Silurian Reef Systems in the Illinois and Michigan Basins - What can be learned from modern quarrying operations in North-Central Indiana

Abstract

The quarrying of dolomite and limestone material from the Silurian of North Central Indiana has been ongoing for over 100 years. These quarrying operations are located near the crest of the northwest to southeast trending Cincinnati Arch generally along river valleys where the amount of glacial overburden that needs to be removed prior to quarrying is minimal. These quarrying operations have created vertical outcrops that can be hundreds of feet in height and over a thousand feet length of Silurian carbonates. A significant number of these quarrying operations have cross-cut and exposed Silurian Reef complexes. These reef complexes range from 10's of feet to over 1000's feet in width and up to 100 feet in height.

Silurian reef complexes are very important oil and gas reservoirs in the Michigan and Illinois Basins. In the Michigan Basin, over a thousand reef complex oil and gas fields have been discovered since 1950's producing approximately 500 MMBO to date. While in the Illinois Basin, production from Silurian reef complexes was initiated in 1946 with over 130 MMBO having been produced to date from nearly a 100 reef complex reservoirs. Unfortunately, many of the Silurian reef reservoirs discovered in the 1950's through the 1980's are poorly documented by seismic, incomplete well penetrations of the reservoir interval, limited well logs and core material. Future enhanced, oil and gas recovery and exploration programs targeting Silurian Reef reservoirs will depend on a better understanding of these complex carbonate reservoir systems to be successful. Where can we get additional geological information on these complex carbonate systems? The exposed Silurian reef complexes and associated flank carbonate facies exposed in currently operating quarries in North Central Indiana can provide information on potential carbonate facies development, reservoir heterogeneity, geometry and potential fluid flow characteristics of Silurian reef complexes not available from existing Silurian reservoirs in the Illinois and Michigan Basins or natural outcrops. Let's take a virtual field trip of these man-made outcrops.

AAPG Datapages/Search and Discovery Article #90258 © 2016 AAPG Eastern Section Meeting, Lexington, Kentucky, September 25-27, 2016