Lithologic Logs in the Tablet through Ontology-Based Facies Description*

The definition of sedimentary facies through the description of cores and outcrops provides the basis for the construction of calibrated reservoir models, assembled via the anchoring of 3D geological objects. The realism and accuracy of such models depends on systematic and substantial information about the lithologies, including detailed description of sedimentary structures and textures. The major obstacle for the systematic definition and representation of depositional facies, and mostly, for their processing within computer-generated reservoir models, resides in the lack of a formal nomenclature of sedimentary structures and of agreement about what each term means. An advanced computer application developed to support the detailed and systematic description of lithology, sedimentary structures and texture of cores and outcrops combines resources from knowledge systems and human-oriented interfaces. Systematic description is facilitated by the use of a visual, intuitive interface in touch-screen tablet devices, supported by standardized nomenclature and parameters. Depositional and post-depositional structures were associated to visual representations (icons) that emulate the way in which geologists usually represent graphic logs, with a touch-select-draw interface. The descriptive nomenclature was formally defined based on ontology engineering methods and validated by a group of sedimentologists using a web collaborative portal. The application substantially improves data quality and reduces description time, and allows capturing the information into a relational database for further processing and exportation to several standard formats, essential for the efficient construction of realistic reservoir models for optimized recovery and quality prediction.