Callovian source rock modelling as encountered in the Chotts Basin and the Gulf of Gabes: Generation and maturity distribution

The Callovian series are considered as proven to have sourced the reservoirs of the Ezzaouia and El Bibene fields of south-eastern Tunisia. However, its potential is still subject of debate associated with its paleogeographic distribution along with its burial and thermal histories. In this study, 17 wells drilled in the southern Chotts Basin and the Gulf of Gabes were used to model the burial and maturity histories of the Callovian series and estimate volumes of generated and expelled hydrocarbons.The Callovian organic material is generally marked by type II-III with low to moderate contents (up to 1%). The Callovian successions located in the north-eastern part of the Chotts Basin bear low total organic carbon (TOC) contents averaging 0.25%.TOC content and petroleum potential maps were generated with the Callovian series showing a source po-tential, southwards of the study area.Modelling results show variable burial and thermal histories depending on the location of selected wells. The series with source rock potential in wells located south of the Chotts Basin are in a an early to mid-mature stage with substantial amounts of generated oil. The Callovian series in the Gulf of Gabes are marked by advanced thermal maturity with gas generation being initiated since 10My. A maturity map is proposed for the Callovian series underlying four different stages of maturity.