Depositional Facies of Middle Silurian (Niagaran) Pinnacle Reefs, Belle River Mills Gas Field, Michigan Basin, Southeastern Michigan

Abstract

Niagaran reefs have been the main source of oil and gas production in the state of Michigan for the past three decades. In 1980, the reefs produced about 28 million barrels of oil (82 percent of the state’s production) and almost 150 billion cubic feet of gas (94 percent of the state’s production). At the end of 1980, cumulative production from the reefs reached 190 million barrels of oil and 1.12 trillion cubic feet (31.8 billion m3) of gas (Bricker et al., 1982). Estimates of the primary recoverable reserves contained in the reefs range between 300 to 400 million barrels of oil and 3 to 5 trillion cubic feet (85–140 billion m3) of gas (Mantek, 1976; Caughlin et al., 1976; Yelling and Tek, 1976). The main purpose of this study is to present a detailed analysis of the petrography and sedimentary facies of one of the largest and best core-sampled Niagaran pinnacle reefs in the Michigan Basin, and evaluate their spatial disposition.