Evaluating the Asmari Fractured Reservoir: Findings from FMI and Petrophysical Logging

Background and Objective: The Asmari Formation presents substantial challenges in reservoir management due to its structural complexities. Traditional core sampling methods fall short of accurately characterizing the fractured regions, impacting the efficacy of reservoir exploitation. Current study aims to enhance the understanding of the Asmari reservoir’s structural and fracture complexities to improve well-test analyses and establish a detailed structural model for fracture characterization. Materials and Methods: The Formation Micro Imager (FMI) and geological logs utilized in well ZE-15, located within the Asmari Formation, for our experimental design. The FMI data, collected between depths of 4374 and 4640 m, was instrumental in assessing structural dips and mapping natural fractures. This approach facilitated a comprehensive analysis of fracture properties and structural orientation, incorporating statistical analyses to interpret the data accurately. Results: The FMI logging revealed a consistent structural dip of 33 degrees towards S62W across the Asmari Formation. Three main fracture zones were identified at depths of 4377-4459 m (Zone 1), 4459-4480 m (Zone 2) and 4480-4574 m (Zone 3), displaying a predominant WNW-ESE strike direction. This orientation correlates with the Zeloi structure’s longitudinal alignment and the bedding strike. Further, elliptical borehole shapes observed in FMI images and caliper readings suggested the direction of minimum and maximum horizontal stresses, providing insights into the stress orientations affecting the formation. Conclusion: The current study successfully delineated the structural and fracture complexities within the Asmari reservoir, offering crucial insights into its stress orientations and natural fracture systems. This enhanced understanding is vital for optimizing reservoir exploitation strategies and improving recovery rates from this challenging geological formation.