Stratigraphy and Palaeontology
Parinaz Rasolui Ghadi; Mehdi Sarfi; Seyed Mohsen Aleali; Zahra Maleki
Abstract
Identification of key sequence stratigraphic surfaces is a crucial task in geological characterization of hydrocarbon reservoirs. The uppermost Jurassic–lower Cretaceous carbonate successions of the Manifa member and Fahliyan Formation are as an important oil reservoir of Northwestern Persian Gulf. ...
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Identification of key sequence stratigraphic surfaces is a crucial task in geological characterization of hydrocarbon reservoirs. The uppermost Jurassic–lower Cretaceous carbonate successions of the Manifa member and Fahliyan Formation are as an important oil reservoir of Northwestern Persian Gulf. This study addresses the application of GR D-INPEFA curve to discriminate and correlate key stratigraphic surfaces and sequences of the studied carbonates in five wells a giant oil field of the Persian Gulf. To achieve this goal, identified key stratigraphic surfaces of core and thin sections were compared with interpretation of GR D-INPEFA curve. From sequence stratigraphic point of view and based on the results from geological studies, the Late Tithonian-Neocomian sequence has been discriminated into four third-order sequences which are described and interpreted. The top sequence boundary of the Manifa carbonate corresponds to a significant discontinuity that associated with evidence of karstification and distinct facies variation above and below this key surfaces. Based on the applied D-INPEFA curve, the identified sequence can be effectively discriminated and correlated in the field scale.
Stratigraphy and Palaeontology
Ali Asaadi; Ali Imandoust; Mehdi Sarfi; Mehdi Ghane Ezabadi
Abstract
The Lower Cretaceous Fahliyan Formation is one of the main oil reservoirs in the Persian Gulf. In this study, for investigating facies characteristics, depositional environment, diagenetic features, sequence stratigraphy and describing factors controlling reservoir quality, the integration of the results ...
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The Lower Cretaceous Fahliyan Formation is one of the main oil reservoirs in the Persian Gulf. In this study, for investigating facies characteristics, depositional environment, diagenetic features, sequence stratigraphy and describing factors controlling reservoir quality, the integration of the results from core description, petrographic studies, and petrophysical data was utilized. Nine main facies were recognized and grouped in four facies belts of lagoon, shoal, patch reef and shallow open marine, indicating deposition of the formation in a carbonate ramp platform. Various diagenetic processes that influenced facies, occurred in marine, meteoric, and burial diagenetic realms. Four main pore types have been identified in the reservoir that include interparticle, moldic, vuggy, and microporosity. From the sequence stratigraphy point of view, three third-order sequences which are correlatable within the Fahliyan Formation were identified. The development of grainstone and algal rudstone/floatstone in shoal/ patch reef sub-environment played an important role in developing the high reservoir. In view of their controls on reservoir quality and pore system, diagenetic features can be categorized into two classes: (1) diagenetic processes enhancing reservoir quality that include dissolution and fracturing, and (2) diagenetic processes reducing reservoir quality that include cementation and compaction.
Stratigraphy and Palaeontology
Mohammad Sharifi; Ebrahim Ghasemi-Nejad; M. Akhtari; Mehdi Sarfi; Mohsen Yazdi-Moghadam
Abstract
The Bazyab Formation is one of the Cretaceous rock units in the Khor and Byabanak area. In this study we investigated palynological content of the Bazyab Formation at the Bazyab stratigraphic section where it is up to 1067 meters thick and consists of marlstones, shales, sandstones, limestones and sandy ...
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The Bazyab Formation is one of the Cretaceous rock units in the Khor and Byabanak area. In this study we investigated palynological content of the Bazyab Formation at the Bazyab stratigraphic section where it is up to 1067 meters thick and consists of marlstones, shales, sandstones, limestones and sandy limestones, claystone, shale and interlayers of limestone. The formation at this section is confined conformably between Shah-Kuh Formation at the base and Debarsu Formation at the top. A total of 40 rock samples have been collected from the formation and investigated for their palynological contents. The obtained palynological data resulted in detection of twenty-nine genera and54 species of marine dinocysts alongside with 20 genera and 29 species of terrestrial palynomorphs (spores and pollens). An age of Aptian –Albian is constrained for the formation in this section on the evidence of recorded palynomorphs. Based on high frequencyof inner neritic dinocysts, planktonic foraminifers and mudstone and wackestone facies of the carbonate beds, an inner shelf sedimentary environment was suggested as the depositional environment of the Bazyab Formation.
