Naslov
Depositional facies controls on the diagenesis and reservoir quality of the Messinian Qawasim and Abu Madi formations, onshore Nile Delta, Egypt

Autori
Leila, Mahmoud ; Moscariello, Andrea ; Šegvić, Branimir

Izvornik
Geological journal (0072-1050) 54 (2018), 3; 1797-1813

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Abu Madi ; diagenesis ; Messinian ; Nile Delta ; Qawasim ; reservoir quality

Sažetak
The Messinian Qawasim and Abu Madi formations are the main hydrocarbon exploration targets in the onshore Nile Delta. Qawasim Formation constitutes prograditional deltaic system from prodelta and distal delta‐front (distal deltaic facies) to proximal delta‐front and delta‐plain (proximal deltaic facies). Abu Madi sediments on the other hand change upward from continental subaerial gravity‐flow and fluvial facies to marginal‐marine estuarine facies. The seismic attribute (RMS amplitude) and petrophysical analyses revealed that solely the Qawasim proximal deltaic and Abu Madi fluvial facies define the potential reservoir targets. The reservoir quality of the Qawasim distal deltaic and the Abu Madi estuarine facies was completely deteriorated during eodiagenesis by calcite and glauconite cementation (mean > 7.3% and 4.5%, respectively). Conversely, the depositional setting of the Qawasim proximal deltaic and Abu Madi fluvial facies favoured a precipitation of scattered eodiagenetic calcite (mean < 2.5%), which supported the facies framework against mechanical compaction and preserved the intergranular volume (IGV). Chemical compaction, smectite infiltration, quartz cementation, and clay minerals authigenesis were more pronounced in the relatively deeper Abu Madi fluvial facies. These burial attributes caused a large‐scale reservoir heterogeneity. Therefore, the relatively shallower Qawasim proximal deltaic facies presents the best reservoir target in the Messinian sequence of the Nile Delta. This study reveals that in analogous systems, the depositional environment largely controls the diagenetic pathways and, hence, the reservoir quality.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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