Contemporary tectonic stress pattern of the Persian Gulf Basin, Iran

Abstract

Abstract The contemporary crustal stress pattern is important to several aspects of earth sciences such as reservoir geomechanics, neotectonic deformation and geodynamic modelling. The Persian Gulf Basin is a petroliferous region in southern Iran that hosts hundreds of petroleum wells and, hence, the knowledge of the present-day stress is critical for any exploration and production in this region. In addition to geo-resources, this region has a great economic importance and the in-situ stresses provide key insights on neotectonic and seismic hazard of the basin. However, there is limited in-situ stress information in the Persian Gulf region. In this study, we analyse >8\u202fkm of borehole image logs in 20 wellbores in the Persian Gulf in order to provide a clear picture of the stress pattern in this region. Our wellbore stress analyses provide 35 quality-ranked maximum horizontal stress orientations (SHmax) data records. In addition, we compile 27 earthquake focal mechanisms in the study region from different seismic catalogues and published literature, and present the first comprehensive quality-ranked in-situ stress map of the Persian Gulf Basin with 62 data records, which can be used as a valuable source of information for future exploration and seismic hazard assessment. The resulting database suggests that the SHmax azimuth in central and western Persian Gulf is NE-SW (parallel to the Arabia-Eurasia tectonic plate convergence), which demonstrate the key role of relative plate motion in the present-day stress pattern of these areas. However, the SHmax azimuth in the eastern part of the study area is NW-SE, which is different from the central and western Persian Gulf. The NW-SE SHmax azimuth is consistent with other geological and geophysical observations that suggest an indentor model for Musandam Peninsula (Oman) in the Zagros-Makran syntaxis.