What is it about?

This study focuses on establishing a detailed structural model for the Asmari reservoir, a task complicated by challenging crossings and the presence of an extensive layer of Gachsaran formation evaporates above the reservoir. To achieve this, the researchers utilized geological logs to classify dip angles, aiding in identifying fault and fracture systems within the Asmari formation. Investigation into the intersection of the Kalhur member and an unexpected thickness increase in the Asmari formation involved analyzing Formation MicroImager (FMI) data within a specific depth interval. The analysis of bedding dips revealed abrupt variations, crucial in understanding the reservoir's structural complexities. The study identified a significant reverse fault within zone five of the Kalhur member, evidenced by distinct dip patterns and log characteristics. This fault influenced elevated dips in the surrounding beds due to the plastic nature of anhydrite present in the formation. The analysis of anhydrite indicators from FMI and gamma-ray logs further supported the identification of the fault within this zone. Interpreting structural dip played a pivotal role in resolving complexities, allowing for precise positioning of the well within the Asmari reservoir. This accurate positioning enabled the well to access the lower contact of the Asmari formation. The interpretation was facilitated through detailed analysis of FMI images and petrophysical logs in a specific well, LL-26.

Featured Image

Why is it important?

This study holds significant importance for several reasons: Reservoir Accessibility: Understanding structural complexities in formations like the Asmari reservoir is crucial for successful access. The study addresses challenges related to crossing this reservoir, which is essential for effective oil and gas extraction. Optimized Exploration: By establishing a precise structural model, the research aids in optimizing exploration and extraction strategies. Understanding fault and fracture systems impacts production, and a comprehensive model enhances efficiency. Data Utilization: Utilizing geological logs for dip classification and interpreting FMI data are innovative approaches. These methods offer more direct insights into the structural origin, fault systems, and changes within the reservoir, providing a more accurate understanding. Identification of Faults: The identification of a significant reverse fault within the Kalhur member is pivotal. Understanding fault characteristics and their impact on nearby formations is essential for navigating these structures during drilling. Reservoir Characterization: The analysis of anhydrite and marly/shaly anhydrite within the formation provides insight into the reservoir's properties. Identifying these elements and their relationship to structural formations aids in characterizing the reservoir. Improved Drilling Accuracy: The precise determination of the well's location within the reservoir is critical. It enables drilling to reach the lower contact of the Asmari formation, enhancing accuracy and potentially improving resource extraction. Overall, this study's findings have significant implications for optimizing exploration strategies, understanding reservoir complexities, and improving drilling accuracy in challenging structural environments like the Asmari reservoir.


This study on the Asmari reservoir's structural modeling is valuable for several reasons: Navigating Structural Challenges: Dealing with complexities during the crossing of the Asmari reservoir, especially with the overlaying Gachsaran formation, is a significant challenge. Establishing a precise structural model is crucial for successful navigation in such scenarios. Methodological Innovations: Utilizing geological logs for dip classification and interpreting FMI data in this context are innovative methods. These approaches offer a more direct insight into fault systems and structural complexities, providing a comprehensive understanding of the reservoir. Identifying Fault Systems: The identification of a significant reverse fault within the Kalhur member is a notable outcome. Understanding fault characteristics and their implications on nearby formations is pivotal for drilling and reservoir characterization. Reservoir Characterization: Discovering the influence of anhydrite and marly/shaly anhydrite on the beds and layers contributes to understanding the reservoir's properties. This characterization aids in comprehending the reservoir's nature and behavior. Improved Well Placement: Precisely determining the well's location within the reservoir is critical. Accurate positioning allows the well to reach the lower contact of the Asmari formation, which enhances the potential for effective resource extraction. In conclusion, this study's findings and methodologies significantly contribute to understanding the structural complexities of the Asmari reservoir. It offers insights that can optimize drilling strategies, improve reservoir characterization, and enhance resource extraction in challenging geological environments.

Dr Zohreh Movahed

Read the Original

This page is a summary of: Analytical Fractured Reservoir Characterization by using Geological and Petrophysical Logs, Current Research in Geoscience, January 2022, Science Publications,
DOI: 10.3844/ajgsp.2022.11.28.
You can read the full text:



The following have contributed to this page