely organic matter to underestimated. It is recommended that HI hydrocarbons, assuming the determined on isolated kerogen be used for proportion of carbon in the organically lean rocks. organic matter is 0.83.
S1+S2 Potential mg HC/g rock The total hydrocarbon potential yield (genetic potential) i.e. the free and kerogen-bound hydrocarbons. Source richness Kerogen type Subject to the combined problems of S1 and S2. Range 0 to 1256 (based on maximum theoretical HI below) Tmax °C Based on maximum height of the S2 peak in temperature program. Temperature corresponding to the maximum amount of hydrocarbons generated from the cracking of kerogen (S2). Temperature measured outside of the furnace in earlier instruments e.g. Rock Eval II. Maturity Kerogen type Depressed values indicate either migrated hydrocarbons or thermally labile (S-rich) kerogen (Snowdon, 1995). For multiple peaks in S2, the one with the highest signal is assigned Tmax. Anomalously low and high Tmax values can result for these mixed sources and from drilling additives. High (>500°C) Tmax values can also result from mineral decomposition. Reproducibility is typically ±2°C. 300°C to 600°C/650°C (Rock-Eval 6) Tpeak °C (Rock-Eval 6) Based on maximum height of S2 peak in temperature program. True temperature corresponding to the maximum rate of hydrocarbons generated from the cracking of kerogen. Temperature measured inside of the oven at the base of the sample e.g. Rock Eval 6 instrument Used in the derivation of kinetic parameters where absolute temperature is needed see Tmax Tpeak is approximately 40°C greater than Tmax at a heating rate of 25°C/min HI Hydrogen Index, mg hydrocarbons (S2)/g TOC Amount of hydrocarbons released on pyrolysis (S2) normalised to TOC. HI = 100 * S2/TOC Source richness Kerogen type Maturity HI > 300 indicates oil-proneness. For rocks with TOC < 3% the HI can be suppressed by up to 100% (see mineral matric suppression under S2), resulting in the true hydrocarbon potential being severely underestimated. It is recommended that HI determined on isolated kerogen be used for organically lean rocks. 0 to 1256. The theoretical maximum HI of 1256 mg HC/g TOC is obtained for 100% conversion of the organic matter to hydrocarbons, assuming the proportion of carbon in the organic matter is 0.83.
Rec2016_006.docx