In oil and gas fields studies, determining in-situ stress direction and magnitude is a basic issue. The application of in-situ stress studies in oil and gas fields is to solve problems such as well instability during drilling, to select the safe drill path, to avoid casing damages, and to increase production. This study evaluates the in-situ stress in Asmari formation at Marun oil field. To determine and analyze the in-situ stress, the most appropriate method is employing image logs. Therefore, the image logs for the target wells are interpreted in this study. The image logs are categorized as acoustic and electric logs. This study employs OBMI electric logs and UBI acoustic logs which play an important role in geological and petrophysical interpretations. In structural analysis of oil fields, it is critical to determine the in-situ stress and structural dip when drilling and developing the oil field. This study investigates the relation between the field structure and the region tectonics. The results are calculated based on WSM (World Stress Map) project. The Marun Anticline oil field is located in the middle area of Zagros fold-trust belt at south of Dezful embayment and along Ramin and Aghajari Anticlines. Employing subsurface data and analysis of OBMI and UBI image logs, this study investigates the association of the structure with regional tectonics, along foldings and fractures in Marun Anticline. The preliminary results obtained by well log data is used to analyze layering, in-situ stress direction, mud loss in drilling, and fractures related to folding and their effects on permeability. The results of this study demonstrated that fractures in Marun Anticline are a combination of longitudinal, transverse and diagonal fractures. Analysis of mentioned data suggested that the highest density of fractures happens in sub-layers of 10, 20, 30, 40 and 50. The maximum horizontal stress direction in this area occurs along N57W. At the end, the directions of the specified horizontal stresses are compared with the directions of stresses in Zagros.
