U.S. Geological Survey
U.S. GEOLOGICAL SURVEY BULLETIN 2016
Selected Papers in the Applied Computer Sciences 1992


CHAPTER A

Integration of Geographic Information Systems and Expert Systems Technology for Resource Management

By Betty M. Miller


CONTENTS

Abstract
Introduction
Program Objectives
Geographic Information Systems
The Role of GIS in Basin Analysis
GIS Pilot Study for the San Juan Basin
Expert Systems
The Role of Expert Systems in Basin Analysis
Knowledge-Based Expert System for the San Juan Basin
Integration of GIS and Expert Systems Technologies for Resource Management
Conclusions
References Cited

FIGURE

  1. A diagrammatic representation of an integrated GIS linking related surface and subsurface information crucial for evaluating, assessing, and managing natural resource programs (321kb)

Abstract

The U.S. Geological Survey is investigating the feasibility of applying geographic information systems (GIS) and expert systems technology to the development of a prototype resource information system. This information system will address the basic geologic issues of analyzing the Nation's sedimentary basins for the purpose of assessing their energy resources. The primary objective of this GIS/basin analysis project is to design a prototype information system that captures both the logic used to define the geologic concepts and the reasoning that enables the geologist to understand and reconstruct the evolution of a sedimentary basin. This system is designed to analyze the traditional concepts of source, reservoir, and trapping mechanisms; to help diagnose geological conditions favorable for the occurrence of petroleum or other energy resources; and to assess these resources. Appraisal methods can be directed to the resources in the entire basin or to limited areas, such as an exploration play or Federal and other land tracts.

This paper is a progress report that briefly summarizes the concepts and procedures being implemented for basin analysis to develop an integrated GIS and expert system to aid in assessing energy resources. This knowledge-based system will include information that would allow policy makers to deal more efficiently with energy and mineral exploration and development issues at regional, State, and national levels.

INTRODUCTION

Most of the world's energy resources and many of its metallic and mineral resources are derived from sedimentary rocks. The exploration and assessment of these resources require an understanding of their relation to the host strata within sedimentary basins, whether they are primary deposits or those formed after sedimentation. The most important result from the study of these host strata is a basin analysis that documents the geologic and paleogeographic evolution of a sedimentary basin and its related resource occurrences (Miall, 1984). The analysis includes many components, the most important of which are stratigraphy, sedimentology, and structural geology. Such a comprehensive basin analysis requires an understanding of data from many diverse specialists, including sedimentologists, stratigraphers, geophysicists, structural geologists, and geochemists, and the ability to assess the interrelations of many types of multivariate spatial data.

The concepts and methods for conducting sedimentary basin analysis have evolved from fairly simplistic geological studies that employed primarily qualitative and semiquantitative techniques to studies of ever- increasing complexity that employ quantitative evaluations from total basin systems. Complex quantitative methods require enormous amounts of diverse and multivariate spatial data necessary to quantify the geological, geophysical, geochemical, and hydrologic processes reacting during the history of a sedimentary basin.

Such an integrated analysis for a sedimentary basin is a difficult task to accomplish without computer assistance. It requires a multidisciplinary approach that draws on many areas of geologic expertise supported by the integration and analysis of large volumes of multivariate spatial data. This extensive data base requires the use of a computer to analyze effectively the data within the three-dimensional framework of a basin. However, new applications of knowledge-based computer mapping techniques, known as geographic information systems (GIS), and computer diagnostic programs, known as expert systems, may provide the tools needed to define strategies and technologies for conducting the complex tasks common to sedimentary basin analysis. These techniques, when applied to basin analysis, may be particularly useful for conducting energy and mineral resource assessments.

PROGRAM OBJECTIVES

One of the goals of the U.S. Geological Survey (USGS) is to develop GIS and related computer capabilities or the Survey's traditional geologic missions. These capabilities would permit rapid retrieval, display, and analysis of energy and mineral resource information on Federal lands throughout the United States. In response to the anticipated needs for resource management at the national policy-making level, the application of GIS technology within the USGS was proposed to address such questions as whether energy and mineral resources critical to national interests are available on federally owned lands.

The USGS is currently exploring the feasibility of applying GIS and expert systems technologies to a prototype system that provides the framework for analyzing sedimentary basins primarily to assess their energy and mineral resources. This paper, in the nature of a progress report, briefly summarizes the concepts and procedures being implemented in basin analysis to develop an integrated GIS and expert system to help assess energy resources. This knowledge-based system will include information that allows resource managers to deal more efficiently with issues related to energy and mineral exploration and development at regional, State, and national levels.

GEOGRAPHIC INFORMATION SYSTEMS

One definition of GIS is "a computer based technology composed of hardware, software, and data used to capture, edit, display, and, most importantly, analyze geographic information***. The key distinction between mapping software and GIS software lies in its ability to analyze spatial data" (Lang, 1989, p. 17). According to Dangermond (1989, p. 25), "A GIS is, first of all, an automated information system. A GIS brings information together, it unifies and integrates that information. It makes available information to which no one had access before, and places old information in a new context. It often brings together information which either was not or could not be brought together previously."

GIS were originally designed and developed nearly 20 years ago as a method to overlay and combine diverse kinds of data into a single map to summarize geographic, cultural, and scientific attributes. Since that time, these systems have evolved to serve many diverse applications, such as inventory mapping of forests, water, and other natural resources; lease management; topographic mapping; exploration; marketing and facility information; municipality planning; land-use planning; military applications; teaching; and scientific research. With the growing interest in three-dimensional geologic modeling and the importance of subsurface geologic analysis, new applications of GIS are currently being investigated. These GIS provide data integration to link surface and subsurface geology with associated rock attributes, such as those from geochemical and geophysical data (Loudon, 1986; Bak and Mill, 1989). A GIS typically links different data sets. Figure 1 illustrates in a spatial context the linking of related surface and subsurface data bases that can be represented as a number of data layers, or map coverages, useful to the assessment of natural resources. Present-day GIS data models can analyze geographic (and geologic) data and provide users with the ability to view and to analyze data relationships as well as to map, query, and manipulate spatial information (Chrisman, 1987).

GIS technology allows the integration of mapping and data-base functions that enable the user to integrate and manipulate spatial (coordinate) data with attribute (thematic) data to combine complex geographic, geologic, and geophysical data bases into resultant overlay and composite maps. It also permits the user to conduct multivariate spatial data analysis and to have access to a variety of options for analyzing these data bases.

The Role of GIS in Basin Analysis

Early GIS applications involved the mapping of essentially two-dimensional land-surface characteristics, such as land use, land ownership, and hydrographic, vegetation, and soil features. Most commercially available GIS products, however, cannot handle true three-dimensional data, although they can handle two- dimensional topographic data, usually as a digital elevation model (DEM), and display isometric and perspective views, contour maps, and so on. Some geological applications can be made by reducing the three-dimensional representation to a quasi three-dimensional one through the use of individual surfaces, or stacked subsurface layers. These surfaces, which can represent bedding planes or formation boundaries for potential or productive resource strata, can be contoured or displayed as isometric and perspective views.

The demands for detailed three-dimensional subsurface data are especially crucial in such applications as petroleum reservoir characterization (Jones, 1988), ground- water contamination modeling, ore-body delineation, and geotechnical site characterization for complex construction projects. The same needs and demands are also recognized for the characterization of three-dimensional subsurface data to (1) conduct studies on sedimentary basin evolution and (2) evaluate potential energy and mineral resources.

GIS Pilot Study for the San Juan Basin

The San Juan Basin, located in northwestern New Mexico and southwestern Colorado, was chosen for the IS pilot study primarily because it contains major economic deposits of natural gas, oil, coal, and uranium. The basin was a prime candidate for a study in the applications of GIS techniques to evaluate its energy resources. The San Juan Basin has been moderately to well explored and has over an 80-year history of development with more than 26,000 wells drilled in the area. The abundant well data and the results of many studies conducted in this basin by industry, government, and academic geologists provided the major sources of information, derived from raw and interpreted data, for building the basin data base.

Some of the major information sources used to develop the surface and subsurface cartographic data bases for the San Juan Basin are listed below. The U.S. GeoData System from the USGS's National Mapping Program is one of the cartographic data bases used for surface mapping in the investigation of this basin. It includes the Digital Cartographic Data Base (DCDB), which contains the digital elevation models (DEM) for terrain elevations and the digital line graphs (DLG) for planimetric information on boundaries, transportation, and hydrography. Other cartographic data bases used in the study are the U.S. Public Land Survey System, land-ownership data from the Bureau of Land Management (BLM), and land use and land cover (LULC) data. Additional data bases incorporated for use in the GIS for surface coverages include those concerning surficial geology, locations of oil and gas wells, well status, and oil and gas fields. Data bases created for subsurface mapping include structure contour, isopach, and facies information for the major oil- and gas-producing formations; stratigraphic information for cross sections, fence diagrams, and paleogeographic reconstructions; and various composited map products. The Petroleum Information-Well History Control System (PI-WHCS) data base (Petroleum Information, 1990) provided the major source for well information, depth and thickness information for identified formations within the basin, and a variety of data on productive reservoirs.

GIS technology applied in the San Juan Basin study was initially directed to the development and integration of the multivariate spatial data base needed for the analysis of these large volumes of surface and subsurface data. This technology, when applied to sedimentary basins, is used to establish a three- dimensional perspective of the basin's fundamental geologic, stratigraphic, and structural framework on the basis of subsurface data. Surface data are also used for information pertinent to the project, such as land ownership, surficial geology, topography, hydrography, and location of oil and gas wells (Miller, 1988, 1989b, 1992; Miller and others, 1990a,b).

GIS, featuring the integration of mapping and data-base functions, allow the geologist to generate maps and to apply a variety of options for analyzing and manipulating geographic and geologic information. Subsurface data coverages, representing geological surfaces and attributes, are used by the GIS as a part of the geographically referenced data base. The GIS, through its ability to carry out spatial operations, typically links the related surface and subsurface data sets by using the geographic locations (x and y coordinates) as the common key. The major advantage of using a GIS is that it allows the geologist to identify the spatial relationships existing between surface and subsurface features. Thus, complex spatial operations are possible with a GIS that would be difficult, time consuming, or impracticable otherwise.

Current GIS technology and mapping software being used by the USGS in this pilot study for the three- dimensional analysis of the San Juan Basin include ESRI's ARC/INFO GIS software (Environmental Systems Research Institute, 1987, 1990) and the Interactive Surface Modeling (ISM) mapping software package (Dynamic Graphics, 1984). Both software systems are run on the PRIME computer in Reston, Va.

EXPERT SYSTEMS

Research in applied artificial intelligence (AI) has achieved considerable success in developing powerful computer systems known as expert systems or knowledge-based systems. Research in expert systems concentrates on high- performance hardware and software that use symbolic programming to replicate knowledge, reasoning, and linguistic skills of people in specialized professions. These expert-systems programs are designed to represent and apply knowledge, rules, and judgments drawn from experts to solve problems by logical rules of inference rather than by calculations alone as in conventional, algorithmic programming.

Earth-science applications for expert systems include diagnosing drilling problems and problems with producing oil wells, interpreting and correlating well data, enhancing oil-recovery techniques, acquiring seismic data, and making geophysical interpretations. Expert systems are also used as exploration tools in mineral prospecting, such as Stanford Research Institute's PROSPECTOR (Duda, 1980) and Schlumberger's DIPMETER ADVISOR system (Baker, 1984). Some applications of expert systems in the USGS include use of the muPETROL program to classify sedimentary basins for petroleum-resource assessment (Miller, 1986, 1987a,b) and use of a microversion of PROSPECTOR for mineral exploration (McCammon and others, 1984; McCammon, 1986).

The capability of expert systems to deal with reasoning under uncertainty is essential to the geologist for various applications in the earth sciences. Assessing undiscovered energy and mineral resources within sedimentary basins is a prime example of reasoning under uncertainty. Typically, geologists deal with information that is usually incomplete, inferred or interpretive in nature, often uncertain, and sometimes unreliable. Frequently, the geologist must extrapolate from the known to the unknown when working in frontier areas for which there is little or no information.

The Role of Expert Systems in Basin Analysis

Some of the basic earth-science problems pertaining to energy and mineral resource issues are likely candidates for the application of knowledge-based expert systems. In addition to factual information, experts (geologists in this case) rely on their judgment, experience, and intuition in developing the chains of reasoning used in the decision- making process for assessing natural resources. This knowledge base is generally the result of many years of experience, usually accumulated at considerable cost over time. The many permanent products resulting from this expertise (such as records, files, papers, reports, logs, and maps) cannot be readily updated or sifted to solve a specific geologic problem or to determine the reasoning process that an expert may have used in resolving that problem in the past. Documentation of the interpretative reasoning that contributed to the decision-making process in earlier studies is often no longer available or never was recorded. It is the products of these experts, their data bases and reasoning processes, that are the prime sources of information for a knowledge-based expert system to be used in the diagnostic process of analyzing sedimentary basins.

It is important to the long-term strategic planning of energy and mineral resource projects to compile and document knowledge-based systems for sedimentary basins that are permanent and have continuity. Each basin system can be used as an ongoing decision-making tool by the team of experts building it as they encode and document their expertise as a reference for those who may need it in the future. Thus, expert systems provide a knowledge base that can be continuously updated and is amenable to changing geologic interpretations and exploratory conditions within the basins. Such a knowledge-based expert system can also provide for in-house training of new staff.

Knowledge-based expert systems can be used to document USGS expertise on all of the significant basins or energy and mineral provinces of the United States. Such systems could incorporate new concepts in basin analysis, along with the application of old and new methods for resource appraisal methodology.

The USGS is investigating the feasibility of using expert systems and knowledge acquisition techniques in two areas of sedimentary basin analysis: the design and construction of a global system for classifying sedimentary basins, as discussed by Miller (1986, 1987a,b, 1989a), and geological analysis of sedimentary basins to assess their petroleum potential.

The primary objective in this basin analysis project is to design a prototype expert system and knowledge- based GIS that captures both the logic used to define geologic basin concepts and the reasoning that enables the geologist to understand and reconstruct the geologic evolution of a sedimentary basin (Miller, 1986, 1987a,b, 1989a). Such a system can provide these capabilities through documentation of major basin analysis components such as stratigraphy, structural geology, and sedimentology. The system is being designed to analyze the traditional concepts of source, reservoir, and trapping mechanisms; to help in the diagnosis of geological conditions favorable for the occurrence of petroleum or other energy resources; and to assess these resources.

Knowledge-Based Expert System for the San Juan Basin

Work is currently in progress on the design and structure of a knowledge-based expert system for basin analysis in which the San Juan Basin is used for the pilot study. The long-term objective is the design of an integrated expert system that incorporates a knowledge-based GIS for the basin, along with the geologic data bases, that can provide the basin analyses crucial for resource assessment.

Findings from this study are critical to the long-term objective. For example, information from the pilot study can be used as input for the selection of energy-resource appraisal methods. These methods are used to calculate the remaining undiscovered energy resources in the basin, or to limited areas, such as an exploration play or tracts relevant to land ownership.

Such a procedure gives the user insight into the tasks needed to perform the following: (1) analysis of a sedimentary basin geologically by incorporating all known and analogous basin information; (2) interpretation and relation of these basin characteristics to the genetic occurrence and location of energy resources; and (3) development, selection, and application of the most credible resource appraisal methods for estimating the energy resources of a basin. The system would also provide for complete documentation of the information used (including any maps derived by GIS), the geologic assumptions made, and the methods applied for any particular assessment.

INTEGRATION OF GIS AND EXPERT SYSTEMS TECHNOLOGIES FOR RESOURCE MANAGEMENT

The integration of GIS and an expert system to develop a national resource land information system (LIS) is technically feasible. However, the magnitude of the effort and interagency contributions essential to such an undertaking would be considerable.

The functional requirements of a national resource LIS would fall into three categories: (1) data-base development, management, and inventory; (2) spatial analysis; and (3) map and report generation.

Initially, most of the effort to establish and operate such a resource information system would be related to data-base and knowledge-base development (surface and subsurface data capture, transformation, and registration), management (map and attribute storage and retrieval), and inventory (area and volume estimations). Data-analysis tasks, such as basin analysis in which a rule-based expert system and spatial data analysis are used, would then be conducted in response to the questions posed to the data base. Finally, computer and digital displays would provide the geologist with the capability to evaluate the results of the analyses interactively and to produce hard-copy maps and reports documenting results for interpretive or planning purposes.

Preliminary work conducted to date on a knowledge- based GIS for the San Juan Basin provides the geologist with the capability to manipulate essential surface and subsurface data layers, to interpret the basic geology of the basin, and to locate known energy resources. Integrating these GIS capabilities with a knowledge-based expert system provides the geologist with an "intelligent" data- management system for processing and interpreting the spatial data relationships. This integration creates an efficient system for the geologist to rapidly explore and view spatial data bases and provides the methods and algorithms for exploratory data-analysis and resource-appraisal procedures. The expert system also provides the geologist with a diagnostic tool to interpret, analyze, and forecast the occurrence of additional energy resources on the basis of the basin's geologic history.

Several national projects have been initiated by various Federal agencies that involve the application of GIS techniques to land information systems. Sturdevant and Kleckner (1984) report on one such project for the development of the Federal Mineral Land Information System (FMLIS), a GIS that would permit rapid retrieval, display, and analysis of mineral information on Federal lands throughout the United States. A pilot project was conducted on the Medford, Ore., (1 degree by 2 degree) quadrangle, and mineral occurrence and potential data were taken from the Conterminous United States Mineral Assessment Program (CUSMAP) and the Mineral Resource Data System (MRDS). A national FMLIS, however, has not yet been completed (R.L. Kleckner, oral commun., 1990). Some of the difficulties are attributed to the fact that land- status data, complete mineral-assessment data by geologic tract locations and their associated attributes from CUSMAP, and mineral-deposit and occurrence data from MRDS were available to FMLIS for only a limited number of areas in the United States.

A second national project using GIS technology has been initiated to develop LIS support for the BLM's oil and gas program. An oil and gas data-base system that is currently being designed will coordinate, within the BLM's LIS architecture, with those being developed for the Automated Lands and Minerals Record System (ALMRS) and the Public Land Survey/Geographic Coordinate Data Base (PLS/GCDB). This oil and gas automated-resource data base (ARD), in conjunction with the ALMRS data base, will be utilized to support a majority of the automated requirements of BLM's oil and gas program (Gazewood, 1989).

All of these automated national resource land information systems (such as FMLIS, BLM's LIS, and the basin resource information system discussed in this paper) have merit, are needed, and are technically feasible. They can increase access to energy and mineral resource information and provide effective use of natural resources, better service to the public, and more efficient decision making to support better resource management on public lands. "Whether for the government or private enterprise, managing thousands of acres of resources is a natural GIS application" (Ballou and Varney, 1990, p. 25). However, these large, automated information systems require the development of major data bases to be effective, and this effectiveness can only be achieved with considerable effort and dedication to the task.

CONCLUSIONS

GIS technology, when integrated with an expert advisory system, provides tools for innovative research in geologic interpretation, for developing and updating information data bases, for advancing new concepts in basin analysis for resource assessment, and for advancing new resource-appraisal methodology. GIS and expert systems can provide documentation and preserve invaluable, complex, and very large knowledge bases that are essential to the evaluation of energy and mineral resources for more effective natural resource management on Federal lands in the future.

REFERENCES CITED

Bak, P.R.G., and Mill, A.J.B., 1989,
Three dimensional representation in a geoscientific resource management system for the minerals industry, in Raper, Jonathan, ed., Three dimensional applications in geographical information systems: London, Taylor and Francis, p. 155-182.

Baker, J.D., 1984,
DIPMETER ADVISOR-An expert log analysis system at Schlumberger, in Winston, P.H., and Prendergast, K.A., eds., The AI business-Commercial uses of artificial intelligence: Cambridge, Mass., The MIT Press, p. 51-56.

Ballou, M.C., and Varney, S.E., 1990,
Mapping the costs and benefits of GIS: Digital Review, v. 7, no. 45, p. 25-29.

Chrisman, N.R., 1987,
Fundamental principles of geographic information systems, in Chrisman, N.R., ed., Auto Carto 8 Proceedings, March 29-April 3, 1987, Baltimore, Md.: American Society for Photogrammetry and Remote Sensing and American Congress on Surveying and Mapping, Eighth International Symposium on Computer-Assisted Cartography, p. 32-41.

Dangermond, Jack, 1989,
The organizational impact of GIS technology: ARC News, Environmental Systems Research Institute, Summer Issue, p. 25-26.

Duda, R.O., 1980,
AI and decision making-The PROSPECTOR system for mineral exploration-Final report, SRI Project 8172: Menlo Park, Calif., Artificial Intelligence Center, SRI International, 120 p.

Dynamic Graphics, 1984,
ISM Interactive Surface Modeling Users Guide (version 6.90): Berkeley, Calif., Dynamic Graphics, Inc., 148 p.

Environmental Systems Research Institute, 1987,
ARC/INFO Users Guide: Redlands, Calif., Environmental Systems Research Institute, Inc., v. 1, 364 p.

-----1990,
Understanding GIS-The ARC/INFO method: Redlands, Calif., Environmental Systems Research Institute, Inc., 507 p.

Gazewood, J.R., 1989,
Strategic management plan overview for the development of a fluid minerals land information system, in Denver GeoTech '89, Geoscientific information systems applied to exploration and research: Denver, Colo., Denver GeoTech, Inc., p. 96-107.

Jones, T.A., 1988,
Modeling geology in three dimensions: GEOBYTE, v. 3, no. 1, p. 14-20.

Lang, Laura, 1989,
GISes explode on the PC market: MicroCAD News, v. 4, no. 1, January, p. 17-20.

Loudon, T.V., 1986,
Digital spatial models and geologic maps, in Blakemore, Michael, ed., Digital mapping and spatial information systems: Proceedings Auto Carto, London, September 14-19, 1986, International Cartographic Association, v. 2, p. 60-75.

McCammon, R.B., 1986,
The muPROSPECTOR Mineral Consultant System: U.S. Geological Survey Bulletin 1697, 35 p.

McCammon, R.B., Boudette, E.L., Cameron, C.C., Cox, L.J., and Moench, R.H., 1984,
An expert system for mineral resource assessment in the Sherbrooke-Lewiston 1 degree by 2 degree quadrangles, Maine, New Hampshire, and Vermont: U.S. Geological Survey Open-File Report 84-751, 37 p.

Miall, A.D., 1984,
Principles of sedimentary basin analysis: New York, Springer-Verlag, 490p.

Miller, B.M., 1986,
Building an expert system helps classify sedimentary basins and assess petroleum resources: GEOBYTE, v. 1, no. 2, p. 44-50, 83-84.

-----1987a,
The muPETROL expert system for classifying world sedimentary basins: U.S. Geological Survey Bulletin 1810, 87 p.

-----1987b,
Sedimentary basin models documented on computer diskettes for USGS Bulletin 1810 for the muPETROL expert system for classifying world sedimentary basins: U.S. Geological Survey Open-File Report 87-0404, 5 p., one 5 1/4-inch diskette, MS DOS formatted.

-----1988,
Application of geographic information systems technology to resource assessment within sedimentary basins, in GIS Symposium, Integrating technology and geoscience applications, Abstracts: Denver, Colo., National Academy of Sciences/National Research Council, p. 79-80.

-----1989a,
Sedimentary basin analysis using computer expert systems: Geotimes, v. 34, no. 9, p. 14-15.

-----1989b,
Applications of geographic information systems to exploration studies in the San Juan Basin, New Mexico, in Denver GeoTech '89, Geoscientific information systems applied to exploration and research: Denver, Colo., Denver GeoTech, Inc., p. 121-123.

-----1992,
Guide to the development and application of geographic information systems for sedimentary basin analysis- Case study for the San Juan Basin, New Mexico and Colorado: U.S. Geological Survey Bulletin 2025.

Miller, B.M., Latzke, P.C., and Schachte, B.R., 1990a,
Videocassette demonstrating the applications of geographic information systems techniques to basin characterization; Case study for the San Juan Basin, New Mexico: U.S. Geological Survey Open-File Report 90-0275A, 6 p. text.

-----1990b,
Videocassette demonstrating the applications of geographic information systems techniques to basin characterization; Case study for the San Juan Basin, New Mexico: U.S. Geological Survey Open-File Report 90-0275B, VHS videocassette tape, 20 minutes.

Petroleum Information, 1990,
Well History Control System (WHCS) manual-Specifications for forms, codes, and abbreviations, magnetic tape/punched card formats: Denver, Colo., Petroleum Information, Inc., 1000 p.

Sturdevant, J.A., and Kleckner, R.L., 1984,
Spatial analysis requirements for a Federal Mineral Land Information System (FMLIS), in Spatial information technologies for remote sensing today and tomorrow, Pecora IX Proceedings: Sioux Falls, S. Dak., The Institute of Electrical and Electronics Engineers, Inc., p. 68-173.


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