Laura S. Mastella

PetroGrapher: managing petrographic data and knowledge using an intelligent database application

This paper describes the PetroGrapher system, an intelligent database application to support petrographic analysis, interpretation of oil reservoir rocks, and management of relevant data using resources from both knowledge-based system technology and database technology. In this project, the visual tacit knowledge applied in petrographic analysis was rendered explicit through the collection of cases (rock descriptions), which were then used in the development of a domain ontology organized in a partonomy. Expert-level basic features, which we call ‘visual chunks’, were identified. The cases were further compared against the ontology to elucidate the relations between features in descriptions of rocks, visual chunks and expert interpretations. The domain knowledge was represented through a set of frames and knowledge graphs. The knowledge graphs are applied to recognize the visual chunks in the user data and retrieved the related interpretation. The system was developed as a structure tightly coupled with a relational database system, which acts as a repository for the knowledge base and the user data, and an object-oriented component, which preserves the semantics of data and develops inferences. The system was validated by three groups of users with different levels of expertise. q 2003 Elsevier Ltd. All rights reserved.

How to Model Visual Knowledge: A Study of Expertise in Oil-Reservoir Evaluation

This work presents a study of the nature of expertise in geology, which demands visual recognition methods to describe and interpret petroleum reservoir rocks. In an experiment using rock ima ges we noted and analyzed how geologists with distinct levels of expertise described them. The study demonstrated that experts develop a wide variety of representations and hierarchies, which differ from those found in the domain literature. They also reta in a large number of symbolic abstractions for images. These abstractions (which we call visual chunks) play an important role in guiding the inference process and integrating collections of tacit knowledge of the geological experts. We infer from our experience that the knowledge acquisition process in this domain should consider that inference and domain objects are parts of distinct ontologies. A special representation formalism, kgraphs+, is proposed as a tool to model the objects that support the infer ence and how they are related to the domain ontology.

Event Ordering Reasoning Ontology Applied to Petrology and Geological Modelling

The inference of temporal information from past event occurrences is relevant in several applications for geological domains. In such applications, the order in which events have happened is imprinted in the domain as visual-spatial relations among its elements. The interpretation of the relative ordering in which events have occurred is essential for understanding the geological evolution in different scales of observation and for various kinds of objects, as in Petrology and Geological Modelling. From the analysis of the cognitive abilities of experts in these domains we propose an ontology for event ordering reasoning within domains whose elements have been modified by past events. We show that the Event Ontology can work as a pattern for domain conceptualization to be applied in distinct domains. It can be used to specify the sequence order of diagenetic paragenesis. It can also be operative for automatic reconstruction of geological surface assemblages.

Formalizing Geological Knowledge through Ontologies and Semantic Annotation

The paper addresses the problem of integrating various applications related to geological interpretation within an integrated workflow. This supposes the exchange of different types of objects related to several knowledge fields (seismic, stratigraphy, structural geology), represented in various formats. The solution that we propose consists in linking specialized ontologies describing the different fields knowledge to a pivot ontology related to basic geological knowledge. The linkage between these ontologies and the earth modelling applications can be operated thanks to the semantic annotation technology. The paper presents some key-elements of this pivot ontology and gives an outline of the semantic annotation methodology, studied as a possible solution for modelling workflow integration.