ABSTRACT

The study of topography to determine geology and geologic events is one of the basic principles of geomorphology. Recent advances in PC technology have allowed for an in depth study of the surface topography of Ohio on a macro scale. Surface features and interpreted lineaments are correlated with detailed subsurface maps. Topographic lows are interpreted to have developed along zones of preexisting weaknesses in the form of joints, faults, fractures, or some structural component. Topographic highs have sometimes been interpreted to develop as a result of actual structural uplift. Surface topography can, in many cases, be shown to correlate to actual basement structure.

These zones of weakness, or fracture zones, can be correlated to known productive oil and gas fields in eastern Ohio and are interpreted to be major routes of migration for hydrocarbons. Migration occurs both vertically and horizontally along fracture zones, which allows for updip migration. Vertical migration along fracture zones can account for downsection migration of hydrocarbons.

There are at least four major fracture zones that are interpreted to allow for migration from deeper in the Appalachian Basin in Pennsylvania and West Virginia. An additional fracture zone is interpreted to account for the migration of high nitrogen gas from the Kentucky portion of the Appalachian Basin. Migration patterns updip are believed to be controlled by an assortment of fracture zones, hinge lines, and structural arches, most of which are basement related.

Direct correlation of surface topography and migration routes to productive Ordovician/Cambrian oil and gas fields is demonstrated. Analysis of surface topography is shown to be a useful tool in exploration methodology.