A METHOD FOR LOCATING ABANDONED OIL WELLS IN WOOD COUNTY, OHIO USING REMOTE SENSING AND GEOPHYSICAL TECHNIQUES

The study site was in northwest Ohio; it was subjected to extensive oil production at the end of the 1800's. As a result, there is a high density of abandoned wells throughout the region, which can present a groundwater pollution hazard. Although some wells can be located by their casing protruding from the ground, many landowners have remove the casing making the well impossible to locate by inspection. The focus of this study was to develop and refine a rapid and low-cost method for the location of abandoned oil wells in northwest, Ohio using resistivity, magnetics, and a hand-held spectrometer. The resistivity, measured with a capacitively-coupled resistivity apparatus, was relatively low around the location of the well. Interpretation of resistivity contour maps generally yielded a likely location for the well within approximately 5m. Depth inversions show a relative low in resistivity almost directly under the pipe in all but 4 of the10 wells studied. The magnetic intensity contour maps showed a high within 2m of the known wells. The spectra of soil samples taken from each well site show a small absorption band near 2.2µm. Though this band was found at every site it is so small that this study found it impractical for locating wells. Overall, the most effective approach involves collection of magnetic data first, followed by electrical resistivity and inversion modeling over sites indicated as probable by the magnetic data.