The preservation of geological knowledge in a standardized digital form presents a challenge. Geological data in themselves are fuzzy. Data sources range in scale from the macroscopic, e.g., outcrop, through the mesoscopic, e.g., hand-specimen, core and sidewall core, to the microscopic, e.g., drill cuttings, thin sections, and microfossils. Each scale change results in increased heterogeneity and potentially contradictory data. Finally, the providers of such data may vary dramatically in experience level. Hence the challenge!
To address these issues, a geological description workstation has been developed for cores and drill cuttings, and has undergone field trials. Over two thousand carefully defined geological attributes are currently available within a relational database. Attributes are stored in definitive digital form, allowing multiple users to select familiar usage, e.g., diabase v. dolerite. Data can be entered in one language and retrieved in other languages. The data structure allows groupings of similar elements, e.g., rhyolites into the acidic-igneous or volcanics subgroups, or into the igneous rock group, permitting different users to analyse details appropriate to the scale of the application.
Data entry utilizes a graphical user interface, allowing the geologist to make quick, logical selections, in a standardized or custom-built format. Extensive menus, onscreen graphics and help screens allow "point-and- click" selection. Descriptive ranges, e.g., round to subrounded, are permissible. Error checking limits the potential for geological oxymorons. Entries for lithology, petrology, structures (sedimentary, organic and deformational), reservoir characteristics (porosity and hydrocarbon shows) and macrofossils are available. As data are selected and applied, the on-screen concatenated description is updated to provide immediate feedback, ensuring data correctness. Sampling points for thin-sections, core analysis, geochemistry or micropaleontology are also recorded.
Utilizing digital data storage, construction of geological logs using graphical, alpha-numeric (both abbreviated and complete words) and symbolic representations are possible. Geological descriptive data can also be combined with drilling and mud gas data, MWD and wireline logging data, and off-site analyses, to produce composite formation evaluation logs, thus enhancing the value of each data source through integrated information management.