Method and apparatus for measuring horizontal fluid flow in downhole formations using injected radioactive tracer monitoring
 Formation fluid flows in earth formations (37) opposite a perforated (40) wellbore (15) zone are measured and monitored by injecting radioactive tracers (50) into the perforations (40), blocking the perforations to retain the tracers (50) in the formation (37), monitoring the apparent decay rates (58) of the injected tracers (50), and then determining the rate at which the tracers are being carrier away by fluid movements in the formation (37). From this the flow rate (60) of the fluids in the earth formations (37) adjacent the borehole interval is inferred. 
Halliburton Logging Services, Inc.
E
E21B
inventional
Harry D. Dan M. Larry L.
Smith, Jr. Arnold Gadeken