Improperly plugged or unplugged abandoned wells which penetrate an injection zone may provide a conduit for migration of injected fluids into freshwater aquifers. To help minimize this serious environmental threat, all abandoned wells within an area of review around a proposed injection well should be located and their condition assessed. A search for abandoned wells may have three different objectives: (1) to provide an overview of the presence of absence of abandoned wells within an area, (2) to determine the status of a particular well and establish the potential impact of that well, and (3) to actually field locate the abandoned well. The scope of the search may encompass all or any combination of these objectives before the search is completed. This document contains a discussion of the application of methods which historically have been used to locate abandoned wells, and technologies which may not have been for that purpose but may have future application.

"This report was submitted in partial fulfillment of Contract No. CR-809353 by the National Water Well Association under the sponsorship of the Robert S. Kerr Environmental Research Laboratory, Ada, Oklahoma and in cooperation with East Central University Environmental Research Institute, Ada, Oklahoma"--Page v. Includes bibliographical references (pages 118-123). "EPA-600/2-83-123."

METHODS HISTORICALLY USED TO LOCATE ABANDONED WELLS: Search of records -- Conversation with local residents -- Visual/Logical -- Aerial photographic interpretation -- Metal detectors -- Magnetometers -- Combustible gas indicators -- Excavation -- METHODS WHICH HAVE NOT HISTORICALLY BEEN USED TO LOCATE ABANDONED WELLS: Electrical resistivity -- Electromagnetic conductivity -- Ground penetrating radar -- Remote sensing -- Water level measurement in surrounding wells -- Injection.