Novel Three-Dimensional Integrated Approach for Distal and Near-Wellbore Reservoir Characterization

Optimizing hydrocarbon recovery in complex reservoirs requires a robust and precise reservoir characterization. This sometimes can be hindered by limitations in traditional single-measurement tools especially in reservoirs with complex architecture, which could impose challenges for optimal well placement due to variations in reservoir structure, formation dip, and rock quality. This paper discusses a novel three-dimensional (3D) holistic integration of electrical borehole imaging, far-field dipole sonic, and deep resistivity imaging in a directional wellbore drilled in a tight heterogenous carbonate formation. Borehole images enable the identification of reservoir rock properties and characterization of structural features that intersect the wellbore. Contrasts in electromagnetic resistivity measurements provide insights on fluid saturation and rock quality, whereas far-field sonic imaging offers details pertaining to distal reservoir layering and fracture extension. Using the strengths of each tool, this integrated approach provides comprehensive reservoir insights at and away from the wellbore. An automated 3D dipole sonic imaging workflow has been developed to detect and characterize arrival events in the filtered pre-migrated wavefield using a combination of tau-P event picking, ray tracing inversion, and 3D Slowness Time Coherence (STC) processing. The workflow results include 3D mapping of the reflectors along the well trajectory and their attributes such as true dip and azimuth. Quantitative comparison with borehole image logs helps assess lateral continuity of reservoir boundaries and identifies potential extension of fractures. A case study in a tight heterogenous carbonate reservoir is included herein to illustrate the novel approach effectiveness and business value. The results indicate that the wellbore crossed two different layers with distinct structural characteristics. The first layer is dominated by discontinuous conductive fractures with NE-SW strike orientation, whereas the second layer is more vuggy with fewer fractures. The deep shear imaging indicates that fractures have higher density in the first layer and extend up to 80 ft. away from the wellbore. These findings highlight the integrated approach benefits including reduced uncertainty and improved decision-making capabilities for optimized production operations.