Although the response of a particular target may be predictable, the local background resistivity also determines detectability of the target. This summary discusses the changes in loop sizes as well as the changes in data processing that were necessary for buried borehole detection in different environments. Abstract It is sometimes difficult to determine in advance exactly which equipment or technique is best suited to a given project. Although the response of a particular target may be

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... table, the local background response may be more difficult to assess until field data have actually been gathered. This problem becomes economically significant when the job site is relatively remote, requiring downtime and/or additional airfreight expenses when the actual field results do not match expectations and a change in equipment systems becomes necessary. An example of this is a recent series of surveys in Indiana and Ohio, in which the goal was to ensure that no abandoned, buried oil wells were present within a prescribed radius of proposed injection wells. After local tests, both the physical survey layout and the data processing techniques were varied in order to detect the various possible targets in the different environments.