The Lower Silurian Medina Group is a deltaic sequence composed of interbedded sandstones, siltstones, and shales, and is the primary target for natural gas in western New York. Chautauqua is the westernmost county in the state, and the most actively drilled for Medina gas. While the Medina Group underlies all of the county and is generally considered productive of natural gas, there is a wide disparity in the production results that cannot be attributed to structural control.
A sufficient number of wells have been drilled to allow comparison of production history and reservoir quality as determined from geophysical logs. Contouring of these data shows a preferential accumulation of natural gas along linear trends that correspond to zones of enhanced reservoir quality. These trends may have a primary origin related to deposition within a complex deltaic sequence or a secondary origin of diagenetic or tectonic nature. The apparent presence of definable productive trends in the Medina suggests their extension into undeveloped areas, where they would constitute a viable exploration objective.
