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Diagenetic Impact on Polyphase Fault Zones Drain Properties in Micro-Porous Carbonates (Urgonian – SE France)
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, Fifth International Conference on Fault and Top Seals, Sep 2019, Volume 2019, p.1 - 5
Abstract
Fault zones can act as drains or barriers depending of their architecture, mechanical and diagenetic evolution. Carbonates are very sensitive to diagenetic processes. When they are affected by faults, impact on reservoir properties is enhance. The study focalized on 2 polyphased faults affecting Lower Barremian microporous platform carbonates (Urgonian facies). We realized porosity measurements, observed 92 thin sections under cathodoluminescence, analyzed micrite micro-fabric with SEM and micro-sampled 189 O and C isotopic measurements to determine the diagenetic evolution of both host rock and fault zones. Our result reveal a strong decrease of porosity towards the fault planes. We identified seven cementation phases and 2 different micrit microfabrics from diagenetic analysis. The C and O measured isotopic values ranging from −7.2 to +1.42‰ for δ13C and from −10.40 to −3.65‰ for δ18O. The cross-cutting, overlap and superposition principles allowed to realize the fault zones and host rock paragenesis. Studied Urgonian carbonates have been affected by 3 diagenetic events divided in pre-faulting and fault-related stages impacting reservoir properties during the early stages of fault activity.
- 08 Sep 2019