Sequence stratigraphy of the petroliferous Dariyan Formation (Aptian) in Qeshm Island and offshore (southern Iran)

P Mansouri-Daneshvar,A Mahboubi,R Moussavi-Harami,A Feizie,M H M Gharaie

doi:10.1007/s12182-015-0027-8

P Mansouri-Daneshvar, A Mahboubi + Show 3 more

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https://doi.org/10.1007/s12182-015-0027-8

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Abstract

After sea level rises during the Early Cretaceous, upper parts of the Khami Group sediments (Fahliyan, Gadvan, and Dariyan Formations) deposited over Jurassic sediments. The Lower Cretaceous (Aptian) Dariyan Formation (equivalent to the Shu’aiba Formation and Hawar Member of the Arabian Plate) carbonates, which have hydrocarbon reservoir potential, form the uppermost portion of the Khami Group that unconformably overlays the Gadvan Formation and was unconformably covered by the Kazhdumi Formation and Burgan sandstones. Detailed paleontological, sedimentological, and well log analysis were performed on seven wells from Qeshm Island and offshore in order to analyze the sequence stratigraphy of this interval and correlate with other studies of the Dariyan Formation in this region. According to this study, the Dariyan Formation contains 14 carbonate lithofacies, which deposited on a ramp system that deepened in both directions (NE—wells 5, 6 and SW—wells 1, 2). Sequence stratigraphy led to recognition of 5 Aptian third-order sequences toward the Bab Basin (SW—well 1) and 4 Aptian third-order sequences toward Qeshm Island (NE—wells 5 and 6) so these areas show higher gamma on the gamma ray logs and probably have higher source rock potential. Other wells (wells 2–4 and 7) mainly deposited in shallower ramp systems and contain 3 Aptian third-order sequences. On the other hand, rudstone and boundstone lithofacies of studied wells have higher reservoir potential and were deposited during Apt 3 and Apt 4 sequences of the Arabian Plate. The Dariyan Formation in Qeshm Island (well 6) and adjacent well (well 5) was deposited in an intrashelf basin that should be classified as a new intrashelf basin in future Aptian paleogeographic maps. We interpret that salt-related differential subsidence, crustal warping, and reactivation of basement faults of the Arabian Plate boundary were responsible for the creation of the intrashelf basin in the Qeshm area.

Highlights

The Persian Gulf contains 55–68 % of the world’s recoverable oil and more than 40 % of gas reserves (Konyuhov and Maleki 2006)
The objectives of this study are to interpret depositional sequences by collecting petrographical studies of cores, cuttings, and log data and correlation of sequences between the Iranian part and the Arabian Plate in a vast area of Qeshm Island and offshore in southern Iran (Fig. 2) that can give a better clue in paleogeography during the Aptian time
The Dariyan Formation in Qeshm Island and offshore is equivalent with the Hawar Member and Shu’aiba Formation of the Arabian Plate and contains 14 carbonate lithofacies which deposited on a carbonate ramp system

Summary

Introduction

The Persian Gulf contains 55–68 % of the world’s recoverable oil and more than 40 % of gas reserves (Konyuhov and Maleki 2006). Cretaceous carbonate platforms encompass approximately 16 % of world’s hydrocarbon reservoirs developed in the Tethyan region including the Persian Gulf (Scott et al 1993). The Lower Cretaceous (Aptian) Dariyan Formation comprises the uppermost portion of the Upper Jurassic to Lower Cretaceous Khami Group (James and Wynd 1965). This formation is predominantly composed of limestones deposited on a passive margin (Sharland et al 2001) and its upper part is equivalent to the Shu’aiba Formation in the Arabian Plate region.

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