Generation temperatures for oils sourced from sulfur-rich kerogens using aromatic and light hydrocarbon isomersAuthor(s): Belle Richard
The link between isomer ratios of some hydrocarbons and temperature can be utilised to gauge thermal maturity and direct petroleum exploration. In the literature, the C7 Dimethylpentanes (DMPs) are widely utilised to determine the temperature at which produced oils are generated. These light hydrocarbons are very helpful, but source mixing, thermochemical sulphate reduction, water washing, and evaporative fractionation can all have an impact. For oils derived from sulfur-rich kerogens (i.e., Type II-S), proper temperature computation is especially crucial because oil formation starts earlier at lower temperatures due to an early shattering of carbon bonds. Standard maturity techniques may underestimate the thermal maturity of Type II-S oils due to the sulphur enrichment of kerogen; consequently, alternative techniques specific to sulfurrich sources, such as the aromatic Methyldibenzothiophene (MDBT) isomers, are required to precisely determine generation temperatures and maturity. There are few studies connecting lighter hydrocarbons to longer-chained aromatic hydrocarbons. In this study, the 4-MDBT/1-MDBT ratio is used to directly compute the maturity and generation temperatures for Type II-S oils by integrating the light hydrocarbon DMPs and aromatic, sulfur-bearing MDBTs.