Detection of behind casing water flow at an angle to the axis of a well borehole
 Methods and apparatus are disclosed herein for detecting undesired water flow at an angle to the axis of a well borehole. The borehole envisons is irradiated with 14 MEV neutrons resulting in the in situ creation of the radioactive tracer element N.sup.16 in the flowing water. Two spaced gamma ray detectors are used to sense gamma rays produced by the decay of this radioactive isotope. The distance from the center of each detector to the center of the flowing water is used to establish the angle of flow with respect to the well tool, the linear flow rate of the flow v and the volume flow rate V of the undesired water flow. 
Texaco Inc.
G E G G
G01P E21B G01F G01V
inventional inventional inventional inventional
Dan M. Hans J.
Arnold Paap