TITLE:
Investigating the Impress of the Active Tectonics and the Rate of Fractures in Ilam Formation, Fars Area, SW Iran
AUTHORS:
Reza Poursoltani, Mohsen Pourkermani, Koros Yazdjerdi, Mahmood Almassian
KEYWORDS:
Zagros, Iran, Ilam Formation, Field, Carbonate Reservoir
JOURNAL NAME:
Open Journal of Geology,
Vol.6 No.6,
June
29,
2016
ABSTRACT: The evolution of the Active Tectonics of the Ilam Formation (Santonin) form
potential reservoir rocks at oilfields and structures in costal fars. Core and
cuttings samples and wire-line logs from wells in the East Gardan field were
used to investigate microfacies types and porosity evolution. Facies modelling
was applied to predict the relationship between facies distribution and
reservoir characteristics to construct a predictive geologic model which will
assist future exploration in East Gardan field. Microfacies analysis and
electrofacies identification and correlations indicate that the limestones of
the Ilam Formation were deposited in a ramp setting. The ramp developed over
the distal margin of the Santonin proforeland basin, adjacent to the evolved
forebulge. Inner ramp facies are characterized by carbonate bank bioclastic
packstones. Middle ramp facies dominate the Ilam Formation and consist of
bioturbated, massive, dolomitic and bioclastic limestones. Bioclasts include
benthic and planktonic foraminifera. Intense less common Palaeophycus bioturbation
has enhanced the porosity of this facies. Outer ramp deposits consist of
alternating mid-ramp bioturbated bioclastic massive limestones and argillaceous
and marly limestones. Bioclastic packstones and intensively bioturbated
bioclastic limestones of the mid-outer ramp are the primary source of
fabric-selective porosity which is greatly enhanced by diagenetic overprints.