Deciphering the Asmari Formation: Advanced Obmi and Petrophysical Log Analysis for Fractured Reservoir Assessment

Background and Objective: Accessing the Asmari reservoir poses challenges due to its complex structure, affecting well-test analysis accuracy in delineating fracture properties. Traditional core sampling struggles in highly fractured regions, leading to low recovery rates in unfavorable reservoir sections. The main objective of this study is to explore the challenges of accurately characterizing the fracture properties of the Asmari reservoir due to its structural complexities. Specifically, it aims to assess the effectiveness of using advanced borehole imaging tools, namely Oil-Based Mud Imager (OBMI) and Ultrasonic Borehole Imager (UBI), as alternatives to traditional core sampling and well-testing methods. Materials and Methods: Well GS-325 utilized OBMI and UBI tools to explore the Asmari Formation. The study involved a meticulous examination of geological features and structural attributes to understand the factors contributing to the observed thickness. Interpretation included manual dip picking using sinusoid techniques, followed by the classification of dips into bed boundaries and fractures. Results: The investigation revealed geological variations affecting the expected thickness of the Asmari Formation, enhancing comprehension of its complexities. The study identified 517 fractures within the Asmari interval, elucidating structural intricacies within the reservoir. Conclusion: The study demonstrates the successful use of OBMI/UBI imaging tools for identifying fractures and structural details in the Asmari Formation, despite challenges in shifting from oil-based to water-based drilling fluids.