Stratigraphically Sound Use of Commercial Well History Data Bases for Geologic Mapping--Michigan Basin Case History

Philip H. Stark

Sound project planning and application of rock unit stratigraphic principles are essential to assure optimal use of commercial well history data bases for geologic mapping. Project planning should consider data base content, stratigraphy, and maps that are required to achieve project objectives. Stratigraphic audits that record the number of wells that report tops, production, tests, cores, and shows for each formation are a fundamental planning tool. Operator-reported formation-top nomenclature reflects local mappable rock units. With knowledge of regional stratigraphic relationships, the logic for appropriate retrieval algorithms and formation-top file structures can be established from the audits. In complex facies, such as reef trends, as many as five synonymous forma ions may be required to identify a single mappable unit. Formation-top files should accommodate the hierarchical selection of synonymous formations and their identification by an alphabetic code.

These principles are illustrated with an example from the Niagaran reef trend in Antrim and Kalkaska Counties, Michigan. In this example, 16 rock units were selected to map six formations from the Silurian A2 carbonate to the Clinton dolomite. Structure, isopach, trend, residual, and subcrop maps with shows and lithologic designations demonstrate the utility of sound planning and flexible formation-top file structures to generate successful geologic mapping results from commercial well files.

AAPG Search and Discovery Article #91022©1989 AAPG Annual Convention, April 23-26, 1989, San Antonio, Texas.