Sedimentary environment, diagenetic processes and sequence stratigraphy of the Fahliyan Formation in Jufair field, Abadan Plain, southwest of Iran
Subject Areas : زمین شناسی نفت
SeiedAghil Hoseini
1
*
,
Davood Jahani
2
,
Nader Kohansal Ghadimvand
3
1 -
2 - Department of Geology , North Tehran Branch, Islamic Azad University, Tehran, Iran
3 - Department of Geology, North Tehran Branch, Islamic Azad University, Tehran, Iran
Keywords: Sedimentary environment, Diagenetic processes, Sequnce stratigraphy, Fahliyan Formation, Abadan Plain, Jufair Field,
Abstract :
The Fahliyan Formation, of Lower Cretaceous age (Berriasian-Barremian), is one of the important hydrocarbon reservoirs in southwestern Iran. This study focuses on the Fahliyan Formation in a well located in the Jufair oil field in the Abadan plain, aiming to reconstruct the depositional environment, sea level fluctuations, and diagenetic history. To achieve this, 250 thin sections were analyzed for petrographic characteristics. In addition, changes in petrophysical gamma, neutron, and density logs were examined to complement the microscopic results. In the studied well, 12 sedimentary facies from open marine, shoal, lagoon, and tidal sub-environments were identified. The distribution of facies shows that they have deposited in the outer, middle, and inner parts of a homoclinal carbonate ramp. Diagenetic processes in different meteoric, marine, and burial environments have affected the sediments of the Fahliyan Formation. Physical compaction and cementation processes have played the most role in reducing porosity, while dolomitization, stylolitization, and fracturing processes have increased porosity. Analysis of sea level fluctuations during the deposition of the Fahliyan Formation within the framework of sequence stratigraphy revealed two third-order sedimentary sequences in the well, mostly composed of highstand system tract. Reservoir quality assessments indicated that the shoal and tidal flat facies within the highstand system tracts exhibit the highest porosity.