METHOD OF STEAM INJECTION PROFILING WITH UNSTABLE RADIOACTIVE ISOTOPES

A method of determining relative liquid and vapor phase steam profiles in a steam injection well utilizes an unstable radioactive isotope. A dual detector gamma ray logging tool is inserted into the well at a depth below the perforation zone. The unstable radioactive isotope is then injected into the steam flow, and it naturally hydrolyzes from a vapor phase into a liquid phase at a known rate, so that at a given time after injection, the relative proportions of the vapor phase and the liquid phase can be determined. The transit times of the vapor and liquid phases to pass between the gamma ray detectors is measured and the above steps are then repeated at a second location. The amount of fluid entering a formation between the first and second locations can the be determined.