Sequence stratigraphy and the Yamama Formation platform in Southern Iraq

Hussein Sh.  Aoudah

doi:10.52716/jprs.v15i1.884

Authors

Hussein Sh. Aoudah Ministry of Oil, Oil Exploration Company, Baghdad, Iraq

DOI:

https://doi.org/10.52716/jprs.v15i1.884

Keywords:

Sequence stratigraphy and Seismic Interpretation, Carbonate ramp, Yamama and Sulaiy formation, Geological model, Early Cretaceous, South Iraq

Abstract

The Yamama Formation consists of two types of sediments (granular units) consisting of Oolitic and Peloidal grainstone in addition to benthic Foraminifera (reservoir units), which grow towards the center basin during Highstand conditions within the environment confined between (Inner-Mid Ramp), and that they represent a shallowing upward cycle.

Granular sediments formed on top of a base consisting of mud-supported limestone (impermeable rocks) to create the second type of sediments that formed during transgressive conditions, which extend over most of the ramp platform and increase the mud support towards the outer ramp. Yamama Formation consists of multiple reservoir units separated by impermeable rock units. Reservoir units with high hydrocarbon potential are considered because petroleum systems are available. In southern Iraq, they are considered an exploratory target within the deposits of the early Cretaceous period. The study area contains (SS-3, SS-2, SS-1, and LL-1) wells. Yamama Formation is divided into four sub-cycles (YA, YB, YC, and YD). The structural maps represent the stratigraphic units of the Yamama Formation by interpreting the data of the seismic cube, which indicated that (the SS and LL) fields represent a structural axial, whose axis extends north-south. SS field consists of two domes and three wells in the southern dome penetrated Yamama Formation, but the northern dome is the most closed, with dimensions (14 x 10) km with closure of about (60) meters, no borehole has been drilled in it, which makes it an exploration target. Yamama Formation in the LL field penetrated by the LL-1 well only and shows the existence of a structural closure with dimensions (4 x 2.5) km and a closure of (30) m. The seismic stratigraphic interpretations explained the development of the Yamama Formation platform, which contributed to the formation of three stratigraphic traps.

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