Seismic Sequence Stratigraphic Model and Hydrocarbon Potential of Yamama Formation in Al-Fao Area, Southeastern Iraq

Abstract

One key step when interpreting seismic reflection data is sequence stratigraphy, which has improved with well logs and seismic data. By analyzing the different layers of sediment and rock, we can better understand the geologic history of an area and make more accurate predictions for hydrocarbon exploration. The current research focuses on interpreting seismic lines from the 2D seismic surveys conducted in the Al-Fao area and data from wells in the Siba gas field to construct a stratigraphic model within the Yamama Formation, to identify hydrocarbon traps and determine the most promising zones for hydrocarbon exploration. Yamama Formation is divided into two main units representing transgressive and regressive facies deposited in highstand system tract. Six seismic facies were identified (wavy, mound shape, oblique parallel, sigmoid, chaotic, and parallel), which reflected the deposition of Yamama Formation in a ramp setting with a gentle slope. Instantaneous phase attribute was utilized, which focused on the lateral changes of seismic facies and provided detailed information about the architecture of Yamama Formation depositional basin. The results of the seismic attributes analysis included identifying carbonate buildups and progradation stacking patterns with the presence of direct hydrocarbon indicator. Three main seismic stratigraphic indexes representing potential stratigraphic traps have been identified. These three stratigraphic features reflect the facies of shoal carbonate sediments in the last depositional cycle of Yamama Formation (Highstand). The stratigraphic model showed the best image of the depositional environment of Yamama Formation that corresponds with the seismic data interpretation and identifies the promising hydrocarbon traps.