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An Evaluation of Helicopter and Ground Methods for Locating Existing Wells
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 19th EEGS Symposium on the Application of Geophysics to Engineering and Environmental Problems, Apr 2006, cp-181-00002
Abstract
Improperly plugged, abandoned wells are a hazard in areas undergoing enhanced oil recovery using liquid CO2 floods. Likewise, abandoned wells represent the greatest threat to the permanence of CO2 sequestration in geologic formations. This paper describes the results of cooperative research by the National Energy Technology Laboratory and Fugro Airborne Surveys to evaluate the use of helicopter magnetic, radiometric, and methanometric surveys to locate wells, paricularly unplugged or improperly plugged wells. Two surveys were conducted on a 1 square mile section of the Salt Creek Oilfield near Casper, Wyoming. Flight 1 was carried out with a horizontal gradient magnetometer (MIDAS II System)and a radiometric detector (Exploranium GR-820). The intent of flight 1 was to detect steel well casing using magnetometry and to detect radon daughter anomalies that may form around unplugged wells. Radiometric anomalies from radium substituted barite were also expected to occur in areas of petroleum related activities, particularly wells. Flight 2 was conducted using a compact differential absorption lidar system for the remote detection of methane plumes (Lasen). The intent of flight 2 was to detect methane that may be emitted into the atmosphere from unplugged wells. Taken together, the flights were intended to locate all steel-cased wells using magnetic detection and to determine which wells were unplugged or improperly plugged by detecting radon and methane leaking from these wells.