Pore types distribution and their reservoir properties in the sequence stratigraphic framework: a case study from the Oligo-Miocene Asmari Formation, SW Iran

Gharechelou, Sajjad; Daraei, Mehdi; Amini, Abdolhossein

doi:10.1007/s12517-015-2141-8

Cited by 9 publications

(1 citation statement)

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“…Several studies have been carried out on microfacies, especially addressing the depositional environments and sequence stratigraphy of the Asmari Formation (e.g. Motiei, 1993; Gharechelou et al, 2016 and2018). However, the extensive regional distribution of this formation in the Zagros Basin, its paleo-climate and tectonic setting causes a large variability in microfacies that subsequently were affected by diagenetic processes.…”

Section: Introductionmentioning

confidence: 99%

Depositional environment and diagenesis of Asmari Formation in the well-A (oilfield at western Lorestan basin) and Syah-koh Anticline (Zagros fold–thrust belt, west Iran): microfacies, sequence stratigraphy and geochemistry

Mohammadi¹,

Gharechelou²,

Mozafari³

et al. 2021

Preprint

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The Asmari Formation (Oligocene-Miocene), as one of the main carbonate petroleum reservoirs of the Middle East, represents strongly variable reservoir quality on regional and local scale. One outcrop analogue (Syah-koh Anticline) and a well-A (oilfield at western Lorestan basin), both situated in western Iran, were investigated to address the reservoir characteristics. The 12 microfacies identified reflect deposition on a broad carbonate ramp reflecting an outer, mid and inner ramp setting. Three third-order depositional sequences are deduced based on interpreted Gamma-ray, sonic logs and stratal stacking patterns. The identified sequences and existence of a thicker evaporite succession in well-A points to more restricted depositional conditions with reduced connection to the open sea from the Syah-koh Anticline towards well-A. The diagenetic modifications revealed micritization, dissolution, cementation, fracturing, dolomitization and compaction. Petrographic and δ13C and δ18O analysis of cements points towards marine, meteoric and burial diagenetic alteration, whereby the cements with δ13C and δ18O values similar to those of enclosing micrite (0 to -2‰ V-PDB) reflect a marine diagenetic environment. The micrite phases enriched in aforementioned isotopes resulted from evaporation which is supported by widespread associated dolomitization. The J trend present in the δ13C and δ18O cross plot reflects the meteoric diagenetic overprint. The cements with highly depleted δ18O signatures (<-10‰ V-PDB) are linked to burial diagenetic processes. The isotopic values are in agreement with the luminescence characteristics of the cements including dull for marine, alternating bright and dull zones for meteoric and bright for burial cements.

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Section: Introductionmentioning

confidence: 99%