Blending Ultra-Deep Reservoir Mapping and High-Resolution Imaging for Precise Navigation and Optimal Completion Efficiency in Unconventional Jurassic Carbonates

This study aimed to enhance well-placement accuracy and optimize completion design in a tight Jurassic carbonate formation characterized by complex geological features, including dip-angle uncertainty, seismic resolution limitations, and lateral heterogeneity within the newly developed Liyah field. The objective was to improve reservoir contact and maximize production efficiency by integrating ultra-deep resistivity mapping and high-resolution imaging. A pre-well model incorporating offset-well data and seismic surveys was developed to predict tool responses and evaluate well-placement feasibility. An ultra-deep resistivity mapping tool provided real-time stratigraphic visualization, to aid wellbore placement. High-resolution ultrasonic imaging validated formation properties and identified natural fractures. Real-time inversion techniques enabled dynamic well-trajectory adjustments based on resistivity and structural mapping, optimizing reservoir contact. This integrated approach enhanced drilling accuracy, reduced geological uncertainty, and improved overall well-placement efficiency. During the lateral section, ultra-deep resistivity mapping identified a high-resistivity zone (U4, 250 Ω∙m, 6 ft thick). Real-time data analysis prompted a transition into the U3 zone (4 ft thick), ensuring optimal wellbore placement within the most productive interval. The 1D inversion data effectively mapped formation boundaries and dip variations and identified fractured zones, while 3D mapping assisted in evaluating fluid connectivity. Moreover, the high-resolution ultrasonic imaging further validated the presence of natural fractures. A total of about 700 fractures were detected over 1,700 ft of the lateral section, with some apertures of 1-2 ft. These fractures closely correlated with wellbore events such as losses and kicks, providing crucial insights into reservoir behavior. Based on the fracture distribution, the completion strategy was revised from multi-stage fracturing to a cemented perforated liner, significantly reducing costs by eliminating the need for complex hydraulic fracturing operations. This strategic shift not only saved two rig days but also lowered completion expenses, enhancing the overall economic viability of field development while maintaining production efficiency. The integration of advanced reservoir mapping tools provided unprecedented subsurface insights, improving steering decisions, fracture identification, and completion efficiency for the first time in the Liyah field. These findings contribute to the optimization of drilling and completion strategies in unconventional carbonate reservoirs, enhancing production outcomes and reducing development costs.