Hydrocarbon Exploration Using High Resolution Local Passive Seismic Tomography; An application to the Dehdasht region, south-west Iran

With the growing global demand for energy resources, passive seismic tomography started to be used widely for producing 3D images of the sub-surface structures using micro-earthquakes as a new revolutionary method in hydrocarbon exploration even in difficult mountainous terrains areas. In this study we used non-linear travel-time tomography technique to resolve seismic velocity structures in the Dehdasht area/Zagros region. The study area can be considered as an excellent place for studying passive methods due to frequent occurrence of small to moderate earthquakes. More than 8000 small seismic events, micro-earthquakes, were detected to image a 3D volume of Vp and Vs sub-surface structures. The final 3D VP and Vp/VS velocity models reveal several high and low velocity anomalies in the upper 3.0 km of the study area where shallow low-angle thrusts and synclines signify the complexity of the volume studied. We present the results of local passive seismic tomography in one of the most prone structures of the Earth for the hydrocarbon exploration; showing that a 3D image of the given region can be obtained for hydrocarbon exploration purposes at lower cost compared to classical 2D seismic control source studies.