New findings about the stratigraphy of Neritic Ilam Formation in Ab- Teymur oil field.

Abstract :

Microfacies and stratigraphy  of  Ilam  formation  in well  No.  14  in  Ab – Teymur  oil  field whitin  North  Dezful  embaymet  has  been  done in  this  study.

In  this  study  185  thin  sections  from  Ilam formation with  thickness  of  143 m. was  studied.This  unit  mainly consists of brown limestones (Wackstone -Packstone) and  microfossils are related to the Biozone No.30 (Wynd 1965).Based on the obtained microfossils the age of Ilam Fm. is Santonian and sedimentary environment is  related  to the open  marine from continental  slope  to upper  part  of open marine( neritic facies ).

The type section of Ilam formation is located  in  the north east flank of Kabir Kuh  Anticline. The formation thickness   is  190 m.  with   pelagic facies  rich  in  planktonic foraminifera such as : Globotruncana spp.  and  oligosteginids.

It  is  important  to  note  that  this  pelagic  facies is   mainly  distributed in  the Lurestan area  while  in Dezful embayment and Fars areas  mostly  consists of  neriti c facies, therefore  there isn’t any reference  section  for the   neritic Ilam  formation  in  the  mentioned  areas.

With regard to full core coverage of studied section  in  Dezful  embayment  and  fars  areas , this  subsurface  section  for  the  first  time  is  suggested  as  a  Neritic  Ilam  Reference  Section by  authors.