A New Sequence Stratigraphic Model for the Niagara-Lower Salina Reef Complex of the Guelph Formation, Michigan Basin, USA

Abstract

Hydrocarbon reservoirs in the Niagara-Lower Salina Reef Complex in the Michigan Basin have been extensively studied since the early 1960's. These reservoirs host an immense hydrocarbon resource, existing as closely-spaced, highly-compartmentalized reservoirs that have produced >500 million barrels of oil and 2.9 trillion cubic feet of natural gas. Previous studies depict these “pinnacle reefs” as tall, symmetrical towers with a random distribution of facies. This study utilizes abundant core data (32 cores, 20-acre spacing), thin-section petrography, and petrophysical wireline logs to reconstruct the geometry, facies distributions, depositional history, and sequence stratigraphy of the Columbus III Reef Complex within the Southern Niagaran-Lower Salina Reef Trend. Our analysis indicates that there are three depositional sequences, which include a lower bioherm complex, the middle Niagaran reef complex, and the uppermost Lower Salina A-1 Carbonate. These sequences are highly influenced by relative sea level fluctuations within the MI Basin, and can be correlated to global seal level changes. The bioherm complex is relatively homogenous, and acts as a topographic high upon which the reef complex nucleates. Within the Niagaran reef sequence there are five major depositional facies, each with their own characteristic shallowing upward trend. These facies include: reef core, reef talus, proximal reef apron, distal reef apron, and flank. The overall geometry of the reef complex and the vertical and horizontal facies distributions within the reef are highly asymmetrical, and are dominated by a northeast paleo-wind direction. Lateral facies distributions in the Lower Salina A-1 Carbonate are highly influenced by the underlying topography set up by the Niagaran reef sequence. This new stratigraphic model allows for better predictability within the MI Basin, particularly in reefs without abundant well control. The high-resolution model also permits more accurate correlations between the Lower Salina shallow-water carbonate factory and the surrounding inter-reef and basin center carbonates, which represents a potential unconventional resource.

AAPG Datapages/Search and Discovery Article #90259 ©2016 AAPG Annual Convention and Exhibition, Calgary, Alberta, Canada, June 19-22, 2016