Beyond Palynology: Real-Time Reservoir Characterization in Bolivia’s Devonian HPHT Plays

Summary In Bolivia’s structurally complex Sub-Andean region, traditional stratigraphic techniques—such as palynology and wireline logs—often fail to provide timely or reliable data during drilling of deeply buried Devonian formations. This study introduces an innovative surface-based workflow using Advanced Cuttings Characterization (ACC) to overcome challenges posed by downhole motors, which pulverize rock and hinder visual lithological descriptions. Applied in real time for the first time in Bolivia, ACC enabled accurate identification of formation tops and reservoir transitions within the Huamampampa Formation, hosted in duplex fault systems and subject to HPHT (High Pressure High Temperature) conditions. The methodology integrates DRIFTS (Diffuse Reflectance Infrared Fourier Transform Spectroscopy) to characterize mineral assemblages such as quartz, feldspars, chlorite, and illite, while X-Ray Fluorescence (XRF) provided elemental ratios (e.g., Zr/SiO2, SiO2/Al2O3) to enhance Iithofacies discrimination. Organic content was evaluated through TOC estimates, and gamma ray proxies were calculated directly from cuttings, allowing continuous correlation with subsurface data. This integrated approach proved critical for real-time geological decision-making. It demonstrated that cuttings-based mineralogical and geochemical analysis can replace or complement delayed downhole methods, de-risking operations and refining stratigraphic models in geologically demanding HPHT basins.