Writers : Ghasemi Noghabi,maryam ;Supervisor: R,Moosaviharami.M,Najafi
Refference : Msc.Thesis-Ferdowsi University of Mashhad
Publishing Year : 1385

Abstract :

Aitamir Formation in Mozduran to Shurijeh area arid Gonbadli, Khangiran gas fields consists of siliciclastic and carbonate rocks. The lower contact of Aitamir Formation with Sanganeh Formation is gradational but the upper contact with Abderaz Formation is disconformable. Based on paleontological studies, the age of this formation is Albian Cenomanian. In this study, 7 stratigraphic sections were measured at Mozduran (355 meter), Padeha (308 meter), Shurijeh (125 meter), Gonbadli well 9 (500 meter), Khangiran well 6 (450 meter), Khangiran well 35 (600 meter), Khangiran well 40 (500 meter).
Aitamir Formation in surface sections divided into 3 parts and in subsurface sections into 5 parts.
Sandstones in the Aitamir Formation are mostly very fine to medium grain, subangular to rounded and mature to submature. These sandstones are composed of quartz (mostly monocrystalline), feldspare (mostly K- feldspar), sedimentary rock fragments (sandstones), opaque minerals, zircon, mica, shell fragments and glaucony. Limestones consists of skeletal debris of pelecypod, echinoderm, biyozoan, gastropod, foraminifera and nonskeletal allochem (ancoid, peloid, intraclast and ooid).
Cement in sadstones and limestones are mostly spary calcite.
Sandstones is composed of two different petrofacies (Al) Medium to fine sand, carbonate and fe oxide, submature-mature, opaque mineral, fossil and glaucony, lithic arkose. (A2) V. fine to medium sand, carbonate and fe oxide, submature- mature, opaque mineral and glaucony, lithic arkose. Mud rocks petrofacies consists of shale and siltstone. Carbonate petrofacies composite of facies (C1) Bioclastic and little glaucony, packstone (C2) Little uncoidal and glaucony, bioclastic packstone (C3) Bioclastic wackstone.
One of the majore components in all siliciclastic facies in Aitamir Formation. Based on maturation, the glauconies in this formation can be divided into slightly evolved, evolved and highly evolved. Morphological analysis of glaucony lead to sepration of two types (allochthonous and autochthonous). Rate of maturity and frequency of glauconies increased upward in transgressive system tract (TST) and reached to maximum in MFS.
But in highstand system tract (HST! the rate of maturity and frequency of glauconies decreased.
Morphology of glaucony in Aitamir Formation type II, III. Therefore, Aitamir Formation has pontential reservoir.
Based on lateral and vertical fades variation in the study area, it is interpreted that the siliciclastic deposits deposited in lagoon shallow open marine environments and carbonate deposits deposited in lagoon to open marine environments.
In mozduran, Gonbadli well 9, Khangiran well 6 sections five depositional sequence (DS), in Padeha section three depositional sequence (DS), in Shurijeh section two depositional sequence (DS), in Khangiran well 35,40 sex depositional sequence have been recognized.
Depositional sequence in all sections is type (1) (SB1). Interpreted sea-level curve during Cenomanian Time and only during the fall of sea level can be correlated with global sea level curve. Paleogeography reconstruction indicates that the siliciclastic grains in the Aitamir Formation may have had a source from southeast Kopet Dagh Basin.
The majore evidence for diagenetic features in siliciclastic rocks during stage of eogenesis are mechanical compaction, cementation, alteration, glaucony and during stage of mezogenesis chemical compaction, dissolution, replacement and during stage of telogenesis fracture. Diagenetic process is affected the carbonate rocks during stage of eogenesis are mechanical compaction, cementation, micritization, glaucony, neomorphism and during stage of mezogenesis chemical compaction, cementation (with poikilotopic, blocky, granular, syntaxial), dissolution and during stage of telogenesis fracture.

Subject List : Sequence Stratigraphy