Microfacies, Diagenetic and Depositional Environment of Kazhdumi Formation (Aptian-Albian), Dezful Embayment, Zagros, NW Iran

Soleimani B

doi:10.4172/2329-6755.1000154

Abstract

Facies determination of the Kazhdumi Formation in Solabdar and Chilingar oil wells which are the oldest Iranian oil wells is very important since the Kazhdumi was known as a source rock in these fields. Lithological composition of this formation is limestone, shale and glauconite bearing sandstone in the base which is an obvious sign of disconformity between Kazhdumi and Dariyan formations. The Diagenetic effective processes in this area include: dissolution, substitution (hematitization, glauconitization), micritization and bioturbation, cementation, compaction, stylolitization and porosity (interapartical, moldic, intercrystaline, channel). These processes are in relation to diagenetic environments such as meteoric, marine phreatic and deep burial. Kazhdumi Formation in the studied fields is composed of seven carbonate facies and two clastic facies (shale and sandstone) as follows: bioclast wackestone/ packstone- bioclast packstone– bioclast wackestone/packstone–sandstone (lagoon facies) and bioclast wackestoneglobigerin, wackestone (planktonic wackestone)/crinoidal globigerina wackestone –oligosteginid wackestone (open marine facies). By considering these facies, it is suggested lagoon and open marine sedimentary environments for Kazhdumi Formation in the studied fields.

Highlights

The Kazhdumi Formation was considered as a part of the ammonite-bearing shale in old reports and sometimes it has been called the Ebad Formation
The field has located between Gachsaran field in the North, Bibi-Hakime field in the south, Garnagan field in west and Chahar Bishe field in the east (Figure 1). It can be concluded from the aerial photographs and the geology and topography maps of the southwest Iran, that the region of Fars and Lorestan are higher than the middle section (Dezful Embayment)
While crinoid and bentic forams are belong to high energetic part of the lagoon. This facies is found in the base of Kazhdumi Formation that is equal to Bourgan sandstone flames in south of Persian Gulf

Summary

Introduction

Khalili [7] has perused a rather comprehensive study on Kazhdumi, Sarvak, Ilam, Surgah (Bangestan Group) formations in south and southwest of Iran and in this regard, has provided a lithofacies map for each chronostratigraphy unit and has compared the mentioned unit biozones in drilled wells and surface sections with each other. The fields were used in this paper to study Kazhdumi Formation are located in the south branch Dezful Embayment, including the Sulabdar and Chilingar fields. The field has located between Gachsaran field in the North, Bibi-Hakime field in the south, Garnagan field in west and Chahar Bishe field in the east (Figure 1) It can be concluded from the aerial photographs and the geology and topography maps of the southwest Iran, that the region of Fars and Lorestan are higher than the middle section (Dezful Embayment). There has not been reported any fault between Garangan, Chilingar

Methodology

Conclusions