First evidence of the early cretaceous oceanic anoxic events (MBE and OAE1a) in the southern Tethyan margin (NE-Tunisia): biostratigraphy and shale resource system
Abstract The Jebel Oust region (north-eastern Tunisia) recorded two levels of marine black shale in the Lower Cretaceous marly series. Geodynamic evolution, biostratigraphic and Rock–Eval analysies allow classifying those black shales as unconventional shale oil resource systems that were deposited...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
SpringerOpen
2021-03-01
|
| Series: | Journal of Petroleum Exploration and Production Technology |
| Subjects: | |
| Online Access: | https://doi.org/10.1007/s13202-021-01126-0 |
| _version_ | 1797199593024258048 |
|---|---|
| author | Rachida Talbi Ahlem Amri Abdelhamid Boujemaa Hakim Gabtni Reginal Spiller Raymond Levey |
| author_facet | Rachida Talbi Ahlem Amri Abdelhamid Boujemaa Hakim Gabtni Reginal Spiller Raymond Levey |
| author_sort | Rachida Talbi |
| collection | DOAJ |
| description | Abstract The Jebel Oust region (north-eastern Tunisia) recorded two levels of marine black shale in the Lower Cretaceous marly series. Geodynamic evolution, biostratigraphic and Rock–Eval analysies allow classifying those black shales as unconventional shale oil resource systems that were deposited during two oceanic anoxic events: the Middel Barremian Event "MBE" and the Early Aptian Event "OAE1a". Paleogeographic evolution highlights two transgressive–regressive cycles: the first one is Valanginian-Early Barremian, and the second is Late Barremian–Early Aptian. Each black shale deposit occurs at the end of the transgression that coincides with the highest sea level. During the Barreman–Aptian interval, sedimentation was controlled by extensional faults in a system of tilted fault blocks which were reactivated several times. Kerogen is of type I, II origin in black shales and of type III origin in marls. Tmax values indicate "oil window" stage. Average transformation ratio is around 67% and 82%, respectively, in the Lower Aptian and Middel Barremian source rock related to the relatively high thermal maturity degree due to the deep burial of the later. Estimated initial hydrocarbon generation potential is moderate to high. Oil saturation index records an "oil crossover" indicating expelled and migrated hydrocarbons from the organic-rich to the organic-poor facies. The petroleum system of the two mature source rocks with a high hydrocarbon generation potential enclose all elements characterizing a "shale oil hybrid system with a combination of juxtaposed organic-rich and organic-lean facies associated with open fractures". |
| first_indexed | 2024-04-24T07:18:13Z |
| format | Article |
| id | doaj.art-2205e764d47d4f62b02423559511b675 |
| institution | Directory Open Access Journal |
| issn | 2190-0558 2190-0566 |
| language | English |
| last_indexed | 2024-04-24T07:18:13Z |
| publishDate | 2021-03-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of Petroleum Exploration and Production Technology |
| spelling | doaj.art-2205e764d47d4f62b02423559511b6752024-04-21T11:09:25ZengSpringerOpenJournal of Petroleum Exploration and Production Technology2190-05582190-05662021-03-011141559157510.1007/s13202-021-01126-0First evidence of the early cretaceous oceanic anoxic events (MBE and OAE1a) in the southern Tethyan margin (NE-Tunisia): biostratigraphy and shale resource systemRachida Talbi0Ahlem Amri1Abdelhamid Boujemaa2Hakim Gabtni3Reginal Spiller4Raymond Levey5Georesources Laboratory, Center for Water Research and Technologies (CERTE), Technopark of Borj-CedriaGeoresources Laboratory, Center for Water Research and Technologies (CERTE), Technopark of Borj-CedriaGeoresources Laboratory, Center for Water Research and Technologies (CERTE), Technopark of Borj-CedriaGeoresources Laboratory, Center for Water Research and Technologies (CERTE), Technopark of Borj-CedriaCEO Azimuth EnergyEnergy and Geoscience InstituteAbstract The Jebel Oust region (north-eastern Tunisia) recorded two levels of marine black shale in the Lower Cretaceous marly series. Geodynamic evolution, biostratigraphic and Rock–Eval analysies allow classifying those black shales as unconventional shale oil resource systems that were deposited during two oceanic anoxic events: the Middel Barremian Event "MBE" and the Early Aptian Event "OAE1a". Paleogeographic evolution highlights two transgressive–regressive cycles: the first one is Valanginian-Early Barremian, and the second is Late Barremian–Early Aptian. Each black shale deposit occurs at the end of the transgression that coincides with the highest sea level. During the Barreman–Aptian interval, sedimentation was controlled by extensional faults in a system of tilted fault blocks which were reactivated several times. Kerogen is of type I, II origin in black shales and of type III origin in marls. Tmax values indicate "oil window" stage. Average transformation ratio is around 67% and 82%, respectively, in the Lower Aptian and Middel Barremian source rock related to the relatively high thermal maturity degree due to the deep burial of the later. Estimated initial hydrocarbon generation potential is moderate to high. Oil saturation index records an "oil crossover" indicating expelled and migrated hydrocarbons from the organic-rich to the organic-poor facies. The petroleum system of the two mature source rocks with a high hydrocarbon generation potential enclose all elements characterizing a "shale oil hybrid system with a combination of juxtaposed organic-rich and organic-lean facies associated with open fractures".https://doi.org/10.1007/s13202-021-01126-0Oceanic anoxic eventsShale oil systemOpen fractureRock–Eval pyrolysis |
| spellingShingle | Rachida Talbi Ahlem Amri Abdelhamid Boujemaa Hakim Gabtni Reginal Spiller Raymond Levey First evidence of the early cretaceous oceanic anoxic events (MBE and OAE1a) in the southern Tethyan margin (NE-Tunisia): biostratigraphy and shale resource system Journal of Petroleum Exploration and Production Technology Oceanic anoxic events Shale oil system Open fracture Rock–Eval pyrolysis |
| title | First evidence of the early cretaceous oceanic anoxic events (MBE and OAE1a) in the southern Tethyan margin (NE-Tunisia): biostratigraphy and shale resource system |
| title_full | First evidence of the early cretaceous oceanic anoxic events (MBE and OAE1a) in the southern Tethyan margin (NE-Tunisia): biostratigraphy and shale resource system |
| title_fullStr | First evidence of the early cretaceous oceanic anoxic events (MBE and OAE1a) in the southern Tethyan margin (NE-Tunisia): biostratigraphy and shale resource system |
| title_full_unstemmed | First evidence of the early cretaceous oceanic anoxic events (MBE and OAE1a) in the southern Tethyan margin (NE-Tunisia): biostratigraphy and shale resource system |
| title_short | First evidence of the early cretaceous oceanic anoxic events (MBE and OAE1a) in the southern Tethyan margin (NE-Tunisia): biostratigraphy and shale resource system |
| title_sort | first evidence of the early cretaceous oceanic anoxic events mbe and oae1a in the southern tethyan margin ne tunisia biostratigraphy and shale resource system |
| topic | Oceanic anoxic events Shale oil system Open fracture Rock–Eval pyrolysis |
| url | https://doi.org/10.1007/s13202-021-01126-0 |
| work_keys_str_mv | AT rachidatalbi firstevidenceoftheearlycretaceousoceanicanoxiceventsmbeandoae1ainthesoutherntethyanmarginnetunisiabiostratigraphyandshaleresourcesystem AT ahlemamri firstevidenceoftheearlycretaceousoceanicanoxiceventsmbeandoae1ainthesoutherntethyanmarginnetunisiabiostratigraphyandshaleresourcesystem AT abdelhamidboujemaa firstevidenceoftheearlycretaceousoceanicanoxiceventsmbeandoae1ainthesoutherntethyanmarginnetunisiabiostratigraphyandshaleresourcesystem AT hakimgabtni firstevidenceoftheearlycretaceousoceanicanoxiceventsmbeandoae1ainthesoutherntethyanmarginnetunisiabiostratigraphyandshaleresourcesystem AT reginalspiller firstevidenceoftheearlycretaceousoceanicanoxiceventsmbeandoae1ainthesoutherntethyanmarginnetunisiabiostratigraphyandshaleresourcesystem AT raymondlevey firstevidenceoftheearlycretaceousoceanicanoxiceventsmbeandoae1ainthesoutherntethyanmarginnetunisiabiostratigraphyandshaleresourcesystem |