Stratigraphic Applications of Geologic Analysis System: ABSTRACT

Abstract

The Geologic Analysis System is a multipurpose data-management and applications software package designed to graphically integrate massive amounts of data to help solve oil and gas exploration and research problems. The Geologic Analysis System includes: (1) TECH/SYS, a technical file-management system that can accommodate multiple files, (2) PICS, a user-friendly geologic mapping and contouring system, and (3) applications programs, which retrieve, manipulate, list, and display a wide variety of rock sample analytical data. Benefits to the stratigrapher include: (1) publication- or report-ready graphic displays, (2) database edit routines, and (3) both graphically and statistically displayed outcrop sections and cores that objectively define the stratigraphic character of a rock sequence. The utility of the Geologic Analysis System is demonstrated by a case study involving the Lower Cretaceous (Albian) Blackleaf Formation in southwestern Montana. A TECH/SYS database was created for a composite stratigraphic section of the Blackleaf Formation near Lima. Analysis of the database reveals 4 Blackleaf lithofacies units: (1) lower transitional clastic unit, (2) lower shale unit, (3) upper clastic unit, and (4) upper volcaniclastic unit. To define lithofacies variation objectively, stratigraphically variant data items are graphically displayed and analyzed. These data items include textural elements, porosity, mineralogy, lithology, paleontology, paleocurrent direction, and diagenetic features. Where applicable, bivariate plots, ternary diagrams, and multivariate statistical outines, such as discriminant function analysis and cluster analysis, are used to define the lithofacies variation. End_of_Article - Last_Page 251------------