Abstract: Geoplay: A Knowledge-Based Expert System for the Analysis of Potential Hydrocarbon Plays

Betty M. Miller

Research efforts by the U.S. Geological Survey (USGS) in techniques for sedimentary basin analysis are currently being directed toward the design and implementation of diagnostic expert systems and knowledge-based acquisition techniques for the analysis of potential hydrocarbon plays. This presentation describes a unique approach to the design and application of a rule-based expert system, called GEOPLAY, to the analysis of exploration plays, a methodology commonly used to assess petroleum resources in sedimentary basins.

GEOPLAY is a knowledge-based expert system designed by the author to diagnose the geologic characteristics essential to the identification and analysis of potential plays and their prospects. Work is in progress to adapt the geologic model used by the USGS in their play analysis procedures for GEOPLAY's knowledge base. The object is to capture the facts, logic, and reasoning used by geologists to characterize the play-analysis model and to evaluate the play. These expert-systems techniques are capable of dealing with inexact reasoning or reasoning under uncertainty by incorporating degrees of uncertainty to deal effectively with incomplete, inferred, or interpretive geologic data included in the knowledge base. The goal of this study is to provide a diagnostic expert-systems approach or characterizing geologic plays in order to expand upon the play-analysis system. The GEOPLAY expert system acts as a guide to navigate the geologist through the recognition, identification, and characterization of the geologic conditions used to define the play. It also provides the geologist with capabilities to document the major basin components such as stratigraphy, structural geology, and sedimentation, to evaluate the traditional concepts of source, reservoir, and trapping mechanisms. GEOPLAY assists the geologist in compiling and interpreting the geologic and reservoir engineering data necessary for running the probabilistic methods to calculate the amount of probable petroleum resources within each prospect for a particular play.

Diagnostic expert-systems technology, as demonstrated by the design and application of GEOPLAY, can provide challenging new tools in knowledge acquisition and data interpretation in petroleum geology.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994