Abstract: System For Regional Lithofacies Mapping by Computer

D. A. Clark

Mobil Oil Canada, Ltd., Lithology System services a lithologic data file containing data from more than 5,000 wells throughout Alberta, northeast British Columbia, and the Northwest Territories. The file is maintained and the retrieval logic defined by the MARK IV information-system facilities. The file consists mainly of digitized lithology data routinely supplied by the Canadian Stratigraphic Co., Ltd., but also provides for the inclusion of data coded by Mobil Oil geologists.

The format provides for the description of such rock characteristics as major rock type, framework, grain size, secondary rock type and qualifiers, rock builders, rounding and sorting, metasomatism, porosity grade and type, color, oil stain, fossils, and accessory minerals. The system allows a geologist to create a subfile of his data within a given area and interval of interest. The interval can be specified in terms of stratigraphic units, subsea elevations, drill depths, or a combination of these.

By means of a processing program based on MARK IV logic, the geologist can examine any individual rock characteristic or combination of characteristics to produce various mappable parameters such as net footages, percentages, center of gravity, and vertical range of deposit.

In addition, an interactive graphics program allows the geologist to preview his data by rapid display of small-scale maps of the preceding items enabling him to pre-select the more significant characteristics to be analyzed and mapped by the processing program.

AAPG Search and Discovery Article #90968©1977 AAPG-SEPM Annual Convention and Exhibition, Washington, DC