THE TRENTON-BLACK RIVER PLAY -- AN HISTORICAL PERSPECTIVE

The presence of natural gas seeps around Findlay, Ohio, led to shallow drilling and excavations of the seeps in the early 1800s. The actual discovery of the Trenton and Black River (Ordovician) reservoirs of the Lima-Indiana trend occurred at Findlay in 1884, confirming that a gas deposit lay beneath the numerous seeps. The resulting boom led to wells being drilled virtually atop one another until dry holes were encountered. Early geologic studies of the time by Orton in Ohio and Phinney in Indiana recognized the general structural control of the Findlay Arch on the accumulation and the presence of porous dolomite as the reservoir, but this knowledge had virtually no bearing on reservoir development. Similarly, tar seeps in southwestern Ontario prompted shallow drilling starting in the 1860s, which led to the first confirmed subcommercial Ordovician production in 1900, and the first commercial field at Dover in 1917. The degree of geologic contribution to this Ontario exploration is unclear, but was probably limited; however, the characteristics of Dover Field, a syncline with a linear pattern of dolomitization, proved to be a model for later discoveries in Michigan and New York.

Two small linear Ordovician fields in southeastern Michigan, Deerfield and Northville, were discovered in 1936 and 1954, respectively, but the next significant Ordovician discovery was the Albion-Scipio trend in southern Michigan. The Ordovician reservoir at north end of the Albion-Scipio trend was actually drilled in 1943, but the well was plugged back to the Devonian. The impetus for drilling the discovery well, completed in early 1957, was due to a vision by a practicing psychic, not geology.

The combination of long periods without success interspersed with a few spectacular discoveries have continued to feed explorationists’ dreams of finding more Trenton-Black River reservoirs. The last 20 years of successes in southwestern Ontario and the most recent events in New York and West Virginia have shown that, for once, geology has an important role in this exploration. An understanding of regional tectonics to predict probable basement-related fault and fracture zones coupled with modern geophysical methods has proven an effective exploration strategy; however, finding these reservoirs still remains elusive and unpredictable.