Scholarlink

<p>The Lower Cretaceous Amrha Sandstone Member is a key hydrocarbon reservoir in the eastern Sirte Basin, Libya. Despite the unit's considerable economic importance, high-resolution sedimentological and petrological studies remain scarce, particularly those that investigate their impact on reservoir development and quality. Therefore, this study examines core samples and thin sections to analyze the sedimentary and depositional characteristics of the Amrha Sandstone Member, identifying factors that impact reservoir quality. Petrographic analysis indicates that the Amrha Member consists of seven lithofacies: quartz arenite, sublithic arenite, lithic arenite, lithic wacke, subfeldspathic arenite, quartz wacke, and silty claystone. Diagenetic processes in the Amrha Sandstone Member are characterized by widespread quartz overgrowths, particularly in quartz arenites, which commonly reduce intergranular porosity and create interlocking grain textures. Kaolinite is present in multiple forms, including pore-filling, grain-replacement, and grain-coating, accompanied by minor amounts of other clays, pyrite, and chlorite. Core analysis from multiple drill sites reveals diverse sedimentary structures, including current ripples, parallel laminations, tabular and trough cross-bedding, reactivation surfaces, and clay clasts with pebbles. Based on lithofacies and sedimentary structures, three depositional complexes are interpreted: fluvio-deltaic, coastal plain and shoreline, and braided fluvial complexes. The fluvio-deltaic complex comprises distributary channels, crevasse bays, and mudflat-bay facies. The coastal plain and shoreline system includes tidal flats and tidal sandbars, while the braided fluvial system features braided bars, braided channels, and abandoned braided channels. Reservoir quality is mainly determined by sedimentation processes, with the most favorable facies for high-quality reservoirs including braided bars, braided channels, and tidal sandbar deposits. This research introduces a conceptual framework that enhances oil and gas exploration and development of the Amrha Sandstone Member, a significant hydrocarbon reservoir in the eastern Sirte Basin. It also offers insights for predicting uncertainty in hydrocarbon exploration and development in comparable settings.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Depositional model for the Early Cretaceous Amrha Sandstone Member in the eastern Sirte Basin, Libya: Implications for reservoir quality

  • 期刊论文

  • 发表日期：

    2025年8月30日

查看全文
  • Muneer Abdalla,
  • Abdalla Abdelnabi,
  • Mohamed Saleh,
  • Husamaldeen Zubi,
  • Yousf Abushalah,
  • Saleh Qaysi

摘要

The Lower Cretaceous Amrha Sandstone Member is a key hydrocarbon reservoir in the eastern Sirte Basin, Libya. Despite the unit's considerable economic importance, high-resolution sedimentological and petrological studies remain scarce, particularly those that investigate their impact on reservoir development and quality. Therefore, this study examines core samples and thin sections to analyze the sedimentary and depositional characteristics of the Amrha Sandstone Member, identifying factors that impact reservoir quality. Petrographic analysis indicates that the Amrha Member consists of seven lithofacies: quartz arenite, sublithic arenite, lithic arenite, lithic wacke, subfeldspathic arenite, quartz wacke, and silty claystone. Diagenetic processes in the Amrha Sandstone Member are characterized by widespread quartz overgrowths, particularly in quartz arenites, which commonly reduce intergranular porosity and create interlocking grain textures. Kaolinite is present in multiple forms, including pore-filling, grain-replacement, and grain-coating, accompanied by minor amounts of other clays, pyrite, and chlorite. Core analysis from multiple drill sites reveals diverse sedimentary structures, including current ripples, parallel laminations, tabular and trough cross-bedding, reactivation surfaces, and clay clasts with pebbles. Based on lithofacies and sedimentary structures, three depositional complexes are interpreted: fluvio-deltaic, coastal plain and shoreline, and braided fluvial complexes. The fluvio-deltaic complex comprises distributary channels, crevasse bays, and mudflat-bay facies. The coastal plain and shoreline system includes tidal flats and tidal sandbars, while the braided fluvial system features braided bars, braided channels, and abandoned braided channels. Reservoir quality is mainly determined by sedimentation processes, with the most favorable facies for high-quality reservoirs including braided bars, braided channels, and tidal sandbar deposits. This research introduces a conceptual framework that enhances oil and gas exploration and development of the Amrha Sandstone Member, a significant hydrocarbon reservoir in the eastern Sirte Basin. It also offers insights for predicting uncertainty in hydrocarbon exploration and development in comparable settings.