3-D Interpretation of the Sequence Stratigraphy and Reservoir Property Distribution in the Belle River Mills Silurian (Niagaran) Reef, St. Clair County, MI

Heather Qualman¹, G. Michael Grammer¹, William Harrison III¹, and Matthew Pranter^2
1Western Michigan University, GeoScience Dept, Kalamazoo, MI, [email protected]
²University of Colorado, Department of Geological Sciences, Boulder, CO, [email protected]

Silurian (Niagaran) reefs are significant hydrocarbon reservoirs in the Michigan Basin, having produced nearly 470 MMBO and 2.75 trillion cubic feet of gas. The primary production for these reservoirs is generally low, averaging about 25%, due to their complex internal heterogeneities. Detailed facies analysis of 12 cores in the Belle River Mills (BRM) field indicate a correlation often exists between depositional facies and porosity/permeability values. Sequence stratigraphic analysis conducted on the cores revealed 3 fourth-order high frequency sequences, seen consistently in each of the 12 cores. Schlumberger’s Petrel modeling software was used to generate 3-D facies, porosity, and permeability models as a means of enhancing the understanding, and possible controlling mechanisms, of reservoir property distribution in the BRM reef. Variograms, cell sizes, layer geometry, and the number of layers within the model were independently tested to determine which set of parameters ultimately produced the most geologically reasonable model of the BRM reef reservoir. The model was then tested against core descriptions and sequence stratigraphic analysis performed by previous workers. It was determined that using at least 300 proportional layers and variograms with ranges of 500 feet produce models that realistically represent the distribution of facies and reservoir properties throughout the reef. Results reveal a geometrically well-developed windward margin at the southeastern edge of the reservoir, with porosity and permeability concentrations on the eastern margin of the reef, though permeability distribution is slightly more variable. An understanding of the sequence stratigraphic framework and the correlation between detailed facies and reservoir quality should enhance primary and secondary production in these reservoirs.

AAPG Search and Discovery Article #90095©2009 AAPG Eastern Section Meeting, Evansville, Indiana, September 20-22, 2009