A new method for paleostress study on 3D seismic interpretation data, revealing the tectonic evolution in western Zagros, southern Iran

The stress field and its spatial and temporal changes are critical in various branches of geosciences such as geotechnics, petroleum geology, and geomechanical studies of hydrocarbon-bearing reservoirs. It is also crucial in understanding the geodynamics of the area. This investigation also aims to infer the tectonic evolution of the area, which is important for hydrocarbon production. In this study, a new method for determining the slip direction from 3D seismic interpretation data is used for paleostress studies in one of the hydrocarbon fields in southern Iran. The method is implemented for different horizons with different geological ages employing a non-linear stress tensor inversion scheme. The stress direction remains constant for a long time, starting from the Cretaceous based on the horizon's geological ages. Also, the present state of the stress field is calculated from the focal mechanism of earthquakes obtained from international research centres by the same method. This study showed rotation in the direction of maximum horizontal stress over time. The maximum horizontal stress direction of NW-SE in the Cretaceous becomes NE-SW in the present day. Due to the lack of data, it is not possible to conclude whether this rotation is clockwise or counterclockwise, urging more detailed studies.