Biostratigraphy of the Sarvak and Ilam formations in Abteymoor Oil Field (Wells no. 1 and 14)

In order to carry out biostratigraphic studies on Sarvak and Ilam formations, two subsurface sections in wells 1 and 14 of Abteymoor oil field were selected in the south of Dezful embayment. Sarvak Formation in well #1 has 812.98 (m) thickness and in Well No. 14 only 234 (m) of this formation was drilled, in terms of lithology the Sarvak Formation consists mainly of limestone with dolomitic and clay interbeds. Its lower boundary in Well # 1 with Kazhdumi Formation is conformable but in Well # 14 it is unclear. The upper boundary is disconformable with Ilam Formation in both wells. Ilam Formation in two wells of 1 and 14, has thickness of 151.72 and 136 (m) respectively and in terms of lithology, it consists of limestone and shaley, marly and dolomitic limestone interbeds. The upper boundary of Ilam Formation with Gurpi Formation is conformable with sharp changes in lithology. In biostratigraphy studies 71 species were detected which belong to 57 genera of foraminifera, a biozones (biozone 1) in Ilam Formation and three biozones (biozones 2, 3 and 4) were identified in Sarvak Formation. They include: 1-      Rotorbinella-Pararotalia Assemblage Zone 2-      Nezzazatinella picardi-Dicyclina schlumbergeri Assemblage Zone 3-      Rotorbinella mesogeensis Total Range Zone 4-      Nezzazata-alveolinid Assemblage Zone Based on identified biozones, age of Sarvak Formation is considered as Cenomanian- Turonian and the age of Ilam Formation is Designated as Santonian- Campanian?